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Do you trust the sample and fly over method of estimating salmon catch rates?

  • I trust the current sampling method.

    Votes: 17 23.3%
  • I am skeptical and don't trust the count.

    Votes: 56 76.7%

DFW Salmon catch estimate method: Smoke and mirrors or pure science?

4K views 44 replies 19 participants last post by  chumkiller 
#1 ·
Simple poll, do you think the sample and fly over method of estimating sport catch is an accurate representation of the actual number of fish caught by sports fishermen?

There may not be a better way, but when reported catch rates for sports fishermen are announced, why do we see the only results of their calculations rather than the calculation itself with the sampling data and the resulting math?

Personally, I'd like to be able to see the actual calculations with current numbers that lead to their results published rather than the total posted and then re-hashing the statistical concept. Statistics can be skewed. They say they use a computer algorithm, but there is no explanation of the actual calculation. I think there are enough decent math minds out there that can properly vet the process if that calculation was exposed.

Given the low level of trust the current commercially biased DFW and their commission enjoys (and for good reason), I'd like to see this calculation (that shuts us down so often) brought out in the open with clear and concise numbers that lead to their decision.
 
#3 ·
I've been told(reliable source)that DFW counts the # of guide boats and assumes that the boat has a full charter and that the boat limited.
I have a boat that looks like a guide boat---I've always wondered how many limits I may have been responsible for:passout:
Terry
 
#5 · (Edited)
Keep in mind that their current method of estimating catch can both hurt or help sport fisherman depending on the day. They have technicians collecting catch information at random sites and then they expand this information based on boat counts taken from the air. On some days, the fish techs may collect data from a particularly successful boat launch or group of anglers and this might ultimately lead to an inflated total catch estimate. On other days, however, they may collect data at a particularly slow boat launch from a group of unsuccessful anglers and this would ultimately underestimate the actual harvest by sport fisherman.

If there is something the states could be doing better in my opinion it would be to collect more data. There really should be a fish tech at every single major boat launch instead of one here and there like we see now. Statistics are only as accurate as the data used to generate them and more data typically leads to more accurate estimations.

My guess is that commercial fisheries in the Columbia are even worse, maybe far worse, at accurately determining what is caught.

RM
 
#7 ·
Keep in mind that their current method of estimating catch can both hurt or help sport fisherman depending on the day. They have technicians collecting catch information at random site and then they expand this information based on boat counts. On some days, they fish techs may collect data from a particularly successful boat launch or group of anglers and this might ultimately lead to an inflated total catch estimate. On other days, however, they may collect data at a particularly slow boat launch and survey anglers that are less successful than what is actually occurring on average. In this case, the statistics would record a catch that is below what was actually harvested.

If there is something the states could be doing better in my opinion it would be to collect more data. There really should be a fish tech at every single major boat launch instead of one here and there like we see now. Statistics are only as accurate as the data used to generate them and more data means more accurate estimates.

RM

Your response is another "be careful what you wish for" argument. I'm not trying to hoodwink anyone for more time on the water. For me, I would appreciate the transparency and open data scenario whether it is good or bad for the sports fishermen.
 
#6 ·
I think the catch count methods are way off base. I know for a fact last year that some days were slower then others and they just took 4 fish for whatever boats they saw and that simply was not the case. I personally saw days where there was maybe 1 fish for 30 boats. Maybe the 205 to I-5 area was a little higher on down days but no way 3-4 fish a boat everyday. I know that it must be tough to count this number of anglers but it needs to be done on a day to day basis. This type of management leaves too much guess work and usually leaves the sport guy with the short end of the stick. My two cents says 20K springers were not caught last year below bonnieville!
 
#9 · (Edited)
My two cents says 20K springers were not caught last year below bonnieville!
Your :twocents: may be worth just that. There were many boats that got limits everyday from April 1st until the end. Do the math and 20,000 fish can get taken very quickly.

Lets ask some of the better guides out here what their boat caugth for the season? I'll bet they don't want to say, as it was very good and may result in more fish harvested than ODFW really thinks. My guess is the guides averaged about 100+ fish for each boat for the season. If the season was 20 days long in the prime times and 5 fish a day were taken by their boat. You have 100 fish. Are there 100 good guides out there? You bet. That may be 1/2 of the 20,000 fish there. How many other boats are out there besides the guides. At least twice as many do it for fun as for profit. If the other 300 boats a day got just 1.5 fish per boat per day. That would be another 9,000 fish.

Many people were off the river with limits before any plane had a chance to fly over, or any fish checker got out of bed. I talked with tons of people who were limited before 7am on many days. how many of those boats or fish were accounted for.

Don't get me wrong, i'm not saying I support the shorter seasons at all. We really need to look closely at the numbers and think how good we have gotten at catching these fish. It is pretty sick how many fish hit the bottom of boats last spring. If we truly believe that 20,000 fish didin't hit the bottom of boats last spring, then we are kidding ourselves. I'd bet the actuall number was 50% higher than that.




This is all hypothetical and only for a 20 day period From April 1st until April 20th. We all know that hundreds,maybe thousands of fish were caught well before April 1st.

If anything the numbers ODFW have put out there are underestimated.
 
#10 ·
Your :twocents: may be worth just that. There were many boats that got limits everyday from April 1st until the end. Do the math and 20,000 fish can get taken very quickly.

Lets ask some of the better guides out here what their boat caugth for the season? I'll bet they don't want to say, as it was very good and may result in more fish harvested than ODFW really thinks. My guess is the guides averaged about 100+ fish for each boat for the season. If the season was 20 days long in the prime times and 5 fish a day were taken by their boat. You have 100 fish. Are there 100 good guides out there? You bet. That may be 1/2 of the 20,000 fish there. How many other boats are out there besides the guides. At least twice as many do it for fun as for profit. If the other 300 boats a day got just 1.5 fish per boat per day. That would be another 9,000 fish.

This is all hypothetical and only for a 20 day period From April 1st until April 20th. We all know that hundreds,maybe thousands of fish were caught well before April 1st.

If anything the numbers ODFW have put out there are underestimated.
I think the catch rates can be closely estimated, however when fishing is so good, there are obvioulsy more fish around then forcast. This is the root of the real problem, not knowing how many fish are coming back so how long to keep the season open.
 
#11 ·
I believe in the statistical modeling and math used to make the estimates. However I do feel that they could greatly improve upon their data collection processes. Note that I said processes and not the checkers themselves.

Remember people, last year was an anomoly. Absolutely off the hook fishing so we can't really look at last years data and use it as any kind of a baseline or reference point.


Many people were off the river with limits before any plane had a chance to fly over, or any fish checker got out of bed. I talked with tons of people who were limited before 7am on many days. how many of those boats or fish were accounted for.
Absolutely true. The only 2 days I saw a fish checker were the only 2 days it took a little extra time to put that last fish in the box. A few of the lucky late-to-launchers really enjoyed getting a decent parking spot too. :)

It was a no brainer that we were chewing up impacts quickly and in danger of exceeding our allocation. I know that some people were begging the Compact to close it or further restrict the number of open days to keep from exceeding the impacts. Alas, they were ignored as usual because it is all about harvest harvest harvest. Sad. :(
 
#14 ·
Personally, I'd like to be able to see the actual calculations with current numbers that lead to their results published rather than the total posted and then re-hashing the statistical concept. Statistics can be skewed. They say they use a computer algorithm, but there is no explanation of the actual calculation. I think there are enough decent math minds out there that can properly vet the process if that calculation was exposed.
I agree, they could do a much better job of explaining how exactly they get their numbers. However, I don't think they are hiding anything on purpose. I think with any reasonable request they would be willing to share this information.
 
#17 ·
There's no conspiracy, there's no hiding numbers or coming up with false numbers just to give sportfishermen the shaft. They're estimates. Estimates are estimates, not actual numbers.

If you want to see how they calculate this, it's probably much more simple than you think. Contact the USFW, ODFW or WDFW and get ahold of a manager and ask him how they do it.
 
#23 ·
I'm afraid I would have to see some data supporting facts that 20,000 fish were caught below the dam. Or maybe I was fishing on the wrong river, even on a good day less than half the boats actually caught fish, and half of those were released. We will launch out of 4 different launches depending on where we choose to fish, but through it all I never saw one counter or game warden at any of the launches we frequent.
 
#24 · (Edited)
The whole point of a creel is not to sample everyone's catch everyday... The real nuts and bolts is the date and locations are randomly selected then the catch rates are expanded from the pressure count which of course does have to be very accurate (still only occuring on the day that sampling occurs).

The real art in determining an accurate creel estimate figuring out how many fish there are available to catch... Getting an accurate catch estimate is faily simple compared to estimating how many fish are availble to harvest.
 
#25 ·
The whole point of a creel is not to sample everyone's catch everyday... The real nuts and bolts is the date and locations are randomly selected then the catch rates are expanded from the pressure count which of course does have to be very accurate (still only occuring on the day that sampling occurs).WHAT? Random selections? expanded catch rates? pressure counts? I'm sorry, that sounds like political double talk to me. If you are going to extend or close the fishing season by the amount of fish caught, then you have to count those fish, not "expanded" catch rates, or "pressure counts" or "random selections". How can you say there were 20,000 fish caught without counting?

The real art in determining an accurate creel estimate figuring out how many fish there are available to catch... Getting an accurate catch estimate is faily simple compared to estimating how many fish are availble to harvest. And how can you figure out how many fish are caught, by how many fish are available to catch?
 
#26 ·
The whole point of a creel is not to sample everyone's catch everyday... The real nuts and bolts is the date and locations are randomly selected then the catch rates are expanded from the pressure count which of course does have to be very accurate (still only occuring on the day that sampling occurs).WHAT? Random selections? expanded catch rates? pressure counts? I'm sorry, that sounds like political double talk to me. If you are going to extend or close the fishing season by the amount of fish caught, then you have to count those fish, not "expanded" catch rates, or "pressure counts" or "random selections". How can you say there were 20,000 fish caught without counting?

The real art in determining an accurate creel estimate figuring out how many fish there are available to catch... Getting an accurate catch estimate is faily simple compared to estimating how many fish are availble to harvest. And how can you figure out how many fish are caught, by how many fish are available to catch?
No need to flame on my explaination of your a creel survey works. I suggest before you can ask any educated questions you google creel survey and see some of the scientific paper writen on creel surveys(not political).

The politics come in to play in interpreting the creel data and making management decision based upon the creel survey results. The creel survey simply estimate the rate of catch for angler and the nets... The real quess work begins when trying to estimate the actual runs as the fisherman start to catch them.
 
#27 ·
No need to flame on my explaination of your a creel survey works. I suggest before you can ask any educated questions you google creel survey and see some of the scientific paper writen on creel surveys(not political). I questioned your explaination because there were points that made no sense. Your suggestion that I should learn something about creel surveys before I was capable of asking an educated question however, was inflamatory. Your presumption that I knew nothing about creel surveys suggest that you have no thought of hearing other points of view, or explaining your comments.
As for creel surveys, or angler surveys, they are used all across this country for many species of fish, but the one thing they have in common is the simple fact that they actually speak to fisherman and ask them very specific questions about targeted species, time spent fishing, and harvest records. There are no observations on expanded catch rates or pressure counts, and the only mention of random selections were about random selections of different surveys conducted for the purpose of reports. Any estimations are from those actual counts, as an example: "of two hundred anglers surveyed 39% targeted salmon and 14% targeted sturgeon, etc.... Even this can be tainted, because without actually interviewing every angler, you could never really get an accurate count.
So, I will ask the questions again, "how can you state that there are a specific amount of fish harvested without actually interviewing anglers?
And, how can you estimate how many fish are harvested, by how many fish are available? And for those that have not heard of or know what they are, please explain what "pressure counts" and expanded catch rates are?
These are not uneducated questions, your statements were very specific and I quote; "The real art in determining an accurate creel estimate is figuring out how many fish there are available to catch..."
"The real nuts and bolts is the date and locations are randomly selected then the catch rates are expanded from the pressure count which of course does have to be very accurate".

 
#28 ·
If you guys want 100% accountability and accuracy in the sport harvest some changes must be made. How about calling in every fish harvested and released immediately after harvest or release. And then making it mandatory that all harvested fish be checked and tagged at checking stations. Couple these changes with the methods already used and there would be layers of checks to make sure all sport caught fish are accounted for and the counts are accurate.

betty
 
#29 ·
Average three or four, ramp survey numbers - get the fish to boat ratio - do a fly over and count the number of boats (called effort counts)- subtract a number (?) of sturgeon fishers- multiply to find an estimate of how many fish were caught -publish as fact.

Until they get the funds to man every ramp, every day this is the best they will do.

Also, from the final number, they also determine how many ESA listed salmonids were KILLED to determine allocation impact.

We need an small army of dedicated volunteers to work the ramps (officially, with the States) to bring the most acutate numbers for the compact to work with.

We also need to revisit (study) ESA mortality rates for the recreational fishery to determine if current ratios are correct.
 
#30 ·
Fast Water, I don't believe we need a small army, but I do think we have access to a perfect group of volunteers. "Wildlife biology students", They are the ones that will eventually take over control of this issue, why not utilze them for some of these surveys? That way they can see first hand just what is happening.

"Average three or four, ramp survey numbers - get the fish to boat ratio - do a fly over and count the number of boats (called effort counts)- subtract a number (?) of sturgeon fishers- multiply to find an estimate of how many fish were caught -publish as fact". This is exactly the kind of thinking we need to do away with(not you fast water the politicians). This kind of "survey" will always be used to skew the results. This is just an attempt to apease everyone by saying, "see we did a survey and these are the results". Doesn't solve anything, just adds to the conflicts.
 
#32 ·
I think the lower river mainstem fisheries that have big creel programs probably get pretty accurate catch estimates. Where the smoke and mirrors comes in is in the upstream and tributary fisheries where they do very few or sometimes no creel surveys at all. For these fisheries they just guess at catch numbers based on people who voluntarily turn in their catch record cards at the end of the year.
 
#33 ·
Criticizing a system that you know little or nothing about, and then calling it broken seems silly.
Saying the formula for the modeling estimates are skewed, but at the same time not knowing how it even works, seems ignorant.
Not saying it is or isn't, just saying just because you don't understand it's, doesn't necessarily mean it broken.
 
#34 ·
I think most people here understand the formula and the system, but believe it doesn't work. Those that may not understand it are not ignorant, they don't understand it because it doesn't make sense. And then there are those that think they understand, but can't see the flaws. Doesn't mean they are ignorant either, just means they see it from a different point of view.
 
#38 · (Edited)
First, if you have a problem with me, take it up with me, but not here. Second, I did read that report and it says exactly what I've been saying. Actual samples show less than 5000 fish caught and yet, they show estimates over 10,000. So, I will ask you again, How can you show an accurate harvest count without actual counts?
20% sample of caught fish does not show a valid count when it comes from a limited area.


"Complicated management requires real
time data to maximize recreational opportunities


Harvest estimates based on punch cards tend to be biased high
Data not area-specific
•No release information


"Estimated Oregon LCR sport sturgeon harvest based on punch card and creel data, 1997-2001"
Computer model generates weekly or monthly harvest estimates ?

This is all information form this report you listed, maybe you shouldn't assume others are not able to carry on an educated conversation without the facts. And if you want to carry on an educated conversation with me learn to spell so you don't embarrass yourself further.
 
#42 ·
The bottom line is, you can't get exact counts, but you can get close with statistics. Bear in mind one of the points to having an estimate is to minimize cost. People already gripe about how much money ODFW/WDFW spends, but imagine how much they would spend you increase the number of employees to get a near-exact count. I did say near, because you could never get an exact count, even with thousands of employees.

As far as your "wildlife biology students" post, you may have meant to say fishery biology students. Fishery students are the ones who will be assuming responsibility of fishery issues, not wildlife people. My point is, many fishery students work creel surveys during the summer. In fact, most schools in the PNW require their fishery students to be working for a department for at least 2 out of their 3 summers in school in order to graduate, and many take jobs that have a partial resonsibility of surveying anglers.
 
#41 ·
Calling anyone's response silly and ignorant does nothing but demean and ridicule someone who's knowledge and understanding is less than yours. To pile on and applaud such rude and boorish behavior is almost as bad. (See how I did that?)

Nice way to promote a meaningful discussion. Well done. :applause:
 
#44 ·
dartonvpr,

I suggest you travel to the Clackamas Regional Office and track down the Columbia R ppl and get them to answer the questions you seek. I am sure there are more than one induvidual that would be happy to explain their management plan and they will listen to your suggestions.
 
#45 ·
When you kill a bear or cougar in Oregon you must report it to a check station, same goes for Geese. If you are caught with Geese that are not checked in it's big trouble.

Why is it done for Geese and other animals and not for salmon?

I suggested a simple plan to check in at the end of everyday. You call in and report the number of fish you marked on your tag. If you fail to do this and you get caught on the water with fish on your tag that are not recorded, you lose your license. Very simple and very accurate. We are so advanced in computer technology that this system should work good.

It has to be cheaper than flying the river and having multiple ODFW creel checkers every day.
 
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