OLLA ET AL.: FEEDING BEHAVIOR OF THE CUNNER 



substrate. These structures would be most effec- 

 tive when placed where both forage species and 

 fish species may be recruited naturally, the only 

 element having prevented their presence 

 previously being the absence of the structure. 



The most obvious difference in the feeding 

 habits of cunner and tautog is the greater diver- 

 sity of organisms eaten by cunner (Table 3). While 

 MjitUui^ ednlxA makes up the bulk of the diet dur- 

 ing the feeding year of the tautog, it comprises a 

 significant part of the cunner diet only during May 

 and June. For the remainder of the feeding year, 

 Idotea haltica predominates, with a variety of 

 other invertebrates and fish being ingested by the 

 cunner. The food habits of these fish not only show 

 a change of season, as in this study, but also vary 

 widely with geographic location. Comparing the 

 results of this study with those of Richards (1963) 

 in Long Island Sound and Chao (1973) at Nahant, 

 the diversity in the cunner's feeding is even more 

 apparent. 



The more diverse diet of the cunner as compared 

 with the rather restricted one of the tautog in this 

 particular habitat may in part be related to 

 morphological differences between the two 

 species. The cunner, with its narrower, more 

 streamlined body, pointed snout, and thinner lips, 

 is well suited for feeding on the small motile crus- 

 taceans, e.g., /. baltica, occurring both benthically 

 and in the water column. Davis and Birdsong 

 (1973) in their review of water column foraging in 

 coral reef fishes show morphological differences 

 distinguish water-column foragers from benthic 

 foragers within the same family. 



The depletion of specific foods such as M. edulis 

 (011a et al. 1974) in this community, would appear 

 to be far more detrimental to tautog than to 

 cunner. Competition for the same food items 

 would likely occur only during May and June. 



Shifts in feeding habits may relate to other 

 variables besides obvious differences in the abun- 

 dance of the forage species. For example, /. baltica, 

 occurring in waters of Denmark, shift their daily 

 rhythm of activity on a seasonal basis while held in 

 the laboratory (H^rlyck 1973). In the spring this 

 species is primarily nocturnal; during late spring 

 and early summer the species becomes more active 

 by day. The cunner, which feeds by day, ingested 

 significantly larger amounts of /. baltica during 

 approximately the same time that this species had 

 changed to a diurnal activity pattern. Of course 

 this is, at best, conjecture, since it is not well un- 

 derstood how closely these laboratory observations 



relate to the field and whether this species would 

 show the same seasonal shift in such widely 

 separated geographic locations. 



All of the cunner tracked and observed directly 

 remained within several meters of some structure. 

 This behavior agreed with earlier observations on 

 young tautog (<250 mm; 011a et al. 1974). Further- 

 more, we found that tautog of this size and cunner 

 of all sizes studied (50-240 mm) remained inshore 

 during the winter in a torpid state, agreeing with 

 the observations of Green and Farwell (1971). Ap- 

 parently, the home range for cunner of this size is 

 restricted throughout all seasons to the length and 

 breadth of the structure to which they were 

 originally recruited. 



Offshore reefs (primarily shipwrecks) appear to 

 support a population of older and larger cunner 

 than are found in inshore waters. During trawl 

 vessel surveys conducted by the Northeast 

 Fisheries Center (see Grosslein 1969 for a descrip- 

 tion of the survey program) cunner, 21 to 42 

 cm, have been collected at stations approximately 

 100 km southeast of Cape Cod, Mass. These larger 

 fish do not represent any significant part of the 

 cunner population as far as is known at this time, 

 but it is of interest that they do exist. Whether 

 they were originally recruited to these offshore 

 areas and remained there, or were part of an 

 inshore population that moved offshore when 

 reaching a certain size (as is the habit of older 

 tautog) and then remained there, can only be sur- 

 mised. 



LITERATURE CITED 



Briggs, p. T., and C. S. Zawacki. 



1974. American lobsters at artificial reefs in New York. N.Y. 

 Fish Game J. 21:73-77. 

 Chao, L.N. 



1973. Digestive system and feeding habits of the cunner, 

 Tautogolabrufi adspersus, a stomachless fish. Fish. Bull., 

 U.S. 71:565-586. 



COLLETTE, B. B., AND F. H. TaLBOT. 



1972. Activity patterns of coral reef fishes with emphasis on 

 nocturnal-diurnal changeover. Nat. Hist. Mus. Los Ang. 

 Cty.,Sci. Bull. 14:98-124. 



Davis, W. P., and R. S. Birdsong. 



1973. Coral reef fishes which forage in the water column: a 

 review of their morphology, behavior, ecology and evolu- 

 tionary implications. Helgolander wiss. Meeresunters. 

 24:292-306. 



Green, J. M., and M. Farwell. 



1971. Winter habits of the cunner, Tautogolabrus adxpersus 

 (Walbaum 1792), in Newfoundland. Can. J. Zool. 

 49:1497-1499. 

 Grosslein, M. D. 



1969. Groundfish survey program of BCF Woods 

 Hole. Commer. Fish. Rev. 31{8-9):22-30. 



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