The Spawning Areas of Sand-Eels in the North Sea. 11 
observations which have been made within the northern portion of 
this area show that the larvee are but sparingly represented over the 
shallow coastal grounds of the Lewis; but over the somewhat deeper 
grounds off the Sutherland coast the conditions must be much more 
favourable, as the larvee are found in the plankton in large numbers. 
The averages obtained here are as follows : — 
Vertical Horizontal Hauls, half-hour duration. 
Locality. Haul. Surface. Mid-water. Bottom. 
Lewis, ‘ : i! 2 20 
Sutherland, . : 39 809 769 812 
Attention has, so far, been mainly directed to the various 
localities where the larval sand-eels have been found during the first 
quarter of the year. ‘These areas are by no means co-extensive with 
the total area investigated. As a glance at the chart shows, there 
are certain regions to the north and east of Shetland and in the 
centre of the North Sea where larval sand-eels are very poorly 
represented or are entirely absent. 
Owing to the outlying position of the area north of the 
100-fathom line this locality has not been regularly examined 
throughout the first quarter of the year, but the fact that no larval 
sand-eels were found there even in the month of March, taken in 
conjunction with their absence at intermediate localities, Station 
124 (Lat. 61° 18’ N., Long. 1° 35’ W.) and Station 12 (Lat. 
61° 03’ N., Long. 0° 34’ W.), in the month of February is 
strongly presumptive evidence that they do not occur in the plankton 
of the deeper waters in the earlier months of the year. Larval 
sand-eels were found, however, in March in small numbers at 
Station 12, which lies immediately over the steep gradient beyond 
the 50-fathom line towards the deep Norwegian Sea. Here we 
probably approach the northern limit of the spawning area. 
That large area under 100 fathoms in depth which lies north of 
Scotland and west of the Orkney and Shetland Islands has still to 
be adequately explored. We have no positive evidence that there 
is here a spawning area for sand-eels. The facts already stated (1) 
that larval sand-eels are found in numbers in the Minch, (2) that 
they occur in very large numbers at Dunnet Head and the Fair Isle, 
and (3) that beyond the northern entrance to Yell Sound, in 
Shetland, there is a considerable rise in the frequency of the larval 
forms, strongly suggest that the shallower portions at least of this 
vast region constitute an important spawning area. ‘The role 
which this area may play in the ultimate distribution of the sand-eel 
can be appreciated when it is stated that in the later months of the 
year larger larval forms of sand-eels are often found in the upper 
water layers of the depths of the Faeroe-Shetland Channel and the 
deep area to the north of Shetland. 
The northern region of the North Sea which lies to the east of 
Shetland is very poorly populated with larval sand-eels in the first 
quarter of the year. This region of somewhat uniform conditions 
of depth and character of bottom is of considerable extent; towards 
the north the depth gradually increases from an average of about 
70 fathoms, and finally ends on the edge of the Continental plateau 
in a depth of over 100 fathoms, whilst to the east it ends abruptly 
