FISHERY BULLETIN: VOL. 79, NO. 1 



within range of a short, explosive rush — a tactic 

 used during the day by the Hawaiian scorpaenid, 

 Scorpaenopsis cacopsis, which is similarly cryptic 

 (Hobson 1974). Based on gut contents, however, 

 Scorpaena guttata seems to capture most of its 

 prey at night. All seven specimens (140-270 mm 

 SL, jc = 213) collected during the hour before dawn 

 contained prey, many of them fresh. Major items 

 were the crab Podochelia sp. (7 mm), the shrimps 

 Lysmata californica (50 mm) and Spirontocaris sp. 

 (15 mm), and the squid Loligo opalescens (120-190 

 mm), a species that was spawning in the area at 

 the time. One Scorpaena guttata had captured a 

 108 mm Chromis punctipinnis , a species that shel- 

 ters among the rocks at night (see above). In com- 

 parison, of seven individuals (164-237 mm SL, 

 X = 208.3) collected among the rocks during mid- 

 afternoon, the stomachs of four were empty, two 

 contained only well digested octopuses, and one 

 contained recently ingested prey (a crab, Paraxan- 

 thias taylori, 17 mm wide, and a shrimp, Alpheus 

 clamator, 20 mm long). Crabs, shrimps, octopuses. 



squids, and fishes are recognized prey of this 

 species (Limbaugh 1955; Quast 1968). 



Scorpaenidae: Sebastes atrotirens 



The kelp rockfish feeds at night while hovering 

 solitarily in the water column close among the 

 giant kelp plants (Figure 11). It is relatively inac- 

 tive by day — often at rest on rocky substrata or 

 hanging motionless close beneath the kelp canopy. 

 This was the conclusion of Hobson and Chess 

 (1976), who presented details of its diel feeding 

 habits. Of 23 individuals (89-225 mm SL, x = 

 177.5) collected at night, more than 4 h after sun- 

 set, 20 (87%) contained prey, many recently in- 

 gested. Major prey were mysids (Siriella pacifica, 

 4-10 mm, and Acanthomysis sculpta, 4-10 mm), 

 carideans (Hippolyte clarki, 7-14 mm, and Eualus 

 herdmani, 5-10 mm), a gammarid (Batea trans- 

 versa, 3-4 mm), and an isopod {Paracercies 

 crodata, 2-9 mm). 



Figure ll. — in hovering tail-down 

 close beneath the canopy of a kelp 

 forest, this Sebastes atrovirens illus- 

 trates an attitude typical of many noc- 

 turnal predators that hunt in the water 

 column. From this position they may 

 use the relatively light water's surface 

 as a contrasting background against 

 which prey are visible. 



16 



