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Post by mwardncsu on Jun 7, 2013 10:19:22 GMT -5
My only question on that study was the fact that it was done on the flats - 2-3 ft water with "deep" water of 20-30 feet in the channel as I understand it. In those shallow depthts the water temp would be more consistent across the whole depth - not have a refuge of colder, oxygenated water deeper. I've not read the report in detail, but in a quick review of the presentation that they collected fish and put them in a water pen to hold and monitor - this pen in in the 1st few feet of the water surface and there is little room for the fish to swim, and we know stripers have to keep on the move. Just makes me wonder about the techniques.... again, I need to get some time to read the whole thing in more detail. Same questions arose from the satellite tagging studies where the fish were out of the water for a few minutes to insert the satellite tag (vs. maybe 30 seconds in a normal C&R).
Does not change the fact that the fish are more stressed as the temperature goes up and their mortality rate increases. Just makes me ask questions about the techniques and the different the variable environments play.....
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Post by striperseeker on Jun 7, 2013 10:37:39 GMT -5
I have read another study that Mike references. This was about striper mortality related to type of hook used to catch the fish. This study found that circle hooks had a mortality rate of only 5.4% while normal J hooks had a mortality rate of 16.3%. However, this was not a statically significant difference. This means this study found no difference in mortality rates based on the type of hook. However, there were problems in the random sample. They used volunteer anglers to do the fishing and most refused to use circle hooks. So the number of fish caught on circle hooks was too small to give statistically significant results. :>(
On the other hand there are several other studies about hook type. One set of studies find that mortality rate goes way up if gut hooked and goes way down if they are hooked in the mouth. Another set of studies shows that there is a much higher percentage of gut hooking if J hooks are used but circle hooks tend to hook in the mouth. So by using circle hooks you greatly increase the probably of striper survival.
So by switching to circle hooks we can greatly increase the survival rate of stripers we catch and release.
An interesting outcome from this study of Hudson River stripers, is that the amount of time the fish was played (how long it took to get the fish into the boat) did not affect mortality. I don't know what to make of this. The theory on our forum has been that the fish uses more oxygen the longer it played and they die from the lack of oxygen. But if the Hudson study is correct, that is not true. Interesting.
But I think we can conclude switching to circle hooks will really help with catch and release.
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Post by striperseeker on Jun 7, 2013 10:44:09 GMT -5
You are right Mike. The method (for all the studies I have seen so far) seems to be to hold them in tanks and count the fish that dies. I have not read the Wells article in full yet either. But while I am recovering from knee surgery, I have plenty of time to read the full articles and report what they said.
This sure does give us more to think about.
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Post by mytoyzfishing on Jun 7, 2013 13:08:20 GMT -5
I dont get into many of the more "controversial" discussions but I will give my .02 for what its worth. I'm no expert on fish mortality and havent seen any real hard study on the subject other than what we all experience and post up. Since I am still learning the whole striper thing, I cant tell you the last time I have caught more than 2 stripers in a day of fishing to begin with. But when striper fishing, during the cooler months I release all my fish. In the warmer months I will catch my limit and to the freezer they go. Once I've caught my limit I stop fishing for stripers and move on to fishing for something else such as catfish, bass, or bluegills. Just my opinion.
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Post by striperseeker on Jun 7, 2013 13:46:41 GMT -5
I do the same thing. I have switched over to circle hooks and have noticed that all the hooks have been set in the mouth.
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BentRod
Global Moderator
Posts: 2,252
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Post by BentRod on Jun 7, 2013 16:45:51 GMT -5
There's a lot of questionable studies out there. If they use release tanks, then I'd disregard it right off. It's a very difficult subject to study. The bottom line is that there is a 100% without a doubt increase in stress on stripers that are exposed to water temperatures over 70deg for extended periods of time. Nobody can argue that. Whether they all die or half or whatever, we'll never have an answer for definitively. There's too many variables at play in each different body of water they inhabit. Like I said, at the end of the day, educate yourself on the subject and then do what you can live with and that's all that matters. Case closed!
Bigun, look what you started again!!
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Post by striperseeker on Jun 15, 2013 6:04:37 GMT -5
I am still looking up articles on releasing stripers and their survival rate. I found this interesting article done here in Virginia invovling satellite taged stripers. The title of the article is "Use of pop-up satellite archival tag technology to post-release survival of and habitat use by estuatine and coastal fisheries." In this study they used satellite tagged fish. Ten stripers were caught using J and cirle hooks. Only eight of the fish kept their tags on for the thirty day study. All eight of the released fish lived regardless of which kind of hook was used. Several of the fish were gut hooked with J hooks and they survived as well. The study was done in winter.
Only eight fish. The rule of statistics is that you have to have at least 28 observations to have any statiscally significant meaning. This study does give us evidence that releasing fish in winter means that the striper will survive. Also note that J hooks had no effect on survival rates. But only eight fish!!!! Not sure that I would trust the results.
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