and the remainder unballasted. Positions of 

 bottle releases and recoveries have been pub- 

 lished by Bumpus and Day (1957). Every 12 

 hours, the ship was stopped, a fix taken, and 

 both recorders checked. The highest number 

 appearing on the gauze in the tunnel was noted, 

 and the gauze wound manually to the next divi- 

 sion. At this time, a surface tow was taken with 

 a 1-meter net. Every 48 hours, the gauze roll 

 was removed, a new one loaded, and the paired 

 towing straps replaced. Torsional fatigue rapidly 

 reduced the breaking stress of the towing wire 

 and paired straps and necessitated the pre- 

 cautions outlined. Details and specifications of 

 the silk, wire rope, and so on, and methods of 

 loading and handling the recorders can be 

 obtained from the Oceanographic Laboratory, 

 Scottish Marine Biological Association, Edin- 

 burgh, Scotland. Every 96 hours, 2 fathoms 

 were cut from the outboard end of the towing 

 cable, and the thinnble replaced. After 8 days, 

 the towing wires were turned end for end on 

 the winch. At the end of 16 days, the towing 

 wires were replaced. 



Operation of the Hardy Plankton Recorder 



One recorder was towed at the surface and 

 one at 10 meters. A l/2-inch square nosepiece 

 was used, and the propeller pitch was set for a 

 gauze rate of roughly 2 inches per 5 miles of 

 tow at an average towing speed of 1 knots. The 

 gauze (60 meshes per inch silk) was made in 

 100 2-inch sections, allowing continuous towing 



for 500 miles without reloading. The time neces- 

 sary to haul the recorders, advance or change 

 the gauzes, take a 1-meter net haul, and reset 

 the recorders seldom exceeded l/2 hour. 



One-Meter Net Tows 



Qualitative samples of fish eggs and larvae 

 for hatching and identification purposes were 

 obtained by a 1-nneter net (No. silk) towed on 

 the surface (see figs. 1, 2, and 3) for 10-15 

 minutes at the slowest possible speed. The 

 spawning seasons and size ranges of the eggs 

 of haddock (M elanogrammus aeglefinus), cod (Gadus 

 morhua), and witch flounder (Glyptoce phalus cynoglosnus) 

 overlap. A few days before hatching, however, 

 the pigment pattern characteristic of the larva 

 appears, and the eggs of the three species can 

 then be distinguished. A portion of the fish eggs 

 was immediately separated from the other 

 plankton and transferred to hatching jars placed 

 in a constant-temperature bath maintained at 

 approximately 8° C. The remainder of the eggs, 

 all larval fish, and a representative sample of 

 other plankton were preserved in 5-percent 

 formalin. 



The water in the hatching jars was changed 

 once daily. The eggs were stirred and the 

 temperature recorded three times a day. After 

 the majority of the eggs had hatched, or reached 

 a stage of development where they were readily 

 identifiable, they were preserved in separate 

 vials in 5-percent formalin. 



Figure l,--Distribution of surface salinity and positions of 1-meter net tows, Albauoss III cruise 

 no. 46. March 19 to April 2, 1953. 



