2 Michael Graham 



an appreciable effect on the benthos of the plaice area, the community within that 

 sanctuary should be appreciably different from the community outside. The sanctuaries 

 of two light vessels, the Haaks and the Terschelling, were examined with the following 

 gear : Petersen's grab ; Naturalist's dredge ; Agassiz trawl ; otter trawl with shrimp- 



Table I. — Dredging before and after trawling 



BEFORE 



George Bligh, Cruise K (1938), Sta. 16, 10th July, 1938, Naturalist's 

 dredge (6 foot) lined shrimp-netting, Egmont SE'ly 15 miles, Dhan on 90 

 fms. wire in Lat. 52° 44i' N. Long. 4° 16' E., 13 fathoms, sand, 1015 to 2010 

 hours, tides various, sea 4, wind SW'ly 4, sky cloudy, 14 hauls driving with 

 wind and tide except where otherwise noted. 



Dhan bearing and distance 



N to NxW \ mile (magnetic variation 9° W) 



S to SJE \ mile 



S 1} miles 



E to SE^E * mile 



W to SWxW * mile 



NE 200 yds. to \ mile (? direction reversed) 



NE X E to SxWiW i mile 



NExE i mile to ESE i mile 



NExE i mile to 200 yards 



NExE i mile '* tide getting less " 



NExE i mile to ENE i mile 



NExE to SW i mile 



NExE to SW \ mile " with help of engines " 



buoy to NE'ward no distance 



AFTER 



42 traverses with the trawl as nearly as possible to the tracks of Sta. 16, 

 Hauls 7-13; Cruise K 1938, Sta. 20, 13th July, 1938, otherwise as for Sta. 16 

 but time 1415 to 1920 hours, tide " 1400, BuflFs and Dhan NNW, so pro- 

 ceeded to buoy ", sea 2, wind variable 2, sky cloudy, 7 hauls driving with 

 wind and tide. 



Haul Time Dhan bearing and distance 



(assumed 10 

 mins. duration) 



1 1418-1428 NExN to ESE i mile 



2 1447-1505 NNE to Simile 



3 1524-1538 NExE to S i mile 



4 1599-1612 NExE to SiE i mile 

 6 no record — " foul haul " 



6 1 704- 1712 ENE 300 yards to SSW 200 yards 



7 1730-1745 NExE to SxE i mile 



8 1810-1826 ENE i mile to SSE 200 yards 



9 1 842-1900 " ? washed it all out " 



net cover on the codend. Control hauls were made 5 miles away from the Haaks only. 

 That work was done on the 6th, 7th, 8th and 9th of July, 1938. {George Bligh K 1938, 

 Stas. 2-10, 11-12, 13-14). 



Another sanctuary is provided by the under-water sand dunes of the extreme 

 south-eastern North Sea. These are dangerous to otter trawls, because of the trawl 

 doors getting down into the small valleys between the ridges and the net then fouling 



