FISHERY BULLETIN: VOL. 81, NO. 4 



The estimate for instantaneous total mortality rate 

 (0.17) from the longline fishery in 1978 using all fully 

 recruited ages was undoubtedly too low. E stimates of 

 0.46-0.60 derived from more linear portions of the 

 longline catch curve and the foreign trawl catch 

 curve, respectively, are considered by us to more realis- 

 tic. The difference between the two estimates may be 

 due to a variety of factors, including variation in year- 

 class strength, gear selection, and increased mor- 

 tality rates. The longline estimate may be low if the 

 selectivity for larger sized tilefish noted above 

 applies to fully recruited age groups as well. The 

 foreign trawl estimate may be high because the 

 strong 1973 year class was the first fully recruited 

 year class in 1978, and trawls appear to be biased 

 towards smaller tilefish Alternately, the estimate of 

 total mortality rate from 5 to 8 yr olds from the 

 foreign trawl fishery may more accurately represent 

 recently increased mortality rates than the estimate 

 from 9 to 20 yr olds taken in the longline fishery, 

 because catch curve estimates of Z reflect the history 

 of mortality rates over the lifetime of the year classes 

 sampled (Ricker 1975; Csirke and Caddy 1983). 

 More information on the age structure in different 

 years and for the older members of the tilefish pop- 

 ulation (> 10 yr) is needed to improve the estimates 

 of mortality rate. While our results showed no signifi- 

 cant differences in mortality rates in 1978, the older 

 ages of the females suggest that they may have a 

 lower mortality rate than males. The question of sex- 

 ual differences in mortality should be addressed in 

 greater detail. 



ACKNOWLEDGMENTS 



We are indebted to the late Lionel T Walford for his 

 encouragement and assistance with this research. 

 We could not have completed this research without 

 the aid of numerous other people whom we gratefully 

 acknowledge. S. Katz, M. Horvath, and T Auletta 

 assisted in sampling. D. Long and D. Kolator pro- 

 vided samples from the foreign trawl fishery. B. Free- 

 man provided the 1971-73 data and supervised 

 S.C.T. in the 1974-77 sampling. M. Fahay and P. 

 Berrien provided data on juvenile tilefish. R. Trout 

 provided statistical advice, and G. Shepherd par- 

 ticipated in discussions of analytical approaches. 

 Captain L. Hallock gave us many pounds of free sam- 

 ples. Captains M. Ciell, J. Monfort, R. Moch, and L. 

 Puskas allowed us to sample at sea aboard their 

 vessels. Numerous other captains and personnel 

 from Barnegat Light, N. J., provided invaluable assis- 

 tance. Two anonymous reviewers provided many 

 helpful suggestions. Financial support was provided 



by New Jersey Sea Grant (R/F-2), the New Jersey 

 Agricultural Experiment Station (NJAES Publ. No. 

 D-12409-09-83), and the Center for Coastal and 

 Environmental Studies, Rutgers University. 



LITERATURE CITED 



Able, K. W., C. B. Grimes, R. A. Cooper, and J. Ft. Uzmann. 



1982. Burrow construction and behavior of tilefish, Lopho- 

 latilus chamaeleonticeps, in Hudson Submarine Can- 

 yon. Environ. Biol. Fish. 7(3): 199-205. 



Bagenal, T. B., and F. W. Tesch. 



1978. Age and growth. In T. B. Bagenal(editor), Methodsfor 

 assessment of fish production in fresh waters. LB. P. 

 Handbook No. 3:101-130. Blackwell Scientific Publi- 

 cations, Oxford. 

 Bernard, D. R. 



1981. Multivariate analysis as a means of comparing growth 

 in fish. Caa J. Fish. Aquat. ScL 38:233-236. 

 Berrien, P. L. 



In press. Larval fish distribution in the Mid- Atlantic Bight. 

 Section IV. In M. Grosslein and T. R. Azarovitz ( editors) , 

 Fish distribution. MESA New York Bight Atlas, Mono- 

 graph 15. New York State Sea Grant Institute, Albany. 

 N.Y. 

 BlGELOW. H. B., and W. C. Schroeder. 



1953. Fishes of the Gulf of Maine. U.S. Fish Wildl. Serv., 

 Fish. BulL 53, 577 p. 

 Cooper, R. A., and J. R. Uzmann. 



1977. Ecology of juvenile and adult clawed lobsters. 

 Homarus americanus, Homarus gammarus, and Nephrops 

 norvegicus. In B. F. Phillips and J. S. Cobb (editors). 

 Workshop on lobster and rock lobster ecology and 

 physiology, p. 187-208. Commonwealth Sci. Ind. Res. 

 Organ.. Div. Fish. Oceanogr., Circ. 7. 



Creel, M. 



1981. Search for the golden tile. S. Carolina Wildl. 

 28(5):4-8. 

 CSIRKE, J., AND J. F. CADY. 



1983. Production modeling using mortality rates. Can. J. 

 Fish. Aquat. Sci. 40:43-51. 



DOOLEY, J. K. 



1978. Systematics and biology of the tilefishes(Perciformes: 

 Branchiostegidae and Malacanthidae), with descriptions 

 of two new species. U.S. Dep. Commer., NOAA Tech. 

 Rep. NMFS Circ. 411, 78 p. 



Fahay, M. P., and P. Berrien. 



1981. Preliminary description of larval tilefish, Lopholatilus 

 chamaeleonticeps. Rapp. P.-V. Reun. Cons. Int. Explor. 

 Mer 178:600-602. 

 Grimes, C. B., K. W. Able, and S. C. Turner. 



1980. A preliminary analysis of the tilefish, Lopholatilus 

 chamaeleonticeps, fishery in the Mid-Atlantic Bight. Mar. 

 Fish. Rev. 42(1 1):13-18. 

 Hayashi, Y. 



1976a. Studies on the growth of the red tilefish in the East 

 China Sea - 1. A fundamental consideration for age deter- 

 mination from otoliths. Bull. Jpn. Soc. Sci. Fish. 42:1237- 

 1242. 

 1976b. Studies on the growth of the red tilefish in the East 

 China Sea- II. Estimation of age and growth fromotolith- 

 reading. Bull. Jpn. Soc. Sci. Fish. 42:1243-1249. 

 Helwk;, J. T, and K. A. Council. 



1979. SAS user's guide, 1979 edition. SAS Institute Inc., 



762 



