THE SYSTEMATIC STATUS OF MERLUCCIUS IN THE 

 TROPICAL WESTERN ATLANTIC OCEAN INCLUDING 



THE GULF OF MEXICO 



Charles Karnella' 



ABSTRACT 



Several morphometric and meristic characters are used to compare populations of 

 Merluccius from the Gulf of Mexico and Atlantic Ocean. Both populations are shown 

 to have similar values for all characters studied. As a result M. magnoculus Ginsburg 

 is relegated to the synonymy of M. albidus (Mitchill). 



Geog^raphical variation is noted in many of the characters investigated. 



The widely distributed gadoid fish genus Mer- 

 luccius contains an indeterminate number of 

 commercially fished species. There are 11 nom- 

 inal species (Grinols and Tillman, 1970), known 

 variously in the United States as either whiting 

 or hake. The object of this paper is to deter- 

 mine the number of species living in the tropical 

 western Atlantic (including the Gulf of Mexico 

 and Caribbean). Ginsburg (1954) recognized 

 three species from the western North Atlantic. 

 One of these, M. hilinearis (Mitchill), is distinct 

 from the other two nominal forms in having 

 more gill rakers on the first arch (15-22 vs. 

 9-12). This species will not be considered 

 further as it does not occur south of Cape Fear, 

 N.C. M. magnoculus Ginsburg was described as 

 new mainly on the basis of its having a longer 

 head and shorter paired fins than its closest rel- 

 ative, M. albidus (Mitchill) . M. albidus is found 

 in the tropical western Atlantic, although not 

 exclusively so, as it is known to occur sympatric- 

 ally with M. bilinearis in the north. Ginsburg 

 further noted that M. magnoculus and M. albidus 

 were also moderately to slightly divergent in the 

 following characters: maxillary length, snout 



' Formerly National Systematica Laboratory, National 

 Marine Fisheries Service, NOAA ; present address : Di- 

 vision of Fishes, U.S. National Museum, Washington, 

 DC 20560, and Department of Biological Sciences, George 

 Washington University, Washington, DC 20006. 



M»nu5cript accepted July 1972. 



FISHERY BULLETIN: VOL. 71, NO. 1, 1973. 



length, eye diameter, and number of first dorsal, 

 second dorsal, pectoral, and anal fin rays. More- 

 over, M. magnoculus was confined to the Gulf 

 of Mexico while M. albidus occurred off the east- 

 ern coast of North America from Georges Bank 

 to the Tortugas off the west coast of Florida. 

 The lack of comparative material of equivalent 

 size from the Gulf, the doubtful systematic status 

 of two specimens from Savannah, Ga., and of a 

 single specimen from off Cape Canaveral, Fla., 

 make uncertain Ginsburg's tentative assignation 

 of these specimens to M. albidus. Difficulty in 

 identifying subsequent material from the Gulf 

 of Mexico and Caribbean has necessitated a re- 

 assessment of the taxonomic status of M. albidus 

 and M. magnoculus, especially since the stated 

 differences between the two are slight and there 

 is at least some overlap in all characters used to 

 separate them. 



Throughout the body of this paper the At- 

 lantic population is taken to include specimens 

 from the Caribbean also. 



MATERIAL 



A total of 253 specimens was examined; 86 

 from the Gulf of Mexico and 167 from along the 

 eastern coast of the Americas, lat 41*'30'N south 

 to lat 7°26'N (Figure 1). This total included 

 Ginsburg's material whenever possible. How- 



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