Browsing by Author "Vieira, Ana Rita"
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- 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, Sonia; Neves, Ana; Sequeira, Vera; Vieira, Ana Rita; Magalhães, Maria Filomena; Rebelo, Rui; Assis, Carlos; Gordo, Leonel SerranoWe 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.
- Annual variations in the mineral element content of five fish species from the Portuguese coastPublication . Pinto, Filipa R.; Duarte, Ana M.; Silva, Frederica; Barroso, Sonia; Mendes, Susana; Pinto, Edgar; Almeida, Agostinho; Sequeira, Vera; Vieira, Ana Rita; Gordo, Leonel Serrano; Gil, Maria MThe most consumed fish species in Portugal do not correspond to the most caught fish species on the Portuguese coast. From the point of view of ocean sustainability and economics, it is important to study unexploited or underexploited fish species that have the potential to be introduced into the food market. This potential can be reflected by their nutritional value, where mineral elements are often overlooked despite their importance in human health. Therefore, it is important to study the elemental concentration of those fish species, which should also include seasonal variations of essential mineral elements such as Ca, P, Mg, Na, K, Fe, Cu, Mn, Zn, and I, and non-essential elements such as As, Ni, Cd, and Pb. This work is part of a project that studied five fish species with the potential to be brought to the market: three species with low commercial value (Trachurus picturatus, Spondyliosoma cantharus and Trigla lyra) and two species with no commercial value (Serranus cabrilla and Capros aper), caught over a year in the coast of Portugal. Mineral elements were quantified by ICP-OES (ICP-MS for I). The results showed that the studied fish species present significant elemental concentrations, similar to those found in the most caught fish species in Portugal. Trachurus picturatus was found to be a source of Fe, and all species are sources of I. Overall, Spondyliosoma cantharus proved to be the most element-rich species. Sensorially, Cu was related to “metallic odour” and Fe to “metallic flavour”, and I was related to “seaweed odour” and “seawater flavour”. Additionally, toxic elements such as Cd, Pb, Ni and As were not detected. The corresponding Hazard Quotients (HQ) show the safety of the consumption of these fish species concerning the content of potentially toxic elements.
- 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; 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 x g-1 eviscerated weight [EW]) was higher than the one estimated for piper gurnard (1018 ± 250 oocytes x 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.
- 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; Vieira, Ana Rita; Silva, Elisabete; Silva, Frederica; Duarte, Ana Marta; Mendes, Susana; Ganhão, Rui; Assis, Carlos; Rebelo, Rui; Magalhães, Maria Filomena; Gil, Maria Manuel; Gordo, Leonel SerranoGurnards 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 species. 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 gurnard showed a higher fishing mortality and exploitation rate than the piper gurnard, raising concerns about its sustainable management.
- 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; 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 backcalculation 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.
- Reproduction of the Blue Jack Mackerel, Trachurus picturatus, in Western Portugal: Microscopic gonad analysis reveals indeterminate fecundity and skipped spawning patternsPublication . Neves, Ana; Sequeira, Vera; Vieira, Ana Rita; Silva, Elisabete; Silva, Frederica; Duarte, Ana Marta; Mendes, Susana; Ganhão, Rui; Assis, Carlos; Rebelo, Rui; Magalhães, Maria Filomena; Gil, Maria M; Gordo, Leonel SerranoBlue jack mackerel, Trachurus picturatus, is the fifth most landed fish species in mainland Portugal, but information on its reproductive biology is scarce. From September 2018 to August 2019, 626 specimens were collected from commercial vessels to clarify the reproductive strategy of the T. picturatus population off the west coast of Portugal. The proportion and length range of males and females were similar. Only three of the specimens collected were categorized as immature, indicating that the fish caught in the fishery are primarily mature. The spawning season lasted from late January until the end of March, with gonadosomatic indices being similar for males and females. Fecundity was indeterminate, and estimated batch fecundity ranged between 6,798 (at 25.4 cm TL) and 302,358 oocytes (at 33.8 cm TL). The low number of females showing direct evidence of imminent or recent spawning suggests a low number of spawning events. In addition, 12.7% of females were considered non-reproductive due to ovary abnormalities including parasitic infection by Kudoa species, atretic structures and skipped spawning events. This study highlights the importance of accounting for skipped spawning events and ovary abnormalities in the management of species fisheries.
- Seasonal sensory evaluation of low commercial value or unexploited fish species from the Portuguese coastPublication . Silva, Frederica; Duarte, Ana M.; Mendes, Susana; Magalhães, Elisabete; Pinto, Filipa R.; Barroso, Sonia; Neves, Ana; Sequeira, Vera; Vieira, Ana Rita; Gordo, Leonel; Gil, Maria ManuelOverfishing is increasing over time, and according to FAO (Food and Agriculture Organization), about one third of the world’s fish stocks are now overfished. Thus, diversifying the target species is essential for fisheries sustainability contributing to improve resource-effcient processes. Non-target species can be valuable resources for the development of new food products. However, those species are scarcely studied, and it is of high importance to trace their seasonal sensory profile as a first step towards their valorisation. Therefore, in this study, seasonal influence on sensory properties of five low commercial value or unexploited fish species, namely Trachurus picturatus (blue jack mackerel), Spondyliosoma cantharus (black seabream), Trigla lyra (piper gurnard), Serranus cabrilla (comber) and Capros aper (boarfish), was assessed in order to identify the most favourable season for catching each species. Fish samples were assessed by a panel of 16 semi-trained assessors for sensory attributes previously identified. The evaluation takes place every 2 months. Statistical differences were reported between attributes and seasons for all species, except for T. lyra, which did not present any di erence in its sensory attributes throughout the year.
- 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, Sonia; Silva, Elisabete; Neves, Ana; Sequeira, Vera; Magalhães, Maria Filomena; Rebelo, Rui; Assis, Carlos; Vieira, Ana Rita; Gordo, Leonel Serrano; Gil, Maria M.Target 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.