hvalatal „acoustic techniques to study marine mammals“ rannsókna- og fræðasetur háskóla...

HVALATAL „ACOUSTIC TECHNIQUES TO STUDY MARINE MAMMALS“

Rannsókna- og fræðasetur Háskóla Íslands á Norðausturlandi, Húsavík Húsavík Research CenterMarianne Helene Rasmussen

Markmið - Aim

Rannsóknir á sjávarspendýrum Research on marine mammals

The past

Research on white-beaked dolphins Humpback whales singing in Icelandic

waters?

White-beaked dolphins

Echolocation

Automatic gain control?

Source levels of clicks

150

160

170

180

190

200

210

220

230

240

250

1 10 100Range (m)

So

urc

e l

eve

l (d

B r

e.

1P

a (p

-p))

two way transmission loss (40logR)

y = 19log(x) + 192R2 = 0.68

Rasmussen et al., 2002

A click sequence

Rasmussen and Miller, 2002

Click

inte

rvals (m

s)

Time (ms)

Start frequency

End frequency

duration1 2

seconds

40

kHz

20

5

Rasmussen and Miller, 2002

Whistles

Directionality of the signals?

Narrow beam for echolocation Broad beam for communication

Rasmussen et al., 2004

Rasmussen et al, 2006

High frequency on-axis click

F0= 94 kHz

SL=176 dB

F0= 56 kHz, SL=159 dB

F0= 87 kHz, SL=173dB

F0= 63 kHz, SL=163 dB

-60 dB

-72 dB

Audiogram of a dolphin?

Audiogram of a dolphin?

We netted two dolphins in > 340 hrs on the water

Audiogram of a dolphin?

Audiogram of a dolphin?

40

60

80

100

120

10 100 1000

40

60

80

100

120

10 100 1000Frequency (kHz)

SP

L (

dB

re:

1 µ

Pa)

40

60

80

100

120

10 100 1000

40

60

80

100

120

10 100 1000Frequency (kHz)

SP

L (

dB

re:

1 µ

Pa)

Audiogram of a dolphin?

Nachtigall et al., 2008

Acoustic tagging and foraging

08/03/-2006 1:00:00 08/03/-2006 3:00:00 08/03/-2006 5:00:00 08/03/-2006 7:00:00

Fo

rag

ing

de

pth

(m

)

0

10

20

30

40

19 fouraging events

Migration of a white-beaked dolphin

8 August 2006 to 24 February 2007 (201 days)

Total distance traveled=5280 km(1090 km in August)Average speed=4 km/hrSpent 44% of time in Faxaflói BayFaxaflói

Breiðafjörður

100 m depth contour

Vestmannaeyjar

Aug

Sept

Dec

Oct

Nov, Feb

Aug, Oct to Feb

Jan

Release of dolphin

Humpback whale song

The goal was to compare humpback whale song from the Northeast Atlantic population. Do they sing the same song in Icelandic waters as by the Cap Verde islands?

theme 1

phrase 1units

theme 2

phrase 2

song

song

phrase 1

Humpback whale song

The future

Deploying Ecological Acoustic Recorders (EAR’s) in Skjálfandi Bay in Cooperation with Dr. Marc Lammers, University of Hawaii to study the annual distribution of Cetaceans in the Bay

EAR’s

Variable bandwidth up to 30 kHz

The future

Recordings of Blue whales Recordings of killer whales

Thank you for your attention