6. During December to June the largest 

 concentrations of vessels were located 

 on the eastern and southern portions of 

 the grounds. During the summer, the 

 fleet was more widespread. 



LITERATURE CITED 



BULLIS, HARVEY R. 



1951. Gulf of Mexico shrimp trawl 

 designs. U. S. Fish and Wildlife 

 Service, Fishery Leaflet No. 394, 

 16 pp. 



GRAHAM, M. (Editor). 



1956. Sea fisheries, their investi- 

 gation in the United Kingdom. 

 Edward Arnold, London, 487 

 pp. 



KNAKE, BORIS O., JAMES F.MURDOCK, 



AND JAMES P. GATING. 



1958. Double -rig shrimp trawling in 



the Gulf of Mexico. U. S. Fish 



and Wildlife Service, Fishery 



Leaflet No. 470, 11 pp. 



MEDICO, ERNEST J. 



1958. Certification and after-use 

 measurement of manila otter-trawl 

 cod ends. U. S. Fish and Wildlife 

 Service, Commercial Fisheries 

 Review, vol. 20, No. 12, pp. 1-8. 



REGAN, JAMES, C. P. IDYLL, AND E. S. 

 rVERSEN. 

 1957. Mesh size regulations as a pos- 

 sible method of managing the Tor- 

 tugas shrimp fishery. Proceedings 

 of the Gulf and Caribbean Fisheries 

 Institute, Ninth Annual Session, 

 November 1956, pp. 18-22. 



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