Publication Date




Embargo Period


Degree Type


Degree Name

Master of Science (MS)


Marine Ecosystems and Society (Marine)

Date of Defense


First Committee Member

Daniel Benetti

Second Committee Member

Marjorie Oleksiak

Third Committee Member

Tillmann Benfey


The current population growth trend and increases in seafood consumption rates necessitate increases in marine aquaculture production. In the search for the ideal marine species to fill this demand, Cobia (Rachycentron canadum) offers a suitable candidate for the seafood staples. This is the result of high commercial value, rapid growth rates and success of mass seed production. The primary cost driver in fish production is feed, and efforts to optimize feed conversion ratios therefore are constantly being made. Among these are methods to capture sex-specific growth improvements through monosex culture, which is relevant for cobia aquaculture because of increased growth seen in females over males. The presented work provides the data required to effectively execute a monosex (all-female) culture program in cobia. Research focused on identifying the labile period, during which a fish’s sex is deterministically plastic. Identifying a method to determine the genetic sex of individuals was also investigated. This is necessary to isolate the desired genetic sex for controlled crosses. Lastly, the effectiveness of exogenous hormones for manipulating sex ratios was also investigated. The indirect method of monosex production is one in which the fish intended for consumption are never exposed to hormones directly. This is accomplished by using specific broodstock and avoids any stigma associated with exogenous hormones while still having control over sex.



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