STEPIEN: LIFE HISTORY AND DEVELOPMENT OF KELPFISH 



all eggs in the nests examined were in similar stages 

 of development, it is likely that each nest contains 

 the eggs of a single female. After spawning (the 

 behavior sequence of which is described in Coyer 

 1982), the male kelpfish chases away the female 

 parent, as was observed in the laboratory on three 

 separate occasions. In one case, the male's repeated 

 pursuits resulted in the female jumping out of the 

 aquarium. 



Eggs occurred in two different colors, red and 

 brown, which microscopic examination showed was 

 due to color of the yolk. All eggs in a given nest were 

 either red or brown and remained that color 

 throughout development. Nest and egg color did not 

 always match. Brown eggs were found in four nests 

 of red algae and two nests of brown algae, while red 

 eggs were found in two nests of red algae and one 

 nest of brown algae. 



Fertilized eggs laid in the laboratory developed 

 poorly and few of them hatched, apparently due to 

 abnormal dispersal in the algal nests by the females. 

 In all three cases of laboratory spawnings, eggs 

 were laid in clumps rather than being well-spaced 

 throughout the algae, as observed in field-collected 

 nests. Freshly laid nests were collected in the field 

 on three occasions from pairs that had just com- 

 pleted spawning. Two of the three spawning females 

 were brown colormorphs and one was a red morph, 

 but all three showed the barred melanin pattern. All 

 nine field-collected male parents were brown color- 

 morphs exhibiting the characteristic male nuptial 

 striped melanin pattern (Coyer 1982; Stepien 1985, 

 1986). 



Egg Development and Hatching 



Eggs from freshly laid nests hatched in 12-17 d 

 at 18°C, the largest number hatching in 13 d. Eggs 

 averaged 1.4 mm in diameter and nests contained 

 an average of 700 eggs, ranging from 400 to 1,200 

 eggs. An estimated 800 of the 1,200 eggs hatched 

 from the most successful laboratory incubation. 

 Nests that were rotated vigorously and kept well- 

 aerated produced the most successful hatchings. 



The sequence of egg development is summarized 

 in Table 1 and photographs of the developing eggs 

 are shown in Figure 3. Hatching occurred from day 

 14 through day 15. Hatching took about 20 min, the 

 larvae emerging head-first from the egg membrane. 



Early Larval Development 

 (Prenotochord Flexion) 



Giant kelpfish larvae can be distinguished from 



other southern California clinid larvae by their large 

 numbers of myomeres, averaging 55-59. Newly 

 hatched larvae had large yolk sacs and well- 

 developed mouths, guts, melanophores, and fin folds 

 and averaged 6.2 mm TL (Fig. 5A). Larvae floated 

 upside-down, yolk up, for the first 24-36 h after 

 hatching. They swam with wriggling movements, 

 lasting about 30 s, interspersed with longer periods 

 of inactivity, lasting up to several minutes. 



Yolk sacs were present 36-48 h after hatching. 

 Two- day-old larvae averaged 7.0 mm TL and swam 

 strongly upright, showing positive attraction to light 

 and concentrating near the white mesh areas of the 

 containers. After 4 d, the larvae were less positive- 

 ly photo tactic, concentrating towards the bottom of 

 the containers. Mean sizes and a summary of the 

 sequence of larval development are listed in Table 

 2. Illustrations of larvae are found in Figure 5. 



Later Larval Development 

 (Postnotochord Flexion) 



Flexion of the notochord had begun by 7-9 d and 

 an average size of 8.5 mm (ranging from 7.6 to 8.9 

 mm, N = 12). Field-collected giant kelpfish larvae 

 also showed the beginnings of notochord flexion at 

 a similar size (7.4-9.3 mm, N = 5). Size at notochord 

 flexion is smaller than that reported by Matarese 

 et al. (1984) for other clinid larvae. 



Two-week-old giant kelpfish larvae began swim- 

 ming in organized schools, which also were observed 

 in situ in giant kelp canopies. Other researchers have 

 also noted this phenomenon (Feder et al. 1974), 

 which was not observed in giant kelpfish past the 

 age of 2 mo in both the laboratory and the field. By 

 3 wk, the schooling larvae became progressively 

 more difficult to catch with dip nets, exhibiting well- 



Table 1.— Summary of kelpfish egg developmental stages. 



Developmental features 



well-developed blastodisc, beginnings of epiboly 



head fold apparent, neural tube forming 



embryo wrapped 180° around egg's circumfer- 

 ence; notochord, somites, eyes, and lenses 

 visible 



embryo wrapped 240° around egg's circumfer- 

 ence, myomeres well-developed, lenses of eyes 

 pigmented, heart beating 95 times per minute 



yolk shrunk to 1/2 size of egg; embryo curled 1.5 

 times around egg; mouth differentiated; gut, 

 liver, and inner ear developing 



otoliths and pectoral and dorsal fin folds visible, 

 vigorous tail movements, heart beats 90 to 100 

 times per minute 



hatching at 18°C, larva exits head-first, hatching 

 takes about 20 min 



12d 



14 d 



815 



