Climate Change Effects on Salmon

This summer and early fall are the driest and warmest we have had, and recent summers have been much the same. Those of us who fish are justifiably concerned with wild salmon numbers, particularly in rivers where climate changes will make great difference to salmon.

Here is a summary document that, at four pages, is short and worthwhile reading for all anglers:  https://cmsdata.iucn.org/downloads/fact_sheet_red_list_salmon.pdf. 

And for ocean effects, and there are many, this 2009 review document by Dick Beamish, Brian Riddell (who we know as CEO of the PSF) and others, covers all the countries rimming the Pacific Ocean that have wild Pacific salmon, in 11 pages: http://www.npafc.org/new/publications/Special%20Publications/LRMP_Synthesis.pdf. 

Sockeye are the most heat sensitive of the five species, and over 20 Degrees C is lethal to them. If you follow DFO’s sockeye panel stats, you will know that Qualark Creek temps moved into the lethal range at times this summer. And note that coho, in saltwater are almost as temperature sensitive as sockeye.

But there is more to higher temperatures than simply death. Higher temperature, has been accompanied by lower precipitation in summer, monsoon rains in the fall, and lower snowpack in winter, setting up lower flow, of higher temperature, and lower oxygen all summer long.

Lower oxygen is the result of fewer riffles that mix air and water together. And as chinook are mainstem residers for more than a year, they suffer the oxygen effects the most. And lower clearer rivers make fry more visible to predators, thus reducing their numbers. 

Pink and chum hatch in March/April and migrate to sea almost immediately, a period of high flow. The down side for them is that greater precipitation in winter smothers or washes out egg bearing redds – of all species really. 

But low flow in late summer, can eliminate most water for pink spawning. They mate in very shallow water, particularly riffles hardly six inches deep. If those prime spots are only a couple of inches, in addition to low oxygen, they don’t give the pinks enough depth to spawn, and thus they move to other water with small pebbles.

Low, warm flow has effects on all species. Chum return in huge numbers on Van Isle and tend to spawn on greatest flow; this results, when the water recedes, in huge areas of dead redds. A gravel bar on one river I fish, is 400 yards wide, and 600 yards long. When the flood subsides, the entire area looks like it has been bombed with very small munitions. All chum, and all dead. Chum waste as high a percentage as 90% even in the best conditions. 

I started wading through a pool of dead chum, washed behind a new log – and log movement changes river bed, both scouring out bottoms and burying bottoms. I calculated 10,000 carcasses and began walking through. Soon I was up to my thighs, then waist, then chest and rather than go down with the chum, I slowly backed out of them, and smelled like death all day.

But there are other effects. If spawning channels have no water to enter, those fish may not be able to spawn or may move to areas of lower success, or higher use by other species. If river flow is very low, it affects chinook the greatest, as they need almost a foot for a 20- to 30-pounder to torpedo through.

I have watched chinook that can hardly move beyond the tidal reaches of rivers, reluctantly spawn in the highest water, with the largest gravel. One pair would spawn and go, and the next day, another pair would dig up the previous redd and also spawn and go. This went on for a full month, ie. 30 days of repeat spawning and waste of virtually all chinook eggs.

It may be that the sudden rise in merganser numbers about a decade ago represents another climate change effect. If prey is easier to see, water is shallower, and slower, fry are easier to catch and eat, so add predation to climate change effect.

While sockeye have temperature difficulties, and pre-spawn mortality rises, as shown in Dr. Miller’s work, on Fraser subcomponents to as high as 90% (also a disease effect, PRV for example), they get an easier pass by residing in lakes. The downside is that, like Lake Erie that has algal effects this year on news video, lakes can acidify and become more lethal, in some cases changing the plankton (a bigger problem in the open ocean) the base of the food chain.

One effect of lesser obviousness is that lower, smaller rivers have less spawning space than when at normal levels. That means there is less main-stem place to spawn, and thus, the respawning phenomenon I have mentioned, and by more than one species. And the last to spawn would be the fry of greater numbers, usually chum. However, as chinook are the largest, can move the largest gravel, chum effect would be greatest on pink salmon and secondarily chinook, and sockeye.

Coho are a special case. They tend to spawn in side channels, and seasonal streams. In my winter fishing, I check on several such creeks to monitor the spawn. As coho can spend an entire summer in seasonal streams, they are most susceptible to low precipitation – even though coho hold on in freshwater the longest, in some rivers into January, waiting for highest water. 

These days, several streams, don’t get filled up enough to offer a good spawning chance. Some don’t fill at all anymore and from being ones where I have watched coho spawn for a decade, have not had water for the last five, meaning none of those coho survived (unless they spawned in other water, crowding other coho, too).

And those seasonal creeks usually shrink in low water, so potholes around root balls, provide the only habitat for coho through one summer and back into the next high-water event – that means not being able to migrate out in the first summer.

But in the past few years, I have watched those small pans of water disappear completely. It is hard to watch water that will support coho disappear with fry in them. Just so that you know, coho fry have orange tails, so they are the easiest to identify. As pink and chum migrate out immediately, chinook are mainstem spawners, and sockeye are associated with lakes, chances are those fry cutoff from river flow are likely coho. 

And when river flow goes down in summer, those small pools cut off from flow, are likely to kill all fry when/if that happens, it is coho that are most affected.

There is much more to say, but I will cut to the chase and end. For several reasons it makes sense for anglers to get involved with chinook netpens – along with all the other restoration and recovery projects. 

Chinook are around 12 months of the year and are our species of interest. But chinook and coho numbers (particularly in the Salish Sea for coho since the mid-nineties) have fallen over the years, so that, in Victoria, we now catch more US chinook in winter, because there are not enough Canadian chinook.

When you add to this that our orcas are in deep trouble, and reputed to eat mostly chinook (I’d say this is more because chinook are around all year, rather than the two months of other species, and the largest, rather than a dietary preference), it makes great sense to do what the South Vancouver Island Anglers Coalition has done and put in a netpen in Sooke Basin to raise and release chinook – for orcas and us.

The argument that that changes things for wild fish because there is more competition for food resources, I think unlikely, because there are far fewer wild fish around these days. Other types of competition can be solved by using diploided chinook that are sterile and thus cannot breed. Netpen fish also return to the netpen site and can be recaptured by anglers.

When you consider that the CBC – a Toronto-centred network – has done the Right Whale deaths in the St. Lawrence almost weekly this past summer, and there are 500 of them, rather than talk loudly about the 78 orcas left, it means we on the BC coast need to be stepping up to fund, or operate netpens for chinook as much as we can.

I am in contact with a dozen environmental NGOs, and they repeatedly call for ending the sport fishery to save orcas. I point out politely that the issue isn’t sport fishing, it is lack of fish, and that the real key here is to quickly increase chinook numbers. That means a greater willingness by DFO to authorize netpens, and sport anglers to step up. The other thing I say is that the people who man such operations are sport fishermen, and thus that the ENGOs should look upon sporties as allies on behalf of orcas, rather than enemies. I’d say it will take several years of polite suggestion for this to sink in.

Sorry to go on so long. There is far more to say, (for example, there is great need for DFO stats on 50% of stocks), but do read the documents above, and if you want to read more, Google climate change effects on salmon: https://www.google.ca/search?q=climate+effect+changes+on+salmon&ie=utf-8&oe=utf-8&gws_rd=cr&dcr=0&ei=YRjZWdTiH4K6jwP8lq2ICQ.

Big Brute Time

It is time for those who do not have boats to get their big chinook. All they have to do is amble down to a river that has a good number of chinook and fish away. The downside this year, and a long-term climate change problem, is that we have had no appreciable rain and it is early October, which is very late.

Chinook need almost a foot of water to torpedo their way upstream. A river like the Stamp is big enough not to have impassable riffles. But others, like the Campbell, where the river is controlled flow, and thus enough, but the Quinsam, where most chinook are bound, is a soft, little stream, not passable. The Nitinat is another. Chinook cannot rise above the tidal end near the lake.

With the Hobitan Main severely decommissioned a few years ago, a several-mile walk from the Red Rock Pool/Campus Creek stretch is required to get to the fish, and no one wants to drag a 30-pounder, three miles back to the car. Alternatively, one can launch a boat near the hatchery operations on the lake and row across to the river. That means a return trip through the Nitinat wind later in the day, and it rips 30 mph on an average day.

Wherever you go, three methods take chinook in freshwater. First, spinners and spoons will take a few new fish, but unless there are lots of fish – because the percentage of biters is very low – better bring some back up gear. Chinook have the endearing trait that if your let you lure drop to the bottom a fish may go down and pick it off the bottom (a trait shared only with the occasional chum). 

On the other hand, if you are using spinners, sizes 4 and 5, any coho in the school of larger fish will typically beat chinook to the shiny surfaced lure. So, even if it looks like there are no coho around, you may just catch a few. Note that they are lighter than chinook, so dragging them back to your car is less effort.

The second method is the gear angler’s bread and butter technique: dink float fishing. The float is threaded onto the mainline, with the line circling the float once for friction, and then slid up the line. A three-way swivel is Palomared to the line end, and pencil weight added to the resultant tag end. To the swivel, a two- to three-foot leader is attached with wool or fabric ‘egg’ to a 2/0 to 5/0 hook.

The line is cast above the fish, and then, rod tip in the air and mending line, the float runs downstream. At the fish level, the egg is presented at nose level and passes through the school. Chinook behaviour includes their opening their mouths, mouthing something that comes at them, then releasing it after a few seconds. This is called a passive bite. The fish does not strike and run as a coho or trout would. It simply holds its station, holds the wool, then lets it go.

The angler sees the float stop, or pass under the water. That is the time to strike to drive the hook into the chinook’s bony mouth and the fight is on. Note that allowing the float to free spool down stream is the correct method of chinook fishing. Any other method that has a weighted hook and lure cast across the chinook school, and then reeled back, typically results in snagged fish. This is bad form and you should avoid it. The same can happen with a spoon or spinner, and if you snag more fish than biters, you should switch to the dink float setup that uses chinook behaviour to take them fairly. Snagged fish must be released.

The third method of chinook fishing, is fly fishing for them. You want a big school, slow water speed and shallower water that allows your fly to sink to mouth level and pass downstream just as one would do with a dink float setup. You need a sink tip line and a handful of detached tips in a pouch that can be added to the sink tip until you have achieved the right amount of sink. 

It is important to have short leaders of two- to four-feet so the fly is at the level of the tip and not floating above it. In a school of 1,500 or more chinook, there will always be some fish that don’t see the fly just in front of the tip, and so you will receive a bite, which again, is a stop, and then a let go.

You will feel your line rasp as it passes over backs, flanks and fins, but that is not a bite. A bite is when the fly stops, something that will only happen in moving water, when something stops it. Pinks, like chinook also just stop a fly, as in without moving up, down, forward or back, the fly just stops for a few seconds. If you don’t strike it, the fly is then let go, and it continues passing down with the current.

Note that with all methods of chinook angling, circle hooks will markedly reduce the snag potential. Circle hooks should be considered mandatory when chum fishing, as these fish school so closely and in such large numbers. A local spot for these is the Sooke River. Above the Basin is fly only.

Check Van Isle freshwater, salmon retention regulations here: http://www.pac.dfo-mpo.gc.ca/fm-gp/rec/fresh-douce/region1-eng.html.