Coho Fry of the YearFell ChannelThe colder than usual winter we experienced on the Lower Mainland meant that I would have to wait extra-long for the Coho fry to emerge from the gravel this year. After visiting MacKay Creek in late March and seeing dozens of tiny fry, I couldn't help myself but visit Mosquito Creek every 2nd or 3rd day until I was finally able to spot some fry. The fry were spotted in the Fell Channel a day or two before the juvenile trapping with Scott & Sandie on April 4th/5th. I was quick to point out the exact spot I had seen them with Scott & Sandie on the day of the trapping, April 4th. As a group we were lucky enough to see a couple in that very same pool, but nothing like the numbers I was seeing throughout MacKay Creek. I was surprised to see any year of the year in the Fell Channel, as I had not seen a spawning pair in there during the fall. I suppose it is quite possible they evaded my eyes, but another strong possibility is these fry had been swept into the intake of the fell channel. This would mean they were actually from the main stem of Mosquito, or had been pushed down all the way from Thain Creek. Either way it was a great find and they sure looked happy to be in the slower-moving channel environment. Thain Creek & Mosquito Main-StemThe channel where I had seen four adults was the Griffin Channel, and the possible redd (nest) Sandie had helped identify still showed no signs of successful yield all the way through to around April 14th. I decided to go to check out an area of Thain Creek where I had seen plenty of Coho spawning in the fall. First stop was the jimmy-rigged bridge over the creek that trail go-ers maintain. Sure enough in the back-eddys in the nearby area of the bridge I spotted some Coho fry of the year. This was a good sign, but I knew there would be plenty more where I was headed. Sure enough the holy grail of spawning pools had produced a great number of fry. In this particular area of creek I was able to see around 20 fry of the year, which was about the number I had expected to see. I am hopeful a large majority were able to avoid my eyes though. I had seen 6 spawners in this area, so only 20 fry would be a huge dissapointment if that was all that had survived. As I made my way down the trail, I decided to check out the West Alcove on Mosquito Creek, on my way to the alcove opening there was a large deep pool of slow moving water, protected by a large boulder. I didn't think I was going to be so lucky as to see any fry in the mainstem as the water was still fairly high, but protected from the torrent there were 3 fry of the year hanging out in plain sight! I continued down only a couple feet further to survey the alcove itself, but was unable to spot any fry in the alcove itself. Griffin ChannelOn the morning of Saturday April 15th I decided to check out the Griffin Channel. Sure enough, just above the top habitat pool I spotted my first pair of fry in the Griffin Channel. This was a hugely positive sign as that now meant I had seen Coho fry of the year in both channels, Thain Creek, & the main-stem of Mosquito Creek. I continued down the channel to see if there were more fry around the redd, but yet again not a fry in sight. I walked a bit further down the channel and was able to find two more areas with a few fry. This area of the channel is mostly fast flowing, but where the fry were spotted was in protected still water. The substrate was a dark muddy color and the fry blended in very well. By my estimate I had seen approximately 8 fry all together in the Griffin Channel. It was hugely positive to see fry in the Griffin Channel, but even in these wonderful channel habitats it seems the survival rates from egg to fry are extremely small. MacKay Creek ComparisonFirstly, I would like to thank everyone involved with the restoration and enhancement of MacKay Creek, including the recent estuary revamp. It is truely a gem in the urban world in which we live and all the hard work is definitely starting to show. After walking MacKay a couple times in April, I really wish we were so lucky as to have every creek in North Vancouver as healthy as MacKay... - Maybe one day. One of the first things you might notice when walking the trails of MacKay Creek, is the amount of woody debris in the creek itself. If you were to compare MacKay to pretty much any other creek on the North Shore, especially Mosquito, you will find there is really no comparison. Most creek beds now run debris-free, but MacKay Creek is an outlier. I am beginning to think this woody debris has a deeper impact on creeks than we currently understand. You can probably tell I am hinting at something, if so you are right. In just a few trips I was able to see, without a doubt, literally thousands of Coho fry on MacKay Creek. The results in 2017 have been phenomenal! I have been able to identify two particular areas of the creek where shoals, yes shoals, of fry hold up. The number of fry in these shoals come close to breaking the 50 mark. As one walks past one of these areas in particular, a 6-ft long section of streambed seems to move in synchronization! Fry of the year in these numbers are so rare, which leads to another comparison in which there really is no comparison. No other small creek on the North Shore has the number of fry as does MacKay. Don't get me wrong, I am extremely excited to see fry on Mosquito in the numbers I have seen. I do however think MacKay Creek should be used as a model, an example of sorts, which all the creeks on the North Shore should strive to become. I would recommend maximizing this video to full screen and keeping an eye on the bottom left area of the screen as that is where the most action happens.
I am definitely not doing Apple any favors by selling their iPhone 6 camera, but as I am sure you can understand these little guys are super camera shy. If you get too close they'll disapear. This was the best footage I was able to get.
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Juvenile Salmonid Trapping 2017***IMPORTANT*** Before reading this article it is important to know that any kind of fishing on Mosquito Creek is strictly prohibited. Additionally, juvenile trapping without DFO approval is considered a serious offense. This project was approved by DFO and conducted by two of it's members, I was there only for observation and support. *** Setting the Traps, April 4thOn the afternoon of April 4th, 2017, myself and two of our local DFO officers went to place traps in the Griffin & Fell Channels to observe numbers and size of fish species utilizing this habitat. Eight traps in total were set. Four traps in the Griffin Channel and four traps in the Fell Channel. During set up we observed a trio of Cutthroat Trout actively spawning in the Fell Channel, an activity never before observed by Scott, who has been working in the industry for over 20 years. As we continued down the channel habitat we also spotted Coho "fry-of-the-year," tiny fry which had just hatched this year. The fry were only spotted in one pool, and there were approximately 5 observed. We estimate that they had emerged from the gravel within the last week or two. The fish we expect to observe from the traps are Cutthroat Trout, Coho Salmon, & Steelhead (Rainbow Trout). Griffin Channel Results, April 5thOn the morning of April 5th we returned to the traps to see what, if anything, was inside. There was great anticipation and everyone had a good feeling about today, especially me. The first trapped was pulled from the Griffin Channel and it was alive with juveniles. I literally could not believe my eyes. As a volunteer on Mosquito Creek I frequent the creek and like to think I know the state of the sections of the creek and how much they are being utilized by fish. I had suspected there must be fish in this section, but I had no idea how many or how large the fish would be in this piece of channel habitat. For a normal passer by one might think this deep pool with slow moving water is a "water-tundra" of sorts, all but barren except for the pieces of woody debris and sandy bottom coated with decaying leave litter. Above you can see the photo of the fish pulled from the first trap . (We had transferred them into a pail at this point). I was hoping for about 5 fish, to me that would have been a successful trap. To my delight there were 21 fish in the first trap! The majority were Coho juveniles, 1-2 years old, with a mixture of juvenile & adult resident Cutthroat Trout. Sandie pulled the second trap, this trap was placed in the same pool as the first, and it too had fish in it, this time only 6, but a hugely positive result. As we continued down the Griffin Channel, more positive results, lots of healthy fish! ***All fish were measured, counted, and released unharmed - without the use of any sedatives.*** Fell Channel Results, April 5thThe Fell Channel runs more narrow, and does not have the same large slow moving deep pools with the gradient of the Griffin Channel. For this reason, three of the four traps in this section were placed in faster moving and shallower water. We expected fewer fish and this was indeed the case, the three traps averaged three fish per trap, also as expected the species observed were Cutthroat Trout by a large margin. There are really only two areas of deep slow moving water on this channel, one of which was the area where the fry of the year were observed, and so we did not set a trap in this area. The other deep slow moving pool proved to be utilized by Coho Juveniles as expected, 3 Coho and 3 Cutthroat were observed in this section. One of these Coho was the largest observed on this day, 111mm in length. We expect this is a smolt that will be heading out to brave the ocean waters very soon. Final Tally & ThoughtsAlthough no Steelhead (Rainbow Trout) were observed, the results were simply amazing, the final count was 59 Coho & 21 Cutthroat, an improvement from years past. Today I learnt how vital these man made channels are to the health of Mosquito Creek. I had always suspected that metre for metre these were much more valuable than the main stem, and today proved it.
With the help of community individuals, businesses, and other organizations I hope to further improve existing habitat and where possible add new beneficial features and channel habitat. |
AuthorKeegan Casidy Archives
January 2020
CategoriesMosquito Creek,
North Vancouver, British Columbia |