Initial studies on captive breeding of Chromis limbaughi: Paving the way for its conservation and sustainable production

Limbaugh's damselfish ( Chromis limbaughi ) is, among the risk of extinction categories of the Mexican legislation, under the special protection status; nevertheless, it supports an ornamental fish trade based solely on the capture of wild specimens. Because captive breeding has been postulated as a socially responsible strategy for a sustainable ornamental fish trade, this study aimed at advancing the captive breeding of this species. Fish were sourced from the waters adjacent to San Esteban Island, Gulf of California, Mexico, held in 360-L glass aquaria mimicking the in situ water physicochemical conditions occurring in the wild during the reproductive season, and fed a variety of live and prepared foods. After nine months of rearing, spawns were obtained. C . limbaughi laid 5350 ± 527 (mean ± standard deviation) eggs per spawn, ovoidal in shape, adhered to the substrate by chorionic threads, measuring 862 ± 71.31 μm in length and 619 ± 37.84 μm in width, that hatched within 72.0 ± 7.7 h of incubation with a hatching percentage of 88.2% ± 3.96%. The larvae are altricial, having a relatively small size (2.54 ± 0.17 mm), lacking pigmentation of the optic vesicle and also lacking a functional mouth and anus at hatching. By 2 days post hatch (dph), larvae acquired a blue-gray pigmentation of the eyes and the mouth opened, with a mean mouth gape size of 0.25 ± 0.03 mm. Feeding of larvae with enriched rotifers (3 rotifers/mL) was attempted. Unfortunately, no larvae survived beyond 5dph. In the present investigation, successful maturation of broodstock, spawning, and early larval development of C . limbaughi were achieved for the first time in captivity. Although the advances made in larval rearing were modest, we trust that this work will pave the way for the refining of a larval rearing protocol, contributing to the sustainable production and conservation of this species.