Ever wondered what kinds of wildlife dominate the world’s seas and oceans? Now there’s an answer, at least in terms of the number of species in different categories. It’s not fish. It’s not mammals. It’s crustaceans!
A mammoth Census of Marine Life has revealed that nearly one-fifth, or 19 percent, of all the marine species known to humans are crustaceans — crabs, lobsters, crayfish, shrimp, krill, barnacles and others far too numerous to mention here. The census didn’t count the actual numbers of animals beneath the waves — that would have been impossible — but it did count up the number of species in 25 marine areas. The aim is to set down a biodiversity baseline for future use.
It took 360 scientists to figure this out. Their findings were posted on Monday in PLoS ONE, an open-source peer-reviewed online scientific journal. An even more fulsome list will be out in October.
For now, there’s plenty of data to chew on: of the 25 marine areas around the world that were examined, Australian and Japanese waters were the most biodiverse, with nearly 33,000 species in each of these locations. The oceans off China, the Mediterranean Sea and the Gulf of Mexico round out the top five most biodiverse marine regions.
After crustaceans, mollusks (like squid, octopus, clams, snails and slugs) rank second in terms of the number of species found in these regions, with 17 percent. Fish, including sharks, make up 12 percent of species. After that, it’s one-celled micro-organisms at 10 percent; algae and other plant-like organisms at 10 percent; segmented worms at 7 percent; sea anemones, corals and jellyfish, 5 percent; flatworms, 3 percent; starfish, brittle stars, sea urchins, sand dollars and sea cucumbers, 3 percent; sponges, 3 percent; mat or “moss animals,” 2 percent; sea squirts, 1 percent.