Terwilliger and Munroe: Age, growth, longevity, and mortality of Symphurus plagiusa 



353 



for females and 0.223 for males 

 were reported (Rajaguru, 1992). 

 For C. abbreviatus (Zhu and Ma, 

 1992), /C- values were 0.395 for fe- 

 males and 0.344 for males. In two 

 of the largest species in the fam- 

 ily, C. semilaevis and C. canar- 

 iensis. the estimated /C-values 

 were higher for males compared 

 with those for females. In C. 

 semilaevis, K-value for females 

 was 0.264, and that of males was 

 0.352 (Meng and Ren, 1988). For 

 female C. senegalensis the K- 

 value was 0.32 compared with 

 0.36 for males (Chauvet, 1972). 

 In Chesapeake Bay, blackcheek 

 tonguefishes achieve most of 

 their growth in length during 

 their first year. Males and fe- 

 males attained up to SO^f of 

 their total growth in length by 

 the end of their first year, and 

 up to 72% of their total growth 

 by the end of their second year. 



Such rapid first-year growth does not appear to be 

 unusual among members of the Cynoglossidae. For 

 example, male C. arel grew between 180-194 mm 

 TL, and females from 201-210 mm TL, during their 

 first year (Rajaguru, 1992), which represented up to 

 58% and 51% of their total growth in length (333 

 and 393 mm, respectively). Similar to the pattern 

 observed in blackcheek tonguefish, second-year 

 growth in this species was estimated to be only 18% 

 and 21% of the total growth, respectively, for males 

 and females. In C. lida, males (151-154 mm TL) and 

 females (153-156 mm TL) also reached fairly large 

 sizes during their first year of life, with first-year 

 growth for males and females ranging between 69 

 and 71% of the total growth in length (216 and 218 

 mm, respectively), compared with second-year 

 growth values of only 13-14% of the total length 

 (Rajaguru, 19921. Cynoglossus macrolepidotus also 

 has a high growth rate during its first year, reach- 

 ing a length of about 160 mm TL, and like the pre- 

 ceding species, during the second and subsequent 

 years there occurs a marked reduction (only 10-30 

 mm increase/yr) in growth rate (Kutty, 1967). Like- 

 wise, in C. abbreviatus (Zhu and Ma, 1992), first- 

 year growth is maximal for both sexes (males to 162 

 mm TL, females to 178 mm TL; representing 50% 

 and 51% of total growth, respectively), whereas sec- 

 ond-year growth in this species averages only about 

 16% or less of the total growth. This growth pattern 

 was also apparent for C. canariensis where male and 



female fish, respectively, achieved 50%c and 55%f of 

 their total growth in length during the first year, 

 compared with second-year growth equalling only 

 14-15% of the total growth in length (Chauvet, 1972). 

 In another large-size species, C. semilaevis, first-year 

 growth is also rapid, with males reaching 141 mm 

 TL at end of year one and females growing to 194 

 mm TL, values that represent 45% and 30% of the 

 total growth in length achieved by this species (Meng 

 and Ren, 1988). However, in contrast to other 

 cynoglossid species examined thus far, growth in this 

 species during the second year differs markedly be- 

 tween the sexes. For females, the average growth 

 increment during the second year was greater than 

 that of the first year (to 307 mm TL, 36% of total 

 growth in length), whereas during this same time 

 interval males averaged only about one-half of the 

 growth increment attained during year one (to 204 

 mm TL, representing 20% of total growth). In the 

 hogchoker, growth in length is also rapid; males and 

 females achieve 56% and 44% of their total growth 

 in length during the first year (Koski, 1978). By the 

 end of their second year, hogchokers have reached 

 on average 74% (males) and 63% (females) of their 

 total growth in length. 



The substantial reduction in growth rate beyond 

 age 1 noted for blackcheek tonguefishes occurs at a 

 time coincident with maturation (Terwilliger, 1996). 

 Roff (1982) noted that, for fish in general, it is fre- 

 quently observed that rate of growth decreases with 



