A study published in the academic journal Science earlier this week highlighted that expanding ocean-based industry is taking a larger and larger toll on marine life.
The last few decades have seen the establishment industrialized fishing, super trawlers, deep seabed exploitation and aquaculture, dramatically increasing the human impact on the oceans. The trend is increasing rapidly and seems to be on the same course as humankind saw in the 19th and early 20th centuries. Some are calling it the “industrial revolution of the oceans” and warn that the negative ecological impact could be severe.
Statements from study authors
“We have driven cod stocks down to unfishable levels, certain shark species have crashed by [more than] 90 percent, we are now wringing our hands about bluefin tuna declines in both the Atlantic and Pacific,” lead author Douglas McCauley from the University of California Santa Barbara explained to mongabay.com in an interview. “We see these sorts of headlines constantly sprinkled across the news.”
“What is easy to forget as we lament these truly depressing numerical declines in marine fauna is that, relative to land, the course of marine defaunation has involved relatively few outright species extinctions,” McCauley continued.
“There are factory farms in the sea, and cattle-ranch style feed lots for tuna. Shrimp farms are eating up mangroves with the same appetite with which terrestrial farming consumed native prairies and forest,” pointed out co-author Steve Palumbi from Stanford University. “Stakes for seafloor mining claims are being pursued with gold rush-like fervor. Three hundred-ton ocean mining machines and 750 foot fishing boats are now rolling off the assembly line to do this work.”
More on marine life extinctions
According to the International Union for Conservation of Nature at least 15 marine animals have been driven to extinction by humans over the last five centuries, including the great auk, Stellar’s sea cow, and the Caribbean monk seal. On the other hand, the IUCN notes 514 extinctions of land-based animals over that 500 years, highlighting a much greater extinction crisis on land.
The study hypothesizes that extinctions have likely been rarer in the oceans because humans have had less relative impact, but also because marine life “tends to be more widespread, exhibit less endemism, and have higher dispersal.” Of note, the majority of land extinctions have happened on islands, where species literally have no-where to go.
McCauley, however, emphasized that the 15 formally recognized marine extinctions are “an absolute minimum estimate.”