GULF OF MEXICO COMMERCIAL SHRIMP POPULATIONS 



347 



from a boom located amidship and projecting aft, 

 most offshore trawlers are currently etiuipped to 

 tow two smaller trawls from booms projecting 

 laterally. Today, the greatest number of single- 

 rigged vessels will be found in the inshore fleet; 

 the capacity to pull two trawls being more or less 

 restricted to larger vessels. Practically all sea- 

 going trawlers constructed since 1958 are double 

 rigged. 



Ajnong offshore fishermen there is unanimity 

 of opinion that two sets of small gear are generally 

 easier to handle than a single large gear. Althougli 

 reducing vessel maneuverability to some extent, 

 they increase speed and range of fishing operations, 

 and lend stability to the vessel when trawling. 

 Some disagreement prevails, however, as to the 



relative catching ability of two small trawls 

 contrasted to that of one large trawl. It would 

 appear that in some circumstances, disadvantages 

 inherent in one arrangement might offset ad- 

 vantages in the other, resulting in a comparable 

 efficiency from a production standpoint. Knake, 

 Murdock, and Cating (1958) give a comprehensive 

 re\'iew of double-rig design and operation. 



For the most part, Gulf of Mexico shrimp 

 trawls are quite uniform in shape and dimension. 

 Single- and double-rig trawls arc usually "flat" in 

 design, "balloon" types being in tiie minority. 

 In offshore trawling gear, cod-end mesh dimen- 

 sions are more or less fixed at 2 or 2^4 inches 

 stretch measure although shrinkage may reduce 

 the average mesh size of individual nets to as 



Figure .3. — Gulf shrimp trawler of earlier design used in nearshorc and inshore fishing operations. (This vessel was con- 

 structed in 1943, is in the 40-ft. class, and is single-rigged.) 

 643091 O— 62 2 



