Trophic ecology of icefishes (Notothenioidei, Perciformes) in a context of climate change

Quentin Peignot

1

_{, Bruno Frédérich}

1,2

_{, Gilles Lepoint}

1

_{and Loïc N. Michel}

1,3

1_{Laboratory of Oceanology, MARE Centre, University of Liège, B6c, 4000 Liège, Belgium.} 2_{Laboratory of Functional and Evolutionary}

Morphology, AFFISH Research Centre, University of Liège, B6c, 4000 Liège, Belgium. 3_{Deep-Sea Environments Laboratory (LEP), Ifremer}

Bretagne Centre, 29280 Plouzané, France

2002/ 20 04 δ 1 5N ‰

Trophic ecology of icefishes (Notothenioidei, Perciforms) in a context of climate

change: focus on two widespread genera (Lepidonotothen and Trematomus)

o Southern Ocean (SO) undergoes major

environmental modifications (changes in sea ice cover, temperature, pH, …)

o _{Icefishes (Notothenioidei) living in the SO can exploit}

various ecological niches and are an important component of food webs

How will two widespread genera of icefishes react to environmental changes? Will it influence their ecology, and notably resources partitioning?

o Lepidonotothen and Trematomus sampling in Weddell and Scotia seas during RV Polarstern campaigns of 2002-04 and 2015-16

o Use of stable isotopes ratios of carbon (δ13_{C) and}

nitrogen (δ15_{N) to build isotopic niches (proxies of}

realized ecological niches)

Icebreaker “RV Polastern” of the AWI

Discussion and conclusion

o _{Great variation in isotopic compositions among icefishes: they exploit a wide}

array of resources, especially Trematomus.

o _{Temporal evolution of niches: taxon-specific ecological plasticity in}

response to variation in environmental parameters and/or prey availability.

o _{Over time: decrease of the amounts of resources exploited by Trematomus}

and of the overlap between niches of the two genera. Result of past

competition?

Introduction

Methods

Results

Lepidonotothen 2002/2004 Lepidonotothen 2015/2016 Trematomus 2002/2004 Trematomus 2015/2016

Overlap of isotopic niches in 2002/2004 between the genera Jointly exploitation of resources?

In 2002/2004: SEA of Trematomus is larger than the one of

Lepidonotothen More exploited resources

Acknowledgments

We thank members of Polarstern expeditions XIX/5, XXI/2 and ANT-XXXI/2 (particularly H. Christiansen, KU Leuven). This work is part of the vERSO and RECTO

projects (https://rectoversoprojects.be), funded by the Belgian Science Policy Office

(BELSPO).

2015/

20

16

Taxon-specific ecological plasticity (e.g. T. Lepidorhinus) Iso to pi c n ic he s B ay e si an m o de l o f 10 5 e st im at e s δ13_{C ‰} δ 1 5N ‰ δ 1 5N ‰ 99,9% M o de l-e st im at e d S tan da rd E ll ips e Ar e a ‰ ² δ13_{C ‰}

Temporal variation of isotopic composition depends on the considered species