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Juvenile Anchovy, Engraulis Encrasicolus, HabitatConditions and Daily Growth in the CentralMediterranean SeaG. Basilone 1 , A. Bonanno 2 , B. Patti 2 , S. Gancitano 1 , L. Caruana 2 , M.Bonsignore 2 , S. Aronica 2 , G.Tranchida 21, Institute for Coastal Marine Environment, CNR, Mazara del Vallo (TP), Italy2, Institute for Coastal Marine Environment, CNR, Capo Granitola (TP), Italywalter.basilone@irma.pa.cnr.itAbstractThis study investigates the juvenile anchovy life stage in their habitat during therecruitment period. Daily otolith age readings permitted to evaluate the birthdatedistributions which, compared with the spawning effort obtained from monthly samples,highlighted a higher mortality of larvae and postlarvae during the first part ofthe spawning period. Differences in the growth rate were also recorded during thefirst half of the spawning season by measuring microincrements and backcalculatingthe length at age. The link between mortality and growth rates has been discussedalong with temperature as the main habitat feature regulating growth in the postlarvaland juvenile phases. Data were collected in the Straits of Sicily in three multidisciplinarysurveys (2001, 2004 and 2005), while growth performances and the birthdateanalyses were carried out on data from the 2005 survey. The oceanographic parametersand juvenile spatial distributions, showed a negative linear relationship betweenwater temperature and juvenile anchovy average length for each trawl suggesting apreference for smaller organisms to inhabit warmer waters. The birthdate peak wasobserved between the end of July and early August with individual ages ranging from46 to 186 days. The obtained mean growth was 0.4 mm·d −1 whilst the daily backcalculatedgrowth rates range between 0.4 and 1.06 mm·d −1 .The estimated mortalityrate for juvenile anchovy in the age range 60-100 days old, was 0.03 d −1 .1 IntroductionAnchovy fishery represents the main worldfishing resource and constitutes almost30% of the total Mediterranean fish production[1, 2]. Clupeoid fish populations,especially anchovies and sardines,exhibit large fluctuations in abundancein several distributed areas in the world[3, 4, 5]. In the study area, acoustic andichthyoplankton-based biomass evaluationmethods showed how the high interannualvariability in biomass levels weremainly associated to environmental variability[6, 7, 8].Growth and mortality, the principal processesthat determine population dynamicsand the high variability in recruitment success,are generally linked to the mortalityof early life stages from hatching to recruitmenttime. Estimation of these lifehistory parameters at different life stages