38 SUMMEE PLANKTON FKOM WEST OOAST OE SCOTLAND AND IRISH SEA, 



of zoo-plankton in the lochs on the mainland ; but our hauls being vertical 

 from the bottom at great dej)ths probably sampled a much larger body o£ 

 phyto-plankton, and included some species that did not appear at the surface. 

 It may be added that Prof. P. T. Cleve gave a short account, in the 

 Scottish Fishery Board's Report for 1896, {>. 297, of the phyto-plankton of 

 the ' Research ' collections made in the Shetlands, and showed that the 

 stations on the western side were rich in Diatoms, while the hauls taken 

 from the east of the islands were much poorer — this, again, showing a difference 

 between not very distant localities at the same time of year. 



The Scottish Fishery Board do not seem to have published any further 

 investigations in regard to plankton in their western seas ; nor does the 

 Irish Fishery Department give any information in regard to the minuter 

 plankton of the seas between Scotland and Ireland : apparently only coarse- 

 meshed nets have been used by the Irish investigators, and no Diatoms 

 are given in the published tables (Conseil Per. Internat., Bull. Trimestriel, 

 1907-8, Copenhague, 1909), which deal with zoo-plankton alone. Finally, 

 the map giving the stations in European seas at which ])lankton observations 

 have been taken in recent years {loc. cit., Resume Planktonique, Introduction, 

 p. xii, 1910) shows a great gap extending from near Cape Wrath, in the 

 north of Scotland, to Belfast Lough in Ireland. The whole of the seas around 

 the Western Islands of Scotland, like the western coasts of England 

 and Wales, have apparently been omitted from the Official Ijiternationa' 

 investigation. 



This is, from the scientific point of view, most unfortunate, as, for a 

 complete understanding of the plankton changes throughout the year, in the 

 Irish Sea at least, it would be useful, and may be essential, to have 

 information as to the planktonic conditions month by month on the north 

 coast of Ireland and on the west coast of Scotland. 



The unofficial observations recorded in this paper have shown that, 

 while the abundant vernal phyto-plankton dies away in the Irish Sea in 

 early summer, a similar micro-flora is present in quantity in some parts 

 of the sea on the west of Scotland (e.r/., the Sound of Mull, and the sea 

 round Canna, Eigg, &c.) until July, and possibly latter. It can scarcely be 

 doubted that the phyto-plankton maximum is found in spring in the Hebrides 

 as in the Irish Sea. But have the July Diatoms remained since April, or 

 did they die ofF (as they do further south) and then re-appear ? If the 

 latter, have they come from the Atlantic or from northern seas ? Do they 

 continue to be abundant throughout the remainder of summer and autumn ? 

 Are any of them left in the deeper channels in winter? These and many 

 other problems press for solution, and will probably only be solved by 

 contniuous plankton work throughout the year at a series of stations along 

 our western coasts. 



