A third of shark and ray species have been overfished to near extinction, according to an eight-year scientific study.
Dulvy said: “Our study reveals an increasingly grim reality, with these species now making up one of the most threatened vertebrate lineages, second only to the amphibians in the risks they face." Sharks, rays, and chimaeras are vulnerable to overfishing because they grow slowly and produce few young. It has beenthat 100 million sharks are killed by humans every year, overwhelming their slow reproductive capacity. Industrial fishing was a “key threat” to chondrichthyans, either on its own or in combination with other fisheries, the authors said.
Chondrichthyans have survived at least five mass extinctions in their 420 million-year history, according to the report. But, at least three species are now critically endangered and possibly extinct. The Java stingaree has not been recorded since 1868, the Red Sea torpedo ray since 1898, and the South China Sea’s lost shark has not been seen since 1934. Their disappearance would be the first time in the world that marine species have become extinct because of overfishing.
The experts, mainly from the IUCN shark specialist group, assessed 1,199 species and classified 391 in the IUCN threatened categories of critically endangered , endangered , or vulnerable .
You think they may just be hiding in deeper waters? They are not dumb.
In the long run every species goes extinct. Guaranteed!
Speaking of the numbers of species, how many species will be needed for a *totally* self-sufficient Mars city? How many unneeded species could a Mars city support? Could a Mars city have sloths, anteaters, geckoes, and salamanders? Pythons? Pandas? Those giant stink flowers?