VICTORIA -- Canadian and U.S. whale researchers say they are closely monitoring the health of a grey whale off the coast of Vancouver Island after it developed signs of injury after researchers implanted it with a satellite tag last year.

The satellite tag was implanted in the whale in Washington state on Sept. 8 by researchers with the U.S. NOAA Fisheries and Pacific Coast Feeding Group.

Satellite tags allow researchers to examine the movement habits and other information about whales while the tags are active.

When the tag was first implanted, the whale was considered in good health, and in two subsequent follow ups on Oct. 4 and Dec. 9, the whale appeared healthy, according to researchers.

On March 16, however, NOAA received a report that the whale was displaying lesions where the tag was installed, and on the opposite side of the animal.

Staff with Fisheries and Oceans Canada and the Vancouver Aquarium's Ocean Wise program then observed the animal. On March 31 and April 1, Canadian teams administered antibiotics to the whale and collected breath samples from it to investigate for any type of infection.

Paul Cottrell, marine mammal coordinator for Fisheries and Oceans Canada, says that a CO2 rifle was used to shoot darts full of antibiotics into the whale, which is a technique that has been used on other marine mammals.

The breath samples are now being examined in Canadian labs to look for any viral, fungal or bacterial pathogens, according to Cottrell. The results of the tests are expected in two to three weeks.

Researchers from Canada and the U.S. have since created a panel to discuss what the next step for the whale and the satellite tag should be.

"This has been a huge collaboration with NOAA," Cottrell told reporters Tuesday.

After reviewing photos and a veterinarian's report on the whale's condition, the international panel has decided to leave the whale as it is and regularly monitor its condition moving forward.

Researchers say the whale is not acting unusually and is still travelling with its family along the coast of Vancouver Island.

"The panel agreed that the lesions did not pose an imminent danger to the animal’s health," said NOAA on an update on its website Tuesday.

"We are hopeful that once this satellite tag is extruded, the tissue around the tagging site will heal. But we will continue to monitor the whale’s condition closely," said the organization.

Researchers say the intent of this tagging study is to examine the movement of the Pacific Coast Feeding Group of gray whales. This feeding group includes about 250 grey whales who stay around the Pacific Northwest during the summer, near B.C. and Washington state, when most other grey whales migrate as far north as Alaska to breed.

Members of this feeding group are still considered a part of the general eastern Pacific grey whale population, which numbers about 20,000, according to NOAA.

Three of the roughly 250 grey whales in the Pacific Coast Feeding Group were implanted with satellite tags. The tag on this whale is the last remaining active one.