MANOOCH and BARANS: DISTRIBUTION AND ABUNDANCE OF TOMTATE 



seemed low. Therefore, we plotted log f (L^ — /,) 

 against t by using trial values of L x ranging from 

 285 to 310 mm. The straightest line resulted 

 from L x of 310 mm. The slope of the line, 

 —0.22017, was selected as the growth coefficient 

 {K) and was used to obtain U (—1.28). Our best 

 estimate of the equation describing the theoreti- 

 cal growth of tomtates is 



It = 310 (1 - exp - 0.22017(* + 1.28)). 



annual mortality estimate for 1972 through 1978 

 was 59% (Z = 0.887). By year, instantaneous mor- 

 tality rates were 1974, 0.669; 1975, 1.035; 1976, 

 1.017; 1977, 1.041; and 1978, 0.972. Too few fish 

 were sampled from the fishery in 1972 and 1973 

 to construct catch curves. The instantaneous 

 mortality rate(s) for tomtates was higher than 

 those previously obtained for white grunt, Z = 

 0.65 (Manooch 1976), or for red porgy, Z= 0.58 

 (Manooch and Huntsman 1977). 



Observed, back-calculated, and theoretical 

 lengths at age are presented in Table 9. 



Table 9.— Total lengths of tomtates at age (ob- 

 served, back-calculated, and theoretical). 



Age 



Length at age (mm) 



Observed 



Back-calculated Theoretical 



Length- Weight and Fork Length- 

 Total Length Relationships 



Fish ranging from 52 to 280 mm TL were used 

 to calculate a length-weight relationship. The 

 equation 



W = 0.0000086L 30905 , r = 0.996 and N = 70, 



where W = weight in grams and L = total 

 length in millimeters, describes this relation- 

 ship. The equation TL = -1.8196 + 1.1540 FL, 

 r = 0.99 and TV = 100 was derived to convert 

 lengths. 



Mortality Estimates 



By age IV, tomtates are fully recruited to the 

 hook and line fishery, the only important method 

 of harvesting this species off the southeastern 

 United States. Instantaneous mortality (Z) esti- 

 mates were obtained by analyzing catch curves 

 of fish aged IV and older (Fig. 8). The mean total 



7.0 

 6.0 



> 



O 5.0 



z 



Ul 



P. 4.0 



a 3.0 



o 



o 



2.0 

 1.0 



N= 1.496 

 Z=-0.887 

 r= -0.985 



m 



E 



m 



2n 2m ix 



AGE 



Figure 8. — Catch curve for tomtates caught by hooked line 

 off the southeastern United States, 1974-77. 



Spawning 



Indirect evidence indicates that tomtates of 

 the South Atlantic Bight spawn primarily in 

 April and May. Running ripe males and partly 

 spent females were caught in April 1979 (28-42 

 m; 16.4°-19.4°C), while a major decrease in mean 

 ovarian weight and maximum ovary weight of 

 mature females occurred after the spring (April 

 1974) sampling period (Table 10). Throughout 

 the year, many (>38%) of the females sampled 

 each season were in the maturing and ripe condi- 

 tion. The presence of juveniles (33-90 mm TL; 

 mode 80 mm) in bottom trawl collections during 

 summer, and the progressive increase in modal 

 fish lengths in length-frequency distributions 



Table 10.— Gonad condition of adult tomtates (>15 cm TL) 

 from the South Atlantic Bight. 



'Gonad index = (ovary wt./fish wt.) X 100. 

 2 Females 77% with hydrated eggs. 



13 



