Abstract

Having survived stranding, starvation, and exhaustion in January 1997, the neonatal gray whale at Sea World of California began to thrive. During the following months the calf consumed thousands of liters of artificial formula, gained thousands of kilograms of weight, and grew hundreds of centimeters in length. By six months of age, weaning was becoming a priority. After a month with very little progress, a new strategy was developed to try to accelerate the weaning process. The formula was diluted 20% every other day for 10 days in an attempt to decrease caloric intake from formula while maintaining fluid intake. This strategy combined with positive reinforcement and emphasis on solid food resulted in the calf being fully weaned by eight months of age. Her solid food sources have consisted primarily of a mix of krill, herring, squid, and smelt.

Since being weaned in August 1997 through late March of 1998, the calf has continued to pile up impressive numbers. Weight has gone from 4400 kg to 8170 kg. Length increased from 735 cm (24 ft) to 915 cm (30 ft). Daily weight gains have averaged 16.6 kg/day (36.6 lb/day). The caloric intake required to maintain these gains has averaged 30 kcal/kg. Girth to length ratios have fluctuated between 0.48 to 0.56. These numbers currently stand alone as there is no similar gray whale data for comparison.

The final chapter of this story will take place during the annual northward gray whale migration at the end of March 1998. It will end like most beached animal stories with the return of the calf to the ocean which once cast it ashore. The reintroduction of an 8600 kg gray whale to the wild will be no small undertaking. The plans require a 10.5 m (34 ft) ballistic nylon whale stretcher. They also require a custom 12 m (40 ft) shipping container for the move from Sea World to the U.S. Navy pier where she will be loaded onto the release vessel. The 180 ft (55.4 m) U.S. Coast Guard buoy tender "Conifer" will carry the yearling calf to the release site approximately 4 nautical miles off the coast of San Diego. As the whale swims away from the Conifer her telemetry package will consist of four devices, three Argos satellite transmitters and one VHF transmitter. The data received should include the whale's location, duration of dives, and depth of dives.