Publish Paper On Effects Of Fisheries On
Continental Slope And Deep-Sea Ecosystems
Current Status of Accomplishment or Milestone: The paper, "Continental Slope and Deep-Sea Fisheries: Implications for a Fragile Ecosystem" was published in the ICES Journal of Marine Science.
Background: Deepwater commercially-exploited species generally exhibit life history strategies characterized by extreme longevity, late age of maturity, low growth, low fecundity and high recruitment variability. These traits are markedly different from most shallow-water species. Many of these species aggregate on restricted topographic features, such as seamounts. As a consequence, they are notably unproductive, highly vulnerable to overfishing and potentially have little resilience to overexploitation. This paper was developed as a review for presentation at the ICES/SCOR Symposium on Ecosystem Impacts of Fishing held in Montpellier, France, in 1999, and was published in the proceedings volume by an international group of co-authors. The lead author just completed a senior NRC Associateship at PFEL and the second author is PFEL staff.
Purpose of Activity/Goal of Project: The purpose was to examine how deepwater fisheries impact marine ecosystems. Since 1960, deepwater fisheries have contributed 600,000 - 1,000,000 MT annually to global marine fish landings. Underlying this overall apparent stability is the "boom and bust" cycle that has characterized many individual deepwater fisheries. The accumulated biomass of previously unfished deepwater stocks are typically fished down, often within 5-10 years, to the point of commercial extinction or very low sustainable levels. Most deepwater fisheries are today overfished or in danger of depletion. The paper describes the risks associated with these deep water fisheries.
Description of Accomplishment and Significant Results: The manuscript addresses the long-term ecological implications of depleting commercially-fished species, generally dominant at mid- to upper trophic levels, from deep-sea environments. In general, the risks to population viability of reduced stock size and age structure, the potential for species replacement, and the impacts on prey and predator populations are not known. However, deepwater trawl fisheries have been shown to have potentially severe impacts on the benthic fauna of seamounts, where deepwater fishes aggregate. This fauna, dominated by suspension feeders, such as corals, is typically restricted to the seamount environment and is characterized by high levels of endemism, which suggests limited reproductive dispersal. The ability of the benthic community to recover, following its removal by trawling, is not known.
Significance of Accomplishment (e.g., to the Center, to Management, and to NMFS Strategic plan Goals): Stewardship of the marine environment and understanding how fisheries themselves impact essential fish habitat are important objectives in the strategic plan. This paper pays attention to habitats were relatively little is known and provides a concise summary of the kinds of impacts involved in deep-sea fisheries.
Problems: None
Key Contact: George Boehlert (831-648-8515; George.Boehlert@noaa.gov).