Reproduccion De Peces

Aquaculture 265 (2007) 176 – 186 www.elsevier.com/locate/aqua-online

The effect of fish stocking density on the growth of California halibut (Paralichthys californicus) juveniles
German E. Merino a,b, , Raul H. Piedrahita c , Douglas E. Conklin d
a b

Departamento de Acuicultura, Facultad de Ciencias del Mar, Universidad Catolica del Norte, Larrondo 1281, Coquimbo, Chile Centro de EstudiosAvanzados en Zonas Aridas (CEAZA), Unidad Regional de Desarrollo Científico & Tecnológico (CONICYT), Colina El Pino s/n, La Serena, Chile c Biological and Agricultural Engineering Department, University of California, Davis, California, USA d Department of Animal Science, University of California, Davis, California, USA Received 27 July 2006; received in revised form 12 January 2007; accepted 17January 2007

Abstract The ability to raise California halibut (Paralichthys californicus) at a relatively high density, thus maximizing culture area usage, is of particular importance for future commercial operations. The effect of stocking densities between 100 and 300% of coverage area (PCA) on growth of juvenile (11.6 g) fish was tested in experiments that lasted 8 to 10 weeks. Theexperiments were carried out in a recirculation system in small rectangular tanks and raceways with water depths under 6 cm. It was found that maximum fish growth was achieved for fish stocked initially at 100% PCA. The results showed that California halibut can be grown in shallow tanks and raceways at a relatively high stocking density without significantly compromising growth rate and survivability. ©2007 Elsevier B.V. All rights reserved.
Keywords: Stocking density; California halibut; Paralichthys californicus; Surface area; Culture density; Flatfish

1. Introduction The ability to raise fish at a relatively high density, thus maximizing usage of the fish production infrastructure, is of importance to commercial aquaculture especially in recirculation systems. Both positive and negativerelationships between stocking density and growth have been reported and the pattern of this interaction appears to be species specific. The importance of stocking density on fish growth has been reported for several species, such us
Corresponding author. Departamento de Acuicultura, Facultad de Ciencias del Mar, Universidad Catolica del Norte, Larrondo 1281, Coquimbo, Chile. Tel.: +56 51 209 767;fax: +56 51 209 764. E-mail address: gmerino@ucn.cl (G.E. Merino). 0044-8486/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.aquaculture.2007.01.028

rainbow trout (Oncorhynchus mykiss) (Trzebioatowski et al., 1981), Nile tilapia (Oreochromis niloticus) (CarroAnzalota and McGuinty, 1986), hamoor (Epinephelus tauvina) (Abdullah et al., 1987), Arctic charr (Salvelinusalpinus) (Christiansen et al., 1992), African catfish (Clarias gariepinus) (Kaiser et al., 1995), gilthead sea bream (Sparus aurata) (Canario et al., 1998), and lake sturgeon (Acipenser fulvescens) (Fajfer et al., 1999). There are a few studies on the effect of stocking densities on the growth of flatfish: turbot (Scophthalmus maximus) (Martinez-Tapia and Fernandez-Pato, 1991; Irwin et al., 1999,2003), olive flounder (Paralichthys olivaceus) (Jeon et al., 1993), Atlantic halibut (Hyppoglossus hyppoglossus) (Bjørnsson, 1994), and summer flounder (Paralichthys dentatus) (King et al., 1998).

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Flatfish species are bottom dwelling fish and to enhance growth and survival it has been recommended to provide an environment with ahigh bottom area to water volume ratio (Cripps and Poxton, 1992; Kaiser et al., 1995; Øiestad, 1999; Labatut and Olivares, 2004). Stocking density for flatfish may be expressed either as biomass per unit of bottom area or as a percentage of coverage area (PCA = percent ratio of total fish ventral area to total tank bottom area). Commercial land-based facilities usually stock their fish at densities...