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.

Food-web changes in the Adriatic Sea over the last three decades

Abstract: We used a process-oriented model (Ecosim) to characterize changes in marine resources in the north-central (NC) Adriatic Sea (Mediterranean) from 1975 to 2002, and to explore the extent to which these changes were driven by trophic interactions, environment and fishing. Fishing efforts and fishing mortalities were used to drive the ecosystem model, and available biomass and catch data were compared to the model predictions. We calibrated and assessed the fit of the model using the sum of the squared deviations of the observed and predicted biomass values. Trophodynamic indica- tors were then calculated and used to analyse changes to the ecosystem. Trophic interactions, fishing, and environmental conditions were important driving factors of the ecosystem. Predictions from the model adequately matched observed biomass and catch data for each year. Observed trends and pre- dicted data for biomasses decreased with time for several species, including Norway lobster, hake, red mullets, flatfish, and anchovy. The environmental functions resulting from the fitting procedure predicted that primary production and nutrients increased beyond the baseline from 1975 level, and then showed a decrease. They were negatively correlated with mean sea surface temperature and positively correlated with the Mediterranean Oscillation Index. Our results suggested that the NC Adriatic ecosystem became more degraded over time due to expanding fishing effort, bottom-up effects, and climatic anomalies. Possible mechanisms involved are discussed. Comparing our findings with descriptions of the south Catalan Sea ecosystem showed certain similarities between these 2 Mediterranean ecosystems and revealed unique features of the Adriatic Sea.

Community, State, and Market on the North Atlantic Rim: Challenges to Modernity in the Fisheries

Abstract: This is a study of Northern Norway and Atlantic Canada, two regions experiencing a severe crisis due to overexploitation of fisheries resources. The work of a group of researchers from Canada, Norway, and the United States, it examines the implications of common market integration, privatized resource management, and small business development policies for fishery-dependent communities in terms of long-term sustainability and participatory democracy. The book is broken into three sections: an examination of the economic and institutional history of the fisheries in Norway and Atlantic Canada, a study of the regulatory regimes used in the fisheries of these two regions, and an analysis of reactions in three communities, two in Canada and one in Norway, to the decline and collapse of fish stocks. Comparative, multidisciplinary, and multinational in approach, it is a major contribution to the literature on fishing regulations, the role of the state, and resource development in the North Atlantic.

Silent fish surveys: bubble-free diving highlights inaccuracies associated with SCUBA-based surveys in heavily fished areas

Abstract: Summary 1. Underwater visual census (UVC) using SCUBA is a commonly used method for assessing reef fish communities. Evidence suggests, however, that fish avoid divers due to the sound of bubbles produced by open-circuit SCUBA, and avoidance behaviour is more pronounced as fishing pressure increases. Despite the potential for producing biased counts and conclusions, these behavioural effects have rarely been quantified, especially when assessing the effectiveness of marine protected areas (MPAs). 2. To test the magnitude of avoidance behaviour, we surveyed fish populations inside and outside two MPAs in Guam, using two diving systems: standard open-circuit (OC) SCUBA and a closed-circuit rebreather (CCR) that produces no bubbles. Data were collected using a diver-operated stereo-video system (stereo-DOV), which provided counts of relative abundance, measures of fish length and the minimum approach distance of the diver to a fish. 3. Inside MPAs, fish surveys conducted with CCR recorded similar community metrics to fish surveys conducted with conventional OC SCUBA. In contrast, outside the MPAs, the bubble-free diving system recorded 48% more species and up to 260% greater fish abundance. These differences reflected the ability of a diver wearing the silent CCR unit to sample the larger, most heavily targeted species that are shy of divers in fished areas. This difference was also large enough to change some results from ‘reject’ to ‘accept’ the null hypothesis of ‘no significant differences exist between fished and protected areas’. 4. The use of CCR for fish surveys clearly minimizes behavioural biases associated with fish avoiding open-circuit SCUBA divers. We recommend the use of this bubble-free diving system for surveys assessing reef fish populations, especially in areas where fish are heavily targeted by spearfishing. If fish behaviour is not accounted for, surveys using SCUBA could result in erroneous conclusions when comparing fished and protected areas. While the behaviour of fish towards divers is rarely mentioned in conclusions from studies using UVC, it is an important source of bias that should be acknowledged and minimized where possible.

Small-scale Fisheries, Population Dynamics, and Resource Use in Africa: The Case of Moree, Ghana

Abstract: We consider population dynamics and sustainable use and development of fishery resources in Moree, a small-scale fishing and coastal community of 20 000 people in the Central Region of Ghana near Cape Coast. Moree suggests that relationships between population dynamics and fishery resources are more complex than the concept of Malthusian overfishing implies. Reasons include changing biophysical characteristics of the upwelling system along the coast of West Africa; qualitative as well as quantitative changes in fishing activity throughout the year; the market nature of fishing activity and nonlocal demands for fish; regular fishery migration; and institutions regulating fishery resource access at home and at migration destinations. Population and resource relationships in Moree may be the effects of fishery resource and economic changes on migration rather than population pressure on fishery resources. Fisheries management policies must take into account processes that lie beyond the influence of...