36 research outputs found
Climate impact on Italian fisheries (Mediterranean Sea)
Global warming is increasingly affecting marine ecosystems and ecological services they provide. One of the major consequences is a shift in species geographical distribution, which may affect resources availability to fisheries. We computed the mean temperature of the catch (MTC) for Italian catches from 1972 to 2012 to test if an increase of warmer-water species against colder-water ones was observed. We further analysed the relationship among MTC, landings, fishing effort and climatic factors through a Linear Mixed Models approach. Global MTC increased at a rate of 0.12 _C per decade. Though, by considering the influence of sea surface temperature (SST), a strongest increase (0.31 _C) was estimated in southernmost areas, while in the northernmost basin (Northern Adriatic Sea) a decrease of 0.14 _C was observed. SST resulted the most relevant driver, and the relationship between MTC and SST showed a high spatial variability both in terms of strength and sign, being positively stronger in southernmost areas while negative in the northernmost basin. The result is probably underestimated since several psychrophilous and thermophilous species were not included in the analysis. However, it seems that a change towards warmer-water species has already occurred in Italian marine ecosystems. Conversely, total landings temporal dynamics seem mostly driven by changes in fishing effort rather than by MTC and climatic factors. Consequently, fishery management strategies need to focalize primarily on fishing effort reduction, in order to reduce the pressure on the stocks while increasing their resilience to other stressors, among which global warmingGlobal warming is increasingly affecting marine ecosystems and ecological services they provide. One of the major consequences is a shift in species geographical distribution, which may affect resources availability to fisheries. We computed the mean temperature of the catch (MTC) for Italian catches from 1972 to 2012 to test if an increase of warmer-water species against colder-water ones was observed. We further analysed the relationship among MTC, landings, fishing effort and climatic factors through a Linear Mixed Models approach. Global MTC increased at a rate of 0.12 A degrees C per decade. Though, by considering the influence of sea surface temperature (SST), a strongest increase (0.31 A degrees C) was estimated in southernmost areas, while in the northernmost basin (Northern Adriatic Sea) a decrease of 0.14 A degrees C was observed. SST resulted the most relevant driver, and the relationship between MTC and SST showed a high spatial variability both in terms of strength and sign, being positively stronger in southernmost areas while negative in the northernmost basin. The result is probably underestimated since several psychrophilous and thermophilous species were not included in the analysis. However, it seems that a change towards warmer-water species has already occurred in Italian marine ecosystems. Conversely, total landings temporal dynamics seem mostly driven by changes in fishing effort rather than by MTC and climatic factors. Consequently, fishery management strategies need to focalize primarily on fishing effort reduction, in order to reduce the pressure on the stocks while increasing their resilience to other stressors, among which global warming
Recommended from our members
Vessel monitoring systems (VMS) reveal an increase in fishing efficiency following regulatory changes in a demersal longline fishery
A global expansion of satellite-based monitoring is making fisher behavioral responses to management actions increasingly observable. However, such data have been underutilized in evaluating the impacts of fishing on target and non-target fish stocks or the ramifications of management strategies on fishers. We demonstrate how vessel monitoring system (VMS) data can provide a suite of metrics (such as effort) for improving inputs to stock assessments, dynamic delineation of fishing grounds, and evaluation of regulatory or other (e.g., climatic) impacts on fisher performance. Using >1 million VMS records from the Gulf of Mexico grouper-tilefish demersal longline fishery, we first develop a generalized additive modeling approach that predicts fishing duration with ∼85% accuracy. We combine model predictions with logbook data to compare the fishery before and after implementation of a suite of regulatory changes (e.g., a shift to catch share management). We find a large-scale reduction in fleet size, accompanied by reduced fishing effort (duration * number of hooks), shorter trips, lower operational expenses, higher catch rates, and more earnings for those vessels that remained in the fishery. We discuss how the combination of VMS and associated metrics can be expanded for use in management strategy evaluation, parameterizing economic models of fisher behavior, improving fishery-dependent stock assessment indices, and deriving socioeconomic indicators in fisheries worldwide
Recommended from our members
Vessel monitoring systems (VMS) reveal an increase in fishing efficiency following regulatory changes in a demersal longline fishery
A global expansion of satellite-based monitoring is making fisher behavioral responses to management actions increasingly observable. However, such data have been underutilized in evaluating the impacts of fishing on target and non-target fish stocks or the ramifications of management strategies on fishers. We demonstrate how vessel monitoring system (VMS) data can provide a suite of metrics (such as effort) for improving inputs to stock assessments, dynamic delineation of fishing grounds, and evaluation of regulatory or other (e.g., climatic) impacts on fisher performance. Using >1 million VMS records from the Gulf of Mexico grouper-tilefish demersal longline fishery, we first develop a generalized additive modeling approach that predicts fishing duration with ∼85% accuracy. We combine model predictions with logbook data to compare the fishery before and after implementation of a suite of regulatory changes (e.g., a shift to catch share management). We find a large-scale reduction in fleet size, accompanied by reduced fishing effort (duration * number of hooks), shorter trips, lower operational expenses, higher catch rates, and more earnings for those vessels that remained in the fishery. We discuss how the combination of VMS and associated metrics can be expanded for use in management strategy evaluation, parameterizing economic models of fisher behavior, improving fishery-dependent stock assessment indices, and deriving socioeconomic indicators in fisheries worldwide
Heterogeneous Response to Marine Reserve Formation: A Sorting Model approach
Marine reserves, Locational sorting, Heterogeneous behavior, Survey, Q22, C35,