Responsible Stock Enhancement

The evolutionary effects captive-bred individuals that can have on wild conspecifics are necessary considerations for stock enhancement programs, but breeding protocols are often developed without the knowledge of realized reproductive behavior. To help fill that gap, parentage was assigned to offspring produced by a freely mating group of 50 white seabass (Atractoscion nobilis), a representative broadcast spawning marine finfish cultured for conservation. Similar to the well-known and closely related red drum (Sciaenops ocellatus), A. nobilis exhibited large variation in reproductive success. More males contributed and contributed more equally than females within and among spawns in a mating system best described as lottery polygyny. Females batch spawned every 1–5 weeks, while males displayed continuous reproductive readiness. Sex-specific mating strategies resulted in multiple successful mate pairings. Understanding a depleted species’ mating system allowed management to more effectively utilize parental genetic variability for culture, but the fitness consequences of long-term stocking can be difficult to address.

Gruenthal, K.M., and M.A. Drawbridge. Toward responsible stock enhancement: broadcast spawning dynamics and adaptive genetic management in white seabass aquaculture. Evol Appl. 5:405-417. 2012.