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Fishery Bulletin 97(2), 1999 



the onset of maturity. This slowing in somatic growth 

 may reflect an allocation of energy to gonadal devel- 

 opment, or may be a response to other physiological 

 processes associated with maturation. Other 

 cynoglossid species that have been aged also mature 

 sexually at a relatively early age even in some of the 

 larger-size species. Seshappa and Bhimachar ( 1954) 

 reported that young Malabar soles (C. seryiifasciatus ) 

 grew to adult size within a year or less and that af- 

 ter maturation, growth slowed distinctly. After an 

 initially high growth rate during their first year, 

 there also occurred a marked reduction in the growth 

 rate of C. macrolepidotus during their second year, 

 at a time coincident with initiation of the spawning 

 season (Kutty, 1967). Likewise, in other cynoglossids 

 (C. arel and C. lida) occurring off India, growth dur- 

 ing the first year is also rapid and this fast growth 

 period is then followed by a considerable reduction 

 in the growth rate during the next year when the 

 fishes matured sexually (Rajaguru, 1992). In C arel, 

 for example, which reaches total lengths to 333 mm 

 SL, males and females mature at sizes of about 217 

 mm TL and 225 mm TL, respectively, sizes reached 

 by this species at the beginning of their second year 

 of life. In C. lida, size at 50^?^ maturity is 167 mm TL 

 for males, and 179 mm TL for females. These repre- 

 sent sizes that are reached by the fish during the 

 beginning of their second year of life. For C. dubiiis 

 (Seshappa, 19761 minimum size at maturity was re- 

 ported to be about 287 mm TL for females, a size 

 that corresponded to fish approximately 2-3 years 

 old. In C. canariensis, a species reaching total lengths 

 of 486 mm (males) and 519 mm (females), maturity 

 occurs at about 1.5 years when fish are about 300 

 mmTL(Chauvet, 1972). 



Hoenig's and Royce's mortality estimates, based 

 on the maximum known age of a species, indicate a 

 relatively high instantaneous total mortality in the 

 blackcheek tonguefish population inhabiting Chesa- 

 peake Bay (Table 6). Relatively few of the blackcheek 



tonguefishes within Chesapeake Bay are older than 

 three years. The age structure observed in this popu- 

 lation may, however, reflect the relatively short life 

 span of this species (5-i- years), or it could also reflect 

 high mortality levels experienced by blackcheek 

 tonguefishes in the Bay environment; undoubtedly 

 it would also be influenced by the emigration of larger 

 individuals from the Bay system. 



Relatively short life spans may be typical of spe- 

 cies of Symphiirus and of the Cynoglossidae, in gen- 

 eral. In fact, some dwarf species of tropical 

 Symphurus reach maximum sizes of only 35—45 mm 

 SL (Munroe, 1990, 1998) and probably live no more 

 than a year. Age estimates based on growth marks 

 interpreted from scales of tonguefishes occurring in 

 coastal waters off India indicate that Malabar sole 

 reach an age of only about 2+ years (Seshappa and 

 Bhimachar, 1954). Based on studies of tonguefishes 

 from the west coast of India, a life span of 3-4 years 

 was reported by Seshappa (1978, 1981) for C. lida 

 (size to 220 mm TL; most 140-189 mm TL) and C. 

 puncticeps (to 209 mm TL; most 90-179 mm TL), 

 whereas a life span of 6-i- years (to 339 mm TL; most 

 160-299 mm TL) was reported for C. bilineatus from 

 the same region. More recently, Rajaguru (1992) re- 

 ported that C. arel and C. lida along the southeast 

 coast of India have life spans just over 3 years. For 

 C. dubius off India (to 414 mm TL), age estimates 

 were 6-i- years for most individuals, although some 

 individuals reached 10 years (Seshappa, 1976). Cyno- 

 glossus arel off Taiwan (Lin, 1982) live to be at least 

 4 years. Kutty (1967) reported a maximum age of 

 6-7 years for C. macrolepidotus (to 330 mm TL). For 

 C canariensis (to 519 mm TL) off tropical West Af- 

 rica, both sexes live to at least 8 years (Chauvet, 

 1972). For the temperate species, C abbreviatus, 

 from Jiaozhua Bay, China ( Zhu and Ma, 1992 ), which 

 is commercially exploited, females reach 8 years and 

 males live to 7 years, and total mortality for this 

 population was estimated to be very high (0.607 ). For 



