Invertebrate survey

Part 1 book "Fisheries management - A manual for still water coarse fisheries" includes content: Introduction; ecology of lakes, bacteria; plants; invertebrates; fish; disease causing organisms; mammals and birds; developing and preparing a fishery; the construction of a still water fishery; fish stock assessment; stock manipulation; invertebrate survey; control of water quality.

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Oceans provide enormous and diverse space for marine life. Invertebrates are conspicuous inhabitants in certain zones such as the intertidal; many are soft- bodied, relatively immobile and lack obvious physical defenses. These animals frequently have evolved chemical defenses against predators and overgrowth by fouling organisms. Marine animals may accumulate and use a variety of toxins from prey organisms and from symbiotic microorganisms for their own purposes. Thus, toxic animals are particularly abundant in the oceans.

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Several attempts have been made to analyze the impacts of air pollution on wildlife . More recently, research for WWF has assessed the impacts on wildlife through a literature survey which identified effects on 1,300 species, including 11 mammals, 29 birds, 10 amphibians, 398 higher plants, 305 fungi, 238 lichens and 65 invertebrates, providing the most detailed survey to date 7 . In general, the studies have concentrated on either specific ecosystems, or individual groups of plants and animals.

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Only about 20% of all extinctions occurred during mass extinctions. The other 80% are known as background extinctions. For most individual species, scientists don’t know the precise cause of extinction. But scientists can gather clues in the broad patterns of extinctions formed by thousands of species. In 2008, Jonathan Payne and Seth Finnegan, two paleontologists at Stanford Uni- versity, surveyed 227,229 fossils of marine invertebrates from about 520 million years ago to 20 million years ago.

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