. The Canadian field-naturalist. 1987 Gaskin: Updated Status of the Right Whale 301 the outer bay in 1983 than in 1980-82. Kraus and Prescott (1982: Figure 11) gave 1981 August and September surface temperatures for the region derived from bathythermograph readings, obtaining a range of °°C. Research vessels of the Department of Fisheries and Oceans, Canada, however, collected data in the same region in August and found a range of only °°C. While these data were admittedly taken only during the first half of the month, the difference is great enough to question the exact cali
. The Canadian field-naturalist. 1987 Gaskin: Updated Status of the Right Whale 301 the outer bay in 1983 than in 1980-82. Kraus and Prescott (1982: Figure 11) gave 1981 August and September surface temperatures for the region derived from bathythermograph readings, obtaining a range of °°C. Research vessels of the Department of Fisheries and Oceans, Canada, however, collected data in the same region in August and found a range of only °°C. While these data were admittedly taken only during the first half of the month, the difference is great enough to question the exact calibration of the equipment used by Kraus and Prescott. The peak distribution of Right Whales, and hence the apparent summer habitat range in the Bay of Fundy approaches, is shown for each year of the period 1980-83 in Figures 4 to 7. The total sightings are replotted with respect to bathymetry in Figure 8, and in Figure 9, with reference to the transition zone between thermally stratified and well-mixed waters, calculated from the Simpson/Hunter equation BH/ U^ (where B is the buoyancy flux due to solar warming, H is the mean water depth and U the amplitude of the tidal current) (see Garrett et al. 1978) and application of the average rate of tidal dissipation D (Greenberg 1978). The contours, which were plotted using log(H/D) = , correspond to a fairly abrupt transition from well-mixed to stratified. Smith et al. (1981) applied the same calculations to data obtained from the passages and channels between Deer Island and Campobello Islands, New Bruns- wick, and found close correlation of dense plankton with the transition zone, which would be marked by small-scale frontal discontinuities along which horizontal convergence effects trap and concentrate flotsam, zooplankton and small nektonic organisms. The biological importance of such anomalistic features was pointed out by Hamner and Hauri (1977), and it seems very likely that the Ot transition zone shown to the east of Gr
Size: 1942px × 1286px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorottawafieldnaturalistsclub, bookcentury1900, bookcolle
