Communications orales
- 2010
- Camanho, A.S., Oliveira, M.M., Gaspar, M.B. Technical and economic efficiency analysis of the Portuguese artisanal dredge fleet. ALIO-INFORMS Joint International Meeting, 6 a 9 de Junho 2010, Buenos Aires.
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This paper explores the efficiency of the Portuguese dredge fleet using Data Envelopment Analysis. The technical efficiency analysis included fixed and variable inputs, and the outputs were the amount of each bivalve species landed. Using data on the prices of each species, revenue efficiency was also estimated. This approach enables a graphical representation of the performance of the vessels in two dimensions, and the specification of targets for inefficient vessels.
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- Gaspar, M.B.,2010. Observatório de las Pesquerías Artesanales. Jornada sobre la Gestión Sostenible de la Pesca Artesanal, 25 de Febrero 2010, Aquário de Gijón, Gijón.
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- Gaspar, M.B., 2010. La pesca artesanal en portugal: importancia y gestión. Jornada sobre la Gestión Sostenible de la Pesca Artesanal, 25 de Febrero 2010, Aquário de Gijón, Gijón.
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- Gaspar, M.B., 2010. Principais desafios que se colocam à gestão da pequena pesca. Seminário "Pesca Artesanal em Portugal: Reflexões e Desafios", 13 Novembro 2010, Sesimbra.
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- Félix-Lamas, J., 2010. Diversificação socioeconómica na pesca artesanal. Seminário "Pesca Artesanal em Portugal: Reflexões e Desafios", 13 Novembro 2010, Sesimbra.
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- Chapela-Pérez, R., 2010. Diversificación socioeconómica en la pesca artesanal en el proyecto PRESPO. IV conferencia internacional sobre diversificación socioeconómica en la pesca artesanal, 26 Octubre 2010, Vigo (Spain) .
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- Lourenço, S., Moreno, A., Narciso, L., Pereira, J., 2010. Seasonal trends of reproductive cycle of Octopus vulgaris in two environmental distinct coastal Areas. 8th International Symposium Cephalopods - Present and Past, UniversiTy of Burgundy, 30 August to 3 September, Dijon, France.
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Octopus vulgaris is a bottom-dwelling species with pelagic paralarvae. The species is widely distributed over mainland shelf waters, as well as in distant oceanic islands and seamounts of the eastern Atlantic, with mature individuals found all year around, although with specific intensive breeding seasons. The paralarval phase can represent up to 25% of the longevity of the species and is highly sensitive to environmental conditions, including water mass characteristics and food availability. Data on maturation and other biological parameters collected between January 2007 and December 2009 are used to define breeding seasons for octopus landed by artisanal fisheries in two oceanographically distinct Portuguese coastal areas: the northwest (western Iberia upwelling ecosystem) and the south (Gulf of Cadiz ecosystem). In order to identify the specific breeding seasons we follow monthly the proportion of mature specimens and the maturity ogive characteristics as population parameters, as well as the Gonad-Somatic Index and the Hayashi Index as biological parameters. Mature males and females are found all year around. The proportion of mature females presents important breeding indications in both coastal areas but at different timings. The indication of different breeding seasons between geographical areas is confirmed by the monthly evolution of female gonad-somatic indices. Size at maturity of both females and males is also studied in order to evaluate reproductive differences between both areas. The spawning strategies of octopus on the Portuguese coast and other upwelling systems show that the species is capable of adjusting its population dynamics in terms of spatial and temporal optimisation of the survival of the planktonic paralarvae.
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- 2009
- Oliveira, M.M., Camanho, A. S., Gaspar, M.B., 2009. Efficiency analysis of Portuguese artisanal dredge fleet. XI European Workshop on Efficiency and productivity Analysis ( EWEPA), Pisa, Italy, 23-26 June 2009.
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This paper presents the efficiency analysis of commercial clam fishery fleets operating in
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- Vasconcelos, P., Pereira, A. M., Constantino, R., Barroso, C. M., Gaspar, M. B., 2009. Growth of the purple dye murex (Bolinus brandaris) marked and released in a semi-intensive fish culture earthen pond. Estuarine and Coastal Sciences Association (ECSA’45), 30 August - 4 September 2009, Trinity College, Dublin, Ireland.
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In Portugal, the purple dye murex (Bolinus brandaris) is commercially exploited by artisanal fisheries along the Algarve coast, mainly in the Ria Formosa lagoon (southern Portugal). This muricid gastropod is greatly appreciated shellfish with high commercial value in the local seafood market (reaching first sale values around 20 − 25 €/kg). Moreover, as local demand for shellfish products has augmented and the commercial value of B. brandaris has increased markedly in recent years, this species generates expectations as potential candidate for molluscan aquaculture. In this context, this study reports the growth rate of B. brandaris, estimated through mark-recapture experiments in a semi-intensive fish culture earthen pond of the IPIMAR’s Aquaculture Research Station. A total of 1067 specimens (shell length = 43.38 ± 8.06 mm, range = 14.55 − 78.39 mm) were marked with Dymo® tape tags (fixed with cyanoacrylate glue and covered with epoxy glue). Marked specimens were recaptured using a traditional fishing gear locally designated as “wallet-line” and by scuba diving. After a period at liberty (interval between marking and recapture) that varied between two months and slightly over two years, 288 individuals were recaptured (shell length = 67.37 ± 6.23 mm, range = 45.29 − 88.56 mm), corresponding to a recapture rate of 27.0%. At recapture, only one specimen had lost the tag and all the remaining tags were intact and legible. Mean growth rates obtained were 0.9 ± 1.0 mm in shell length / month and 0.7 ± 0.7 g in total weight / month. On average, individuals deposited 2.3 ± 3.2 shell bands along the body whorl per year. Growth rates presented high inter-individual variability and an expected decreasing trend with shell length at marking. This study provides baseline data for the management of the purple dye murex fishery and useful information to assess the potential of B. brandaris as a new species for molluscan aquaculture. This work was partially funded by the EU project “Desarrollo Sostenible de las Pesquerías Artesanales del Arco Atlántico - PRESPO” (Programme INTERREG IV B - UE, ERDF).
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- Gaspar, M., 2009. Comunidades Piscatórias: Importância da pesca artesanal. Seminário Turismo de Pesca e Mar, Ilhavo, Museu Marítimo de Ilhavo, 2 de Dezembro, 2009.
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