Lion's paw scallop (Nodipecten subnodosus, Sowerby 1835) aquaculture in Bahia Magdalena, Mexico: effects of population density and season on juvenile growth and mortality

Abstract

This study examined the e¡ects of density and growing season on growth and survival of juvenile lion's paw scallops (Nodipecten subnodosus) in Estero San Buto, a mangrove channel in Bah|¤ a Magdalena, Mexico. Scallops were kept in plastic mesh bags in oyster trays at three population densities (500, 1000 and 2000 organisms per tray, or low medium and high density respectively) over a period of 2 months from October to December 2001and from February to April 2002. Growth (shell height increment) was measured every 7^12 days and mortality was evaluated at the end of the experiment (dead shell count). Overall growth was fast (0.24^0.38 mm day À1 ) in comparison with other pectinids. Signi¢cant di¡erences were found for both, density and season, with faster growth occurring at lower densities and during the fall season when the water temperature was higher. Mortality was low (0.5^3.0% 60 day À1 ) except for the high-density treatment in the fall (44% 60 day À1 ). Crowding together with high water temperatures and increased metabolic oxygen demand of the scallops and possibly competition for food were the probable reasons for this high mortality. Overall, mortality was lower in the spring, when temperatures were lower, O 2 values were higher and food was more abundant.Independent, two-tailed t-tests were used for statistical comparisons, P-values are shown in the last column. SD, standard deviation; Chl, chlorophyll.Aquaculture Research, 2005, 36, 505^512 Growth and mortality of juvenile lion's paw scallops V Koch et al.

Evaluation of different shallow water culture methods for the scallop Nodipecten subnodosus using biologic and economic modeling

“…Most scallops contain relatively low amounts of glycogen in the adductor muscle (Sundet and Vahl, 1981;Epp et al, 1988;Racotta et al, 2003), and so provide little relief to anaerobic requirements, especially during reproductive periods when carbohydrate stores are particularly low. However, immature Lion's Paw spat (3-30 mm) cultured at the same location grew better in fall under warm water conditions (Koch et al, 2005), indicating that non-reproductive juveniles may have a higher temperature tolerance than mature adults.…”

“…1. Map of the Bahía Magdalena complex and study area (Koch et al, 2005). mm of average shell height) was chosen.…”

“…All six treatments were modeled (3 methods × 2 densities). Before grow-out conditions were simulated, seed growth was described linearly using a growth rate of 0.35 mm·day − 1 as was reported by Koch et al (2005) for seed cultured under fall conditions (start date = October 8th) at a seed density of 1000/tray in suspended modules. The following linear function was used to describe seed growth (3-40 mm):…”

“…A mortality constant (Z year ) of 0.1744 (adapted from Koch et al, 2005) was applied to Eq. (2) for seed survival.…”

CRECIMIENTO Y SUPERVIVENCIA DE JUVENILES DE Argopecten purpuratus EN SISTEMAS DE FONDO Y SUSPENDIDO EN LA ZONA DE CASMA, PERÚ

“…Estos resultados coinciden con aquellos realizados en esta especie y en otras especies de pectinidos de otras regiones tanto sistema suspendido como en sistema de fondo (Cáceres-Martínez et al, 1986;Ysla et al, 1987;Parsons & Dadswell, 1992;Cote et al, 1993;Freites et al, 1995Cisneros & Arguelles, 1996;Acosta et al, 2000;Freites et al, 2001;Lodeiros et al, 2002;Mendo et al, 2002;Cano, 2004;Koch et al, 2005). Al respecto MacDonald & Ward, (1994) sostienen que densidades muy altas pueden reducir el eutrofismo en el agua a través del alimento y por consiguiente una competencia intra e ínter especifica.…”