Today (18th June), a long item was posted on the BBC news web-site titled ‘Shortages: Fish on the slide’.
‘… In the first of a series of five essays on declining global resources, the BBC’s Environment Analyst Roger Harrabin looks at the depletion of fish stocks.
The sea exemplifies the world’s on-going failure to govern shared natural resources.
There’s widespread agreement among nations on the need to conserve fish stocks but often disagreement on the details of how to do it.
And the need for unanimity in the UN process consistently allows a handful of countries to put the short-term interests of fishing crews before the fish stocks themselves.
It all means that globally about 85% of stocks are said to be fully exploited, over-exploited, depleted or slowly recovering.
Through the lens of history the depletion of fisheries looks even worse.
Using data from 1889, researchers assessed catches of bottom-feeding fish like cod, plaice and sole in England and Wales.
They calculated that over 118 years of industrial fishing, the productivity of this fishery dropped by 94%. Not to 94% but by 94%.
Anyone with a snorkel and mask – and a tolerance to cold water – can attest that much of the sea bed resembles a desert.
The year of Peak Ocean Fish was 1996. Crews hauled in 87.7 million tonnes of wriggling protein.
The total sea catch has since fallen to about 80 million tonnes and stabilised.
Tuna, the world’s favourite, has declined in the Atlantic since 1993.
Catches of cod in the North-East Atlantic have been tumbling since the late 1960s.
The total catch is being deceptively bolstered by unloved species like blue whiting and sandeels.
Meanwhile fishermen are hunting farther from home for new favourites, using methods like bottom trawling where the ocean floor is scraped clean of life, and long-lining where hooks strung off lines often haul in by-catch that beggars comprehension.
Take the longline fishery for mahi mahi in Costa Rica. Its collateral damage over a decade included 402 silky sharks, 625 stingrays and 1348 olive ridley turtles.
Turtles of course eat jellyfish, an increasing scourge of the seas.
In some areas nine out of ten large sharks have been killed. Callum Roberts, author of the excellent “Ocean of Life”, says we’re tugging blindly at the web of life in the sea.
Big sharks eat cownose rays and, without their predators, the rays in US waters have been free to gorge on the scallops that adorn the tables of top restaurants.
Fishermen are now muscling into the icy waters of the Southern Ocean in an increasingly desperate search for new stocks to feed a world population that’s growing and getting richer.
And our impact on fish stocks isn’t just through nets and lines …
Many of the world’s great rivers carry so much nutrient run-off from farms that the seas by the river mouths are virtually biologically dead.
The coral reefs and mangroves which serve as nurseries for fish in the tropics are being eroded by development, pollution and silt.
Predator fish accumulate man-made chemicals in their bodies passed up through the food chain – polychlorinated biphenyls, flame retardants, endocrine disrupters.
Fish distribution is being changed as the ocean warms with human-induced climate change.
And the CO2 emissions that warm the planet are also dissolving into the ocean and making it less alkaline – acid ocean syndrome. The change is chemically minuscule but historically huge.
There’s much uncertainty how sealife will react but some scientists forecast that coral reefs in their current form won’t survive. Studies suggest that pteropods – tiny swimming snails – will be badly hit because they need alkaline water to make their shells …
But the picture is not totally bleak. The first Rio Earth Summit in 1992 called for nations to find ways to conserve fish stocks and prevent international conflicts over fishing on the high seas …’
Read the item in full and view images and graphics at www.bbc.co.uk/news/science-environment-18353964
[Vegans say abandon the exploitation, abuse and slaughter of all animals, including marine animals (sea fish and shellfish), and abandon the production and consumption of all animal products.]