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Abstract: Light can have significant impacts on larval growth and survival of many marine fish species. Here, we study the effect of photoperiod on larvae from captive populations of two marine finfish species, California yellowtail (CYT; Seriola lalandi) and white seabass (WSB; Atractoscion nobilis). Two photoperiod treatments were tested: 12h light and 12h dark (12-L), and 24h light and 0h dark (24-L). CYT larvae were significantly heavier (240±16μg dry weight) in the 24-L treatment group than the 12-L group (155±25μg dry weight) at 10dph. Similarly, WSB were significantly heavier (685±77μg dry weight) in the 24-L treatment group than the 12-L group (455±44μg dry weight) at 18dph. CYT larvae also had significantly greater survival (16.6±6.2%) in the 24-L treatment over the 12-L conditions (7.6±4.9%). In contrast, WSB larvae showed no significant difference in survival between treatments. Food consumption was significantly greater in the 24-L treatment for both species up until 6dph, after which time no difference was observed. Swim bladder inflation rates were not significantly affected by the photoperiod treatments. These results indicate that photoperiod is a significant factor in early larval performance for both CYT and WSB, although it is unknown if continuous light becomes detrimental as larvae develop. [Copyright &y& Elsevier]

Abstract: Environmental parameters, such as light intensity and turbidity, have been shown to significantly influence the growth and survival of cultured larval finfish. Here, we study three light intensities (low: 360lx; medium: 1675lx; and high: 14,850lx) and two turbidity conditions (with and without green water) to determine optimum growth and survival for California yellowtail (Seriola lalandi) larvae. The study lasted from 2 thru 16days post hatch (dph). The high light intensity, green water treatment produced the largest larvae (865±165μg dry weight; 7.01±0.07mm notochord length), had the highest survival rate (9.2±3.1%), and had the highest incidence of swimbladder inflation (68.8±3.1%) among all treatments in this study. The low and medium light intensity, clear water treatments produced the smallest larvae (183±60μg dry weight; 5.58±0.07mm notochord length) and the lowest survival rate (0–0.10%). These results indicate that light intensity and turbidity are significant factors that affect growth and survival of Seriola lalandi larvae up to 16dph. [Copyright &y& Elsevier]