Abnormal domination of gilt sardine (Sardinella aurita) in the middle shelf ichthyoplankton community of Gulf of Cádiz (SW Iberian Peninsula) in summer: related changes in the hydrologic structure and implications in the larval fish and mesozooplankton assemblages finded.

Abstract

During the yearly ‘Ictio.Alborán-Cádiz’ (1994–1997) multidisciplinary oceanographic surveys, the eggs and larvae of anchovy (Engraulis encrasicolus) are generally the dominant in the middle shelf ichthyoplankton community of the Gulf of Cádiz in summer. In the 1995 survey a notorius change have detected: the maximum localized abundance for ichthyoplanktonic components of gilt sardine (Sardinella aurita) have multiplied x 10 (eggs) and x 20 (larvae) the anchovy’s components. In this paper we discuss the observed changes in the hydrologic structure and in the larval fish and mesozooplankton assemblages (cluster analysis).