Current status of natural spawning of chum salmon Oncorhynchus keta in rivers with or without hatchery stocking on the Japan Sea side of northern Honshu, Japan

Masaya Iida, Kunimasa Yoshino, Satoshi Katayama

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Information on the status of natural spawning is needed on the Japan Sea side of northern Honshu, Japan for ecosystem-based sustainable management of chum salmon resources. We conducted on-site visual surveys in October–December of 2015 and 2016 that targeted spawning chum salmon redds in all rivers > 5 km long (total 94 rivers) in Akita, Yamagata, Niigata (including Sado Island), and Toyama prefectures. The ratio of rivers found to host natural reproduction to the total number of surveyed rivers was 93.6% (44/47) in stocked rivers and 74.5% (35/47) in non-stocked rivers. These results show that there is a wide occurrence of natural reproduction of chum salmon in these rivers, regardless of the history of hatchery stocking. The density of spawning redds (number of redds/1000 m 2 ) as an indicator of chum salmon escapements did not differ (P = 0.54) between stocked rivers (mean 3.5, N = 49) and non-stocked rivers (mean 2.4, N = 36),when rivers where no redds were observed were excluded from the analysis. These results suggest that chum salmon escapements into non-stocked rivers may not be negligible. Conservation measures for wild fish are needed in stocked and non-stocked rivers to promote enhancement programs based on natural reproduction.

Original languageEnglish
Pages (from-to)453-459
Number of pages7
JournalFisheries Science
Volume84
Issue number3
DOIs
Publication statusPublished - 2018 May 1

Keywords

  • Chum salmon
  • Escapement
  • Hatchery program
  • Natural spawning
  • Northern Honshu
  • Wild fish

ASJC Scopus subject areas

  • Aquatic Science

Fingerprint Dive into the research topics of 'Current status of natural spawning of chum salmon Oncorhynchus keta in rivers with or without hatchery stocking on the Japan Sea side of northern Honshu, Japan'. Together they form a unique fingerprint.

Cite this