Wildlife Case Report: Sea Lion Pup

January 18, 2017

by Duane Tom, DVM; California Wildlife Center Malibu, CA USA



Sea lion by Dr. Duane Tom

California sea lions (Zalophus californianus) give birth to their pups around July. These pups usually nurse for the first 6 months but may stay with their mother about a year, before learning to catch fish on their own. For the past 3 years, however, California has been under an Unusual Mortality Event or UME for California sea lions. Thousands of pups have stranded with severe emaciation and other illnesses, possibly secondary to their poor body condition.

The patient

On March 18, 2015, a pup was rescued by California Wildlife Center’s Marine Mammal Rescue Team from a beach in Malibu, California. Although estimated to be approximately 8 months of age, she weighed only 8.1 kg, which is considered about what they should weigh at birth. A normal sea lion at this age should weigh over 25 kg. The pup was also shivering, presumably due to an absence of fat stores. Harsh lung sounds were ausculted.

Case management

Sea lion pup by Dr. Duane Tom

Upon presentation to our facility the pup began having grand mal seizures. We were unable to obtain an initial blood sample as is sometimes the case with these animals that present in such poor condition, likely due to a combination of hypothermia and hypovolemia. However, knowing that these young emaciated animals often present with varying levels of hypoglycemia we administered 16 ml of 25% dextrose solution intraperitoneally (IP) along with 200 ml of Plasmalyte-A with 2.5% dextrose administered subcutaneously. The pup was provided heat support and she was also started on injectable antibiotics for possible respiratory infection.

Normally, we hydrate all marine mammal patients on intake and gradually transition them from Emeraid Piscivore (Piscivore), to a fish gruel, and then onto fish; however, with severely hypoglycemic, seizuring animals we immediately provide them with nutrition using Piscivore as soon as they are responsive. We feel this helps to maintain a more steady glucose state, thereby decreasing pronounced hypoglycemic dips. We start their initial gavaging at 90 g Piscivore/400 mL water to help with hydration. Not knowing the animal’s stomach contents or capacity, we start with a gravity tubing. After the first 24 hours, we continued with Piscivore at a slightly more concentrated mixture of 90 g Piscivore/300 mL water, doing our best to even out her gavagings as much as possible throughout the day at 250 mL four times daily. The pup was also started on vitamins and other nutritional supplements. The pup continued to be very dull before having another seizure the afternoon of March 20. We repeated a dose of 16 mL Dextrose 25% IP, and then continued her Emeraid tubings once responsive.

Over the next few days the pup became more stable and active so we began a gradual switch to fish gruel. She continued to improve over the next 4 days and on March 25 we offered her a small fish, which she ate readily. It took several weeks, but the pup continued to become much more active, however she continued to shiver, particularly after meals, so we continued heat support until her weight exceeded 10 kg. Once completely on fish and housed with other sea lion patients, the pup continued to become more active and gain almost 2 kg body weight per week until her release on June 19 at Westward Beach in Malibu at a much more normal weight of 26.7 kg!

Sea lion by Dr Duane Tom

Emeraid Use at the California Wildlife Center

The California Wildlife Center receives numerous animals in poor nutritional states. At our wildlife rehabilitation facility we rely on the Emeraid product line as our initial nutritional formulas, whether it be Emeraid Piscivore, for our marine mammals or many species of sea birds, Emeraid Carnivore for raptors, or Emerald Omnivore for numerous other species. These Emeraid products often help our patients through their most critical period in rehabilitation.