114: Part III. — Seventeenth Annual Report 



states of the tide and during strong winds. At Station II. in February 

 one specimen of Nyctiphanes and sixteen examples of Euchaita were 

 taken in the surface net, and five Euchaita in the vertical net ; on Station 

 IV. in the same month the vertical net furnished one Nyctiphanes. In 

 March on Station II. one Nyctiphanes was found in the surface net, and 

 three examples in the one-fathom net. A number of young Nyctiphanes 

 were taken at the surface on Station II. in July, and in the vertical net 

 on Station I. one Euchaita was obtained. In February at Stations II. 

 and IV. when the examinations were made the tide was at half-ebb, and 

 the wind was N.W., force 3, and S.W., force 4, respectively. In March 

 at Station II. the tide was again at half -ebb, and the wind, which was 

 W., was of force 5. At Station II. in July the wind was westerly and 

 light; the tide, 1 bour flood, 



A chart has been prepared giving the curves formed by the volumes of 

 Copepods, etc., taken in the horizontal nets during the period of eight 

 months (Plate IV., B). A separate curve has been made for each station. 

 The vertical axis is divided into centimetres, each of which represents a 

 volume of lOOcc. of Copepoda, etc. The curves are distinguished from 

 one another by the different colour and character of their lines ; in 

 addition, the curve is labelled throughout with the number of the station 

 to which it refers. In C (ib.) is given the curve for the total volume of 

 Copepoda obtained each month. It is fairly regular, though rising 

 abruptly in April. In January, February, and March the Copepoda 

 remained fairly constant in quantity. During March, as will be seen from 

 reference to Table VI., there were large quantities of pelagic Crustacean 

 — probably Copepod — eggs in the waters of Loch Fyne, but they were 

 confined mainly to Stations I., II., and IV. In the following month the 

 numbers of Copepoda increased enormously, and from reference to Chart 

 B it will be seen that the increase took place mainly on Stations III. and 

 IV., although all of the stations show very great increments. The 

 increase is due to reproduction — which in the group of Copepoda appears 

 to be extremely rapid — and the collections are almost entirely composed 

 of young Copepods of all stages ; so far as can be roughly judged, the 

 form most abundant is Calanus jinmarchichus. Calderwood * referred to 

 the " appearance of Copepods in greater and greater numbers until, when 

 the herring fishing is at its height, the Copepods are in vast abundance. 

 At this season the prevailing species is Calanus finmarchicus, which 

 occurs in sufficient numbers in certain places to colour the surface of the 

 water. It is the species which serves as the principal food of the Loch 

 Fyne herring during the summer." Murray t also records the occurrence 

 of vast numbers of crustacean, fish, and other eggs coincident with the 

 appearance of immense floating banks of diatoms between the end of 

 January and the first of May. In April the temperature of the water at 

 Stations III. and IV. was higher than at Station I., and that may to some 

 extent account for the fact that the Copepoda at the former stations 

 reproduced their species so much more rapidly than at Station I. In 

 May, while the total volume of Copepoda remained the same as in April, 

 great change had taken place at the different stations. The quantities on 

 Stations I., II., and V. had steadily risen, while Station III. showed 

 a fair decrease, and Station IV. a decrease almost as rapid and extensive 

 as its former rise. The depletion of Station IV. may be in part due to 

 drift, but if that were so, the same drift which robbed Station IV. ought 

 to re-supply it from Station V. In May, then, the main mass of the 

 Copeopoda was further down the loch than in the previous month. 



* Calderwood — "Notes on the Copepods of Loch Fyne," Fourth Annual Report of the 

 Fisheiy Board for Scotland, p. 147. 

 t Op. ext. 



