Shifts in the spring herring (Clupea harengus membras) larvae and related environment in the eastern Baltic Sea over the past 50 years

PLoS One. 2014 Mar 17;9(3):e91304. doi: 10.1371/journal.pone.0091304. eCollection 2014.

Abstract

Because of the high management relevance, commercial fish related aspects have often been central in marine ecosystem investigations. The iterative shiftogram method was applied to detect occurrence, type and timing of shifts in the single and multivariate time series linked to the spring spawning herring larvae in the Gulf of Riga (Baltic Sea). Altogether nineteen larval herring and related environmental variables were utilized during the period of 1957-2010. All the time series investigated, either single or multivariate, exhibited one or more shifts with variable type and timing. Multivariate shiftogram based on all time series identified two distinct states (1957-1983 and 1992-2010) in studied variables, separated by a smooth transition period lasting almost ten years. The observed shift was mainly related to hydroclimate and not to phenology or biota. Significantly increased variability was found in larval herring and recruitment abundances after the shift. While the shift in hydroclimate (1985-1991) was followed by the shift in phenology (1991-1997), the shift in biota occurred remarkably later (2003). It is likely that the dynamics in biota were affected by other drivers than those investigated in the current paper.

MeSH terms

  • Algorithms
  • Animals
  • Baltic States
  • Biota
  • Climate
  • Cluster Analysis
  • Ecosystem*
  • Fishes*
  • Larva*
  • Models, Theoretical
  • Oceans and Seas*
  • Population Density
  • Population Dynamics

Grants and funding

This work was partially financed by the Estonian Ministry of Education and Research (grantSF0180005s10), Institutional research funding IUT02-20 of the Estonian Research Council and by the Estonian Science Foundation (grants 8254, 8747). The research leading to these results has also received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under Grant Agreement No. 266445 for the project Vectors of Change in Oceans and Seas Marine Life, Impact on Economic Sectors (VECTORS). The study has been supported by the project on The status of marine biodiversity and its potential futures in the Estonian coastal sea 3.2.0802.11-0029 of Environmental protection and – technology programme of European Regional Fund. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.