The biosphere extends above and below the surface of the Earth, wherever there are living ecosystems. A fishing technique involving dragging heavy nets across the sea floor to catch bottom-dwelling fish. Results in severe changes to the sea floor, a high rate of bycatch, and loss of biodiversity. Bycatch includes other species of fish or shellfish, marine mammals, birds, turtles, and specimens of the target species which are below the legal size or otherwise prohibited. The area of land within 100 km the ocean and the area of ocean near the land.
Coastal waters support critical habitat and nurseries for a vast number of important marine species.
Some species are less able to adapt than others to changes in their habitat, and thus more vulnerable to the effects of human activity. An ecological community, including the biological inhabitants, and the environment in which they live, and encompassing the interactions among them which permit the system to function and to sustain life. The area where a river meets the ocean, which may be a widening of the river where its current is met by the tides, or an arm of the sea which extends inland. The total number of genes for a given breeding population makes up its gene pool. A large gene pool is genetically diverse, and therefore more likely to be healthy and robust.