Movement, dive behavior, and survival of California sea lions (Zalophus californianus) posttreatment for domoic acid toxicosis

Published source details Thomas K., Harvey J.T., Goldstein T., Barakos J. & Gulland F. (2010) Movement, dive behavior, and survival of California sea lions (Zalophus californianus) posttreatment for domoic acid toxicosis. Marine Mammal Science, 26, 36-52.
Share Tweet Email

Actions

This study is summarised as evidence for the following.

	Action	Category
	Rehabilitate and release injured, sick or weak marine and freshwater mammals Action Link

Rehabilitate and release injured, sick or weak marine and freshwater mammals

A controlled study in 2003–2006 of multiple coastal and pelagic sites in the North Pacific Ocean, California, USA (Thomas et al. 2010) found that at least a quarter of stranded California sea lions Zalophus californianus treated for toxic algae poisoning and released back into the wild died or had to be euthanized, and released sea lions travelled further from the shore, spent less time diving or hauled out and made shorter, shallower dives than wild sea lions without poisoning. Nine of 34 stranded sea lions treated for toxic algae poisoning died or were euthanized within 7–43 days of release. The fate of the other 25 sea lions was not known. Compared to wild sea lions without poisoning, treated sea lions on average travelled greater maximum distances from the shore (163–186 vs. 35 km), spent a lower percentage of time diving (20% vs. 22%) or hauled out (33% vs. 39%) and made shorter, shallower dives (9 vs. 15 minutes, maximum 203 vs 286 m). In 2003–2006, thirty-four stranded sea lions with toxic algae poisoning (domoic acid toxicosis; 12 acute, 22 chronic) were taken to a rehabilitation facility. Drugs were given to control seizures and reduce brain swelling (dexamethasone). All 34 sea lions were satellite-tagged and released. Nineteen sea lions with chronic poisoning were fitted with tags to record dive behaviour. Released sea lions were tracked for <1–129 days in 2003–2006. Sixty-seven wild sea lions without poisoning were captured, tagged and tracked in 2003–2006.

(Summarised by: Anna Berthinussen)