Growth rates of larval and juvenile bigeye scad Selar crumenophthalmus in captivity

Aaron Welch,Zach Daugherty,Sasa Miralao,Bruno Sardenberg,John Stieglitz,Dan Benetti,Ronald Hoenig,Dan Farkas

doi:10.1186/2193-1801-2-634

Abstract

Growth rates of larval and juvenile bigeye scad Selar crumenophthalmus reared in captivity were studied. The results are presented, discussed, and compared to wild S. crumenophthalmus and other pelagic fish. S. crumenophthalmus are a small pelagic carangid fish of circumtropical distribution. Larvae were reared in a modified mesocosm system and sampled daily for growth. Larvae grew to a mean size of 4.74 cm (Standard Length) and 1.30 g by 45 days post hatch (dph). Larval length-at-age was best described by the exponential equation Y = 1.966e0.0704t. For juvenile growth trials, 1940 fish were stocked into four 2.5 m3 cylindro-conical tanks at two different densities (262 fish m-3 and 120 fish m-3) and reared from 45 dph to subadult stage. Fish were sampled daily for growth. No statistically significant differences in growth or survival were detected between tanks. Mean length and weight at 141 dph was 13.24 cm (Total Length) and 25.20 g. Juvenile length-at-age was best described by the Von Bertalanffy Growth Model equation Lt = 27.75(1 – e-0.03(t-1.57)). Weight-at-age was best described by a linear equation Wt = 1.7313x + 12.4662. The exponent of the length-weight equation was 3.14. In addition to providing the first published description of larviculture and juvenile growout techniques for S. crumenophthalmus, this study contains the first published data on this species’ larval growth and directly confirms estimates of S. crumenophthalmus juvenile growth done by other researchers using indirect techniques such as otolith daily growth increment and frequency distribution analysis.

Highlights

Bigeye scad Selar crumenophthalmus (Bloch) are a small pelagic, schooling fish of circum-tropical distribution (e.g. Dalzell and Penaflor 1989; Clarke and Privitera 1995; Mohammed and Rennie 2003; Hendiarti et al 2005; Roos et al 2007)
Larval growth Larval S. crumenophthalmus grew to a mean weight of 1.30 g and 4.74 cm Standard Length (Ls) by 45 dph
Metamorphosis was complete for all fish by 45 dph, when the juveniles were transferred to growout tanks

Summary

Introduction

Bigeye scad Selar crumenophthalmus (Bloch) are a small pelagic, schooling fish of circum-tropical distribution (e.g. Dalzell and Penaflor 1989; Clarke and Privitera 1995; Mohammed and Rennie 2003; Hendiarti et al 2005; Roos et al 2007). Wild S. crumenophthalmus exhibit rapid growth rates, reaching a fork length (Lf ) of approximately 20 to 25 cm in one year (Dalzell and Penaflor 1989; Roos et al 2007) and have been observed with a Lf of more 28 cm (Ralston and Williams 1988). They are partial spawners, and have been estimated to release 92,000 eggs per spawn (Clarke and Privitera 1995). We compare length-weight data for both wild and captive juvenile S. crumenophthalmus and describe larviculture and juvenile growout techniques for the species

Materials and methods

Results

Discussion