Wednesday, October 30, 2013

July 2013

Stream keepers

Another month rolls by and the nice wet weather continues to re-charge the watersheds bringing all kinds of nutrients and bugs downstream to the waiting newly emerged Wild Coho fry and what smolts still remain in the streams. A question asked the other day was “ How do fry and smolts adapt to the salinity of the estuary and the Salish sea at high tide when the ocean flows upstream” well here we go, most research has concluded that size is one of the factors in salt water tolerance, having said that fry can if introduced slowly to increased salinity adapt to a certain extent but will die if placed directly into saltwater until they reach the 7 to 8 cm size and when reaching around 9cm their hypo-osmoregulatory mechanism is fully functional which means that up until they gain size they can only survive with low salinity as in estuaries when tide flows in and out giving the freshwater a slow influx of salinity allowing the smaller fry to adapt over time. Of course once the fry reach the 9cm range they are now considered smolts and the majority will migrate directly into the sea while some may stay up to another year and then leave as 3 year olds spending another year before returning to continue the cycle. Now having said all that we now have another class of fry aptly named nomads who will freely move from stream habitat to brackish estuary waters then come fall will move back upstream into the headwaters for the winter leaving the estuary ecotone which is the transition between ecotypes, fresh to brackish or the tidal influence when high tide pushes back upstream turning the fresh to brackish. As mentioned before this is the important rearing area for fry to make the osmotic transition to the sea and most importantly for the fry a abundant source of Isopods, amphipods and yes the more common word bugs. So yes the fry can survive if all is well with the habitat, then comes the question why are some larger than others well the short answer is that those fry that move downstream into the ecotone have a higher temperature than the upper stream habitat hence the more abundant food and the increase in size noticed as they move back upstream to more freshwater habitat mingling with those who were more territorial and stayed in their habitat which they are able to defend some times quite aggressively.
Now having said that, here we go again, some fry have in studies been shown to leave the stream habitat as fry and return as adults wait for it, in only 2 years from exiting the stream. Now we have these same called nomads that move back into the stream habitat when conditions are right and spend the winter either in their natal stream or some times in non natal habitat, possibly from moving along the foreshore in the brackish water then migrating into another nearby stream to complete the freshwater cycle. Now you are totally confused here comes the simple answer, fish do what fish do and have been for thousands of years and other than what occurs in nature the biggest threat is loss of all kinds of habitat mainly due to mans activities in the watersheds. Just the other day as I was walking along the road I observed a neighbour exiting the ditch/stream and scurrying off into his yard when we approached leaving a strong smell of gasoline and what looked like a empty yogurt container with a greasy looking slick being swept away by the current so here is another case of knowing better but a case of what the hell who cares. He is not alone as many times I see the small stream that flows across Ware rd down through the back of the lumber yard and between the Cabinet store and the Chiropractors office sprayed with herbicide directly into the stream. This may solve your perceived problem with vegetation but the knock on affect it has on the ecosystems is immeasurable. So please be aware of other life than your own both plant and animal if you want a liveable world for our kids and their kids down the road. In regard to that note I would ask all residents to lobby the council for an herbicide and pesticide ban in Lantzville and think before you pollute and remember no matter how safe the corporations who manufacture the poison say it is it is still poison to all life yours included it just may take a little longer to kill you than it does to kill bugs and plants. [Read Cancer, ask the tens of thousands in Southeast Asia who have been dying and living with all the birth defects and cancers from Agent Orange for the past 50 years.]
For those who like to fish for there dinner there are lots of opportunities to catch some nice big Spring salmon out front around the Winchelsea Islands these days, these fish are probably heading into the Nanaimo River system so do not feel bad about catching them as they are probably hatchery fish, but remember to release any that are wild so future generations can experience wild fish. If you are lucky you may catch a white-fleshed Spring, which is either from the Columbia River system or from our own Harrison River. In my opinion one of the best eating Spring salmon you will eat.  Down at the beach please pick up any garbage you find especially those who choose to just drop there doggy bag where ever they want expecting either the Salish Sea to take care of it or someone else.

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