FISHERY BULLETIN: VOL. 74, NO. 1 



square mesh body and a Vs-inch (0.3-cm) square 

 mesh cod end Hner. 



The study area extended along the northeast- 

 ern Gulf of Mexico from east of the Mississippi 

 River Passes, La., to the w^estern edge of Apala- 

 chee Bay, Fla., over a depth range of 20 to 190 m 

 (Figure 1). The easternmost stations (between 

 long. 84°37'W and 85°30'W) were visited, with 

 few exceptions, in October and December 1970, 

 and January, April, May, July, August, and 

 September 1971. The remaining stations were 

 visited only once during cruises conducted in one 

 of the following months: July, October, and De- 

 cember 1969; October and November 1970; Janu- 

 ary, February, April, July, and October 1971. 

 Station locations were determined through loran. 

 Station depth was recorded from fathometer 

 readings. Depths for a few stations were extrapo- 

 lated from soundings recorded for that location 

 on "1100 Series" U.S. Coast and Geodetic Survey 

 maps. (For complete station data and specimens 

 examined see Lewis 1973.) The principal investi- 

 gators of the Gulf Shelf Project determined the 

 sampling regime for each station. One trawl 

 sample was taken at each station. Trawling time 

 on the bottom ranged from 10 to 60 min. The time 

 duration for the majority of trawls at shallow 

 stations (i.e. less than 90 m) was 10 min; for the 

 deeper stations, 20 min. In order to standardize 

 these trawling efforts, catches were recorded as 

 number of fish collected per 10 min trawling 



(catch per unit effort), and transformed [Y - log 

 {X + 1)] for analysis of the variance. Data for all 

 stations (when available) were used for analysis 

 regardless of whether or not the particular spe- 

 cies was present. 



Bottom temperature was recorded for most 

 stations by bathythermograph and on a few 

 occasions either by expendable bathythermo- 

 graph or reversing thermometers. Bottom type 

 was determined by examination of samples taken 

 in a bucket dredge dragged over the trawl area. 

 Bottom type was divided into two major classes; 

 coarse sand overlain with shell hash (type I), and 

 fine sandy silt, clay, or mud (type ID. Data for 

 bottom type were not collected at some stations 

 and consequently fishes taken at these stations 

 were not used in analysis of bottom type. Night 

 was considered to be that interval of time be- 

 tween 1 h after sunset and 1 h before sunrise at 

 that time of the year, while day was considered to 

 be between 1 h after sunrise and 1 h before 

 sunset. Fish collected at dawn or dusk were not 

 used in the analysis of time of capture data. 



The standard length (SL) of each fish was 

 measured to the nearest millimeter. Identifica- 

 tions were made following Ginsburg (1950), 

 Miller (1965), and Miller and Kent (1971). Speci- 

 mens were preserved in 10% Formalin^ origi- 



^Reference to trade names does not imply endorsement by 

 the National Marine Fisheries Service, NOAA. 



Figure l.— Map of the study area sampled by the RV Tursiops and USNS Lynch between July 1969 and October 1971. 



94 



