Age, growth, and mortality of the karamote shrimp, Melicertus kerathurus (Forskål, 1775), in the east Ionian Sea (western Greece)

Abstract

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%.

Studies on the allometric growth of the caramote prawn Melicertus kerathurus (Decapoda, Penaeidae) in Western Greece (E. Mediterranean)

“…The M. kerathurus population in the Amvrakikos Gulf belongs to the 0 and 1 year classes only (maximum 1+) and only a very small number of individuals were found belonging to 2 and 2+ classes (CONIDES et al, 2006). Earlier studies in the Amvrakikos Gulf from 1980 to 1984 Medit.…”

“…Despite the fact that the major aspects of the biology of this species in the Amvrakikos Gulf have recently been published (CONIDES et al, 2006;2008, KEVREKIDES & THESSALOU-LE-GAKI, 2006KARANI et al, 2005), this is the first attempt to study the morphometric profile of both sexes of M. kerathurus individuals on a seasonal basis, and to discuss any possible significant differences, comparing the results with similar studies obtained in the Mediterranean basin. Moreover, this is the first study concerning the appendix masculina of the caramote prawn.…”

Recent expansion of Northeast Atlantic and Mediterranean populations of Melicertus (Penaeus) kerathurus (Crustacea: Decapoda)

“…This local differentiation of a new matriline probably indicates a long period of isolation from the other samples. Moreover, overfishing or environmental degradation [34] should also be taken into consideration. Even when the Amvrakikos sample was removed, comparisons between the Mediterranean and the Atlantic regions and among the Mediterranean samples still revealed a significant level of differentiation; the value obtained (U st = 0.044, P \ 0.03) agrees with the figures observed in other marine invertebrate species ( [16] and references therein) with similar distributions, even though there are some contradictory results.…”

Population dynamics of Melicertus kerathurus (Decapoda: Penaeidae) in Thermaikos Gulf (N. Aegean Sea)

“…Rodríguez, 1977Rodríguez, , 1986Wadie and Abdel Razek, 1985;Ben Meriem, 1993, 2004Lumare and Scordella, 2001;Can et al, 2004;BelloOlusoji et al, 2005;Kevrekidis, 2009;Akyol and Cehyan, 2009). However, intense exploitation rates since the 1970s have resulted in a significant decrease in stock abundance, reflected in declining annual landings in Spain, Italy and Amvrakikos Gulf (Ionian Sea, Greece) (Rodríguez, 1977;Scordella and Lumare, 2001;Conides et al, 2006). Moreover, the Aswan damn construction in Egypt has led to a drastic reduction of M. kerathurus production, while small sized Eritrean species represent the bulk of penaeid prawn catches in the area of Alexandria (Wadie and Abdel Razek, 1985).…”