Solunar tables say fish bite best around the new and full moon. NOAA interviews saltwater anglers at the dock as they finish fishing, about 86,000 trips a year, and records what they caught. I checked the moon against 1.4 million of those trips.
Trips near the new and full moon caught fish at 0.999 times the rate of trips near the quarter moons. The 95% interval runs from 0.980 to 1.018, so whatever the moon does, it's under 2% either way. That's 730,635 trips from 2015 to 2025. The same test on another 654,580 trips from 2005 to 2014 came out at 0.998.
In fish
An average trip caught 1.85 fish an hour, about 7 in four hours. Moving from a quarter moon to a new or full moon changed that by 0.01 fish per four-hour trip, with an interval from 0.15 fewer to 0.13 more. 69% of trips caught at least one fish, and the moon moved that share by 0.05 percentage points.
How the test worked
I wrote the method down before opening the data. Each trip is compared only with trips at the same spot, in the same month and year, fishing the same way: from shore, a private boat, a charter or a headboat. That takes out where and when people fish. Catch counts every fish kept or released, per hour fished.
The windows are two days either side of each moon phase. The intervals come from resampling whole days, because everyone fishing on a given day shares the same moon.
Checks
| Run | Trips | New and full vs quarter | 95% interval |
|---|---|---|---|
| 2015-2025, as planned | 730,635 | 0.999 | 0.980 to 1.018 |
| 2005-2014 | 654,580 | 0.998 | 0.978 to 1.017 |
| Easter weekends dropped | 722,979 | 0.997 | 0.979 to 1.018 |
| NOAA survey weights | 730,635 | 1.010 | 0.982 to 1.035 |
| New England | 140,187 | 0.977 | 0.947 to 1.013 |
| Mid-Atlantic | 183,912 | 1.010 | 0.980 to 1.041 |
| South Atlantic | 237,823 | 0.983 | 0.957 to 1.011 |
| Gulf | 146,600 | 1.024 | 0.975 to 1.073 |
| Hawaii | 19,896 | 0.994 | 0.862 to 1.125 |
| Shore | 177,078 | 1.034 | 0.992 to 1.076 |
| Private boat | 364,755 | 0.989 | 0.964 to 1.017 |
| Charter | 138,290 | 1.002 | 0.976 to 1.031 |
| Headboat | 50,512 | 0.999 | 0.931 to 1.068 |
Easter falls on the Sunday after the first full moon of spring, so one busy holiday weekend a year lines up with a full moon. Dropping those weekends changed nothing. Taken one year at a time, 2018 came out above 1 (1.081) and the other ten years didn't, which is about what chance gives across eleven tries.
What this can't tell
- Whether more people go fishing around a full moon. Interview counts follow NOAA's sampling schedule.
- The hour-by-hour feeding periods solunar tables also print. Moon phase here is a daily value.
- One species at a time. This counts all fish together. A Gulf study found moon effects in red grouper and tilefish and none in red snapper (Pulver, 2017).
- Texas, the West Coast and Alaska, which run their own surveys. The 2015-2025 data covers 17 states, Maine to Mississippi plus Hawaii.
Data: NOAA Fisheries, Marine Recreational Information Program, Access Point Angler Intercept Survey, public trip and catch files, 2005 to 2025. Moon phase from Meeus, Astronomical Algorithms, checked against published new and full moon dates.