Effects of leader material on catches of shallow pelagic longline fisheries in the southwest Indian Ocean

Catches from a commercial longline fishery targeting swordfish (Xiphias gladius) on monofilament nylon leaders were compared with catches on wire leaders in the Indian Ocean. More taxa were caught on wire leaders, which also showed higher catch rates (13% and 56%, in number and weight, respectively) of blue shark (Prionace glauca). In contrast, catch rates of swordfish were not significantly affected by leader material. Nylon leaders showed lower at-haulback mortality for most bony fishes, except swordfish. Higher bite-off rates were observed on nylon monofilament, likely owing to the escape of species with sharp teeth, such as sharks. Both leader types caught most species within similar size ranges, but larger mean sizes of blue shark were recorded on wire leaders. The value per unit of effort (VPUE) of the retained catch did not differ between leader materials; however, VPUEs are highly dependent on market fluctuations. Banning wire leaders could be an effective way of reducing shark catches, particularly blue shark catches, in the southwest Indian Ocean.Programa Operacional das Pescas: LL-SHARKs - Ref 31- 03-05-FEP-44, FCT IF/00253/2014info:eu-repo/semantics/publishedVersio

Characterization and standardization of Atlantic sailfish (Istiophorus albicans) catch rates in the east Atlantic from the Portuguese pelagic longline fishery

This document analyzes the catch, effort and standardized CPUE trends for the eastern Atlantic stock of Atlantic sailfish (Istiophorus albicans) captured by the Portuguese pelagic longline fleet from 1999-2015. Nominal annual CPUE were calculated as kg/1000 hooks and were standardized with Generalized Linear Models (GLM) with Tweedie distribution and using year, quarter, area and targeting effects (ratios) as explanatory variables. Model goodness-of-fit was determined with AIC and the pseudo coefficient of determination, and model validation was analyzed with residual analysis. The final standardized CPUE series shows a general decrease in the initial years, between 1999 and 2010, followed by a general increase in the more recent years, until 2015, with some inter-annual oscillations. This paper presents the first index of abundance for Atlantic sailfish estimated from captures from the Portuguese pelagic longline fleet in the east Atlantic and can be used for future stock assessments of the speciesFCT IF/00253/2014info:eu-repo/semantics/publishedVersio

Standardized CPUE of blue shark in the Portuguese pelagic longline fleet operating in the north Atlantic

This working document analyzes the catch, effort and standardized CPUE trends for the north Atlantic blue shark captured by the Portuguese pelagic longline fleet. Nominal annual CPUE were calculated as kg/1000 hooks and were standardized with Generalized Linear Models (GLM) and Generalized Linear Mixed Models (GLMM) using year, quarter, area, gear type, targeting effects and area:quarter interactions as fixed factors, and year:area as random effects. Sensitivity analyzes were carried out for the model type (lognormal, tweedie, gamma or delta lognormal), the definition of targeting effects (based on ratios or cluster analysis), and definition of areas. Model goodness-of-fit and comparison was carried out with AIC and the pseudo coefficient of determination (R2 ), and model validation with a residual analysis. The final standardized CPUE trend shows a general increase over the studied period, between 1997 and 2014, with some inter-annual oscillations. This paper presents the first index of abundance for the blue shark estimated from captures from the Portuguese pelagic longline fleet in the North Atlantic, and can be used in future stock assessments models.FCT IF/00253/2014info:eu-repo/semantics/publishedVersio

Effects of hook and bait on targeted and bycatch fishes in an equatorial atlantic pelagic longline fishery

We examined the effects of different hook style and bait type combinations on the catches of targeted, bycatch, and discarded fishes in equatorial Atlantic waters. In total, 221 longline sets (>305,000 hooks) were deployed from Portuguese pelagic longline vessels (SELECT -PAL Project) during the February–October fishing season. Three different hook styles and two bait types were tested: the traditional J-hook was compared to two circle hooks (one non-offset and one with 10° offset), and squid bait was compared to mackerel. Catch per unit effort (CPU Es) were calculated and compared between the different hook style and bait type combinations, which indicated that the effects of hook style and bait on the CPU Es were species-specific. For example, swordfish CPU Es were higher with J-hooks baited with squid, while for targeted tunas and blue shark only the bait effect was significant, but with opposite effect (i.e., higher catches of tuna with squid bait and higher catches of blue shark with mackerel bait). For the discarded species, at-haulback mortality was also species-specific. Proportions of alive vs dead specimens at time of fishing gear retrieval did not vary significantly by hook style or bait type combinations. The total retained catch was analyzed in value per unit effort (VPU E), and indicated losses in fishery revenue when mackerel was used instead of squid, but not when circle hooks were used instead of J-hooks.info:eu-repo/semantics/publishedVersio

Observations on small tunas caught in the tuna trap fishery off southern Portugal (NE Atlantic) between 1996 and 2014

This study reports on the trends of small tuna catches from a tuna trap operating off the southern coast of Portugal between 1996 and 2014. Landing and catch at size data from one tuna trap were available for bullet tuna (Auxis rochei), Atlantic bonito (Sarda sarda) and little tunny (Euthynnus alletteratus). Trends of intra- and inter-annual catches for the three species were analyzed. Landings occurred mostly during the 2nd and 3rd quarters, with peaks in May for A. rochei and in September for S. sarda and E. alletteratus. Catch at size data shows that similar size ranges of the three species were captured.FCT IF/00253/2014info:eu-repo/semantics/publishedVersio

New observations on the bluefin tuna trap fishery off southern Portugal (NE Atlantic) between 1998-2014: trends on potential catches, catch-at-size and sex ratios

This paper updates information previously presented on the bluefin tuna catches from a tuna trap fishery operating off the southern coast of Portugal (Algarve). Trends of intra- and interannual catches were analysed and relationships between the potential catches and ICCAT management regulations for the Mediterranean Sea explored. The catch rates of bluefin tuna in the tuna trap off the Algarve remained relatively low between 1998 and 2008, but were followed by increasingly high catches thereafter, with an observed peak during the 2011 season. Significant negative correlations were observed between the catches and the number of allowable fishing months for purse-seines, longlines and bait boats in the Mediterranean Sea, meaning that the catch increased as the number of allowable fishing months for those fishing gears decreased. On the other hand, a positive relationship was observed between the catches and the minimum landing size (MLS), meaning that the catch rates in the tuna trap increased as the MLS for bluefin tuna also increased. These results seem to corroborate other fisheries indicators regarding the recovery of the Eastern Atlantic and Mediterranean Sea stock.FCT IF/00253/2014info:eu-repo/semantics/publishedVersio

Desenvolvimento de um indicador de melhoria contínua

Mestrado em Engenharia e Gestão IndustrialO presente relatório resulta do desenvolvimento de um projecto de estágio efectuado, ao longo de nove meses, na empresa Bosch Termotecnologia SA. O objectivo deste trabalho é a definição da forma de cálculo de um indicador, que permitirá avaliar a frequência com que é produzido um grupo específico de produtos da empresa. O cálculo periódico deste indicador e, consequentemente, o seu acompanhamento irão permitir uma maior transparência no processo de planeamento de produção, assim como uma maior estabilidade para a cadeia de valor da empresa, contribuindo deste modo para a optimização do processo de fabrico. ABSTRACT: The following report results from the development of a project carried out over nine months, in the company Bosch Termotecnologia SA. The aim of this study is to define the method for calculating an indicator, which will allow to evaluate the frequency with which some company’s products are produced. The periodic calculation of this indicator and consequently its monitoring will grant a greater transparency in the process of production’s planning as well as greater stability for the company's value-chain, contributing to the optimization of the manufacturing process

An overview of the hooking mortality of elasmobranchs caught in a swordfish pelagic longline fishery in the Atlantic Ocean

Hooking (or “at-haulback”) fishing mortality was analysed in elasmobranchs captured by Portuguese longliners targeting swordfish in the Atlantic Ocean. Information was collected by on-board fishery observers who monitored 834 longline fishing sets between August 2008 and December 2011, and recorded information on 36,067 elasmobranch specimens from 21 different taxa. The hooking mortality proportions were species-specific, with some species having relatively high percentages of live specimens at time of haulback (e.g., blue shark, crocodile shark, pelagic stingray, manta, devil and eagle rays), while others had higher percentages of dead specimens (e.g., smooth hammerhead, silky shark, bigeye thresher). For the most captured species, logistic GLMs were carried out to compare the mortality rates between sexes, specimen sizes and the regions of operation of the fleet. The sex-specific proportions of hooking mortality were significantly different for blue and crocodile sharks, with the males of both species having higher proportions of hooking mortality than the females. Specimen size was significant for predicting the hooking mortality for blue and shortfin mako sharks: in both cases, the larger specimens had lower odds of dying due to the fishing process. There were differences in the hooking mortality depending on the region of operation of the fleet, but those differences were also species-specific. For blue and crocodile sharks, the hooking mortality was higher in the Equatorial and southern Atlantic areas (when compared to the NE Atlantic region), while the opposite was observed for the shortfin mako, with lower mortality rates in the NE tropical area compared with the other regions. The results presented in this paper can be integrated into future ecological risk assessment analysis for pelagic elasmobranchs. Furthermore, the new information can be used to evaluate the impact of recent recommendations prohibiting the retention of some vulnerable elasmobranch species

Shark Research and Data Collection Program: progress on the satellite tagging of shortfin mako for post-release survival and habitat use studies

This paper provides an update of two projects developed within the ICCAT Shark Research and Data Collection Program (SRDCP) using satellite telemetry, specifically a study on habitat use and other on post-release survival. At the time of this paper, 10 tags (6 miniPATs and 4 sPAT) had been deployed from observers on Portuguese fishing vessels in the temperate NE Atlantic. The remaining tags are being deployed by USA in the temperate NW and Uruguay in the SW. The preliminary analysis shows that specimens tagged in the temperate NE moved to southern areas, while specimens tagged in the tropical NE close to the Cabo Verde archipelago moved easterly to the African continent. Three tags were deployed in equatorial waters and one moved to the NE while the other moved SE. In terms of post-release survivorship, 2 specimens tagged with sPATs survived and 2 died. For the 2nd year of the project we will acquire additional miniPATs to be deployed preferably in equatorial waters, in the mixing zone for the stocks.info:eu-repo/semantics/publishedVersio