THE REPRODUCTIVE BIOLOGY OF TILEFISH, 



LOPHOLATILUS CHAMAELEONTICEPS GOODE AND BEAN, FROM 



THE UNITED STATES MID-ATLANTIC BIGHT, AND 



THE EFFECTS OF FISHING ON THE BREEDING SYSTEM 



Churchill B. Grimes/ Charles F. Idelberger,^ Kenneth W. Able,^ 



AND Stephen C. Turner* 



ABSTRACT 



To investigate the reproductive biology of tilefish, LopholatAlus chamaeleonticeps Goode and Bean, we 

 sampled the commercial longline fishery from 1978 to 1982. Results suggested that tilefish are frac- 

 tional spawners from March to November with a spawning peak from May to September. Estimates 

 of fecundity ranged from about 195 x 10^ to 10 x 10*^ (for 53 cm FL, 2.1 kg and 91 cm FL, 13 kg 

 females), but only 60-85% of the ovarian eggs appeared to have been released by the end of the spawn- 

 ing season. 



Tilefish are apparently gonochoristic however, some adult males had slight amounts of ovarian tissue 

 within the testicular mass. Sex ratios were skewed in favor of males at larger sizes; however, both sexes 

 were present at most ages. All juveniles and unsexed fish (<400 mm FL) appeared to be female (i.e., 

 gonad cell structure consisted of oogonia and previtellogenic oocytes), suggesting that some tilefish may 

 undergo prematurational sex reversal, or that early gonad development involves an all female appear- 

 ing stage. 



Tilefish may have a complex breeding system that is behaviorally mediated. Both sexes are func- 

 tionally mature at ca. 50 cm FL and 5 years, but some males appear to delay participation in spawning 

 for 2-3 years and 10-15 cm in additional length. Tilefish are sexually dimorphic, with males attaining 

 larger sizes and developing conspicuously enlarged predordal adipose flaps (an apparent indicator of male 

 breeding status) at 65-70 cm FL (6-7 years), when males begin to participate in spawning (i.e., develop 

 large testes), not when they are functionally mature (i.e., producing sperm). 



The rapidly expanding fishery from 1978 to 1982, which reduced population density by one-half to 

 two-thirds, may have altered the breeding system by causing males to spawn at smaller sizes (10 cm) 

 and younger ages (2-2.5 years) in 1982 than in 1978. 



Tilefish, Lopholatilus chamaeleonticeps (Branchio- 

 stegidae), is a demersal gonochoristic species found 

 along the outer continental shelf from Nova Scotia 

 south to Surinam (Dooley 1978; Markle et al. 1980). 

 Within the Mid-Atlantic Bight (continental shelf 

 between Cape Cod, MA and Cape Hatteras, NC), 

 they inhabit a narrow zone of relatively warm tem- 

 peratures (9°-14°C) in about 80-240 m depths. Fol- 

 lowing a brief period as pelagic larvae (Fahay and 

 Berrien 1981; Berrien 1982), juveniles settle to the 

 bottom. Adults are sexually dimorphic, males hav- 

 ing larger adipose flaps ( = predorsal crest of Dooley 



'Southeast Fisheries Center Panama City Laboratory, National 

 Marine Fisheries Service, NOAA, 3500 Delwood Beach Road, 

 Panama City, FL 32407. 



^Florida Marine Research Institute, 100 8th Ave. S.E., St. 

 Petersburg, FL 33701. 



^Rutgers University, Marine Field Station, Tuckerton, NJ 08087. 



■•Southeast Fisheries Center Miami Laboratory, National Marine 

 Fisheries Service, NOAA, 75 Virginia Beach Drive, Miami, FL 

 33149. 



1978) than females (Katz et al. 1983). Growth in both 

 sexes is about 10 cm per year for the first four years, 

 then it slows, but more so in females than males 

 (Turner et al. 1983). Maximum size of females is 

 about 100 cm FL and 112 cm FL in males, and max- 

 imum ages are 35 and 26 years, respectively (Turner 

 et al. 1983). 



Both juveniles and adults select sedimentary sub- 

 strata, and seek shelter in a variety of habitats. 

 Grossman et al. (1985) found a strong correlation 

 between sediment composition and tilefish occur- 

 rence. Juveniles and adults occupy highly conta- 

 geously distributed vertical burrows, the primary 

 habitat, in Pleistocene clay substrata (Able et al. 

 1982; Grimes et al. 1986). Adults also inhabit hori- 

 zontal excavations in more vertically oriented clay 

 sediments of submarine canyon walls called "pueblo 

 habitats" (Cooper and Uzmann 1977; Warme et al. 

 1977; Grimes et al. 1986), and scour depressions 

 under and around glacial erratic boulders (Valen- 



Manuscript accepted April 1988. 



fishery BULLETIN: VOL. 86, NO. 4, 1988. 



745 



