6               Dolphin-related Monitoring

Monitoring Requirements

 

6.1         According to Section 10 of the EM&A Manual, four kinds of ecological monitoring works are required during the construction phase, namely dolphin monitoring, construction-phase underwater noise monitoring, dolphin behavior monitoring and land-based dolphin behavior and movement monitoring.  The 30 days of construction-phase underwater noise monitoring, dolphin behavior monitoring and land-based dolphin behavior and movement monitoring were completed in July 2013.

 

6.2         The monitoring work shall be undertaken by suitably qualified specialist(s), (i.e. dolphin specialist and bio-acoustician), who shall have sufficient (at least 5-10 years) relevant post-graduate experience and publication in the respective aspects. They should be approved by Agriculture, Fisheries and Conservation Department (AFCD) and Environmental Protection Department (EPD).

 

Dolphin Monitoring (Line-transect Vessel Survey)

Monitoring Requirements

6.3         According to EM&A Manual Section 10.3.2, a dolphin monitoring programme should be set up to verify the predictions of impacts and to ensure that there are no unforeseen impacts on the dolphin population during construction phase.

 

6.4         Following the requirement in the EM&A Manual Section 10.4.1, the dolphin monitoring should adopt line-transect vessel survey method, and cover the following line-transect survey areas as in AFCD annual marine mammal monitoring programme.

Monitoring Location

6.5         For this contract, dolphin monitoring will be carried out in the West Lantau (WL) along the line transect as depicted in Figure 1 of Appendix I. The co-ordinates of all transect lines are shown in Table 6.1.

 

Table 6.1  Co-ordinates of transect lines in WL survey area

Line No.

Easting

Northing

Line No.

Easting

Northing

1

Start Point

803750

818500

7

Start Point

800200

810450

1

End Point

803750

815500

7

End Point

801400

810450

2

Start Point

803750

815500

8

Start Point

801300

809450

2

End Point

802940

815500

8

End Point

799750

809450

3

Start Point

802550

814500

9

Start Point

799400

808450

3

End Point

803700

814500

9

End Point

801430

808450

4

Start Point

803120

813600

10

Start Point

801500

807450

4

End Point

801640

813600

10

End Point

799600

807450

5

Start Point

801100

812450

11

Start Point

800300

806500

5

End Point

802900

812450

11

End Point

801750

806500

6

Start Point

802400

811500

12

Start Point

801760

805450

6

End Point

800660

811500

12

End Point

800700

805450

Monitoring Frequency

6.6         Dolphin transect survey was carried out at least twice a month (i.e. complete all the transect lines of West Lantau survey area twice per month) throughout the construction period.

Monitoring Day

6.7         Dolphin monitoring was carried out on 4th and 11th November 2016. The dolphin monitoring schedule for the reporting period is shown in Appendix D. 

Monitoring Results

6.8         From these surveys, a total of 68.20 km of survey effort was collected, with 96.1% of the total survey effort being conducted under favorable weather conditions (i.e. Beaufort Sea State 3 or below with good visibility) Out of the 68.20 km of survey effort, the total survey effort conducted on primary lines (the horizontal lines perpendicular to the coastlines) was 44.54 km.

 

6.9         7 groups of 28 Chinese White Dolphins were sighted from primary lines. None of the dolphin groups was associated with an operating fishing vessel. Distribution of the 8 dolphin sightings made during November’s surveys is shown in Figure 4 of Appendix I. The sighting were evenly distributed across the survey area, ranging from just to the south of HKLR alignment in the north, to Fan Lau in the south, with no particular concentration (Figure 4 of Appendix I). It appeared that dolphin groups occurred more often in offshore waters than inshore waters within the survey area in this monitoring month (Figure 4 of Appendix I).

 

6.10     Dolphin encounter rates deduced from the survey effort and on-effort sighting data made under favourable conditions (Beaufort 3 or below) are shown in Table 6.2.

 

Table 6.2                Dolphin encounter rates (sightings per 100 km of survey effort) in November’s surveys

 

Encounter rate (STG)     (no. of on-effort dolphin sightings per 100 km of survey effort)

Encounter rate (ANI)            (no. of dolphins from all on-effort sightings per 100 km of survey effort)

Primary Lines Only

Primary Lines Only

WL

Set 1: November 4th

4.5

4.5

Set 2: November 11th

28.6

128.8

 

6.11     The average group size of Chinese White Dolphins was 3.9 individuals per group during November’s surveys, which was similar to the averages in previous months of monitoring surveys.

 

6.12     Half of the eight dolphin groups were small in size with 1-3 animals, while the other half were moderate in size with 4-8 animals per group (Appendix II).

 

6.13     During this month of dolphin monitoring, marine construction activities have continued under this contract.  However, no adverse impact on Chinese white dolphins was noticeable from general observations.

 

6.14     Evaluation of impacts on dolphins due to construction work will be conducted in the quarterly EM&A report.

 

6.15     Detailed monitoring methodology and results can be found in Appendix I.

 

Additional Land-based Dolphin Behaviour and Movement Monitoring

 

6.16     A total of 64 days of additional monitoring according to the Proposal for Land-based Dolphin Behaviour and Movement Monitoring had been completed in August 2016.

 

6.17     Detailed monitoring methodology and results will be provided in a separate report.