Loading...
8 results
Search Results
Now showing 1 - 8 of 8
- Adding Value to Bycatch Fish Species Captured in the Portuguese Coast—Development of New Food ProductsPublication . Silva, Frederica; Duarte, Ana M.; Mendes, Susana; Borges, Patrícia; Magalhães, Elisabete; Pinto, Filipa R.; Barroso, Sónia; Neves, Ana; Sequeira, Vera; Vieira, Ana Rita; Magalhães, Maria Filomena; Sampaio e rebelo, Rui; Assis, Carlos; Gordo, Leonel Serrano; Gil, Maria ManuelWe live in a world of limited biological resources and ecosystems, which are essential to feed people. Consequently, diversifying target species and considering full exploitation are essential for fishery sustainability. The present study focuses on the valorization of three low commercial value fish species (blue jack mackerel, Trachurus picturatus; black seabream, Spondyliosoma cantharus; and piper gurnard, Trigla lyra) and of two unexploited species (comber, Serranus cabrilla and boarfish, Capros aper) through the development of marine-based food products with added value. A preliminary inquiry with 155 consumers from Região de Lisboa e Vale do Tejo (Center of Portugal) was conducted to assess fish consumption, the applicability of fish product innovation, and the importance of valorizing discarded fish. Five products (black seabream ceviche, smoked blue jack mackerel pâté, dehydrated piper gurnard, fried boarfish, and comber pastries) were developed and investigated for their sensory characteristics and consumer liking by hedonic tests to 90 consumers. The most important descriptors were identified for each product (texture, flavor, color, and appearance). Comber pastries had the highest purchase intention (88%), followed by black seabream ceviche (85%) and blue jack mackerel pâté (76%). Sensory evaluations showed a clear tendency of consumers to accept reformulated products, with the introduction of the low-value and unexploited species under study.
- Enhancing knowledge on low‐value fishing species: the distinct reproductive strategy of two gurnard speciesPublication . Neves, Ana; Sousa, Inês; Sequeira, Vera; Vieira, Ana Rita; Silva, Elisabete; Silva, Frederica; Duarte, Ana Marta; Mendes, Susana; Ganhão, Rui; Assis, Carlos; Sampaio e rebelo, Rui; Magalhães, Maria Filomena; Gil, Maria Manuel; Gordo, Leonel SerranoThe depletion and overexploitation of several fish stock demands for a valorisation of non-target and discarded species. Nonetheless, such species are often poorly studied, and information on their biological parameters must be gathered for effective population management. For 1 year, the reproductive strategy of the piper gurnard Trigla lyra and the red gurnard Chelidonichthys cuculus was studied by monthly samples obtained from commercial boats operating on western Portuguese coast. Both species showed a biased sex ratio towards females, especially for larger length classes. Length at first maturity could be estimated only for red gurnard (22.1 and 19.9 cm for females and males, respectively) because all piper gurnard individuals caught were mature. Piper gurnard showed determinate fecundity and a short spawning season, from November to February with a peak in January, whereas red gurnard showed indeterminate fecundity and a wide spawning season, from late December to May. The relative annual fecundity estimated for red gurnard (1893 ± 728 oocytes × g−1 eviscerated weight [EW]) was higher than the one estimated for piper gurnard (1018 ± 250 oocytes×g−1 EW). Although important information for understanding the species dynamics is presented in this study, additional information on other life-history parameters and of species landings is required.
- Seasonal study of the nutritional composition of unexploited and low commercial value fish species from the Portuguese coastPublication . Duarte, Ana M.; Silva, Frederica; Mendes, Susana; Pinto, Filipa R.; Barroso, Sónia; Silva, Elisabete; Neves, Ana; Sequeira, Vera; Magalhães, Maria; Sampaio e rebelo, Rui; Assis, Carlos; Vieira, Ana Rita; Gordo, Leonel Serrano; Gil, Maria ManuelTarget species diversification is essential for fisheries sustainability and fish market revitalization. Fish discards are a widely recognized problem resulting from fisheries worldwide, and are of major concern for all sector players, from administrations, to fishermen, and scientists. However, non-target species are seldom studied, and information on nutritional profiles and seasonal changes in nutritional properties is generally lacking. This study assessed the seasonal nutritional composition of two unexploited (Serranus cabrilla, Capros aper) and three low commercial value fish species (Trachurus picturatus, Spondyliosoma cantharus, and Trigla lyra), captured on the Portuguese coast over 1 year. Significant seasonal variations were observed in the nutritional composition of all the species studied. Moisture and ash contents varied from 70% to 81% and from 5% to 13%, respectively. The maximum fat contents were 5% for C. aper and 4% for T. picturatus, allowing to classify all studied fishes as lean. The highest protein contents were recorded for C. aper (25%) and S. cantharus (20%). The unexploited and low commercial value fish species studied were shown to be good fat and protein sources, comparable to commonly consumed species, such as cod and salmon, having a great potential to become commonly consumed fish in Portugal.
- Seasonal study of the nutritional composition of unexploited and low commercial value fish species from the Portuguese coastPublication . Duarte, Ana M.; Silva, Frederica; Mendes, Susana; Pinto, Filipa R.; Barroso, Sónia; Silva, Elisabete; Neves, Ana; Sequeira, Vera; Magalhães, Maria; Sampaio e rebelo, Rui; Assis, Carlos; Vieira, Ana Rita; Gordo, Leonel Serrano; Gil, Maria ManuelTarget species diversification is essential for fisheries sustainability and fish market revitalization. Fish discards are a widely recognized problem resulting from fisheries worldwide, and are of major concern for all sector players, from administrations, to fishermen, and scientists. However, non-target species are seldom studied, and information on nutritional profiles and seasonal changes in nutritional properties is generally lacking. This study assessed the seasonal nutritional composition of two unexploited (Serranus cabrilla, Capros aper) and three low commercial value fish species (Trachurus picturatus, Spondyliosoma cantharus, and Trigla lyra), captured on the Portuguese coast over 1 year. Significant seasonal variations were observed in the nutritional composition of all the species studied. Moisture and ash contents varied from 70% to 81% and from 5% to 13%, respectively. The maximum fat contents were 5% for C. aper and 4% for T. picturatus, allowing to classify all studied fishes as lean. The highest protein contents were recorded for C. aper (25%) and S. cantharus (20%). The unexploited and low commercial value fish species studied were shown to be good fat and protein sources, comparable to commonly consumed species, such as cod and salmon, having a great potential to become commonly consumed fish in Portugal.
- Modelling Fish Growth with Imperfect Data: The Case of Trachurus picturatusPublication . Neves, Ana; Vieira, Ana Rita; Sequeira, Vera; Silva, Elisabete; Silva, Frederica; Duarte, Ana Marta; Mendes, Susana; Ganhão, Rui; Assis, Carlos; Sampaio e rebelo, Rui; Magalhães, Maria Filomena; Gil, Maria Manuel; Gordo, Leonel SerranoGrowth modelling is essential to inform fisheries management but is often hampered by sampling biases and imperfect data. Additional methods such as interpolating data through back-calculation may be used to account for sampling bias but are often complex and time-consuming. Here, we present an approach to improve plausibility in growth estimates when small individuals are under-sampled, based on Bayesian fitting growth models using Markov Chain Monte Carlo (MCMC) with informative priors on growth parameters. Focusing on the blue jack mackerel, Trachurus picturatus, which is an important commercial fish in the southern northeast Atlantic, this Bayesian approach was evaluated in relation to standard growth model fitting methods, using both direct readings and back-calculation data. Matched growth parameter estimates were obtained with the von Bertalanffy growth function applied to back-calculated length at age and the Bayesian fitting, using MCMC to direct age readings, with both outperforming all other methods assessed. These results indicate that Bayesian inference may be a powerful addition in growth modelling using imperfect data and should be considered further in age and growth studies, provided relevant biological information can be gathered and included in the analyses.
- Modelling Fish Growth with Imperfect Data: The Case of Trachurus picturatusPublication . Neves, Ana; Vieira, Ana Rita; Sequeira, Vera; Silva, Elisabete; Silva, Frederica; Duarte, Ana Marta; Mendes, Susana; Ganhão, Rui; Assis, Carlos; Sampaio e rebelo, Rui; Magalhães, Maria Filomena; Gil, Maria Manuel; Gordo, Leonel SerranoGrowth modelling is essential to inform fisheries management but is often hampered by sampling biases and imperfect data. Additional methods such as interpolating data through back-calculation may be used to account for sampling bias but are often complex and time-consuming. Here, we present an approach to improve plausibility in growth estimates when small individuals are under-sampled, based on Bayesian fitting growth models using Markov Chain Monte Carlo (MCMC) with informative priors on growth parameters. Focusing on the blue jack mackerel, Trachurus picturatus, which is an important commercial fish in the southern northeast Atlantic, this Bayesian approach was evaluated in relation to standard growth model fitting methods, using both direct readings and back-calculation data. Matched growth parameter estimates were obtained with the von Bertalanffy growth function applied to back-calculated length at age and the Bayesian fitting, using MCMC to direct age readings, with both outperforming all other methods assessed. These results indicate that Bayesian inference may be a powerful addition in growth modelling using imperfect data and should be considered further in age and growth studies, provided relevant biological information can be gathered and included in the analyses.
- Negative impact on the reproductive potential of blue jack mackerel Trachurus picturatus by Kudoa infection of the ovaryPublication . Neves, Ana; Gordo, I.; Sequeira, Vera; Vieira, Ana Rita; Silva, E.; Silva, F.; Duarte, A.M.; Mendes, S.; Ganhão, R.; Peleteiro, M.C.; Assis, Carlos; Sampaio e Rebelo, Rui; Magalhães, Maria; Gil, M.M.; Gordo, Leonel S.Reproduction of Trachurus picturatus off the western Portuguese coast was studied over 1 yr. During histological analyses, the presence of Kudoa sp. was detected in advanced vitellogenic oocytes. Kudoa infections are known to cause economic loss through the induction of postmortem liquefaction of fish muscles, but ovarian infection as reported in this study will seriously affect the reproductive potential of the species and thus impact fisheries productivity. Only females showed gonad infection which led to total degradation of advanced vitellogenic oocytes. No macroscopic, somatic or condition indices revealed differences between infected and uninfected females, rendering this infection event a concealed suppression of reproduction.
- Increasing biological knowledge for better management of by-catch species: age, growth, and mortality of piper and red gurnards (Teleostei: Triglidae)Publication . Sequeira, Vera; Sousa, Inês; Neves, Ana; Rita Vieira, Ana; Silva, Elisabete; Silva, Frederica; Duarte, Ana Marta; Mendes, Susana; Ganhão, Rui; Assis, Carlos Alberto; Sampaio e rebelo, Rui; Magalhães, Maria Filomena; Gil, Maria Manuel; Serrano Gordo, LeonelGurnards are a valuable by-catch of mixed demersal fisheries and are commercially important in European waters, but they are often discarded, reported under “mixed gurnards” and with incomplete biological information by spe-cies. In the present work, a total of 558 piper gurnard specimens of between 10.9 and 44.4 cm (1 to 11 years) and 425 red gurnard specimens of between 10.2 and 42.1 cm (0 to 9 years) from the northeast Atlantic (Portuguese) coast were used to study age and growth. The von Bertalanffy growth parameters for piper gurnard were estimated through the combination of whole-otolith readings and back-calculation (L∞=44.7 cm, k=0.16 yr–1 and t0=–2.781 yr). For red gurnard the same growth parameters were estimated using whole-otolith readings (L∞=40.2 cm, k=0.28 yr–1 and t0=–1.074 yr). The results indicate that the red gurnard reaches a smaller length, although it grows faster than the piper gurnard. Natural, instantaneous and fishing mortalities were estimated as well as the exploitation rate for both species. For the Portuguese coast, the red gur-nard showed a higher fishing mortality and exploitation rate than the piper gurnard, raising concerns about its sustainable management.