Methods Of Domestic Striped Bass (Morone Saxatilis) Spawning That Do Not Require The Use Of Any Hormone Induction

Nineteen batch spawning trials were conducted using 5th and 6th generation domestic striped bass (Morone saxatilis) to demonstrate the ability of these fish to volitionally spawn in large tanks to produce larvae using only photothermal and salinity conditioning. The findings described are the first report of multiple striped bass successfully batch spawning in captivity without exogenous hormone administration. The results of these trials indicate that an approximately 1:1 ratio of female to male striped bass in a single batch spawning unit is more favorable for production, that a minimum of at least 10 fish of each sex is required to elicit this particular spawning behavior, and that using 25 fish of each sex will yield commercially scalable larval production. This batch spawning method has been employed to effectively and consistently spawn over half of the female striped bass in the National Program for Genetic Improvement and Selective Breeding for the Hybrid Striped Bass Industry (N = 202 of 334 female fish over five years) to produce 44,608,181 swim-up larvae (26.6% hatching rate). Microsatellite genotyping and parentage assignment demonstrates that females will reproduce with between 2 and 18 males and that males will reproduce with between 1 and 6 females. Moreover, the effective broodstock size (N-b) of these batch spawning units is 33 and when accounting for multiple partners and unequal family sizes (N-b(v)) is 28. Lastly, the reported results include the successful spawning of female striped bass staged at and beyond 15 Bayless hours, or those that would have previously been considered ineligible for spawning even with the use of exogenous hormone treatment.