An intense pycnocline at about 4 m. depth existed in Bute Inlet in August, 1967. This corresponded to the largest observed fresh water runoff into the head of the inlet. A major pycnocline above 10 m. depth was not observed in January, 1968, corresponding to small fresh water runoff. Correlating information derived from near-surface transverse and longitudinal sigma-t sections and drift pole plots with wind and tide data, the curvature of the inlet's lateral boundaries was found to influence the disposition of fresh water in any given transverse section. The direction of the surface layer flow was best related to the wind direction except in cases of high runoff when the wind only modulated the speed of outflow. The tide had remarkably little effect. Distinct changes in depth of the pycnocline along inlet were observed.Suggestions for future experiments are presented. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Distributions of salinity, temperature, and oxygen of Bute Inlet based on eleven oceanographic surveys between the period August 1950 to August 1952 have been examined. The shallow salinity structures of the various seasons can be classified under two main groups, those occurring at periods of small river runoff and the others occurring at periods of large river runoff. In general, the surface salinity increases to seaward and with depth during all seasons. The surface water along the western shore is almost always observed to be less saline than along the eastern shore. The salinity of the deep water is 30.6 % during both periods. The seasonal fluctuation of salinities at the surface is well-marked but below a depth of 60 feet no normal cycle exists. The temperature distributions of both seasons can also be grouped under two main seasons, namely, Winter and Summer. During both seasons the surface temperature generally increases to seaward. The temperature gradients in the upper layers during the Winter and Summer are positive (increasing vertically downward) and negative (decreasing vertically downward) respectively. From the Spring Transitional to the late Autumn, a well-defined temperature minimum, which becomes indistinguishable at the mouth, is evident in the intermediate depths. The water in the greater depths has a temperature of 8°C and remains almost unchanged throughout the seasons. The seasonal temperature variation of the surface and sub-surface water down to a depth of 150 feet is in phase with the air temperature cycle but below this it is less noticeable. Insolation and cold runoff water from the rivers are predominant factors in determining the fluctuation in the temperature. The concentration of dissolved oxygen is usually high in the surface layer. The water at the greater depth is not stagnant as evidenced by the oxygen concentration. The characteristic water types of this inlet are: the Deep Water, Runoff Water, Intermediate Water and Winter Surface Water. The three distinct layers in the oceanographic structures are: the upper brackish layer, mixed layer, and lower layer. The main circulation of this inlet is estuarine. Eddy coefficient of diffusivity of values 0.65 and 0.58 g./cm./ sec., have been determined for the water above and below the layer of minimum temperature respectively. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

A springtime mid-depth temperature minimum has often been observed in many B.C. inlets. The size and extent of the minimum varies markedly from year to year. This paper examines the temperature minimum more closely,in Bute, Knight and Jervis Inlets. Pickard (1961) suggested that a major factor affecting the size of the temperature minimum layer might be the outflow winds which blow down most B.C. mainland fjords during winter months when the Arctic air mass moves south to cover tne interior of the province. Using Abbotsford Airport as a station representative of outflow (no wind recording devices available in Bute, Knight or Jervis) for Bute, the size of the springtime temperature minimum was compared to the outflow of the previous winter for the period 1954-1973. There seems to be a rough linear relationship between the two. During 1972, 1973 and 1974 monthly cruises were made to Jervis, Bute and Knight - (making it possible to follow winter cooling on a month to month basis. This analysis seems to indicate that in Bute, at least, most of the cooling in the winter occurs during outflow situations. The actual formation of the temperature minimum layer (as shown in the cruises of February and March) appears to be partly caused by down-inlet advection of cold water from the head. It is possible that outflow winds may cause the disturbance which is the origin of the cold advection. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The bathypelagic copepods Spinocalanus brevicaudatus, Scaphocalanus brevicornis and Heterorhabdus tanneri have established relatively large, permanent breeding populations in Bute and Jervis Inlet, British Columbia. They are found only rarely in the shallower Strait of Georgia. The preference shown by Spinocalanus brevicaudatus and Scaphocalanus brevicornis was attributed to the deep living habits of breeding adults. The reason for H. tanneri's preference of deep water was not apparent from the distribution study. Two general patterns of vertical distribution were seen among the calanoid capepods in the inlets. The common interzonal species such as Calanus glacialis preferred a definite depth interval near mid-water. The deep-living species such as Spinocalanus brevicaudatus were found throughout the water column below the thermocline, in about equal numbers. Maximum numbers usually occurred in the depth interval immediately below the thermocline. Only females of Metridia pacifica showed a strong diurnal migration pattern in July. This migration became less intense near the head of Bute Inlet. The vertical distribution and migration patterns of Spinocalanus brevicaudatus, Scaphocalanus brevicornis and H. tanneri appeared to increase the chances of secual encounters in these relativelyt rare species. The interzonal and deep-living species showed contrasting life-histories. The interzonal species exhibited a well-defined breeding season, with adults maturing in the winter, and young appearing in the spring. The deep-living species did not show a yearly breeding cycle. Females dominated the population at all times of year, and a relatively small percentage of males and females were always present. A reduction in the male:female sex ratio occurred during or after the last moult in Spinocalanus brevicaudatus and Scaphocalanus brevicornis. In the animals the male has reduced mouth parts and probably dies soon after mating. H. tanneri males do not have reduced mouth parts. This species had a sex ratio close to unity at all times. An increase in total copepod numbers was observed with increasing distance from the head of Bute Inlet. An increase in the percentage of juveniles in the population of most species was also observed with increasing distance from the inlet head. Spinccalanus brevicaudctus, Scaphocalanus brevicornis and H. tanneri are redescribed. Comantenna columbiae is described for the first time. / Graduate