FOOD AND FEEDING OF 



THE TOMTATE, HAEMULON AUROUNEATUM 



(PISCES, HAEMULIDAE), IN 



THE SOUTH ATLANTIC BIGHT' 



The tomtate, Haemulon aurolineatum, is an abun- 

 dant demersal fish in a variety of marine habitats in 

 the South Atlantic Bight, the Gulf of Mexico, and the 

 Caribbean Sea (Darcy 1983). They are a reef-associ- 

 ated species (Parrish and Zimmerman 1977), and in 

 the South Atlantic Bight they are most commonly 

 found over hard or "live" bottom reefs in depths 

 < 55 m (Struhsaker 1969; Manooch and Barans 

 1982; Sedberry and Van Dolah 1984). While occa- 

 sionally taken in trawl catches over open, sandy 

 habitats on the southeastern continental shelf (Wen- 

 ner et al. 1980), they are much more abundant in 

 trawls directed at sampling hard bottom, and 

 generally rank in the top three demersal species by 

 number or weight in trawl catches (Wenner 1983; 

 Sedberry and Van Dolah 1984; Sedberry unpubl. 

 data). Although they are frequently caught on hard 

 bottom reefs in the South Atlantic Bight, the depen- 

 dance of these fishes on hard bottom habitat for food 

 is unknown. Previous investigations in the Carib- 

 bean have indicated that tomtate are not obligatory 

 reef dwellers and that they forage extensively in 

 open sandy areas (see Darcy 1983 for review). 

 Because of the importance of this species in the hard 

 bottom ichthyofauna of the South Atlantic Bight and 

 its importance to fisheries associated with hard bot- 

 tom reefs, a knowledge of its food habits is important 

 to our understanding the ecology of this habitat. 

 Tomtate may be important in transferring energy 

 from the expansive sand areas of the shelf onto the 

 much more restricted hard bottom habitat, and their 

 feeding behavior in the South Atlantic Bight may be 

 important in maintaining the higher biological pro- 

 ductivity of hard bottom areas, relative to the open 

 sandy shelf. 



To determine foraging habitat of the tomtate, an 

 investigation on food habits was conducted. The pur- 

 pose of this note is to report the results of that study 

 and to relate the feeding behavior to existing 

 knowledge of the ecology of hard bottom areas in the 

 South Atlantic Bight. 



Methods 



Tomtate were collected during seasonal cruises in 

 1980 (two cruises- one in winter and one in summer) 



and 1981 (four cruises- one each in winter, spring, 

 summer, and fall) by trawl from eight hard bottom 

 reef stations off South Carolina and Georgia. Sta- 

 tions were located in each of three depth zones 

 representing the inner shelf (16-22 m depth, three 

 stations), middle shelf (23-38 m, four stations), and 

 the outer shelf (47-67 m, one station). Detailed 

 descriptions of station locations and habitat can be 

 found in Sedberry and Van Dolah (1984) and Wen- 

 ner et al. (1984). Each station was mapped 

 using loran C and underwater television, and all sam- 

 pling was conducted in hard bottom areas mapped by 

 using this technique (Sedberry and Van Dolah 1984). 



Tomtate were measured (standard length, SL) at 

 sea and their stomachs removed if not conspicuously 

 empty. Stomachs were individually labeled and pre- 

 served in 10% seawater-Formalin^. 



Stomachs were washed in tap water and transfer- 

 red to 50% isopropanol in the laboratory, and con- 

 tents of individual stomachs were sorted by taxa and 

 counted. Colonial forms (e.g., hydroids, bryozoans) 

 and algae were counted as one organism. Volume 

 displacement of food items was measured using a 

 graduated cylinder, or estimated by using a 0.1 cm^ 

 grid (Windell 1971). 



Since the methods of food habits quantification are 

 variously biased (Hynes 1950; Pinkas et al. 1971; 

 Windell 1971), the relative contribution of different 

 food items to the total diet was determined using 

 three methods: 1) percent frequency occurrence (F), 

 2) percent numerical abundance (N), and 3) percent 

 volume displacement (V). These three values were 

 calculated for individual prey species, for prey 

 grouped by higher taxonomic categories, and for 

 higher taxonomic categories pooled for 100 mm 

 intervals of standard length. To determine the 

 dependance of tomtate on hard bottom prey 

 organisms, stomach samples were compared with 

 benthic samples using IvleVs index of electivity 

 (Ivlev 1961), calculated as follows: 



E = 



^1 



A +^2 



where P, is the percentage of the diet comprised by a 

 given prey taxon and P2 is the percentage of the food 

 complex in the environment (i.e., in benthic samples) 

 comprised by the same prey taxon. Electivity values 

 range from - 1 to -i- 1 . Negative values imply that 

 the prey species is avoided by the predator or that it 



^Contribution No. 179, South Carolina Marine Resources 

 Research Institute, P.O. Box 12559, Charleston, SC 29412. 



^Reference to trade names does not imply endorsement by the Na- 

 tional Marine Fisheries Service, NOAA. 



FISHERY BULLETIN: VOL. 83, NO. 3, 1985. 



461 



