As winter turns to spring in April or so, land plants again produce leaves to capture the returning suns power and, with water, nutrients and minerals from the soil, restart their goal of growth and reproduction.
In the sea, diatom algae begin the same cycle in the spring except nutrients and minerals can be harder to find as the previous years growth would have used up the surface nutrients. This is why the Spring plankton bloom in Georgia Strait begins at the mouths of rivers such as the Squamish.
The water pushing out of the river valley into the ocean works much like a pump, drawing deeper, nutrient laden waters up from the depths to the surface where Spring sunlight and these precious nutrients allows hundreds of diatom algae species to sprout their green magic, often weeks ahead of the rest of Georgia Strait.
The lush green growth of spring algae bloom soon brings the grazers. Barnacles, mussels, clams, snails, crabs, starfish and hundreds of species of shrimp-like organisms release their eggs into the ocean to feast on this green bounty.
Of all these shrimp-like grazers, the most efficient is a copepod called Neocalanus plumchrus. You might say that plumchrus is Latin for "Fat Guy" as it is indeed fatter and therefore bigger than the other algae grazers and this makes it the perfect food for hungry young fish, especially herring.
Fisheries studies (Beamish in Nanaimo) have estimated that a square kilometre of Georgia Strait surface water can produce 36 to 72 tons of diatom algae per year, and that algae can in turn produce25 to 40 tons of Neocalanus plumchrus which in turn can produce 9 to 13 tons of herring and 1 ton each of Chinook and Coho salmon. These studies show that nearly all the diatom algae is utilized by grazers and Neocalanus plumchrus has found ways to get more than its share. Neocalanus plumchrus in turn is well utilized by herring. The reason that Neocalanus plumchrus must be so fat is that it only spends about 100 vulnerable days near the surface harvesting algae starting in earliest spring, and then it retreats 1,000 feet or more into the safe, dark depths of the inlet where it lives, mates and develops vast numbers of eggs.
As spring approaches, hundreds of tons of Neocalanus plumchrus, its eggs and its developing larvae rise out of the dark depths of Howe Sound, poised to win the race to devour the diatom algae bloom before the other grazers get started.
The eggs of a herring take about two weeks to hatch so the ideal time for herring to spawn would be about mid-March and, since the plankton bloom will begin at the mouth of a river, the ideal place would be near the mouth of a river such as the Squamish.Herring eggs need protection from waves and the herring sperm is activated best at a salinity of about 50/50 salt water and fresh water. These two requirements are met in the Mamquam Blind Channel just east of the 樱桃视频River as in the 1960s herring spawned there in the millions before industrial development brought their demise. From this handy spawning area they could lay their eggs so that the herring larvae would hatch out just in time to catch the earliest days of the Spring algae bloom and its most avid harvester, Neocalanus plumchrus.
The industrial development in the Mamquam Blind Channel is gone but a problem still remains from it. Unlike many of the oceans creatures that spawn their eggs directly into open water, herring attach their eggs onto kelp or eel grass which no longer exists in the Mamquam Blind Channel in any quantity. Edith Tobe is attempting to replant eelgrass but in the meantime the 樱桃视频Streamkeepers have put out hemlock trees as a substitute spawning material as natives have long used them to collect herring roe.
If herring spawn on the hemlocks in March, their eggs should hatch out in time for a 100-day feast on their favorite food, Neocalanus plumchrus. This would give them a big head start on returning to their massive numbers of not so long ago.
