Monthly Change in Food Size of Larval Walleye Pollock <i>Theragra chalcogramma</i> at the Initial Feeding Stage in Funka Bay and Surrounding Vicinity in Hokkaido

• Nakatani Toshikuni

  Faculty of Fisheries, Hokkaido University

Bibliographic Information

Other Title

• Monthly Changes in Food Size of Larval Walleye Pollock Theragra chalcogramma at the Initial Feeding Stage in Funka Bay and Surrounding Vicinity in Hokkaido
• Monthly Changes in Food Size of Larval
• Monthly change in food size of larval walleye pollock Theragra chalcogramma at the initial feeding stage in Funka Bay and surrounding vicinity in Hokkaido

Abstract

Larvae of walleye pollock Theragra chalcogramma were collected by vertical haulsfrom the sea bottom to the surface with a NORPAC net from January to March 1991 in Funka Bay and surrounding vicinity in Hokkaido. Larvae were abundant in January and decreased in February and March. To clarify the food availability of walleye pollock larvae at the initial feeding stage, the size of food for larvae smaller than 7mm in total length (TL) were measured. The total length of larvae collected in January ranged from 4.2 to 6.5mm. Most of 4.2-5.1mm TL larvae had empty stomachs. Food organisms were found from 7 larvae (4.8-6.5mm TL). Among them, copepod nauplii were dominated (60.5%), followed by invertebrate eggs (25.6%) and copepodids (13.9%). The body width of Oithona nauplii in the stomachs ranged from 84 to 121 μm and Paracalanus nauplius was 103 μm. Larvae of 4.0 to 13.2mm TL were collected in February. Six larvae (<7.0mm TL) fed on copepod nauplii (67.6%), invertebrate eggs (20.6%), copepodids (8.8%), and diatom Coscinodiscus sp. (3.0%). Copepod nauplii in the stomachs were larger than 95 μm in width. In March, food organisms taken by 5 larvae (<7mm TL) consisted of copepod nauplii (54.5%), invertebrate eggs (36.4%), and copepodids (9.1%). The width of copepod nauplii in the stomachs ranged from 156 to 176 μm. From these observations, it is considered that the primary food items of larval walleye pollock at the initial feeding stage are largesized copepod nauplii (>84 μm) in this area.

Journal

• Fisheries science

  Fisheries science 61 (3), 387-390, 1995

  The Japanese Society of Fisheries Science

Keywords

• walleye pollock
• Theragra chalcogramma
• larvae
• food size
• Funka Bay
• copepod nauplii
• Oithona
• Pseudocalanus
• Metridia

Details

• CRID: 1390001204430382336
• NII Article ID: 130003902685
• NII Article ID: 10004861960
• NII Book ID: AA10993718
• DOI: 10.2331/fishsci.61.387
• NDL BIB ID: 3644313
• ISSN: 09199268
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I3644313
• Web Site: https://www.jstage.jst.go.jp/article/fishsci1994/61/3/61_3_387/_pdf
• Text Lang: en
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
• Abstract License Flag: Disallowed