Hat tag on harbor seal pup. Photo by L. Zatorski Clarke
Each summer SeaDoc and The Whale Museum hire interns to help out with the San Juan County Marine Mammal Stranding Network. Part of their job is to check out abandoned harbor seal pups to see if they need to be taken into rehabilitation. We want to know if a particular pup has been seen before and if it has moved. Simple hat tags allow the seals to be identified from a distance. In the past, the San Juan County Marine Mammal Stranding Network has used standard plastic hat tags similar to those that are used on seals around the world. But what happens when these plastic tags fall off as the animal molts? Yes, that’s right: they become just one more piece of plastic marine debris.
This summer SeaDoc / Stranding Network intern Lauren Zatorski Clarke, an Oregon State University veterinary student, collaborated with the Marine Mammal Center in Sausalito, CA, to come up with a more environmentally-friendly way of tagging harbor seal pups.
Lauren engineered a replacement out of cedar. The blocks are cut, then sanded to remove sharp edges and the bottoms are scored to help them adhere to the pups’ fur when glued on.
Cedar hat tags showing inset lettering and scoring pattern on bottom
Preliminary field tests and tests on tagged animals in rehabilitation at Wolf Hollow showed that the tags stayed on the seal's heads and the lettering, done with a combination of engraving and a laundry marker, persisted and allowed identification at a distance.
When the pups molt next year, the tags will fall off. And because they are made from cedar, they will degrade naturally.
The information we get from re-sighting stranded and rehabilitated seals helps us understand harbor seal stranding patterns and rehabilitation success.
If you see a tagged seal in the water our on land, please report it to the San Juan County Marine Mammal Stranding Network (1-800-562-8832) and include the identifying letter and number in your message. Just remember to stay 100 yards away and use your binoculars. Thanks for your help!