Because they often ride the bow wave of a moving vessel, thereby making themselves accessible for tagging and capture, small porpoises and dolphins have been tagged with a greater variety of marks than large whales. In recent years, at least three kinds of static tags, including spaghetti streamers, have been placed on small and medium-sized cetaceans.
Spaghetti tags, placed in the animal's blubber near the base of the dorsal fin as it rides the bow wave, stream to conform to the contour of the animal's body as it swims ([App. Fig. A3]). It is not possible to identify the numbers on the spaghetti tag of a moving animal, although color codes may be used to indicate different species, populations, or tagging areas.
Button tags and freeze brands are placed on captured animals prior to their release. The button tags (App. Figs. [A4], [A5]) are placed in the dorsal fin and should be visible as the animal surfaces to breathe or as it rides the bow wave. At close range, the number, letter, or design may also be visible. Freeze brands ([App. Fig. A6]) are placed on the back or dorsal fin with a supercooled branding iron, apparently without pain or discomfort to the animal, and provide a permanent mark which leaves the tagged animal free of encumbrances. The use of freeze brands shows promise and should come into more extensive use.
Other static tagging techniques currently under investigation include the use of laser beams to apply small brands and the use of gas branding devices. Neither technique, however, has yet reached the field biologist.
The success of any tagging program using static tags depends on the resighting of tagged animals and the recovery of tags. For that reason, we appeal to readers to be on the lookout for tagged animals and to report sightings to one of the authors.
