15 research outputs found

    Life Cycles in Marine Ornamental Species : Fishes as a Case Study

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    27 pagesMarine ornamental fish show a great variety of sexual patterns that are the result of specific evolutionary selections and environmental adaptation. Most of the species can be divided into pelagic and demersal spawners. Pelagic spawners usually release gametes in the water column at dusk while demersal spawners have adhesive embryos and parental care. These two modes of reproduction show several differences and specificities, and are fully analyzed in the present chapter. This information is fundamental to the selection of the appropriate species to culturePeer Reviewe

    Experimental analysis of some factors affecting parental expenditure and investment in Gasterosteus aculeatus (Gasterosteidae)

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    Parental investment is the cost of providing parental care. Parental investment was measured in the paternal stickleback, Gasterosteus aculeatus, by comparing future survival (measured indirectly as energy content of the body) and growth of parental and non-parental males. The time taken by parental males to renest was also measured. Male energy content was unaffected after a single parental cycle and no difference in growth rate was detected. Re-nesting was delayed. The effect of stressing parental males by exposing them to potential predators of their offspring and reducing their ration level, was also investigated. Stressed males had reduced energy contents in comparison with unstressed parental males. The time taken by stressed males to re-nest was unaffected. Males on low rations did not fan significantly less than well-fed males. Males exposed to brood predators did fan significantly less than parental males not exposed to brood predators, but the former did spend nearly 60% of their time attacking the predators when present.</p
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