INVESTIGADORES
BONEL Nicolas
congresos y reuniones científicas
Título:
Preliminary study of the population structure and allometry of the introduced shrimp Palaemon macrodactylus in the Salado River, Argentina
Autor/es:
NICOLÁS BONEL; PILAR ALDA; SERGIO R. MARTORELLI
Lugar:
Nashville, Tennessee
Reunión:
Conferencia; Aquaculture 2013; 2013
Institución organizadora:
The American Fisheries Society, the World Aquaculture Society and the National Shellfisheries Association
Resumen:
The invasive oriental shrimp Palaemon macrodactylus was first reported in Argentina in 2006 and has expanded its distributional range along the Argentina Atlantic coast. The knowledge of their ecology and biology, however, is still inchoate. The main goal of this study was to analyze the size structure and allometry of P. macrodactylus from the Salado River, Argentina. We collected a total of 113 individuals in March and December 2011 and in May 2012 from the lower basin of the Salado River. The sex was determined by the presence of the appendix masculine and we classified females as nonovigerous and ovigerous based on the presence of eggs. We measured the carapace length (CL) and weigh all specimens (the eggs of ovigerous females were remove before weigh). The size distribution was constructed using CL measurements. We estimated the allometric relation-ship of wet weight (WW) as function of CL. The size at 50% sexual maturity (CLm) of ovigerous females was calculated using a logistic equation. Ovigerous females showed larger CL (20.7±2.8 mm) than nonovigerous females (15.2±4.3 mm) and males (12.7±3.1 mm); males were shorter than both female stages (P = 0.0001, Fig. 1). Allometric regressions indicated a negative allometry for males (b=2.50), a positive allometry for nonovigerous females (b=3.53), and a slightly negative allometry for ovigerous females (b=2.94) (Table 1). The CLm was 15.96 mm and 80% of the total females (n=84) had greater CL than the estimated CLm (Fig. 2). This is the first study that estimates the CLm for females of the invasive shrimp P. macrodactylus in the Neotropical region. Our results indicated that females are significantly larger than males and would support sexual dimorphism. The change in the allometry from positive (nonovigerous females) to slightly negative (ovigerous females) would be related to allocation of energy to reproduction rather than growth in ovigerous females.