Sea-Currents and the Distribution of Plaice. 49 



how the bottom currents on the East Coast of Scotland divides in the 

 region of the " Long Forties," and how one branch takes a south- 

 westerly set towards the Firth of Forth. This branch again divides 

 off Fife Ness, and in addition to the set into St. Andrews Bay a deep 

 current flows northwards, across the Tay and up the Scottish Coast as 

 far as Johnshaven. There is, of course, as has been stated, a close 

 connection between sm'face and bottom currents, and the stranding 

 of surface bottles on the East Coast of Scotland would seem to show 

 that the configm'ation of the coast and sea-bottom south of Buchan 

 Ness modifies the general direction of flow of the western periphery of 

 the south-going ciurrent. 



We have seen that spawning on the East Coast of Scotland is 

 somewhat sharply restricted in an easterly direction, and that the chief 

 spawning grounds lie in a narrow belt not more than twenty miles 

 from the coast, stretching from Montrose to Aberdeen. This zone 

 is sandwiched in between the main south flowing current and the 

 north-flowing branch from Fife Ness, so that eggs spawned in an area 

 so situated are thus less liable to be drifted extreme distances sea- 

 wards or southwards. No doubt most of the eggs which are carried 

 eastwards along the south shore of the Moray Firth are found ulti- 

 mately on the sandy shallows southwards from Buchan Ness. Now 

 it has been shown that the maximum catch of small plaice in any 

 area in the North Sea frequented by Aberdeen trawlers was in 

 statistical area XXIII. , and area XXVIII. has the highest mean 

 density of small plaice on the Scottish Coast. In all probability therefore 

 the supply of small plaice on the East Coast of Scotland within these 

 statistical areas is maintained not only from adjacent spawning ground 

 but also from spawning grounds in the Moray Firth, east of Lossiemouth. 



The annexed chart illustrates, in a summary way, many of the 

 points already set forth regarding the distribution of the pelagic eggs 

 of the plaice in the early months of the year and its relations to the 

 general distribution of plaice classified as " large " and " small " 

 in the market statistics. The limits of distribution of large plaice, 

 that is, those plaice which have reached spawning age, agree very 

 closely with the bathymetric contour line of 50 fathoms, and the area 

 within which the pelagic eggs of the plaice have been found is co- 

 extensive with the area of distribution of these adult fish. All ob- 

 servations made to the east of this line have given negative results, 

 whilst at most of the localities within the shallower area positive 

 records have been obtained on some occasion. One exception may 

 be made to this general statement, as it is probable that a very small 

 number of plaice may spawn in the neighbourhood of the Bergen 

 Bank (59° 55' N., 2° E.). I am indebted to Mr. George Robertson, 

 Captain of the S.T. " Ortes," for this information. On the 28th 

 April 1914 he brought to Aberdeen market three female plaice which 

 he had captured in the locality. Two of these were spent fish in very 

 poor condition, but the third was fully ripe with running spawn, a 

 sample of which was kept. This information confirms a " Gold- 

 seeker " record which I had long looked upon as an anomalous one. 

 On 15th March 1908 a plaice egg in the " y " stage of development 

 was captured in the plankton at Station 7B (60° 35' N., 1° 50' E.). 

 This is the solitary record obtained by the " Goldseeker " from the 

 large deep area east of the fifty fathom line, but when taken in con- 



