Comparative Reproductive Biology of Hawaiian Parrotfishes: Input for Management Regulations and Stock Assessment

Parrotfishes (Labridae, Scarinae) rank among the most economically important reef fishes in Hawaii and throughout the tropical Pacific. Many of these protogynous (female-first, sex-changing) fishes are also major habitat engineers of great ecological significance. Yet few data exist on their reproductive dynamics or vital rates in Hawaii or elsewhere. A single minimum body length (12 inches fork length) for the take of parrotfish (“uhu”) is presently in effect in the State of Hawaii even though the multiple species contributing to the fishery likely differ in their fundamental life histories. For this reason we assembled comprehensive data on size-specific gonadal development, using specimens collected during 2005-2007 and 2012-2014 on Oahu, and estimated median body sizes at sexual maturity and at sex change for the five major (of seven total) species of parrotfishes in the local fishery. Median sizes at maturity (from immature to adult female) differed greatly among the five major species, and sizes at sex change (from adult female to secondary male) were proportional to sizes at female maturity and estimated maximum body lengths of the respective species. Changes in minimum size regulations are suggested for the two largest, fishery-dominant species, along with further research into age, growth, and longevity.