North Pacific Anadromous Fish Commission

Technical Report 17

Table of Contents

Analysis of Temperature Tolerance in Juvenile Chum Salmon (Oncorhynchus keta)

Authors: 
Muhammad Nurul Fajri, Takuto Ouchi, Yoshio Takei, Susumu Hyodo, and Makoto Kusakabe

Abstract Excerpt:
An increase in seawater temperature as a consequence of global climate change will inevitably adversely affect aquatic organisms. The impact may be severe for stenothermal species with a limited temperature range inhabiting cold-water environments, such as salmonids. In this study, we analyzed the temperature tolerance of early-return and late-return chum salmon in Iwate Prefecture, Japan (Fig. 1). The early-return chum salmon initiate their return migration to natal rivers in late September to early October, when the sea surface temperature (SST) is around 20°C, and most late-return populations come back in December when the SST is lower than 16°C. Thus, temperature tolerance may differ between those two groups. At the cellular level, heat stress may result in protein unfolding and thus impact biochemical functions. Heat-impacted cells may respond in two non-exclusive ways: proteolysis or protein degradation by proteasomes, and/or protein re-folding by chaperone proteins such as heat shock proteins (HSPs) (Iwama et al. 1999). HSPs are chaperone proteins that are produced by cells as a reaction to stressors. While their main function is the refolding of damaged proteins, some HSPs also play important roles incorrectly folding newly synthesized proteins (Ito and Nagata 2019). Thus, the HSPs are critical components for survival during physiological stress. To analyze the difference in the temperature tolerance between the populations of early- and late-returning chum salmon, we compared survival rates and transcript levels of HSPs among the different populations of chum salmon exposed to elevated temperatures.

*This is the first paragraph of an extended abstract. Download the full abstract below.

DOI:
https://doi.org/10.23849/npafctr17/35.37.

Citation

Fajri, M.N., T. Ouchi, Y. Takei, S. Hyodo, and M. Kusakabe.  2021.  Analysis of temperature tolerance in juvenile chum salmon (Oncorhynchus keta).  N. Pac. Anadr. Fish Comm. Tech. Rep. 17: 35–37.  https://doi.org/10.23849/npafctr17/35.37.