A Study on Assessing the Feeding, Survival, Fecundity, and Postembryonic Development of Zooplankton Nitocra affinis (Copepoda: Harpacticoida)

Abstract

Copepods are the most copious metazoan subclass on the planet and generally dominate the mesozooplankton, constituting more than 80% of its biomass (Verity and Smetacek 1996). Copepods play a primary role in the marine fish larval diets (Santhanam and Perumal 2012a, b), and on average copepods make up more than 50% of the fish larval gut contents (Stottrup 2000). By forming a vital link between primary and tertiary production, copepods play an important role in the transferring of nutrients and energy in marine ecosystem (Kiorboe 1997; Santhanam et al. 2013). It is well recognized that many marine fish larvae cannot thrive on the traditionally used live feeds like rotifers (Brachionus sp.) and Artemia sp., and this represents a major challenge to the aquaculture industry (Chesney 2007; McKinnon et al. 2003; O’Bryen and Lee 2005), as these species include several high-valued food fishes such as tropical snappers (Lutjanidae.) and groupers (Serranidae and Epinephelinae) and also several marine ornamental species, such as marine Angel fishes (Pomacanthidae) and the seahorse Hippocampus subelongatus (Payne and Rippingale 2001; Vander Lugt and Lenz 2008). On the other hand, copepods have been proven as ultimate food for many cultured marine larvae (Matias-Peralta et al. 2012; Hernandez Molejon and Alvarez-Lajonchere 2003), showing considerable advantages while comparing with rotifers and Artemia (Chen et al. 2006). The advantages of copepods over commonly used hatchery live feeds comprise of their many naupliar and copepodite stages that provide a wide variety of prey sizes for cultured larvae (Chen et al. 2006). Additionally, the nutritional profile of copepods generally matches the needs of marine fish larvae (Stottrup 2000; Evjemo et al. 2003; McKinnon et al. 2003). These advantages make copepods as the potential live feed for the successful larval culture of species that is difficult to be cultured using traditional live feeds (O’Bryen and Lee 2005). Moreover, addition of copepods in diets of previously cultured species could promote their survival, development, and pigmentation (Stottrup 2000; Knuckey et al. 2005; Vander Lugt and Lenz 2008). In spite of these promising features, the use of copepods in aquaculture remains inconsistent (Marcus et al. 2004; Camus and Zeng 2008; Santhanam and Perumal 2012a). This underutilization is mostly accredited to their relative low productivity in intensive culture (O’Bryen and Lee 2005), which could in turn be partly attributed to the lack of research on this field.