An Experimental Study of the Effect of Temperature on the Incubation Time, Development, and Growth of Pacific Sardine Embryos and Larvae

Incubation time, development, and growth of individual Pacific sardine eggs and larvae were studied in relation to environmental temperatures between 11 and 21 C. Time from spawning to hatching decreased with increasing temperature from approximately 140 hr at 11 C to 34 hr at 21 C. Maximum growth occurred in yolk sac larvae between 16 and 17 C before shrinking due to starvation. A functional jaw and pigmented eyes failed to develop in sardine larvae at temperatures below 13 C. In contrast, the northern anchovy, a clupeoid inhabiting much of the same ecological range as the sardine, hatches sooner and develops normally at these low temperatures. A comparison of incubation times deduced from field studies with these experimental results showed a close correspondence at all but extreme temperatures.