Tuesday, April 1, 2014

Fun, Fun, Fun

Pacific White Sided Dolphin
I don't think there's anything more delightful than having a dolphin encounter.  The speed and grace of these fascinating and beautiful creatures is truly awe inspiring and, in combination with their friendly temperament, it's easy to see why they are many people's favourite wild animal. I've come across dolphins a few times on my ocean travels and every time it's been a magical experience but, when it happens on your own doorstep, like it did recently in English Bay when a pod of around 25 or so were just off the beach, then it's even more special.  I've never heard of dolphins coming into English Bay, and I've lived here my entire life.

Dophins in Georgia Strait
The Pacific white sided dolphins (easily recognized by their white undersides and curved dorsal fin) have been making something of a comeback in recent years in both Georgia Strait and Howe Sound and, while they are normally in smaller groups of under 100, there have also been many sightings of them in mega pods of a few hundred.  Given their estimated population is around 1 million and the fact they range all across the north Pacific, from the Mexican Baja to the Bering Sea and back down to the South China Sea, you would think we would see them more often but, because they tend to stay off shore rather than along the coastline, encounters with them are actually quite rare. What's changed recently, and brought them into contact with us, is the reappearance of the herring.

Pacific herring (Clupea pallasii)
As one of the most abundant fishes in our waters, Pacific herring (a species of the herring family) are the foundation of the marine food chain and one of the main sources of food for dolphins, not to mention seals, sea lions, humpback & grey whales, marine birds, and salmon. Sharing the identical distribution range of the dolphins they migrate in from offshore waters by the millions every year in late winter/early spring to spawn in sheltered bays and estuaries. Male herring release milt/sperm that colours miles of shoreline a chalky white and into this milky water the female herring release their eggs.  All those eggs and fish of course attract vast numbers of birds and animals, not to mention humans, to the feast.  Unlike salmon, however, herring don't die after they spawn and, those that escape, return to the deeper ocean where they repeat the cycle for another 5 - 8 years. 

Aerial view of herring spawn
Historically the herring fishery was many times larger than the salmon fishery, bringing in up to 250,000 tonnes annually in B.C. until it collapsed in the 1960's due to overfishing, and was closed. The same thing happened in the U.S. In those days herring were caught primarily for the "reduction fishery" an industry that reduces fish into fish meal and fish oil. Luckily the herring population was able to recover and, since then, under careful monitoring, the herring fishery has changed to the far more lucrative and less destructive herring roe fishery. Now only a fraction of the herring are being caught and they are being sold for a for much higher value. In 2012 for example only 13,200 tonnes of herring were harvested but generated a value of nearly $40 million dollars.

Herring roe, called kazunoko, is a traditional Japanese delicacy that sells for up to $150.00 per kilogram. However it must be harvested before the herring actually spawn so it means the herring have to be caught in large seine nets and then brought to processing plants where the female fish are stripped of their eggs. The remaining parts of the female fish, along with all the males, are reduced to fish meal and fish oil for use in fertilizers and fish food.  Any herring that aren't caught by these seiners will then spawn and try to return to the offshore waters.

Kazunoko sushi
Owing to weather, and other conditions, the fishery collapsed again in 1993 and since then 3 of the 5 major spawning areas for the Pacific herring in B.C. have for the most part remained closed to the commercial fishery. Only the Prince Rupert and Strait of Georgia areas have sufficient herring stocks to allow for a harvest and perhaps this explains why the dolphins are in the Vancouver area.  But an even more intriguing notion is that herring have returned to spawn in Howe Sound where, thanks to the efforts of a group called the "Squamish Streamkeepers" who discovered that by covering up creosote and concrete pilings with black landscaping fabric, the herring eggs can now survive and hatch.  Howe Sound now has a herring population of its own, and one that is increasing each year.

While the herring stocks may be making a comeback clearly something has happened to the sardines which saw a total collapse of the fishery this summer off the west coast of Vancouver Island, with not a single one being caught. This, in turn, forced the humpback whales far offshore to search for herring to eat instead and spoiled things for the west coast whale watching industry.  Between the humpbacks, dolphins, and the salmon, who depend on herring for up to 70% of their diet, perhaps that's another reason why herring stocks are down in some areas. There certainly are more questions than answers when it comes to understanding fish but clearly something has changed in this area and, with the arrival of dolphins, it can only be for the better. For now both us and the dolphins will have fun, fun, fun till someone takes the herring away.

School of Pacific herring