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Fishery Bulletin 89(2). 1991 



trawl collections in shallow-water (<10m) estuarine 

 and mudflat habitats. However, striking differences are 

 apparent in how these species utilize inshore habitats. 

 In these habitats, juvenile 5. tessellatus are collected 

 with all life history stages of S. plagusia and 5. carib- 

 beanus. Adult S. tessellatus, however, apparently 

 undergo an ontogenetic migration from shallow, near- 

 shore habitats to deeper waters further offshore 

 (ll-80m) on the continental shelf. In contrast, although 

 a small number of S. caribbeanus and S. plagusia have 

 been taken as deep as 30-40 m on the continental shelf, 

 these were isolated captures of large adults (MIOmm 

 SL). The majority of S. plagusia and S. caribbeanus 

 (80% and 83%, respectively), including all juveniles ex- 

 amined, were collected in waters shallower than 20 m. 

 Most specimens were taken by beach seine and small 

 otter trawls at depths shallower than 10 m in nearshore 

 mudflats, mangrove habitats, and estuarine locations. 

 Symphurus oculellus, although occurring sympatric- 

 ally with S. plagusia and S. tessellatus (see Figures 3 

 and 5), apparently has a different life history than these 

 other species. Symphurus oculellus inhabits deeper 

 waters than the others (Table 11), spanning an overall 

 bathymetric range of 7-1 10 m, but being captured most 

 frequently in waters deeper than 20 m (78% collected 

 deeper than 20m). Symphurus oculellus, including 

 juveniles as small as 76 mm SL, have been collected in 

 neritic waters deeper than 7 m and none have been 

 taken from estuarine habitats, contrary to S. plagusia 

 and S. tessellatus. However, estuarine environments 

 in the geographic range of S. oculellus along north- 

 eastern South America have not been as thoroughly 

 sampled as have those nearshore habitats occupied by 

 S. plagusia and juvenile S. tessellatus in the northern 

 Caribbean and southern Brazilian areas. Symphurus 

 civitatium, the northernmost-occurring species, is the 

 only Atlantic species with a distribution allopatric to 

 those of other members of this species group. Adult 

 S. civitatium are very abundant in collections and, 

 although inhabiting a wide depth range (1-73 m), are 

 more commonly captured between 11 and 45 m on the 

 inner continental shelf where approximately 91% 

 (199/216) of the specimens examined in the present 

 study were collected (Table 1 1). It is unusual for adult 

 S. civitatium to occur in habitats deeper or shallower 

 than this depth range. For example, the deepest cap- 

 tures of this species were made at 73 and 62 m, where 

 a single fish was taken each time, and of four fish col- 

 lected in waters shallower than 10 m, only one was an 

 adult and three others were small juveniles (<35mm 

 SL). Little is known concerning early-life-history stages 

 of S. civitatium. Few juveniles have been collected, but 

 all of these were taken at inshore locations. The occur- 

 rence of early-life-history stages in nearshore waters 

 suggests a life-history pattern similar to that of S. 



tessellatus, where adults occur in deeper waters on the 

 inner continental shelf and juveniles inhabit estuarine 

 or nearshore nurseries. However, distribution data for 

 this species, especially for early juveniles, are too in- 

 complete to estimate how regularly this species utilizes 

 inshore waters as nurseries. Further investigation is 

 needed on whether recent captures of early juveniles 

 in estuarine environments represent isolated occur- 

 rences of this species or its normal life-history pattern. 



Among Symphurus, members of the S. plagusia com- 

 plex are medium- to large-sized tonguefishes, ranging 

 in maximum lengths from 122 mm SL for S. carib- 

 beanus to 220 mm SL for S. tessellatus, the second 

 largest species of tonguefish in the Atlantic (only S. 

 jenynsi from the southern South Atlantic exceeds these 

 sizes) and third largest in the genus (Fig. 2). Symphu- 

 rus caribbeanus and S. plagusia are the smallest of the 

 five Atlantic species of this complex (122 and 130 mm 

 SL, respectively), and also mature at the smallest sizes 

 (70-80 mm SL for S. caribbeanus; 80mm SL for S. 

 plagusia). Symphurus civitatium is only slightly larger, 

 attaining maximum lengths of ~ 152 mm SL and matur- 

 ing at sizes slightly greater than 90 mm SL. Symphurus 

 oculellus and S. tessellatus are the largest Atlantic 

 species in this complex, attaining maximum sizes of 189 

 and 220 mm SL, respectively. Not surprisingly, these 

 larger-sized species also mature at somewhat larger 

 sizes. Female S. oculellus mature at about 110 mm SL 

 and female S. tessellatus at 104-120 mm SL. 



Comparisons of ecological and life-history param- 

 eters, like those above, supplement and corroborate 

 systematic determinations based on morphological 

 evidence. However, in the absence of a cladistic 

 hypothesis, the value of these ecological comparisons, 

 especially concerning historical relationships, either of 

 the species complex within the genus or of the indi- 

 vidual species comprising the S. plagusia complex, can- 

 not be fully assessed. Further study, based on shared 

 derived characters using outgroup comparisons or 

 ontogeny, is needed before intrageneric relationships 

 of the species complex and interrelationships of its 

 members can be determined to better understand 

 trends in the evolution of life-history attributes of these 

 tonguefishes. 



Acknowledgments 



This work, initially comprising a portion of a disserta- 

 tion submitted as partial requirement for the Ph.D. 

 degree at the College of William and Mary, was en- 

 hanced during my tenure as a Post-doctoral research 

 fellow in the Division of Fishes, National Museum of 

 Natural History, Smithsonian Institution. The final 

 manuscript was rewritten after my arrival at the Sys- 



