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[Rodney]

Here is a video I just published on a two-year study on the latent/delayed mortality on chinook salmon released in marine sport fisheries.

https://www.youtube.com/watch?v=TRds3uMLAns

Previous studies have focused on either the first three days after the release, or tagging and tracking fish to wherever they go, but never looked at the first two weeks post-release. This video is just a generic overview of it, the results are quite detailed and surprising which will be shown in another video when ready.

[Rodney]

Several people reached out to me privately and suggested that we shouldn't be talking about these "problems", which would only be used by ENGO's as ammunition to shut down fisheries. That may be so, but I disagree because if it wasn't this than it'd be something else.

It is in every angler's best interest to find out exactly what our impacts are on fish. Rather than just saying "we have way less impacts than other groups", there are now solid data that can be brought into discussions. If there is a concern, then we can make adjustments to the way we fish to address it. If there isn't a problem, then we can actually make things even better.

This study is a great demonstration of what collaboration between the angling community and researchers can achieve. Data collection is hard work, and without the anglers' participation, we wouldn't have been able to capture a couple hundred chinook salmon in two days to sample. It is also great to have the team from Pacific Salmon Ecology and Conservation Lab at UBC so interested in sportfishing as well.

Hopefully results from the study can be used to handle some of the challenges we are facing right now. It would be fantastic to see more selective fisheries becoming available while protecting vulnerable chinook salmon stocks by lowering latent mortality of released fish.

[clarki]

Great post, Rod.

After I watched the video last night, I was left thinking ...Gee, it doesn't look good for catch and release. It was interesting to learn about the eye injuries that aren't noticed until after release and fin damage that doesn't heal. But to your point "it is in every angler's best interest to find out exactly what our impacts are on fish" , we need to know the good, bad and the ugly. It doesn't do the fish any good to bury or ignore data that doesn't support a given agenda.

I am curious, though, how the researchers control for the difference in post capture environments i.e. tank vs ocean. Certainly the swimming conditions in a land based tank that doesn't have prey or predators is a much different environment than the ocean. I'm curious how they control for those variables.

BTW, excellent video. Well shot and edited.

It will be interesting to see the results of the study.

Cheers. 

[RalphH]

Several people reached out to me privately and suggested that we shouldn't be talking about these "problems", which would only be used by ENGO's as ammunition to shut down fisheries. That may be so, but I disagree because if it wasn't this than it'd be something else.

How myopic some anglers are! Don't they realize the "ENGOs" likely know about this before you do or they do? Are they so naive to think the scientists running these studies aren't talking with  their counterparts at those organizations or with FN groups or that  information this information can be hidden? Also says much about their concern for the welfare of the fish.

[wildmanyeah]

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[clarki]

So, you’re saying that the results are a forgone conclusion and UBC and the Marine Sciences Centre are just wasting their time doing the research?

[wildmanyeah]

good point clarki your right i should be more open minded, thanks for correcting me

[RalphH]

There is no regulation I can find in BC non-tidal waters that require use of a special catch and release or not-less net either associated with FF only waters or catch and release requirements. It's suggested but it's not a requirement.

Most c& r studies have used a 24 hour holding period to determine mortality. In saltwater mortality is typically 10 to 15 %. Higher for chinook , a bit lower for coho. I have read the account of at least one guide who said it hasn't been unusual for his boat  to land 80 to 100 wild coho off the West Coast of the Island while searching for hatchery coho to retain. He wondered if a simple limit of something like 2 per person might be less harmful. Some other jurisdictions in North America have used limits on the number fish that can be caught and released per angler. I've long felt it's irresponsible to catch such large numbers of fish particularly when the estimated mortality ratio would produce more deaths in released fish that you can legally retain.

The information on non-lethal injuries, particularly the eye injuries should be useful to anglers. Perhaps anglers should be focusing on retaining fish that are less likely to survive than looking to retain a trophy etc where retention is allowed.  With this info we can get a chance to adopt more responsible practices regardless if it effects regulations or not. 

[clarki]

same as all the other studies

How embarrassing for Dr. Hinch,  Ms. Zinn and the other researchers to be conducting a redundant study! Isn’t a literature review to assess the current knowledge base, and identify gaps in knowledge, key to scientific rigour? A little bit silly of them, wouldn’t you say, to do a two year study when the results are already known.

Similarity, you’d have to question the Sport Fishing Institute too. Why would they dedicate resources over two years to a study when the results are already known?

[wildmanyeah]

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[wildmanyeah]

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[Rodney]

Great post, Rod.

After I watched the video last night, I was left thinking ...Gee, it doesn't look good for catch and release. It was interesting to learn about the eye injuries that aren't noticed until after release and fin damage that doesn't heal. But to your point "it is in every angler's best interest to find out exactly what our impacts are on fish" , we need to know the good, bad and the ugly. It doesn't do the fish any good to bury or ignore data that doesn't support a given agenda.

I am curious, though, how the researchers control for the difference in post capture environments i.e. tank vs ocean. Certainly the swimming conditions in a land based tank that doesn't have prey or predators is a much different environment than the ocean. I'm curious how they control for those variables.

BTW, excellent video. Well shot and edited.

It will be interesting to see the results of the study.

Cheers.

Thanks! This particular study mainly looks at how the injuries lead to mortality in the first two weeks which has never been looked at before. Previous studies had looked at the first three days. When I was at Katie's presentation last week, there were graphs of mortality % vs time for fin splits, scale loss, eye injuries, ec. Each injuries are rated so for example, there were comparisons between no eye inuries, mild eye injuries, severe eye injuries etc... There were also comparisons done with single vs treble hooks, flasher or no flasher, bait vs lures, net release vs gaff release. All very fascinating stuff. Comparison was also made for different age classes/fork lengths. Mortality did pick up after the first 3 days, some (I don't recall which ones, I think it was scale loss and fin splits) really picked up after 3 days. There were speculations that flashers would increase mortality, but so far that doesn't seem to be the case. Single hooks have done better than trebles overall as expected. Not a whole lot of difference between bait and lures as I recall. Net release is definitely much worse than gaff release. The amount of data coming out from this is quite impressive.

Katie and I plan to get together at some point in the next couple of months to do a follow up video so she can present the results I briefly summarized above. SFI is developing a set of recommended practices from these results which I will be presenting. One of the difficult question that has been discussed from this is does slot size limit really work. Would it be better to just catch and retain your limit instead of releasing 10 or 20 fish while retaining keepers? Mortality of some of the above mentioned treatment is much higher than I had thought, much higher than what Ralph suggested in the last post btw. Also, big adults survive way better than the subadults/juveniles.

[RalphH]

the rates I quoted were from the PSF website. They also noted these were well 12 to 15 years old. Back then and back until the first c&r studies a 24 hold period was used to assess mortality. I do know that radio tagging and other approaches have been used to extend the assessment time with not too much of  a change. Assessing by type of injury over a period of time is pretty unique afaik. I never would have guessed fin injury (splits) would be a significant factor or that they often don't heal.

[clarki]

good point clarki your right i should be more open minded, thanks for correcting me

Some days we all need a little dose of open mindedness…

[coastangler]

Great initiative, thanks Rod. Regarding the fin injuries, they definitely heal on rainbow trout. The Stocked trout that the FFSBC release on the LM lakes all come with their fins in a bad shape, I assume due to crowding when the fish are reared and you notice this on the fish you catch shortly after stocking. When you catch trout that was stocked a long time ago, their fins are back to normal and if you wait long enough the trout will have more redish and pink colors. I noticed this when fishing local lakes without wild trout that only get stocked during the spring, and caught trout in much better shape during the fall or early spring right before the next stocking.

So I wonder if fin injuries in the ocean just result in mortality due to predators or given enough time, they would actually heal.