Is the Bite Better at Dawn and Dusk? Within-Trip Rates Are Inconclusive on Current Data

The earlier finding from 1,185 trips that twilight bite rates are no higher than midday is withdrawn. In the 2026-09-26 snapshot only 537 trips have integrity-verified sun position and meet the trip rule (one angler, one day, at least 3 catches, first to last at least one hour apart); the within-trip exposure bins and permutation test have not been rebuilt, and trips with no catch or only one or two catches never enter the denominator. Whether dawn and dusk fish better is currently inconclusive.

Inconclusive: only 537 usable trips, 184 of them with photo capture times, and the within-trip test has not been rerun on this cohort.

Reviewed 2026-09-30 | Data 2025-01-01 to 2026-09-25

The earlier version treated the time between an angler's first and last catch of a day as time spent fishing, binned 1,185 trips (5,658 hours) from 2025-01-01 to 2026-09-04 by sun altitude, and concluded that twilight bite rates are no higher than midday. That conclusion is withdrawn.

There are three reasons. Under the current integrity rules the usable trips changed from 1,185 to 537, and photo-timed trips from 422 to 184; the sun-altitude exposure bins and permutation test have not been rebuilt on them. Only trips with at least 3 catches spanning an hour or more enter the denominator, so trips with no catch or one or two catches are invisible. The data do not record whether the angler kept fishing between the first and last catch.

So whether dawn and dusk fish better is currently inconclusive. This is neither a finding of no difference nor a finding that twilight is better.

Of 14,424 eligible catches from 2025-01-01 to 2026-09-25, 14,328 have an integrity-verified sun position.

537 trips meet the rule (302 anglers, 214 days) with 2,442 catches; excluding each trip's first and last catch leaves 1,368 within-trip catches over 1,872 hours between first and last.

Using photo capture times only: 184 trips (119 anglers, 64 days), 492 within-trip catches over 612.9 hours.

The start and end time of every trip, and trips with no catch, so the denominator is not limited to productive trips.

Sun-altitude exposure bins rebuilt on a fixed snapshot, hypotheses written down before looking at the data, then a rerun of the permutation test and power analysis.

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. Sun position counts only when the app's environment integrity check verifies it.

A trip is one angler on one Taipei date with at least 3 catches whose first and last are at least one hour apart.