The Inter-American Tropical Tuna Commission (IATTC) has been conducting research on the early life history and biology of tropical tunas at the Achotines Laboratory in the Republic of Panama since 1986. Spawning from a population of y ellowfin t una (YFT) has taken place almost daily in the Laboratory's land-based tank since 1996. Eggs and larvae collected from the broodstock tank are used to conduct biological and physical experiments aimed at gathering ecological information on early life history stages.
The near-daily spawning of yellowfin at the Achotines Laboratory represents the only sustained spawning of yellowfin in captivity in the world. Water temperature is the most potent influence on timing and occurrence of spawning in our tank population . Broodstock fish exhibit the ability to increase their daily egg production in response to increases in daily food ration. Overall spawning dynamics of the yellowfin broodstock population will be described.
Pre-recruit research on yellowfin at the Achotines Laboratory has focused on growth and survival dynamics of larvae (the first 3 weeks), but in recent years the research focus has expanded to the early-juvenile stages (1-6 months). Growth rates of larval yellowfin (3-16 mm SL) have been estimated in the laboratory and in situ . Growth rates have been estimated for all transformation and early-juvenile individuals reared in land-based tanks or a sea cage; the early-juveniles have ranged from 1.6-28.0 cm in length and up to 158 days after hatch.
The studies of growth during the first 6 months have strong application to tuna aquaculture. In 2015, in collaboration with Kindai University, the first transfer worldwide of yellowfin juveniles from landbased tanks to a sea cage was successfully completed. The overall growth dynamics of larval and early-juvenile stages will be described, and juvenile rearing studies planned for 2020 will be summarized.