BROODSTOCK COLLECTION AND CAPTIVE SPAWNING PROTOCOLS FOR ALMACO JACK Seriola rivoliana
Almaco jack Seriola rivoliana have been identified as an important marine finfish for aquaculture development in the Gulf of Mexico Fishery Management Plan due to their fast growth, high market value, and adaptability to intensive culture conditions. These fish are also known as bar jacks, longfin yellowtail, almaco amberjack, and Kona Kampachi. The main bottlenecks associated with commercial aquaculture production include: 1) susceptibility to parasitic and bacterial pathogens; 2) an inconsistent supply of juveniles resulting from poor spawn quality and low hatchery survival. Therefore, the goals of the project included designing protocols to maintain broodstock health; identifying photo-thermal conditions needed for the maturation and spawning of high quality eggs and larvae.
In early 2017, a total of 42 adult almaco jacks were captured in the Gulf of Mexico approximately 150 km offshore and transported to Mote Aquaculture Research Park (MAP) located in Sarasota, Florida. All fish were vented and placed in square totes (working volume 760 L-1) which were continuously supplied with new water from the boat's live well and pure oxygen was supplemented during the transport back to shore. A live hauler was used to transport the fish from Madeira Beach, FL to MAP. Upon arrival, fish were divided into two populations and a health management plan was initiated. During the quarantine period, the fish underwent a hypo-salinity treatment where salinities were decreased from 35 to 15 ppt over the course of 7 days. Approximately 45 days later, the salinity was increased to 35 ppt and an evaluation was conducted to confirm the successful removal of any external parasites. Fish are currently being fed a fresh frozen diet (70% thread herring and 30% squid) and maintained in two separate indoor recirculating tank systems (volume 28 m3) equipped with photo-thermal control, bio-filter, solids filter, and UV sterilization. Fish began spawning daily (volitionally) without hormone induction following the initial photo-thermal conditioning regime (26°C and 13 hr of light). To date, a total of 2.8 million eggs have been collected with a 68% mean fertilization rate. Progress regarding the development of captive maturation, spawning, and broodstock health management protocols will be discussed.