DIEL AND DEPTH VARIATIONS IN THE SEX-SPECIFIC ABUNDANCE, 



SIZE COMPOSITION, AND FOOD HABITS OF 



QUEENFISH, SERIPHUS POLITUS (SCIAENIDAE) 



Edward E. DeMartini/ Larry G. Allen ,2 Robert K. Fountain,^ 



AND Dale Roberts* 



ABSTRACT 



Lampara seine-hauls were taken during day and night over 5-27 m bottom depths off the coast of 

 northern San Diego County, California, from September 1979 to March 1981. These samples were used 

 to characterize the temporal and spatial patterns of the abundances and size and sex compositions of 

 queenfish, Seriphus politus, in an unprotected, coastal environment. Stomach contents of sample 

 queenfish were examined to aid our interpretation of these patterns. 



Adult queenfish of both sexes made diel, onshore, and offshore migrations, but immature fish 

 generally did not. Both immatures and adults occurred in epibenthic, resting schools in shallow areas 

 ( -10 m or less depth, within -1.5 km of shore) during the day. At night, adult fish dispersed (to >3.5 

 km ) offshore. On average, a greater fraction of the adult males emigrated farther offshore at night than 

 adult females. Immature fish remained inshore of 16 m bottom depths (within -2.5 km of shore) at 

 night, with the majority staying inshore of -10 m depth. Regardless of maturity class, larger fish 

 occurred farther offshore at night. 



Stomach contents data confirmed the primarily nocturnal feeding habits of both immature and adult 

 queenfish. Immatures fed primarily on meroplankton and other nearshore prey; however, adults 

 captured offshore had also eaten some nearshore prey. Thus, food habits explain much, but not all of the 

 diel migratory pattern. Immature queenfish may also remain nearshore at night because migration is 

 not worthwhile energetically and because of greater risk of predation offshore. Adults perhaps also 

 migrate offshore at dusk to spawn. 



Numerous physical and biological factors influ- 

 ence the spatial and temporal distribution pat- 

 terns of fishes. In response to such factors, coastal 

 marine fishes often undergo diel shifts in spatial 

 distributions (reviewed by Woodhead 1966; Blax- 

 ter 1970). Examples of horizontal (Hobson 1965, 

 1973; Hobson and Chess 1976; Quinn et al. 1980; 

 Allen and DeMartini 1983) and vertical or water- 

 column (Parrish et al. 1964; Woodhead 1964; 

 Beamish 1966) diel migrations are recognized. 

 Diel horizontal migrations may vary with life 

 stage (e.g., see Hobson and Chess 1973). The type 

 of diel vertical movement also may vary with sea- 

 son and with age and spawning condition of fish 

 (Hickling 1933; Lucas 1936; Brawn 1960; Blaxter 

 and Parrish 1965; Beamish 1966). In other cases, 

 relatively static differences between the depth dis- 

 tributions of juvenile and adult life stages have 



^Marine Science Institute, University of California, Santa 

 Barbara, Calif; present address: Marine Review Committee Re- 

 search Center, 531 Encinitas Boulevard, Suite 114, Encinitas, 

 CA 92024. 



Marine Science Institute, University of California, Santa 

 Barbara, Calif.; present address: Department of Biology, Califor- 

 nia State University, Northridge, CA 91330. 



Manuscript accepted March 1984. 

 FISHERY BULLETIN; VOL. 83, NO. 2, 1985. 



been documented (reviewed by Helfman 1978). 

 Spatial segregation of adult males and females 

 has been commonly observed only in tropical reef 

 fishes (Moyer and Yogo 1982; Clavijo 1983; and 

 others). 



This study describes the manner in which a 

 complex interplay of the factors listed above can 

 determine the temporal and spatial patterns of the 

 distribution of a temperate marine fish. Specifi- 

 cally, we report on diel shifts in the onshore, 

 offshore distribution of queenfish, Seriphus 

 politus, characterize the variation in these diel 

 shifts for immature, adult male, and adult female 

 fish, and relate these shifts to feeding, anti- 

 predator, and breeding functions previously de- 

 scribed. 



The queenfish is a small, schooling sciaenid 

 whose center of geographic distribution lies in the 

 Southern California Bight, south of Point Concep- 

 tion (Miller and Lea 1972). The species contributes 

 significantly to the sport fish catch on piers in 

 southern California (Frey 1971) and provides for- 

 age for several game fishes (Young 1963; Feder et 

 al. 1974). Queenfish form inactive, epibenthic 

 schools nearshore (at — 10 m or less bottom depth) 



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