Status of deepwater fisheries

The deepwater fisheries are becoming increasingly contentious for several reasons.

First, the "fishing-down" phase has ended, or even been overshot, for most stocks. Most deepwater fisheries began in earnest in the early 1980s, and at that time, a decision was made to fish them down to the average biomass associated with maximum sustainable yield (Bmsy) at a reasonably rapid rate, and then to reduce fishing pressure and maintain biomass at the average Bmsy indefinitely.

For deepwater species, estimates of Bmsy are usually in the range of 25-30% of the unfished biomass. For some stocks, the targets have been overshot – substantially so for Challenger orange roughy, which was estimated to be at about 3% of the unfished level when it was closed in 2000, and for Puysegur orange roughy, estimated to be at about 7% of the unfished level when it was closed in 1998. Some environmental NGOs claim that successive "fishing down" of deepwater stocks represents an example of "serial depletion" of natural resources, rather than recognising it as a deliberate fisheries management strategy.

Secondly, to date there has been inadequate research to accurately determine the long-term sustainable yield from deepwater stocks. There is therefore, still debate about the appropriate levels at which the stocks should be fished.

Thirdly, deepwater trawling tends to disturb the bottom fauna, including several species of extremely long-lived, slow growing corals. As a result, there are increasing requests to close areas completely to this gear type.