286
.
-
A. NELSON-SMITH
-MHWN
M T L
MLWN
.MLWS
,
I
1
27r
l J a n 67
25 -
23 -
21
19 -
17 -
15
13
I1
-
-
-
-
Littorina neritoides
feet
occasional
above
chart datum
Littarina saxatills
Littorina
littorpo
Jan679 -
7 -
5 -
3 -
FIG. 18. The distribution and abundance of some common winkles and topshells on
a shore at Hazelbeach. Milford Haven. Repeated surveys by Nelson-Smith (1967b,
1968a, 1968b) and Crapp (1969a) show the effects of oil-spills from the " Chryssi P.
Goulandris '' (Jan. 67) and the Gulf refinery (Nov. 68). Redrawn from Crapp.
Spaytinu townsendii was killed by a spill of fresh crude oil, but the
mortality rose to 55% where emulsifiers were also applied. Many
reports based on " Torrey Canyon " experience make the same point
-for example, O'Sullivan and Richardson (1967a, b), Nelson-Smith
(1968a, b), Ranwell (1968a), Smith (1968) and Wardley Smith (1968ac). Apart from their immediate toxic effects, emulsifiers spread the
pollution to the crevices and landward or leeward surfaces which all
but the heaviest oil pollution fails to reach. They also distribute the
oil in fine droplets throughout the depth of rock pools and coastal