W&M ScholarWorks VIMS Articles 1999 Age, Growth, Longevity, And Mortality Of Blackcheek Tonguefish, Symphurus Plagiusa (Cynoglossidae : Pleuronectiformes), In Chesapeake Bay, Virginia Mark R. Terwilliger Virginia Institute of Marine Science Thomas A. Munroe Follow this and additional works at: https://scholarworks.wm.edu/vimsarticles Part of the Aquaculture and Fisheries Commons Recommended Citation Terwilliger, Mark R. and Munroe, Thomas A., "Age, Growth, Longevity, And Mortality Of Blackcheek Tonguefish, Symphurus Plagiusa (Cynoglossidae : Pleuronectiformes), In Chesapeake Bay, Virginia" (1999). VIMS Articles. 586. https://scholarworks.wm.edu/vimsarticles/586 This Article is brought to you for free and open access by W&M ScholarWorks. It has been accepted for inclusion in VIMS Articles by an authorized administrator of W&M ScholarWorks. For more information, please contact [email protected]. 340 Abstract.–Age structure, longevity, and mortality were determined for a Age, growth, longevity, and mortality of population of blackcheek tonguefish, blackcheek tonguefish, Symphurus plagiusa Symphurus plagiusa, in Chesapeake Bay. Blackcheek tonguefish (36–202 (Cynoglossidae: Pleuronectiformes), mm TL) were randomly collected by means of otter trawl in lower Chesa- in Chesapeake Bay, Virginia* peake Bay and major Virginia tributar- ies (James, York, and Rappahannock rivers) from April 1994 through August Mark R. Terwilliger 1995. Ages were determined by inter- School of Marine Science, Virginia Institute of Marine Science preting growth increments on thin College of William and Mary transverse sections of sagittal otoliths. Gloucester Point, Virginia 23062 Marginal increment analysis showed Present address: 104 Nash Hall that a single annulus was formed in Department of Fisheries and Wildlife June of each year. Blackcheek tongue- Oregon State University fish caught during this study reached Corvallis, Oregon 97331 a maximum age of 5+ years. Growth E-mail address: [email protected] was rapid during the first year, then slowed rapidly at a time coincident with maturation. We used the following von Thomas A. Munroe Bertalanffy growth equations: for National Marine Fisheries Service National Systematics Laboratory, MRC-153 –0.285(t + 0.92) National Museum of Natural History males—Lt = 196.5(1 – e ); and –0. 320(t + 0.78) Washington, D.C. 20560 for females—Lt = 190.6(1 – e ). Von Bertalanffy parameters were not significantly different between sexes. Extrapolated instantaneous mortality rates for a possible seventh year class were 0.73 (Hoenig’s equation) and 0.77 (Royce’s equation). High estimates of The blackcheek tonguefish, Sym- This species is among the top three instantaneous total mortality may re- phurus plagiusa (Linnaeus, 1766), most abundant pleuronectiforms flect either loss due to emigration of ranges from Connecticut southward occurring throughout lower Chesa- adults from Chesapeake Bay onto the through the Florida Keys, northern continental shelf or high natural mor- peake Bay and its tributaries tality occurring in this northernmost Gulf of Mexico, Cuba, and the Ba- (Bonzek et al., 1993; Geer et al., population. Compared with sympatric hamas (Ginsburg, 1951; Topp and 1997). Only the hogchoker, Trinectes pleuronectiforms, blackcheek tongue- Hoff, 1972; Munroe, 1998). Chesa- maculatus, is commonly taken in fish have a relatively high mortality peake Bay is the northernmost lo- greater abundance in bottom trawls rate, small asymptotic length, and high cation of a major population of this growth parameter K. Species, such as made within the Bay. Occurrence of blackcheek tonguefish, that feature this species (Munroe, 1998). South of all life history stages in Chesapeake combination of growth parameters are Chesapeake Bay, blackcheek tongue- Bay (Olney and Grant, 1976; Ter- hypothesized to be better adapted at fishes are an abundant component of williger, 1996) suggests that black- exploiting seasonally dynamic and the fish fauna occurring in estuaries cheek tonguefish is a resident spe- highly unpredictable environments, and inshore coastal waters. Within such as those estuarine habitats within cies in this system. Chesapeake Bay. this region, they occur in sufficient Despite its abundance in differ- numbers to form a minor component ent estuarine and nearshore marine of the bycatch of demersal fisheries habitats in the northwest Atlantic, and also constitute a minor inclu- life history parameters of S. pla- sion in landings reported for several giusa are largely unknown. Some industrial fisheries. In the shrimp previous works have described dis- trawl fishery, they are a potential tribution, relative abundances and nuisance because individuals fre- length frequencies for blackcheek quently become embedded in the tonguefish in South Carolina estu- webbing of trawls to such an extent aries (Shealy et al., 1974); some that they interfere with the gear’s have summarized size-related ma- effectiveness (Topp and Hoff, 1972). turity patterns for individuals from The blackcheek tonguefish is the throughout the entire range of the only member of the pleuronectiform species (Munroe, 1998); some have family Cynoglossidae occurring in * Contribution 2203 of the Virginia Institute Manuscript accepted 15 June 1998. Chesapeake Bay (Ginsburg, 1951; of Marine Science, College of William and Fish. Bull. 97:340–361 (1999). Murdy et al., 1997; Munroe, 1998). Mary, Gloucester Point, VA 23062. Terwilliger and Munroe: Age, growth, longevity, and mortality of Symphurus plagiusa 341 investigated factors influencing recruitment (Miller tal constancy precludes the formation of interpret- et al., 1991); and some have described daily growth able annular growth marks on these structures rates of juveniles in Georgia estuaries (Reichert and (Qasim, 1973). Other species of symphurine van der Veer, 1991). The minimal amount of pub- tonguefishes that occur in temperate waters gener- lished information on this species (summarized in ally are small-size, deep-water forms that are diffi- Munroe, 1998) may be due in part to the relatively cult to catch in abundance (Munroe, 1998). small size of the fish. It reaches a maximum size of This study was undertaken to determine age struc- approximately 210 mm total length (TL) (Wenner and ture, growth rate, longevity, and mortality for a popu- Sedberry, 1989), but fish smaller than 165 mm TL lation of S. plagiusa residing in Chesapeake Bay, are those most commonly taken in Chesapeake Bay Virginia. Knowledge about life history parameters by otter trawl (Terwilliger, 1996; Geer et al., 1997). for this species provides a window of understanding Small size and benthic microinvertebrate feeding into the biology of the Cynoglossidae, as well as in- habits (Stickney, 1976; Reichert and van der Veer, sights into age, growth, and longevity of other small- 1991; Toepfer and Fleeger, 1995) render this species size, estuarine-dependent flatfishes. inaccessible to most recreational and commercial fishing gears used in Chesapeake Bay. Few age and growth studies using bony structures Materials and methods or otoliths exist for species of the Cynoglossidae. This relatively large gap in knowledge for approximately Blackcheek tonguefishes were collected by 9.14-m 150 species of tonguefishes was recently noted in a semiballoon otter trawl with a 38.10-mm stretch compilation of flatfish life history parameters (Miller mesh body, 6.35-mm mesh codend liner, and attached et al., 1991). Although several studies have described tickler chain (Bonzek et al., 1993). Fish were collected growth for species of Cynoglossus from the eastern from April 1994 through August 1995 during the Vir- Atlantic (Chauvet, 1972), western Pacific (Lin, 1982; ginia Institute of Marine Science (VIMS) Juvenile Meng and Ren, 1988; Zhu and Ma, 1992), and In- Finfish and Blue Crab Stock Assessment Program’s dian Ocean (Seshappa, 1976, 1978, 1981; Ramana- trawl survey. The survey employs a monthly, ran- than et al., 1980; Seshappa and Chakrapani, 1984), dom-stratified design of the lower Chesapeake Bay no growth studies using bony structures or otoliths and fixed-station mid-channel transects in each of have been performed on species of Symphurus. Pre- three major Virginia tributaries: the York, James, vious work describing the age structure of blackcheek and Rappahannock rivers (Fig. 1). Details of sam- tonguefish in Chesapeake Bay using length frequen- pling design were provided in Geer et al. (1993). cies of fish taken by otter trawl (Bonzek et al., 1993) Samples of blackcheek tonguefishes selected from is limited because this type of analysis requires sub- trawl catches were brought to the laboratory, measured jective interpretation of modal frequencies in the for total length (TL) to the nearest millimeter and for data, which, given the difficulty of distinguishing total weight (TW) taken to the nearest hundredth of a modal groups at older ages, renders the interpreta- gram. When samples were small, all fish were used in tion unreliable (Chauvet, 1972; White and Chitten- age analyses; however, fish were randomly selected for den, 1977; Jearld, 1983; Barbieri, 1993). Such limi- age analyses from relatively large samples. Regressions tations in interpretation of age from length-frequency were fitted to the length–weight data, and regressions distributions are particularly evident in data from on log-transformed data for male and female blackcheek Koski’s (1978) study on hogchokers from the Hudson tonguefish were compared by using analysis of covari- River