An underweight seal pup with parts of its umbilical cord still attached is the first to be treated by the Vancouver Aquarium this year.

The tiny male was found alone on Anvil Island in the Howe Sound by a member of the public, and brought to the facility's Marine Mammal Rescue Centre Wednesday.

Aquarium staff were cautious about the rescue, as lone pups are often seen resting as their mothers hunt for food this time of year.

"We ask those who find a seal pup not to touch it and to keep their pets away. Call us, we'll assess the animal, then decide if a rescue is needed," rescue centre manager Lindsaye Akhurst said in a statement.

Those who spot an animal in distress are asked to call 604-258-7325 (SEAL) for immediate assistance from the rescue centre.

In this case, the pup was transported to the Vancouver facility where it is now being fed formula five times a day and being closely monitored because of its size. Weighing just 6.8 kilograms, its condition is considered critical.

When separated from their mothers, premature pups always face a challenge when it comes to recovery.

"They miss important early nutrition and support from mom, so they're not off to a great start," Akhurst said.

It was given the name "Emerald" after the birthstone of the month he was found.

The aquarium's rescue centre rescues and rehabilitates about 150 animals a year, with the goal of releasing them back into the wild. Most of its patients are harbour seal pups, but it has provided care for otters, sea lions, whales, dolphins, porpoises and other animals in the past.

Those wishing to donate to the program can find more information online.