Mui Dolphin Acoustic Monitoring Craig A Radford Institute of - - PowerPoint PPT Presentation

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Dec 02, 2023 37 likes •201 views

Mui Dolphin Acoustic Monitoring Craig A Radford Institute of Marine Science University of Auckland Background Hectors dolphins venture further offshore than previously thought Current protection measures use range of offshore

SLIDE 1

Māui Dolphin Acoustic Monitoring

Craig A Radford Institute of Marine Science University of Auckland

SLIDE 2

Background

Hector’s dolphins venture further offshore than

previously thought

Current protection measures use range of offshore

limits depending on the activity being controlled

Uncertainty surrounding the risk outside this area

because the distribution of Māui’s is not well-known

SLIDE 3

Key Question

How far do Māui’s venture offshore?

SLIDE 4

Deployment Site

C-POD’s and ST’s
Click Detecting ST at M2
Deployed 28/ 06/ 2018
Retrieved M2-8 15/ 11/ 2018
Lost M1 & M9
M8 malfunctioned
Additional data from

Hamilton’s Gap, New Plymouth & Whanganui

Hupman & Goetz 2017

SLIDE 5

Processing & Assumptions

Using C-POD KERNO classifier – detects click trains
Narrow Band High Frequency (NBHF)
Verify by manually scrolling through the detections
That all NBHF detections are due to Māui’s

SLIDE 6

Summary of NBHF Detections

CPOD/ Location July 2 0 1 7 August 2 0 1 7 Septem ber 2 0 1 7 October 2 0 1 7 Novem ber 2 0 1 7 M1

64 17 21 66 26 M3 6 6 22 5 M4 2 2 M5 M6 M7

SLIDE 7

Temporal Distribution of Detections

SLIDE 8

Site: M2

SLIDE 9

Site: M3

SLIDE 10

Site: M4

SLIDE 11

Hamilton’s Gap

SLIDE 12

Distribution Based on Acoustic Detections

Decreasing detection rates

SLIDE 13

Limitations

Assumption that all NBHF sounds are Māui’s
Off-axis C-POD data potentially could be unreliable
Background noise effects detection rates

SLIDE 14

ST Comparisons

July 2017 Number of Clicks 200 400 600 800 1000 1200 Instensity (dB re 1uPa) 20 40 60 80 100 120 140 July 2017 Number of Clicks 100 200 300 400 500 Intensity (dB re 1uPa) 20 40 60 80 100 120 140

Sound Trap Click Detections C-POD Click Detections

SLIDE 15

ST Comparisons

Difficult to make direct comparisons because of the

different outputs

Background noise affects the detections
Ocean Instruments developing a click train detector and

software to analyse the data in

Benefit of the ST over the C-POD is that you can get

sound data at the same time

SLIDE 16

Acknowledgements

Whitney Nelson – summer student who did the analysis
NIWA deploying and retrieving C-POD’s and ST’s