Estimated impact of the horizontal net opening in the calculation of abundance indices in the trawl survey = Incidenza della stima dell'apertura orizzontale della rete nel calcolo degli indici di abbondanza nei trawl survey medits

PALMAS, FRANCESCO;Pesci P;Buttu S;Atzori G;Secci M;SABATINI, ANDREA

2013-01-01

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Abstract

The effects of horizontal net opening in the calculation of abundance indices of Mullus barbatus (Linnaeus, 1758) (Osteichthyes: Mullidae) and Aristaeomorpha foliacea (Risso, 1827) (Crustacea: Decapoda) were investigated in the FAO Geographical Sub-Area 11. New measurements on the performance of the bottom trawl gear were collected in 2011-2012 in order to construct a predictive model of the horizontal net opening. The abundance indices were estimated and compared with an old predicted model. A high correspondence between the two sources of data has been found for M. barbatus, while for A. foliacea a difference in the absolute values for different years has been highlighted.