DeMARTINI ET AL: DISTRIBUTION PATTERNS OF QUEENFISH 



ADULT FEMALE QUEENFISH 



SIZE FREQUENCIES 



NIGHT 5-lOM DEPTH N=642 NIGHT 11-16M DEPTH N=350 



LiJ 

 O 



q: 



O 

 (J 



o 



>- 



o 



UJ 



o 

 ir 



UJ 

 Q. 



o 



X 



en 



g 



2 



10- 



0-- 



5- 



10- 



15- 



c 



Figure 3. — Relative length-frequency distributions of (A) immature, (B) adult male, and (C) adult female queenfish 

 caught during the night in the shallow versus middepth blocks (see Figure 1 caption for details). (Data for the deep depth 

 block were too few to evaluate independently. ) 



m depths nearshore during the day (also see Dis- 

 cussion and Conclusions). 



In order to further aid our interpretation of the 

 function of the observed nocturnal offshore move- 

 ments, we subdivided our diel catch data into three 

 periods of year: 1) February-July (the onshore, 

 breeding season; see DeMartini and Fountain 

 1981); 2) August-October (the onshore, non- 

 breeding season); and 3) November-January 

 (the offshore, nonbreeding season). Analyses were 

 restricted to size-frequency data for queenfish 

 seined at shallow and middepths during the two 

 periods of onshore distribution, as scant data on 

 the size composition of adults were available for 

 the offshore season. During both breeding and 

 nonbreeding onshore periods, queenfish seined at 

 shallow depths were larger during the day versus 

 at night, and fish caught at night were consis- 

 tently larger in middepth versus shallow collec- 

 tions (Table 3). Thus the year-round patterns 

 illustrated by Figures 2 and 3 also basically 

 characterize both breeding and nonbreeding 

 periods of onshore distribution. 



Food Habits 



The food habits of immature, adult male, and 

 adult female queenfish were evaluated for day and 

 night collections made in the shallow- and mid- 

 depth blocks during the onshore, breeding and 

 onshore, nonbreeding periods of year (Stomachs of 

 fish from the deep depth block were not examined. ) 

 The purpose of these comparisons was to help 

 interpret the relative importance of the feeding 

 and breeding functions of diel offshore movements. 

 We hypothesized that immature fish might remain 

 onshore at night to feed on meroplanktonic (noc- 

 turnally active) demersal crustaceans and other 

 prey more abundant at shallow depths. We further 

 expected that adults emigrated offshore to spawn 

 (DeMartini and Fountain 1981) and thereafter fed 

 on relatimely larger prey that were more preva- 

 lent farther offshore. In general, immature 

 queenfish fed on smaller prey than adult males, 

 and adult males, being smaller than adult 

 females, fed on generally smaller prey than 

 females (Table 4). Contrary to expectations, adult 



177 



