February 1st to 5th 2016
Olhão, Portugal
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Spatial protection and size composition of soft bottom fish communities: the case of the Luiz Saldanha Marine Park (Portugal)

Scientific Exhibition
Natural Resources
Wednesday, February 3, 2016 -
18:30 to 20:00

Sousa, I. 1 Horta e Costa, B. 2 Gonçalves, J.M.S. 3 Gonçalves, E.J. 4 Erzini, K. 5

1Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
2Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
3Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
4MARE–Marine and Environmental Sciences Centre, ISPA–Instituto Universitário, R. Jardim do Tabaco 34, 1149-041 Lisboa, Portugal
5Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal

Marine protected areas have been increasingly recognized as conservation and fisheries management tools, with the size composition of fish assemblages being one of the strongest indicators of protection measures. Size-based metrics are increasingly being used as indicators of anthropogenic impacts and marine reserves performance. We analyzed size-based metrics of one soft bottom fish assemblage within a multiple zoning MPA in the north-eastern Atlantic, the Luiz Saldanha Marine Park (Portugal). Data were collected by trammel net in three protection level areas, during the implementation period and for three years after full implementation of the marine park. The fish assemblage was found to be dominated by the families Soleidae, Triglidae and Rajidae. Two indexes were tested to evaluate the effect of protection on the size composition of this fish assemblage, over time and between the three protection levels. One used the maximum size described per species and the other looks at the percentage of ‘mega-spawners‘ in the catch, i.e. fish of a size larger than optimum length plus 10%. Both indexes proved to be adequate to identify differences in size composition in this case-study. Results indicate different trends both in space and time according to different species, with some species showing positive trends that are likely related to protection.
keywords: 
Marine Protected Areas, Size-based metrics, Soft bottom fishes, Spatial protection

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