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Pelagic ecosystem monitoring of the key species of Middle Trophic Level in the Ross Sea

Istituto per le Risorse Biologiche e le Biotecnologie Marine (CNR-IRBIM) Ancona - ITALY

Iole Leonori, Andrea De Felice, Ilaria Biagiotti, Giovanni Canduci, Ilaria Costantini, Giordano Giuliani

Workshop “Oceano Antartide”Oltre 30 anni di ricerche oceanografiche in Antartide: Risultati e Prospettive

4-5 luglio 2019

Acoustic surveys by CNR IRBIM were carried out in the Ross Sea in the ambit of PNRA - Italian National

Programme for Research in Antarctica- expeditions, in:

1989/90, 1994/95, 1997/98, 1999/00, 2003/04, 2013/14 and 2015/16

January 2004 January 2014 January 2016

Ross Ice Shelf

Target species

Antarctic Krill (Euphausia superba)

Antarctic silverfish

(Pleuragrammaantarctica)

Ice Krill (Euphausia crystallorophias)

Acoustic surveys are a standard to provide apicture of the marine ecosystem comparableover time

in such a way that allow to the stakeholders anevaluation of the ecological status, spatialadequacy, and effectiveness of on the recentlyestablished Ross Sea Marine Protected Area.

Trophic web in the Ross SeaMPA research and monitoringplan topics:

- Trends in Antarctic krill, crystalkrill, and Antarctic silverfishpopulations and demographicprocesses in relation to physicaldrivers, climate change, andpossible fishery effects.

- Effects of changes in theavailabilities of these specieson their respective predators.

Priority elements for ecosystemresearch:

- Acoustic surveys to mapdistribution and abundance ofAntarctic silverfish and krill.

Acoustic sampling

Euphausia superba superswarms near ice edge

Pelagic net sampling

E. superba swarm (left) and E. crystallorophias swarms (right) sampled by pelagic trawl. Headline and footrope positions in evidence in the echograms.

Biological measurements

Oceanographic sampling

Oceanographic sampling is made incooperation with researchers from CNRIRBIM of Ancona and UniversitàParthenope of Naples in order to haveinformation on water massescharacteristics (CTD, XBT).

• Inverse correlation between E. superba density and salinity in the water column

• Positive correlation between E. crystallorophias abundance and fluorescence

New project: ROSSKRILL - Pelagic ecosystem monitoring of the key species of Middle Trophic Level in the Ross Sea Marine Protected Area

• Acoustic survey to be conducted during austral summer 2019-20 (or 2020-21 depending on installationof basic instruments on the new research vessel «Laura Bassi»), over a big portion of the recentlyinstituted MPA

• Hopefully at a larger scale than 2014 and 2016 surveys, similar to older surveys in the area (1994-2004); see figure below

• Installation of a SIMRAD WBAT operating for around one year at 70 and 120 kHz on Mooring B of the Marine Observatory of the Ross Sea to monitor seasonal local changes in krill abundance also in relation with ice formation and melting

Thanks for your attention