NATURAL HISTORY OF THE SANDBAR SHARK 



29 



precludes description of the growtii as deternii- 

 nato, at least for the fireat haimueriiead. One 

 iiidividiial. measured but not included in tlie 

 sample, was 18 feet lonjj. Although the continua- 

 tion of frrowth after maturity as a peculiarity of 

 tlie female api)arently does not obtain in E. mil- 

 mcrti. it is-,evidently,the pattern. in some species 

 of Sphi/rna.irr^'fi'rolannops, and occasionally in 



;■-•/<, V <- t. 

 FOOD AND FEEDING HABITS 



■Examination of stomachs of Eulamia milhertr 

 as a source of information on the ftfod of the 

 species has been disappointing. (Comparison of 

 the feeding habits of E. mUhcrti w^th the feeding 

 Wbits of other carclmrhinid species of the 

 FSoi'ida region, however, has provficl to be more 

 illuminating, vai'ious bits of evidence sliow that 

 Ej. m'ttUerti is a discriminating feeder; that it is a 

 bottom feeder; that it feeds on small bottom fish 

 and invertebrates rather than the larger ones; 

 that it prefers fresh fish to stale or decomposed 

 fish; that it ju'efers fish to porpoise meat or to 

 tlie flesli of domestic animals; and that its feed- 

 ing is remarkably successful in comparison with 

 some of its larger carcharhinid relatives. 



A very large proportion of the sharks in com- 

 mercial landings were found to have empty stom- 

 achs. An obvious explanation for this is that 

 most of the sharks were examined after the pas- 

 sage of several hours when small and readily 

 digestible meals would presumably have been 

 completely hydrolized. Observations and exami- 

 nations of stomachs of sharks of many species 

 lias led me to the opinion that the larger species 

 find food less often than the small ones, and that , 

 tiirough no choice of their own. large .sharks have ^4 

 empty stomachs more often than not. "^'^.^"^^-^i) 



In the stomachs of EuTamm mUherti a few fish 

 remains, usually not identifiable as to species, 

 cepjialopods, and crustacean remains were found 

 from time to time. Goatfishes (Mullidae), snake 

 eels (Ophichthyidae), sea robins (Triglidae), and 

 cusk eels (Ophidiidae). wei'e among the types 

 most commonly found. A collection of 107 mU- 

 h< rti, all with fish, octopus, or crabs in their 

 stomachs was reported in an earliei- publication 

 (Springer, 1946). There were unusual circum- 

 stances about tliis catch, however, whicji suggest 

 tliat the large amount of food in the stomachs 



resulted from the sharks being taken in an area 

 of localized upwelling that had stunned large 

 numbers of fish and bottom invertebrates. Very 

 few instances were noted in which shark remains 

 were found in milhertj stomachs and no evidence 

 was found that ithilberti connnonly fed on large 

 tuitles, porpoises, birds, ships' garbage, or sur- 

 face material recognized by the inclusion of 

 Sargassum weed or typical surface-dwelling 

 forms. 



Some indication of the probable food prefer- 

 ences of E, miJberfi can be found in the experi- 

 ences of commercial fishermen. It was demon- 

 strated to the satisfaction of Florida shark fisher- 

 men that there were somewhat different require- 

 ments for bait depending on what species was 

 sought. It was also found that the increased cost 

 of very fresh bait, or bait frozen when fresh, was 

 fully justified by the improved catches. All of 

 the carcharhinid species of the Florida area, even 

 tliose frequently feeding on garbage, apparently 

 pi-efer fresh bait. The bait most universally ac- 

 cepted by all species was fresh fish and E. mil- 

 herti rarely was taken on any other bait. Some 

 species, notably EuJamia ohsciira and Galeocerdo, 

 took cut porpoise readily, and one species. Car- 

 cTi^rhiniis Jevras. occasionally j)referred pieces of 

 fresh sliark. Cut bait was found to be very much 

 better than the entire fish of any species. Prob- 

 ably the diffusioii of juices from cut bait was 

 greater than from fish in the round. 



In the Salerno, Fla., area the best catches were 

 obtained by sets made in the late afternoon with 

 pickup of the lines starting the following morn- 

 ing as soon as there was sufficient light to locate 

 the buoys. The freshness of the bait may have 

 had some bearing on the appai'ent better fishing 

 at dusk and during the early part of the night. 

 (Pitches made during the early morning and 

 throngliout the day were not infrequeiit, how- 

 ever, and it seems probable that the early part 

 of the night is merely a period of increased feed- 

 ing activity- for Evlfimia mUherfi. 



It is the c'onimon liabit of many .species of 

 sharks, including Eulamia milheiti. to nudge or 

 hit objects with their noses. I B.m^w<n\-Tift«*^ 

 t^t- they do this to test the object for juices. 

 The edible i|uiiiities of tiie oJjject are thus deter- 

 mined by the shark tiirough sensory cryi)ts which 

 are widely dispersed over the skin of the head 



