442 



AbStraCt.-We examined 528 bone- 

 fish ranging from 21 to 702 mm FL col- 

 lected in South Florida waters from 

 1989 to 1995. Ages of 451 bonefish rang- 

 ing from 228 to 702 mm FL were esti- 

 mated from thin-sectioned otoliths 

 (sagittae). Examination of OTC-marked 

 otoliths from five fish held in a pond in 

 the Florida Keys for periods ranging 

 from 14 to 29 months suggested that a 

 single annulus was formed each year. 

 Marginal-increment analysis also 

 showed that a single annulus was 

 formed each year during March-June. 

 Bonefish reach a maximum age of at 

 least 19 years. Growth of the bonefish 

 in our study was rapid until an age of 

 about six years and then slowed con- 

 siderably. The von Bertalanffy growth 

 equation for females was FL=680.9( 1- 



e (-0.279(A« f+ 934)1) and for males was 



FZ,=670.7< i^'-o 242(^*i sis.., The over . 

 all growth models for males and fe- 

 males were significantly different, but 

 estimates of individual growth param- 

 eters L w , K, and / were not. Predicted 

 lengths of females were greater than 

 those of males for all ages greater than 

 1 year. Catch-curve estimates of instan- 

 taneous rates of total mortality (Z) were 

 0.21 (95% confidence interval 0.167- 

 0.303) for females and 0.25 (95% confi- 

 dence interval 0.098-0.406) for males. 

 Empirically derived estimates of natu- 

 ral mortality were similar to total mor- 

 tality estimates, suggesting that fish- 

 ing mortality is low. 



Age, growth, and mortality of 

 bonefish, Albula vulpes, from the 

 waters of the Florida Keys 



Roy E. Crabtree 

 Christopher W. Harnden 

 Derke Snodgrass 

 Connie Stevens 



Florida Marine Research Institute. Department of Environmental Protection, 

 100 Eighth Avenue SE, St. Petersburg, Florida 33701-5095 



Manuscript accepted 19 January 1996. 

 Fisherv Bulletin 94:442-451 (1996). 



Bonefish, Albula vulpes, are mod- 

 erate-size elopomorph fish that fre- 

 quent coastal and inshore waters of 

 tropical seas worldwide. In the 

 western Atlantic, bonefish regularly 

 occur in the Florida Keys, the 

 Bahama Islands, and throughout 

 the Caribbean Sea (Hildebrand, 

 1963). In many areas of the species' 

 range, including the waters off the 

 Florida Keys, bonefish are the ba- 

 sis of economically important rec- 

 reational fisheries. Bonefish are re- 

 nowned by anglers for their wari- 

 ness and fighting abilities and are 

 often caught in water as shallow as 

 0.3 m. In the Florida Keys, fishing 

 for bonefish is a year-round activ- 

 ity and provides an important 

 source of income for professional 

 fishing guides. The commercial sale 

 of bonefish in Florida is prohibited; 

 the limits placed upon the recre- 

 ational fishery for bonefish are a 

 bag limit of one fish per angler per 

 day and a minimum fish size of 457 

 mm total length. Bonefish are not 

 considered a food fish in Florida, and 

 most bonefish caught are released. 



Bonefish life history has not been 

 adequately described. Bruger ( 1974 ) 

 described the age and growth of 

 bonefish from an examination of 

 scales of 205 bonefish from South 

 Florida waters. He estimated the 

 age of the oldest bonefish in his 

 study to be 12 years and suggested 

 that greater ages may be attained. 



His attempt to validate annulus for- 

 mation on scales using the marginal- 

 increment technique was inconclu- 

 sive, perhaps because annulus for- 

 mation in scales often occurs over a 

 prolonged period and because an- 

 nuli are often closely spaced in older 

 fish, making validation of scale-de- 

 rived ages by the marginal-incre- 

 ment technique difficult (Lowerre- 

 Barbieri et al., 1994). In addition, 

 Bruger's sample sizes for many 

 months were small. 



Since Bruger's work, studies on 

 a variety of species have shown that 

 scales are not reliable for ageing 

 long-lived fishes and that scale-de- 

 rived age estimates are typically 

 lower than validated estimates de- 

 rived from sectioned otoliths ( Beam- 

 ish and McFarlane, 1983; Cassel- 

 man, 1983; Lowerre-Barbieri et al., 

 1994). Ageing of bonefish with a 

 validated method is needed to as- 

 sess Bruger's estimates of longev- 

 ity. In addition, sex-specific differ- 

 ences in growth rates have not been 

 evaluated and growth-model pa- 

 rameters have not been estimated 

 for Florida bonefish. The only pub- 

 lished growth-model parameters for 

 bonefish are those by Morales-Nin 

 (1994), who used length-frequency 

 analyses to estimate von Ber- 

 talanffy growth parameters for a 

 small sample of bonefish from 

 Mexico's Pacific coast. In this ar- 

 ticle, we describe the age and 



