IMPORTÂNCIA DAS FASES LARVARES E PÓS-LARVARES DE DONAX TRUNCULUS NA GESTÃO DO RECURSO NA COSTA ALGARVIA

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The importance of the pelagic larval phase of the wedge shell Donax trunculus (L.): implications for the management of the fishery

Publication . Pereira, Alexandre Miguel Moura; Gaspar, Miguel Baptista; Felpeto, Josefina Méndez; Chícharo, Luís Manuel Zambujal

The wedge shell, Donax trunculus, inhabits high energy environment of exposed sandy beaches from the Atlantic coast of France to Senegal. Like all Donacidae, it is relative small, flat-shaped with elongated solid shells. It is a highly demanded and valuable species mainly in Algarve, with the dredge fleet increasing the pressure on species stocks. In 1986 the Portuguese Institute for the Ocean and Atmosphere (IPMA) initiated a bivalve survey program to evaluate the stock status of species with economical valuable but always on the adult population. Since then, several managing measures were implemented to guarantee bivalves’ sustainable exploitation. Despite the available information on the abundance and distribution of the wedge shell along the Algarve coast, no information on the larval planktonic phase is available. To fill in this gap, the present study aimed at obtaining, for the first time information on the broodstock condition and on the pelagic phase of the wedge shell in the Algarve coast.

2013Doctoral thesis

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Larval hatching and development of the wedge shell (Donax trunculus L.) under increased CO2 in southern Portugal

Publication . Pereira, Alexandre Miguel; Range, Pedro; Campoy, Ana; Oliveira, Ana Paula; Joaquim, Sandra; Matias, Domitília; Chícharo, Luís; Gaspar, Miguel

Noticeable changes in global temperatures, climate and ocean carbon chemistry are the result of carbon dioxide increase in the atmosphere. This increase has been mitigated by the oceans capacity to absorb one-fourth of the carbon dioxide in the atmosphere, although this CO2 intake affects oceans carbonate chemistry [i.e., ocean acidification-(OA)]. The detrimental effect of OA in the development and shell formation has been studied in several species of bivalves, although no information is available on the wedge shell Donax trunculus, a gastronomically appreciated species and an important economical resource in several southern European countries. We evaluated the effect of pCO(2) increase on hatching and early life stages of D. trunculus, considering two ocean acidification scenarios (Delta pH -0.3 and Delta pH -0.6). Our results showed that elevated pCO(2) caused a delay in hatching into D-larvae and reduced larvae survival. In the extreme scenario (Delta pH -0.6), some trochophore larvae persisted to day 9 of the experiment and more abnormal larvae were produced than in the Delta pH -0.3 and control treatments. At day 5, normal veligers under extreme acidification were smaller than in other treatments, but by day 9, these differences were attenuated and the average size of normal D-larvae varied inversely to the pH gradient. Possible underlying mechanisms for these complex response patterns are discussed, including the existence of phenotypic plasticity or genetic pre-adaptive capacity in this D. trunculus population to cope with future environmental changes.

2016-07Journal article

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