scholarly journals Catch, bycatch and discards of the Galapagos Marine Reserve small-scale handline fishery

PeerJ ◽  
2015 ◽  
Vol 3 ◽  
pp. e995 ◽  
Author(s):  
Johanna S. Zimmerhackel ◽  
Anna C. Schuhbauer ◽  
Paolo Usseglio ◽  
Lena C. Heel ◽  
Pelayo Salinas-de-León
Keyword(s):  
Marine Reserve ◽  
Small Scale ◽  
Galapagos Marine Reserve

scholarly journals Catch, bycatch and discards of the Galapagos Marine Reserve small-scale handline fishery

2015 ◽  
Author(s):  
Johanna S Zimmerhackel ◽  
Anna C Schuhbauer ◽  
Paolo Usseglio ◽  
Lena C Heel ◽  
Pelayo Salinas-de-León
Keyword(s):  
Marine Reserve ◽  
Marine Conservation ◽  
Economic Consequences ◽  
Small Scale ◽  
Local Market ◽  
Target Species ◽  
Fisheries Bycatch ◽  
Spatio Temporal ◽  
Catch Composition ◽  
Galapagos Marine Reserve

Fisheries bycatch is one of the most significant marine conservation issues as valuable fish are wasted and protected species harmed with potential negative ecological and socio-economic consequences. Even though there are indications that the small-scale handline fishery of the Galapagos Marine Reserve has a low selectivity, information on its bycatch never has been published. We therefore assessed the bycatch of the Galapagos handline fishery by estimating the bycatch ratio, determining species compositions of landings and bycatch, and identifying fishers’ reasons for discarding certain individuals using onboard monitoring and interview data. Moreover, we used interview surveys to reveal historical trends in the bycatch ratio. The estimated bycatch ratio of 0.40 confirmed a low selectivity of this fishery. Characterisation of the catch resulted in a total of 19 target species which were dominated by groupers, and 53 non-target species, with grunts and groupers being most prominent. Most individuals were not landed for economic motivations, either because species (77.4%) or sizes (17.7%) are not marketable and to a lesser extent for regulatory reasons (5.9%). However, sharks were after grunts with 69% the second most often mentioned bycatch taxa during interview surveys. We found that small sized individuals of some of the most exploited species suffer high bycatch mortality because they are used as bait. Moreover, over half of interviewees perceived a historical decrease in bycatch ratios that was explained by a diversification of the catch composition due to the reduction in abundance of the traditionally most important target species. As some target species show signs of overfishing and to date there are no specific regulations for the finfish fishery in place, we recommend the investigation of different gear settings such as the use of different hooks and bait species. Furthermore, we suggest the integration of faster growing species to the local market as well as spatio-temporal closures, and minimum and maximum catch sizes for overexploited species in order to improve the selectivity and sustainability of the Galapagos handline fishery.

scholarly journals Catch, bycatch and discards of the Galapagos Marine Reserve small-scale handline fishery

2015 ◽  
Author(s):  
Johanna S Zimmerhackel ◽  
Anna C Schuhbauer ◽  
Paolo Usseglio ◽  
Lena C Heel ◽  
Pelayo Salinas-de-León
Keyword(s):  
Marine Reserve ◽  
Marine Conservation ◽  
Economic Consequences ◽  
Small Scale ◽  
Local Market ◽  
Target Species ◽  
Fisheries Bycatch ◽  
Spatio Temporal ◽  
Catch Composition ◽  
Galapagos Marine Reserve

Fisheries bycatch is one of the most significant marine conservation issues as valuable fish are wasted and protected species harmed with potential negative ecological and socio-economic consequences. Even though there are indications that the small-scale handline fishery of the Galapagos Marine Reserve has a low selectivity, information on its bycatch never has been published. We therefore assessed the bycatch of the Galapagos handline fishery by estimating the bycatch ratio, determining species compositions of landings and bycatch, and identifying fishers’ reasons for discarding certain individuals using onboard monitoring and interview data. Moreover, we used interview surveys to reveal historical trends in the bycatch ratio. The estimated bycatch ratio of 0.40 confirmed a low selectivity of this fishery. Characterisation of the catch resulted in a total of 19 target species which were dominated by groupers, and 53 non-target species, with grunts and groupers being most prominent. Most individuals were not landed for economic motivations, either because species (77.4%) or sizes (17.7%) are not marketable and to a lesser extent for regulatory reasons (5.9%). However, sharks were after grunts with 69% the second most often mentioned bycatch taxa during interview surveys. We found that small sized individuals of some of the most exploited species suffer high bycatch mortality because they are used as bait. Moreover, over half of interviewees perceived a historical decrease in bycatch ratios that was explained by a diversification of the catch composition due to the reduction in abundance of the traditionally most important target species. As some target species show signs of overfishing and to date there are no specific regulations for the finfish fishery in place, we recommend the investigation of different gear settings such as the use of different hooks and bait species. Furthermore, we suggest the integration of faster growing species to the local market as well as spatio-temporal closures, and minimum and maximum catch sizes for overexploited species in order to improve the selectivity and sustainability of the Galapagos handline fishery.

scholarly journals Factors affecting relative abundance of low-mobility fishing resources: spiny lobster in the Galapagos Marine Reserve

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7278 ◽  
Author(s):  
Juan Carlos Murillo-Posada ◽  
Silvia Salas ◽  
Iván Velázquez-Abunader
Keyword(s):  
Monitoring System ◽  
Relative Abundance ◽  
Spatial Scales ◽  
Marine Reserve ◽  
Spiny Lobster ◽  
Fishing Effort ◽  
Additive Models ◽  
Catch Per Unit Effort ◽  
Monthly Basis ◽  
Galapagos Marine Reserve

Management of low-mobility or benthic fisheries is a difficult task because variation in the spatial distribution and population dynamics of the resources make the monitoring and assessment of these fisheries challenging. We assumed that environmental, spatial, and temporal factors can contribute to the variability of the relative abundance of such species; we used Generalized Additive Models for Location Scale and Shape (GAMLSS) to test this hypothesis using as a case study the lobster fishery (targeting two species) in the Galapagos Marine Reserve, Ecuador. We gathered data on each of the two species of lobster on a monthly basis over seven years, including: (a) onboard observers’ records of catch data, fishing effort, and ground location by trip, and (b) data from interviews undertaken with fishers at their arrival to port, recording the same type of information as obtained from onboard observers. We use this information to analyze the effect of the measured variables and to standardize the Catch per Unit Effort (CPUE) in each case, using the GAMLSS. For both species, the temperature, region, fishing schedule, month, distance, and the monitoring system were significant variables of the selected models associated with the variability of the catch rate. ForPanulirus penicillatus, CPUE was higher at night than during the day, and forPanulirus gracilisit was higher during the day. Increased temperature resulted in a decrease of CPUE values. It was evident that temporal, spatial scales and monitoring system can influence the variability of this indicator. We contend that the identification of drivers of change of relative abundance in low-mobility species can help to support the development of monitoring and assessment programs for this type of fisheries.

Are boat strikes a threat to sea turtles in the Galapagos Marine Reserve?

2013 ◽  
Vol 80 ◽  
pp. 29-35 ◽  
Author(s):  
Judith Denkinger ◽  
Macarena Parra ◽  
Juan Pablo Muñoz ◽  
Constanza Carrasco ◽  
Juan Carlos Murillo ◽  
...  
Keyword(s):  
Sea Turtles ◽  
Marine Reserve ◽  
Galapagos Marine Reserve
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