56 



Fishery Bulletin 91 1 1), 1993 



Table 8 



von Bertalanffy growth functions derived for Tautoga onitis 

 collected in Virginia (1979-86) and Rhode Island (from Coo- 

 per 1965). 



Virginia tautog 



(males, rc=398) K 

 to 



L, 



(females, n=281) K 



to 



L, 



Rhode Island tautog 



(males, rc=1041) L, 

 (females, n=1119) L, 



0.090. L. = 732 

 -1.644 



732 [l-e^" 90 " 416441 ] 

 0.085, L,., = 733 

 -1.743 



733[ 1-e -"""■•"•' 7,J, I 



_ 66411-e -009108 "* 1 66238 '] 

 = 506[l-e J " 51,,i " uo95220, ] 



timated for tautog in Rhode Island (Cooper 1965) indi- 

 cated appreciably smaller L„ values (506 mm and 

 664 mm) for both sexes compared with those estimated 

 for tautog in Virginia. 



The present study also found that males grow at a 

 somewhat faster rate than females. Cooper ( 1965) found 

 a slightly faster growth rate in females when com- 

 pared with males (Table 8). However, in both studies 

 estimated if-values are comparable. Similarities in K- 

 values between tautog occurring in Rhode Island and 

 Virginia support the contention that growth rate (K) is 

 an intrinsic value for the species, largely independent 

 of geographic location. 



Although Cooper (1965) found that females initially 

 grew at a faster rate than males, he reported diver- 

 gence in growth between sexes favoring faster growth 

 in males after age-3. We also found similar divergence 

 in growth of males, but unlike Cooper's study, this 

 difference was apparent for males at all ages. 



In our study area, males live longer than females. 

 The oldest fish examined were a male estimated to be 

 age-25 and a female estimated to be age-21. Cooper 

 ( 1967) indicated a life span of 34 yr for males and 22 yr 

 for females in the population he studied in Rhode Is- 

 land, and suggested that females may reach senes- 

 cence at an earlier age than males. Although longevity 

 estimates of tautog based on actual data range be- 

 tween 25 and 34 yr, most fish aged were considerably 

 younger than this, and it seems that claims of fish 

 more than a half century old (Reiger 1985) are exag- 

 gerated. Average age for tautog in this study was just 

 over 7yr; 82% of the fish were age-10 or younger, only 

 \' r were age-20 or older. Cooper (1967) found a similar 

 age structure in the population of tautog residing in 

 Narragansett Bay just over 25 yr ago, where approxi- 

 mately only 157c and 8% of males and females, respec- 

 tively, were older than age-13. The current world record 



for tautog (IGFA 1990) was a fish taken by rod-and- 

 reel off Virginia measuring 819mmTL (-10.89 kg). 

 Within constraints of the von Bertalanffy equation and 

 length-weight relationship derived for tautog from Vir- 

 ginia waters, we estimate an age for this fish of -30 yr, 

 which is comparable to the maximum age (34yr) re- 

 ported for the species (Cooper 1967). 



Weight-at-age estimates for tautog, as a measure of 

 growth, were much more variable than length esti- 

 mates. This variation is attributed to different stages 

 in ontogenetic development, as well as differences in 

 sex, maturity, and age. Geographic location and asso- 

 ciated environmental conditions, such as seasonality 

 (date and time of capture), stomach fullness, disease 

 and parasite loads (Le Cren 1951, Bagenal & Tesch 

 1978), can also affect weight-at-age estimates. Since 

 these factors contribute significant variation to regres- 

 sion relationships of WT on TL, interpretation of dif- 

 ferences in these data between populations must be 

 viewed with caution. 



Direct comparisons of our length-weight data with 

 those of Cooper (1967) were not feasible due to sam- 

 pling differences (Cooper used eviscerated weights of 

 fish). However, in a study of tautog from coastal 

 waters off New York, Briggs ( 1969 ) calculated a length- 

 weight relation based on uneviscerated weights of over 

 3000 fish collected during several seasons (May- 

 November) over a 3yr period. Although Briggs did not 

 present data for individual sexes, comparisons of data 

 combined for both sexes are still possible (Table 9). 

 From these comparisons, it is evident that the length- 

 weight relationship for tautog from Virginia waters is 

 similar to that estimated for tautog from off New York. 



