Editing Grouper (section)

== Reproduction ==
Groupers are mostly monandric [[protogynous hermaphrodite]]s, i.e., they mature only as females and can change sex after sexual maturity.<ref name="Erisman2009">Erisman, B. E., M. T. Craig, and P. A. Hastings. 2009. A phylogenetic test of the size-advantage model: Evolutionary changes in mating behavior influence the loss of sex change in a fish lineage. American Naturalist 174:83-99.</ref><ref name ="DeMartini">DeMartini, E. E., A. R. Everson and R. S. Nichols. 2011. Estimates of body sizes at maturation and sex change and the endemic Hawaiian grouper's spawning seasonality and sex ratio (''Hyporthodus queries'', f. Epinephelidae). Fishery Bulletin 109:123-134.</ref> Some species of groupers grow about a kilogram per year and are generally adolescents until they reach three kilograms when they become female. The largest males often control harems containing three to 15 females.<ref name="Erisman2009" /><ref name="Sadovy">Sadovy, Y. and P. L. Colin. 1995. Sexual development and sexuality in the Nassau grouper. Journal of Fish Biology 46:961-976.</ref> Groupers often pair spawn, which enables large males to competitively exclude smaller males from reproducing.<ref name="Erisman2009" /><ref name="Allsop">Allsop, D. J. and S. A. West. 2003. Constant relative age and size at sex change for sequentially hermaphroditic fish. Journal of Evolutionary Biology 16:921-929.</ref><ref name="Munoz">Munoz, R. C. and R. R. Warner. 2003. A new version of the size-advantage hypothesis for sex change: Incorporating sperm competition and size-fecundity skew. American Naturalist 161:749-761.</ref><ref name="Kuwamura">Kuwamura, T. 2004. Sex change in fishes: Its process and evolutionary mechanism. Zoological Science 21:1248-1248.</ref> As such, if a small female grouper were to change sex before it could control a harem as a male, its fitness would decrease.<ref name="Allsop" /><ref name="Munoz" /><ref name="Kuwamura" /> If no male is available, the largest female that can increase fitness by changing sex will do so.<ref name="Munoz" />

However, some groupers are [[gonochoristic]].<ref name="Erisman2009" /> Gonochorism, or a reproductive strategy with two distinct sexes, has evolved independently in groupers at least five times.<ref name="Erisman2009" /> The evolution of gonochorism is linked to group spawning high amounts of habitat cover.<ref name="Erisman2009" /><ref name="Munoz" /><ref name="Erisman2008">Erisman, B. E., J. A. Rosales-Cassian and P. A. Hastings. 2008. There is evidence of gonochorism in a grouper, ''Mycteroperca rosacea'', from the Gulf of California, Mexico. Environmental Biology of Fishes 82:23-33.</ref> Both group spawning and habitat cover increase the likelihood of a smaller male reproducing in the presence of large males. The fitness of male groupers in environments where competitive exclusion of smaller males is impossible is correlated with sperm production and thus [[testicle]] size.<ref name="Sadovy" /><ref name=" Munoz" /><ref name="Molloy">Molloy, P. P., N. B. Goodwin, I. M. Cote, J. D. Reynolds, and M. J. G. Gage. 2007. Sperm competition and sex change: A comparative analysis across fishes. Evolution 61:640-652.</ref> Gonochoristic groupers have larger testes than protogynous groupers (10% of body mass compared to 1% of body mass), indicating the evolution of gonochorism increased male grouper fitness in environments where large males were unable to competitively exclude small males from reproducing.<ref name="Sadovy" />