262
A. NELSON-SMITH
four years. Peculiarities developed in the zonation of Fucus species
and in the form of some plants of 3’. vesiculosus L. (Lodge, 1948 ; Southward, 1956). In Cornwall it was observed that on an exposed shore
where F . vesiculosus was previously represented only by its bladderless
form linearis Powell (evesiculosus Cotton), the increased weed cover
permitted the development of scattered plants of the more usual F .
vesiculosus vesiculosus. Such dense algal growth occupies space otherwise available for barnacle settlement, and moving fronds of the weed
brush away prospecting larvae. Settlement of Balanus balanoides, a
northern form already at a competitive disadvantzge with Chtham,alus
stellatus in south-west Britain, might well be discouraged by a pollution
incident occurring at the time its larvae would be seeking settlement
sites. Most available rock surfaces inspected after the wreck of the
“ Torrey Canyon ” were occupied only by spat of Chtham,alus, which
breeds later in the year. Similar zoogeographical differences affect the
survival of the topshell Monodonta lineata which is near its northern
limit in Milford Haven and was thus badly affected by the cold winter
of 1962-63 (Moyse and Nelson-Smith, 1964). Its recovery was checked
early in 1967 and again late in 1968 by serious pollution incidents (Fig.
18, p. 286), although farther south in Cornwall it appears to be more
resistant to oil and emulsifiers than the winkles (Spooner, 1967 ; Smith,
1968).
C. Carcinogenesis
Russian work quoted in the Batelle-Northwest report ( 1967)
associated papillomatous tumours in Baltic eels with deposits containing
fuel-oil, and Russell and Kotin (1956) reported carcinomas and papillomas on the lips of bottom-feeding fish caught near an oil refinery.
However, no direct evidence is to be found in the literature that spilt
oil can produce malignant growths either in marine animals or those
who feed on them, although Goldacre (1968) points out that changes
in the cell-membrane brought about by hydrocarbons could lead to a
breakdown in cell-to-cell communication and thus to cancer. Carcinogenesis associated with oily industrial effluents or motor exhausts is
usually due to benz(a)pyrene (3, 4-benzpyrene) and related polycyclic
hydrocarbons. These have been detected in marine sediments off the
coast of north-west France at concentrations up to 1.76 p.p.m. by
Perdriau (1964) and Mallet and Priou (1967), and in the Mediterranean
up to an exceptional value of over 3 p.p.m. (Bourcart and Mallet, 1965).
The maximum concentration found in edible molluscs by Mallet and
Priou was one hundred times less than this, although they found 0.16
p.p.m. in the viscera of a food-fish. Shimkin et al. (1951) detected 0.05-
A. NELSON-SMITH
four years. Peculiarities developed in the zonation of Fucus species
and in the form of some plants of 3’. vesiculosus L. (Lodge, 1948 ; Southward, 1956). In Cornwall it was observed that on an exposed shore
where F . vesiculosus was previously represented only by its bladderless
form linearis Powell (evesiculosus Cotton), the increased weed cover
permitted the development of scattered plants of the more usual F .
vesiculosus vesiculosus. Such dense algal growth occupies space otherwise available for barnacle settlement, and moving fronds of the weed
brush away prospecting larvae. Settlement of Balanus balanoides, a
northern form already at a competitive disadvantzge with Chtham,alus
stellatus in south-west Britain, might well be discouraged by a pollution
incident occurring at the time its larvae would be seeking settlement
sites. Most available rock surfaces inspected after the wreck of the
“ Torrey Canyon ” were occupied only by spat of Chtham,alus, which
breeds later in the year. Similar zoogeographical differences affect the
survival of the topshell Monodonta lineata which is near its northern
limit in Milford Haven and was thus badly affected by the cold winter
of 1962-63 (Moyse and Nelson-Smith, 1964). Its recovery was checked
early in 1967 and again late in 1968 by serious pollution incidents (Fig.
18, p. 286), although farther south in Cornwall it appears to be more
resistant to oil and emulsifiers than the winkles (Spooner, 1967 ; Smith,
1968).
C. Carcinogenesis
Russian work quoted in the Batelle-Northwest report ( 1967)
associated papillomatous tumours in Baltic eels with deposits containing
fuel-oil, and Russell and Kotin (1956) reported carcinomas and papillomas on the lips of bottom-feeding fish caught near an oil refinery.
However, no direct evidence is to be found in the literature that spilt
oil can produce malignant growths either in marine animals or those
who feed on them, although Goldacre (1968) points out that changes
in the cell-membrane brought about by hydrocarbons could lead to a
breakdown in cell-to-cell communication and thus to cancer. Carcinogenesis associated with oily industrial effluents or motor exhausts is
usually due to benz(a)pyrene (3, 4-benzpyrene) and related polycyclic
hydrocarbons. These have been detected in marine sediments off the
coast of north-west France at concentrations up to 1.76 p.p.m. by
Perdriau (1964) and Mallet and Priou (1967), and in the Mediterranean
up to an exceptional value of over 3 p.p.m. (Bourcart and Mallet, 1965).
The maximum concentration found in edible molluscs by Mallet and
Priou was one hundred times less than this, although they found 0.16
p.p.m. in the viscera of a food-fish. Shimkin et al. (1951) detected 0.05-