Loading...
2 results
Search Results
Now showing 1 - 2 of 2
- Climate change vulnerability assessment of the main marine commercial fish and invertebrates of PortugalPublication . Bueno-Pardo, Juan; Nobre, Daniela; Monteiro, J. N.; Sousa, Pedro M.; Costa, Eudriano; Baptista, Vânia; Ovelheiro, Andreia; Vieira, Vasco; Chicharo, Luis; Gaspar, Miguel; Erzini, Karim; Kay, Susana; Queiroga, Henrique; Teodosio, Maria; Leitão, FranciscoThis is the first attempt to apply an expert-based ecological vulnerability assessment of the effects of climate change on the main marine resources of Portugal. The vulnerability, exposure, sensitivity, adaptive capacity, and expected directional effects of 74 species of fish and invertebrates of commercial interest is estimated based on criteria related to their life-history and level of conservation or exploitation. This analysis is performed separately for three regions of Portugal and two scenarios of climate change (RCP 4.5 and RCP 8.5). To do that, the fourth assessment report IPCC framework for vulnerability assessments was coupled to the outputs of a physical-biogeochemical model allowing to weight the exposure of the species by the expected variability of the environmental variables in the future. The highest vulnerabilities were found for some migratory and elasmobranch species, although overall vulnerability scores were low probably due to the high adaptive capacity of species from temperate ecosystems. Among regions, the highest average vulnerability was estimated for the species in the Central region while higher vulnerabilities were identified under climate change scenario RCP 8.5 in the three regions, due to higher expected climatic variability. This work establishes the basis for the assessment of the vulnerability of the human activities relying on marine resources in the context of climate change.
- Effect of bait type on the octopus fishery in Algarve, Southern PortugalPublication . Leitão, Francisco; Bueno-Pardo, Juan; Ovelheiro, Andreia; Monteiro, J. N.; Nobre, Daniela; Teodosio, MAIn Algarve, southern Portugal, a fishery regulation was established forbidding the use of live crab as bait for the octopus fishing. Such a regulation was not established under a scientific fundament. The objective of this work was to identify if using live crab as bait affects the octopus fishery. Time series (1989–2015) were analysed in order to calculate octopus catch rates (as Landing Per Unit Effort or LPUE) and revenues (as revenue per unit effort or RPUE) before and after the crab bait ban in 2009 and also by bait type (crab and fish) before ban. Overall, total annual fishing effort decreased as result of the decreasing number of boats and fishing days in the local and coastal fleets. After the ban both the LPUE and RPUE increased, with total landings showing no change through time but mean landings per boat increased. Between 1989 and 2009, the mean monthly fishing effort in the coastal fleet was higher when crab bait was used (3.88%) in comparison to using fish bait (0.3%). This result is superimposed by the large inter annual variability between the local and coastal fleets (39.11%). In consequence, no substantial evidence was found indicating that crab bait produced high octopus catch rates, while fishing effort indicated that such high octopus catch rate and revenue increase was due to the decline of number of boats and fishing effort, that was decreasing significantly regardless of the bait type and fleet before to crab ban, and not to the bait type used during this period.