Fishing

About: Fishing is a research topic. Over the lifetime, 26543 publications have been published within this topic receiving 455552 citations. The topic is also known as: angling.

Minimizing the impact of fishing

Abstract: Minimizing the impact of fishing is an explicit goal in international agreements as well as in regional directives and national laws. To assist in practical implementation, three simple rules for fisheries management are proposed in this study: 1) take less than nature by ensuring that mortality caused by fishing is less than the natural rate of mortality; 2) maintain population sizes above half of natural abundance, at levels where populations are still likely to be able to fulfil their ecosystem functions as prey or predator; and 3) let fish grow and reproduce, by adjusting the size at first capture such that the mean length in the catch equals the length where the biomass of an unexploited cohort would be maximum (Lopt). For rule 3), the basic equations describing growth in age-structured populations are re-examined and a new optimum length for first capture (Lc_opt) is established. For a given rate of fishing mortality, Lc_opt keeps catch and profit near their theoretical optima while maintaining large population sizes. Application of the three rules would not only minimize the impact of fishing on commercial species, it may also achieve several goals of ecosystem-based fisheries management, such as rebuilding the biomass of prey and predator species in the system and reducing collateral impact of fishing, because with more fish in the water, shorter duration of gear deployment is needed for a given catch. The study also addresses typical criticisms of these common sense rules for fisheries management.

Why do fishers fish where they fish? Using the ideal free distribution to understand the behaviour of artisanal reef fishers

Abstract: We used the theory of the ideal free distribution (IFD) as a framework to understand the mechanisms underlying fishing site selection by Anguillian artisanal fishers exploiting shallow-water coral reefs. Contrary to the predictions of IFD, fishers did not distribute themselves so that average reward was equal among fishers using different fishing methods or among fishers using the same method. In addition, fishing pressure did not increase with resource availability. Key assumptions of the IFD were not met. The distribution of Anguillian fishers was not "ideal" because lack of knowledge prevented fishers from choosing fishing grounds with the greatest rewards. Not all fishers sought to maximise profit. In addition, all fishers were not "free" to distribute themselves among reefs owing to variation in social, economic, and physical characteristics of fishers that constrained fisher movements and ability to extract resources. This study shows that as a null model the IFD is useful to frame studies designed ...

Incidental capture of seabirds in the New Zealand subantarctic squid trawl fishery, 1990

Abstract: Fisheries observers recorded incidental capture of seabirds during 338 days on Soviet squid trawlers in New Zealand subantarctic shelf waters around the Snares and Auckland Islands in 1990. Seven species were recorded entangled in fishing gear, including very high numbers of breeding adult White-capped Albatrosses Diomedea cauta steadi. The actual level of White-capped Albatross mortality was estimated at 2,300 birds in 1990, and is not considered sustainable. Nearly all albatrosses were killed by collision with the netsonde monitor cable. In New Zealand waters this equipment is carried only by Soviet trawlers, and is considered obsolete. Replacement of this cable by discrete netsonde transducers on Soviet trawlers should be a global seabird conservation priority.