STATUS OF THE TILEFISH, LOPHOLATILUS CHAMAELEONTICEPS, 



FISHERY OFF SOUTH CAROLINA AND GEORGIA AND 



RECOMMENDATIONS FOR MANAGEMENT 



Joseph E. Hightower' and Gary D. Grossman^ 



ABSTRACT 



We used a sex- and age-structured model and CPUE data from commercial and research vessels to assess 

 the current status of the tilefish, Lopholutilus chamaeleont-keps, substock off South Carolina and Georgia. 

 Based on commercial CPUE data and assumed natural mortality (M) rates of 0.10-0.25, we estimated 

 that adult popiJation density prior to fishing ranged from 603 to 950 per km" and stock biomass ranged 

 from 1.130 to 1,570 tonnes (t). Our estimates of the recommended fishing mortality rate ranged from 

 0.10 {M = 0.10) to 0.48 (M = 0.25), resulting in sustainable yields of 40 (A/ = 0.10) to 82 t (M = 0.25) 

 per year. We obtained higher estimates of virgin population density (883-1,710 per km") when research 

 CPUE data were used. Sustained yield estimates also were higher, ranging from 55 (M = 0.10) to 148 

 t{U = 0.25) per year. Average estimates of recommended yield from commercial and research CPUE 

 data were 58 and 95 1, respectively. Observed yields m the developing fishery exceeded 100 1 in 1981-84 

 and in 1986; however, current observations indicate that fishing effort has declined to a low level in 

 response to reduced catches. Based on the assumption that commercial CPUE data better reflect popula- 

 tion trends, we recommend that the annual harvest not exceed about 50 t, which should result in a stock 

 biomass of about 400-800 t. Apparent limitations on sustainable yield from the fishery probably can be 

 attributed to the long lifespan, slow growth rate, and sedentary natiire of tilefish. 



The tilefish, Lofholatilus chamaeleonticeps, is a 

 large demersal species found along the outer con- 

 tinental shelf of North America from Nova Scotia 

 to Key West, FL, along the Gulf coast to Campeche 

 Bank, and off South America from Venezuela to 

 Surinam (Freeman and Turner 1977). Tilefish are 

 long-lived and have relatively slow growth rates 

 (Harris and Grossman 1985). They are most com- 

 mon at depths of 100-400 m and water tempera- 

 tures of about 9°-14°C (Freeman and Turner 1977). 

 Abundance is greatest in areas where substrates are 

 suitable for burrow construction (Able et al. 1982; 

 Grossman et al. 1985) or afford other shelter such 

 as scour depressions around boulders (Valentine et 

 al. 1980) or rubble piles (Low and Ulrich 1983). 



Katz et al. (1983) described two genetically distinct 

 tilefish stocks through use of morphometric and elec- 

 trophoretic data: one composed of tilefish from the 

 Middle Atlantic Bight (MAB), and one composed of 

 tilefish from the South Atlantic Bight (SAB) and 

 Gulf of Mexico. Larval transport from the Gulf of 



'School of Forest Resources, University of Georgia, Athens, GA 

 30602; present address: Southwest Fisheries Center Tiburon 

 Laboratory, National Marine Fisheries Service, NOAA, 3150 

 Paradise Drive, Tiburon, CA 94920. 



^School of Forest Resources, University of Georgia, Athens, GA 

 30602. 



Manuscript accepted October 1988. 

 Fishery Bulletin, U.S. 87:177-188. 



Mexico to the SAB may be responsible for similar- 

 ities in electrophoretic results for these two areas 

 (Katz et al. 1983). Katz et al, (1983) suggested, how- 

 ever, that it may be necessary to manage these sub- 

 stocks separately because of their wide geographic 

 separation. If true, this should be done with the 

 understanding that Gulf of Mexico populations may 

 serve as a source of recruits to SAB populations 

 (Katz et al. 1983). 



Tilefish have been harvested commercially in the 

 MAB since 1915, with annual landings ranging from 

 <1 tonne (t) to 4,500 t (Turner et al. 1983). Land- 

 ings from the SAB and Gulf of Mexico were small 

 prior to 1980 (Low et al. 1983). A limited number 

 of tilefish were caught incidentally in the deepwater 

 grouper fishery off South Carolina (Low and Ulrich 

 1982). Recreational catches were small because of 

 the depth at which tilefish occur (Low and Ulrich 

 1982). Commercial fisheries have since developed 

 in both the SAB and Gulf of Mexico, due in part to 

 an interest in diversification within the shrimp in- 

 dustry (Low et al. 1983). 



For the segment of the SAB tilefish fishery oper- 

 ating off South Carolina and Georgia, increased 

 fishing effort has resulted in a substantial increase 

 in tilefish landings since 1978 (Table 1). In addition, 

 a considerable nimiber of tilefish caught off Georgia 



177 



