Ministry of Agriculture and Fisheries

Abstract

IN September 1920 there was a scare about the heavy mortality amongst the oysters on the layings of the Thames Estuary. This scare passed to Colchester, and to every part of the East Coast, and similar death-rates were also mentioned from the south and west. The matter was investigated by the Development Commission's Advisory Committee on Fishery Research, but so far as we can see from the Report before us, no accurate estimations were made of the deaths, either beforehand, or afterwards when it certainly would not have been too late; the Table given shows that unusual mortality was reported in the summer of 1921 in the Thames Estuary, and the only possible excuses for the lack of accurate investigation then are either that reports were not sent in at the time, or that the Development Commission refused to provide the funds for such. Oyster planters estimated the deaths in 1920 at 10 to 60 per cent, against an average of 10 to 15 per cent., but there is no indication upon what these estimates were based. As Holt in Ireland records, losses from all causes of 39-6 and 54-6 per cent, on accurate figures, and Bulstrode showed that an English planter laid 241 millions in 13 years, and only picked up and sold 105 millions, we may be allowed to doubt the accuracy of the belief in this greatly increased and “abnormal “mortality, especially as no information is supplied as to deaths and the working of the layings in 1918 and 1919.

Ministry of Agriculture and Fisheries.

Fishery Investigations. Series 2, Vol. 6, No. 3, 1923. An Account of Investigations into the Cause or Causes of the unusual Mortality among Oysters in English Oyster Beds during 1920 and 1921. Part 1.: Report. By Dr. J. H. Orton. (assisted in Laboratory Work by Miss Edith Worsnop. Pp. 199 + 12 plates. (London: H.M. Stationery Office, 1924.) 15s. net.