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.

Attraction of wild fish to sea-cage fish farms in the south-western Mediterranean Sea: spatial and short-term temporal variability

Abstract: Aggregations of wild fish were counted around 9 floating sea-cage fish farms along a 300 km stretch of the Spanish coastline in the south-western Mediterranean Sea. Each fish farm cul- tivated Sparus aurata and Dicentrarchus labrax in 6 to 16 floating sea cages between 10 m and 7.4 km from the coast. During September and October 2001, assemblages of fish were counted on 3 separate days at each of 9 farms. Six 5 min rapid visual counts using SCUBA and covering 11 250 m 3 were per- formed within each farm complex and at open water control sites 200 m distant from farms. Abun- dance (52 to 2837× ), biomass (2.8 to 1126 × ) and number of species (1.6 to 14 × ) were greater in fish farm counts than control counts at all locations. Twenty-seven species were recorded at fish farms, with 2 families, Sparidae (12 species) and Carangidae (4 species), being particularly abundant. Over 85% of farm-associated fish were of adult size. Assemblages of wild fish differed greatly between farms separated by 10s to 100s of km, although there was some evidence to suggest that similar assemblages occur at farms separated by 100s of m to several km. Abundance, biomass and number of species differed among fish farms, with all 3 variables negatively correlated with distance of farms from shore and positively correlated with size of farms. Limited variability of wild fish assemblages and abundance of the dominant taxa at each farm among times sampled indicated some degree of temporal stability on a scale of several weeks. Due to the strong aggregative effect of fish farms, pos- sible residence of fishes for periods of weeks to months and the prohibition of fishing within farm leasehold areas, we suggest that coastal sea-cage fish farms may act as small (up to 160 000 m 2 ), pelagic marine protected areas (MPAs). Furthermore, at farms where wild fish are abundant, ecolog- ical interactions that may influence both wild fish stocks and the impact of farms must be considered.

Lagged social-ecological responses to climate and range shifts in fisheries

Abstract: While previous research has documented marine fish and invertebrates shifting poleward in response to warming climates, less is known about the response of fisheries to these changes. By examining fisheries in the northeastern United States over the last four decades of warming temperatures, we show that northward shifts in species distributions were matched by corresponding northward shifts in fisheries. The proportion of warm-water species caught in most states also increased through time. Most importantly, however, fisheries shifted only 10–30 % as much as their target species, and evidence suggested that economic and regulatory constraints played important roles in creating these lags. These lags may lead to overfishing and population declines if not accounted for in fisheries management and climate adaptation. In coupled natural-human systems such as fisheries, human actions play important roles in determining the sustainability of the system and, therefore, future conservation and climate mitigation planning will need to consider not only biophysical changes, but also human responses to these changes and the feedbacks that these responses have on ecosystems.

Fishing amplifies forage fish population collapses

Abstract: Forage fish support the largest fisheries in the world but also play key roles in marine food webs by transferring energy from plankton to upper trophic-level predators, such as large fish, seabirds, and marine mammals. Fishing can, thereby, have far reaching consequences on marine food webs unless safeguards are in place to avoid depleting forage fish to dangerously low levels, where dependent predators are most vulnerable. However, disentangling the contributions of fishing vs. natural processes on population dynamics has been difficult because of the sensitivity of these stocks to environmental conditions. Here, we overcome this difficulty by collating population time series for forage fish populations that account for nearly two-thirds of global catch of forage fish to identify the fingerprint of fisheries on their population dynamics. Forage fish population collapses shared a set of common and unique characteristics: high fishing pressure for several years before collapse, a sharp drop in natural population productivity, and a lagged response to reduce fishing pressure. Lagged response to natural productivity declines can sharply amplify the magnitude of naturally occurring population fluctuations. Finally, we show that the magnitude and frequency of collapses are greater than expected from natural productivity characteristics and therefore, likely attributed to fishing. The durations of collapses, however, were not different from those expected based on natural productivity shifts. A risk-based management scheme that reduces fishing when populations become scarce would protect forage fish and their predators from collapse with little effect on long-term average catches.

Marine Reserves: from Beverton and Holt to the Present

Abstract: The idea of using marine reserves, where all fishing is banned is not new to fisheries management. It was first formally considered by Beverton and Holt but rejected in favour of approaches such as fleet and gear control. Since that analysis, many fisheries have collapsed worldwide, illustrating the vulnerability of fishery resources and the ineffectiveness of these approaches. Empirical data and modelling suggest that marine reserves would generally increase yields, especially at the high fishing mortality that occurs in most fisheries. However, the most interesting feature of reserves is their ability to provide resilience to overexploitation, thereby reducing the risk of stock collapse. Benefits from reserves come from the increase in biomass and individual size within them, resulting in adult migration and/or larval dispersal that would replenish fishing grounds. The use of marine reserves in managing fisheries necessitates a thorough understanding of critical habitat requirements, fish movement, fish behaviour, the relations between subpopulations and the critical density effect for larval dispersal. When properly designed, and coupled with other management practices, reserves may provide a better insurance against uncertainties in stock assessment, fishing control and management by protecting a part of the population from exploitation. This strategy can be used for both sedentary and migratory species.