Abstract. —Analysis of restriction- 

 site polymorphisms of mtDNA and 

 Monte Carlo statistics were used to 

 test the hypothesis that at least two 

 genetic stocks of Spanish sardine 

 Sardinella aurita are present in the 

 eastern Gulf of Mexico, with one oc- 

 curring at each of the two main 

 fishery locations off Florida. Also in- 

 cluded for comparison were speci- 

 mens of Spanish sardine collected off 

 southern Brazil. No significant het- 

 erogeneity of mtDNA haplotype fre- 

 quencies was detected among speci- 

 mens from the two locations within 

 the Gulf of Mexico after analysis of 

 57 individuals (28 from Tampa Bay 

 and 29 from the Florida Panhandle) 

 using 9 informative restriction en- 

 zymes. However, highly-significant 

 differences were observed between 

 the specimens from the Gulf of 

 Mexico and 16 specimens from 

 southern Brazil. Based on counts of 

 gill rakers of all specimens from both 

 regions and the results of the 

 mtDNA analysis, it is suggested that 

 Sardinella brasiliensis, the Brazil- 

 ian sardine, is conspecific with S. 

 aurita, and that S. aurita is prob- 

 ably represented by genetically- 

 identifiable populations in the west- 

 ern North and South Atlantic. 



Differences in haplotype 

 frequencies of mtDNA of the 

 Spanish sardine Sardinella aurita 

 between specimens from the 

 eastern Gulf of Mexico and 

 southern Brazil 



Michael D. Tringali 



Department of Marine Science, University of South Florida 

 140 Seventh Avenue South. St Petersburg, Florida 33701 

 Present address. Florida Marine Research Institute 

 Department of Natural Resources 

 100 Eighth Avenue SE, St. Petersburg, Florida 33701-5095 



Raymond R. Wilson, Jr. 



Department of Marine Science, University of South Florida 

 140 Seventh Avenue South, St. Petersburg, Florida 33701 



Manuscript accepted 17 February 1993. 

 Fishery Bulletin. U.S. 91:362-370(1993). 



Spanish sardine Sardinella aurita 

 (Valenciennes) ranges in the western 

 Atlantic from Cape Cod, throughout 

 the Gulf of Mexico and Caribbean 

 Sea, to southern Brazil (Whitehead 

 1973). It is also present in the Medi- 

 terranean Sea and in the eastern At- 

 lantic off the African coast (Fisher 

 1978, Whitehead 1985). A second sar- 

 dine species, Sardinella brasiliensis 

 (Steindachner), reportedly occurs 

 within the range of S. aurita between 

 the Gulf of Mexico and southern Bra- 

 zil (Whitehead 1973 and 1985, John- 

 son & Vaught 1986), but there have 

 been no studies successful in fully 

 differentiating the two species within 

 the eastern Gulf of Mexico (Wilson & 

 Alberdi 1991). There has tradition- 

 ally been a small but important 

 baitfish fishery for Spanish sardine 

 off Florida with an annual landing 

 of over 1500 1 as recently as 1988. 

 However, this fishery closed abruptly 

 in 1989 after landings dropped 

 sharply between 1988 and 1989. The 

 closure was partly a response to un- 

 certainty about the number of spe- 

 cies or stocks being fished (Sutter & 

 Mahmoudi 1992). 



Management concerns about the 

 sardine fishery in the eastern Gulf of 

 Mexico involve the possibility of lo- 

 cal stock depletion or collapse from 

 increased fishing pressure at the two 

 primary fishing areas in the eastern 

 Gulf of Mexico, the Florida Pan- 

 handle and Tampa Bay. There is also 

 concern over the possibility of over- 

 fishing one of the two species sup- 

 posedly present. The first concern has 

 arisen from the observation that 

 Spanish sardines caught by the 

 fisheries operating at these two loca- 

 tions appear to consistently differ 

 morphometrically (Johnson & Vaught 

 1986), suggesting the possibility of 

 separate genetic stocks or species. In 

 response to these concerns, Wilson & 

 Alberdi (1991) electrophoretically 

 compared more than 300 specimens 

 from the two areas at 41 presump- 

 tive genetic loci and found no impor- 

 tant differences in allele frequencies, 

 nor any fixed differences. They con- 

 cluded that stock differences were 

 only weakly indicated, and that no 

 genetic evidence of two species of 

 Spanish sardine in the eastern Gulf 

 of Mexico had appeared. 



362 



