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108
Annual Report of the London County Council. 1910
First.—That the kind of fish implicated was plaice (including in this term flounders and dabs);
that small plaice were specially open to suspicion, and that there was a possibility that the question
of failure to remove the gut (i.e., imperfect cleansing of the fish) was an important one in connection
with communication of infection.
Second—That the fish were already infected before reaching the retail vendor. This fact was
already apparent in 1900, inasmuch as in that year at least three widely separated populations in
different parts of London, obtaining fish from retail vendors having no association one with the other
were involved in the typhoid prevalence.
The experience of the last 10 years goes to confirm these conclusions. It was not found possible
in 1900 or in 1903 to determine whether railway or steamer fish was in question. In the August and
September prevalences of 1910, however, all the retail vendors implicated had received steamer fish.
It does not, of course, follow that steamer fish is necessarily always at fault. It appears, indeed, that
railway and steamer fish are apt to be derived in some instances from identical sources in the North Sea.
It has been suggested to me that the possibility of contamination of small fish, in what are known
as the "nursery grounds" in the North Sea, is not so remote as might at first sight be supposed.
The publication of Reports on the Research Work of the Board of Agriculture and Fisheries has brought
to light facts of great interest with reference to the distribution of small fish. The first of these Reports
published in 1908, stated that large quantities of small immature plaice were being swept up by the
(North Sea) trawlers each year, especially in the summer months"; and that the species (plaice),
"was annually being caught in an immature state in vast numbers on certain grounds." The small
fish abound at some seasons in shallow waters, but a particular shallow water area, known as A3, which
with another area, B4, "formed the 'small plaice grounds' off the Danish Coast, is the only A area
(i.e., the only shallow water area) in which an appreciable quantity of plaice was caught." Again
in A., the Danish inshore waters, and the so-called "small plaice grounds," 83 per cent. were small,
while in B4, which is immediately outside this area, the percentage of small was 76.
Reference to the map, published with the Report just referred to, shows the position of the
area A , which comprises this offshore water, having a depth of 0-20 metres, bordering upon the German
and Danish coasts. The area is described (Annual Report of Proceedings under Acts relating to Sea
Fisheries, 1906) as being one in which "the 20 metre line extends to a much greater distance seawards
than on the English and Dutch shores. . . the ground shelves gently into the deeper water of the B4
area without any marked change in depth or bottom." The area is shaped somewhat like a reversed
letter L—thus H—the portion represented by the vertical stroke having its long axis north to south,
and extending in places as much as 20 miles and more from the Danish and German coast line. This
portion contains the important fishing grounds known as the Horn Reef, Sylt, etc. The horizontal
portion borders upon the German coast, and is narrower as a rule, than the vertical portion; at the
angle of the two portions is the mouth of the Elbe. The entire area comprises 4,750 square miles,
but the fish are apparently derived mainly from certain "grounds" within it. The division of the
North Sea into large areas, it is stated in Volume I. of the Plaice Fisheries Report, was one which was
necessarily adopted because of the impossibility of obtaining statistics as to particular fishing grounds;
for to disclose "the quantity actually caught on each particular ground would be regarded as a breach
of confidence by those who give the information. The 'areas' enclosing as they do a great number
of grounds, do not disclose information of this kind." The published reports, therefore, contain no
information as to the extent to which plaice are obtained from particular "nursery grounds" situated
close inshore or within the estuaries of the big rivers. The question of the three-mile limit must not
be overlooked; but there is always a possibility that fish caught by foreign boats may find its way to
the London market.
The subject seems deserving of further study, bearing in mind the known ability of some of
the small flatfish, e.g., the flounder (See Camb. Nat. Hist., Vol. V.) to ascend rivers; and the extent
to which special attention has even been devoted to catching such fish in tidal waters. Thus, half a century
or more ago, the Thames fishermen are stated by Professor H. G. Seeley to have used a "tuck
net" for the capture of flounders between Deptford and Richmond. The plaice, like the flounder,
is said to ascend slow rivers to some distance from the sea (Chambers' Encyclopaedia), and it has been
found to thrive well in fresh water ponds. In recent years the distribution of small plaice in some of
the Scotch estuaries has been precisely studied. (See British Marine Food Fishes. Mcintosh and
Masterman.) It is desirable, therefore, that more knowledge should be available as to all the "nursery
grounds" from which the smaller flatfish, particularly those of area A, are obtained.
The question of legislating, with a view to limiting the destruction of small plaice, has received
much attention during the last six or seven years; the fear being entertained that the North Sea would
be depleted of its fish. The admissibility of small flatfish to market may, however, prove to have
importance from an epidemiological point of view as well as from its industrial aspect. Many vendors
have assured me that the retail traders would welcome the imposition of a size limit. It is stated in
the Plaice Fisheries Report that at Billingsgate a 20 centimetre limit is imposed. This limit is not a high
one, but the rule at certain times of the year is clearly honoured in the breach as well as in the
observance.
It is worthy of note that during the period in which special attention has been directed to the
subject of depletion of the North Sea, the amount of small plaice brought to Billingsgate has notably
diminished. Typhoid fever in London has also shown a decline in this period.
The fact has been noted in earlier reports, and is amply confirmed by experience gained in 1910,
that some of the sufferers from typhoid fever have complained of a "gassy" and again of a "bitter"
taste in the fish, to consumption of which they have attributed their illness. In a Report presented