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Age, growth, and mortality of the karamote shrimp, Melicertus kerathurus (Forskål, 1775) [formerly: Penaeus k.], were determined for the native population in Amvrakikos Gulf (Ionian Sea; western Greece). Sampling was carried out on a monthly basis between June 1999 and May 2001. Carapace length ranged between 22 and 62 mm. Based on the carapace length frequency distribution, the Gulf population is composed mainly of individuals belonging to the first age class (0 and 1), and only a few from the other two expected age classes. Length frequency distributions and weight-at-age data were used to estimate the parameters of the Von Bertalanffy growth equations. For females, these were: CL ∞ = 69.704 mm, TL ∞ = 309.14 mm, W ∞ = 123.01 g, K = 1.062 year −1 , t 0 = 0.238 years. For males: CL ∞ = 62.658 mm, TL ∞ = 274.18 mm, W ∞ = 115.979 g, K = 1.253 year −1 , t 0 = 0 years. Von Bertalanffy parameters for pooled data were: CL ∞ = 59.695 mm, t 0 = 0 and K = 1.047 year −1 and TL ∞ = 246.79 mm, t 0 = 0.410 and K = 0.629 year −1 and W ∞ = 92.88 g based on TL. The overall length-weight relationship was: log W = −1.767 + 2.037 log TL (r 2 = 0.842, N = 5505). Total mortality Z and natural mortality M rates for combined sexes were 2.26 year −1 and 1.15 year −1 , respectively. The exploitation ratio E was estimated to be 49%. RÉSUMÉ L'âge, la croissance et la mortalité de la crevette caramote Melicertus kerathurus (Forskål, 1775) [précédemment : Penaeus k.] ont été déterminés pour la population autochtone du golfe d'Amvrakikos (mer Ionienne, ouest de la Grèce). Des échantillons ont été effectués mensuellement entre Juin 1999 et Mai 2001. La longueur de la carapace était comprise entre 22 et 62 mm. La fréquence de distribution de la longueur de la carapace montre que la population du golfe est surtout 4 ) Crustaceana 79 (1): 33-52 Also available online: www.brill.nl 34 ALEXIS CONIDES ET AL.composée d'individus de la 1 ère classe d'âge (0 et 1) et seulement de peu des deux autres classes attendues. La fréquence de distribution de la longueur et les données poids versus âge ont été estimées à partir des paramètres de la courbe de croissance de Von Bertalanffy. Pour les femelles, ces paramètres sont: CL ∞ = 69,704 mm, TL ∞ = 309,14 mm, W ∞ = 123,01 g, K = 1,062 ans −1 , t 0 = 0,238 ans. Pour les mâles: CL ∞ = 62,658 mm, TL ∞ = 274,18 mm, W ∞ = 115,979 g, K = 1,253 ans −1 , t 0 = 0 ans. Les paramètres de Von Bertalanffy pour les données conjointes sont: CL ∞ = 59,695 mm, t 0 = 0 et K = 1,047 ans −1 et TL ∞ = 246,79 mm, t 0 = 0,410 et K = 0,629 ans −1 et W ∞ = 92,88 g sur la base de TL. La relation générale longueur-poids est: log W = −1,767 + 2,037 log TL (r 2 = 0,842, N = 5505). Les taux de mortalité totale Z et de mortalité naturelle M, combinés pour les deux sexes, sont 2,26 ans −1 et 1,15 ans −1 , respectivement. Le ratio d'exploitation a été estimé à 49%.

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Short CommunicationAge, growth, mortality and sex ratio of sand smelt, Atherina boyeri Risso, 1810 (Pisces: Atherinidae) in the estuary of the Mala Neretva River (middle-eastern Adriatic, Croatia) Summary The present study investigated the age, growth, mortality and morphometry of the sand smelt, Atherina boyeri, in the Mala Neretva River estuary (mid-eastern Adriatic Sea). The study of scale annuli showed that the population is up to 4 years of age. However, most sand smelt are in their first and second year; the numbers of older individuals are very low because they migrate upstream and are heavily fished. The von Bertalanffy parameters for the total sample of sand smelt were found to be L ¥ ¼ 13.5 cm, K ¼ 0.37 year )1 and t 0 ¼ )0.97. Overall total mortality was estimated at 1.81 year )1 , natural mortality was 0.90 year )1 and fishing mortality was 0.91 year )1 .