ALBERT

Notes: Participation at the local level is an important factor in determining the success of programmes developed to achieve sustainable development. This paper is concerned with debates over the role of the individual citizen in relation to that participatory process. In particular, it focuses on the UK Governments’ citizens environmental initiative ‘Going for Green’ (GFG). Through this initiative a five-point Green Code was developed to assist in the delivery of its sustainable development message to the general public. The initiative's overall approach to participation was based on an assumption that the primary barrier to translating environmental concern into local action was a lack of information, and that individuals would respond to messages in a similar way. As a research strategy, the case study was used to evaluate how the initiatives’ pilot Sustainable Communities Project was implemented in two comparative geographical communities in Merthyr Tydfil (South Wales). Research findings from this study have demonstrated that the case study was invaluable in terms of understanding the participatory process and experiences of broad a range of community stakeholders. Promoting a single model of participation, GFG was found to restrict the participatory process in terms of who was encouraged to participate, the scope of their participation, and those outcomes that could be achieved. This paper concludes that if significant progress is to be made in relation to achieving sustainable development, the role of the individual citizen needs to be extended beyond that of a consumer of the environment, and involve active participation in a process that is based on collective action.

Notes: This paper examines the influences of question wording on consumers’ levels of support for genetically modified organisms (GMOs) in food products. Pairs of questions, offering varied amounts of information on the benefits and risks of GMOs, are posed to consumers in a specific geographic area (Vermont, USA) to ascertain the factors that impact on levels of support for this technology. A multivariate analysis is conducted to examine how knowledge, attitudes, and behavioural intentions affect changes in levels of support. The findings suggest that consumers’ levels of support do vary based on question wording. It is further found that knowledge and behavioural intentions play a consistently significant role in influencing change in support for GMOs. Implications for both consumer advocacy groups and industry groups are discussed.

Notes: To date, few studies have empirically examined specific values with respect to the global teenager hypothesis. In testing the global teenager hypothesis, this study investigates similarities and differences in materialism among 14- to 17-year olds in China, Japan and the USA. Significant differences were found between respondents from the three nations for materialism and discretionary spending power. Discretionary spending power had a significant effect on materialism across nations. In addition, evidence supports cross-national differences in the psychological structure of the materialism construct. While personal gain and social gain explain two materialism dimensions for the Japanese and American samples, factor analysis results suggest materialism may have alternative conceptual underpinnings in China. The findings of this study generally fail to support the global teenager hypothesis as it relates to the value of materialism.

Notes: Consumerism is part of living in the contemporary post-modern world. It is claimed that schools and consumer education have a rather marginal impact on the consumer behaviour of young people. This qualitative study explores adolescents’ ways of consuming in three different worlds: home, school and peer groups. The aim is to understand how the adolescents experience border crossings between these worlds. What do they think about consumerism and consumer education? Finally, the pedagogical challenges of consumer education are discussed. The qualitative data was collected through mind maps, written questionnaires and semi-structured group interviews. Qualitative content analysis was used to analyse the data. The data was collected from 59 teens (between 14 and 15 years of age) from Vantaa, Finland. According to the results, the adolescents’ way of consuming in each world differs from each other. However, border crossings occur with natural strategies and smooth transitions. The adolescents feel that ‘real’ consumerism does not begin until adulthood. Then, it is time to act like responsible consumers. Their motivation to study consumer issues at school is poor, because they feel the substance of consumer education not corresponding to their lives. Because of this, consumer education needs pedagogical renovation based on the needs of the adolescents and the special features of their consumerism.

Notes: This article examines how young Finns represent their consumer identity through narratives. Young consumers are easily seen as careless spenders and selfish hedonists in the contemporary consumer society. However, an empirical approach is required in order to find out whether this generation of young Finnish consumers is one of ‘raving hedonists’ or ‘ultimate materialists’, as their peers are often presented in public discussion in many western societies. The empirical data was collected in five upper secondary schools between the end of November 2001 and the beginning of January 2002. These schools are located in five different districts in Finland, varying from metropolitan to rural areas. The study focused on students aged 16–19 years and used essay writing as the method for collecting qualitative data. The data thus consists of 159 life stories as a consumer written by young Finnish people. Qualitative research methods, such as narrative analysis, were used in this study. It is argued that Finnish young people are representing their identities as consumers through a combination of various levels of consumer discourses besides hedonism and squandering: rationality and economizing are an essential part of their consumer identities. Some youngsters also present themselves as responsible consumers including ecological and ethical choices as part of their narrative. The way these youngsters combine discourses gives evidence of the various features of the present-day young consumer. It is also suggested that their consumer identity develops and changes with age. Young people describe their identity changing through a hedonist/squanderer discourse to a rational and economical one or vice versa. They also combine hedonist, rational, economical and responsible discourses simultaneously.

Notes: Laboratory experiments were performed with cultured and wild juvenile winter flounder Pseudopleuronectes americanus to evaluate differences in behaviour and adaptation affecting post-release vulnerability to predation. Studies revealed that the cryptic abilities of cultured winter flounder increased over time. Sediment-naïve, cultured fish required a minimum of 2 days to improve their burying skills and at least 90 days for colour adaptation to match the sediment. Cultured winter flounder selected sediments consisting of small grains and colours matching their own pigment. Cultured winter flounder, regardless of their colour, were significantly more vulnerable to predation by birds. Additionally, cultured fish reacted differently than wild winter flounder when exposed to cues from a potential predator.

Notes: More than 800 000 reared juvenile turbot Psetta maxima were released in Danish waters during the period 1990 to 2002, as part of a stock enhancement programme. Performance of the released fish has been investigated using a combination of surveys and experimental studies. A total of 1278 wild fish and 439 alizarine marked released fish were caught in 16 surveys from 1993 to 1997. Recaptures were made over a period of c. 2 years after release. Results of growth analysis and measurements of nutritional status (condition factor, liver index, liver dry matter and otolith residual mass) showed only minor differences between wild and released fish. Growth rates of wild and of released fish were comparable to fish kept in the laboratory at the same temperature (specific length growth rate c. 0·5% day−1 at 75–185 mm total length and 12·5° C). The results indicated sufficient food in the release area, but significant differences in growth and in nutritional status, between  years, were also observed. Nutritional status of both wild and released fish was comparable to fed fish in the experiments and significantly higher than in fish starved for  〉 1 week. The effects of the transport and release procedures used were examined by simulated releases in laboratory tanks. The fish were observed to be feeding and growing normally during the first week after simulated release, suggesting this species to be relatively robust and unaffected by the handling and release procedures.

Notes: Growth hormone (GH) was applied to Atlantic salmon Salmo salar parr (the pre-migratory freshwater life stage) to manipulate growth potential experimentally and to elucidate the effects on dominance status, actual growth, exploratory activity and home range. Experiments were conducted using seven groups of eight parr from May to September of two successive years. The fish were tagged with passive integrated transponders (PIT tags), tested for dominance, and then held in an enclosed section of a natural stream which was fitted with an array of PIT tag detectors to record space use at a definition of c. 2 m. Relationships between dominance rank, space use and growth were established over 2 weeks. The four lowest ranking fish in each group were then given a slow-release GH implant while the other fish received a placebo. The GH stimulated increase in fork length (LF) and mass and decrease in condition factor due to the relatively greater increase in LF. There was, however, an interaction between GH-stimulated increase in growth and season, with the hormone having an effect only during the early part of the summer. Regardless of treatment, fish that moved most around their home range grew fastest. Increased growth in GH-treated fish was associated with an increase in growth per unit movement, not increased total movement. This suggested that GH-treated fish increased their rate of short-distance (〈2 m) foraging movements. Overall, space use, measured in terms of home range size and time allocation throughout the range, did not vary consistently in response to application of GH. There was a strong correlation between the weighted centre of the home range (a measure of position within the enclosure) before and after treatment, irrespective of whether fish were given GH or a placebo. The study shows that when density is low relative to carrying capacity, GH stimulates increased dominance and growth in a near-natural environment without having measurable effects on space use at a definition of c. 2 m. The results are interpreted as suggesting that high dominance status gives no significant growth advantage in a highly competitive situation, but increases foraging rate when food is abundant. Increased foraging appears to result from local changes in time budgeting rather than variations in the extent of home range and larger-scale movements within it. Thus, in areas with declining wild Atlantic salmon populations where the habitat is unsaturated and food is abundant, introduced domestic Atlantic salmon may be competitively superior.

Notes: In comparison to barbel Barbus barbus in their natural, riverine environment, the growth performance of cultured barbel, following introduction into stillwater environments, was depressed when the extant stock density was above 500 kg ha−1 and common carp Cyprinus carpio were present.

Notes: Hatchery and wild juvenile populations of steelhead Oncorhynchus mykiss and coho salmon Oncorhynchus kisutch, in a small coastal watershed in central California, were sampled throughout the year in a stream and at a hatchery. Both species grew faster in captivity than in the wild. Hatchery fish of both species had elevated gill Na+, K+-ATPase activity, and thus were ready to enter sea water when planted during the wild fish migration. Downstream migrant trapping and stream surveys indicated that hatchery smolts went to sea soon after planting, consequently avoiding the effects of competition and predation that commonly occur when hatchery-bred juveniles are released. Adult steelhead were also sampled throughout the watershed. The return of hatchery steelhead was highly synchronized with that of wild steelhead, indicating that hatchery propagation had no adverse effects on the timing of the run. A disproportionate number of hatchery steelhead returned to the tributary where the hatchery was located, despite being planted throughout the watershed. Hatchery steelhead did not differ in mean age or size from wild steelhead. Observations of spawning indicated that hatchery and wild steelhead interbreed. Competition for mates or spawning substratum was rarely observed between hatchery and wild steelhead. Many of the problems commonly associated with artificial propagation can be avoided in small coastal watersheds when wild broodstock are used and fish are released as smolts.

Notes: Outbreeding depression was not detectable in observations of embryonic survival and of survival of smolts to adulthood relative to controls in coho salmon Oncorhynchus kisutch experimentally outbred over two generations by crossing fish from three widely separated populations. Survival in outbred coho salmon was not detectably less than that in second-generation hybrid controls or second-generation parental controls. Variation of embryonic survival was affected by the maternal source population and by individual females but not by the paternal source population or by individual males. Survival of smolts to adulthood at sea was greater in one second-generation control group than in two others, but survival in second-generation outbred groups was no less than in parental controls or hybrid controls.

Notes: The protected environment in culture permits fishes to reduce the proportion of energy normally channelled into the costs associated with competition for food, shelter and mates, avoidance of predators and counteracting parasites and diseases. The surplus energy so released is allocated to growth and reproduction, accelerating development through increased growth rate, earlier maturation and increased relative fecundity. Cultivators manipulate the rearing environment to remove seasonal variation in availability of resources, so that the fishes grow and develop through otherwise unproductive seasons. Such environmental manipulations exaggerate the basic accelerative effects. Since maturation deflects energy from growth, farmers also manipulate the fishes nutritionally, physiologically, hormonally and genetically to postpone maturation. As environmental regulators determine sex in many fish species, environmental manipulation in culture may have unintended effects on sex ratios. Mortality in culture should be very low, but survival of fishes released from culture is rarely as high as that of wild conspecifics. Finally, while short life-cycles and simplified population age-structures permit high rates of production in farms, they lead to ecological instability when the fishes are cultured for support of wild populations.

Notes: Accidental escapees from aquacultural facilities are an ongoing problem facing scientists, conservationists, policy makers and naturalists throughout the world. The topmouth gudgeon Pseudorasbora parva, a small cyprinid native to Southeast Asia, was introduced to Romanian waters in 1960 via the aquaculture trade and has since spread throughout Europe. It first appeared in England in an ornamental fish farm near Romsey in Hampshire. The aim of the present study was to quantify the dispersal of this potentially highly invasive species from an ornamental fish farm into the wild. In order to measure the dispersal of escapees, intensive electrofishing surveys were carried out between June and September 2003 in the catchment downstream of the fish farm. The distribution of topmouth gudgeon in the catchment was found to be limited and patchy. The presence of small individuals suggests that the species has successfully established itself in the wild, but this remains to be confirmed. The results were examined in light of invasion theory principles of biological resistance and ecological fitness.

Notes: Nase Chondrostoma nasus L., once one of the most common fish species in the upper reaches of central European rivers, is now considered endangered throughout its natural range. Since 2000 the Department of Ichthyobiology and Fisheries, Warsaw Agricultural University, has co-operated with the Polish Anglers Association in Krosno to study the effects of river restocking with pond-farmed nase juveniles. The experiment is carried out on Wislok River, where nase was very twenty years ago but has now completely disappeared. Selected parts of the river are stocked with tagged, one-summer and 1 year-old juveniles. Changes in nase occurrence, and their growth and foraging behaviour have been analysed.

Notes: Gilthead seabream Sparus aurata and European sea bass Dicentrarchus labrax, are two important species in Mediterranean aquaculture. In the wild, their juveniles occur in brackish areas such as lagoons and river deltas. Even though the juveniles seem to favour brackish environments, low salinity incurs an energy cost for osmoregulation. This paper presents the results of a series of laboratory experiments exploring the effects of salinity on growth, feeding, food conversion, survival and maintenance energy requirements of wild-caught juveniles. The fish were kept in the laboratory, divided in groups of 20 in small tanks of 50 l each, and supplied with biologically filtered seawater of four salinity levels (8, 18, 28‰ and natural seawater) and fixed temperature (20 ± 1·4° C). The fish were fed pelleted feed throughout the experiment. Both species showed great similarity in their responses to lower salinities. Satiation time for both species increased with decreasing salinity, while maintenance requirements (required daily ration and energy) increased as with increasing salinity. Growth and feed conversion is highest for salinities around 28‰ and lower for salinities above and below. Both species share common physiological features, and intermediate salinities are optimal for their performance in nature and in captivity.

Notes: The winter flounder is an in-shore flatfish living in shallow waters on the east coast of North America from Labrador to Georgia. In the St Lawrence estuary, the reproductive season is May and June. Our objective was to test the effects of winter-spring photoperiod and temperature conditions on the timing of sexual maturation in both males and females. Groups (16 animals each) of winter flounder breeders were maintained from mid-January to mid-May under five different experimental conditions: (1) natural photoperiod and temperature conditions; (2) natural photoperiod, 6° C; (3) 15L : 9D, natural temperature conditions; (4) 15L : 9D, 6° C; (5) accelerated photoperiod increase from winter to spring conditions, 6° C. Natural photoperiod and temperature conditions correspond to a gradual increase in light period from 8L : 16D (January) to 15L : 9D (May) and in temperature from −1° C (January to April) to 6° C (May). GSI and condition factor did not differ among the treatments (P 〉 0·05). In males, milt production occurred simultaneously in the different treatments and histological examination did not indicate any significant effect of either photoperiod or temperature on testes development. In females, seven stages of oocyte development were observed. Both the number of oocytes at the cortical alveoli stage and number of atretic oocytes increased at 6° C (warm temperature conditions). Overall, neither photoperiod nor temperature modified the reproductive period. Warm winter-spring temperature conditions, however, may decrease egg numbers and egg quality.

Notes: In spring 2001 and 2002 a small stream was stocked with tagged hatchery-reared yearling brown trout (Salmo trutta), in order to study their influence on the resident brown trout population. The stream was separated into six sections: two sections without stocking, two sections where stocking doubled the trout population and two sections where the fish population was quadrupled. The working hypothesis was that due to food limitation (competition) growth of the wild fish will be negatively influenced by stocking, and wild fish will be displaced by the (possibly more aggressive) hatchery fish. Surprisingly, growth rate of wild and stocked fish of the same age was similar and independent of stocking density. Two main reasons may be responsible for this finding: only a low percentage of the stocked fish remained in the stream, and food was not limited during summer. Only 12–19% of the stocked fish were recaptured after six months, in contrats to 40–70% of one-year old and up to 100% of older wild trout. The wild fish were not displaced by hatchery-reared fish: During summer the wild fish remained more or less stationary, whereas most of the stocked trout had left their release site. The results indicate that in a natural stream stocking of hatchery reared brown trout does not influence negatively growth and movement of the wild fish independent of stocking density.

Notes: Seabass (Dicentrarchus labrax) swimming activity was compared between natural environments and aquaculture facilities. Behaviour under natural conditions was assessed in a saltmarsh pond (250 m2, 18 × 14 × 0·8 m) using acoustic telemetry. From several surveys, we documented the diel activity rhythm and demonstrated group effects on swimming patterns and amplitudes by comparing activity of solitary fish with that of a fish living in a group of 60. Consequences of weather variability were also analysed and revealed a high sensitivity of fish to atmospheric conditions for both swimming and demand-feeding behaviour. Behaviour in fish tanks was also studied using acoustic telemetry, as part of the EUREKA EU1 960 ‘Aqua-Maki 2’ project investigating aspects of fish culture in re-circulating tanks under high density. A re-circulating hexagonal tank (5·4 × 5·4 m, 1·8 m depth, 48 m3) was equipped with positioning and demand-feeding systems, oxygen and temperature probes. Initial density was 50 kg m3 in March and rose to 90 kg m3 at the end of the experiment in May. During this period, the movements of nine fish were continuously recorded for 24 h each, reaching a total of six 24 h episode at eight days interval. Swimming activity was analysed in terms of activity rhythms and space occupation specially around feeding events. The two data set and main results will be presented and compared to assess seabass behavioural plasticity and sensitivity to husbandry conditions.

Notes: Anecdotal and empirical evidence exists for substantial (up to 40%) declines in growth among Oreochromis populations domesticated in both large and small-scale fish farms in Africa. These declines are at least partly attributable to poor genetic management, including inadvertent selection, inbreeding, bottle-necks and founder effects. Due to restricted cash flow and investment capital, genetic management and selective breeding for the improvement of domesticate populations are difficult for small-scale farmers, but feasible on larger-scale farms. In managing domesticated gene pools, feral populations can serve as a broodstock reservoir, making the use of indigenous species advantageous. A development model of large-scale hatcheries producing selected lines of sex-reversed, indigenous tilapia for sale to smaller-scale farmers is proposed as a solution to the problems of poor genetic management in African aquaculture.

Notes: Stock enhancement is the main source of Acipenser gueldenstaedtii and A. stellatus recruitment in the Sea of Azov, where up to 30 million juveniles have been released in recent years. The hatchery production strategy aimed solely to produce and release the largest possible number of juveniles, utilizing only the most mature broodfish of the spring spawning run. Although monitoring of age, mass and physiological conditions of the broodstock during the period of hatchery breeding did not show significant changes, the spawning run was dramatically shortened from several months to just 15 days, and includes only fish with advanced gonadal maturity. Conservation of the Azov Sea species and their unique spawning ecotypes is currently supported by the Federal Living Gene Bank, which maintains over 9000 adults of eight endangered species. This paper summarizes the results of comparative analysis of biological characteristics such as growth, age of the first sexual maturation, relative fecundity, and morphological and physiological indices in wild and cultured specimens of different species and intraspecific groups of sturgeons. We conclude that there is a need for developing better hatchery technologies to maintain diversity of the stocks, through breeding protocols that maximize the genetic diversity of offspring based on evaluation of parentage and relatedness in farmed stocks by microsatellite loci.

Notes: Ide Leuciscus idus L. is a riverine cyprinid commonly produced as a subsidiary species in polyculture with common carp in Poland. In many cases production of restocking material is based on farm-reared broodstock. The aim of the paper is to study possible domestication effects on female reproductive parameters in ide following long-term pond cultivation. Three groups of fish were analysed: group (1) consisted of fish cultivated in carp ponds for three generations; group (2) consisted of fish caught as wild one-year-olds in rivers and kept in ponds until till sexual maturation (first pond-reared generation) and group (3) consisted of wild ide females caught at spawning sites just before natural spawning. All fish originated from the Vistula River in central Poland. Fish were stimulated with Hungarian synthetic hormone analogue (Ovopel). Body length and mass, individual fecundity and egg size were measured during spawning, and egg survival was assessed at the eyed ova stage.

Notes: Domestication has been shown to have an effect on morphology and behaviour of Atlantic salmon (Salmo salar). We compared swimming costs of three groups of juvenile Atlantic salmon subject to different levels of domestication: (1) wild fish; (2) first generation farmed fish origination from wild genitors; and (2) seventh generation farmed fish originating from Norwegian aquaculture stocks. We assessed swimming costs under two types of turbulent flow (one mean flow velocity of 23 cm s−1 and two standard deviations of flow velocity of 5 and 8 cm s−1). Respirometry experiments were conducted with fish in a mass range of 5–15 g wet at a water temperature of 15° C. Our results confirm (1) that net swimming costs are affected by different levels of turbulence such that, for a given mean flow velocity, fish spent 1·5-times more energy as turbulence increased, (2) that domesticated fish differed in their morphology (having deeper bodies and smaller fins) and in their net swimming costs (being up to 30·3% higher than for wild fish) and (3) that swimming cost models developed for farmed fish may be also be applied to wild fish in turbulent environments.

Notes: The Arctic charr of Lake Saimaa are the most endangered fish population in Finland, and reintroduction programs have been unsuccessful. Low success of reintroduction programs has drawn attention to behavioural properties of hatcheryreared fish. Mortality due to predation often is a principal cause of failure. Antipredator behaviour may degenerate rapidly under hatchery conditions due to (i) reduced genetic variation in antipredator behaviour and/or (ii) selection that would favour bold and fast growing individuals and disfavour predator awareness supposedly associated with slow growth. To test the relative importance of these two factors we first analysed the amount of variation in innate antipredator responses between and within families of hatchery-bred Arctic charr of the Lake Saimaa stock. We then tested whether fast growing individuals would show reduced responses to chemical cues from their natural predators compared to their slow growing counterparts. Based on the results we propose procedures for maintaining and improving antipredator skills of hatchery-reared salmonids.

Notes: Fish show a tremendous diversity in patterns of reproductive investment and in associated breeding systems (i.e. parental care and sexual selection, including the number of mates obtained by both sexes and the manner in which they are obtained through competition for mates and resources, courtship, and mate choice). These patterns play an integral role in shaping the evolution of populations and their dynamics, and thus changes in these patterns necessarily affect population viability. Artificial culture of fish in hatcheries, net-pens and gene banks almost invariably disrupts the natural breeding system and alters fitness-related traits. The implications, both genetic and ecological, of the intentional and unintentional release of these fish for wild populations are largely dependent on what occurs during breeding and its subsequent effects on offspring performance. Our findings and those of others have indicated that gene flow from cultured to wild populations is frequently impeded by altered breeding behaviour and biased by sex and life history strategy. Moreover, breeding affects subsequent offspring performance through not only genetic (e.g., disruption of co-adapted gene complexes, MHC non-assortative mating), but also non-genetic maternal effects (e.g., breeding time and location, egg size). While significant advances have been made in the last decade, our understanding of the reproductive ecology of cultured fish in the wild remains somewhat in its infancy. Such study continues to be integral in enlightening our management of cultured fishes in the wild, and more broadly for increasing our understanding of fish breeding systems and thus population dynamics.

Notes: Increasing concern has been expressed about the genetic effects of cultured salmonid fishes on natural populations. Avoidance of extreme negative outcomes was one reason for the establishment of a genetic management policy for the State of Alaska. However, domestication within the hatchery may still cause divergence from the wild donor population. This divergence could potentially lead to adverse impacts on wild stocks through straying and introgression. This study examines potential domestication in two Alaskan chinook salmon stocks. The Little Port Walter (LPW) Hatchery Chickamin River stock resulted from a small collection of wild broodstock in 1976. The LPW Unuk stock was founded with a larger number of individuals in 1976 and has had subsequent infusion of wild gametes. These lines have been maintained at LPW through ocean ranching of tagged smolts. Comparisons are made between the hatchery lines, progeny of wild chinook collected from the Chickamin and Unuk Rivers, and hybrids between the hatchery and wild groups. Mature ocean-ranched female chinook salmon returning to the facility were periodically graded for ripeness and spawned. Body size and meristic measurements were collected from these mature spawners. Maturation timing, fecundity, and individual egg size of these fourth generation hatchery fish are compared with that of offspring of wild fish from the same donor stock. Stock of origin is confirmed for all spawners and offspring using microsatellite DNA analysis.

Notes: A comparative analysis was performed on sixteen morphometric characters, in three different juvenile sterlet Acipenser ruthenus L. populations. Specimens were collected from a wild population in the Serbian part of the Danube River (n = 46), from aquaculture stocks in the Czech Republic originating from Russia (n = 40), and aquaculture stocks in the Slovak Republic originating from Slovakian part of the Danube River (n = 28). Average values for total length were 29·9 ± 3·9 cm, 29·1 ± 3·7 cm and 27·3 ± 7·7 cm for Serbia, Czech Republic and Slovak Republic, respectively. Populations were compared using t-test and sequential Bonferroni correction for multiple comparisons was applied in order to determine significant differences between them. Results of analysis showed that all three populations differed in prebarbel length, interocular distance and maximum head width. Although all these characters are head-related, head length itself was very uniform among all populations. The natural population from the Serbian part of the Danube River differed from the populations reared in aquaculture in seven morphometric characters. The two populations reared in aquaculture consistently showed lower morphological variability than the wild population, even though they had different genetic backgrounds (Russia and Slovakia). Future genetic studies will show if this tendency is caused by a reduction in genetic variability.

Notes: This paper compiles information new to an earlier list published in 1992. Most changes are (1) additions largely resulting from importation of freshwater species, (2) range extensions of neritic and oceanic epipelagic species, together with (3) the incidental capture of species from within the 200 m bathymetric limit of resident deep pelagic and demersal deep-sea representatives. A list of such species with the potential to stray from residence in the deeper strata of the oceanic region to shelf waters (〈200 m) is presented in appendices.

Notes: European eel (Anguilla anguilla; Teleostei) is a valuable commercial species. However, over the past 25 years, the population of European eel has been declining to such a degree that major concerns have been raised for its long-term conservation. Since little information is available on the life-cycle and genetic structure of European eel, it has been difficult to evaluate the existence of any population substructuring. Molecular genetic methods contribute to a better knowledge of the demography and population structure in marine fish. In addition, management strategies and conservation goals must consider information on genetic substructuring as well as on life history patterns.The aim of the study is to provide more detailed knowledge on the genetic variability, demography and population substructuring of European eel by analysing and comparing natural and farmed individuals. Natural eel samples have been obtained in two geographical sites (Netherlands, France) including temporal samples in a short-scale (within years) and a long-scale (between years). Simultaneously, farmed glass eels have been grown in two separate batches during one year. Batches have been monitored and genetic samples have been obtained during the year.A combination of selection-sensitive (allozymes) and selection-neutral markers (microsatellites) has been used in the study since selection seems to play an important role in the determination of the quality of future eel spawners. Results suggest a positive correlation between growth and genetic variability since individuals attaining a large length and mass present significant higher heterozygosities.

Notes: Blackspot seabream Pagellus bogaraveo is a potential candidate species for southern European aquaculture. A 12-week feeding trial was then conducted to evaluate the effect of dietary protein level on growth performance, body composition and feed use efficiency of blackspot seabream juveniles (22·7 g each). Five isolipidic diets (12·5%) with graded levels of protein (20, 30, 40, 50 and 60%) were hand-distributed, twice a day, to duplicate groups of fish (120 fish per tank), until satiation. Growth (DGC), survival and feed utilization (FCR) were recorded through monthly sampling. Growth performance was significantly affected by dietary protein level (P 〈 0·05), and fish fed at the 50% protein level exhibited the highest final body mass. Feed conversion ratio decreased with increasing levels of dietary protein, fish fed 60% protein being the most efficient. No significant differences were found in whole body composition among treatments (P 〉 0·05). Financed by FCT (Project POCTI/CVT/39239/2001, PhD Grant SFRH-BD-14068–2003)

Notes: In many parts of the world release of hatchery-reared smolts has long been used to mitigate for the deleterious effects of habitat loss and overfishing on salmonid populations. Of increasing concern is whether this may cause harm by spreading non-native stocks and potentially releasing incompetent smolts. The objective of this study was to determine if smolt physiology and behavior of juveniles produced from a recently founded native broodstock differ from their wild (naturally-reared) counterparts. In the fall of 2002 and 2003 juvenile wild steelhead were captured, PIT tagged, and returned (n = 1360 in 2002 and n = 2708 in 2003) to Abernathy Creek. In winter of 2003 and 2004 hatchery-reared fish were PIT tagged and later released (n = 1100 in 2003 and n = 1400 in 2004) into Abernathy Creek. Gill biopsies were collected from wild and hatchery fish throughout the rearing and out-migration season. The timing and speed of outmigration was assessed using two stationary PIT tag antennas (92–97% efficient). Hatchery migrants in 2003 were larger, had significantly lower gill Na+, K+-ATPase activities, and migrated slower than wild fish. Results from the 2004 migratory season will also be presented. This study shows that hatchery rearing can result in smolts which are physiologically and behaviourally different from genetically similar wild fish. Whether these differences are critical enough to affect the rate of adult returns will be determined in future years.

Notes: The depletion of fish stocks in the Mediterranean suggests that restocking may be a useful approach for restoring fisheries. In this paper we consider the potential for using derelict salt pans at Tarquinia (50 miles north of Rome) to rear fish for restocking in adjacent coastal areas. We discuss candidate species for stock enhancement, ways of minimizing stress in the capture of broodstock, genetic monitoring of wild catches, various aspects of operational restocking (release stage of larvae or juveniles, etc) and suggest approaches for evaluating results. Finally, we provide an economic and financial analysis of investment costs and likely benefits for different scenarios, and guidelines for a restocking policy that may be implemented by public authorities.

Notes: Ireland has the world's largest stocks of wild Atlantic salmon. A better understanding of gene expression will benefit conservation of wild stock as well as salmon aquaculture. We describe the PRTLI project designed to advance the fundamental understanding of the genome of Atlantic Salmon Salmo salar. The major objective is to create the first comprehensive database of gene expression and functional information using cDNA libraries and Microarray technology. One key area of interest to salmon biology is osmoregulation, which is critical to the ability of salmon to adapt in seawater. Tissues implicated in this process are the gills, intestine and skin. To initiate studies, SSH (suppression subtractive hybridization) libraries were constructed from intestine RNA extracted from smolts sampled in January and May. A number of potentially interesting clones have been identified, among those a heat shock protein, hsp90 in the reverse library. Others SSH libraries from various tissues (pituitary, hypothalamus, brain, gill, intestine, head kidney and spleen) have also been constructed and will be used to construct a 5000 clone microarray slide. This slide will then be used to elucidate gene expression profiles in various tissues. Further sample collection has been carried out to answer questions regarding biologicaldifferences between one- year and two-year old parr and wild and hatchery smolt.

Notes: The structural organisation of the nucleolar apparatus during oogenesis of the spotted ray Torpedo marmorata was investigated. The observations showed that unlike other cartilaginous fishes, in T. marmorata the nucleolar apparatus was always represented by one or two conspicuous nucleoli, whose organization significantly changed during oocyte development. In the smallest follicles (follicles 〈300 μm in diameter) the nucleolus was made up of granular and fibrillar components, and actively incorporated 3H uridine; later it becomes more and more electron-dense so in follicles of 400 μm in diameter its components and 3H uridine incorporation were no longer evident. These results indicate that in T. marmorata the nucleolar apparatus significantly changes and undergoes a possible impairment in rRNA synthesis. After nucleolus inactivation, the synthesis of rRNA may be substained by granulosa.

Notes: Leucocyte lysates from rainbow trout Oncorhynchus mykiss showed an iron-binding activity that was retained even if the samples were exposed to an acid pH (4·5). Iron-binding activity of leucocyte supernatants was enhanced by the presence of 1 μg ml−1 phorbol-12-myristate-13-acetate in the cell medium.

Notes: The role of the eel Anguilla anguilla as a piscivorous species was investigated in a biomanipulation experiment in the mesotrophic Saidenbach Reservoir. The distribution and abundance of the eels were investigated by point abundance sampling, snorkelling and scuba diving. Also, the total yearly consumption of the eel population was compared with the standing stock of prey fishes and the production of roach Rutilus rutilus eggs. A restricted availability of shelter habitats at low water levels had no influence on the distribution of the eels during the nocturnal activity period. Fishes were consumed in low numbers but in high proportions of biomass by large eels. The maximum estimate of the annual consumption of the prey fish standing stock by the eels was 19%. Fish eggs were consumed during a small time period by a large proportion of the eels but the total consumption was 〈10% of the total annual production of roach eggs. By consuming small individuals of planktivorous fishes, the eels contribute to the biomanipulation programme in the Saidenbach Reservoir.

Notes: The ontogenetic patterns of habitat use by a community of fishes in the main channel of the Broken River, an Australian lowland river, was investigated. Stratified sampling was conducted fortnightly across six habitat types throughout the spring-summer period within the main channel. As predicted by the ‘low flow recruitment hypothesis’, backwaters and still littoral habitats were important nursery habitats for most species. These habitats were found to be used by some species throughout all stages of their life cycle, while other species showed clear ontogenetic shifts in habitat preference. Only one species, Murray cod Maccullochella peelii peelii, was never found in backwaters. This study confirms the significance of main channel habitats in the rearing of larvae of some riverine fish species, and emphasizes the importance of considering the habitat requirements of all stages of a fish's life cycle in the management and restoration of rivers and streams.

Notes: In this study, the combined influence of vegetation density and water turbidity on habitat utilization of a prey fish, 0+ year perch Perca fluviatilis, under predation risk (pike, Esox lucius) was investigated. The vegetated habitat was overall preferred over the open habitat in the presence of a predator. The level of turbidity, and to a lesser extent vegetation density, however, influenced the response of 0+ year perch. The use of the vegetated habitat was lower in very turbid than in clear and turbid conditions, suggesting reduced antipredator behaviour in very turbid water. The effect of vegetation density on antipredator behaviour was only present in clear water, where the use of a structural refuge decreased with increasing vegetation density. No such effect was observed in turbid and very turbid water. The results showed that the structuring role of vegetation or habitat complexity may diminish with increased turbidity. The observed masking effect of turbidity suggests that predator-prey interactions in vegetated habitats are more complex than what has generally been thought.

Notes: Perch Perca fluviatilis recruitment (based on the catch per unit effort, CPUE, of 2 or 3 year male perch) varied greatly from 1941 to 1995 in Windermere, U.K., with year class strengths strongly synchronous between the two basins of this temperate, mesotrophic lake. Statistically significant modified Ricker (Saila-Lorda) stock-recruitment curves could be fitted to data from three of four sampling sites, while the presence of widespread disease and late summer water temperature were also important explanatory variables. Multiple-regression analyses revealed no influences of pike Esox lucius recruitment, zooplankton abundance, or the climatic influences (i.e. North Atlantic Oscillation and displacement of the summer position of the Gulf Stream) on perch recruitment over and above associated influences from temperature. Fitted models realistically explained up to c. 60% of the observed variation in perch recruitment.

Notes: Olfactory sensitivity of juvenile (0 year) Atlantic cod Gadus morhua to 20 L-amino acids was studied by recording electroencephalograms (EEG) from the olfactory bulb. Leucine, methionine, asparagine, glutamine, alanine and threonine were highly stimulatory; proline, phenylalanine, aspartic acid and tryptophan were the least stimulatory. Threshold concentrations determined for four amino acids were 10−8 M for alanine, 10−7 M for arginine and leucine and 10−6 M for glutamic acid.

Notes: The variability in size structure and relative abundance (CPUE; number of fish ≥200 mm total length, LT, collected per hour of electrofishing or trammel netting) of three native Colorado River fishes, the endangered humpback chub Gila cypha, flannelmouth sucker Catostomus latipinnus and bluehead sucker Catostomus discobolus, collected from electrofishing and trammel nets was assessed to determine which gear was most appropriate to detect trends in relative abundance of adult fishes. Coefficient of variation (CV) of CPUE ranged from 210 to 566 for electrofishing and 128 to 575 for trammel netting, depending on season, diel period and species. Mean CV was lowest for trammel nets for humpback chub (P = 0·004) and tended to be lower for flannelmouth sucker (P = 0·12), regardless of season or diel period. Only one bluehead sucker 〉200 mm was collected with electrofishing. Electrofishing and trammel netting CPUE were not related for humpback chub (r = −0·32, P = 0·43) or flannelmouth sucker (r = −0·27, P = 0·46) in samples from the same date, location and hour set. Electrofishing collected a higher proportion of smaller (〈200 mm LT) humpback chub (P 〈 0·001), flannelmouth suckers (P 〈 0·001) and bluehead suckers (P 〈 0·001) than trammel netting, suggesting that conclusions derived from one gear may not be the same as from the other gear. This is probably because these gears fished different habitats, which are occupied by different fish life stages. To detect a 25% change in CPUE at a power of 0·9, at least 473 trammel net sets or 1918 electrofishing samples would be needed in this 8 km reach. This unattainable amount of samples for both trammel netting and electrofishing indicates that detecting annual changes in CPUE may not be practical and analysis of long-term data or stock assessment models using mark-recapture methods may be needed to assess trends in abundance of Colorado River native fishes, and probably other rare fishes as well.

Notes: The effectiveness of baited fishing gear ultimately depends upon behaviour of the target species – activity rhythms, feeding motivation, and sensory and locomotory abilities. While any environmental parameter that mediates feeding or locomotion can have an important influence on the active space presented by the bait and fish catchability, few biologists have considered how such variation in behaviour might affect catch per unit effort (CPUE) and the resultant stock abundance estimates or population parameters. This review reveals that environment-related variation in feeding behaviour can act through four different mechanisms: metabolic processes, sensory limitations, social interactions and direct impacts. Water temperature, light level, current velocity and ambient prey density are likely to have largest effects on fish catchability, potentially affecting variation in CPUE by a factor of ten. Feeding behaviour is also density-dependent, with both positive and negative effects. Over time and geographic space a target species can occupy wide ranges of environmental conditions, and in certain cases, spatial and temporal variation in feeding biology could have a larger impact on CPUE than patterns of abundance. Temperature, light and current can be measured with relative facility and corrections to stock assessment models are feasible. Making corrections for biological variables such as prey density and bait competitors will be more difficult because the measurements are often not practical and relationships to feeding catchability are more complex and poorly understood. There is a critical need for greater understanding of how environmental variables affect feeding-related performance of baited fishing gear. A combination of field observations and laboratory experiments will be necessary to parameterize stock assessment models that are improved to accommodate variation in fish behaviour. Otherwise, survey data could reveal more about variation in behaviour than abundance trends.

Notes: The body colouration extending into ultraviolet wavelengths in three species of Lake Malaŵi rock-dwelling cichlids, Metriaclima zebra, Metriaclima benetos and Metriaclima barlowi was quantified. All three species were ultraviolet reflective with interspecific differences in reflectivity. In addition, individuals were able to behaviourally mediate their reflectivity.

Notes: After conditioning Nile tilapia Oreochromis niloticus for 2 weeks, the photoperiod regime of 12 tanks of fish was changed to a 6L : 6D photoperiod while 12 further tanks were retained on the conditioning photoperiod regime (12L : 12D). Blood samples were collected 3 days (first sampling) and 3 months (second sampling) after changing the photoperiod regime. Blood was collected at 6 h intervals from both photoperiod regimes (1000, 1600, 2200 and 0400 hours). At the first sampling time, fish in the 6L : 6D had significantly higher cortisol both in the light and dark phases than levels in fish in the 12L : 12D photoperiod. At the second sampling time, the levels were significantly higher only in the light phase. The levels of cortisol, glucose and Cl− in fish exposed to the 6L : 6D photoperiod, however, were far lower than those of acute stress-induced levels observed in fish exposed to a stress experiment. Furthermore, there were no significant differences in overall values of all the variables between the photoperiod regimes at the second sampling time. This indicated that the fish exposed to the 6L : 6D photoperiod were not chronically stressed. Significantly higher blood lymphocyte counts were observed in fish exposed to the 6L : 6D compared to those of the 12L : 12D photoperiod during the light phase at the second sampling time. Other variables (glucose, Cl−, haematocrit and neutrophil) did not show a significant difference between the treatments at either sampling time. These results demonstrated that the artificial photoperiod regime did not cause a significant acute or chronic stress response in Nile tilapia.

Notes: The ‘smoothed’(4253e HT smoother) 6 year time series with a monthly periodicity of catches (where the increases of the catches reflect the spawning migration) of Mugil cephalus and Mugil curema, were correlated (Pearson correlation index) against the ‘smoothed’ data on rainfall, water temperature, daylight and tide monthly averages. Water temperature and M. curema spawning migrations had a negative correlation (r = −0·77), while tide monthly averages and M. cephalus spawning migrations were positively correlated (r = 0·84). The two environmental variables that showed highly significant correlations were water temperature and daylight (r = 0·85, P 〈 0·05). Meteorological tides were used as a reflection of the effect of the north winds from the Gulf of Mexico which produce an average tide rise from September to November. The relationship of these variables with spawning migrations is discussed, and it is suggested, in particular, that meteorological tides, as a reflection of the north winds, are the trigger (zeitgebers) for M. cephalus spawning in the ocean.

Notes: The catfishes Brachyplatystoma flavicans(n = 49) and Pseudoplatystoma fasciatum(n = 69) showed comparable low allozyme diversities (He = 0·012 and 0·009–0·028, respectively), but contrasting PCR-RFLP restriction site mitochondrial DNA diversities (three haplotypes: π = 0·034–0·092 and five haplotypes: π = 0·001–0·023, respectively) in the Rio Ichilo and Beni (Bolivia). Genetic homogeneity between samples was high for B. flavicans and lower for P. fasciatum. Based on mitochondrial diversity, both species probably experienced a historic population reduction but at different time scales.

Notes: Three cryoprotectants [dimethyl sulphoxide (DMSO), propylene glycol (PG) and glycerol], two diluents (sucrose- and saline-based), two sperm collection times, two freezing rates and three times between thaw and activation (0, 30 and 60 min) were tested in order to develop a protocol for the cryopreservation of sperm of haddock Melanogrammus aeglefinus and Atlantic cod Gadus morhua. The faster freezing rate resulted in extremely low post-thaw motility in comparison to the slower freezing rate, which was successful for sperm from both gadids. In both cases, the use of PG resulted in significantly higher post-thaw sperm motility-recovery indices than with DMSO or glycerol, which did not differ significantly from one another. Diluent had no effect on post-thaw sperm motility for Atlantic cod or haddock. Sperm collected at the end of the spawning season tended to have reduced post-thaw motility compared to that collected 2 weeks after the start of spawning. A 30 min delay between thaw and activation of haddock and Atlantic cod sperm resulted in a significant decrease in sperm motility. When PG was used as cryoprotectant, sperm motility continued to decrease between 30 and 60 min post-thaw. With DMSO or glycerol as cryoprotectant, motilities were already very low after 30 min post-thaw and did not decrease any further after 60 min. Cryoprotectant, diluent and time between thaw and activation had no effect on mean or maximum sperm swimming speeds for either Atlantic cod or haddock sperm. Fertilization success for haddock eggs, like sperm motility, was higher with PG-frozen sperm than DMSO- or glycerol-frozen sperm. These results constitute the first reported successful cryopreservation of haddock sperm and improve on previous methods used to cryopreserve sperm from Atlantic cod.

Notes: The present study examined the effects of competition on male courtship in the Pacific blue-eye Pseudomugil signifer, a species of fish where females have previously been shown to use courtship, but not male fighting prowess, as an important mate choice cue. Courtship bouts directed to a stimulus female were shortest when two males were allowed to freely interact (contact treatment) and longest when there was only one male (non-interaction). Courtship length in trials where one of two males was confined to a clear cylinder (visual) was intermediate between the other two treatments. Courtship in visual and contact treatments was constantly disrupted. The percentage of interrupted courtships was higher for the contact compared to visual treatment where aggressive interactions were also longer in duration and took place more frequently. Within contact trials, dominant males courted longer than subordinates despite both males experiencing comparable rates of courtship disruption. These results suggest that male-male competition can have important implications for adaptive female choice particularly in circumstances where the benefits being sought by females are unrelated to male fighting ability.

Notes: The effect of school size on capture success in three different piscivores, perch Perca fluviatilis, pikeperch Stizostedion lucioperca and pike Esox lucius, was investigated. Roach Rutilus rutilus were used as prey in a pool experiment where individual predators were presented prey at densities of one, two, four, eight and 16 prey, respectively. Treatments were replicated seven times for each predator species. Perch was at first virtually unable to capture a prey from a school and suffered a significant confusion effect with increasing prey density. The effect, however, was limited in the long run, as the perch was a very effective predator in its hunting strategy where it singled out and repeatedly attacked single prey irrespective of prey density or school size. Pikeperch and pike were able to attack and capture prey at any prey density equally successfully and thus did not suffer from a confusion effect. Neither did these predators receive any apparent advantages from increasing prey density.

Notes: The sagitta of Kurtus gulliveri was ovate, moderately thick with the following attributes: lateral surface convex, mesial surface flat; dorsal margin sinuate, posterior margin rounded ventrally, ventral margin rounded and irregular; sulcus divided into ostium and cauda by constriction of dorsal and ventral margins, heterosulcoid, colliculum heteromorph; dorsal depression large and distinct, ventral groove close to margin in larger otoliths; rostrum broad and antirostrum small, separated by wide, shallow excisural notch. Otolith size was moderate, average 4·6% standard length (LS), typical for a perciform. Annuli on 78 whole sagittae were read, and 15% of these were transversely sectioned for verification of the annuli. Males ranged from 94 to 235 mm LS and females from 95 to 284 mm LS. There was little difference in size distribution of the sample between the sexes, perhaps due to a 6 month spawning season over which young were continually added to the population. Some sexual dimorphism was noted, however, as age 2 year females were significantly larger than males of the same age. The largest fish aged was a 284 mm LS, 3 year-old female, and the oldest age reached was 4 years by two males. It appears likely that most spawning females are ≥2 years old, but some larger 1 year old fish may attain sexual maturity.

Notes: The population structure of ‘lake-type’ and ‘river-type’ sockeye salmon Oncorhynchus nerka, primarily in transboundary rivers in northern British Columbia, was examined with a survey of microsatellite variation. Variation at 14 microsatellite loci was surveyed from c. 3000 lake-type and 3200 river-type sockeye salmon from 47 populations in six river drainages in British Columbia. The mean FST for the 14 microsatellite loci and 47 populations was 0·068, and 0·034 over all river-type populations. River-type sockeye salmon were more genetically diverse than lake-type sockeye salmon, with expected heterozygosity of river-type sockeye salmon 0·72 and with an average 12·7 alleles observed per locus, whereas expected heterozygosity of lake-type sockeye salmon was 0·65 with and average 10·5 alleles observed per locus. River drainage of origin was a significant unit of population structure. There was clear evidence of genetic differentiation among river-type populations of sockeye salmon from different drainages over a broad geographic range in British Columbia.

Notes: Upstream migration rates were assessed for 1801 radio-tagged adult spring–summer Chinook salmon Oncorhynchus tshawytscha through 12 unimpounded river reaches in the Columbia River basin from 1997 to 2002. Reaches were 36 to 241 km long (mean = 130 km) and included sections of the large Columbia and Snake Rivers and smaller free-flowing tributaries. Median Chinook salmon migration rates ranged from 〈10 km day−1 in the Deschutes and Clearwater Rivers to 〉35 km day−1 in the Columbia and Snake Rivers. Using multivariate analyses, migration date explained the most variance in Chinook salmon migration rates while river discharge, migration year and migration reach were secondary. Both within and between years, Chinook salmon migrated more rapidly as migration date increased and more slowly when discharge was high. Arrival at high elevation spawning grounds at appropriate times and increased metabolic activity and reproductive maturation may explain the greater power of migration date, relative to river discharge, in predicting migration rates of Columbia basin spring–summer Chinook salmon.

Notes: Variation in respiratory traits was quantified between two populations of the sailfin molly Poecilia latipinna(one from a periodically hypoxic salt marsh, Cedar Key, and one from a chronically normoxic river site, Santa Fe River). Two suites of characters were selected: traits that may show both short-term acclimation response and interdemic variation in acclimation response (metabolic rate, critical oxygen tension and respiratory behaviour), and those that are not likely to respond to short-term acclimation but may vary among populations (gill morphometric characters). Sailfin mollies from the salt marsh, acclimated to hypoxia (1 mg l−1, c. 20 mmHg) for 6 weeks, spent less time conducting aquatic surface respiration and had lower gill ventilation rates than hypoxia-acclimated conspecifics from the well-oxygenated river site. Poecilia latipinna acclimated to hypoxia exhibited a lower critical oxygen tension (Pc) than fish acclimated to normoxia; however, there was also a significant population effect. Poecilia latipinna from Cedar Key exhibited a lower Pc than fish from the Santa Fe River, regardless of acclimation. Cedar Key fish had a 14% higher mean gill surface area relative to fish from the Santa Fe River, a character that could account, at least in part, for their greater tolerance to hypoxia.

Notes: The β2-adrenergic agonists (β2-AAs) clenbuterol (CLEN) and ractopamine (RACT) were fed to rainbow trout Oncorhynchus mykiss for 30–37 days and red and white muscle β2-adrenoceptor (β2-AR) binding characteristics and mRNA expression were assessed in parallel with fractional protein synthetic rates. Feeding CLEN or RACT had no significant effect on any body or physiological variables measured. There were no significant differences in the number of binding sites (Bmax) while a significant increase in the Kd was observed for the β-ARs of red and white muscle membranes isolated from β2-AA-fed rainbow trout. No change in β2-AR mRNA levels was observed with β2-AA feeding, implying that these β2-AAs do not act at the transcriptional level at least for the β2-AR. The β2-AA treatments, however, did significantly increase red and white muscle fractional protein synthesis rates in whole protein, myofibrillar protein and sarcoplasmic soluble protein fractions. Although not conclusive, this study supports a direct link between rainbow trout muscle β2-ARs and muscle protein synthesis.

Notes: Depending on population, wild Fraser River sockeye salmon Oncorhynchus nerka travel distances of 〈100 km to 〉1100 km and ascend elevations ranging from near sea-level to 1200 m to reach spawning areas. Populations embarking on distant, high elevation migrations (i.e. Early Stuart, Chilko and Horsefly populations) began their upriver spawning migrations with higher densities of somatic energy (c. 9·2 to 9·8 MJ kg−1) and fewer eggs (c. 3200 to 3800) than populations making shorter, low elevation migrations (i.e. Weaver and Adams; c. 7·1 to 8·3 MJ kg−1 gross somatic energy and c. 4300 to 4700 eggs). Populations making difficult upriver migrations also had morphologies that were smaller and more fusiform than populations making less difficult migrations, traits that may facilitate somatic energy conservation by reducing transport costs. Indeed, fish travelling long distances expended less somatic energy per unit of migratory difficulty than those travelling shorter distances (2·8 to 3·8 kJ v. 10–1400 kJ). Consistent with evolutionary theory, difficult migrations appear to select for energy efficiency but ultimately fish making more difficult migrations produce fewer eggs, even when differences in body length have been accounted for. Despite large among-population differences in somatic energy at the start of upriver migration, all populations completed migration and spawning, and subsequently died, with c. 4 MJ kg−1 of energy remaining, a level which may reflect a threshold to sustain life.

Notes: The distributional diversity and assemblages of fish larvae in the Gulf of California indicated two main seasonal stages and two transitional periods: in winter, the tropical water mass is confined to the south-east portion of the mouth of the Gulf and larval fish assemblages are dominated by subtropical and temperate-subarctic species; in summer; tropical water invades the Gulf and assemblages are dominated by tropical species. Both seasonal stages are separated by transitional periods coinciding with strong latitudinal temperature gradients. During the autumn and spring transitional periods, the Gulf of California splits into three regions: a northern region where temperate and subarctic species spawn from autumn to spring, a southern region dominated by tropical and subtropical species year round and a central region where tropical and temperate assemblages merge. Seasonal changes in the location of the regions, as well as the borders between them, show expansion and contraction of the northern and southern faunas related to the general oceanic circulation patterns during the year.

Notes: Three digestive enzymes in four species of closely related prickleback fishes (family Stichaeidae: Cebidichthys violaceus, Xiphister mucosus, Xiphister atropurpureus and Anoplarchus purpurescens) were analysed to assess whether diet or phylogeny played a larger role in influencing digestive enzyme activity. Cebidichthys violaceus and X. mucosus are primarily herbivorous, whereas X. atropurpureus and A. purpurescens are mainly carnivorous. The two Xiphister species are sister taxa, and A. purpurescens is in a clade adjacent to that of the three other species. Pepsin and trypsin specific activities did not differ significantly among the four species, but α-amylase activity was significantly higher in the two Xiphister species, followed by C. violaceus, and then A. purpurescens. The wide disparity between the two carnivores, the striking similarity between the two sister taxa, and the significant difference between the two herbivores indicate that activity of α-amylase follows a pattern influenced more by phylogeny than by diet in these fishes.

Notes: The stomach contents of adult brown trout Salmo trutta from Lake Sorell, Tasmania, were analysed during 6 years of increasing turbidity to follow changes in the diet associated with dramatic changes in water clarity. Brown trout were sampled from 1996, when turbidity was 26 NTU, to 2001 when turbidity was 141 NTU. The mean relative volume of stomach contents decreased progressively to 2001, by which time it was only one sixth of that in 1996, and the mean diversity of prey in stomachs decreased from an average of more than six species per stomach in 1996 to one species in 2001. The species composition of stomach contents shifted from domination by the phreatoicid isopod Colubotelson sp., to the galaxiid fish Galaxias auratus and the amphipod Austrochiltonia australis, and then the cladoceran Daphnia carinata. To give an indication of diet changes over a typical yearly cycle in the current turbid state of the lake, a sample was taken from each season from December 2000 to September 2001. Two basic diets were found during the year; brown trout specialized on D. carinata in summer and autumn, and G. auratus in winter and spring. Mean diversity of prey was less than two species per stomach in all samples from 2000 to 2001, except for the sample from spring 2001 when it was 2·2 species per stomach, and the mean relative volume of stomach contents was more than three times greater in winter than any other season. The ways in which high turbidity may have influenced the changes in the brown trout diet observed since 1996 and the patterns evident during the seasons of 2000–2001 are discussed.

Notes: Two populations from Wonzye and Nkumbula Island, Lake Tanganyika, containing both rock and shell-bed dwelling individuals of the genus Telmatochromis were analysed by means of comparative morphological and DNA haplotype data from the mitochondrial control region. The data on individuals from rock v. shell-bed habitats allowed a clear discrimination to be made between habitats, while there was no distinction among individuals of the same habitat from Wonzye and Nkumbula. The shell-bed dwellers had small body size, including smaller size at sexual maturity and fewer eggs than rock dwellers. The existence of two distinct species that diversified according to habitat choice is suggested.

Notes: Three separate effects on refuge use by signal crayfish Pacifastacus leniusculus and Atlantic salmon Salmo salar were examined: (1) the effect on Atlantic salmon of an addition of signal crayfish (doubling the total number of animals), (2) the effect on signal crayfish of an addition of Atlantic salmon and (3) intraspecific compared with interspecific competition, compared by holding total density of animals constant and varying the proportion of signal crayfish and Atlantic salmon in trials. Observations were made during winter, when both species are nocturnal. The proportion of Atlantic salmon sheltering was significantly lower in the presence than in the absence of signal crayfish when the interspecific treatment (Atlantic salmon plus signal crayfish) effected a doubling in density compared to the intraspecific treatment (Atlantic salmon alone). The proportion of signal crayfish sheltering was independent of the presence of Atlantic salmon. When total density was constant, the proportion of Atlantic salmon sheltering was significantly higher in intraspecific (52·8%) than interspecific trials (27·3%). Atlantic salmon out of shelter during the day in winter are believed to be very vulnerable to predators and the capacity for fish to share shelters with one another is known to be very low. Therefore, competition from crayfish for winter shelters may lead to detrimental effects on Atlantic salmon populations.

Notes: Laboratory observations of live animals were used to describe the developmental sequence of the flounder Pleuronectes flesus. Developmental state was related to age and total length (LT) from hatching, through metamorphosis, to the juvenile form. By following animals at 7, 11 and 15° C it was found that, whilst the LT at metamorphosis was the same for all the temperature regimes and was not temperature-dependant, the time taken to reach this stage was related to rearing temperature. It was also observed that animals could be induced to metamorphose by transfer to reduced salinity but only if they were close to the critical length for metamorphosis.

Notes: The effect of six different feeding times was tested on feed intake, growth performance, proximate body composition and nutrient retention in the rainbow trout Oncorhynchus mykiss. Using a non-linear regression model, a significant rhythmic pattern over a 24 h period was observed for feed gain ratio and nutrient retention responses to feeding time. Specific growth rate and protein growth rate responses were also rhythmic but the trends were not significant. There was no clear effect of feeding time on feed intake and proximate body composition. The study suggested that feed intake, at least under the experimental conditions encountered, was synchronized to feeding time while some physiological rhythms involved in nutrient metabolism were probably synchronized to photoperiod.

Notes: The effect of time of stocking on the extent and source of mortality in 0+ year pike Esox lucius was investigated in a lake (20 ha) and a drainable pond (0·5 ha) using pike with alizarin marked otoliths. The results indicated that pike stocked late relative to the recruitment of native 0+ year pike fell victim to cannibalism from these larger individuals. This resulted in very low survival through the first growing season (〈2%). Pike stocked early in the season exhibited significantly higher survival (〉12%). Analyses of the size distribution of the alizarin marks from these fish revealed that the largest 0+ year pike exhibited by a factor of 3·3, higher survival than the average 0+ year pike in the lake. In order for large 0+ year pike to exhibit such high relative fitness a minimum of 69·7% of the original population must suffer size dependent mortality. In the pond the survival of the largest pike was by a factor of 4·2 higher than the average pike, and the corresponding size dependent mortality was 76·4%. The substantial size-dependent mortality was most probably due to intra-cohort cannibalism or habitat segregation between large and small 0+ year pike that exposes the small pike to predatory fishes in the open lake. Cannibalism exerts a major influence on the survival of 0+ year pike post-stocking although the magnitude and origin differ in relation to stocking time.

Notes: Scomberomorus niphonius juveniles were fed with alternative prey differing in body shape: elongate and laterally compressed (clupeid or gobiid larvae) and deep-framed bodies (paralichthyid larvae) in aquaria. The ratio of prey larvae with elongate and laterally compressed body: prey larvae with deep-framed body in the aquaria was 1 : 1. The juveniles fed almost exclusively on the larvae with an elongate and laterally compressed body.

Notes: At Heron Island reef, Great Barrier Reef Australia, biomass densities and mean wet mass of Ward's damselfish Pomacentrus wardi and the jewelled blenny Salarias fasciatus were not significantly different at 2·37 v. 2·95 g m−2 and 8·7 v. 7·9 g, respectively. Whereas S. fasciatus significantly exceeded P. wardi in (1) total number of bites per day (3427 v. 1155), (2) the mass of epilithic algal community consumed per bite (2·19 v. 0·14 mg) and (3) total organic carbon consumed per day (487·31 v. 35·46 mg C m−2 day−1). Territorial behaviour differed also between the two species. Pomacentrus wardi chased from their territories a smaller proportion of blennies than roving grazers (i.e. scarids, acanthurids, siganids and pomacentrids) relative to S. fasciatus. Salarias fasciatus chased c. 90% of other blennies from their territories, while chasing only c. 20% of all damsels that entered. Both P. wardi and S. fasciatus rarely chased non-grazers. The chasing behaviour of S. fasciatus was size dependent, with resident fish chasing only individuals of its own family (i.e. Blenniidae) that were the same or smaller size. Pomacentrus wardi may have tolerated S. fasciatus grazing within its territory, as it contributes to territory defence from other blennies. The possibility that the interaction between the two species is facilitative, rather than competitive, is discussed. It was concluded that salariine blennies play an important, and previously underestimated role in coral reef trophodynamics.

Notes: We present the first synthesis of the life history and ecology of seahorses, compare relationships for seahorses with other marine teleosts and identify research needs. Seahorses occurred primarily amidst temperate seagrasses and tropical coral reefs. Population densities were generally low, ranging from 0 to 0·51 individuals m−2, but reached 10 m−2 in some patches. Inferred life spans ranged from 1 to 5 years. Seahorses consumed live prey and possibly changed diet as they grew. Growth rates are poorly investigated to date. Reproduction and mating systems are the best-studied aspects of seahorse ecology. The relationship between size at first maturity and maximum size in seahorses conformed to that for other marine teleosts. All seahorse species were monogamous within a cycle, but some were polygamous across cycles. Direct transfer of clutches to the brood pouch of the male fish made it difficult to measure clutch size in live seahorses. After brooding, males released from c. 5 to 2000 young, depending on species and adult size. Newborn young measured from 2 to 20 mm in length, which was a narrower size range than the 17-fold difference that occurred in adult size. Newborn body size had no relationship to adult size. Both eggs and young were larger than expected among marine teleosts, even when considering only those with parental care, but brood size at release was lower than expected, perhaps because the young were more developed. The size of adults, eggs and young increased with increasing latitude, although brood size did not. Considerable research is needed to advance seahorse conservation and management, including (a) fisheries-dependent and fisheries-independent abundance estimates, (b) age- or stage-based natural and fishing mortalities, (c) growth rates and age at first maturity, and (d) intrinsic rates of increase and age- or size-specific reproductive output. Current data confirm that seahorses are likely to be vulnerable to high levels of exploitation.

Notes: Population densities of landlocked lake-migratory brown trout Salmo trutta were estimated in two distinct lotic sections, separated by a lentic segment, in the Greåna River, Sweden, and individual growth and habitat use were monitored for 835 tagged brown trout from September 1998 to June 2000. Residency dominated in the upstream section where density of 0+ and 1+ year brown trout was low and growth rate high. In contrast, 〉90% of the brown trout that migrated to the lake originated from the downstream section, where density was high and growth rate low. For ≥2+ year individuals, growth rate was similar between the two stream sections, but densities were higher in the upstream than in the downstream section. Lake-migrants had higher growth rates than non-migrants (residents) during the autumn of both years. From September to May, migrants increased their body mass by 〉35%, whereas non-migrants increased by 〈5%. Approximately 70% of the brown trout moved 〈10 m and 〈2% moved between the two stream sections, indicating that the lentic habitat might function as a barrier for juveniles. Differences in migratory behaviour, density and growth between the upstream and the downstream section might indicate that environmental factors influence the decision to migrate. It cannot be excluded, however, that the observed differences are genetically programmed, selected by migration costs that favour migratory behaviour downstream and residency upstream.

Notes: Utah chub Gila atraria, a temperate freshwater minnow, formed valid otolith annuli (annual growth rings), even when raised in a constant-temperature desert spring environment. This suggests that factors other than seasonal variation in water temperature control annual otolith marking.

Notes: The ionic levels of the gallbladder bile of 23 species of teleosts from the Rio Negro, Amazon, were analysed. Ionic levels of the gallbladder bile were variable according to the species and could not be related to the feeding habit or fullness of the gut.