Scientists calculate our planet supports 230,000 marine species. That's a lot. That's the good news. The bad news is that the scientists who logged all these species found, in the course of their research, that many fish populations have plummeted by 90-95% of their normal numbers. From The Guardian:
"Published today, a 10-year study of the diversity, distribution and abundance of life in the world's oceans attempts just that. The Census of Marine Life, which hopes to paint a baseline of marine life, estimates there are more than 230,000 species in our oceans.
The surveys have also highlighted major areas of concern for conservationists. "In every region, they've got the same story of a major collapse of what were usually very abundant fish stocks or crabs or crustaceans that are now only 5-10% of what they used to be," said Mark Costello of the Leigh Marine Laboratory, University of Auckland in New Zealand. "These are largely due to over-harvesting and poor management of those fisheries. That's probably the biggest and most consistent threat to marine biodiversity around the world."
The main threats to date include overfishing, degraded habitats, pollution and the arrival of invasive species. But more problems are around the corner: rising water temperatures and acidification thanks to climate change and the growth in areas of the ocean that are low in oxygen and, therefore, unable to support life."
When it comes to mankind, once again it's the poorest and most vulnerable who take it in the neck from collapsing fish stocks. The world's poor tend to rely on fish as their main, often only source of animal protein. But poor people can't afford the expensive technology the rich people have for intensively harvesting declining fish stocks. And once those fish are gone, well.... we move on to keep fishing down the food chain while the poor people get to enjoy their empty waters. Neat, eh?