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#fish species

2 public questions tagged with this topic.

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 scales and therefore do not express the same causal relationship. A niche is the multidimensional set of abiotic conditions, resources, and biotic relationships under which a population can persist. The fundamental niche reflects physiological and resource limits, while the realized niche is modified by competitors, consumers, mutualists, and dispersal barriers. The cited framing is therefore most useful when treated as a conditional biological claim, with assumptions about scale and environmental context kept explicit.

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

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 numbers remains system-dependent. Standardised sampling and contamination controls are essential because airborne fibres can enter samples during collection and laboratory processing. Particle size, shape, polymer type, weathering state, and associated chemicals all influence uptake and biological response, so microplastics are not a uniform toxicant. Laboratory effects must be interpreted alongside environmentally realistic concentrations, while field detection demonstrates exposure but does not alone prove causation. Prevention requires reducing unnecessary plastic use, improving collection and recycling, controlling lost fishing gear, and limiting releases of fibres and tyre-wear particles.

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