Sustainable deep-sea fisheries: an oxymoron?

An FAO publication (Mace & Sissenwine, “Can Deep-Water Fisheries be managed sustainably”) establishes that there are no substantial sustainable deepwater fisheries  (cf. Table 3, page 68).

“Deepwater fisheries have failed to be sustainable (…) This experience clearly points to the need to strictly adhere to the precautionary approach and apply an ecosystem approach”.

Richard Haedrich, Professor Emeritus at Memorial University, Canada, answers a questionnaire from the ‘Deep-sea Fisheries Mission’ following the Grenelle Seas Summit of February 2010:

– Do we know enough about deep-sea fishes in general to manage them rationally?

– R.H: In general the answer is no, not enough is known. What is needed is knowledge of the life history parameters of the fishes involved. A recent study focusing on the North Atlantic, one of the best-known deep ocean areas in the world, found the required data to be almost totally lacking.

In order to resolve the crucial issue of sustainability, BLOOM (with various scientific organizations and other NGOs) organized a workshop, aiming to answer three questions:

  1. Can deep-sea species be fished sustainably?
  2. Are deep-sea fisheries currently sustainable?
  3. If not, what changes are required in the management of deep-sea fisheries to ensure that catches of target and non-target deep-sea species are sustainable?

The researchers concluded that:

“Theoretically, all deep-sea fisheries could have been conducted sustainably.”

“Most commercially important deep-sea fisheries were well underway, and some had even already collapsed, before the details of their population characteristics were known. Historical catch levels were much too high to allow the populations to replenish themselves.

Among the many species of commercial interest that had potential for long-term sustainability, the workshop participants analyzed the fishery for orange roughy. Exploitation of the species in the Atlantic has reduced the stock size to only 30% of what it once was, and even under a “no catch” scenario, it is likely to take over 100 years for the population to recover. Orange roughy is an especially long-lived species, mature females do not spawn until they are older than most other fish, little is known about the early life history of the species, and the fisheries are promulgated on spawning aggregations. Thus, the orange roughy is an example of a species whose population characteristics suggest it could only have been fished sustainably by taking very small proportions of the population, which did not happen in the North Atlantic, and does not seem to be happening in the South Pacific. Instead, the history of the fishery is one of serial depletion of stocks in most areas of the ocean where the species is fished.”

The read the conclusions of the report in full, click here

To read a summary version, click here

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