Clark, Smith, Kendall, and Fahay: 



Atlantic Coastal Fishes- -Data Report I 



attaching a 10 -pound (4 .5 -kg.) weight to the 

 sensor and bv moving the ship slowly into the 

 direction of drift with the ship's active -rudder 

 propeller. The salinometer was supplied with 

 a total of 50 meters (27 fm.) of cable which was 

 sufficient to measure salinities to the maximum 

 plankton sampling depth of 33 meters (18 fm .). 

 Surface isohalines for each cruise are shown in 

 Appendix figures Dl to D8 . Vertical isohalines 

 are shown for each transect of each cruise in 

 Appendix figures El to E25. Bottom isohalines 

 are not shown because salinity readings are not 

 available for the deeper parts of the shelf. 



The two Gulf V plankton nets were towed 

 simultaneously for 30 minutes at each station at 

 a constant engine speed, normally covering a 

 distance over the bottom of 2.5 nautical miles 

 (4 .8 km .) per tow . Direction of tow followed the 

 transect line except when strong head winds 

 necessitated altering the course to maintain 

 towing speed. With a mouth diameter of 40 cm . , 

 640 cubic meters of water would pass through 

 the Gulf V during a 30-minute tow, if a straining 

 efficiency of 100 percent is assumed. At the end 

 of each tow the nets were retrieved, washed 

 down and the plankton samples placed in quart 

 jars for preservation with 5 percent formalin 

 buffered with borax . 



In the oblique tow method used, each 

 Gulf V net was sampled for 5 minutes at six 

 3-meter (10-ft.) depth increments beginning at 

 the surface. The desired sampling depths were 

 determined by multiplying the amount of wire 

 out by the cosine of the wire angle . In water 

 depths of less than 33 meters the number of 

 steps was reduced for the deep net , and the 

 towing period was increased for the remainder 

 of the steps of the 30-minute tow. Where 

 depths were less than 18 meters we used only 

 the shallow net and where they were less than 

 15 meters, we reduced the number of steps as 

 we did for the deep net. Depths of the continen- 

 tal shelf along our transects were such that we 

 were able to sample from surface to bottom on 

 61 percent of the stations occupied. 



The Cobb mid-water trawl was towed for 

 30 minutes at a speed of 3 knots (5 .6 km. /hour) 



on a course reciporcal to that of the Gulf V tow . 

 Depth of towing was determined in the same 

 manner as for the Gulf V net. While towing the 

 trawl, we adjusted its depth to position it ver- 

 tically in layers where the ship's depth recorder 

 indicated concentrations of pelagic fish. 



It was not possible to use the trawl at all 

 stations because of weather and operational 

 difficulties . The trawl was not used during 

 cruise D-66-1 and was set at only three stations 

 during cruise D-66-3. The maximum number of 

 tows was made on cruise D-66-1 2 when 77 of the 

 92 regular stations were sampled. Station data, 

 including date, time, depth of water, depth range 

 of tow, and number of species captured, are 

 contained in Appendix table II for the 371 trawl 

 tows completed. 



Trawl collections were separated to 

 family or species immediately after capture. We 

 counted, measured, and preserved specimens in 

 appropriate concentrations of formalin ranging 

 from 5 to 20 percent. We weighed some of the 

 larger catches of stromateids and clupeoids and 

 drew random sub-samples for measurements. 

 The fishes captured are listed by cruise in 

 Appendix table III . Names are according to 

 Bailey, et al. (1960), except for the family 

 Monacanthidae where Berry and Vogele (1961) 

 are followed. 



Loran navigation was the principal 

 method used for positioning the Dolphin on 

 collecting stations . Increased accuracy was 

 obtained on inshore stations by use of radar, 

 land ranges, and by visual sightings of buoys and 

 lightships. Because of inherent limitations of 

 Loran navigation, accuracy of positioning the 

 Dolphin on offshore stations cannot be considered 

 better than +1.0 nautical mile (1 .8 km.). 



The order in which the transects and 

 stations were occupied varied from cruise to 

 cruise being dependent on weather and operational 

 factors (table 1). During our initial cruise 

 (D-65-4) we were not able to occupy stations on 

 transects A and B because of foul weather. 

 Similarly, on cruise D-66-1 we were forced to 

 cancel stations A -3 through A -7 because of foul 



