Copepods are considered relevant live feed for fish larval marine aquaculture. They promote fish larval survival and growth rate and reduce deformities when used as food source. The cyclopoid copepod Apocyplops royi are among others used in extensive Taiwanese aquaculture. However, knowledge on its performance in intensive cultures is limited. This study investigates parameters that are relevant prerequisites before initiating intensive tank cultures with A. royi. We found that the biochemical profile of A. royi is promising and relevant when used as live feed with a C:N ratio of 4.7 and a fatty acid ratio (DHA/EPA 3.2 ± 0.7) that fulfil the minimum quantitatively dietary requirement of essential FAs for marine fish larvae and early juveniles. The size range of nauplii (78 - 245 μm) is evaluated to be a feasible size for small mouthed first feeding marine fish larvae. The copepod exhibits similar specific growth rates as other cyclopoids (10% DW d−1). Further, we tested A. royi populations relative composition (nauplii, copepodites, males, females and ovigerous females) as an effect of culture densities and found no change within the test range (300 to 3800 ind. L−1). To evaluate the recruitment into the population we conducted an experiment with densities from a few hundred to 10,000 ind. L−1. We observed no density limitation on the female ovigerous rate = ((ovigerous females) / copepodites + adults) x 100) ~6%) even at very high densities. We demonstrated, that A. royi is a promising candidate for intensive copepod cultures and a relevant live feed for marine larval fish culture.
This study was supported by the Villum Foundation project Acartia Molecular PHysiology – Implementation of novel and fast tools to assess COPepod physiological states (AMPHICOP) No. 8960.
© 2020 Elsevier B.V.