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.

Maladaptive changes in multiple traits caused by fishing: impediments to population recovery.

Abstract: Some overharvested fish populations fail to recover even after considerable reductions in fishing pressure. The reasons are unclear but may involve genetic changes in life history traits that are detrimental to population growth when natural environmental factors prevail. We empirically modelled this process by subjecting populations of a harvested marine fish, the Atlantic silverside, to experimental size-biased fishing regimes over five generations and then measured correlated responses across multiple traits. Populations where large fish were selectively harvested (as in most fisheries) displayed substantial declines in fecundity, egg volume, larval size at hatch, larval viability, larval growth rates, food consumption rate and conversion efficiency, vertebral number, and willingness to forage. These genetically based changes in numerous traits generally reduce the capacity for population recovery.

Yet another review of marine reserves as reef fishery management tools

Abstract: [Extract] The term "marine reserves" is defined in this chapter to simply mean "no-fishing" areas in the marine environment, that is, areas permanently closed to fishing. The goal in this chapter is to review some of the major issues of marine reserves as reef fisheries management tools. Other benefits of marine reserves, including maintenance of biodiversity and ecosystem structure and enhanced tourism, have been reviewed many times elsewhere (Table 1). Marine reserves are not being advocated here as the only, or even the optimum, method of reef fisheries management. In fact, it is vital to stress from the outset that other forms of fisheries and habitat management should be encouraged and attempted in areas open to fishing. In addition, in many developing nations, managing fisheries on coral reefs requires that the number of fishers be reduced considerably (Munro and Williams, 1985; Russ, 1991; Munro, 1996). Without such measures as finding alternative livelihoods for fishers and reducing rates of human population growth, most attempts at managing reef fisheries will probably be futile in many developing nations. In the past decade the topic of marine reserves as potential fisheries management tools has produced a burgeoning literature (Tables 1 and 2). There are at least two major reasons for this. First, scientists working in developing nations and/or on the management of coral reef fisheries (e.g., A. C. Alcala, J. A. Bohnsack, G. E. Davis, T. R. McClanahan, N. V. C. Polunin, and C. M. Roberts) have realized that there are probably few other viable management alternatives. In such situations it is almost socially immoral to try to impose fishing effort or catch restrictions on subsistence and artisanal fishers. You cannot tell a fisher in a developing nation ttlat they must throw a fish back into the ocean because it is too small, or that they must catch only four fish per day when they have eight family members to feed. Second, traditional fisheries management (effort, catch controls) has generally failed to prevent massive overfishing globally. The dismal state of most of 20 stocks of cod in the North Atlantic, exploited by the highly developed nations of Canada, the United States, and Europe, are good examples of this (Myers et al., 1996). Marine reserves are now seen as an insurance policy against such management failures, something Jim Bohnsack was advocating for reef fisheries a decade ago [Plan Development Team (PDT), 1990].

The Spatial Expansion and Ecological Footprint of Fisheries (1950 to Present)

Abstract: Using estimates of the primary production required (PPR) to support fisheries catches (a measure of the footprint of fishing), we analyzed the geographical expansion of the global marine fisheries from 1950 to 2005. We used multiple threshold levels of PPR as percentage of local primary production to define ‘fisheries exploitation’ and applied them to the global dataset of spatially-explicit marine fisheries catches. This approach enabled us to assign exploitation status across a 0.5° latitude/longitude ocean grid system and trace the change in their status over the 56-year time period. This result highlights the global scale expansion in marine fisheries, from the coastal waters off North Atlantic and West Pacific to the waters in the Southern Hemisphere and into the high seas. The southward expansion of fisheries occurred at a rate of almost one degree latitude per year, with the greatest period of expansion occurring in the 1980s and early 1990s. By the mid 1990s, a third of the world's ocean, and two-thirds of continental shelves, were exploited at a level where PPR of fisheries exceed 10% of PP, leaving only unproductive waters of high seas, and relatively inaccessible waters in the Arctic and Antarctic as the last remaining ‘frontiers.’ The growth in marine fisheries catches for more than half a century was only made possible through exploitation of new fishing grounds. Their rapidly diminishing number indicates a global limit to growth and highlights the urgent need for a transition to sustainable fishing through reduction of PPR.