ROLE OF GUADIANA ESTUARINE WETLANDS AS A NURSERY AREA FOR FISH UNDER CLIMATE CHANGE & ANTHROPOGENIC PRESSURES. UNDERSTAND, MODEL AND DEVELOP ECOHYDROLOGICAL RESTORATION TECHNIQUES

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Environmental factors affecting larval fish community in the salt marsh area of Guadiana estuary (Algarve, Portugal)

Publication . Gonçalves, Renata; Correia, Ana Dulce; Atanasova, Natasa; Teodosio, Maria; Ben-Hamadou, Radhouan; Chicharo, Luis

Salt marsh areas in the Guadiana estuary are important nursery sites for many fish species of commercial and recreational value. More effective protection measures should be adopted as the area is highly affected by anthropogenic and natural threats. Studying larval fish communities in these impacted nursery areas will be relevant to the management of local ecosystems and to larval fish ecology in general. Spatial and seasonal distribution and the effect of environmental factors on the larval fish community of this ecosystem were studied for one year (April 2010 to March 2011). Larvae were sampled monthly in parallel with phytoplankton and zooplankton. Hydrological data and physical parameters were monitored. A decision tree model was used to assess the influence of environmental factors on the larval fish community. A total of 130 larvae and 1171 eggs were caught. Diplodus sargus, Sardina pilchardus, and Pomatoschistus microps were the most abundant larval fish species. The peaks of fish larvae abundance occurred in March and April. The output of the model demonstrates that the abundance of larval fish is determined by the abundance of eggs, zooplanktonic food, and water flood and flow. This study shows the importance of the Guadiana salt marsh as an area for fish nursery and highlights the need for conservation of this area.

2015-03Artigo científico

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Preliminary insight into winter native fish assemblages in guadiana estuary salt marshes coping with environmental variability and non-indigenous fish introduction

Publication . Goncalves, Renata; Teodosio, Maria; Cruz, Joana; Ben-Hamadou, Radhouan; Correia, Ana Dulce; Chicharo, Luis

This work aims to undertake a preliminary characterization of winter fish assemblages in the salt marsh areas of Guadiana lower estuary (South-East Portugal) and discusses the potential risks of habitat dominance by a non-indigenous species (NIS). To this effect, six field campaigns were carried out in four sampling sites during winter season targeting the collection of fish species. A total of 48 samples were collected. Individuals from seven different taxa (marine and estuarine) were collected, although the assemblage was dominated by two estuarine species—the native Pomatoschistus sp. (goby) and the NIS Fundulus heteroclitus (mummichog). Goby was the most abundant taxa in the majority of salt marsh habitats, except for one specific, marsh pool, where extreme environmental conditions were registered, namely high temperature and salinity. Such conditions may have boosted the intrusion of mummichog in this area. This species is well adapted to a wide range of abiotic factors enabling them to colonize habitats where no predators inhabit. Impacts of mummichog introduction in the Guadiana salt marsh area are still unpredictable since this is the first time they have been recorded in such high density. Nevertheless, in scenarios of increased anthropogenic pressure and, consequently, habitat degradation, there is a potential risk of mummichog spreading to other habitats and therefore competing for space and food resources with native species.

2017-10-26Artigo científico

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Entidade financiadora

Fundação para a Ciência e a Tecnologia

Número da atribuição

SFRH/BD/47985/2008