Temporal variability in mortality and recruitment jointly influence the periodic fluctuations in Antarctic krill populations

Sisong Dong; Fan Zhang; Guoping Zhu

doi:10.1016/j.marenvres.2024.106923

Temporal variability in mortality and recruitment jointly influence the periodic fluctuations in Antarctic krill populations

Mar Environ Res. 2024 Dec 21:204:106923. doi: 10.1016/j.marenvres.2024.106923. Online ahead of print.

Authors

Sisong Dong¹, Fan Zhang², Guoping Zhu³

Affiliations

¹ College of Marine Living Resource Sciences and Management, Shanghai Ocean University, Shanghai 201306, China; Center for Polar Research, Shanghai Ocean University, Shanghai 201306, China.
² College of Marine Living Resource Sciences and Management, Shanghai Ocean University, Shanghai 201306, China; National Engineering Research Center for Oceanic Fisheries, Shanghai 201306, China.
³ College of Marine Living Resource Sciences and Management, Shanghai Ocean University, Shanghai 201306, China; Center for Polar Research, Shanghai Ocean University, Shanghai 201306, China; Polar Marine Ecosystem Group, The Key Laboratory of Sustainable Exploitation of Oceanic Fisheries Resources, Ministry of Education, Shanghai 201306, China; National Engineering Research Center for Oceanic Fisheries, Shanghai 201306, China. Electronic address: gpzhu@shou.edu.cn.

PMID: 39724803
DOI: 10.1016/j.marenvres.2024.106923

Abstract

Antarctic krill (Euphausia superba) is a key part of the food web in the Southern Ocean ecosystem. Significant inter-annual fluctuations in population dynamics make stock assessment and management of its population a significant challenge. To better understand the population dynamics and fluctuation of krill, a survey-based age-structured catch-at-length model (ACL) is used to estimate the periodic fluctuations, based on length data collected from scientific surveys under the US Antarctic Marine Living Resources (AMLR) Program between 1992 and 2011. Spectral analysis of the model estimates revealed periodic fluctuations of 5-6 years in the recruitment, total abundance, and total biomass of krill in the Antarctic Peninsula, while spawning stock biomass exhibited periodic fluctuations of both 5-6 years and 2-3 years. The variations in krill total abundance and total biomass were mainly driven by recruitment, but the variation in spawning stock biomass was likely driven by both recruitment and time-varying, age-specific mortality. Our study contributes to a better understanding of the patterns and drivers of the periodic dynamics of Antarctic krill, which may help lead to improved assessments and fishery management for this important stock.

Keywords: Age-structured catch-at-length model; Antarctic krill; Fisheries management; Periodic fluctuation; Population dynamics.