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  • 1
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Protein and energy are two of the main limiting factors for sea urchin growth. However, the requirement of daily protein and energy to maximize gonadal production is still unknown. Paracentrotus lividus were fed three experimental diets: Ulva lactuca, Gracilaria conferta and a prepared diet for 2 months in the fall of 1999 and spring of 2000. Sea urchins from a laboratory-cultured population of equal age, weight and test diameter were used. Apparent digestibility coefficients (ADC%) for protein and energy, using acid-insoluble ash as a marker, were measured for all experimental diets. Apparent digestibility coefficients for protein was high (〉75%) for all diets. Energy digestibility varied among the diets and was lowest for G. conferta (50–62%). The three diets contained varying digestible protein (DP) to digestible energy (DE) ratios of 25, 26 and 12 mg kJ−1 for U. lactuca, G. conferta and the prepared diet respectively. Digestible protein intake was similar for all treatments, but DE intake was greater for sea urchins fed the prepared diet in both seasons. As a result, the gonad production was significantly higher for urchins fed the prepared diet, suggesting that energy was limiting in the algal diets. Paracentrotus lividus spawned during the spring experiment, resulting in protein loss in all treatments. Protein loss was lowest in the sea urchins fed the prepared diet. Enhanced gonadal growth and gamete development of P. lividus resulted from the higher dietary energy content of the prepared diet.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . A species of Amphidinium bloomed in a mariculture sedimentation pond that was used to grow bivalves near the Gulf of Eilat, Israel. Its overall length averaged 13 μm, the hypocone was 11 μm, and its width was 8μm. It has a ventral ridge. The sulcus begins at the longitudinal flagellar pore and does not project forward in the apex toward the transverse flagellar pore and left margin of the cingulum. The sulcus is a very shallow groove that projects variably about a third of the body length toward the antapex. The cingulum is a deep groove as it circles the cell from the left ventral side to the dorsal side and then becomes very shallow on the right ventral side as it arches posterior toward the longitudinal flagellar pore. Using a modified method for studying dinoflagellate chromosomes in the SEM, we observed 31 chromosomes. The plastid is dorsal and peripheral with 6 ventrally projecting peripheral digital lobes that wrap around the sides of the ventral and posterior nucleus. Amphidinium eilatiensis n. sp. is morphologically closest to Amphidinium carterae and Amphidinium rhynchocephalum, but it does not have the obvious thecal plates or polygonal units described for the former species. Instead, it has a series of spicules, bumps, and ridges on its surface. It differs from A. rhynchocephalum by two morphological characters: surface morphology and gross plastid architecture.The amplified fragments of the rDNA from A. eilatiensis n. sp. isolated from 2 separate sedimentation ponds in Eilat include the 3′-end of the SSU rDNA (about 100 nt), the whole ITS region (ITS1 + 5. 8S + ITS2) and the 5′-end of the LSU rDNA (about 900 nts). The total length of the sequences ranged from 1,460 nt. (A. eilatiensis isolate #1) to 1,461 nts. (A. eilatiensis isolate #2). The latter sequences are identical, the difference in length being due to three insertions. Amphidinium eilatiensis is genetically more closely related to A. carterae than to A. klebsii, with respectively 2. 36% and 6. 93% of sequence divergence.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Environmental biology of fishes 31 (1991), S. 131-138 
    ISSN: 1573-5133
    Keywords: Predator removal ; Prey ; Reef fish community
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Elimination of adult groupers (Cephalopholis spp.) from various reef formations in the Gulf of Aqaba (Red Sea) resulted in replenishment by other predatory fishes of different taxa and only partly (21.6%) by species of the same genus. Three years later, the initial population composition had not been restored. Recolonization by juvenile groupers presumably settling from the plankton was only 11.3%. Censuses of the typical piscine prey of groupers, before and 36 months after the removal of Cephalopholis, showed virtually no change in abundace and species composition.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Environmental biology of fishes 24 (1989), S. 67-73 
    ISSN: 1573-5133
    Keywords: Food selectivity ; Feeding tactics ; Hunting ; Red Sea ; Predatory fishes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis This paper describes a study performed in the Gulf of Aqaba on food selectivity and hunting behaviour of three species of sympatric fish from the genusCephalopholis. These fishes occur in the shallow-water coral habitats of the Red Sea and feed on fishes and invertebrates. Of these,C. argus andC. miniata prefer selected fish species (95 and 86% of their diet respectively), whereasC. hemistiktos consumes more invertebrates (36%) and is less selective with respect to fish species. All three species employ various techniques to catch their prey and in situations where their elected food is absent they readily switch to substitute prey species.
    Type of Medium: Electronic Resource
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