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Fishery Bulletin 101(2) 



Previous estimates of tautog fecundity by Chenoweth 

 (1963) and Stolgitis (1970) were not annual fecundity es- 

 timates (Table 6). They counted mature, transparent eggs 

 in the ovary, currently referred to as hydrated oocytes, 

 but they did not distinguish tautog as having indetermi- 

 nate annual fecundity and had no measure of spawning 

 frequency. By counting only the hydrated oocytes, these 

 investigators actually estimated batch fecundity. However, 

 it is interesting to note the similarity of batch fecundity 

 estimates (Table 6) over the period of 30 years between 

 studies and wide geographic areas, i.e. from Chesapeake 

 Bay to Narragansett Bay (550 km). 



Spawning frequency had not been previously calculated 

 for tautog with methods developed by Hunter and Macewicz 

 ( 1985). Although the hydrated oocyte method is less expen- 

 sive, it requires collection of females just prior to spawning. 

 With the hook-and-line collection method, it is difficult to 

 collect sufficient samples in a short period of time. Therefore 

 spawning frequency was estimated in our study by using 

 the POF method to read histologic preparations of ovarian 

 tissue. A female spawning every 1.2 days over the 70-day 

 spawning window would spawn on an estimated 58 days in 

 1995. Under artificial conditions, Olla et al. ( 1977) observed 

 tautog spawning on 68-96 consecutive days in laboratory 

 aquaria. Therefore, an estimate of 58 spawning days in nat- 

 ural habitats is not unrealistic. Chenoweth (1963) raised, 

 but could not answer, the question of whether individual 

 tautog spawn throughout the entire spawning season. The 

 spawning-frequency estimate presented here, and observa- 

 tions of tautog spawning on 68-96 consecutive days in labo- 

 ratory aquaria (Olla et al, 1977), indicate that tautog are 

 capable of spawning daily throughout the spawning season 

 in natural habitats under appropriate environmental condi- 

 tions (temperature, day length, etc.). 



Estimates of potential annual fecundity for Virginia 

 tautog age 3-9 ranged from 160,000 to 10,510,000 eggs. 

 However, net annual fecundity may be lower because of 

 remnant hydrated oocytes, atresia, nutritional status 

 of adult females, or environmental conditions (McEvoy 

 and McEvoy, 1992). Based on our samples (females age 

 3-9), a linear regression provided the most predictive 

 power (r2=0.81) to estimate mean annual fecundity (Fig. 

 8). Although female tautog live to be \7+ years old, it is 



estimated that 90% of tautog in Virginia waters are age 

 10 or younger (Hostetter and Munroe, 1993). Therefore, as 

 the data range in this study is similar to the age structure 

 of the resource, we suggest that the regression equation 

 (Mean AF=23,480(TL) - (SxlQi^)) is the most appropriate 

 formula for use by fishery managers for estimating annual 

 fecundity of tautog in the southern portion of its range. 



We have made a theoretical comparison of potential an- 

 nual fecundity for tautog (ages 4-9) between the northern 

 and southern areas by combining results from several stud- 

 ies in the northern range of tautog. Although commonly 

 cited as representing annual fecundity estimates, the 

 methods of Chenoweth (1963) and Stolgitis (1970) clearly 

 show that their results are batch fecundity estimates. For 

 our comparison, we selected the lowest value for age-4 

 and the highest for age-9 tautog as the sampled range 

 of batch fecundity estimates. We averaged northern data 

 from Chenoweth (1963: age 4, 265 mm TL, 6000 BF and 

 age 9, 401 mm TL, 224,000 BF) and Stolgitis (1970: age 4, 

 261 mm TL, 7000 BF and age 9, 486 mm TL, 260,000 BF) 

 to create a batch fecundity range of 6500-242,000 eggs. 

 This range was multiplied by the 68-day "spawning season" 

 observed in laboratory aquaria by Olla et al. ( 1977) to cal- 

 culate a range for potential annual fecundity of 442,000 to 

 16,456,000 eggs per female in northern areas. Our samples 

 from the southern range (age 4: 275 mm TL, 5000 BF and 

 age 9: 511 mm TL, 181,200 BF) multiplied by 58 spawn- 

 ing events in 1995 results in potential annual fecundity of 

 290,000 to 10,510,000 eggs per female. Differences in these 

 estimates of potential annual fecundity are primarily due 

 to the number of spawnings per year and are questionable 

 because the spawning frequency estimate based on aquari- 

 um studies may not apply for naturally spawning fish. This 

 comparison indicates that we still lack adequate informa- 

 tion on the spawning frequency and annual fecundity for 

 fish from the northern part of the species range. 



Although batch fecundity estimates appear similar 

 between southern and Northern portions of the tautog's 

 range, previous batch fecundity estimates from northern 

 populations are 30 years old. Reported spawning seasons 

 between areas also vary in length from two to four months, 

 which could greatly affect potential annual fecundity esti- 

 mates with this method. Estimates of annual fecundity in 



