Valorização de recursos pesqueiros : cavala vrp

No âmbito de uma parceria original entre uma Organização de Produtores da pesca do cerco, a Barlapesca e um Centro de Investigação dedicado às ciência do mar, o CMAR, pretendeuse com o projeto CAVALA VRP - Valorização dos Recursos Pesqueiros, inanciado pelo programa PROMAR (Eixo 4/GAC Barlavento), 1) saber se a maturação sexual das cavalas no Algarve se processava abaixo do tamanho mínimo legal de desembarque (20 cm); 2) aumentar o conhecimento quanto ao perfil nutricional desta espécie, e por último, 3) envolver todas as partes interessadas, desde pescadores aos consumidores, na promoção do seu consumo. A cavala, cujo nome científico é Scomber colias (anteriormente designada por Scomber japonicus) é das espécies mais abundantes na costa portuguesa, que era até há bem pouco tempo das mais desaproveitadas, pois, por não ter um grande valor económico, era muitas vezes rejeitada ao mar. A sua utilização para consumo humano é ainda baixa, embora seja consumida em fresco, sobretudo no Verão e em conservas e congelada ao longo de todo o ano. A cavala é também usada como isco nos covos para o polvo e em algumas pescarias com aparelhos de anzol, e mais recentemente, como alimento de atuns nas armações algarvias e andaluzas. Depois de mais de seis décadas como a segunda espécie mais desembarcada, a cavala é desde 2012, mercê do declínio da sardinha, a espécie que mais se transaciona nas lotas nacionais e algarvias. E, apesar do baixo preço de primeira venda, cerca de 0,26€/kg, a cavala representou em 2014, a sétima espécie com maior valor económico no Algarve.

Discards from experimental trammel nets in southern European small-scale fisheries

Trammel net discards in four southern European areas were considerable, with a total of 137 species (79.7% of the total) discarded 65, 105, 46 and 32 species in the Basque country (Spain), Algarve (Portugal), Gulf of Cadiz (Spain) and Cyclades islands (Greece), respectively. The overall discard rate in terms of catch numbers ranged from 15% for the Cyclades to 49% for the Algarve, with the high discard rate for the latter due largely to small pelagic fishes. Discards in the four areas consisted mainly of Trisopterus luscus (Basque country), Scomber japonicus (Algarve), Torpedo torpedo (Cadiz) and Sardina pilchardus (all three areas), and Diplodus annularis in the Cyclades. Strong seasonal variation in discarding was found, reflecting differences in metiers and the versatility of trammel nets as a gear. Discarding, both in terms of numbers of species and individuals decreased with increasing inner panel mesh size. The main reasons for discarding were: (1) species of no or low commercial value (e.g. Scomber japonicus; Torpedo torpedo), (2) commercial species that were damaged or spoiled (e.g. Merluccius merluccius), (3) undersized commercial species (e.g. Lophius piscatorius), and (4) species of commercial value but not caught in sufficient quantities to warrant sale (e.g. Sardina pilchardus). A decrease in soak time together with the appropriate choice of mesh sizes could contribute to a reduction in discarding and to improved sustainability and use of scarce resources in the small-scale, inshore multi-species fisheries of southern Europe. (C) 2007 Elsevier B.V. All rights reserved.

Quantifying the roles of competing static gears: comparative selectivity of longlines and monofilament gill nets in a multi-species fishery of the Algarve (southern Portugal)

Fishing trials with monofilament gill nets and longlines using small hooks were carried out in Algarve waters (southern Portugal) over a one-year period. Four hook sizes of "Mustad" brand, round bent, flatted sea hooks (Quality 2316 DT, numbers 15, 13, 12 and 11) and four mesh sizes of 25, 30, 35 and 40 mm (bar length) monofilament gill nets were used. Commercially valuable sea breams dominated the longline catches while small pelagics were relatively more important in the gill nets. Significant differences in the catch size frequency distributions of the two gears were found for all the most important species caught by both gears (Boops boops, Diplodus bellottii, Diplodus vulgaris, Pagellus acarne, Pagellus erythrinus, Spondyiosoma cantharus, Scomber japonicus and Scorpaena notata), with longlines catching larger fish and a wider size range than nets. Whereas longline catch size frequency distributions for most species for the different hook sizes were generally highly overlapped, suggesting little or no differences in size selectivity, gill net catch size frequency distributions clearly showed size selection. A variety of models were fitted to the gill net and hook data using the SELECT method, while the parameters of the logistic model were estimated by maximum likelihood for the longline data. The bi-normal model gave the best fits for most of the species caught with gill nets, while the logistic model adequately described hook selectivity. The results of this study show that the two static gears compete for many of the same species and have different impacts in terms of catch composition and size selectivity. This information will I;e useful for the improved management of these small-scale fisheries in which many different gears compete for scarce resources.

Reducing discards in a demersal purse-seine fishery

Fisheries bycatches and discards constitute a significant problem in many fisheries worldwide. Unlike the pelagic purse-seine, the demersal purse seine usually targets high commercial value demersal species such as sea breams ( e. g., Diplodus spp., Pagellus spp., Sparus aurata) and the European sea bass ( Dicentrarchus labrax), while discards consist mainly of pelagic species and juveniles of the above mentioned species. In order to evaluate the efficiency of a selectivity device in reducing bycatch and consequently of discards in a demersal purse seine fishery, experimental deployments were carried out. The bycatch reducing device (BRD) consisted in the use of a panel of diamond-shaped mesh netting of 70 mm stretched mesh in the posterior part of the purse seine. Data from 61 experimental fishing trials allowed the evaluation of discards, with Scomber japonicus, Boops boops, Sardina pilchardus, Diplodus bellottii and Belone belone being the main discarded species. The mean discard ratio per set was 0.49 (+/- 0.30 standard deviation). The causes for discarding were also identified, with low commercial value being the most important reason. The results of the trials with BRD, were promising, with an average of 49% (+/- 24%) of the fish escaping per set, especially from those species that are most discarded. Overall, the use of this method for reducing discards can be considered positive for the following reasons: there is no need for structural modification of the fishing gear, the BRD is easy to deploy, and it is efficient in terms of species, sizes and quantities of fish that manage to escape. It therefore has significant benefits for the demersal purse seine fishery and possibly for other "metiers" as well.

Utilização do ciclo luminoso como indutor do crescimento de camarões Penaeus japonicus

Dissertação de mest. em Aquacultura, Unidade de Ciências e Tecnologias dos Recursos Aquáticos, Univ. do Algarve, 1997

Valorização de recursos pesqueiros: Cavala algarvia

O Centro de Ciências do Mar da Universidade do Algarve pretendeu com a aplicação do projeto Cavala Algarvia ao Sotavento Algarvio, com financiamento do programa PROMAR (Eixo 4/GAC Sotavento), e apoio da Associação de Armadores de Pesca da Fuzeta (AAPF) e da Organização de Produtores de Pesca do Algarve (Olhãopesca), conhecer melhor diversos aspetos da pesca da cavala (Scomber colias), o seu perfil nutricional, a sua dieta alimentar e promover o seu consumo mediante a realização de eventos em parceria com diversas entidades da região, nomeadamente a Escola de Hotelaria e Turismo do Algarve do Turismo de Portugal IP (EHTA), Docapesca SA, RUA FM Rádio Universitária do Algarve, a Conserveira do Sul, Algarfresco, Gobius Comunicação e Ciência, Câmaras Municipais de Loulé, Faro, Olhão, Tavira, Vila Real de Santo António e Castro Marim e Marinas de Vilamoura. Da análise das estatísticas de pesca conclui-se que a cavala é capturada essencialmente pela Rússia, Marrocos e Portugal, sendo que desde 2012 é a espécie mais capturada em Portugal e também no Algarve, ultrapassando a sardinha. No Algarve são capturadas mais de 7000 toneladas por ano, sendo Olhão o porto principal de desembarques com mais de 70% das capturas algarvias, seguido de Quarteira e Portimão. O preço médio de venda em lota continua muito baixo, cerca de 0,26€/kg, pois o consumo para alimentação humana desta espécie continua reduzido, sendo a cavala essencialmente utilizada para isco, na pesca do polvo, e para alimentar atuns nas armações nacionais e estrangeiras.

Diet of the blue marlin, Makaira nigricans, off the south coast of Portugal

The blue marlin, Makaira nigricans (Istiophoridae), is a large, top predator with a worldwide distribution whose feeding ecology is still unknown in the northeast Atlantic. The stomach contents of 24 Atlantic blue marlin, caught by the Big Game fishing fleet (between 2007 and 2010) off the south coast of Portugal, were studied. All marlin fed exclusively on pelagic fish, with a total of 180 prey items recorded, belonging to 6 identified species. The most important family in the blue marlin diet was Scombridae, representing 70% of the total prey items. Among the Scombridae, the chub mackerel, Scomber colias, was the most important prey species (47.9% by weight, 51.1% by number, 58.3% by frequency of occurrence). The length of prey found in the stomachs ranged from 136 to 727 mm in length, and a significant positive correlation was found between prey and blue marlin size. Our results suggest that in this geographical area (NE Atlantic) marlin feed on a small spectrum of species, with a preference for foraging on seamounts.

Catches of the sport fishing competitions along the Algarve coast (Portugal): species, sizes, catch rates, and trends

Background. Stocks of many marine fishes are in decline and a number of studies suggest that for some species the impact of recreational angling may be important. To date, only recreational (leisure) fishing surveys have been conducted in Portugal, with no studies on beach angling competitions, dynamically increasing in number over the past 10 to 20 years. In view of the above, we decided to evaluate the impact of such events on the Algarve coast (southern Portugal) in terms of the abundance, diversity, and respective weight of fish species caught and outline some conservation measures and recommendations for the management of the targeted species. Materials and methods. Participants of 22 angling competitions taking place between February and June 2007 were surveyed. In each competition a random sample of anglers was interviewed, and the specimens caught by each participant were identified, weighed, and measured. Results. Thirteen taxa belonging to eight families were identified, and the most common were: garfish, Belone belone (Linnaeus, 1761); mullets, Mugilidae (not identified); and mackerels, Scomber spp. A total of 563 specimens were sampled, totalling 75.4 kg of weight, with the average catch per angler weighing 0.5 +/- 0.05 SE (n = 153) kg. Differences were also observed between the length at first maturity (L(50)) of the specimens caught and their respective Minimum Landing Size (MLS) and Allowed Minimum Size (AMS), most particularly in the case of the European seabass, Dicentrarchus labrax (L.), with almost all individuals caught measuring below the species-specific L50. Analysis of time series of competition results (1996-2009) showed no evidence of a decrease in catches or in mean weight. Conclusion. Based on the results we propose that the AMS for beach angling competitions should be increased to the MLS in order to prevent the capture of juvenile fishes, especially the sea bass. Future studies should address the size selectivity of the hooks used in beach competitions, with a view to the implementation of a minimum hook size for competitions.