How Did the Late 1980s Climate Regime Shift Affect Temperature-Sensitive Fish Population Dynamics: Case Study of Vendace (Coregonus albula) in a Large North-Temperate Lake

Külli Kangur,Andu Kangur,Tõnu Möls,Peeter Kangur,Kai Ginter

doi:10.3390/w12102694

Abstract

The population dynamics of fish in northern lakes is strongly influenced by climatic factors. In this study, we investigated whether there is a link between the late 1980s climate regime shift in Europe and the collapse of vendace (Coregonus albula) population at the same time in Lake Peipsi. Until the end of the 1980s, vendace was very abundant in the lake, but then its catches sharply declined. This decline inspired investigations into the extreme weather events preceding the vendace collapse using data on daily water temperatures and ice phenology together with commercial fishery statistics since 1931 and test catch data since 1986. We identified using advanced statistical methods that the hot summer of 1988, which was accompanied by a severe cyanobacterial bloom and extensive fish kill, and the subsequent non-permanent ice cover and early ice-offs in 1989 and 1990 in Lake Peipsi were the main reasons for the disappearance of vendace from catches in 1991. Moreover, a negative correlation appeared between catches of the predatory pikeperch (Sander lucioperca) and vendace. Predation pressure as well as fish habitat degradation caused by lake eutrophication may contribute to the instability of the vendace population too. Our study showed that extreme weather events such as heat waves in summer and non-permanent ice-cover in winter in consecutive years may have long-lasting harmful effects on the population abundance of cool-water fish species such as vendace whose eggs usually develop under an ice cover in north-temperate lakes.

Highlights

Declines and collapses of fish populations have frequently been attributed to local human interventions, including over-exploitation of fisheries [1,2,3,4] and habitat loss due to pollution [5].predator–prey interactions [6], parasite infections [7] and climate can trigger the reduction of fish species
The results of our study provide strong evidence of a link between a sudden collapse of vendace in Lake Peipsi in the late 1980s and a regional climate regime shift [13,49] which manifested itself in Estonia with a sharp warming in the late 1980s, mainly from the winter of 1988/1989 with coherent shift in air temperature, snow cover duration and specific runoff [48]
We show that extreme weather events in summer and winter in consecutive years may have long-lasting harmful effects on the population abundance of cool-stenothermal and oxygen-demanding fish species such as vendace in large shallow lakes in the north temperate region

Summary

Introduction

Declines and collapses of fish populations have frequently been attributed to local human interventions, including over-exploitation of fisheries [1,2,3,4] and habitat loss due to pollution [5]. Predator–prey interactions [6], parasite infections [7] and climate can trigger the reduction of fish species. Decline and collapse of fish populations at different geographical scales have been widely reported in recent decades [2,9,14]. In Europe’s fourth largest lake, Lake Peipsi (Estonia/Russia), vendace (Coregonus albula) was the dominant fish species and the main target of commercial fishery until the end

Results

Discussion

Conclusion