Sustaining Marine Fisheries (1999) / Chapter Skim
Currently Skimming:
2 Current Status of Marine Fisheries
2 Current Status of Marine Fisheries
Pages 19-35
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 19... ...
fisheries, the assessments -- corroborated by many kinds 1Estimates of utilization, according to the National Marine Fisheries Service's terminology (1993, 1996b) , are based on the concept of long-term potential yield (LTPY)
|
From page 20... ...
Although thousands of freshwater and marine fish and shellfish species are used globally, a relatively small number of these species provide the major fraction of the global marine catch. The 10 marine species that provided the greatest catch in 1993 accounted for 35 percent of the commercial marine catch (Figure 2-1, FAO 1996b)
|
From page 21... ...
of world fish production was used for animal feed -- including feed for mariculture -- and other products that do not contribute directly to the human food supply in 1995. In addition to fish that are caught and processed, a substantial number of fish and other organisms are caught and discarded -- usually dead -- at sea.
|
From page 22... ...
Production includes aquaculture but represents catch for most marine species. Source: Redrawn from FAO (1996b)
|
From page 23... ...
of about 80 million t, similar to catches that have been achieved in recent years and to recent FAO assessments. Maximum potential global marine fisheries yield has also been estimated by Schaefer (200 million t, 1965)
|
From page 24... ...
Satellite and in situ measurements of phytoplankton concentrations and in situ measurements of nutrients, water temperature, irradiance, and primary production allow estimates of the primary production of the global ocean, as well as regional estimates. An upper limit to the ocean's potential fisheries yield has been estimated many times by applying knowledge of the amount and location of global primary production, trophic level of the catch, and the transfer efficiency of biomass among trophic levels.
|
From page 25... ...
. Another line of evidence suggesting that global marine catch might not increase, even by fishing at progressively lower trophic levels, is provided by analyzing changes in the mean trophic level of marine fishery landings.
|
From page 26... ...
. Figure 2-4 also shows significant declines in the average trophic level of fish catches from the 1950s for the northeast Atlantic and from the 1970s for the northwest Atlantic.
|
From page 27... ...
waters; and cited domestic demand for shark meat; wasteful fisheries practices, especially discarded bycatch of sharks; irrational dread; and an increasing global demand for shark fins as major factors contributing to excess fishing mortality of sharks. In addition, unexploited fish populations that are long lived and slow growing cannot support high exploitation rates, unlike populations of faster-growing, short-lived species.
|
From page 28... ...
Their analysis indicates that catch is higher than the maximum sustainable yield of world fisheries and that fishing capacity is too large to be economically efficient. The decline in the per-ton catch rate of fishing vessels also indicates an economic problem, although lower catches have probably been partially offset by price increases.
|
From page 29... ...
, there are more than 17 million marine recreational fishers, who in recent years made more than 66 million fishing trips per year, caught about 360 million fish, and spent $25.3 billion per year on 6This number includes the weight of the meat but not the shells of shellfish. FAO statistics usually include the weight of the shells also.
|
From page 30... ...
The allocation of available marine fisheries resources between commercial and recreational sectors is a major issue for regional fishery management councils and in the political arena. Some of the disputes and the differences -- and occasional agreements -- between commercial and recreational fishers are described in almost every issue of National Fisherman and Saltwater Sportsman; for a discussion of net bans, for example, see the August 1996 issue of National Fisherman.
|
From page 31... ...
Indigenous People's Fisheries Indigenous people's fisheries are a minor part of total catches but are particularly important in cultural and social terms. Indigenous marine fisheries in the United States -- primarily in Washington, Oregon, California (NRC 1996b)
|
From page 32... ...
fisheries would need to be fished more heavily, but, more importantly, fishing on overutilized stocks, bycatch, and unaccounted mortality will need to be reduced so that stocks can rebuild. The estimated long-term potential yield and maximum sustainable-yield levels can be used as reference points to help guide the sustainable development and prosecution of fisheries or the rebuilding of marine fish stocks that have been overfished.
|
From page 33... ...
This overfishing occurred despite reasonably conservative target fishing mortalities; the problem was largely due to systematic errors in stock assessments exacerbated by unreported (illegal) discarding of small fish and perhaps unreported catches, and later to a failure of management to respond quickly to corrected assessments.
|
From page 34... ...
CAFSAC concluded that the northern cod stock was in fact substantially smaller than previously believed, a view confirmed by an independent Northern Cod Review Panel (Canada 1990) , which estimated that the actual fishing mortality rates had been at least double those projected in the Canadian management strategy (Canada 1990, p.
|
From page 35... ...
. CONCLUSIONS Global marine fish catch is at or near its sustainable limit.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.