Assessing Goliath Grouper Reproduction and Age Structure in Spawning Aggregations Off Southeastern Florida
Goliath Grouper Epinephelus itajara is currently listed globally as “critically endangered” and has been protected from both commercial and recreational fishing in U.S. waters since 1990; virtually all of the goliath grouper catch in the U.S. was landed in Florida. Recently there has been interest expressed by fishers to re-open a limited-type of harvest. However, the lack of data on reproduction and age structure of current Goliath Grouper stocks makes it difficult to assess the level of recovery. In the most recent stock assessment, Goliath Grouper were considered to be gonochorists based on an earlier reproductive study from the 1980s. Our current research using biopsies and non-lethal aging of spawning males and females indicated that Goliath Grouper are hermaphroditic and have complete size and age overlap between the sexes (1.2-2.2 m total length; 6-19 years). The age and size distributions of goliath grouper that were female, transitional, male, and “simultaneous hermaphrodites” was at odds for classifying Goliath Grouper as strictly protogynous. Having an accurate picture of the reproductive life style and age structure of Goliath Grouper is critical to providing insight into the vulnerability of the species to fishing pressure in any re-established fishery.