A Preliminary Report Of The Zooplankton Collected Aboard 

 USCGC Westwind During September 1968 



W. G. TiDMARSH 1 



INTRODUCTION 



As part of the oceanographic program con- 

 ducted aboard tlie USCGC WESTWIND in the 

 Xortli Water region of Baffin Bay during Sep- 

 tember 1968, a total of 16 biological stations were 

 occupied (fig. 1). The purpose of the biological 

 program was to gain more knowledge of the ver- 

 tical and horizontal distribution of the various 

 zooplankton populations in the North Water 

 area. In conjunction with the physical data ob- 

 tained, it is hoped to relate the presence of several 

 species found in the region to specific water 

 masses. The present study concentrates on the 

 copepod and chaetognath populations, but a 

 more comprehensive study of other planktonic 

 forms will be undertaken at a later date. This 

 program is part of a study of the biology of the 

 waters influencing the North Water. Data will be 

 combined with that obtained in future programs 

 to prepare a general survey of the planktonic 

 zoogeography of the North Water region. 



PROCEDURES 



Thirty-one collections were made at 16 stations 

 between September 8 and September 23, 1968 in 

 the general vicinity of the Carey Islands in north- 

 ern Baffin Bay. Plankton collections were made 

 from the WESTWIND using one metre stramin 

 nets and one-half metre #6 mesh and one-quarter 

 metre #20 mesh nylon nets shackled to a 5/32 

 inch stainless steel wire running from the main 

 hydrographic winch. All tows were made with 

 non-closing nets and no flow meters were used. 

 For vertical tows, depending upon the size of 

 the net, weights between fifteen and thirty 

 pounds were attached to the caud end of the net 

 immediately below the collecting bucket. A small 

 depressor was used for the horizontal tows. 



Collections varied between 10 metres and 400 



' Marine Science Center, McGill University, Montreal, 

 Canada. 



metres in depth, with the majority being made at 

 50 metres, 80 metres, 150 metres and 274 metres. 

 Tows were made after consulting the physical 

 data to determine the depth of the thermocline 

 in order to sample in the different temperature 

 layers present. Discreet sampling in each layer 

 was not possible because the nets were of the non- 

 closing variety. Of the 31 tows attempted, 27 

 were vertical or oblique and 4 were horizontal. 

 Poor results were obtained in two horizontal tows 

 due to difficulties in streaming the stramin nets. 

 Tows in all cases were conducted from the hydro- 

 graphic winch platform; however in making 

 horizontal tows the starboard boat crane was 

 swung outboard, with block attached, to carry 

 the net and wire well clear of the propellers. 

 Vertical tows were made at a speed of 1 metre 

 per second. Wire angles encountered were com- 

 pensated for to allow sampling at specific depths. 

 Horizontal collections were nuide at a speed of 

 2 knots for 15 minutes along a straight line. 



No analysis or sorting was carried out on 

 board, though relative abundances of plankton 

 were generally noted. Specimens were preserved 

 in a 5% formaldehyde solution in 8 oz. and 16 oz. 

 plastic bottles. The specimens were in excellent 

 condition on arrival at McGill University where 

 the sorting, identification and counting of sam- 

 ples began immediately. 



RESULTS 



A preliminary plankton analysis concentrating 

 on copepod and chaetognath populations has been 

 completed and shows some interesting trends 

 which will require further field work in the re- 

 gion to substantiate. The Copepod populations 

 were either Atlantic or Arctic forms. No Pacific 

 forms were found in any of the collections taken. 

 Three calanoid capepods Cala.nus hyperhoreus, 

 f'alanus glacialis and Metridia longa dominate 

 the collections with Pseudocolanus minutu.% Mi- 

 crocalanus pygmaeus and the cyclopoid copepod. 



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