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.

Long-term and spillover effects of a marine protected area on an exploited fish community

Abstract: We assessed the development of the exploited fish community inside and around the Columbretes Islands Marine Reserve (CIMR), a marine protected area (MPA), 8 to 16 yr after fishing ceased in the reserve. Sampling was by annual lobster trammel net fishing, an experimental tech- nique used inside the CIMR, and on-board commercial operations in adjacent fishing grounds. We examined trends in combined fish abundance and biomass (catch per unit effort), species richness and diversity, size structure, trophic level and species composition of the community. Our results showed the CIMR fish community continued to change throughout the study period as (1) abundance and biomass increased, (2) mean body size and trophic level increased and (3) species composition changed according to a linear model. Relative to nearby fished areas the CIMR fish community had (1) higher abundance and biomass, (2) lower species diversity and higher taxonomic distinctness, (3) larger relative body size and (4) no difference in mean trophic level. We found clear evidence of spillover of fish from the CIMR to the adjacent fishery as commercial fish yields at the MPA border (<0.5 km from the boundary) increased continuously during the study period, despite being locally depleted due to fishing effort concentration (fishing the line). Furthermore, fish size and diversity at the border were intermediate between the CIMR and other fished zones, suggesting that this is a transitional zone influenced by this MPA. Our results show that changes in community abundance, biomass, size structure and species composition provide a clear and interpretable view of MPA recov- ery. Diversity indices are also useful; however, their interpretation is more difficult. We conclude that the creation of the CIMR has had a positive effect on the exploitable fish community and that there is evidence of exportation of biomass to the surrounding fishery. We highlight the advantage of using multiple community metrics to study changes in fish communities, yet recommend the need for caution when interpreting them.

A Global Estimate of the Number of Coral Reef Fishers.

Abstract: Overfishing threatens coral reefs worldwide, yet there is no reliable estimate on the number of reef fishers globally. We address this data gap by quantifying the number of reef fishers on a global scale, using two approaches - the first estimates reef fishers as a proportion of the total number of marine fishers in a country, based on the ratio of reef-related to total marine fish landed values. The second estimates reef fishers as a function of coral reef area, rural coastal population, and fishing pressure. In total, we find that there are 6 million reef fishers in 99 reef countries and territories worldwide, of which at least 25% are reef gleaners. Our estimates are an improvement over most existing fisher population statistics, which tend to omit accounting for gleaners and reef fishers. Our results suggest that slightly over a quarter of the world’s small-scale fishers fish on coral reefs, and half of all coral reef fishers are in Southeast Asia. Coral reefs evidently support the socio-economic well-being of numerous coastal communities. By quantifying the number of people who are employed as reef fishers, we provide decision-makers with an important input into planning for sustainable coral reef fisheries at the appropriate scale.

Size-spectra as indicators of the effects of fishing on coral reef fish assemblages

Abstract: The data requirements and resources needed to develop multispecies indicators of fishing impacts are often lacking and this is particularly true for coral reef fisheries. Size-spectra, relationships between abundance and body-size class, regardless of taxonomy, can be calculated from simple sizeabundance data. Both the slope and the mid-point height of the relationship can be compared at different fishing intensities. Here, we develop size-spectra for reef fish assemblages using body size- abundance data collected by underwater visual census in each of ten fishing grounds across a known gradient of fishing intensity in the Kadavu Island group, Fiji. Slopes of the size-spectra became steeper (F9,69=3.20, p<0.01) and the height declined (F9,69=15.78, p<0.001) with increasing fishing intensity. Regressions of numbers of individuals per size class across grounds were negative for all size classes, although the slope was almost zero for the smallest size class. Response to exploitation of each size class category was greatest for larger fish. Steepening of the slope with increasing fishing intensity largely resulted from reductions in the relative abundance of large fish and not from the ecological release of small fish following depletion of their predators. The slope and height of the size-spectrum appear to be good indicators of fishing effects on reef fish assemblages.

Bioeconomic Production Function in Fisheries: Theoretical and Empirical Analysis

Abstract: The traditional "fishing effort" approach to fisheries economics implies the existence of a production function with fishing effort and fish abundance as independent variables. It is shown how the ...