Optimizing Feeding Strategies for Yellowtail Jack at Winter Water Temperatures

Abstract

Recent research has primarily focused on optimizing diet formulations and feeding regimes for Yellowtail Jack Seriola lalandi (known as Yellowtail Kingfish in Australia) during warm, optimal water temperatures. Further research on these aspects of production is needed during cool, suboptimal winter water temperatures. In this 84-d study, the growth performance and feed efficiency of Yellowtail Jack (1.44 kg) fed a commercially formulated diet at seven feed rates, ranging from 0.1% of body weight (BW) 1 d/week to apparent satiation 6 d/week, at cool water temperatures (11.5–16°C) were investigated. Yellowtail Jack fed to apparent satiation 6 d/week exhibited significantly higher growth rates and significantly better feed conversion ratios than fish fed at lower feed rates. The maintenance requirement for fish fed the formulated diet was 0.2047% BW/d (digestible energy and protein maintenance requirements are 30.1 kJ and 0.82 g · kg fish−1 · d−1, respectively). To provide nutrition slightly above this rate and ensure growth, fish may be fed to apparent satiation 2 d/week. Feeding fish below this maintenance rate during winter is not recommended, as the study fish lost weight. Underfeeding may also manifest itself in nutrient deficiency symptoms and health problems. We recommend that fish be fed the formulated diet to apparent satiation 6 d/weekduring winter. We also recommend further research to validate the current results under commercial conditions.