188 
Part ill. — Ninth Annual Iteport 
Lochs Moidart and Aylort are two small lochs on the mainland to the 
north of Ardnamurchan Point, both opening towards the west. The 
depth of Loch Moidart is very irregular ; while the loch as a whole is 
comparatively shallow, at places even high up the loch there are deep 
clefts, e.g.^ above Eilean Riasga there is a sudden depth of 9 fathoms, 
while the bottom round about is only a few fathoms. In these deep 
depressions there is generally an accumulation of mud, but the bottom is 
chiefly of a sandy nature. The entrance is a very narrow and complicated 
one. Loch Aylort, on the other hand, is a loch which it is easy to enter. 
It is protected by Eilean Gobhar, and the average depth immediately 
inside the islaud is about 3 fathoms, but the upper part seems to be a deep 
ravine at one place, with a depth of 26 fathoms of water. The bottom of 
the lower part of the loch is comparatively clean, but that of the upper 
part is Hke Loch Moidart, clothed with a vigorous growth of sea-weed. 
Loch Harport, Skye, is the southern arm of Loch Bracadale, and is 
completely sheltered from the heavy seas which run in other parts of 
Loch Bracadale during south-west winds. Its average depth is above 10 
fathoms, but above Carbost the greatest depth is 7 fathoms, and at the 
head of the loch the shore dries for upwards of half a mile outwards. The 
loch is muddy throughout, and in places the mud is very soft. 
Loch Greshornish^ Skye, is an arm of Loch Snizort, running south-west 
and north-east, the opening being in the latter direction. Its average 
depth is about 7 fathoms, and its bottom is of peaty mud, the oysters 
obtained in it being stunted and poor. 
{h) Density and Temperature Observations. 
The observations on temperature and density which have hitherto been 
taken on the West Coast are few in number. Till some months ago, the 
oidy systematic observations taken in West Coast waters that I know of 
were those for an Irish Commission on Oyster Fisheries in 1869 at 
Ardrossan and Port Patrick, at neither of which places were there oyster- 
beds, nor are there ever likely to be. Now, however, daily temperatures are 
being taken at the two places in Scotland which yield the greatest number 
of oysters, viz., at West Loch Tarbert and at Loch Byan. A record of the 
sea temperatures at these places, extending over some years, and a com- 
parison of the temperatures of one year with those of others, and of the 
temperatures taken at different places, will be instructive, and will help 
us to arrive at something more than merely vague opinion as to whether 
oyster-spat can be obtained in abundance, so far as conditions of tempera- 
ture are concerned. Continental experiences postulates a temperature of 
65° to 72° Fahr. for the spatting and fixing of the brood of French and 
Dutch oysters. Whether the same high temperature is necessary in the 
case of the Scottish native oysters has not yet been decided. In any 
inquiry into this question of temperature, its relation to reproduction 
should be examined, and it should be further noted to what extent a high 
temperature shortens the pelagic existence of the oyster embryo, and what 
is the effect of temperature on the first embryonal and fixed forms. 
The observations on the ' Garland ' were taken last year between 5th 
June and 12th July, a period which was characterised by more than the 
usual amount of stormy weather. The density observations at selected 
places were : — 
