Meeting Abstract
P3.113 Sunday, Jan. 6 Effects of Extended Incubation on Post-Hatching Growth of Larval California Grunion CARRILLO, A.*; BANSUAN, H.; MIRANDA, A.; DICKSON, K.; Cal. State Univ., Fullerton; Cal. State Univ., Fullerton; Cal. State Univ., Fullerton; Cal. State Univ., Fullerton andresc2@uci.edu
In previous studies of extended embryonic incubation in Leuresthes tenuis, we found that larvae that hatched after extended incubation (at 28 days post-fertilization, dpf) had more skeletal development in the jaws and caudal fin and greater feeding rates than those hatched at 10 dpf (normal incubation), suggesting that the 28-dpf larvae would feed and grow faster after hatching. In this study we measured the same characteristics in grunion incubated at 20°C, hatched at 10 dpf or 28 dpf, and cultured at 20°C for up to 40 days after hatching (dah). We hypothesized that (a) larvae hatched at 10 dpf and grown for 18 dah have greater body length and skeletal development in the jaws and caudal fin than larvae that hatch at 28 dpf (same age post-fertilization), and (b) the post-hatching rate of growth in length and skeletal development of the caudal fin and jaws are greater in L. tenuis hatched at 28 dpf compared to those hatched at 10 dpf. From each of the two incubation groups, five grunion were sampled periodically at 0-40 dah. In each individual, length was measured and skeletal elements were examined in cleared-and-stained fish. Body length was greater and skeletal development was more advanced in larvae hatched at 10 dpf and grown to 18 dah, compared to 28-dpf larvae at hatching. Post-hatching growth in body length and the length of hypural 1 did not differ as a result of extended incubation, whereas the number of dentary teeth and caudal skeletal elements differed only at 0-4 dah. Thus, we conclude that the previously measured increases in feeding rate and skeletal morphology at hatching do not result in higher post-hatching growth, and that grunion that extend incubation do not reach the size of those that hatch earlier, at least within 40 days after hatching.
