A brief overview of cetacean acoustic monitoring

along the west coast of Ireland

Marine Acoustics Workshop

7th February, 2018

Dr. Joanne O’Brien

Marine and Freshwater Research Centre

(Berrow, S.D., Wall, D., Benhemma, A., Carmen, M. and Meade, R.)

Overview of Static Acoustic Monitoring

• What is Static Acoustic Monitoring (SAM)

• Devices used in Irish waters

• Types of analyses carried out

• Results from three key projects

• Case study 1 - Shannon Estuary

• Case study 2 - MRE test site, Spiddal

• Case study 3 - ObSERVE-acoustic

Mullet peninsula(2009-2012)

Connemara (2003)

Galway Bay(2005-2017)

Shannon Estuary(2001-present)

Blasket Islands(2007-2011)

Roaringwater Bay (2007, 2008, 2015)

Dublin Bay

(2008 - present)

Cork Coast (2008) Cork Harbour (2010, 2011)

Portrush, Co Antrim

(2014-15)

Offshore Coverage

Case study 1 – The Shannon Estuary

Shannon Estuary

Special Area of Conservation

Important industrial area

©Simon Berrow

C-POD Deployment

Location Monitoring Period Days Monitored

Moneypoint 2009 – Present

1, 920

Foynes 2009 – Present 1,628

Auginish 2011 – Present 912

Shannon Airport 2011 – Present 938

Tarbert 2011-2017 500

Seasonal Foraging

Tidal Foraging (Tidal Phase)

Case Study 2 – MRE Test Site Spiddal

© SMARTBAY

Monitoring period: May 2006 – June

2016

967 days 29,145 sixty-minute logging

hours

Harbour porpoise presence

✓ 89.2% of days monitored

✓ 17% of hours monitored

Consistent and high over the long-term

Year# days

monitored

Total porpoise

detections

% of days with porpoise detections

2006 164 161 98.2

2007 74 47 63.5

2009 263 246 93.5

2010 252 225 89.3

2014 127 105 82.7

2015 25 22 88.0

2016 62 57 91.9

Total 967 863 89.2

SAM & WEC deployment

BEFORE

DURING

AFTER

Seasonal distribution and foraging behaviour of harbour

porpoise at the MRE Test site

1) Harbour porpoise occurrence

between 2006 and 2016

2) Foraging behaviour

between 2009 and 2016

* * *

*: statistically significant

Effects of Wave Energy Converters on harbour

porpoise occurrence and foraging behaviour

*: statistically significant

*

Negative effects? Disturbance

Harbour porpoise responses:

Avoidance behaviour? Displacement?

Positive effects: Fish aggregation platform?

Negative effects: Disturbance?

/!\ At a commercial scale: WEC off periods

rare

1) Harbour porpoise occurrence between 2006 and 2016

2) Foraging behaviourbetween 2009 and 2016

**

*

NS

NS

Benhemma le galle, A. and O’Brien, J. (In prep)

Vessels – PAM and SAM

deploymentsPAM SAM

SAM- CPODs

Funded by

Case study 3 – ObSERVE-

acoustic

Study Area

Static Acoustic Monitoring

• Each AMAR was in a glass sphere with an

acoustic release and beacon for retrieval.

• Each AMAR was fitted with an HTI-99-HF

omnidirectional hydrophone (High Tech Inc.,

−164 dB re 1 V/μPa sensitivity).

• Data were sampled at 32 ksps during 342 s

and at 250 ksps during 130 s every 8 min.

• The 32 ksps channel had 24-bit resolution

with a spectral noise floor of 29 dB re 1

μPa2/Hz and a nominal ceiling of 165 dB re 1

μPa.

• The 250 ksps channel had 16-bit resolution

with a spectral noise floor of 35 dB re 1

μPa2/Hz and a nominal ceiling of 171 dB re 1

μPa.

Partners in ObSERVE-Acoustic

Fin whale - Occurrence and Distribution

– 174,295 calls

• 53% in 2015

• 47% in 2016

– Detections higher in the north from

September to December

– Reduction in late spring and

summer consistent with known

seasonality of songs

2015

2016

Partners in ObSERVE-Acoustic

– Number of calls per day varied significantly

with month, season and mooring

– There was significantly more detections

during night-time hours

Fin Whale - Abundance per Zone and Season

Partners in ObSERVE-Acoustic

– 1,624,871 clicks recorded

• 64.4% in 2015

• 35.6% in 2016

– Detected on all moorings in all seasons

– Detections higher at moorings surrounding

the Porcupine Bank

Sperm whale - Occurrence and Distribution

2015

2016

Partners in ObSERVE-Acoustic

– Detection rates lower at moorings 7 and 8 in all

seasons.

– Moorings 3 and 4 consistently recorded the

highest detection rates

– Significantly more detections during the night-

time hours

Sperm whale - Abundance per Zone and Season

©Aude Benhemma

Thanks for

listening!

AcknowledgementsLong-term monitoring in the Shannon Estuary was supported by PReCAST

(SEACHANGE initiative 2009 to 2011), The SIFP, Shannon Foynes Port Company,

Moneypoint, Aughinish Alumina and SAC Tarbert.

Monitoring at the Renewable Energy Test Site was facilitated by the Marine Institute and

SMARTBAY

The ObSERVE Programme is a Government-funded initiative of Ireland's Department of

Communications, Climate Action & Environment in partnership with the Department of

Arts, Heritage, Regional, Rural and Gaeltacht Affairs.