Effects of diet and habitat on Hg levels in Japanese anchovy in the high seas of the northwestern Pacific Ocean

Long Chen; Guanyu Hu; Zhenfang Zhao; Bilin Liu; Xinjun Chen; Liling Zhang

doi:10.1016/j.marpolbul.2024.116976

Effects of diet and habitat on Hg levels in Japanese anchovy in the high seas of the northwestern Pacific Ocean

Mar Pollut Bull. 2024 Nov:208:116976. doi: 10.1016/j.marpolbul.2024.116976. Epub 2024 Sep 20.

Authors

Long Chen¹, Guanyu Hu², Zhenfang Zhao¹, Bilin Liu³, Xinjun Chen⁴, Liling Zhang¹

Affiliations

¹ College of Marine Living Resource Sciences and Management, Shanghai Ocean University, Shanghai 201306, China.
² College of Marine Living Resource Sciences and Management, Shanghai Ocean University, Shanghai 201306, China; Key Laboratory of Sustainable Exploitation of Oceanic Fisheries Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China; National Engineering Research Center for Oceanic Fisheries, Shanghai Ocean University, Shanghai 201306, China; Key Laboratory of Ocean Fisheries Exploitation, Ministry of Agriculture and Rural Affairs, Shanghai 201306, China. Electronic address: gyhu@shou.edu.cn.
³ College of Marine Living Resource Sciences and Management, Shanghai Ocean University, Shanghai 201306, China; Key Laboratory of Sustainable Exploitation of Oceanic Fisheries Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China; National Engineering Research Center for Oceanic Fisheries, Shanghai Ocean University, Shanghai 201306, China; Key Laboratory of Ocean Fisheries Exploitation, Ministry of Agriculture and Rural Affairs, Shanghai 201306, China. Electronic address: bl-liu@shou.edu.cn.
⁴ College of Marine Living Resource Sciences and Management, Shanghai Ocean University, Shanghai 201306, China; Key Laboratory of Sustainable Exploitation of Oceanic Fisheries Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China; National Engineering Research Center for Oceanic Fisheries, Shanghai Ocean University, Shanghai 201306, China; Key Laboratory of Ocean Fisheries Exploitation, Ministry of Agriculture and Rural Affairs, Shanghai 201306, China.

PMID: 39305846
DOI: 10.1016/j.marpolbul.2024.116976

Abstract

The aim of this study was to explore the effects of diet and habitat on the Hg levels of Japanese anchovy at different growth stages. We measured the amounts of Hg and stable carbon and nitrogen isotopes in the muscle and stable carbon and oxygen isotopes in the otoliths of 54 Japanese anchovy specimens obtained from the open seas of the Northwest Pacific Ocean (39°2'N ∼ 42°30'N, 154°02'E ∼ 161°29'E) between June and July 2021. Body length had a significant effect on δ¹³C_bulk, δ¹⁵N_bulk and M_oto (P < 0.01). As individuals grew, δ¹³C_bulk and δ¹⁵N_bulk tended to gradually increase, but M_oto tended to gradually decrease. The variation in the niches of Japanese anchovy at different growth stages showed that the standard ellipse-corrected area subsequently decreased with growth. It reached its smallest value in the 136-150 mm group, and there was no overlap between the 136-150 mm group and the other groups. The GAM results showed that Hg levels tended to decrease first and then increase with growth. There was a positive correlation between Hg levels and δ¹⁸O_oto in fish. Hg levels increased gradually with increasing δ¹⁵N_bulk. In our study, there may be a gradual shift in the diet of Japanese anchovy from phytoplankton to prey at higher trophic levels, and the depth of seawater in which the predators feed gradually increased with growth. Changes in diet and habitat were probably the main reasons for the increase in Hg levels.

Keywords: Hg levels; Japanese anchovy; Metabolize; Otolith; Stable isotopes.

MeSH terms

Animals
Carbon Isotopes / analysis
Diet* / veterinary
Ecosystem*
Environmental Monitoring*
Fishes*
Japan
Mercury* / analysis
Pacific Ocean
Water Pollutants, Chemical* / analysis

Substances

Carbon Isotopes
Mercury
Water Pollutants, Chemical