of the Fishery Board for Scotland. 



79 



II. ON THE PELAGIC FISH-EGGS AND LARVAE OF 

 LOCH FYNE. 



By H. Chas. Williamson, M.A., B.Sc. (Plates II-VI.) 



Towards the end of the year 1897 I was instructed to determine, as far 

 as possible, the approximate number of pelagic eggs and larvae in Loch 

 Fyne. The name Loch Fyne is used to designate that portion of the 

 Clyde area extending from Ardlamont Point to Cairndow, and it is 

 conveniently divided by Otter Spit into Lower and Upper Loch Fyne. 

 Mill* refers Lower Loch Fyne to the Arran basin, and Upper Loch Fyne, 

 cut off, as it is, from the lower portion by the shallow barrier at Otter, 

 he considers a distinct area. 



" Loch Fynef runs, on the whole, north-eastward for 26 miles, following 

 " the slight curves of its axis. For the first 20 miles the breadth varies 

 " between f and 1| mile, then tapering to the head. The total water area 

 "is 28| square miles ; the average depth is 22 \ fathoms, and the depth 

 " along the axis averages 40| fathoms at low tide. The outline of Loch 

 " Fyne suggests its division into two distinct parts, which are found to 

 " correspond with the conditions of depth also. From Otter Spit to 

 " Minard Narrows is a distance of 7| miles, and this section has been 

 " termed the Gortans Basin. The depth in the Narrows at Otter is only 

 "15 fathoms, at Minard 17 fathoms; but between them the Gortans 

 " Basin sinks to a maximum depth of 35 fathoms, with a depth exceeding 

 " 30 fathoms for 3 miles. Speaking generally, Gortans Basin is a shallow 

 " and relatively wide hollow shut off by bars from the deep Lower Loch 

 " Fyne on the seaward side, and from the upper basin on the landward 

 " side. The upper basin, though narrower, is much deeper. The depth 

 " increases gently from Minard for 3 miles, until off Furnace it begins to 

 "increase abruptly, reaching a maximum of 75 fathoms off Strachnr, and 

 " only beginning to shallow off Strone Point, Inveraray. The depth in 

 " the centre of the upper basin is over 60 fathoms for nearly 6 miles. 

 " The form of the land bordering Loch Fyne has greatly restricted its 

 " drainage area ; and the only streams of any importance enter near the 

 " head of the loch. The tidal current, according to the Admiralty 

 " publications, enters Loch Fyne at Otter at the rate of 3| knots, passes 

 "through the Gortans Basin at 2 knots increasing to 2| at Minard 

 "Narrows, but then slackening until, off Dunderawe, near the lead of 

 " the loch, it is reduced to 1 knot." 



Method of Research. 



In order to carry out the purpose of the research, it was decided to fix 

 upon certain stations where examinations of the water of the area might 

 be made once each month. Accordingly the stations (numbered I.-V. 

 respectively in Plate II.) were selected. 



Station I., situated in Lower Loch Fyne, and on the line from Battle 

 Island (at the mouth of West Loch Tarbert) to Buidhe Island on the 

 eastern shore, was taken as a suitable position for obtaining a sample of 

 the pelagic life of Lower Loch Fyne. The remaining four stations — viz., 



* Mill — "Clyde Sea Area," Trans. Roy. Soc, Edin. Vol. xxxvi. (1892). 

 f Mill— 1 Report on Physical Observations, bearing on Circulation of Water in Loch 

 Fyne" (April and September 1896), Ibth Report of the Fishery Board, Part III. p. 262. 



