Sharks

Coming in many different shapes, colors, and sizes, sharks are some of the most incredible fish in the sea. They differ from bony fish in numerous ways: their skeleton is made of cartilage instead of bone, they five to seven pairs of gill slits instead of a bony fish’s single pair, and they have rigid fins while bony fishes have flexible fins.

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The more than 400 species of sharks are mysterious, yet misunderstood. Unfortunately, their populations are plummeting due to overfishing of sharks for food, including for their valuable fins. Sharks have very slow growth and reproductive rates, which means depleted populations are slow to recover. The loss of these top predators would throw the delicate ecosystem balance into disorder. Other threats include habitat alteration, damage and loss from coastal development, pollution and the impact of fisheries on the seabed and prey species. The 2007 documentary, Sharkwater, exposed how sharks are being hunted to extinction.

Popular misconceptions
A popular myth is that sharks are immune to disease and Cancer this is not scientifically supported. Sharks may get cancer. Both diseases and parasites affect sharks. The evidence that sharks are at least resistant to cancer and disease is mostly anecdotal and there have been few, if any, scientific or statitstical studies that show sharks to have heightened immunity to disease. Other apparently false claims are that fins prevent Cancer and treat osteoarthiritus. No scientific proof supports these claims; at least one study has shown shark cartilage of no value in cancer treatment.