582 



Abstract— Life-history dynamics of pin- 

 fish (Lagodon rhomboides) were exam- 

 ined from data derived from random- 

 station surveys conducted in Tampa 

 Bay and adjacent Gulf of Mexico waters 

 during 1993-97. In addition, patterns 

 in spatial distribution and abundance 

 in Gulf of Mexico waters were inves- 

 tigated. Ages determined from whole 

 otoliths ranged from to 7 years, and 

 von Bertalanffy growth models for 

 males and females were not signifi- 

 cantly different. Von Bertalanffy growth 

 model parameters were L„=219.9 mm 

 SL, k =0.33/yr, and ^,| =-1.10 years for 

 all fish combined. High gonadosomatic 

 indices during October-December indi- 

 cated that some spawning may occur 

 in Tampa Bay. Estimated lengths at 

 50'7f maturity were 132 mm SL for 

 males and 131 mm SL for females. Total 

 instantaneous mortality rates derived 

 from the Chapman-Robson estimator 

 ranged from 0.88 to 1.08/yr, and natural 

 mortality was estimated to be 0.78/vr. 

 In Gulf of Mexico waters, pinfish catch 

 rates declined with increasing depth, 

 and most pinfish were caught in <17 m 

 of water Length distributions showed 

 that pinfish segregate by size with 

 increasing depth. 



Age, growth, mortality, and distribution of 

 pinfish (Lagodon rhomboides) in Tampa Bay 

 and adjacent Gulf of Mexico waters 



Gary A. Nelson 



Ronda Fish and Wildlife Conservation Commission 



Flonda Manne Research Institute 



100 Eighth Avenue SE 



St. Petersburg, Flonda 33701 



Present address: Massachusetts Division of Manne Fisheries 

 Annisquam River Marine Fishenes Station 

 30 Emerson Avenue 

 Gloucester, Massachusetts 01930 



E mail address Gary.NelsoniSistatema us 



Manuscript accepted 15 February 2002. 

 Fish. Bull. 100:,582-592 (2002). 



The pinfish (Lagodon rhomboides) is 

 an ecologically important sparid that 

 inhabits estuarine and offshore waters 

 of the United States from Massachu- 

 setts to Texas (Darcy, 1985). Young- 

 of-the-year pinfish are predators on 

 a range of invertebrates in estuaries, 

 often to the degree that entire assem- 

 blages of macrobenthic fauna are 

 affected (Young et al., 1976; Young 

 and Young, 1977; Nelson. 1978), They 

 also consume seagrasses during their 

 estuarine phase, which makes them an 

 important link between primary and 

 secondary production (Stoner, 1982; 

 Weinstein et al., 1982; Montgomery 

 and Targett, 1992). Both young-of-the- 

 year and adult pinfish are prey for 

 other fishes (Gunter, 1945; Darnell, 

 1958; Carr and Adams, 1973; Seaman 

 and Collins, 1983) and are used as bait 

 for many recreationally and commer- 

 cially important species. 



Despite their ecological and economi- 

 cal importance, the population biol- 

 ogy and dynamics of pinfish in Florida 

 have not been adequately examined. 

 Most knowledge about growth (Reid, 

 1954; Caldwell, 1957; Hellier, 1962; 

 Nelson, 1998), distribution and migra- 

 tion (Caldwell, 1957; Hansen, 1970; 

 Nelson, 1998), and mortality (Nelson, 

 1998) comes froin studies of young-of- 

 the year pinfish in estuaries. The only 

 information available on older indi- 

 viduals comes from estuarine studies 

 that describe size and age at spawning 

 (Caldwell, 1957; Hansen, 1970), gross 

 fecundity (Caldwell, 1957), and lon- 

 gevity and size at age (Hansen, 1970). 



However, that information may contain 

 biases because sampling did not extend 

 into offshore waters where larger, and 

 presumably older, pinfish are thought 

 to occur, particularly during cooler 

 months (Darcy, 1985). 



In this study, age, growth, mortality, 

 and maturation of pinfish were evalu- 

 ated by studying data from multigear 

 fisheries-independent surveys conduct- 

 ed in Tampa Bay, Florida, and in off- 

 shore waters off west-central Flonda. 

 In addition, patterns in abundance and 

 spatial distribution of pinfish in the 

 Gulf of Mexico were examined. 



Methods 



Biology 



Pinfish for aging, maturity, and mor- 

 tality analyses {n=711) were collected 

 opportunistically from fall 1993 to 

 spring 1997 during multiple fisheries 

 surveys conducted in Tampa Bay and 

 offshore Gulf waters by the Florida 

 Marine Research Institute (Fig. 1). 

 Pinfish from Tampa Bay were collected 

 primarily during multigear seasonal 

 (spring and fall) and monthly fisher- 

 ies-independent surveys designed to 

 estimate relative abundance of small 

 estuarine fishes and evaluate life-his- 

 tories parameters of large estuarine 

 fishes (Table 1). During the surveys, 

 sites were chosen by randomly selecting 

 1" latitude x 1" longitude microgrids, 

 representing the site to be sampled, 

 within randomly selected 1' latitude x 



