. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. PORPOISE GROUP ORGANIZATION is part of a larger population of unknown size. Subgroup refers to those animals of the group which passed by shore at any one time. To assess surfacing associations of animals, a motordrive Nikon camera was used. This provided data not only on which individuals were present, but also on their dive times and on which individuals surfaced together. To collect this informa- tion, a photograph was taken each time one or more animals surfaced (up to frames/sec could be taken). The camera clicks we
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. PORPOISE GROUP ORGANIZATION is part of a larger population of unknown size. Subgroup refers to those animals of the group which passed by shore at any one time. To assess surfacing associations of animals, a motordrive Nikon camera was used. This provided data not only on which individuals were present, but also on their dive times and on which individuals surfaced together. To collect this informa- tion, a photograph was taken each time one or more animals surfaced (up to frames/sec could be taken). The camera clicks were recorded on magnetic tape, and comparison of times between photographs and the individuals recognized in those photographs provided individual dive times and a measure of whether any animals tended to surface at nearly the same time. The technique can be profitably used when the animals are close enough to the camera to allow for recognition of all individuals as they surface. The use of a 35 mm motordrive camera provided large negatives with the detail necessary for recognizing individual animals; yet the rate of picture taking was sufficient to photograph all animals as they surfaced. A cine-camera technique for determining group size, deployment, and speed (but not recognition of individuals) was described by Tayler and Saayman (1972a). Seasonal occurrence patterns were analyzed using analysis of variance (Sokal. JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN MONTHS FIGURE 1. The fraction of the possible days each month on which hottlenose porpoises were sighted. The Y-axis represents the ratio of the number of days on which porpoises were sighted divided by the number of days each month with winds less than 20 km/hr. July, November, and March were months of maximum porpoise sightings; in September, February, and May they were sighted significantly less (P < , analysis of variance, Sokal and Rohlf, 1969, pages 204-249, and Rohlf and Sokal, 1969, pages 168-197)..
Size: 1898px × 1316px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
