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  • Fisheries  (13,279)
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  • 1
    ISSN: 1572-8366
    Keywords: Environment ; Fisheries ; Fordism ; Nation-State ; Regulation ; Supranational State ; Transnational corporations ; Transnational State
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This analysis uses an analytical frameworkgrounded in political economy perspectives of theglobalization of the agro-food sector combined with acase study approach focusing on the Marine StewardshipCouncil (MSC) to inform discussions regarding thecharacteristics of societal regulation in thepost-Fordist era. More specifically, this analysisuses the case of the emergence of the MSC toinvestigate propositions regarding the existence of,and location of, nascent forms of a transnationalState. The MSC proposes to regulate the certificationof sustainable fisheries at the global level throughan eco-labeling program. The MSC was created in 1996by the transnational environmental organization theWorld Wildlife Fund and the transnational corporationUnilever. The emergence of the MSC has generatedheated discussion in fisheries management circles thatis in general divided along North/South lines. Thisanalysis indicates that the case of the MSC providesvaluable insights into the possible characteristics ofsupranational regulatory mechanisms that might emulatethe role of the nation-State in the post-Fordist era.
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  • 2
    ISSN: 1432-1009
    Keywords: Coastal zone Management ; Fisheries ; Marshes ; Wetlands ; Louisiana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract This paper examines causes and consequences of wetland losses in coastal Louisiana. Land loss is a cumulative impact, the result of many impacts both natural and artificial. Natural losses are caused by subsidence, decay of abandoned river deltas, waves, and storms. Artificial losses result from flood-control practices, impoundments, and dredging and subsequent erosion of artificial channels. Wetland loss also results from spoil disposal upon wetlands and land reclamation projects. Total land loss in Louisiana's coastal zone is at least 4,300 ha/year. Some wetlands are converted to spoil banks and other eco-systems so that wetland losses are probably two to three times higher. Annual wetland losses in the Barataria Bay basin are 2.6% of the wetland area. Human activities are the principal determinants of land loss. The present total wetland area directly lost because of canals may be close to 10% if spoil area is included. The interrelationship between hydrology, land, vegetation, substrate, subsidence, and sediment supply are complicated; however, hydrologic units with high canal density are generally associated with higher rates of land loss and the rate may be accelerating. Some cumulative impacts of land loss are increased saltwater intrusion, loss of capacity to buffer the impact of storms, and large additions of nutrients. One measure of the impact is that roughly $8–17 × 106 (U.S.A.) of fisheries products and services are lost annually in Louisiana. Viewed at the level of the hydrologic unit, land loss transcends differences in local vegetation, substrate, geology, and hydrology. Land management should therefore focus at that level of organization. Proper guideline recommendations require an appreciation of the long-term interrelations of the wetland estuarine system.
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  • 3
    ISSN: 1432-1009
    Keywords: Grass carp ; Biological control ; Nuisance aquatic weeds ; Fisheries ; Aquaculture ; Reproductive requirements ; Arkansas management plan ; Sterile hybrids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Grass carp (Ctenopharyngodon idella Val.) were introduced into the United States in 1963 as potential biological control agents for nuisance aquatic weeds. Since that time an oftentimes bitter controversy has raged over its effects on sportfishing, and its possible natural reproduction and naturalization in North America. This review considers the history, ecology, and present status of grass carp in the United States in light of the voluminous scientific research conducted since its importation. Particular attention is given to the role of grass carp in the fisheries management plans of Arkansas. Recent development of a sterile, triploid grass carp hybrid may lead to widespread use of grass carp to control nuisance aquatic weeds in culturally eutrophicated waters of the United States.
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  • 4
    ISSN: 1432-1009
    Keywords: Flushing ; Scouring ; Channel Maintenance ; Fisheries ; Trinity River
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The operation of Trinity and Lewiston Dams on the Trinity River in northern California in the United States, combined with severe watershed erosion, has jeopardized the existence of prime salmonid fisheries. Extreme streamflow depletion and stream sedimentation below Lewiston have resulted in heavy accumulation of coarse sediment on riffle gravel and filling of streambed pools, causing the destruction of spawning, nursery, and overwintering habitat for prized chinook salmon (Salmo gairdnerii) and steelhead trout (Oncorhynchus tschawytscha). Proposals to restore and maintain the degraded habitat include controlled one-time remedial peak flows or annual maintenance peak flows designed to flush the spawning gravel and scour the banks, deltas, and pools. The criteria for effective channel restoration or maintenance by streambed flushing and scouring are examined here, as well as the mechanics involved. The liabilities of releasing mammoth scouring-flushing flows approximating the magnitude that preceded reservoir construction make this option unviable. The resulting damage to fish habitat established under the postproject streamflow regime, as well as damage to human settlements in the floodplain, would be unacceptable, as would the opportunity costs to hydroelectric and irrigation water users. The technical feasibility of annual maintenance flushing flows depends upon associated mechanical and structural measures, particularly instream maintenance dredging of deep pools and construction of a sediment control dam on a tributary where watershed erosion is extreme. The cost effectiveness of a sediment dam with a limited useful economic life, combined with perpetual maintenance dredging, is questionable.
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  • 5
    ISSN: 1432-1009
    Keywords: Fisheries ; Phosphorus ; Contaminants ; Ecosystem ; Management ; Simulation model ; Great Lakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A simulation model was developed to describe linkages among fish food web, nutrient cycling, and contaminant processes in the southern basin of Lake Michigan. The model was used to examine possible effects of management actions and an exotic zooplankter (Bythotrephes) on Lake Michigan food web and contaminant dynamics. The model predicts that contaminant concentrations in salmonines will decrease by nearly 20% ifBythotrephes successfully establishes itself in the lake. The model suggests that this decrease will result from lowered transfer efficiencies within the food web and increased flux of contaminants to the hypolimnion. The model also indicates that phosphorus management will have little effect on contaminant concentrations in salmonines. The modeling exercise helped identify weaknesses in the data base (e.g., incomplete information on contaminant loadings and on the biomass, production, and ecological efficiencies of dominant organisms) that should be corrected in order to make reliable management decisions.
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  • 6
    ISSN: 1432-1009
    Keywords: Water control ; Floodplain ; Fisheries ; Bangladesh ; Chandpur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Bangladesh is a very flat delta built up by the Ganges—Brahmaputra—Meghna/Barak river systems. Because of its geographical location, floods cause huge destruction of lives and properties almost every year. Water control programs have been undertaken to enhance development through mitigating the threat of disasters. This structural approach to flood hazard has severely affected floodplain fisheries that supply the major share of protein to rural Bangladesh, as exemplified by the Chandpur Irrigation Project. Although the regulated environment of the Chandpur project has become favorable for closed-water cultured fish farming, the natural open-water fishery loss has been substantial. Results from research show that fish yields were better under preproject conditions. Under project conditions per capita fish consumption has dropped significantly, and the price of fish has risen beyond the means of the poor people, so that fish protein in the diet of poor people is gradually declining. Bangladesh is planning to expand water control facilities to the remaining flood-prone areas in the next 15–20 years. This will cause further loss of floodplain fisheries. If prices for closed-water fish remain beyond the buying power of the poor, alternative sources of cheap protein will be required.
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  • 7
    ISSN: 1432-1009
    Keywords: Reservoir ; Fisheries ; Breeding and wintering waterbirds ; Raising water levels ; Habitat change
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A new, higher dam was installed at Kerkini Reservoir in 1982, causing habitat and landscape disruption. A decrease in the area of grassland and shallow water areas, the rapid disappearance of reedbeds, the appearance of beds ofNymphaea, and the disappearance of half the forest area were all observed between 1982 and 1991. With the new hydrological regime, a lacustrine system was created, with an extensive, rather deep (4–8 m), pelagic zone favorable for the development of coarse fish species throughout the year. After 1982, an increase in fishing effort and a change in the relative abundance of fish species in the catch, including the disappearance of eels and wels, were observed. The impact of the rise in the water level of breeding aquatic birds led to a general decline in species typical of marshy habitats in favor of species preferring deeper open water habitats. A decrease was recorded in bird species that feed largely on invertebrates and to a lesser extent fish (e.g., glossy ibis) and that require extensive shallow feeding areas. There was a decline in geese, whose nests were regularly flooded, and a major increase in piscivorous birds, particularly diving birds (e.g., cormorants), which prefer deeper open water and benefitted directly from the large increase in coarse fish biomass. The disappearance of birds breeding in flooded meadows (e.g., black-winged stilts) and of those restricted to reedbeds (e.g., marsh harrier) occurred from 1983. Over the same period, the changes in populations of wintering birds at Kerkini were different from those occurring in other wetlands in northern Greece. The changes recorded in the populations of wintering birds at Kerkini did not therefore result from overall regional trends but from the major habitat modifications that occurred to this wetland. As for breeding birds, strictly piscivorous species increased greatly as a result of the increased availability of fish, but also due to the appearance of many suitable night roosting sites (flooded trees) and to the great increase in the area of open water greater than 2 m deep. Today, Kerkini has become the most important breeding site in Greece for a majority of colonial waterbirds. In contrast, wintering shorebirds practically disappeared. The many changes recorded in the status of breeding and wintering birds at Kerkini can mostly be explained by the changes that occurred in the functioning of the ecosystem and in the habitat structure following the inauguration of the new hydrological regime. These changes did not all occur at the same time: some were immediate and others required a delay before they could be detected.
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  • 8
    ISSN: 1573-5133
    Keywords: Fish introductions ; Africa ; Cichlids ; Barbus ; Haplochromis ; Lake management ; Fisheries
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Cyprinid fishes apparently constituted the major part of the original fish fauna in Lake Luhondo, Rwanda, at least until 1934. At that time only three species, all cyprinids, were known from the lake:Barbus neumayeri, a small barbel, very common in the lake (described from the lake asBarbus luhondo) and two larger cyprinid species:Barbus microbarbis andVaricorhinus ruandae. These two large species were probably not very common in the lake. Between 1935 and 1938 some youngTilapia were introduced into Lake Luhondo. Since then and certainly since 1952 the large cyprinids seem to have disappeared completely from the lake. The smallBarbus neumayeri has become extremely rare; at present it survives only in some small tributaries of the lake. In the lake itselfTilapia andHaplochromis species are now the dominant fauna. A survey of the available information is given.
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  • 9
    ISSN: 1573-5133
    Keywords: Chondrichthyes ; Elasmobranchs ; Fisheries ; Ageing methods ; Growth rates ; Gestation periods ; Maturity ; Vertebral bands ; Weight-length relationships ; Life histories
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The silky shark, Carcharhinus falciformis, and scalloped hammerhead, Sphyrna lewini, represent >80% of the shark by-catch of the winter swordfish/tuna longline fishery of the northwestern Gulf of Mexico. This catch represents a potential supplemental fishery, yet little is known of the life histories of the two species. This report relates reproductive biology data to age and growth estimates for 135 C. falciformis and 78 S. lewini. Unlike other regional populations, C. falciformis in the Gulf of Mexico may have a seasonal 12 month gestation period. Males mature at 210–220 cm TL (6–7 yr); females at >225 cm TL (7–9 yr). Application of age at length data for combined sexes produced von Bertalanffy growth model parameter estimates of L∞ = 291 cm TL, K = 0.153, t0 = −2.2 yr. Adult male S. lewini outnumbered adult females in catches because of differences in the distributions of the sexually segregated population. Males mature at 180 cm TL (10 yr); females at 250 cm TL (15 yr). von Bertalanffy parameter estimates for combined sexes of this species were L∞ = 329 cm TL, K = 0.073, to = −2.2 yr.
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  • 10
    ISSN: 1573-5133
    Keywords: Production ; Fisheries ; Population dynamics ; Energetics ; Fishes ; Competition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Production rates of seven species of fishes were determined for one year in a 0.95 ha pond. Total annual production of all fishes in the pond was 209 g m−2y−1 (after the subtraction of 16.2 g m−2y−1 of negative production). Over 90% of the production occurred in the months of June through September, with young-of-the-year fishes contributing 84% of the total. When Y of Y fishes shifted to benthic diets in the spring, the small biomass of benthos available could not sustain the large biomas of fish. Severe competition for the available food then resulted in decreased production rates for the entire fish taxocene.
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  • 11
    ISSN: 1573-5133
    Keywords: California ; Elasmobranchs ; Exploitation ; Fisheries ; Life history ; Tagging ; Triakidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The age, growth, and sexual maturation of the leopard shark, Triakis semifasciata, from central California were studied. Growth band counts in vertebral centra of 162 leopard sharks produced von Bertalanffy growth curves with L∞, K. and to parameters of 1536 mm. 0.082, and -2.31, respectively, for both sexes combined. The L8 value for females (1602 mm TL) was slightly but insignificantly higher than for males (1499 mm TL), but the K and to values were almost identical. Seasonal changes in size modes of young-of-the-year leopard sharks, centrum edge characteristics, and growth and tetracycline mark-recapture from the field were used to validate annual deposition of vertebral centrum band pairs. Sexual maturity was evaluated by the gonads and presence of sperm and eggs; males mature at 7 yr and at about 63% of asymptotic length, and females mature at 10 yr, and at about 72% of asymptotic length. This slow growth, late maturity, and relatively low fecundity may increase their susceptibility to over-exploitation.
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  • 12
    ISSN: 1573-5133
    Keywords: Cyprinids ; Ethiopia ; Morphotypes ; Food-niche ; Biodiversity ; Feeding ; Evolution ; Fisheries ; Resource partitioning ; Piscivory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis In October–December 1990, the large barbs (Barbus) that contribute more than 35% of the catch in lake Tana (northern Ethiopia) were studied. Previous authors (Rüppell 1837, Boulenger 1902,1911, Bini 1940) described from 6 to 23 (sub)species for the lake. Banister (1973) lumped all of these into one subspecies: Barbus intermedius intermedius Rüppell,1837. We found that the Lake Tana Barbus could be readily categorized in at least 13 discrete morphotypes, some of which were already distinguished by local fishermen. None of the known descriptions are adequate to distinguish the barbs unambiguously, which is important for monitoring and management of developing fisheries. Intermediates between morphotypes were rare (< 10%). By applying canonical discriminant analysis on a set of 17 morphometric characters (including some directly associated with feeding) our initial morphotype-distinction was confirmed. Also, differences between the morphotypes in distribution, related to depth and substratum were found, as well as differences in intestinal contents, a key to the food-niche. The high number of piscivorous morphotypes (8 out of 13) was striking as piscivory is relatively rare among cyprinids. Piscivory was found to be highly correlated with morphological (feeding related) characters. The presence of discrete morphotypes, that also differ in food-niche and distribution, strongly suggests that several distinct populations exist, that may be (partly or completely) reproductively segregated. Knowledge about these populations, that may represent separate units of fish stock, is of crucial importance for the management of sustainable fisheries and protection of the biodiversity in Lake Tana. It is possible that several species or even a unique cyprinid species flock are present, that urgently need protection.
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  • 13
    ISSN: 1573-5133
    Keywords: Ecology ; Behaviour ; Evolution ; Cichlids ; Fisheries ; Conservation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Ecological conditions in tropical lacustrine systems are considered by focusing on the evolution, maintenance, exploitation and vulnerability of fish communities in the African Great Lakes. The exceptionally high biodiversities in the littoral/sublittoral zones of the very ancient, deep, clear, permanently stratified rift lakes Tanganyika and Malawi, are contrasted with the simpler systems in their pelagic zones, also with biodiversity in the much younger, shallower Victoria, the world's largest tropical lake.
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  • 14
    ISSN: 1573-2975
    Keywords: Systems of Knowledge ; Local Knowledge ; Fisheries ; Resource Management
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Sociology
    Notes: Abstract During the last 20 years, the existence of rich systems of local knowledge, and their vital support to resource use and management regimes, has been demonstrated in a wide range of biological, physical and geographical domains, such as agriculture, animal husbandry, forestry and agroforestry, medicine, and marine science and fisheries. Local knowledge includes empirical and practical components that are fundamental to sustainable resource management. Among coastal-marine fishers, for example, regular catches and, often, long-term resource sustainment are ensured through the application of knowledge that encompasses empirical information on fish behaviour, marine physical environments, fish habitats and the interactions among ecosystem components, as well as complex fish taxonomies. Local knowledge is therefore an important cultural resource that guides and sustains the operation of customary management systems. The sets of rules that compose a fisheries management system derive directly from local concepts and knowledge of the resources on which the fishery is based. Beyond the practical and the empirical, it is essential to recognise the fundamental socio-cultural importance of local knowledge to any society. It is through knowledge transmission and socialisation that worldviews are constructed, social institutions perpetuated, customary practices established, and social roles defined. In this manner, local knowledge and its transmission, shape society and culture, and culture and society shape knowledge. Local knowledge is of great potential practical value. It can provide an important information base for local resources management, especially in the tropics, where conventionally-used data are usually scarce to non-existent, as well as providing a shortcut to pinpoint essential scientific research needs. To be useful for resources management, however, it must be systematically collected and scientifically verified, before being blended with complementary information derived from Western-based sciences. But local knowledge should not be looked on with only a short-term utilitarian eye. Arguments widely accepted for conserving biodiversity, for example, are also applicable to the intellectual cultural diversity encompassed in local knowledge systems: they should be conserved because their utility may only be revealed at some later date or owing to their intrinsic value as part of the world's global heritage. At least in cultures with a Western liberal tradition, more than lip-service is now being paid to alternative systems of knowledge. The denigration of alternative knowledge systems as backward, inefficient, inferior, and founded on myth and ignorance has recently begun to change. Many such practices are a logical, sophisticated and often still-evolving adaptation to risk, based on generations of empirical experience and arranged according to principles, philosophies and institutions that are radically different from those prevailing in Western scientific circles, and hence all-but incomprehensible to them. But steadfastly held prejudices remain powerful. In this presentation I describe the 'design principles' of local knowledge systems, with particular reference to coastal-marine fishing communities, and their social and practical usefulness. I then examine the economic, ideological and institutional factors that combine to perpetuate the marginalisation and neglect of local knowledge, and discuss some of the requirements for applying local knowledge in modern management.
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  • 15
    ISSN: 1573-5133
    Keywords: Cyanide ; Diversity ; Development ; Ecology ; Environment ; Fisheries ; Pollution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The biological diversity and productivity of Philippine coral reefs are threatened by siltation, destructive fishing methods, coral and shell collecting and overfishing. Destructive fishing includes: the widespread, illegal use of explosives; poisons such as sodium cyanide; muro-ami and kayakas fishing; and trawling. The recent decline in catch rates threatens the livelihood of 700 000 near-shore subsistence fishermen who catch 55% of the total landings. The new government under Corazon Aquino wishes to protect the marine environment through the creation of a viable marine conservation management plan, enforcement of existing laws and through cooperation between government, non-government and international agencies to provide education and research. The Department of Agriculture, which has the authority for fisheries, has designated the International Marinelife Alliance as the lead non-government agency involved with fund raising, net-training and finding alternatives to destructive fishing methods.
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  • 16
    ISSN: 1573-5133
    Keywords: Rockfish ; Longevity ; Reproductive value ; Fisheries ; Scorpaenidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The characteristics of lightly and heavily exploited Pacific ocean perch,Sebastes alutus, stocks are evaluated relative to the predictions of life history theory. These long-lived species (50–100 year lifespan) show limited phenotypic plasticity and have little buffering against the effects of reduced lifespan. Reduced stock abundance has generated some compensatory increase in growth rate. Length at first maturity varies only slightly with increased growth rate, although age at maturity may decrease by 1–4 years. Grooth increases yield larger (15–20%) size at age and increased reproductive effort at younger ages, but lower size-specific fecundity for these faster-growing fish. This suggests an energy allocation protocol favouring growth over reproduction in these long-lived animals. Rockfishes have late recruitment to fisheries (ages 10–15), and the detection time for results of management actions is equally long. Their vulnerability to overfishing means that indices of population changes, more representative of fishing effects than the catch rate index presently used, are required. Reproductive value indices are shown to be extremely sensitive and continuous with population abundance changes. Their incorporation into monitoring programs would permit more timely evaluation of management actions. Management policies developed for shorter-lived species are shown to be inappropriate for rockfishes. The need for an improved match in the time frame of the species' life history, and that of management strategies, is stressed.
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  • 17
    ISSN: 1573-5133
    Keywords: Fisheries ; Irrigation ; Reproductive seasonality ; Sarotherodon galilaeus ; Species richness ; Water quality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis A preliminary study of the ecology and commercial fish catches was carried out in the Toho-Todougba, Ahouangan and Dati lakes (1500 ha) in southern Benin (West Africa) over a period of 18 consecutive months. Water quality, species richness, and the reproductive biology of the dominant species, Sarotherodon galilaeus, were examined. Unlike Lagoon Toho-Todougba, lakes Ahouangan and Dati are less favourable for fish production because of their high total iron content and their relative low pH. The study revealed the existence of 19 species belonging to eleven (11) families: 16 species in Lagoon Toho-Todougba,12 in Lake Ahouangan, and 7 in Lake Dati. Lakes Ahouangan and Dati had a relatively high faunal similarity whereas Lagoon Toho-Todougba exhibited a relatively low faunal similarity with the former systems. In Lagoon Toho-Todougba, six cichlid species were the most important component of the fishery: Sarotherodon galilaeus, Tilapia guineensis, T. zillii, T. mariae, Chromidotilapia guntheri, Hemichromis fasciatus. Three catfish species Chrysichthys auratus, Clarias agboyiensis, and Clarias lazera were harvested in low abundances. Some other fish, such as Polypterus senegalus senegalus, Protopterus annectens and Heterotis niloticus were captured sporadically, with H. niloticus appearing more consistently in catches than the others. Although not abundant, Gymnarchus niloticus and the African pike, Hepsetus odoe, were almost always present in the catches. Ctenopoma kingsleyae appeared only in Ahouangan. Some predatory species, such as Notopterus afer and Xenomystus nigri, are encountered only in lakes Ahouangan and Dati. In Lagoon Toho-Todougba, Sarotherodon galilaeus had a sex ratio (♂: ♀) of 0.49:1, and size at maturation was estimated as 12.3 cm TL. The spawning period extended from May to September with the peak occurring in July. Fecundity was correlated to log-body length (r = 0.74) and log-body weight (r = 0.76). Fish catches were estimated at 389 kg ha−1 year−1; about 73% of which was Sarotherodon galilaeus. The overexploitation of juvenile fish and the use of this lagoon for the irrigation of palm tree plantations have reduced fish recruitment and mean size.
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  • 18
    ISSN: 1573-5133
    Keywords: Temperature ; Behavior ; Ecology ; Fisheries ; Fish ; Marine juveniles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Sixteen yearling winter flounder, tested individually for 3-day periods in electronic shuttleboxes, voluntarily occupied an 8–27°C range of temperature, with a modal final thermal preferendum of 18.5°C (mean 18.7°C, median 19°C, midpoint 17.5°C, s.d. 1.9°C, S k + 0.33). The locomotor activity pattern of the yearling fish in the laboratory was markedly nocturnal, with mean hourly nocturnal activity exceeding mean hourly diurnal activity by a factor of 3.4. Maximum activity occurred at 0300 EST, minimum activity at 1400 EST. While activity generally increased with temperature, a local activity minimum occurred at 18.7°C, coinciding with the 24-hour mean final thermal preferendum. Comparison of these laboratory data with previously published field data suggest that behavioral responses to temperature and light play significant roles in determining age- and size-specific differences in seasonal depth stratification and onshore-offshore distributions in this species.
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  • 19
    Publication Date: 2018-05-16
    Description: Food costs in rainbow trout farms are about 50% of production costs (Barrows et al., 2007). Because of inattention of most aquaculturists in exact calculation of FCR and not using qualified food, sometimes food costs will rise a lot and won't be economical. The newest method for fish food production is production during the process of extrusion. Extrusion process is processing materials with high temperature in a short time (HTST) and is done by combined operation of humidity, heat, mechanical energy and pressure (Watanabe and Pongmaneerat, 1993).
    Keywords: Aquaculture ; Fisheries
    Repository Name: Aquatic Commons
    Type: Article , PeerReviewed
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  • 20
    Publication Date: 2018-05-16
    Description: The coastal area of the Caspian Sea and Gorgan Bay are important ecosystems receiving discharge from their tributaries. In this study, concentration of lead (Pb), cadmium (Cd), zinc (Zn) and chromium (Cr) was seasonally determined at 8 sampling points during 2009-2010. Water samples were collected from the sampling stations and transferred to laboratory in polyethylene containers, whereas, sediment and benthic fauna samples were collected using a Van Veen grab. The levels of heavy metals were determined by atomic absorption spectroscopy method. Results showed that range of Pb, Cd, Cr and Zn in the water samples were 80-123, 61-97, 63-87 and 82-120 ppb, respectively and their ranges in the sediment samples were 479-1072, 98-293, 102-622 and 937-1577 ppb, respectively. The range of Pb, Cd, Cr and Zn in the benthos samples were 95-132, 59-110, 26-58 and 103-155 ppb, respectively. Zn and Pb were the most concentrate metals in all samples. Likewise, sediment had the highest heavy metal content amongst the samples. This study demonstrated that the level of metals in the environment is increasing, bringing a serious warning to industries and threat of man-made contamination, which can be restricted and a necessity to control ecosystem and food-chain pollution.
    Keywords: Biology ; Fisheries
    Repository Name: Aquatic Commons
    Type: Article , PeerReviewed
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  • 21
    Publication Date: 2018-05-16
    Description: Numerous reports on existence of white cysts in musculature of skipjack tuna Katsuwonus pelamis and lack of information about the quality of cysts and individual responses of fish to them led the authors to focus on this fish as a commercially valuable species. This study investigated the histopathologic responses of skipjack tuna to highly prevalent cystic larval stages of Trypanorhyncha. Some 92.25% of 400 examined skipjack tuna of Oman Sea (Iran) captured from processing center in Chabahar have been diagnosed infected by Trypanorhyncha Larvae through gross muscle examination. Minimum of 5 to maximum of 19 cysts were observed per each flank flesh with no significant difference between number of cysts from right (9 ± 4) and left flanks (10 ± 4) and also males and females (p>.05, t- student test (spss version 16)). Using hematoxylin and eosin (H&E) staining of 4µm sections of surrounded cysts with muscle and light microscopy observations each metacestode was distinguished encapsulated by surrounding fibrous cyst wall consists of thin inner layer and a thick outer layer with the minimal histopathologic changes around it. The highly prevalent Trypanorhyncha infection in Oman Sea represents the high rate of infection among elasmobranches. The ability of encapsulated parasite to escape from the immune system of the host is assumed as one reason for the observed minimal tissue response in infected fish and the continuation of infection among elasmobranches and teleosts of Omen Sea.
    Keywords: Biology ; Fisheries
    Repository Name: Aquatic Commons
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  • 22
    Publication Date: 2018-05-16
    Description: Acipenser stellatus is one of the most invaluable species of Sturgeon fishes in the world. The purpose of this study was to identify the resident microbial community from the gastrointestinal tract (GIT) of Acipenser stellatus. One hundred and twenty three fungi were isolated from the GIT of 7 Acipenser stellatus samples including Aspergillus spp (45.5%), Trichoderma spp (8.9%) and Cladophialophora spp (8.1%). Among different Aspergillus isolates, A. niger was the predominant species. Although, fungi were predominantly isolated from stomach (36.6%), but with respect to frequency of fungal isolates there were no significant differences between stomach and other parts of GI. In general, the bacterial isolates recovered were mostly gram negative and related to Enterobacteriaceae family such as Aeromonas, Pseudomonas and Salmonella species. The most bacterial species were isolated from intestine and pre stomach region (88.2%). It is concluded that A. niger and Aeromonas species were predominant fugal and bacterial microbes isolated from understudy fish GIT, respectively.
    Keywords: Biology ; Fisheries
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  • 23
    Publication Date: 2018-05-16
    Description: The study and research of abundance and diversity variation of fish larva (Ichthyoplankton stages) was done in Gowatr Bay during autumn 2006 - summer 2007. Five stations were selected for sampling, and Bongo-Net with 300µ mesh size was towing from bottom to surface. During of survey, totally 531 larvae belong to 11 families were collected and identified. The mean abundance estimated 12.17 larvae per 10 m^2, in which three fish larva family including: Gobiidae, Clupeidae and Engraulidae were dominant (86% of relative abundance). The result showed that there was significant differences between pre and post-monsoon fish larvae abundances (p<.05), and there were not significant differences between stations (p>.05). In pre-monsoon 4 families were identified of which Clupeidae introduced as indicator group, whereas in post-monsoon 10 families were identified and Gobiidae was indicator family, accompany with increase of diversity. PCA result was shown, temperature as the main factor affected on fish larvae assemblage was found with a significant decrease of 11.9 °C after monsoon phenomenon.
    Keywords: Biology ; Fisheries
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  • 24
    Publication Date: 2018-05-16
    Description: A Gram-negative, rod-shaped, motile and halophilic bacterium identified as Vibrio harveyi was isolated from hatchery-reared larval of Iran Shrimp Research Center following mass mortality. Seven isolates of Vibrio spp. were collected from nauplii of Litopenaeus vannamei and then were evaluated for characteristics including morphology, physiology and biochemistry. The results indicated that the isolates belonged to a single species that grew on Thiosulfate citrate bile sucrose agar and in 1.5 to 6% NaCl, positive lysine and ornithine decarboxylation and susceptible to O/129 disk. Identification of Vibrio harveyi strainIS01 (1 of 7 isolates) was confirmed by Polymerase Chain Reaction assay for Vibrio harveyi (expected amplicon 1493 bp). The 16S ribosomal DNA sequence (National Center for Biotechnology Information, GenBank accession number GU974342.1) gave 99% sequence identity to V. harveyi ATCC: 35084 (GenBank accession number EU130475.1).
    Keywords: Aquaculture ; Biology ; Fisheries
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  • 25
    Publication Date: 2018-05-16
    Description: In this study, sperm characteristics (motility parameters and ionic composition of seminal plasma) and effect of ions on motility (duration of motility of sperm and percentage of motile spermatozoa) and fertilization capacity (fertilization rate, hatching rate, survival rate and larvae length) were investigated in Ctenopharyngdon idella. The longest duration of motility obtained in solution containing 104 mM NaCl. The highest fertilization capacity was observed in solution containing 112 mML NaCl. Solutions containing different concentrations of KCl caused a decrease on the percentage of motile spermatozoa fertilization rate and hatching rate, but duration of sperm motility and survival rate were significantly higher in solution containing 440 and 320 mM KCl, respectively. There was a decreasing trend on motility when spermatozoa incubated in solutions containing MgCl2 compared to the control. Similarly, higher motility parameters in terms of percentage of motile spermatozoa and duration of sperm motility were observed in distilled water. The sperm motility just after activation was suppressed by concentrations of CaCl2 of 32 mg/dL or more. The maximum hatching rate, survival rate and larvae length were observed in 32 mg/dL CaCl2. Understanding the effects of these ions is helpful to the aquaculture industry as it allows for the development of optimal artificial reproduction methods and contributes towards the knowledge base of better short-term fish semen preservation conditions.
    Keywords: Aquaculture ; Biology ; Fisheries
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  • 26
    Publication Date: 2018-05-16
    Description: White spot syndrome virus (WSSV) is a pathogen that causes high mortality in shrimp culture in the whole world. Sequence analysis of WSSV has shown similarity of WSSV isolates in different countries with exception of a few variable genomic loci. This study investigated the sequence variation of some Iranian WSSV isolates and previously identified isolates. Samples were collected during target surveillance and were feed, broodstock, post-larvae, artemia, crabs, and wild and cultured shrimp of northern Persian Gulf (Boushehr and Khuzestan provinces). The open reading frame (ORF) 94 sequence of different Iranian WSSV isolates were amplified using specific primers from positive samples. The ORFs 94 sequence of positive samples were sequenced and registered in the Gene Bank and then compared to other WSSV isolates. The number of repeat units in ORF94 showed that WSSV isolates were varied in number. There are SNPs (G and T) in position 48 of RUs that varies in different Boushehr and Khuzestan isolates. Also these sequences were compared to Gene Bank WSSV isolates and showed a high similarity (>90%) to Southeast Asian countries. To our knowledge this is the first report of sequence analysis in Iranian WSSV isolates applications.
    Keywords: Aquaculture ; Biology ; Fisheries
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  • 27
    Publication Date: 2018-05-16
    Description: Three different varieties of cottonseed meal (CSM) were evaluated to measure the apparent digestibility coefficient (ADC) of the nutrients using chromic oxide (Cr2O3) as an indigestible marker. Five experimental diets were prepared and mixed with 1% of Cr2O3, 2% of mineral and vitamin each of which were premixed. Diet 1 was used as the control diet. Diets 2, 3, 4 and 5 were formulated using 70% of the control diet together with 30% of each of the cottonseed meal Pak (CSMP), cottonseed meal Sahel (CSMS), cottonseed meal Akra (CSMA), and soya bean meal (SBM), respectively, in three replications. The ADC of the three CSM varieties was measured to be 53.8-62.7%, 60.2-66.6% and 75.6-82.4% for dry matter, fat and crude protein, respectively. Survival rate for all fishes used in this study was more than 98%. Fishes fed with the CSM diets were not significantly different compared with those fed with the SBM diet in terms of survival rate (p>0.05). Apparent protein digestibility of CSMP and CSMS showed no significant difference with SBM (p>0.05). Therefore, it could be concluded that two kinds of CSM could be used as a replacement for SBM in rainbow trout as a protein source.
    Keywords: Biology ; Fisheries
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  • 28
    Publication Date: 2018-05-16
    Description: Seasonal variations of zooplankton communities were studied in the southern Caspian Sea for 4 successive seasons and 8 transects with 5 stations from 5 to 100 m depths which sampled during 2009. The zooplankton population constituted of 73.33% copepods, 24.21% rotifers, 2.23% cladocerans and 0.23% protozoans. Copepods were dominant at all stations with a density between 1456±531 ind. m-3 (Transect 8) to 4524±1215 ind. m-3 (transect 2). The predominant species of copepods was Acartia tonsa constituting 99.50% of all copepod populations. They were most abundant during warm months of summer in the upper layers (surface to 20 m depth) while rotifers replaced them during cold season. The maximum density of zooplankton was observed in the west decreasing towards the eastern parts of the sea.
    Keywords: Biology ; Fisheries
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  • 29
    Publication Date: 2018-05-16
    Description: Sushi, a very popular food worldwide became a popular ready-to-eat food selling in supermarkets, but it exhibit distinct features, which are associated with microbiological hazards. Therefore, MAP technology, known to reduce aerobic bacteria in fishery products, was used to improve quality of ready-to-eat salmon sushi in this study. Salmon sushi were packaged with air (control), 50%N2 /50%CO2 (MAP-a), and 100% CO2 (MAP-b), stored at 4 ±1°C for 6 days and analyzed every day. During the study, control samples taken the lowest sensory scores. The total color change (ΔE) was lower in MAP samples comparing to controls. Likewise, mesophilic and psychrophilic aerobic bacteria counts of gas-treated samples were significantly lower. These results show the positive effect of MAP technology on the quality of salmon sushi. Regarding the improving demand to ready-to-eat sushi selling in supermarkets, this result will be useful in further studies and commercial applications.
    Keywords: Chemistry ; Fisheries
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  • 30
    Publication Date: 2018-05-16
    Description: The effects of Mentha pulegium water extract dipping on quality and shelf life of silver carp during superchilled storage were investigated. Fish samples were treated with water extract of 1 and 3% M. pulegium, and then stored at -3 οC for 30 days. The control and the treated fish samples were analyzed periodically for chemical (pH, PV, TBA, TVB-N), and sensory characteristics. The results indicated that the effect of M. pulegium extract dipping on fish samples was to retain their good quality characteristics and extend the shelf life during superchilled storage, which was supported by the results of chemical and sensory evaluation analyses. In this respect, the sample supplemented with 3% water extract was more potent compared with the 1% one in extending the shelf life of fish fillets.
    Keywords: Aquaculture ; Fisheries
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  • 31
    Publication Date: 2018-05-16
    Description: Monthly samples of six fish farms from January 2010 to December 2010 in the northern Iran, Haraz River, were used to determine relationship between chemical parameters of main water, inlet and outlet and their effects on fish growth and production. Results revealed that concentration of nutrients in outlet was more than that of inlet of farms, and statistical analysis showed that there were significant differences between stations (p<0.05). The amount of phosphate in upstream farms was lower than that of downstream. There was statistically significant difference between nitrite nitrates, concentrations in different months. Total sulphide, phosphate and ammonium in inlets were 0.002±0.009 (mg/l), 0.215±0.113 (mg/l) and 0.022±0.018 (mg/l) respectively. In outlets there was 0.003±0.009 mg/l sulphide, 0.302±0.193 mg/l phosphate and 0.037±0.026 mg/l ammonium. Ammonium concentration, showed no significant difference (p>0.05) in different months. Correlation between daily growth, SGR, FCR, production and chemical parameters of water were analyzed by Pearson correlation. The results revealed negative correlation (α= 0.01) between nitrite and daily growth (P=0.004, Pearson correlation=-0.24), ammonium and SGR (P=0.0001, Pearson correlation=-0.272), although there were no correlation for FCR, and nutritional parameters (p>0.05).
    Keywords: Aquaculture ; Biology ; Chemistry ; Fisheries
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  • 32
    Publication Date: 2018-05-16
    Description: Geographic Information system and Remote Sensing in the field of marketing is used in this study to open up a wide range of its possible applications as the study assessed shellfish marketing in Kure Ultra Modern Market Minna Niger State. The aim was to develop a database of various shellfish product on sale at the market. The demographic profile, socio-economic characteristics of the marketers and problem associated with the marketing, 100 questionnaires were administered the analytical tool used were frequency distribution, tables, percentages and cost-benefit ratio. Returns from the interview and questionnaire were use to verify the result which depicts that both male and female were engage in the business with female forming the majority group (55%) and 45% men. Marketing of the shellfish was profitable which was attributed to realization of the significant of shellfish over meat. The high profit was recorded in raining seasoning (70%) while dry season sales were 30%. Species of shellfish marketed were crayfish, prawn, cockles, snail, shrimps and crabs. The study also shows that the shellfishes mostly sold are in fresh form (85%) while 15% are in dry form. Daily sales ranges from N1000-N5000, majority of the respondents (75%) patronize low-cost transportation means between N500-N1000. In every enterprise there must be a problem; most of the problem encountered by the respondents were lack of constant supply from the landing site which is mostly marine environment, inadequate storage facility, poor transportation, high tax charges and theft; all this attribute data and the co-ordinate of the selling point at the market were put into ArcGIS environment. Base on the findings, recommendations were profiled to the government and database kept for references.
    Keywords: Fisheries ; Management
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  • 33
    Publication Date: 2018-05-16
    Description: The shrimps were collected from three sampling sites: on the River Benue at Makurdi, Benue state, on the River Niger at Jebba and Lokoja and Idah at Kogi state from January to April, 2011. Macrobrachium felicinum and Atya gabonensis were sampled during this period, with Atya gabonensis occurring more abundantly. Condition factors of freshwater shrimps Atya gabonensis from the two water bodies in Nigeria range from 1.875for species in Jebba in March to 3.330 for Lokoja in March. The parameter ”b” of the length - weight relationship of the fresh water shrimps are less than three (rangingfrom 1.0233 for species from Lokoja in April to 2.7717 for species from Makurdi in Feburary). These values suggest negative allometric growth. The length frequency of freshwater shrimps sampled shows that peak populations of length groups occurred in April for species from Jebba and Makurdi while peaks occurred in January for species from Lokoja.Peak frequencies were observed in length of 4.0 - 5. 4cm and 8.5 - 9.9cm in January as well as 5.5 -6.9cm for species from Lokoja and in the group of 5.5 - 6.9cm in April for species from Makurdi and 7.0-8.4cm in April for both Makurdi and Jebba.
    Keywords: Fisheries
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  • 34
    Publication Date: 2018-05-16
    Description: A study was conducted to investigate the status of artisanal fishery in Hadejia emirate of Jigawa state, Nigeria using a total of 192 well structured questionnaires in eight local government areas. The questionnaire captured information on biodata of respondents, water bodies and their uses, types of fish caught, level of catch and fishing gears used. The results obtained showed that fishing was mostly practices by male (79.69%), within the age of 25-35 years (33.86%) and married (61.46%) and most of them were found to be at tertiary institution of learning (55.73%). The study also revealed that majority used rivers as water source (52.08%) while only (31.25%) used the rivers for fishing and majority of their catch were Tilapia and Clarias (72.92%) with (52.60%) catching a large number above 30 per day. During catching 65 (33.85%) used Gill net, 52 (27.08%) used Cast net, 45 (23.44%) used Hook and line, while only 30 (15.63%) used Seine net.
    Keywords: Fisheries
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  • 35
    Publication Date: 2018-05-16
    Description: Gymnarchus niloticus is the only species of the family Gymnarchidae. It is a popular food fish in most parts of Africa where it is greatly esteemed. In some culture, it is offered as a special gift to leaders during festive seasons, while in some others it is an important part of items presented by a suitor to the parents of a girl at the time of betrothal. It can therefore be inferred that G. niloticus is not only important as food fish with economic significance, but also plays vital roles in the socio-cultural life of some African tribes. The supply of this important species still depends largely on the catch from the wild. However, based on the method of catch, it has been classified as endangered. A close examination of the ecological factors in the floodplain (where it migrates to breed), revealed strong influence on the breeding and survival of the fish. The level of rainfall determines the extent of floodplain inundation, and the abundance and survival of the flora and fauna in the area. These in turn determine the availability of breeding substrates and natural food sources for the various stages of G. niloticus. Therefore, rainfall, the flora and the fauna of the floodplain play vital roles in the breeding and survival of G. niloticus in nature. To ensure the conservation of this important species, controlled propagation strategies that draws on the influence of prevailing ecological factors in the floodplain is recommended. This will ensure conservation, and protect the economic and socio-cultural significance of G. niloticus.
    Keywords: Aquaculture ; Ecology ; Fisheries
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  • 36
    Publication Date: 2018-05-16
    Description: Acceptance of fish spring roll produced from Tilapia and Catfish were evaluated in an attempt to explore the possibilities of better utilization of undersized Tilapia and Catfish species. The products were produced with cooked potatoes (20%) egg (0.5%), milk (0.21%), butter(10.47%), flour(41.87%), vegetable oil(16.75%), carrot(0.46%), pepper (0.04%), made up to 100% with 10% inclusion of Tilapia in Tilapia spring roll and Catfish in Catfish spring roll. Tilapia and Catfish were boiled in a boiling pot before deboning for 10 minutes and then mashed for 5 minutes. The vegetables were chopped and steamed in a steaming pot for 5 minutes. 41.87% of flour was mixed together with steamed fishes and vegetable and rolled out into cylindrical shape of one inch thickness, deep fried in 800ml of vegetable oil and then allowed to cool. The acceptance was evaluated with 25 man panel based on taste, flavor, colour and texture. 80% of the panelist preferred spring roll made from Tilapia to those made from Catfish. 90%$ like the texture and flavor of spring roll made from catfish than that of Tilapia. There was higher consumer acceptability for spring roll made from Tilapia. In the flavor and colour of the spring roll, there was no significant difference observed between rolls made from catfish and Tilapia. Commercialization of these products can contribute to diversification in the fish industry through better utilization of undersized Tilapia and Catfish.
    Keywords: Ecology ; Fisheries
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  • 37
    Publication Date: 2018-05-16
    Description: A survey of the fisheries of river Niger at Yauri was conducted with the aid of questionnaires administered randomly at four (4) landing sites of Tashan Kasuwa (main market), Gidan-ruwa, Yabon-ruwa and Hutawa. A total of fifty (50) questionnaires were administered in all the villages. From the research work it was found that 76 % of the fishermen operate on full time basis while 24 % operate on part time basis. Out of the 50 fishermen interviewed only 46% were licensed to operate there. The type of fishing gears and equipments used in Yauri are hook and line, cast net, gill net and seine net. About 46 % of the fishermen were found using mesh size less than 2.0 cm. The dominant fish species caught during flood and dry seasons include Clarias spp., Lates niloticus respectively. Higher catches are made in the months of March and April. All the fishermen interviewed (100%) do not process their fish but disposed them off fresh. Sixty percent of the fishermen belong to different cooperative societies, while 40% do not belong to any cooperative society. The problem associated with fishing operation at Yauri includes that of lack of credit facilities, lack of extension agents, and high cost of fishing items, poor road network and remote location of the fishing village.
    Keywords: Fisheries
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  • 38
    Publication Date: 2018-05-16
    Description: This study was carried out in order to assess the use of solar tent dryer in some selected fishing settlement (Yobe, Daban Masara, Tumbun Beriberi and fish Dam) in Kukawa Local Government. Secondary and Primary data were used in this research. Secondary data were obtained from various literatues while primary data were obtained through the use of structured questionnaires. A total number of 60 respondents were randomly selected and interviewed: Fifteen from each settlement (fish processors). Simple percentages were used in analyzing the data. Findings revealed that, majority of the respondents (fish processors) 80% were not aware of the existence of solar tent dryer that can be used for drying fish, only 20% were aware of solar tent dryer.Among these respondents who are aware of solar tent dryer, only 3.33% have used it. The general perceptions of the respondents believe that they will use it if they are provided with the solar tent dryer. The level of awareness on the use of solar tent dryer for fish processing is very low, there is need for intensive awareness creation, through fishery extension workers.
    Keywords: Fisheries
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  • 39
    Publication Date: 2018-05-16
    Description: Human activities in natural environments are among the most important recreational needs. Monthly studies of tourism characteristics was conducted during wet and dry seasons, over a two year period in the three landscapes along the 6817.7m length of Agbokim waterfalls by using a close-ended pre-coded survey instrument. Through MANOVA analysis of the 1780 respondents, we found strong positive association between peoples visits to the recreational areas and the type of landscape in which the respondents felt happy. People who felt happier in landscape dominated by waterfalls, visit the middle reaches of the river for outdoor recreation more often, while people who feel happy in landscapes dominated by slow water current with an extensive wide area and floodplains, visit downstream reaches of the waterfalls more often. Activities performed more often along downstream reaches include fishing, bathing/swimming, boating and hunting while more frequent activities in the middle reaches (waterfalls) include taking photographs, picnics, enjoying nature, outing with family and friends, looking at view, resting and relaxing.
    Keywords: Fisheries ; Law
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  • 40
    Publication Date: 2018-05-16
    Description: A study was carried out on the fatty-acid composition of Macrobrachium vollenhovenii (African river prawn) in Ogun estuary, Ogun State, Nigeria. Sexes and size groups were considered during the study. Fatty-acid analysis was done in triplicates and data obtained were analyzed using descriptive statistics, analysis of variance and Duncan's multiple range tests. Fatty acids analysed which included oleic acid, linoleic acid,' stearic acid, myristic acid, palmitic acid and lauric acid were classified into saturated and monounsaturated fatty acids. All values of saturated fatty acids were higher in female (29.64%) than in male (25.50%) p< 0.05. So also the monounsaturated fatty acid also showed higher value in female (29.64%) than in male (25.50%). All fatty- acid values were higher in female M. vollenhovenii than in male. Meanwhile, myristic acid was highest in the two sexes and the combined sexes, (35.68% female), (33.14% male) and (34.74% combined sexes). The fatty-acid components were not influenced by the size of the fish. This study clearly indicated that the nutritive value of M. vollenhovenii is quite well comparable to the edible species of decapods already studied (shrimps, prawns and lobsters) and could be included in both human and livestock diets.
    Keywords: Fisheries
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  • 41
    Publication Date: 2018-05-16
    Description: This study focuses on Anguilliformes specimens revising which collected during 2006-08 in some Iranian museums. For this study, all museum samples from Iranian coastal waters of the Persian Gulf and Oman Sea were investigated. The results indicated that species diversity in the Iranian waters can be classified into six families of Anguilliformes (eels and morays fishes). A total of 11 species - consisting of six families have been identified, of these the highest species diversity belongs to the Muraenidae with five genus and eight species. Also, there were two endemic species Muraenesox cinereus (Muraenesocidae) and Gymnothorax undulatus (Muraenidae). More than ten rare species were the first report and record from Iranian territorial waters. There are Ichthyapus acuticeps, Synaphobranchus affinis, Strophidon sathete, Rhinomuraena quaesita, Gymnothorax johnsoni, G. kidako, Muraenesox bagio, Pseudoxenomystax albescens, Muraenesox talabonoides, and Conger cinereus cinereus.
    Keywords: Biology ; Fisheries
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  • 42
    Publication Date: 2018-05-16
    Description: Infectious Pancreatic Necrosis Virus (IPNV) is the causal agent of a highly contagious disease that affects many species of fish and shellfish. This virus causes economically important diseases of farmed rainbow trout, Oncorhynchus mykiss, in Iran which is often associated with the transmission of pathogens from European resources. In this study, moribund rainbow trout fry were collected during an outbreak of IPNV in three different fish farms in one northern province (Mazandaran), and two west provinces (Chaharmahal and Bakhtiari, and Kohgiluyeh and Boyer Ahmad) of Iran. We investigated full genome sequence of Iranian IPNV and compared it with previously identified IPNV sequences. The sequences of different structural and non-structural protein genes were compared with other aquatic birnaviruses sequenced to date. Our results showed that the Iranian isolate fall within genogroup 5, serotype A2 strain SP, having 99 % identity with the strain 1146 from Spain. These results suggest that the Iranian isolate may have originated from Europe.
    Keywords: Aquaculture ; Biology ; Fisheries
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  • 43
    Publication Date: 2018-05-16
    Description: Flat bottom boat (Rowing Punt) 4.27M length overall (LOA) was designed and constructed using plywood and fiber glass materials. The boat posses features like easy construction stability and high capacity to carry load. Other features include least cost light weight, shallow draft of 9cm easy maneuverability. The light displacement (weight empty) is 96.6kg which is similar to local boat of same size. The capacity of the boat 544kg (8 person) and total cost of production was N41,150.00 which is not beyond the reach of an average fisherman. The Rowing Punt easily propelled by oaring which makes it adequate for fishing activities on shallow water bodies. Such easily maneuvered craft can also be used for recreation which include, sport fishing, and boating.
    Keywords: Fisheries
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  • 44
    Publication Date: 2018-05-16
    Description: The rapid growth of aquaculture is accompanied by increased discharge of nutrient-rich wastewaters into rivers and coastal waters leading to eutrophication and deterioration of water quality. Seaweeds are suitable candidates to reduce dissolved inorganic nutrient concentration discharged through aquaculture effluent, and can improve water quality and allow for sustainable aquaculture. In this study the de-eutrophication ability of Ulva reticulata was investigated in a shrimp hatchery in Kuala Selangor, Malaysia by evaluating its ability to remove nutrients from shrimp brood stock effluent (SBE) in a batch culture system. The biofiltration ability of U. reticulata was confirmed by the significant reduction in nutrient concentrations during a 12 day period. The concentration of ammoniacal-nitrogen (NH3-N) was reduced by 100 % (after 12 h), nitrite (NO2-N) by 100 % (after 18 h), orthophosphate (PO4-P) by 89 % (after 12 days) and nitrate (NO3-N) by 33 % (after 12 days). An 18.5 % increase in biomass of the seaweed over the experimental period was also observed. The mean relative growth rate (RGR) of U. reticulata reached 1.6±0.1 % d^-1. The U. reticulata grew well in SBE, producing protein (6.1 ±1.1 %) and carbohydrate (39.9 ±4.5 %). Carbohydrate (P<0.05) and protein (p>0.05) content in seaweed growing in SBE were higher than seawater. The results of this study indicate that U. reticulata can be used directly as an effective biofilter for nutrient removal from shrimp hatchery effluent.
    Keywords: Aquaculture ; Biology ; Fisheries
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  • 45
    Publication Date: 2018-05-16
    Description: This paper examines the importance of Prosopis Africana as the most abundant tree in Baga and environs. Despite its abundance fish processors prefer the other trees that are almost becoming scarce especially Acacia Nolitica for fish smoking. There is need for awareness to adapt the use of Prosopis Africana for environmental sustainability and preservation of other trees not to go into extinction.
    Keywords: Fisheries ; Law
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  • 46
    Publication Date: 2018-05-16
    Description: Effects of salinity on fertilization, embryonic stage, and early larval development and growth performances of short-spined white sea urchin, Salmacis sphaeroides were conducted under a controlled laboratory condition. The experiment was carried out with seven salinity treatments (15, 20, 25, 30, 35, 40 and 45 PSU), each of which was triplicated. Significantly highest fertilization success was achieved at 30 PSU, followed by those at 25, 35, 20, 40 and 45 PSU, while the lowest value was obtained at 15 PSU, decreased with increasing and decreasing salinities (p<.05).The time required to reach these embryonic and larval stages was increased with the salinity deviations from 30 till the extent to 25 and 35 PSU. No significant differences (p>.05) were noted among these three salinity levels on prism larval length and width. However, significance differences (p>.05) were noted in morphometric characters of 2-arm and 4-arm pluteus larvae. The findings of the this study indicate that S. sphaeroides is stenohaline and do not survive and develop out of the range from 25 to 35 PSU.
    Keywords: Biology ; Fisheries
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  • 47
    Publication Date: 2018-05-16
    Description: Current microbial methodologies to determine fish quality are laborious and have long time required to obtain results. The impediometric technique as a rapid sensitive method was used to determine the correlation between impedance detection times (IDTs) and conventional reference psychrophilic and mesophilic plate counts of fish in order to develop models for predicting the microbial quality and determining fish shelf-life. The changes in sensorial factors, psychrophilic and mesophilic bacterial loads of ice stored fresh silver pomfret (Pampus argenteus) were measured by two different methods including conventional reference plating techniques and also impediometric monitoring method at 0, 3, 6, 9, 12, 15, 18, 21, 24 and 27 days of storage. The primary psychrophilic (3.44 ± 0.69 logCFU/g) and mesophilic (3.64 ± 1.08 logCFU/g) bacterial loads increased to more than acceptable limit (6 logCFU/g) on days 12 and 21, respectively. The calibration curves for the two methods and their equations were designed with linear regression models. IDTs were highly correlated with psychrophilic (r=-0.9614) and mesophilic (r=-0.9547) bacterial loads. This study suggests that impediometric technique can be used as a rapid and reliable method to accurate estimation of silver pomfret bacterial loads and determine its shelf-life as seafood. According to results, the sensorial data were correlated with psychrophic bacterial load. The shelf-life of ice stored silver pomfret determined 9-12 days based on sensorial data and psychrophic bacterial load.
    Keywords: Fisheries
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  • 48
    Publication Date: 2018-05-16
    Description: The objective of current study was to investigate the effects of whey protein coating on the quality of common kilka during frozen storage period. For this study, common kilka was coated with 12% whey protein concentration. Also, non-coated kilka was used as a control sample. Coated and non-coated samples were then stored at -18°C for six months. Bacterial, chemical and sensory properties of the samples were determined in each month. Results showed that total bacterial counts and Staphylococcus bacteria count were lower in the test samples compared to the control samples. Coliform, Escherichia coli and Pseudomonas bacterial contamination were negative till the end of the storage period in the covered samples. Chemical factors consisting of humidity, protein, lipid, ash and calories were higher in the test samples compared to the control samples. Peroxide value, free fatty acids, thiobarbituric acid, TVB-N and pH were lower in the test samples. Sensory tests had a better quality in the test samples compared to the control samples. No statistically significant decreases were observed in chemical factors in the covered samples compared to the control samples (p<.05). In sensory specifications, there was a significant difference between the covered samples and the control samples (p<.05). According to the results of experiments and statistical analysis, the covered samples had a favorable quality till the end of the storage period but the control samples had lost their quality.
    Keywords: Chemistry ; Fisheries
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  • 49
    Publication Date: 2018-05-16
    Description: The visceral storage fat and liver of patin catfish (Pangasianodon hypophthalmus) are normally discarded, which incurs cost and can cause environmental pollution. However, these may be potential sources to extract fish oil. The proximate and fatty acid compositions of liver and fatty tissue of patin catfish were investigated to evaluate the suitability of these by-products for extracting fish oil. Fat was extracted using a low temperature solvent extraction method. The average fat content of fatty tissue and liver of females were 77.64 and 11.71%, respectively, whereas in males this was 73.23 and 9.59%, respectively. Fatty acids found in the extracted oil of these byproducts were C12:0, C14:0, C14:1, C16:0, C16:1, C18:0, C18:1, C18:2, C18:3, C18:4, C20:0, C20:1, C20:4, C20:5, and C22:6. The major fatty acids presented in these tissues were palmitic (C16:0), oleic (C18:1 n-9), and linoleic acid (C18:2 n-6). The total amount of polyunsaturated fatty acids of liver from male and female patin catfish were 13.31 and 13.30%, respectively, whereas in the fatty tissue these were 11.64 and 12.09%, respectively. The n-3 to n-6 ratios of liver and fatty tissue of females were 1.61 and 0.95, respectively, whereas in male fish these were 1.31 and 1.05, respectively. Results of this study indicated that the liver and fatty tissues of patin catfish are suitable sources of fish oil specifically due to the presence of monounsaturated and n-3 polyunsaturated fatty acids.
    Keywords: Biology ; Fisheries
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  • 50
    Publication Date: 2018-05-16
    Description: The movement parameters of yellow fin tuna schools were analyzed by means of scanning sonar in tuna purse seine capture situations in the Oman Sea in June 2010. There was significant difference in swimming speed and radial swimming direction between the escaped and captured schools. In escaped cases, the fish schools swam faster with mostly horizontal avoidance behavior to the sound stimuli from the surrounding vessel and escaped capture under the sinking net at last. The swimming speed of the schools in two occasions was correlated to the vessel’s speed. Some alternatives of new constructions of the nets with regard to the sinking speed are discussed that may reduce the potential problem of escape capture during purse seining process.
    Keywords: Biology ; Fisheries
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  • 51
    Publication Date: 2018-05-16
    Description: Body composition and fatty acid profile of the body tissue of Caspian kutum (Rutilus frisii kutum) fish larvae were determined from fertilized egg to 50 days post hatching (dph). Feeding with rotifer started from day 3 to day 7 thereafter they were fed with dry food until the end of the experiment. The changes observed in lipid content and the decrease in lipid levels during larval ontogeny reflect the utilization and mobilization of lipids during both embryogenesis and larvae development. During this study, palmitic and stearic acids were the most abundant saturated fatty acid (SAFA). In kutum larvae, no utilization of palmitic and stearic acids was observed until 20 dph. It thereafter was utilized as an energy source. Oleic and palmitoleic cacids were the predominant monounsaturated fatty acid (MUFA). Oleic and palmitoleic acids utilized until 10 and 25 dph, respectively thereafter they increased. DHA, EPA and ARA were the major polyunsaturated fatty acids (PUFA). The decrease in levels of DHA and EPA denotes their utilization as an energy substrate by kutum larvae. ARA decreased during larval ontogeny, reflecting dietary values. With regard to reared kutum larvae in fresh water and the low levels of HUFA in larval diet, it can be said that kutum larvae possibly are quite capable of elongating and desaturating C18 to C20 PUFA. In case of proximate analysis, the percentage of body protein and ash increased trend during ontogeny while the percentage of body lipid and moisture decreased trend during larval growth.
    Keywords: Biology ; Fisheries
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  • 52
    Publication Date: 2018-05-16
    Description: It has been found that appropriate probiotic applications increased growth performance and disease resistance in shrimp. Bacillus subtilis has been suggested as a potent probiotic in improving growth performance and enhancing immune response in white shrimp, Litopenaeus vannamei. The aim of this work was to evaluate the possible effect of B. subtilis administration on the meat fatty acid profile of white shrimp, L. vannamei. Two groups of shrimps received B. subtilis strains L10 and G1 from the B. subtilis-supplemented feed (10^5 and 10^8 CFU g^-1) while two other groups received it from the rearing water (10^5 and 10^8 CFU ml^-1). One group received no B. subtilis and served as control. According to the results, there was no significant difference between the muscle fatty acid profiles of shrimps administrated by probiotic and control group. This study showed that B. subtilis administration, in either diets or water, did not have any negative effect on fatty acid profiles of L. vannamei meat.
    Keywords: Aquaculture ; Biology ; Fisheries
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  • 53
    Publication Date: 2018-05-16
    Description: Organoleptic characteristcs and eating acceptability of different processed fresh water clam (Galatea paradoxa) from Bayelsa state, Nigeria was evaluated. One hundred and fourteen (114) samples of clam (Galatea paradoxa) used for the processing experiment were obtained from Amassoma market. All samples were processed traditionally viz: smoked-dried, cooked with banga sludge and fried respectively. Thirty six (36) member taste panel were randomly selected to evaluate the organoleptic characteristics of the samples. Acceptibility of product was scored on a 6-point hedonic scale. The highest ratings of organoleptic characteristics were recorded for fresh water clam samples prepared by frying (5.24 ~c 0.54) while the least (4.47 ~c 0.27) was recorded for samples that were prepared by cooking with water (P<0.05). The results revealed that males had a preference for fried clam product while females had equal preference for clams fried and cooked in palm kernel sludge. The highest acceptability (88.89%) was observed in the samples that were subjected to frying method, while the least (80.56%) was recorded for samples that were smoked-dried. More research should be geared towards packaging these products for export.
    Keywords: Fisheries
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  • 54
    Publication Date: 2018-05-16
    Description: Six (6) Samples of commercially important freshwater fishes: Clarias anguillaris, Lates niloticus, Hemisynodontis membranaceus, Oreochromis niloticus, Citharinus cithrrus and Momyrus rume from Lake Kainji, Nigeria were analyzed during the dry and wet seasons to assess the variation in nutrient and mineral contents using standard procedures in wet weight basis. Result showed high nutrient content in both dry and wet samples. Mineral content were generally low except for Na and Ca among all the samples. Pb and Cd were not detected. Statistical analysis (P>0.05) showed no significant difference between dry and wet samples.
    Keywords: Fisheries
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  • 55
    Publication Date: 2018-05-16
    Description: This study evaluated the economy, and efficiency of the rice husk and wood shavings as alternative source of energy for smoking fish. Thirty six specimens of Tilapia zilli weighing between 60 - 100g each were obtained from fresh fish market in Minna, Niger State. Twelve specimens each were smoked with fuel wood, rice husk and wood shavings respectively in a Kanji portable smoking kiln with fuel wood serving as the standard. Fuel economy, efficiency, proximate composition and sensory quality evaluation were conducted. The sensory quality examination was evaluated by a panel of fifteen volunteers. The results showed that, the products were not significantly different (p>0.05) in moisture content, lipid and ash, while there was significant difference in the percentage crude protein (p<0.05). There was no significant difference in the colour, texture and overall acceptability (p>0.05), while there was significant difference (p< 0.05) in the appearance, taste and flavour. The total colony forming unit (log 10 CFU/g) of smoked fish ranged between 1.16 ~c 9.41 -2.20 ~c 4.36 and 5.10 ~c 6.66 - 5.40 ~c 6.00 for the first week and eight (8) weeks respectively. There was significant difference between the microbial load of week 1 and 8. The microbial load was relatively higher in the products of rice husk in the first week, while it was relatively greater in the products of wood shavings in the 8thweek. Cost analysis revealed that 1.144 kg; 3.0kg and 0.786kg of fuel wood, rice husk and wood shavings were used per kg of fresh fish at N150.00, N50.00 and N50.00 respectively. Smoking durations were 4 hrs 30 minutes, 6hrs 50 minutes and 5 hrs 52 minutes for fuel wood, rice and wood shavings respectively.
    Keywords: Fisheries
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  • 56
    Publication Date: 2018-05-16
    Description: Study was conducted on the reproductive efficiency of Chrysichthys nigrodigitatus of the Cross River. The objective was to determine the influence of age on eggs size and fecundity. Forty four females of Chrysichthys nigrodigitatus were sampled from April, 2011 to March, 2012. Fecundity and eggs size were measured in relation to fish size. The relationship between egg size and fish size produced a parabolic curve. This implies that younger fish and older fish were less efficient in terms of eggs size and quality while the middle aged fishes were more efficient in terms of eggs size and quality. Similarly, there was an inverse curvilinear relationship between number of eggs per unit weight and somatic weight of the fish. Younger fish are less efficient because of the physiology of growth, while the older fishes are less efficient because of reproductive senescence. Management strategy for the stock therefore requires the conservation of the middle aged individuals for increase in reproduction. Also in aquaculture the middle aged class should be used as broodstock for excellent results.
    Keywords: Ecology ; Fisheries
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  • 57
    Publication Date: 2018-05-16
    Description: Biotechnology per se is not a panacea for the world's problems of hunger and poverty. However, genetic engineering in particular, offers outstanding potentials to increase the efficiency of animal improvement. Thus, biotechnology could enhance global food production and availability in a sustainable way. Case studies from Egypt and India also demonstrate that highly immune genetically modified fishes, transgenic fishes, chromosome engineering and gene banking are very appropriate for fish farmers and consumers in developing countries. As the entire technology can be packaged into the germ cells of fish, it can easily be integrated into traditional small-holder fish farming systems. Except for a few innovative transfer projects, though, the application of biotechnology until now remains concentrated in the industrialized world. Combined with insufficient own scientific and regulatory capacities, the increasing privatization of international aquacultural and fisheries research and the strengthening of intellectual property rights complicate the access of developing countries to biotechnology. Profound constitutional adjustments are therefore essential to ensure that biotechnology does not bypass the poor.
    Keywords: Aquaculture ; Fisheries
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  • 58
    Publication Date: 2018-05-16
    Description: Energy is one of the main concerns for the future development of any nation. It is by far the largest merchandise in the world and an enormous amount of it is extracted, distributed, converted and consumed in our global society daily .One major problem regarding agricultural produce is related to the product storage in the harvesting season, and identifying an alternative to marketing fresh produce. A useful option is to prevent wastage of produce by drying, using solar energy. In this regard, solar dryer for domestic as welI as industrial usage could be an effective alternative of saving conventional energy. Utilization of solar thermal energy through solar dryer is relatively in a nascent state in our country. This paper gives a description of the efforts made under several researches to design and develop some types of solar dryers.
    Keywords: Fisheries ; Environment
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  • 59
    Publication Date: 2018-05-16
    Description: Effect of feeding on linseed oil (LO)-enriched Artemia was investigated on growth, survival and stress resistance of tiger barb (Puntius tetrazona) larvae. Larvae were fed by LO-enriched (2.5, 5 and 7.5%) as well as non-enriched Artemia nauplii for 14 d, followed by 14 d feeding on non-enriched Artemia. Fish fed on enriched nauplii showed significant increase in growth performance at both 14th and 28th d. Also, fish fed on enriched Artemia, especially those fed on 7.5% LO, showed greater resistance in response to osmotic and hypoxia stress at 28th d. The results suggest that LO enriched Artemia nauplii are capable to promote growth and stress response in tiger barb larvae.
    Keywords: Biology ; Fisheries
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  • 60
    Publication Date: 2018-05-16
    Description: Twenty four farmed great sturgeon, Huso huso (including 8 males and 16 females) over 6 years old were used to develop a method for determination of sex and maturity stages. Seasonal gonadal tissue and blood samples were collected from farmed great sturgeon for three years. The sex and stages of maturity were determined by histology and laparoscopy at the beginning and end of experiment. Plasma sex steroid hormone levels [testosterone (T), 17β-estradiol (E2) and progesterone (P)] were measured by radioimmunoassay, and plasma calcium ion levels were measured by spectrophotometer. Mean concentrations of testosterone, progesterone and estradiol in blood plasma of H. huso at maturity stages II, III and IV were 10.86±1.63, 54.14±3.1, 112.41±7.4; 0.84±0.12, 15.66±2.18, 50.75±3.63 ng/ml in males and 9.0±1.39, 6.51± 0.64, 2.95±2.29, 5.45±0.29, 9.47±0.97 and 4.15±0.7 ng/ml in females, respectively. Testosterone and estradiol levels showed significant differences at various stages. Calcium level at stages II, III and IV of sexual maturity in females (8.05 ± 0.09, 10.4 ± 0.34 and 9.6 ± 0.6 mg/dl) was more than males (7.73 ± 0.16, 8.58 ± 0.13 and 8.76 ± 0.11 mg/dl). Results showed that steroid hormone concentration and calcium level of blood plasma in males and females vary between different stages of sexual maturity. Therefore it can be used to determine the stages of sexual maturity in farmed H. huso.
    Keywords: Aquaculture ; Biology ; Fisheries
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  • 61
    Publication Date: 2018-05-16
    Description: A study on threats to fish species conservation in Echara River, Nigeria was carried out from September 2009 to February 2011 to generate inferential data for Fisheries policy formulations to assess the potential of the Fishery to alleviate malnutrition among the poor in the rural communities, and use of the living resources for teaching and research. A total number of 709 fishes comprising of Fin-fishes and shell-fishes belonging to 13 families, 19 genera and 40 species were caught in 216 fishing efforts, at 10 days interval using hooks and lines (size 13), cast nets, gill nets and traps of mesh sizes of 50mm, 75mm and l00mm respectively. Fish identification was done using taxonomic keys. Evaluation of fishing methods of the Artisans within the basin was by visual survey and the use of structured questionnaires. It was observed that during the dry season, 55% of artisanal Fishers used obnoxious methods to catch fish, ranging from chemical toxicants (14%), unselective Fishing gears (35%) and direct draining (6%). It was concluded that there is an urgent need for monitoring the impacts of human activities on freshwater systems and to evolve appropriate implementable management strategies, backed up by political will to check anthropogenic impacts that have deleterious effects on the fishery.
    Keywords: Ecology ; Fisheries
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  • 62
    Publication Date: 2018-05-16
    Description: Retort pouch as a packaging material for varieties of food items such as fish, vegetables, fruits and food crops was highlighted. Materials required for the processing of pouches were listed and the methodology of production discussed. The paper provided insight for investors to invest in the technology of pouching as a means of engaging unemployed youths in Nigeria.
    Keywords: Fisheries
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  • 63
    Publication Date: 2018-05-16
    Description: Elongation (cm) and breaking-load (kgf) effects on artisanal Polyvinyl-Alcohol (PVA) synthetic twine of diameters 4mm, 6mm, 8mm and I0mm soaked in fresh (0.4ppt), brackish (25ppt) and marine (37ppt) waters for 112 days were investigated. Chemical (burning) test was carried out to identify the experimental white twine as PVA, among other six locally synthetic twines (Klust, 1973). A tensile-strength gauge machine (0-200kg) was used to test the mechanical strength properties of PVA twine diameters in dry (control) and wet states. Results indicated that elongation and breaking-load of the specimens were significantly (P<0.05) influenced by R- Tex. Elongation and breaking-load were observed to be highest in dry twine 10mm with means of 20.75a ~c 1.05 and 140.00a ~c 5.37 respectively, higher in twine 10mm (with means of 20.40b ~c 3.50 and 131.75b ~c 5.l0 respectively) soaked in freshwater and lowest in twine 4mm (means of 1 4.83fg ~c 0.31 and 33.70h ~c 1.00 respectively) soaked in marine water. Twines of the same diameter (l0mm, 8mm, 6mm & 4mm) soaked in fresh water (0.7ppt) has highest significant (p<0.05) elongation and breaking load than those soaked in brackish (0.25ppt) and marine water respectively. The thicker the PVA twine diameter, the higher the significant (p<0.05) elongation and breaking load, which could lead to increased mesh sizes of fishing nets constructed from such twines. Fishermen are therefore encouraged to air-dry their fishing nets or gears when not in used to extend the shelf-life.
    Keywords: Fisheries
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  • 64
    Publication Date: 2018-05-16
    Description: Overcoming Poverty in Nigeria is one of the fundamental challenges facing the country today. The study was conducted to assess the socio-economic status of fisher folks in Yuna Adopted Village Borgu Local Government Area of Niger State. One hundred respondents (65 male and 35 female) were purposively selected from four registered groups in the Village. Frequencies and Percentages were used to arrange, summarize and present the findings of this study. Majority of the male respondents fell within the range of 30-49 years, while female respondents range from 40-49 and 60-69 years. The distribution of respondents based on educational attainment shows that 92.3% male and 100% female had Quranic education. Majority of the respondents (both male and female) lives in mud with thatched roof houses and do not own radio and television. Similarly the highest proportion of male respondents generated mostly income of N111,000 and N6,000 - N10,000, while female respondents earned between Nll,000 - N30,000 and N6,000-N10,000 only. The technologies awareness by respondents include fish farming, V-bottom boat, Solar tent dryer and trammel net, only fish farming was adopted by respondents. The major constraints to Agricultural production were identified and suggestions was made on how to overcome the constraints.
    Keywords: Fisheries ; Sociology
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  • 65
    Publication Date: 2018-05-16
    Description: The effects of diesel-oil spillage of fresh (0.4ppt), brackish (25ppt) and marine (37ppt) waters on elongation (cm) and breaking load (kgf) of artisanal PVA synthetic twine of varied diameter (4mm, 6mm, 8mm and 10mm) soaked for 16 weeks was studied. Chemical (solubility) test was carried out to identify the experimental twine as PVA among other synthetic twines. The elongation (cm) and breaking load (kgt) of PVA twine diameters were tested by tensile-strength gauge machine (0-200kg) and was carried out in unpolluted (control) and polluted states (spillage level) at 0%, 20%, 40%, 60%, 80% and 100% diesel-oil concentrations of different water salinity. Factorial statistics was used to analyze the treatments; twine (at four levels), water salinity (at three levels) and concentrations (at six levels). This implies 4 by 3 by 6, replicated in four places (288 treatments). Results indicated that elongation (cm) and breaking load (kg) of the specimens were significantly (P<0.05) influenced by twine thickness. Twine l0mm soaked in 3.0 litres of unpolluted freshwater had significant (p<0.5) correlation coefficient r,0.927 and lowest r- value of 0.499 was obtained in twine 4mm soaked in 100% diesel-oil concentration. Significant (P <0.05) relationships were observed between the correlation coefficient r = 0.531-0.927 for unpolluted and r = 0.499-0.592 for polluted tests. The study revealed that diesel-oil spillage had negative effects on the quality of twines. The thicker the PVA twine diameters (10, 8, 6 and 4mm) at lowered (0%, 20%, 40%,60%,80% & 100%) diesel-oil spillage of fresh (0.4ppt), Brackish (25ppt) and Marine (37ppt) waters respectively, the higher the significant (P<0.05) elongation (cm) and breaking load (kgt) were evaluated in most cases.
    Keywords: Conservation ; Fisheries
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  • 66
    Publication Date: 2018-05-16
    Description: This study examined the demand analysis for fresh fish in Abeokuta metropolis of Ogun State, Nigeria. Data were collected with the aid of structured interview schedules and direct interview to elicit information from 150 fresh fish consumers randomly selected from within the locality of three major fresh fish markets (Olomore, Itoku, and Kuto). The data collected were analyzed using descriptive statistics and regression analysis which revealed that most of the fresh fish consumers (95.9%) were literates with mean household size of 5 persons. Also, 70% of the respondents are female out of which 71.3% are married, 52.8% were in the active age of 31-40 years old, and 70% are Yoruba speakers. Few (33.3%) of the high income earners spends the least income expenditure on fresh fish while 67.7% of the low income earners spends on frozen fish. It was evident from the study that the quantity of fish demanded increases as household size, income and age increases. The regression results shows that 36.8% of the total variation in the demand for fresh fish are variables while the remaining 63.2% were not explained by variables with R value of 0.368 according to the equation. Based on the findings, it was discovered that many people preferred fresh fish to frozen fish; efforts should be made to discourage importation of frozen fish and divert the huge amount spent on importation on expansion of aquaculture industry for the provision of more fresh fish for the consumers.
    Keywords: Fisheries ; Aquaculture
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  • 67
    Publication Date: 2018-05-16
    Description: Fish is one of the most nutritious diet on earth, and contributes a considerable proportion of its protein to the Nigerian populace. Fifty-four specimens composing of six samples from each species, were analyzed in frozen and smoked states, monthly. Each set of six specimens were cut into two equal parts and randomly re-arranged into two groups. One group was smoked while the other was preserved in the freezer (at-2~'C) for 5 days. The highest moisture content was observed in frozen samples of Mormyrops deliciosus thus: (77.14 ~c 11.05%). Smoked O. niloticus had the highest protein content (26.79 ~c 0.74%) while the least was observed in frozen Mormyrops deliciosus (13.37 ~c 2.57%). Smoked samples of Oreochromis niloticus recorded the highest fat content accounting for a value of (25.97 ~c 0.51 %) while the least was observed in frozen Mormyrops deliciosus (7.97 ~c 0.45%). It could be concluded that while frozen samples loosed nutrient, smoked ones gained nutrients in all three species. The study recommends that fish be consumed in their smoked state, in preference to frozen ones, in response to higher nutritive value. Oreochromis niloticus which recorded the highest nutritive value in crude protein content, should be consumed more, followed by Labeo coubie and Mormyrops deliciosus in that order.
    Keywords: Fisheries
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  • 68