Feeding rates and prey preference in Octopus americanus paralarvae fed with different prey densities and types, Artemia , copepods, and zoeae

Nutrition and the lack of an established protocol for the larviculture of Octopus are some of the bottlenecks for the development of Octopus aquaculture. This study aims to start filling in these knowledge gaps by obtaining daily feeding rates (FR) of Octopus americanus paralarvae at different ages by testing different live prey types (Artemia nauplii, Acartia lilljeborgii copepods, and Callinectes sapidus zoeae) and densities (20, 40, 60, 80, 120, and 160 prey L−1). In addition, prey preference was assessed by exposing paralarvae to these prey types simultaneously. The dry weight (DW) of the prey was obtained and used to estimate the daily DW ingestion rate of paralarvae. Experiments were performed with 1- and 8–9-day-old paralarvae. The FRs recorded for different prey densities and the effect of different prey types on prey preference were analyzed through one-way ANOVA. The FRs recorded were quite different among the preys tested. The highest mean FRs for hatchlings was 26.2±6.9 zoeae paralarva−1 day−1 and for 8-day-old paralarvae was 63–69 Artemia nauplii paralarva−1 day−1. Therefore, the following prey densities are recommended for the larviculture of paralarvae up to 10 days of age: 80 copepods L−1, 160 Artemia nauplii L−1, and 80 zoeae L−1. Hatchlings showed a significant preference for zoeae, and Artemia nauplii and zoeae were significantly more preyed by 8-day-old paralarvae. Our results demonstrated that increasing prey density increases FR and predation by paralarvae, and zoeae were by far the preferred prey of hatchlings.