Death of the orca killer whale L95 in Southern Residents is believed to have been caused by a fungal infection from tagging by the National Marine Fisheries Service, it has been revealed.
In a report the National Oceanic and Atmospheric Administration (NOAA) said that experts who conducted necropsy of the dead whale and carried out an investigation into the death have agreed that there was a fungal infection at the tag site that contributed to the illness, subsequent stranding and eventual death of the whale. A satellite-linked limpet-style tag was deployed on the 20-year-old adult whale in February.
The experts also noted that when the scientists were tagging the whale, the first attempt was unsuccessful because of which the tag had been in water during which it may have come in contact with the fungi and after the tag was deployed, the fungi may have infected the site.
“Additionally, the tag location, which was lower on the dorsal fin and at the caudal edge of the fin, placed the tag in close proximity to large bore vessels which could have facilitated the spread of the fungal infection throughout the vascular system as compared to a placement near more superficial smaller vessels,” it the report noted. Other factors that may have caused the death of the whale could have been “fungal bronchopneumonia, poor body condition and possible immunosuppression.”
While tagging has been pegged as one of the factors, NOAA is quick to point out that other whales have been tagged and none of them have resulted into death.
The causes of the death are still being reviewed and based on the findings, mitigation factors will be developed to limit impacts of future tagging on southern resident killer whales, the report noted. For now experts have suggested that tags exposed to sea water shouldn’t be used and before tagging a whale, cetacean anatomists should be consulted to determine the best location for tag placement.
The whale carcass was recovered by the Department of Fisheries and Oceans of Canada off Nootka Island, British Columbia, on March 30.