The sampler is then assembled and is ready for the next 

 towing operation. The after meter remains in the unit at all times. 



Discussion 



The Model Gulf III plankton sampler has been used for only a 

 limited number of tows so final judgment will be reserved until 

 adequate testing has been corapleted© At this time, however, it can 

 be said that the sampler indicates good possibilitieso Specimen 

 condition is good and compares favorably with silk net collections 

 at slower speeds. The sampler tows very well, with the aid of the 

 liO-pound depressor, at speeds to 6 knots. The wire cloth used 

 (50 mesh x #0075") duplicates very nearly No. 1 silk mesh. Coarser 

 meshes woiild xmdoubtedly improve the effectiveness with the larger 

 marine forms. Performance at higher speeds and with a variety of 

 meshes will be studied in the near future. 



Figures 7 and 8 illustrate the construction of the Gulf Model III 

 plankton sampler. The line drawings describe the suspension of the 

 Atlas current meter in the forward end of the plankton sampler and 

 illustrate the orientation of the net and bucket with respect to the 

 housing and the current meter » 



Preliminary examination of samples taken reveal several deep 

 sea forms not previously recorded in our silk net tows. Tentatively 

 identified are these: Diplophos 7,0 c«,, ii,5 cm,, 3.9 cm., and 

 Stomias 5*3 cm. Several squid were taken, the largest being U cm, 

 in overall length. No squid have been recorded from our previous 

 silk net samples. 



The chief disadvantages of the sampler are: initial high cost, 

 and because of the large size, awkwardness for handling the unit in 

 rouph weather. Though the initial cost is high it should outlast 

 many silk nets because of its construction and non-deteriorating 

 materials. Handling diffic\ilties can be overcome with adequate gear, 

 A special cradle on the ship deck provides safe, s6ciire storage. 



Construction and Operation Advantages 

 of the Model Gulf III Plankton Sampler 

 over the Conventional It-meter Silk Net 



Conventional ^.eter Silk Net Model Gulf III Plankton Sampler 



1, Net tears when towed at high 1, Wire cloth net will not tear when 

 speeds, the sampler is towed at high 



speeds. 



2, Many of the more agile fonms 2. At high speeds possible with the 

 evade the net when it is towed metal sampler some of the more 

 at slow speeds, agile forms may conceivably be 



captured* 



11 



