Do Anglers Release Invasive Fish? Inconclusive on Current Data

The earlier finding from 17,305 freshwater catches, that release follows fishing-method habit and hardly depends on invasive status, is withdrawn. In the 2026-09-26 snapshot, 7,957 eligible freshwater catches record whether the fish was released, and 6,150 (77%) were; but the snapshot has no verified invasive-species classification, so any difference between invasive and native species is currently inconclusive.

Inconclusive: the pinned snapshot's species catalogue has no invasive classification and the external list the earlier study used was never pinned, so invasive and native release cannot be compared.

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

The earlier version compared release of invasive and native species in 17,305 freshwater catches from 3,836 anglers (2025-01-01 to 2026-09-04) and concluded that release follows fishing-method habit and hardly depends on invasive status. That conclusion is withdrawn.

There are two reasons. The pinned species catalogue (3,479 rows) has no invasive or native field, and the external list the earlier study used was never pinned with the data, so the comparison cannot be rebuilt. Under the current integrity rules the counted records differ, and the earlier within-angler model has not been rebuilt on them.

So whether invasive and native species are released differently is currently inconclusive. This is neither a finding of no difference nor a finding of a difference.

From 2025-01-01 to 2026-09-25 there are 14,424 eligible catches. By water class, over catches that record release: freshwater 7,957, of which 6,150 released (77%) and 1,807 kept, plus 21 unrecorded, from 2,165 anglers; marine 6,276, of which 3,459 released (55%) and 2,817 kept, plus 11 unrecorded, from 2,009 anglers.

This is the distribution of release records in site catches, not the release behaviour of all anglers in Taiwan; there is no effort or unsuccessful-trip record, so it says nothing about fishing conditions.

A versioned invasive-species list that can be pinned and mapped species by species to the site's species identity, with its source and date recorded.

Hypotheses written down before looking at the data, then a rebuilt within-angler comparison on a fixed snapshot.

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 from 2025-01-01 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. Water class is used only for grouping; no record was excluded because of it.