Deep-sea fishing is unsustainable12/09/2011 10:27:16 Scientists find nearly all deep-sea fisheries unsustainable, call for stopping unsustainable fisheries and government subsidies that support them
September 2011. A team of leading marine scientists from around the world is recommending an end to most commercial fishing in the deep sea, the Earth's largest ecosystem. Instead, they recommend fishing in more productive waters nearer to consumers.
In a comprehensive analysis published in the journal Marine Policy, marine ecologists, fisheries biologists, economists, mathematicians and international policy experts show that, with rare exceptions, deep-sea fisheries are unsustainable. The "Sustainability of deep-sea fisheries" study, funded mainly by the Lenfest Ocean Program, comes just before the UN decides whether to continue allowing deep-sea fishing in international waters, which the UN calls "high seas."
Very slow reproductive rates & 4000 year old corals
Life is mostly sparse in the oceans' cold depths, far from the sunlight that fuels photosynthesis. Food is scarce and life processes happen at a slower pace than near the sea surface. Some deep-sea fishes live more than a century; some deep-sea corals can live more than 4,000 years. When bottom trawlers rip life from the depths, animals adapted to life in deep-sea time can't repopulate on human time scales. Powerful fishing technologies are overwhelming them.
The world's worst place to catch fish
"The deep sea is the world's worst place to catch fish" says marine ecologist Dr. Elliott Norse, the study's lead author and President of the Marine Conservation Institute in Bellevue, Washington USA. "Deep-sea fishes are especially vulnerable because they can't repopulate quickly after being overfished."
The deep sea provides less than 1% of the world's seafood. But fishing there, especially bottom trawling, causes profound, lasting damage to fishes and life on the seafloor, such as deep-sea corals, these experts say.
Since the 1970s, when coastal fisheries were overexploited, commercial fishing fleets have moved further offshore and into deeper waters. Some now fish more than a mile deep.
"Because these fish grow slowly and live a long time, they can only sustain a very low rate of fishing," says author Dr. Selina Heppell, a marine fisheries ecologist at Oregon State University. "On the high seas, it is impossible to control or even monitor the amount of fishing that is occurring. The effects on local populations can be devastating."
Orange roughy - Slimehead
The authors document the collapse of many deep-sea fishes around the world, including sharks and orange roughy. Other commercially caught deep-sea fishes include grenadiers (rattails) and blue ling.
"Fifty years ago no one ate orange roughy," said author Dr. Daniel Pauly, a fisheries biologist with the University of British Columbia (UBC). "In fact, it used to be called slimehead, indicating no one ever thought we would eat it. But as we've overfished our coastal species, that changed and so did the name."
Orange roughy take 30 years to reach sexual maturity and can live 125 years. Compared with most coastal fishes, they live in slow-motion. Unfortunately for them and the deep-sea corals they live among, they can no longer hide from industrial fishing.
"Fishing for orange roughy started in New Zealand and grew rapidly through the 1980s and 1990s. However, most of the fisheries were overexploited, and catch levels have either been dramatically reduced or the fisheries closed all together," says author Dr. Malcolm Clark, a New Zealand-based fisheries biologist. "The same pattern has been repeated in Australia, Namibia, the SW Indian Ocean, Chile and Ireland. It demonstrates how vulnerable deep-sea fish species can be to overfishing and potential stock collapse."