FISHERY BULLETIN: VOL. 84, NO. 4 



PLANKTON COLLECTOR DESIGN 



LID WITH HOLE 

 INNER MESH BAG 



OUTER MESH BAG 



TIMER 



LIGHT 









FLOAT 



^SUBMERSIBLE PUMP 



Y£.s« 



Figure 4.— "Automatic" plankton collector design for feeding giant kelpfish larvae. Plankton were attracted 

 to light on timer after dark. Submersible pump, suspended beneath the float, pumped plankton into large plastic 

 container on dock. Plankton ranging from 100 to 325 ^m were filtered between two mesh bags. Aeration and 

 running seawater kept the plankton alive. 



teased out using either a single human hair or a 

 modified paint brush from which only a few long 

 strands protruded. Gut contents were viewed under 

 a compound microscope and identified, and average 

 lengths and widths of prey items were recorded. 

 At age 2 mo, the kelpfish larvae were moved to 

 containers having 0.3 cm mesh panels and contain- 

 ing artificial plant habitats (see Stepien 1985 and 

 1986). They were subsequently measured bimonth- 

 ly and their development described. Development 

 and feeding of laboratory-reared kelpfish larvae 

 were also compared with 20 field-collected in- 

 dividuals. Kelpfish larvae of various ages and sizes 

 were collected in hand nets while night-lighting from 

 a dock and while scuba diving in kelpbed canopies 

 using a 1 mm mesh handnet. Other kelpfish larvae 

 were examined from bongo net collections made in 

 Santa Monica Bay in 1982. Their development was 

 compared with similar-sized laboratory-reared lar- 

 vae. Gut contents of four early-stage larvae (esti- 

 mated 0-9 d old) were analyzed for food types and 

 sizes, in comparison with laboratory-reared kelp- 

 fish. 



RESULTS 



Spawning 



Giant kelpfish nests were guarded by the male 

 parent, the eggs being interspersed and held by 

 adhesive threads in either red or brown algae (Fig. 

 3B). Seven of the nine nests collected were located 

 in isolated clumps of algae, and all were found be- 

 tween 6 and 12 m deep. Kelpfish nests were most 

 common in the red alga Gelidium nudifrons (6 of 

 9 nests collected) in areas where clumps of taller 

 brown algae covered patches of red algae. Three of 

 the nests were located in brown algae, two in Cys- 

 toseira neglecta, and one in Sargassum muticum. 



The male parent hid in the overlying clump of 

 brown algae, emerging to chase away intruding 

 fishes. Male kelpfish were observed to defend their 

 nests against other kelpfish, sheephead, and rock 

 wrasse. Female kelpfish may spawn several times 

 a year since a female kept in the laboratory laid eggs 

 twice within 3 mo. Gonads of all females examined 

 after spawning were almost entirely spent. Since 



814 



