Seasonal changes in gonad maturity, proximate and fatty acid composition of Limbaugh’s damselfish, Chromis limbaughi Greenfield & Woods, 1980 (Pisces: Pomacentridae)

Abstract

Limbaugh?s damselfish, Chromis limbaughi Greenfield & Woods, 1980, is endemic to the Gulf of California, and one of the five most exploited species for the aquarium trade in this region. C. limbaughi is a gonochoristic, gregarious and territorial species without sexual dimorphism that inhabits rocky, sheltered areas. Development of captive breeding techniques for this species would not only ensure a continued supply of fish for the commercial trade, but perhaps more importantly, it would also alleviate fishing pressure and support stock enhancement. Thus, as a first step towards achieving these goals, in this work, we investigated some aspects of the reproductive biology of C. limbaughi. Seasonal fish samplings, with a total of eighty-nine fish caught in one year, were carried out at San Esteban Island, Gulf of California, Mexico. The reproductive season of C. limbaughi extends, at least, from May to September. A new maximum standard length of 10.5 cm is reported for this species. The estimated size at first sexual maturity was 7.90 cm for males and 7.59 cm for females. For both male and female gonads, the major constituent fatty acids were palmitic acid, stearic acid, oleic acid, docosahexaenoic acid, eicosapentaenoic acid and arachidonic acid. The water-quality conditions under which maturation of C. limbaughi took place were measured, and should prove useful for the management of broodstock in captivity.

Arachidonic acid matters

“…In tongue sole, a medium level of dietary ARA (5.14% TFA) upregulated the expression of follicle-stimulating hormone receptor (fshr), steroidogenic acute regulatory protein (star), cholesterol side-chain cleavage enzyme (p450ssc), 3β-and 17 β-hydroxysteroid dehydrogenase (3β-hsd, and 17β-hsd) in immature females, but downregulated the gene expression of fshr, 3βhsd, 17β-hsd, and aromatase in mature females. 125 This was consistent with a decrease of ARA content in ovaries during sexual development, 125 which was also observed in other species, such as silver pomfret (Pampus argenteus), 123 Limbaugh's damselfish (Chromis limbaughi) 160 and bluefin tuna (Thunnus thynnus thynnus). 161 In Atlantic cod females, plasma concentrations of vitellogenin, estradiol-17β and testosterone, and transcript levels of key genes, P450aromatase (cyp19a1a) and 20bhydroxy steroid dehydrogenase (20bhsd/cbr1), were affected by dietary ARA (0.5%-4.0% TFA), and interestingly, these effects were also dependent on gonadal development stage.…”

Sex difference in fatty acid composition of six marine teleosts

“…Other FAs also showed sex difference, although not as significant as the FA mentioned earlier. In addition, the D sex and TOP DFA may be dynamic dependent on gonad developmental stage (Nogueira et al ., 2017; Pacetti et al ., 2013), sampling season (González‐Félix et al ., 2019; Uysal et al ., 2006) and lipid type (Chatzifotisa et al ., 2004; Hiratsuka et al ., 2004). The precise mechanisms involved the sex differences in fish FA composition need to be elucidated by future studies.…”