Recovery Of Fish Stocks Research Articles

Review of mesh measurement methodologies

Many technical measures aimed at the conservation and recovery of fish stocks are based on the implementation of minimum mesh sizes to guarantee a certain level of fishing gear selectivity. At present, different methods are used to measure mesh opening, according to whether the measurement serves fisheries inspection, fisheries research or the manufacturing of netting for fishing nets. At the very least, this causes confusion but can also have more serious consequences such as the criminalization of well intentioned fishermen or the setting of inappropriate mesh size regulations. For example, the measurements made by fishery inspectors using the wedge gauge are generally larger than those made by scientists using the ICES gauge. As a result the cod-ends used by fishermen to satisfy the fishery inspectors will have a selectivity lower than that anticipated by the scientists who provided the advice that informed the relevant legislation. In 1999, owing to the wider range of twines and netting materials used by the fishing industry, ICES established the Study Group on Mesh Measurement Methodology (SGMESH) to refine mesh measurement procedures. At the same time the different stakeholders agreed that there was a need to consider the adoption of a standard mesh measurement method. A major step in the standardization of mesh measurement methodologies was the development of a new standard mesh gauge (2002–2005). In October 2005, it was adopted by ICES as the new standard for mesh measurements and in June 2006 the Northwest Atlantic Fisheries Organization (NAFO) recommended its use for scientific purposes. This review paper critically examines the different mesh measurement methodologies and their related problems, and introduces and describes a new objective mesh gauge (OMEGA) to replace the former less satisfactory gauges. Its adoption will result in researchers, fisheries inspectors and the netting industry using one standard gauge and one set of standard protocols to achieve consistent mesh-size measurements.

A sixteen-country mobilization for sustainable fisheries in the Guinea Current Large Marine Ecosystem

The Guinea Current Large Marine Ecosystem (GCLME) extending from Bissagos Island (Guinea Bissau) in the north to Cabinda (Angola) in the south defines the shared transboundary waters off the coast of western Africa, which embodies some of the major coastal upwelling sub-ecosystems of the world and is an important centre of marine biodiversity and marine food production. The GCLME is characterized by distinctive bathymetry, hydrography, chemistry, and trophodynamics and represents the number 28 Large Marine Ecosystem (LME) ranked among the most productive coastal and offshore waters in the world with rich fishery resources. However, over-exploitation of fisheries, pollution from domestic and industry sources, habitat destruction and poorly planned and managed coastal developments and near-shore activities are resulting in a rapid depletion of the rich fisheries resources and degradation of vulnerable coastal and offshore habitats putting the economies, productivity and health of the populace at risk. Recognizing the urgency of the fisheries decline and the environmental and socio-economic consequences for the region, the 16 countries bordering the ecosystem have mobilized complementary resources to the funding from the Global Environment Facility and United Nations Industrial Development Organization to implement priority management actions agreed in the preliminary Strategic Action Programme for the recovery of depleted fish stocks and restoration of degraded habitats for the advancement of the achievement of the World Summit on Sustainable Development (WSSD) Johannesburg Plan of Implementation targets for recovery of fish stocks.

Recovery of fish stocks in the Seto Inland Sea

The total amount of fisheries’ yield in the Seto Inland Sea in 1999 was 571,000 MT, consisting of 256,000 MT by fishing and 315,000 MT from aquaculture. About 40,000 people engaged in the fishing and aquaculture industries, earned 129 billion yen (1100 million US$) by fishing and 89 billion yen (770 million $US) by aquaculture. The averaged annual catch for the Seto Inland Sea by fishing was 13 MT/km2. Division into time periods in terms of eutrophication levels can be made: before 1960 when red sea bream were abundant with ecological divergence (before eutrophication), from 1960 to 1990 when the biomass of anchovy was large (during eutrophication), and after 1990 when the jellyfishes were abundant (excessive eutrophication or high N:P ratio). The fish production will decrease in the sea of jellyfishes. Actually, the amount of catch was 462,000 MT in 1982 which decreased 265,000 MT in 1993, corresponding to 43% in twelve years, then keeping the same level. A big reduction was seen in the catches of the spotlined sardine, anchovy, Spanish mackerel, tiger puffer, short-necked clam, sea cucumber and others. The tiger puffer and Spanish mackerel were abundant as predators in the sea of anchovy. The biomass of anchovy was at its maximum in 1986 and decreased to less than one third in 1996. The stocks of tiger puffer and Spanish mackerel greatly decreased because of the higher fishing pressure compared to the anchovy stock. The fishing power of individual fisheries targeting on the tiger puffer and Spanish mackerel increased substantially when fishing vessel and fishing gear improved, resulting in an excessive fishing effort. A large quantity of small immature fishes is usually caught in the Seto Inland Sea, resulting in growth and/or recruitment overfishing for many species. Hence, it is necessary to promote management of the fisheries so as not to reduce the fish stocks, and to allow the Seto Inland Sea to return from being a sea of jellyfishes to a sea of anchovy, with decreased eutrophication levels.

Estimates of fishermen's personal discount rate

Most empirical research on personal discount rates (PDRs) relates to individuals purchasing household appliances and inter-temporal choices on monetary transactions. No estimates of PDRs associated with natural resource exploitation were found in the literature and the purpose of this letter is to present estimates of commercial fishermen's PDRs implicit in choices on a hypothetical fish-stock recovery programme. Knowledge of such PDRs are necessary for the design of effective voluntary programmes for fish stock conservation.

Fisheries Laboratory, Lowestoft

ALTHOUGH three members of the staff of the Fisheries Laboratory, Lowestoft, who were acting as coastal fishery officers, succeeded in making scientific observations which have given valuable information on the war-time recovery of fish stocks, all co-ordinated scientific work at the Laboratory was suspended during the War. The Laboratory reopened in September 1945, when ichthyometric work on the chief food fishes and age-composition observations on the North Sea plaice and herring were resumed at the appropriate ports of landing. Plans for work in the waters around the British Isles and in the Arctic fishing grounds are in active preparation. These include the construction of a new laboratory, the building of a large research ship of the type used by the Hull trawler owners for the prolific Arctic fishery, and the conversion for research work in the North Sea of the Admiralty trawler Sir Lancelot, built during the War on the model of a successful commercial type-the Star of Orkney. In the meantime, a 90-ft. motor fishing vessel of a class built by the Admiralty with a view to subsequent use as fishing boats has been borrowed and converted to carry a trawl on the starboard side. This vessel is to be known as the Platessa. While her main task will be to mark large numbers of plaice in the southern North Sea so as to obtain vital information on the yield of the stock at the present rate of fishing, it is also hoped to gain information on the suitability and efficiency of this type of craft as a commercial trawler.