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Moon Myths?

Blog by: Scott Brands 1/14/2020
This winter I’ve been reading many books related to fishing. I recently came across a book entitled “High Percentage Fishing: A Statistical Approach to Improving Catch Rates” by Josh Alwine. The author is an engineer and statistician who evaluates data putting popular fishing theories to the test. 

One of the subjects he covered was the moon’s affect on fishing. Three different hypotheses were formed that we’ve all heard at one time or another. I thought you would all be interested to hear the results of these hypotheses put to the test.

Hypothesis number 1: The moon’s gravity affects fishing.

In the sample size of fish caught throughout the year, 7.3% of all fish were caught when the moon hit its peak gravitational impact. When the moon was at its weakest gravitational impact point, 9.0% of the fish were caught. Given the sample size the hypothesis was rejected. In this case a slightly higher number of fish were caught during the weakest gravitational point than at the strongest gravitational point. 

Hypothesis number 2: The moon’s light level affects fishing.

17% of fish caught at night were during a full moon period. 14% of fish caught at night were during a new moon period. Once again, the hypothesis is rejected. If the moon’s light had a significant impact on fishing then we’d expect the catch rates to change significantly during the two different types of moon phases.

Hypothesis number 3: Moonrise and Moonset affect fishing.

Based on the sample size with all the fish caught on any given day, 20% of fish were caught during moonrise/moonset regardless of the moon phase. However, moonrise and moonset can often go hand in hand with sunrise and sunset. In the book, the author determines that sunrise and sunset do have a significant impact on fishing. Therefore, in order to test the moonrise/moonset affects on fishing they had to test catch rates during moonrises/moonsets that occurred during the middle of the day when the sun was neither rising nor setting. When removing the sunrise/sunset factor the 20% figure mentioned earlier dropped to 13%. The catch rate of 13% mirrors the catch rate for any randomly selected hour during the day. Based on the data the hypothesis is once again rejected.

The author concludes that the moon does not significantly affect our fishing. Instead, he believes that fisherman wrongly assign meaning to moonrise/moonset when the truly impactful variable is the low light conditions that happens to coincide with these time periods. What do you guys think of these results? 

Blog content © Scott Brands
Blog Comments
SirGreg88, CO   1/14/2020 9:15:59 PM
I am not much of a hunter but I have been told by very experienced hunters that a full moon greatly affects movement and feeling. It may be pure coincidence but I have found periods of full moon coincide with very few fish being caught.
SirGreg88, CO   1/14/2020 11:01:05 PM
Feeding. Not feeling.
Hawaiian Punch, CO   1/15/2020 3:52:14 AM
I'm going with Josh Alwine and his findings . . .
Coyute, CO   1/15/2020 9:30:20 AM
Whether the moon affects fishing or not, I don't know for certain. I like thinking that it does however. That's enough for me. Besides, I have never met an engineer that was all that good at fishing. They overthink most things.
puntfish, CO   1/15/2020 9:43:06 AM
I think it also has to do with fish species. Other than night fishing for Largemouths during a full moon fishing is slow to none. Ive done my best during a new moon. I have read some of the biggest fish have been caught just after new or dark moon. I saw a show Chad Lachance always plans his trips after the new moon.
shiverfix, CO   1/15/2020 11:21:35 AM
It might be a case of expected result or single cause fallacy. If you go into a situation assuming a specific outcome it can lead to that outcome, or, there may be multiple causes for the outcome but only one is assumed to be the reason. One example, I was talking with someone last weekend about spinners. I said I don't think spinners work as well as kastmasters, but partly because I will throw a spinner for a brief time, not catch anything, and be like, see, they don't work. Then put on a kasty and use it for a significantly longer time, catch a fish, and say, see, it works better. It could be that you go out assuming a full moon is better/worse which influences how well/long you fish. I'd be curious to see where he got his data for his findings, but numbers are more accurate than anecdotal evidence.
anglerwannabe, CO   1/15/2020 11:43:18 AM
Scott, that aligns with my personal experience. I do best in low light conditions. Dawn and Dusk. But also tend to prefer slightly cloudy days. However, for LMB it doesn't seem to matter as much as cover and presentation.
Scott Brands (Skookshunter), CO   1/15/2020 12:25:39 PM
Shiverfix I'm not sure he ever says exactly where he gets his data set from. He frequently mentions that he has a large sample size. Whether this is his personal experience, external data, or a combination of the two isn't specified. He also mentions that the sample consists of different freshwater species not limited to just bass.
Swampy13, CO   1/15/2020 12:58:35 PM
There ya go......he gets his info from fishermen. Need I say more? Lol bunch of liars......
Matt, CO   1/15/2020 5:10:38 PM
Good piece Scott! I started geeking out on moon stuff a while ago. I didn't draw any good conclusions. I looked into the gravitational pull of the moon on earth and its potential effect on fish, discussed with some professors, and even started looking into ways to determine the gravitational pull in a specific location based on the moon's position and season. Didn't seem compelling enough to continue, just not strong enough. I do think visible light is a key factor. Tides obviously are a factor on very large bodies of water (oceans), those are moon gravitational pull effects. But for small inland lakes, I just can't convince myself that there's anything but a visible light effect. I want to, I just can't. I still make note of special times on muskie hunts and try to follow them. Moon overhead and underfoot - set and rise. You tend to use anything for luck when your hunting muskie!
bron, CO   1/15/2020 6:22:30 PM
We all have our own superstitions for how to increase luck in catching. For some its the moon, barometer, gear, hats, etc. I do believe post front sucks. I agree with Shiverfix...if you let one of these things get in your subconscious you will be affected by it whether you know it or not. Thats when I change hats.
Team CO.F.F., CO   1/16/2020 9:06:02 AM
Really cool! Thanks for sharing this!
Anteroman, CO   1/16/2020 9:52:29 AM
Interesting blog, I too have questioned the moon phase and it’s relationship to fish feeding. Having spent the majority of my life on salt water I can say yes, the moon affects certain fish feeding habits. A good example is the blue marlin bite off the North shore of St. Thomas, Sept/Oct/Nov a couple days in front of the full and a couple days after are almost always the most productive days of the month. Locally our wahoo bite is always best on both sides of the full moon and the months of Nov./Dec./Jan. are generally the best of the year. As far as trout go, I personally have had great days as well as mediocre days on the moon. Just go fish and keep a log, it’s still just fishing. Bill
jshanko, CO   1/16/2020 1:05:49 PM
I'm not sure how it affects fishing but I know I don't sleep well and wake early 3-5AM during a full moon. Do like early AM and late PM fishing from shore throwing jerk baits for Walleye during a full and post moon phase. Weird right.
Freestone303, CO   1/16/2020 2:18:45 PM
My wife is a teacher and adamantly argues that a full moon effects kids (negatively). Don't see why it wouldn't affect other species as well.
Smelly, CO   1/16/2020 2:52:54 PM
Not in "Total" agreement. First for the salt guys. Moon affects tide. Tide most definitely affects fishing. Obvious correlation. For us freshwater guys . Lots of theories out there. One that it works like a "porch light" at night. The fuller the moon , the brighter. The brighter. The more bugs get stirred up. That gets the baitfish in a feeding frenzy . Which does the same for the gamefish. That's one of the more plausible ones I've heard. I know that In-Fisherman has always put peak fishing at just before and just after a full moon. And they publish a moon phase table in their magazine. Myself. I think it "might " have some effect. But not enough to determine weather I go fishing or not. But I like to fish. And it really isn't imperative that I catch fish , in order to enjoy my time in the outdoors.
GoNe_FiShIn_11, CO   1/20/2020 9:13:48 AM
Thanks for sharing. That is differently an interesting read. I always tried to believe the moon was effecting the fishing but it didn’t seem to be the cause or effect for good or bad fishing. I do believe the moon effects the weather more so then the fishing. The weather has more effect on the bite then anything else. Low light times have always been the best bite times. Al least it starts a frenzy when it comes into play. I thinks it’s more about finding the fish and staying with them. Generally fish are usually willing to feed if you find them.
Ty One On, CO   1/30/2020 7:34:22 PM
All I've got to say is, paralysis by analysis. Just go fishing for God's sake....
ParkerDude, CO   2/1/2020 6:01:58 AM
Being sort of a nerd, I keep track of my fishing. In 127 day of fishing at Lake Granby during ice and open water I have caught within 1, the same average number of fish when the moon is in the brightest phases compared to when it is in the darkest phases. Lots of other variables are involved but that is the tally so far. I've had really good and bad days in both.
ondfritz80, CO   2/3/2020 2:12:47 PM
The two best times to fish are when it's raining/snowing, and when it's not.