Predatory fish 5 Letters
More than 90% of all top marine predators have disappeared from the oceans. —Myers et al. 2007; MacKenzie et al. 2009
“It appears that ecosystems such as Caribbean coral reefs need sharks to ensure the stability of the entire system.” –Enric Sala, Scripps Institution of Oceanography
Predator loss releases prey populations from both the pressure and risk of predation. In both marine and terrestrial ecosystems, predator removal can cause a potentially irreversible cascade of complex knock-on effects that destabilise food-webs and the marine environment as a whole.
Predators, such as sharks, tuna and billfish, have substantial influence on the structure and function of ecological systems, both directly by regulating prey populations and indirectly through the interactions between their prey and other members of the ecosystem. These indirect effects that occur further down the food-web are referred to as trophic cascades.
Marine predators are experiencing cataclysmic declines worldwide: it is estimated that in excess of 90% of all marine predators have already been lost from the oceans, including tuna, billfish, swordfish and sharks. This is almost entirely due to overfishing, but other factors also contribute. For instance it is estimated that 96.1% of all threats posed to shark populations stem from fishing (57.9% by-catch, 31.7% directed commercial fishing, 5.8% artisanal and 0.7% recreational), with habitat destruction and pollution comprising 2.9% and 0.4% of threats respectively. Soaring demand for sharks in Asian markets is accelerating these declines in shark populations, and it remains largely uncertain just how severe the knock on effects will be.“Soaring demand for sharks in Asian markets is accelerating these declines in shark populations.
Sharks are found in nearly all ocean habitats and form many connections within food-webs due to their high mobility and varied diets. Something that makes sharks of potentially greater influence on food-web dynamics than other marine predators is their ability to consume larger prey than bony fish of similar size (since most sharks can extend their jaws and ‘saw’ with their teeth), and large megafauna (eg. turtles, marine mammals and other elasmobranchs) often have sharks as their major or only predators.
Predatory Pike (Black - Reverse Image - Large) Decal/Sticker - Freshwater Fish Collection
Sports (Express Yourself Products)
That is true - predatory fish and salmon2005-06-29 10:25:50 by ?!?
Especially, though typically mercury levels are not really high enough to cause alarm (unless you follow the sensationalizing press).
Not too long ago the EPA did a survey of US citizens and sent scientists the same set of questions - the public prioritized Superfund sites above anything else as the most significant environmental health threat. The scientists put that at the bottom of the list - and made air quality and food contamination by pesticides and other additives a tie for number 1.
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