Aquaculture 2022

February 28 - March 4, 2022

San Diego, California

DIFFERENT EXPERIENCES AT FIRST FEEDING IN JUVENILES FISH PRODUCTION FOR SEVERAL MARINE SPECIES

Ibarra-Castro Leonardo*, Osborne Todd and Martindale Mark

The Whitney Laboratory for Marine Bioscience

 9505 Oceashore Blvd

St. Augustine, Florida USA, 32080

l.ibarracastro@whitney.ufl.edu

 



Life-history evolution has generated many successful reproductive strategies in teleost fishes with different maternal contribution levels (e.g., energy content and quality of yolk and oil globule) to the next generation. T he first feeding is a crucial bottleneck in fish production. It is often associated with ‘mass mortality’ events in  different species raised to date, such as snapper (e.g., Lutjanus guttatus , L. peru , L. argentiventris , L. campechanus , and Ocyurus chrysurus), snooks (Centropomus viridis and C. undecimalis), croakers (Cynoscion nebulosus , Sciaenops ocellatus, and Totoaba macdonaldi) and others species . After hatching, the larvae have to be ready for the transition from endogenous nutr ition to  exogenous food sources . This includes  the development of their  active sensory systems (pigmented eyes, pectoral fins, swimming behavior, jaw gape) as well as physiological-digestive parameters such as liver, pancreatic, intestinal, and stomach enzymes that appear heterochronically between different fishes. Mass mortality events in captive- bred fish are linked to this transition in food source and need to be optimized for every species. For example, snappers (egg size between 600-800 mm and oil droplet not more than 125 mm)  sometimes  have to have their yolk sac entitrely  depleted before  first feeding, while snooks and croakers ( same  egg size  range but with oil droplet between 150 to 250 mm) can feed before yolk sac depletion and accelerate their growth rates. In those fishes, three  critical parameters playing a role at first feeding are the mouth gape (restricting particle size), larval length (restricting swimming capacity and hunting success) and handling. In addition, t he quantity and quality  of  prey  at the appropriate  time  are  important to maintain the  correct  feeding behavior and long-term survival . Our re sults  with more than 20 diferent  marine fish species  rely on the use of healthy enriched rotifers at this stage. Consequently, o ur  different results have shown between 10% to 40% survival in snappers and more than 60% in snooks and croakers. B ased on  those previous experiences,  an innovative red drum  semiautomatic larval rearing system  was designed and  tested at the Whitney Laboratory. With this system, we reached an average of 50 juv/l and more than 60% survival. Hence, we need to keep in mind that at first feeding,  all  larvae can ingest, digest, and assimilate food  that permits them  to  continue  to grow  to  the juvenile stage. In conclusion, it is clear that the reliable production of high-quality juveniles is indispensable for success in new aquaculture species, and  the  first feeding is a crucial step.