Wednesday, April 23, 2014

Northern Elephant Seal

On Monday, the day after my brother died, Johnny and I loaded a canoe onto the top of the van and drove to Knight Park at the foot of Cascade Head to canoe across the Salmon River and do our monthly beached bird survey. And be soothed by the ocean's sound and smell.

It was a lovely day for canoeing the river and hiking the beach. The walk from the river to the south end of the beach, following wrack lines, was uneventful (i.e. we found no dead birds). But when we got close to the rocky cliffs blocking the south end of the beach, we saw a large gray lump that turned out to be a seal... or something. It did not appear alive at first but when we approached made a feeble attempt to wiggle forward. It had large red holes in its hide and we assumed it had been pecked.

Looking through my COASST protocol book that has all the information we need when doing a survey, I found a hotline number for stranded marine mammals and called it. She took the information and said a researcher would be calling me. Our protocol is to not interfere with nature unless the problem is man caused. So we retired to rocks at the end of the beach, a long way from the seal lump, ate our lunch and watched. 

The tide was coming in but still quite a distance from the beached beast. However, the closer the waves came, the more interest the seal displayed. We had seen its wake in the sand where it had pulled itself along from the base of the cliff to where we found it. Now, with the sound of waves growing closer, the seal wiggled forward more often. Eventually, after about 40 minutes (we took a long lunch), water and seal met and it was able to swim away. We thought that was a happy ending.

Well, maybe not.

The researcher did call while we were doing our return trip survey and after the seal was safely at sea. He asked if we had taken photos. Johnny had. Since we don't have one of those magic phones that can send photos immediately to a recipient, I offered to email them after we returned home later that day. He told me before seeing the photos that he suspected our seal was a juvenile Northern Elephant Seal and not stranded at all, but rather hauled out to shed its skin. I had never heard of such a thing. Thus began a steep learning curve about Pinnipeds (seals, sea lions and walruses) and Northern Elephant Seals in particular.

Here is what Jim Rice, Oregon Marine Mammal Stranding Coordinator, told us after he saw the photos:

This is a juvenile northern elephant seal going through what's termed a "catastrophic molt", which occurs annually April-August. Molting seals often appear sick, but this is a normal process in which they come ashore to shed their hair and skin. It takes several weeks to complete, and is often marked by irregular breathing, weepy eyes, runny noses, and damaged-looking skin. But as bad as molting animals may look, they are going through a normal and necessary process, and usually are not stranded.

Who knew?

I started reading up on elephant seals. The males get really huge, have ridiculous snouts that fall over their mouths and help them make incredibly loud roaring noises when they're fighting with other males. (Those vocalizations, I learned, so impressed the sound man for Peter Jackson's Lord of the Rings trilogy, that they were recorded and used as the main component for the sound of the Orcs.)

 A male elephant seal I would recognize, but how can you tell juveniles, like this one apparently was? Jim explained:

Elephant and harbor seals are part of a family group of pinnipeds called phocids or true seals. All members of their group lack a pelvic girdle and therefore cannot rotate their hind flippers under their bodies and walk the way the sea lion family group (otariids) can. True seals have short front flippers with claws on the ends and undulate on their bellies to move on ground. They also lack external ear flaps and use their hind flippers for locomotion in the water. Otariids (eared seals) have long paddle-shaped flippers that they use like wings to fly through the water and they are much more agile on land.

This seal was definitely not agile on land. It moved, when it moved at all, like some severely overweight inchworm. Indeed, these seals have massive amounts of blubber.

I found a site online that explained more about these strange pinnipeds:  "The Northern Elephant Seal, Mirounga angustirostris, is an extraordinary marine mammal. It spends eight to ten months a year in the open ocean, diving 1000 to 5800 feet deep for periods of fifteen minutes to two hours, and migrating thousands of miles, twice a year, to its land based rookery for birthing, breeding, molting and rest." Those rookeries are on beaches and islands off the shore of Baja California north to San Francisco.

More from that site about molting on the central California beaches where they also breed:

The Molting Period - April through September

"From mid-March to mid-September, elephant seals are present on the beaches to grow new skin and hair and shed the old – to molt.  Early in this period they share the beaches with the weaned pups which have not yet left for sea and the final weeks of the period they share with the juveniles who arrive for the fall haul-out.  The adult females and the juveniles are the first to appear with their number reaching a maximum near the first of May and all departing by the first of July.  The sub-adult and adult males begin to arrive in early May and are gone by early September.  Each molting seal stays in the rookery for approximately one month.

The seals come to the rookery to molt rather than grow new skin and hair continuously as we do because growing skin requires circulating blood just inside the skin – outside their insulating blubber.  With an internal body temperature near 100°F (38 C), and ocean water around 40°F (4 C), growing skin at sea would entail enormous energy loss.  A measure of how serious that would be is that the seals travel thousands of miles over several weeks and fast on the beach for a month to avoid paying that price."

So, I'm guessing that the juvenile seal we found on the beach was on a stopover on its way to its rookery, wherever that is, to finish molting. I hope it makes it.

On our return hike we surveyed more wrack lines and found one bird wing to id and tag. It was from a Western Gull.
It was nice to have a bird to practice our bird carcass id skills on, but not nearly so exciting as a beached and molting Northern Elephant Seal.

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