FISHERY BULLETIN: VOL. 85, NO. 1 



Figure 1.— Collection locations and numbers of tows per location in the eastern Gulf of Mexico. Sampling regions: NE - northeast; 

 EC - eastern central; SE - southeast. Circle in EC region delimits 20 nmi diameter sampling area around lat. 27°N, long. 86°W. 



eastern Gulf, and although there is a large discrep- 

 ancy in the relative number of samples taken and 

 in day-night depth coverage, collections were 

 assigned to three latitudinal areas: northeast (NE), 

 eastern central (EC), and southeastern (SE). The 

 northernmost Gulf is known to support populations 

 of cooler water myctophid species (Backus et al. 

 1977), and our hydrographic data showed that the 

 southeastern stations were the only collections that 

 were directly impacted by the tropical Loop Current 

 waters during sampling, hence this regional parti- 

 tioning. 



Most of the cruises were made during the sum- 

 mer months (June through early September), and 

 although sampling extended from late March 



through early October, all cruises were made while 

 summer hydrographic conditions prevailed in the 

 study area. With respect to lunar cycles, 9 of the 

 12 cruises occurred during waxing or full moon 

 period, 2 during first quarter, and 1 during new 

 moon. Table 1 lists general data for the 12 cruises. 

 Samples were taken primarily in the upper 1,000 

 m of the water column, although a few extended as 

 deep as 1,500 m. The nets used were 3.2 m^ or 6.5 

 m- mouth area opening-closing modified Tucker 

 trawls (Hopkins et al. 1973) which incorporated 1.1 

 cm stretch mesh in the body and 505 ^ mesh in the 

 cod end. Opening and closing of the nets were 

 accomplished mechanically using double release 

 mechanisms and messengers. Fishing depth was 



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