Biological Investigations at False River, Ungava Bay

Аннотация

During the months June to September 1958 the estuary of False River, Ungava Bay, was examined in the course of a study of the biology of the amphipods Gammarus oceanicus and G. setosus and the conditions of their shore environment. This work will be reported in detail when completed. The following is a general account of the area. The estuary itself can be divided into three components: the seaward arm is a wide shallow area running generally southward to a group of islands and the major tributary stream on the east bank; then follows a narrow deep arm running to the southwest and opening finally into the striking expanse of mud and boulders known as Kohlmeister Lake. ... Tidal currents were sufficiently strong to discourage more than one attempt at anchoring a canoe in mid-stream for measuring purposes. ... Sharp salinity and temperature fronts were observed moving up and down the estuary, and it seems that the central basin acts as a mixing reservoir receiving water from the north and south arms alternately. ... No evidence was found for deoxygenation in deeper waters; values obtained ranged from 7.1 to 8.1 ml. of oxygen per litre. ... Trees reach their definite limit along a line running northeast from the head of Kohlmeister Lake where there are some quite thick woods. Perhaps the most interesting aspect of the local flora is the extensive development of salt-marsh vegetation. ... During the summer only one lemming was seen, but evidence of much previous [mammal] activity was noticed. ... Seals were occasionally seen throughout the length of the estuary, but the greatest concentrations occur about the seaward parts of False River. Among the birds ptarmigan were particularly abundant in the vicinity of the base camp on the main eastern tributary of the estuary .... Of particular interest was the occurrence of frogs, tentatively identified as Rana sylvatica, in certain shallow pools at the extreme upper limit of spring tides on the salt flats of Kohlmeister Lake. ... Some two hundred fish were measured and examined in detail by my companion Mr. P. M. Gillespie who found them generally and heavily infested by gut and body parasites, and during a trip to George River copepod gill parasites were found in 70 per cent of the arctic char. In this connection it was interesting to observe that up to 40 per cent of the two Gammarus species on which this work centred were infected with the intermediate stages of as yet undetermined intestinal parasites of vertebrates. A few specimens of G. oceanicus were found to contain a single huge, apparently neotenous cestode, which virtually filled the body cavity. Gammarus will be worth examining in any investigation of parasite problems of the many fish, seals, and birds that feed on it. ...