Reproduction, early development, and larval rearing strategies for two sponge-dwelling neon gobies, Elacatinus lori and E.colini

Abstract

A major goal of the aquaculture industry is to reduce collection pressure on wild populations by developing captive breeding techniques for marine ornamental species, particularly coral reef fishes. The objective of this study was to develop a rearing protocol for two recently described species of neon gobies that are endemic to the Mesoamerican Barrier Reef: 1) Elacatinus lori; and 2) Elacatinus colini. First, the current study describes the reproductive behavior and larval development of both species. Second, it evaluates the effects of different rotifer and Artemia densities on the survival and growth of E. lori and E. colini larvae. Third, it compares the survival and growth of E. colini larvae fed wild plankton to those fed a combination of rotifers and Artemia. Once acclimated, pairs of E. lori began spawning in 53.2 ± 12.4 d (mean ± sd), while pairs of E. colini took only 12.2 ± 10.3 d. E. lori produced more embryos per clutch (1009 ± 477) than E. colini (168 ± 83). E. lori larvae hatched 8.18 ± 0.4 days after initial observation with a notochord length of 3.67 ± 0.2 mm. In comparison, E. colini larvae hatched 6.8 ± 0.4 days after initial observation with a notochord length of 3.51 ± 2.3 mm. Both species settled as early as 28 days post hatch at 9–9.5 mm standard length, following the fusion of the pelvic fins to form a pelvic disc. During rotifer density trials, from 0 to 6 days post hatch, there was no significant difference in survival or standard length between treatments fed 10, 15 or 20 rotifers ml^− 1 for either species. During Artemia density trials, from 6 to 14 days post hatch, control treatments fed solely on 15 rotifers ml^− 1 had significantly higher survival than treatments that were fed rotifers in combination with 3, 6 or 9 Artemia ml^− 1. Finally, E. colini larvae that were fed wild plankton had significantly higher survival and growth than those fed with a combination of 15 rotifers ml^− 1 and 3 Artemia ml^− 1. The results of this study suggest that Artemia nauplii are not a suitable prey for E. lori or E. colini larvae. Our results demonstrate the feasibility of rearing E. lori and E. colini to settlement, and suggest that 10–20 rotifers ml^− 1 and wild plankton provide a viable starting point for optimizing the survival and growth of Elacatinus spp. larvae.