Lowerre-Barbien et al.: Age and growth of Cynosaon regalis 



651 



Table 5 



Von Bertalanffy model parameter estimates, standard er- 

 rors and 95^ confidence intervals estimated for weakfish, 

 Cynoscion regalis, in the Chesapeake Bay region collected 

 in April and May 1989-93. 



Parameter 

 K 



tn 



12 and as large as 875 mm TL were observed. Popu- 

 lation size and age compositions could not be esti- 

 mated from our samples, because they were not ran- 

 domly selected and came from several gear types. How- 

 ever, our samples should represent the population 

 range. Hildebrand and Schroeder (1928) reported a 

 similar size range ( 76-838 mm TL, n =280 ) in the 1920's. 

 However, Massmann ( 1963 ) reported most weakfish in 

 the 1950s were <300 mm TL, with a maximum size of 

 445 mm TL (rc=14,516) and a maximum age of 5. 



Chesapeake Bay weakfish are fully recruited to 

 market grades by age 2. Joseph ( 1972 ) also reported 

 age 2 as the first age fully recruited to the Chesa- 

 peake Bay pound net catch. However, yearlings some- 

 times make up a large portion of the commercial 

 catch, as we observed in 1990, and clearly are vul- 

 nerable to the gear — especially pound nets and haul 

 seines. Such small, young fish are often sold as scrap 

 and do not show up in market grades. McHugh ( 1960 ) 

 found weakfish to be the second most important food 

 fish in scrap from the Chesapeake Bay pound-net 

 fishery, and Massmann ( 1963 ) reported the number 

 of weakfish in pound-net scrap often exceeded that 

 in market grades. Thus, although Chesapeake Bay 



weakfish are fully recruited to market 

 grades at age 2, age at recruitment to 

 pound nets and haul seines is younger. 



Large, older weakfish occur seasonally 

 in Chesapeake Bay. From 1989 to 1992, 

 older fish ( ages 4 and older) were relatively 

 abundant only in April and May. Hilde- 

 brand and Schroeder (1928) and Mass- 

 mann ( 1963) also reported seasonal avail- 

 ability of large weakfish in Chesapeake 

 Bay. Although Massmann ( 1963 ) collected 

 few weakfish >2 lb (0.91 kg) or age 4, the 

 largest fish in his study (2- and 3-year- 

 olds) were relatively more abundant in 

 April and May, similar to the present 

 study. However, Hildebrand and Schroeder 

 ( 1928) reported weakfish >3 lb ( 1.36 kg) to 

 be more common in both spring and late fall. Thus, 

 although large fish occur regularly in the spring, their 

 appearance in the fall may be variable. 



2000 



1000 



Delaware Bay 



B nig 



S 32 kg 

 D 4 6 kg 



 SO kg 



wgH 



Chesapeake Bay 



1960 



1970 



1980 



1990 



Year 



Figure 10 



Number of weakfish, Cynoscion regalis, citations reported 

 in the Delaware Sport Fishing Tournament and the Vir- 

 ginia Saltwater Fishing Tournament, 1958-92. Minimum 

 citation weights are indicated by year. In 1972, the Dela- 

 ware citation weight changed mid-year from 1.4 to 2.3 kg. 



