arenaria possessing the life history statistics 

 given above, 1 out of about 790,000 eggs pro- 

 duced during the lifetime of an individual must 

 survive to ensure continuance of the population. 



However, variable recruitment and high post- 

 larval mortality tend to be the general rule 

 among temperate and boreal marine inverte- 

 brates, especially the bivalves. At the Jones 

 River in Gloucester, the tidal flat received a 

 heavy set of young Mya arenaria in 1973 (Brous- 

 seau 1978a, b). Based on crude estimates of stock 

 density, age-specific fecundity, and the density 

 of the resultant spatfall, the settlement rate was 

 0.0498%, or about 34 times larger than the cal- 

 culated r., eq . During the two subsequent years, 

 on the other hand, this site received only a lim- 

 ited spatfall, which, coupled with high postlarval 

 mortality, resulted in settlement rates of 0.0%. 

 Under such fluctuating conditions, therefore, 

 the settlement history of a population takes on 

 added significance. 



In addition to being of theoretical interest, 

 determination of the equilibrium settlement 

 rate for a commercially important species may 

 be of value in its harvesting management as well. 

 Although the impact of repeated exploitation is 

 difficult to assess given the uncertainties of en- 

 vironmental conditions, continued harvesting on 

 tidal flats receiving annual settlement rates 

 below equilibrium may prove to be extremely 

 harmful to the resident population. 



Literature Cited 



Brousseau, D. J. 



1978a. Spawning cycle, fecundity, and recruitment in a 

 population of soft-shell clam, Mya arenaria, from Cape 

 Ann, Massachusetts. Fish. Bull., U.S. 76:155-166. 

 1978b. Population dynamics of the soft-shellclam Mya 

 arenaria. Mar. Biol. (Berl.) 50:63-71. 

 Gledhill, C. 



1980. The influence of established infauna on recruit- 

 ment of the soft-shell clam, Mya arenaria L. M.S. 

 Thesis, Univ. Massachusetts, Amherst, 40 p. 

 Leslie, P. H. 



1945. On the use of matrices in certain population mathe- 

 matics. Biometrika 33:183-212. 

 1948. Some further notes on the use of matrices in pop- 

 ulation mathematics. Biometrika 35:213-245. 

 Muus, K. 



1973. Settling, growth and mortalityof young bivalves in 

 the Oresund. Ophelia 12:79-116. 

 Thorson, G. 



1950. Reproductive and larval ecology of marine bottom 



invertebrates. Biol. Rev. (Camb.) 25:1-45. 

 1966. Some factors influencing the recruitment and 

 establishment of marine benthic communities. Neth. 

 J. Sea Res. 3:267-293. 



Van Winkle, W., D. L. DeAngelis, and S. R. Blum. 



1978. A density-dependent function for fishing mortality 

 rate and a method of determining elements of a Leslie 

 matrix with density-dependent parameters. Trans. 

 Am. Fish. Soc. 107:395-401. 

 Vaughan, D. S., and S. B. Saila. 



1976. A method for determining mortality rates using 

 the Leslie matrix. Trans. Am. Fish. Soc. 105:380-383. 



Diane J. Brousseau 



Department of Biology 

 Fairfield University 

 Fairfield, CT 061,30 



Department of Mathematics 

 Fairfield University 

 Fairfield, CT 061,30 



Jenny A. Baglivo 

 George E. Lang, Jr. 



GROWTH OF JUVENILE RED SNAPPER 



LUTJANUS CAMPECHANUS, IN 



THE NORTHWESTERN GULF OF MEXICO 1 



The red snapper, Lutjanus campechanus, has re- 

 ceived considerable attention in the past due to 

 its importance as a commercial and sport fish in 

 the Gulf of Mexico. Most published material 

 deals with the fishery and is summarized in 

 Carpenter (1965). Few major papers have dealt 

 with the natural history of red snapper. 



Moseley (1965) reported on growth, reproduc- 

 tion, and food habits of red snapper taken by 

 trawl and handline off the Texas coast. He deter- 

 mined age and growth rate from scales by 

 assuming that growth checks were produced 

 during the spawning season. Bradley and Bryan 



(1975) also sampled red snapper along the 

 middle Texas coast with trawl and hook and line. 

 They were unable to distinguish age classes by 

 length frequencies and attributed that to an ex- 

 tended spawning season. Futch and Bruger 



(1976) used otolith readings to determine age and 

 growth of red snapper off the coast of Florida. 



This paper presents new information on 

 growth of young snapper and relates that infor- 

 mation to their occurrence on an artificial reef. 



'University of Texas Marine Science Contribution No. 519. 



644 



FISHERY BULLETIN: VOL. 80. NO. 3. 1982. 



