open access

https://hdl.handle.net/2115/62326

Annual variation in otolith increment widths of walleye pollock (Gadus chalcogrammus) larvae in Funka Bay, Hokkaido, Japan

英語

walleye pollock

2015-07-01

Fisheries Oceanography

24(4)

325-334

To clarify relationships between year-class strength and larval growth of walleye pollock (Gadus chalcogrammus), and oceanographic conditions in the Pacific stock off Hokkaido and Tohoku, Japan, we undertook CTD observations and investigated larval densities, larval otolith increment widths, and larval prey densities (of copepod nauplii) of the 2008, 2009, 2010, and 2011 year classes in Funka Bay. Oyashio Coastal Water (OCW) flowed into the bay in late February in 2008, 2010, and 2011, and mean water temperatures decreased to 1.9–3.1 °C in March. OCW was not observed in 2009, and it was warm in late February (≥ 3.4 °C). Increment widths of lapillar otoliths during the yolk-sac stage were wide in 2009 and 2011, medium in 2010, and narrow in 2008. Increment widths during the first-feeding stage tended to become wider as the hatch month progressed, and the annual variation during the first-feeding stage was larger than that of the yolk-sac stage. The densities of the primary food for the larvae were high in 2008 when larval increment widths were narrowest, so the effect of prey abundance on larval growth appeared to be small. The ranking of the larval abundance in March was nearly coincident with that of the increment width during the larval stage. We therefore suggest that larval growth rate is associated with mortality rate, and that the growth–mortality hypothesis may be applicable to walleye pollock in Funka Bay. Feeding success under warm water conditions may be an important factor that contributes towards high growth rates.

学術雑誌論文

Accepted Manuscript

This is the peer reviewed version of the following article: Yota Kano et al. (2015), Annual variation in otolith increment widths of walleye pollock (Gadus chalcogrammus) larvae in Funka Bay, Hokkaido, Japan. Fisheries Oceanography, 24:4, 325-334. doi:10.1111/fog.12111, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1111/fog.12111.This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.

1054-6006

1365-2419

AA10913810