Is a rapid expansion of the invasive amphipod Gammarus tigrinus Sexton, 1939 associated with its niche selection: a case study in the Gulf of Finland, the Baltic Sea

Jonne Kotta,Maiju Lehtiniemi,Vadim Panov,Merli Pärnoja,Stanislaw Malavin,Greta Reisalu,Tarja Katajisto

doi:10.3391/ai.2013.8.3.08

Abstract

Among the recent non-indigenous species the gammarid amphipod Gammarus tigrinus is one of the more aggressive invaders in the Baltic Sea. Quantitative sampling of the shallow water habitats of the Gulf of Finland showed that G. tigrinus has become established in the whole coastal zone of the Gulf. Boosted Regression Trees modelling indicated that the abundance and biomass of G. tigrinus varied as a function of wave exposure, water salinity and transparency, with the invasive amphipod having higher abundance and biomass at less exposed, more dilute, and more turbid sites. Gammarus tigrinus appears to be competitively superior to the native gammarids, possibly leading to further decline of the native gammarid populations in the Gulf of Finland.

Highlights

The Baltic Sea, especially in its northern portion, has witnessed an unprecedented increase in the number of biological invasions
Boosted Regression Trees modelling indicated that the abundance and biomass of G. tigrinus varied as a function of wave exposure, water salinity and transparency, with the invasive amphipod having higher abundance and biomass at less exposed, more dilute, and more turbid sites
Native amphipods were represented by mud shrimp Corophium volutator (Pallas, 1766) and five species of gammarid amphipods: Gammarus zaddachi Sexton, 1912, Gammarus duebeni Liljeborg, 1852, Gammarus salinus Spooner, 1947, Gammarus oceanicus Segerstråle, 1947 and Gammarus pulex Linnaeus, 1758

Summary

Introduction

The Baltic Sea, especially in its northern portion, has witnessed an unprecedented increase in the number of biological invasions. All the species have rapidly increased their population densities, expanded their distribution area, and formed permanent populations (Berezina 2007; Packalén et al 2008; Herkül et al 2009; Kotta and Kuprijanov 2012; Kotta and Ojaveer 2012; Katajisto et al 2013). Milne-Edwards, 1853) and some other non-indigenous species appear to have increased in abundance in recent years in the northeastern part of the Baltic Sea Such invasions have been shown to trigger major shifts in benthic and pelagic communities (e.g. Kotta et al 2004; Kotta et al 2006; Põllumäe et al 2007; Ojaveer et al 2011)

Methods

Results

Conclusion