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#fish species

2 public questions tagged with this topic.

Habitat Niche

Habitat of a fish species can include:

“Biotic and abiotic parameters in a lake” for habitat of a fish species can include. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Habitat describes where an organism occurs; niche additionally describes how it obtains resources and affects or responds to other organisms. Distribution therefore provides evidence about a niche but is not identical to it. The remaining alternatives—“Only water parameters”, “Only food resources”, “Terrestrial ecosystems”—refer to different states, processes, or sca

Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 13

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Applied Ecology

Which environmental toxin is known to feminize fish species?

Synthetic estrogens such as 17alpha-ethinylestradiol can feminise fish by binding estrogen receptors and altering gene expression during gonadal development and adult reproduction. Effects include male vitellogenin production, intersex tissue, reduced sperm production, female-biased phenotypes, and population decline. Testosterone is androgenic rather than estrogenic, while mercury and PCBs have important toxic effects but are not the clearest specific answer. Trophic transfer can occur when predators consume contaminated prey, although evidence for consistent biomagnification of particle numb

Ref: Campbell Biology, Urry et al., 12th Ed., Unit 8 Ecology

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