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  • 1
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Male red frog crabs, Ranina ranina, were collected year round in 1990 and 1991 off Hachijojima for histological study of the reproductive system and cycle. The testis containing the lobules and seminiferous ducts is surrounded by connective tissue. The seminiferous duct connects to the anterior end of the vas deferens, which can be histologically divided into three portions similar to one another in appearance. It was surrounded by fibrous connective tissue, muscle fibrils and columnar epithelium. Muscle fibrils were absent in the anterior portion. Multiple sperm masses were not formed in the vas deferens and ejaculatory duct, but the sperm mass was covered with a capsule composed of two layers. The outer layer of the capsule was periodic acid Schiff (PAS)-positive, but the inner layer was negative. Both layers were Alcian Blue negative, except the vacuoles in the outer layer that were stained blue. The small round androgenic gland was attached to the posterior end of the vas deferens of the coxa of the eighth thoracic appendage. The ejaculatory duct was distinguishable from the vas deferens by the absence of columnar epithelium and the presence of thick longitudinal muscle fibers. Spermatogenesis was histochemically examined. The acrosomal vesicle appeared to be derived from PAS-positive vesicles in the cytoplasm of the spermatid at the early stage of spermiogenesis. The arms were positive to the Feulgen reaction and the subacrosomal region was negative to PAS. Seasonal changes in reproductive cycle were inconspicuous histologically and microscopically. Sperm were always present in the testis and vas deferens throughout the year and occupied 5.1 to 19.6% of testis observed in cross sections. The minimum size of maturity is less than 39 mm carapace length, but the minimum size capable of successful mating was estimated to be ca. 55 mm.
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  • 2
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Speciments of the red frog crab, Ranina ranina, examined in this study were collected off Hachijojima, Japan from 1987–1988 and 1990–1991. Ovigerous females occurred from May to September, and their carapace length ranged from 61.8 to 102.1 mm. Minimum size at the maturity was estimated to be 50 to 60 mm carapace length. The lobule-type ovary had a longitudinal ovarian cavity at the center. Germinal zones were located along the sides of the cavity. Oogenesis was divided into five main and ten detailed stages: proliferation (oogonium); previtellogenesis (bouquet, early chromatin nucleolus, late chromatin nucleolus); primary vitellogenesis (oil globule and yolk granule); secondary vitellogenesis (primary yolk platelet, secondary yolk platelet and prematuration); and maturation (maturation) stages. Vitellogenesis started at the oil globule stage when weakly positive periodic acid-Schiff granules appear in the cytoplasm. Based on the gonadosomatic index and histological changes in ovary, the reproductive cycle was divided into five stages: multiplication, from December to January; developing, from February to March; ripe in April and early May; spawning, from late May to August; and recovery, from August to November. Each crab spawned more than once during the spawning season.
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  • 3
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Mutation Research/Environmental Mutagenesis and Related Subjects 31 (1975), S. 265 
    ISSN: 0165-1161
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 32 (1988), S. 0 
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The feeding activity of an individual fish larva is described by an equation which includes parameters for the area successfully searched, probability of food capture multiplied by the cross-sectional perceptive visual field, larval swimming speed and the time required to consume a unit of food energy. The proportion of ingested food energy used for metabolism increases exponentially with increasing swimming speed. The model predicts that food consumption rate increases asymptotically whereas metabolic rate increases exponentially. This results in a predicted growth rate curve that reaches a maximum at a certain swimming speed and decreases at both higher and lower speeds.The model can be used to predict the influence of type of prey, prey density, water temperature etc. on larval growth. An expression describing how many hours per day fish larvae must forage in order to grow at a certain daily body weight gain allows the limits of environmental conditions for positive, zero and negative growth rate to be set.Results of simulations demonstrated that the optimum swimming speed for maximum growth of coregonid larvae increased with an increase in food density, decrease in water temperature or decrease of prey vulnerability. At optimum ‘theoretical’ swimming speed an increase in water temperature from 5 to 17° C required the food density to be increased from 20 to 80 copepods l−1 in order to maintain a daily growth increment of 2%. The minimum Artemia density required for maintenance metabolism increased from 10 to 30 items 11 over the same temperature increase from 5 to 17° C, and food densities required for 8% growth rates were 26 and 56 Artemia nauplii l−1 at 5 and 17° C, respectively.Contrary to previous findings, results of the present study suggest that metabolic rates of actively feeding fish larvae may be from 5 to 50 times the standard metabolic rate: earlier studies suggested that a factor of 2–3 may be generally applicable.
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  • 5
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: This study reports the occurrence of spontaneous hybridization between Odontesthes bonariensis (Valenciennes, 1835) and Patagonina hatcheri (Eigenmann, 1909), two South American freshwater atherinids, while adults of both species were being held in a communal laboratory tank, and describes suitable genetic markers for distinction of both species and their hybrids. Combined allozyme and mitochondrial DNA restriction length polymorphism analyses of offspring from three spawnings in the communal tanks confirmed the presence of hybrids along with purebreds in each spawning. Hybrids of an O. bonariensis mother X a P. hatcheri father were produced along purebred O. bonariensis in one occasion, whereas hybrids of P. hatcheri mothers X O. bonariensis fathers were produced along purebred P. hatcheri in two occasions. Three enzyme systems (coded by loci LDH-B*, PGM*, and CK*) out of 15 (20 loci) screened allowed distinction of species and their hybrids, but the usefulness of LDH-B* for field work may be limited by intraspecific polymorphism. Eight restriction enzymes (Apa I, Bgl II, Eco RI, Eco RV, Eco T22I, Hinc II, Hind III, and Pvu II) among 11 produced diagnostic restriction fragments applicable for species (motherhood) distinction. The relevance of these findings for the management of natural genetic resources and the aquaculture of these two species is discussed.
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  • 6
    ISSN: 1365-2095
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Mass seed production depends a great deal on the development of adequate artificial diets, which in turn depends on the development of methods to speedily and reliably assess the nutritional value of experimental diets. This study examined the sensitivity of light histological and ultrastructural criteria to detect differences in the nutritional value of diets for the Japanese spiny lobster, Panulirus japonicus (V. Siebold), phyllosoma larvae. The acceptability of diets, the apparent absorption of lipids and carbohydrates by the midgut gland cells, and the characteristics of various cell types were determined in 43-, 106- and 143-day-old intermoult phyllosoma fed diets of Mytilus edulis (L.) ovary alone (MO) or in combination with Anemia (MO+AR), which so far have given the best results in terms of growth and percentage of metamorphosis into puerulus, and two other diets considered less efficient, viz. Mytilus edulis testis (MT) and Artemia (AR).Acceptability of all diets attained 100% within 10 min of feeding as revealed by observation through the semitransparent cuticle of the larvae. Histological examination of larvae that ingested comparable amounts of food revealed pronounced variation in the absorption of lipids and carbohydrates by the midgut gland cells (AR〈MT≤MO+ARp〈MO), in the size and ultrastructure of the midgut gland epithelial cells (AR〈MT〈MO+AR〈MO), in the number, size, and electron-dense body content of the haemocytes (AR〈MT≤MO+ARp〈MO), and in the size of cells lining the midgut gland tubules (AR≤MT≤MO+AR〈MO). Growth and survival followed the order MT≤AR〈MO+AR≤MO with maximum survival rates around 25–35% on the more efficient diets. Thus, phyllosoma fed on each diet presented a distinctive set of histological characteristics. Moreover, histological variation between diets was detected earlier than, and yet correlated strongly with, the results on growth and survival. This suggests that histological criteria constitute a practical means for the preliminary assessment of the acceptability and nutritional value of diets for the Japanese spiny lobster.
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  • 7
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Comparative Biochemistry and Physiology -- Part A: Physiology 107 (1994), S. 161-169 
    ISSN: 0300-9629
    Keywords: Misgurnus anguillicaudatus ; Olfaction ; PGF"2"α ; Pheromone ; Prostaglandins ; Sexual behavior ; sex pheromones
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Aquaculture 43 (1984), S. 243-257 
    ISSN: 0044-8486
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Aquaculture 116 (1993), S. 199-217 
    ISSN: 0044-8486
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Aquaculture 126 (1994), S. 61-71 
    ISSN: 0044-8486
    Keywords: Foregut ; Mouthparts ; Organic development ; Ranina ranina
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
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