Isoflurane anesthesia in free ranging sea lion pups

California sea lion pups, Zalophus californianus, (n = 115), were captured and anesthetized for (mean +/- SD) 17.6 +/- 7.8 min on San Miguel Island, California (USA) in November of 1992. Mask isoflurane anesthesia allowed intubation in 7.1 +/- 2.74 min. Pups recovered and walked in 7.32 +/- 4.8 min. Mask anesthesia in pups resulted in relaxation in 45 +/- 14 sec. Safe, brief anesthesia was delivered in support of weighing, medical evaluation, and short surgical procedures. Recovery character of all pups was sufficient to permit release to the free ranging state immediately after surgery, saving labor, supervision personnel, and postoperative time.