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cfiSHERIES
CJWEARCH
ELSEVIER Fisheries Research 26 ( 1996) 125-13 7

Growth, mortality and yield-per-recruit of the

deep-water shrimp Aristeus antennatus

( Crustacea-Aristeidae) of the Strait of Sicily
( Mediterranean Sea)

Sergio Ragonese *·a, Marco L. Bianchini b
"Istituto di Tecnologia della Pesca e del Pescato, CNR, Via L. Vaccara, 61, Maz.ara del Vallo, ltaly
"P.F. RA/SA, CNR, Rome, ltaly
Accepted 21 February 1995

Abstract

The MIX and Compleat ELEFAN methods were used to analyse length-frequency distributions of
females of the deep-water shrimp Arìsteus antennatus in arder to estimate growth, mortality and yield-
per-recruit. Length data were gathered in four seasonal experimental trawl surveys made in the Strait
of Sicily ( Mediterranean Sea). Up to four annua! cohorts were distinguishable. Modallengths w ere
integrated and the parameters of the von Bertalanffy growth function estimated by a weighted non-
linear regression, yielding an asymptotic carapace length of 69.1 mm and an annua! Brody' s coefficient
K=0.532. with a location parameter 1 0 =0 (line through the origin). The consistency of these
estimates was evaluated by comparison with the corresponding parameters obtained applying ELE-
FAN-1 and producing a confidence interval by bootstrap resampling; this last procedure revealed the
presence of two possible solutions corresponding to a 'slow' and a 'fast' growth hypothesis. The
growth estimates derived from the moda! progression analysis in any case fall inside the confidence
ellipse of the bivariate plot of the asymptotic lengths and growth coefficients derived from the
bootstrapped data sets. The total annua! mortality was estimated as Z = l .l, following Heincke' s
approximation; two values of annua! natura! mortality, M = 0.5 and M h= 0.8, were used afterwards.
1
As a negative allometric length-weight relationship (h< 3) does exist, the incomplete beta function
was applied t o compute the yield-per-recruit values. Analysis of the Y l R curves suggests that the
current Y l R ca n be improved by a moderate increase, from l to 1.5 years, in the age of fìrst capture;
this could be ohtained by increasing the mesh size of the cod-end from the present 18 mm to 28 mm.
without any economie loss, even short term.

Ken\'Ords: Ariste/l.\' lllltenn{/fus: Red shrimps: Mediterranean Sea: Yie1d-per-recruit: Growth-fish

* Corresponding author: Te!. + 39 923 948723, Fax. + 39 923 906634.

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