Thursday, January 4, 2024

Life & Death In Stanley Park


There have been a couple of sights in and around Stanley Park that have really caught the eye of the locals lately. One of them is the collection of sea lions, seals, and seagulls that have suddenly congregated around the end of Coal Harbour. They have all come for the herring which have mysteriously appeared and are providing a surprise Xmas feast. 

Herring used to be the most plentiful fish in B.C. until the commercial fishery nearly wiped them out in the 1960's. This had a profound impact on First Nations culture and the coastal ecosystem. Herring are one of the most important fish in B.C. as they are the principle diet of other fish, seabirds, and sea mammals and are critical to the diet of Chinook salmon which in turn are the primary food source of the Southern Resident Orcas. 

Herring spawn by the millions with each female laying 10,000 eggs or more, and when the males release their milt to fertilize the eggs they turn the ocean into a milky aquamarine colour that can stretch for miles along the coastline. Unlike salmon, herring are repeat spawners and once they have matured they can live for up to 10 years. However, just like salmon they have a homing instinct that allows them to return to where they were originally born.

A group called the Squamish Streamkeepers has been successful in re-introducing herring to False Creek using artificial spawning substrate panels for the eggs to lie on instead of eel grass, the native spawning substrate. In 2021 they expanded the program to Coal Harbour. But another key factor are dock pilings, which in the past used to be creosote which is basically toxic to herring. New docks, like the ones at the end of Coal Harbour, made out of concrete and steel provide a habitat that is more conducive to spawning herring. It takes 3 years for the eggs to hatch and mature at sea but it seems the program is a success as evidenced by the feeding frenzy going on. Hopefully they won't eat everything and the fish will have a chance to spawn.

Meanwhile over in the Park itself another type of harvest is underway, and one not nearly as positive, as workers try to cull all of the infected hemlock trees. Over the past 5 years an ongoing infestation of the Western hemlock looper moth has devastated the Stanley Park forest as well as many trees in North and West Vancouver. While it's a native insect that normally attacks trees in 20 year cycles, conditions have allowed the moths to persist way beyond their normal time frame and now a staggering 166,000 trees have to be cut down in order to prevent injuries from dead and dying trees.

According to the Forest Service the Western hemlock looper is one of the most destructive forest defoliators in B.C. They overwinter as eggs laid on the bark and then hatch in late spring. The larvae then feed heavily on the foliage of mature stands throughout the summer. The larvae are wasteful feeders gobbling up both new and old foliage and leaving behind partially consumed needles. In late summer the larvae pupate and are in flight until early fall.

Severe defoliation leads to top kill and tree mortality and if you walk through the Park you can see that almost every hemlock tree is nothing but black branches and the trees are all dying. It's a sad and depressing forest and a huge mess to clean up. Fortunately the Red Cedar and Douglas Fir trees seem to be spared. Most of the wood is being left behind as nursery logs but the branches and brush have to be cleared away in order to not become fuel for a forest fire which is increasingly becoming a real possibility.

So on one side of the Park we have what looks like a successful return of the herring while inside the Park the trees are dying at a furious rate. It's Life and Death in Stanley Park but it sure provides a lot of photo opportunities.