IPMA - DMRM - Relatórios Científicos e Técnicos do IPMA
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- ABUNDANCE, DISTRIBUTION AND POPULATION STRUCTURE OF THE COMMON COCKLE Cerastoderma edule (Linnaeus, 1758) IN RIA DE AVEIRO, PORTUGALPublication . Maia, Francisco; Ruano, Francisco; Gaspar, Miguel; Instituto Português do Mar e da Atmosfera, I.P.The common cockle (Cerastoderma edule) is currently the most important shellfish resource exploited in Ria de Aveiro. In recent years, surveys have been conducted by the Portuguese Institute of the Sea and Atmosphere to provide data on stock status for management purposes. The present work presents the results of the 2019 cockle survey, as well as the stock trends over the years. Results revealed that Cerastoderma edule is well established in all fishing areas of the Ria de Aveiro. The major cockle beds were found in Cale da Moacha (1951.0 g/m2 at 2.5 m depth), Mira Channel (1519.4 g/m2 at 3.4 m depth) and Ílhavo Channel (1192.8 g/m2 at 2.0 m depth). These three production areas were responsible for about 60% of the total cockle biomass caught. However, the cockle fishing yields were still remarkably lower than those registered in the 2007 survey, which may compromise the sustainability of the stocks and seriously jeopardize future catches and incomes
- ANÁLISE DA AMOSTRAGEM BIOLÓGICA DE PESCADA (Merluccius merluccius) PROVENIENTE DAS CAMPANHAS DEMERSAIS DE OUTONO ENTRE 1990 E 2013Publication . Costa, Ana Maria; Instituto Português do Mar e da AtmosferaThis work was carried out in order to compile the results obtained with the biological sampling of hake from the information collected in demersal autumn surveys conducted from 1990 to 2013 under the PNAB/EU DCR-Data Collection Regulation. 71817 individuals were analyzed and three geographical areas were considered, northwest (NW), south west (SW) and south (S). In each zone the length distributions and the sex ratio, with their distributions in depth, were studied; the percentage of maturity stages, the maturity ogives and the length at the 1st maturity were also estimated for each zone. There was a predominance of males in the length classes below 40 cm and of females above 50 cm. The values of the L50 varied in the NW coast between 21 cm (in 2008) and 74.9 cm (in 1994), in the SW coast between 18.6 cm (in 2008) and 51.5 cm (in 1990) and in the S coast between 11.3 cm (in 2010) and 61.7 cm (in 1996), showing a slight decreasing trend in recent years.
- AQUACULTURA MULTI-TRÓFICA INTEGRADA EM TANQUES DE TERRAPublication . Maria Emília Cunha; Quental-Ferreira, Hugo; Ribeiro, Laura; Moreira, Márcio; Soares, Florbela; Caetano, Miguel; Ferreira, Pedro Pousão; Instituto Português do Mar e da Atmosfera, I.P.Integrated multi-trophic aquaculture (IMTA) is the combined cultivation of animals that need food from external origins together with organisms that extract organic and inorganic matter from the rearing environment creating a balanced production system. This paper presents the results obtained during the first year of an integrated multi-trophic production of gilthead sea bream (Sparus aurata) and several sea-breams species (Diplodus sargus, D. cervinus, D. puntazzo, and D. vulgaris), Portuguese oyster (Crassostrea angulata) and a sea cucumber (Holothuria mammata) grown in earthen ponds in order to evaluate the adaptability of these species to integrated cultivation, their growth performance and the most suitable structures for oyster farming in ponds. Animal biomass produced per cubic meter per tank at the end of this experiment were respectively 0.4 kg and 0.6 kg in simple polyculture and multi-trophic polyculture. It was observed in tanks of simple polyculture that the concentrations of nitrate + nitrite and phosphate were higher comparatively to the multi-trophic polyculture that showed higher values of chlorophyll a, and total organic carbon and total organic nitrogen. Oysters daily growth rates varied between 10.3% and 7.2% and were higher during the summer - autumn when mortality was also higher. The microbiological quality of the oysters in the rearing tanks was better than the neighboring oyster beds at Ria Formosa coastal lagoon from where the water comes from suggesting the existence of an intermediate purification process of the inlet water. From the tested oysters farming structures, the suspended lanterns showed better results in terms of survival. The fish species showing better adaptation to growth in earthen ponds were Sparus aurata and Diplodus cervinus. D. cervinus seemed to be better adapted (growth and survival) to multitrophic integration.The external parasites that affect the fish gills were Microcotyle and Lamellodiscus and there were no differences in prevalence and/or incidence between the two rearing systems. Lamellodiscus affected the larger fish and Microcotylethe smaller ones. In the rearing conditions of the experiment sea cucumbers had very low survival.
- AUMENTO DA EFICIÊNCIA ENERGÉTICA EM ARRASTÕES COSTEIROS ATRAVÉS DA UTILIZAÇÃO DE REDES DE ARRASTO COM FIBRAS DE ELEVADA TENACIDADEPublication . Parente, Joaquim; Fonseca, Paulo; Henriques, Victor; Campos, Aida; Instituto Português do Mar e da AtmosferaTrawling is a fishing technique associated with an intensive consumption of fuel and, consequently, the profit margin of a commercial trawling vessel is very dependent on the variations in the price of diesel. The share of fuel in the total costs of Portuguese coastal trawlers may be as high as 40%. One way of reducing consumption is to decrease the overall drag resistance of the trawl by introducing changes to the trawl gear. Within the framework of the project CONSUPESCA - Reduction of Energy Consumption in Trawling Fisheries, financed by the PROMAR program, changes were introduced in a gear typically used by coastal trawlers operating off the main port (Aveiro) of the centre region of Portugal. The trawl gear originally built in braided polyethylene was redone, incorporating high-tenacity fibres and slightly increasing the front panels’ mesh size. The immediate result was a 30% decrease in twine area, leading to a significant reduction in fuel consumption per unit area of the gear’s mouth, ranging from 13 to 21% for trawl velocities ranging from 3.6 to 4.4 knots. The qualitative assessment made by the captain on the performance of the modified gear was very positive, with a less demanding engine effort within the range of commercial trawling speeds.
- CARACTERIZAÇÃO DA PESCARIA DE GALEOTA-MENOR (Ammodytes tobianus Linnaeus, 1758) NA RIA DE AVEIRO, PORTUGALPublication . Maia; Francisco; Instituto Português do Mar e da Atmosfera, I.P.In the Spring and Summer of 2002 an experimental fishing study was carried out in Ria de Aveiro to determine the impact of the fishing gear, “Rede-da-Galeota”, on its target species the small sandeel Ammodytes tobianus. Catch data showed that this fishing net has the potential to affect both target and non-target species, with negative consequences for the local marine ecosystems. Survey data analysis revealed that the “Rede-da- Galeota” retained 9 by-catch species, 7 of which with commercial interest, namely the sardine (Sardina pilchardus), the thinlip grey mullet (Liza ramada), the thicklip grey mullet (Chelon labrosus), the golden grey rangon) and the european green crab (Carcinus maenas) . The by-catch species made up to 15% of the total catch and the remaining 85% were composed mainly of juvenile specimens of A. tobianus (71,3%). All the commercial bycatch specimens caught by “Rede-da-Galeota” were smaller than the minimum allowed landing sizes. Taking into consideration the poor size selective properties of this fishing net, it is recommended to maintain the “Rededa- Galeota” in the list of prohibited fishing gears and practices in Ria de Aveiro, in compliance with the administrative rule Portaria n.º 563/90 of July 19th.
- CICLO REPRODUTIVO, ÍNDICE DE CONDIÇÃO E TAMANHO DE PRIMEIRA MATURAÇÃO SEXUAL DA AMÊIJOA-JAPONESA Ruditapes philippinarum (ADAMS & REEVE, 1850) NA RIA DE AVEIRO, PORTUGALPublication . Maia, Francisco; Instituto Português do Mar e da AtmosferaThis study reports the reproductive cycle, condition index and the size at first maturity of the Manila clam Ruditapes philippinarum in Ria de Aveiro (Portugal). The reproductive cycle was monitored over 1-year period, from January to December 2013, and the development of the gonads was classified into six successive maturity stages according with the microscopic observation of histological sections of the gonads. Spawning extended from April to October, with a peak by the end of summer (August and September). The condition index showed a distinct seasonal pattern which appear to be related to the reproductive cycle. The size at first sexual maturity was attained at a shell length of 20.0 mm, within the first year of life. Additionally, the reproductive strategy and the growth parameters were compared between the Manila clam and its congeneric native species the Grooved carpet shell clam (Ruditapes decussatus).
- CONSERVAÇÃO EM REFRIGERADO DE FIAMBRES DE CORVINA E DOURADA EMBALADOS EM ATMOSFERA MODIFICADAPublication . Patriarca, J.; Ribeiro, A.T.; Silva, H.; Vieira, H.; Teixeira, B.; Rodrigues, M.J.; Gil, M.; Pousão-Ferreira, P.; Mendes, R.; Instituto Português do Mar e da AtmosferaThe search for healthier food products has increased the development of novel fish-based functional foods. In the present work the quality changes during refrigerated storage of meagre and sea bream hams enriched with dietetic fibers and packaged in modified atmosphere (30 % CO2 / 70 % N2) were evaluated. The fish hams had a good sensory acceptance and in microbiological terms were acceptable until at least 20 days. The consumption of 25 grams of meagre ham guarantees 6.0 % and 4.8 % of the DDR of fiber and EPA+DHA, respectively, while seabream ham provides 7.2 % and 17.7 %. The meagre and seabream hams with dietary fibers are two hypocaloric products very interesting nutritionally for a market of consumers demanding fish-based products that also promote health and well-being.
- CONTROL OF SEAFOOD LABELLING IN PORTUGALPublication . Mendes, Rogério; Silva, Helena; Instituto Português do Mar e da Atmosfera, I.P.Project Labelfish – the “Atlantic Network on Genetic Control of Fish and Seafood Labelling and Traceability” is a European project that aims to set up a network of entities with an interest in the use of standardised, innovative analytical techniques to control genetic traceability and labelling of seafood products. Within this project one of the objectives is the analysis of fish labelling in markets of the Atlantic region (Portugal, Spain, France, United Kingdom and Ireland). This report summarizes the level of implementation of seafood labelling control across the Portuguese seafood sector. Main areas focused in the report include, (i) identification of the bodies involved in the control and evaluation of seafood labelling, (ii) assessment of the experience and results of the Portuguese administration in relation with the effective control of seafood labelling, (iii) survey of annual control plans and modus operandi and (iv) statistics of level of compliance.
- Discards from the Portuguese bottom otter trawl operating in ICES Division 27.9.a (2004-2015)Publication . Fernandes, Ana Cláudia; Prista, Nuno; Azevedo, Manuela; Instituto Português do Mar e da Atmosfera, I.P.This document compiles the information available on discards from Portuguese vessels operating with bottom otter trawl (OTB) in the Portuguese ICES Division 27.9.a, estimated by IPMA for the period 2004- 2015. These discards include species from the stocks assessed in ICES assessment Working Groups and species commercially important at national level. The samples were collected by the onboard sampling programme of the National Programme for Biological Sampling (PNAB/EU DCF), integrated in the National Data Collection Framework . The onboard sampling programme, estimation algorithms and data quality assurance procedures are described and results for two fisheries provided: the crustacean bottom otter trawl fishery (OTB_CRU) and the demersal bottom otter trawl fish fishery (OTB_DEF). Estimates of discard volume and length composition are provided for the ‘year, fishery, species’ combinations where they are frequently observed ( 30% of sampled hauls). Results show that although there’s a large number of species discarded, the number of species frequently discarded is very low (7% in OTB_CRU and 4% in OTB_DEF). Mean number of discards per haul is calculated for all species that occurred in discards and analysis of length compositions are displayed for selected species. Analyses of the combined results indicates that a large part of the species selected for this work are either absent in discards or very rarely discarded. Indications are given on possible discarding reasons and on the discard estimation methodology to be developed for less frequent species and for other Portuguese fleet components.
- EFEITO DA ARMAZENAGEM EM REFRIGERADO NA QUALIDADE DE FIAMBRE DE CORVINA COM FIBRAS DIETÉTICAS EMBALADO EM VÁCUO E EM ATMOSFERA MODIFICADAPublication . Patriarca, J.; Ribeiro, A.T.,; Silva, H.; Vieira, H.; Teixeira, B.; Rodrigues, M.J.; Gil, M.; Pousão, Ferreira P.; Mendes, R.; Instituto Português do Mar e da AtmosferaThe development of novel fish-based functional foods is increasing due to consumer’s search for healthier food products to create a daily balanced diet. The final goal of the present work was to evaluate the quality during refrigerated conditions of meagre ham enriched with dietetic fibers and packaged in vacuum and in modified atmosphere (20% or 40% CO2). The proximate chemical composition indicated that meagre ham had 76.7% of moisture, 5.1% of fat, 3.9% of ash, 11.1% of protein and 3.2% fiber. The 55-day stability study revealed that the fish ham‘s shelf life did not vary with different packaging conditions, but was limited by microbial growth. Its quality was acceptable up to thirteen days in refrigerated conditions for all packages used.