Sunday, May 16, 2010

Eastern Pacific Gray Whales

Out of death comes life, a concept as old as the first ruminations on life and death itself. This was graphically demonstrated in March when hundreds of people gathered daily to view a nine metre long dead male eastern Pacific gray whale that had washed ashore in an easily accessible area at East Sooke Park.

What a strange mixture of sadness over the death of this rarely seen creature and excitement in being able to view and examine it in such close proximity. Parents brought children to this once in a lifetime opportunity to inspect our marine dwelling relative, from the oldest grandparent to young toddlers, everyone was curious and fascinated by the whale’s appearance. Questions and rumours were flying as to the possible cause of death, kids were seeking answers, “why does….what is…..?”

Everyone wanted to touch it, to run their fingers over the fringed baleen, to wonder at the barnacles and sea lice that festooned it’s massive body, to examine and marvel at a lifeform so different from our own.

Gray whales are very occasional visitors to our local shores. From 15-20,000 pass by Vancouver Island twice a year on their 16,000 km (10,000 mile) annual migrations between their Baja, Mexico calving bays and their Alaskan feeding grounds but they rarely venture into the Straits and inlets (although one small population stays the summer just off the west coast of the island). They are known as baleen whales, as they filter their food through fringed structures on their enormous jaws. Baleen is formed from keratin, the same material that makes fingernails and hair. Grays are the only bottom feeding whale, they roll on their right side and suck in mud from the sea-bottom of the Pacific floor in areas which are rich in amphipods, isopods and tubeworms. The mud soup is filtered through the baleen, leaving small crustaceans, invertebrates and others as their meal. Although they are huge (to 45+ ft or 14m) and have large mouths, they have small throats and would choke on larger prey. Most of their feeding occurs while in the north. You can imagine the enormous amounts of food they need to sustain themselves during the migrations and the months they spend in the south, the females nursing their young, they are known to fast for 3 to 5 months.

East Pacific grays (our coast) were hunted almost to extinction in the 1890’s and again in 1920’s, perhaps only a few hundred remained, till finally in the 1940’s they were given international protection. The Atlantic grays unfortunately were not protected in time and lost their battle for survival and the west Pacific grays (Asian coast) have never really recovered and are still hovering on the verge of extinction. Grays were harvested to provide ingredients for margarine, cosmetics, gelatin, glue, paint, soap, lubricants and lighting oil among other products.

Whales are mammals, like us they breath air and birth live offspring which suckle milk from the mother (50 gal a day for a gray baby). The gestation period is approximately one year and the newborn calves can be 500-680 kg and 4.5 m in length. The mother’s milk has 53% fat content compared with 2% in humans, giving them the energy they need to grow and to prepare for their long journey north. Imagine the mother: spend the summer pregnant and feeding in Alaskan waters, stop feeding in any appreciable amount, then travel 8000 km (5,000 miles) to Baja, birth your calf, nurse it, swim another 8000 km while only having the occasional snack. The mothers have earned the name “devilfish” for their determined protection of their young but I think it is just as likely that they are cranky from hunger! Strange isn’t it, how a human mother is glorified for defending her children while a whale mother is viewed as a devil….

Outside of humans, the main predator of grey whales is the orca and many show signs of battle with teeth marks as lasting evidence of these encounters. Like a floating ecosystem, another embellishment of the gray whale skin are the many barnacles that festoon their massive girth. Colonies can weigh up to several hundred pounds as they hitchhike their way up and down the Pacific coast. They have evolved to time their spawning to the birthing cycles in the southern lagoons; the free swimming barnacle larvae then attach themselves to the whales, like lifelong tourists on an ocean liner. There is one specie of barnacle (Cryptolepas rhachianecti) which is only found on the grays. They do not feed on or harm the whales and scientists use the distinctive barnacle patches to identify individual whales. Another inhabitant of the whale body ecosystem are whale lice, parasites which feed on skin and damaged tissue. These in turn are preyed upon by small silvery fish known as topsmelt, living in symbiosis with the whales much as you’ve probably seen in photographs of small birds cleaning large mammals on the African plains.

Gray whales can live to seventy years and can ingest a massive amounts of polluted material in that time. Many contaminants can float to the ocean floor, where they can accumulate in the bottom dwelling species and are then eaten by the whales, which in turn feed their contaminated milk to their young.

No-one knows why that young male gray whale died, marine animals die all the time and only rarely do we see the evidence so close at hand. We can be grateful for the glimpse it provided into the foreign and fascinating world of marine creatures. Metchosin (Stinking Fish) was named for one such leviathan that washed onto our shores many years ago.