Do Moon Phase and Tides Affect Catches? Inconclusive on Current Data

The earlier "no lunar cycle" finding is withdrawn. In the 2026-09-26 snapshot, 14,328 catches with a verified moon age span 612 days and 3,531 anglers, but there is no record of effort or blank trips, and the cycle tests and power analysis have not been rerun on this cohort. Whether moon phase or tides matter is currently inconclusive.

Inconclusive: the data hold successful catches only, with no effort or blank-trip records, and the earlier cycle test has not been rerun on the current data.

Reviewed 2026-09-29 | Data 2025-01-01 to 2026-09-25

The earlier version tested daily catch series from 2025-01-01 to 2026-09-04 for cycles, reported no lunar or spring-tide cycle, and gave a lower bound on the detectable cycle size. That conclusion is withdrawn.

There are three reasons. The data hold successful catches only, with no effort, fishing time or blank trips, so a real cycle could be masked or exaggerated by changes in effort. Under the current data integrity rules the usable records changed from 30,216 to 14,328, and the earlier tests and power analysis have not been rerun on them. The tide-phase comparison covers only 4,187 marine records whose location or capture time comes from the photo.

So whether moon phase or tides matter is currently inconclusive. This is neither a finding of no effect nor a finding of an effect.

In the 2026-09-26 snapshot, 14,328 eligible catches from 2025-01-01 to 2026-09-25 have a verified moon age. They span 612 days, 3,531 anglers and 10,399 angler-days.

By water class: marine 6,239 (575 days, 1,998 anglers), freshwater 7,933 (573 days, 2,155 anglers), unknown 156. Water class is used only for grouping; no record was excluded because of it.

Of 4,187 marine records whose tide data passed the integrity check and whose location or capture time comes from the photo, 2,241 (54%) fall on a rising tide and 1,946 (46%) on a falling tide; 2,176 are from estuaries and 2,011 from the coast.

These count where successful catches fell. Without fishing time per tide phase they cannot say which phase fishes better.

The time and outcome of every trip, including trips with no catch, so each day has an effort denominator.

A rerun of the daily-series cycle tests, permutation inference and power analysis on a fixed snapshot, with the hypotheses written down before looking at the data.

Source: a read-only point-in-time snapshot taken 2026-09-26 (38,040 catch records), recomputed offline with no production reads or writes.

Records count when the current record, species identity and context rules all pass and both upload and verified capture time are on or before 2026-09-25; shrimp-fishing, managed-pond and non-fish records are excluded. Moon age and tide phase count only when the app's environment integrity check verifies them.

A separate page lists moon-phase report counts for each species; it is also a descriptive distribution.