drained The sides of the tubes were washed 

 down with water, and then the silk disks and 

 sample were removed and placed in a small vial 

 of preservative without attempting to separate 

 the captured organisms from the silk . The 

 labels placed in the tubes carried the date, run 

 number, and hour. These data were sufficient 

 to locate the sample on the vessel's cruise 

 track. New silk disks were placed in the filter 

 assemblies, and the apparatus started again . 



Remarks 



The sampler described is not an ideal 

 apparatus for quantitative plankton sampling, 

 but it does supply us with a record of the gener- 

 al distribution of some of the larger plankton 

 organisms of the Gulf of Mexico which we would 

 not have otherwise obtained. Its advantages are 

 that it collects continuously regardless of sea 

 conditions, it is simple to operate, and the 

 water flow through the apparatus is metered 

 directly. Table 1 represents an hourly break- 

 down of a typical run . 



The disadvantages are: Samples can be 

 taken from only one depth; turbulence and other 

 influences from the ship's hull have an unknown 

 effect on quantitative collection; clogging might 

 give trouble in more fertile waters heavily 

 laden with plankton; the turbulence of the pump 

 probably destroys or mutilates more fragile 

 organisms although there was no evidence of 

 excessive damage; the filtering rate is limited 

 by the maximum hydrostatic head available in 

 the tubes, hence the mesh of the silk and the 

 flow is limited by the practical lengths of these 

 tubes. 



By way of comparison, it is illuminating 

 to plot some results from the G-II along with 

 some from the G-IA high-speed sampler. The 

 latter was described by Arnold and Gehringer 

 (1952) . It was towed between hydrographic 

 stations without removal from the water and 

 was provided with a meter for measuring water 

 filtered. 



For comparison, the hourly values from 

 the G-11 data which corresponded to a given 

 G-IA tow were selected and accumulated (fig. 7) . 



As has been pointed out, the G-II sampled con- 

 stantly at approximately 10 feet below the 

 surface as contrasted to a sampling depth of 3 

 to 20 meters for the G-IA. This factor alone 

 makes comparisons of the 2 sets of data invalid, 

 but with the extreme differences in design and 

 operation of the two Kinds of apparatus in mind 

 the general parallelism of the 2 sets of data is 

 striking. 



1 would like to suggest that the internal 

 mechanism of the Hardy Continuous Plankton 

 Recorder could be adapted to inboard use and 

 would be superior to, although more complex 

 than the apparatus described here. Such an 

 arrangement operating continuously would con- 

 tribute much to our knowledge of the relation of 

 plankton aggregates to the congregation of fishes. 



LITERATURE CITED 



Arnold, E. L., Jr. 



1952. A high speed plankton 



sampler (Model Gulf I-A) . U.S. 

 Fish and Wildlife Serv., Sp. Sci. 

 Rept. 88, pp. 1-6. 



Gehringer, J. W. 



1952. An all-metal plankton 



sampler (Model Gulf III) . U.S. 

 Fish and Wildlife Serv., Sp. Sci. 

 Rept. 88, pp. 7-12. 



Hardy, A. C. 



1939. Ecological investigations 

 with the continuous plankton 

 recorder: Object, plan and 

 methods . Hull Bull . of Mar . Ecol . 

 Ul):l-57. 



Lucas, C. E. 



1940. Ecological investigations 

 with the continuous plankton 

 recorder: The phytoplankton in 

 the southern North Sea, 1932-37. 

 Hull Bull, of Mar. Ecol. J_(3): 

 73-170. 



