“Sharks contribute to healthy marine ecosystems.”
Shark research is a relatively young field in science and there is still a lot of missing information about even the basic biology of many shark species. So topics as complex as the effect of declining sharks on their surrounding ecosystem are extremely difficult to investigate.
There seems to be, however, consensus about one thing. As large predators, sharks are key contributors to healthy marine ecosystems, adding to their biodiversity and durable functioning. The serious decline of sharks could lead to unpredictable effects on the ecosystem, which may include a sudden rise in their prey species. This, in turn, could lead to cascading effects on other species, eventually changing the entire system. To what extent this would happen depends on a multitude of factors, including the type of ecosystem, the type of species, structure of the food web, and external factors, such as exploitation and environmental factors. Research suggest that particularly larger sharks that feed higher up in the food chain and species associated to coral reefs have a critical impact on their surroundings.
And sharks influence the health of the seas in other ways, too. For instance, migratory sharks were found to couple the energy cycles between otherwise closed ecosystems. By eating in one place and releasing their waste in another, they distribute organic substances and chemicals. Another finding was that large predators like sharks help prevent climate change by regulating the storage of underwater carbon. They do this by keeping populations of herbivores and organisms that disturb soils in check.
Simply put it in black and white, shark conservation is important for the entire ecosystem because many species are currently declining at a serious rate and we simply have no clear idea about what would happen if a species would be lost. And the available evidence suggests that we do not want to find out.
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By Linda Planthof