Fishing techniques

Abstract: The use of fish aggregating devices (FADs) by purse seine fisheries has come under increasing criticism for its potential deleterious impacts on tuna stocks, for high levels of by-catch and threats to the biodiversity of tropical pelagic ecosystems. Here, we review the current state of scientific knowledge of this fishing technique and current management strategies. Our intent is to encourage objective discussion of the topic and highlight areas worthy of future research. We show that catching juvenile tuna around FADs does not necessarily result in overfishing of stocks, although more selective fishing techniques would likely help obtain higher yield. Levels of non-tuna by-catch are comparable to or less than in other commercial tuna fisheries and are primarily comprised of species that are not considered threatened. Accordingly, to minimize impacts on ecosystem balance, there is merit in considering that all species captured in purse seine fisheries (excluding vulnerable species such as turtles and sharks) should be retained, but the consequences of such a measure should be carefully examined before implementation. The take of vulnerable species could be further reduced by introduction of additional mitigation measures, but their potential benefits would be limited without parallel efforts with other gears. Finally, there is no unequivocal empirical evidence that FADs represent an ‘ecological trap’ that inherently disrupts tuna biology although further research should focus on this issue. We encourage RFMOs to expand and improve their FAD management plans. Under appropriate management regimes, FAD fishing could be an ecologically and economically sensible fishing method.

Abstract: Fish from inland waters provide a major source of animal protein, particularly in areas far removed from the sea. The current high demand for fish, and the increased awareness of the role of the environment in supporting human well being, have led to a situation where attitudes to inland water resources are rapidly changing. This change is part of a larger preoccupation for the long-term stability of ecosystems as well as a concern for the capacity of existing freshwater resources to meet human needs. Compiled by Robin Welcomme for the Food and Agriculture Organization of the United Nations, with contributions from several internationally known and respected scientists, this exciting book covers, in depth, the nature of inland waters, the fish populations that live within them, their utilization by fishing industries, and the fishing techniques that these industries use. Comprehensive coverage is also given to evaluation of resources and social and economic issues, management of fisheries and environment, biodiversity and conservation, enhancement, rehabilitation and legislative issues. Fully international in its coverage, "Inland Fisheries" is an essential reference manual for all those involved in inland waterway and fisheries management including fisheries officers, environmental scientists and ecologists, aquatic scientists, those working in rivers and lakes authorities and fish and wildlife departments of governments and universities.

Abstract: Fishery resources are a vital source of food and make valuable economic contributions to the local communities involved in fishery activities along the 850 km stretch of the Tanzania coastline and numerous islands. Small-scale artisanal fishery accounts for the majority of fish catch produced by more than 43 000 fishermen in the country, mainly operating in shallow waters within the continental shelf, using traditional fishing vessels including small boats, dhows, canoes, outrigger canoes and dinghys. Various fishing techniques are applied using uncomplicated passive fishing gears such as basket traps, fence traps, nets as well as different hook and line techniques. Species composition and size of the fish varies with gear type and location. More than 500 species of fish are utilized for food with reef fishes being the most important category including emperors, snappers, sweetlips, parrotfish, surgeonfish, rabbitfish, groupers and goatfish. Most of the fish products are used for subsistence purposes. However, some are exported. Destructive fishing methods such as drag nets and dynamite fishing pose a serious problem as they destroy important habitats for fish and other organisms, and there is a long-term trend of overharvested fishery resources. However, fishing pressure varies within the country as fishery resources are utilized in a sustainable manner in some areas. For this report more than 340 references about Tanzanian fishery and fish ecology were covered. There are many gaps in terms of information needed for successful fishery management regarding both basic and applied research. Most research results have been presented as grey literature (57%) with limited distribution; only one-fifth were scientific publications in international journals.