4.                    ECOLOGY MONITORING

4.1                    Monitoring Requirements

4.1.1                                 All marine-based construction activities for the HKBCF project were completed in January 2019. No marine-based construction activities will be undertaken under this Contract. However, the ET of this Contract or another ET of the HZMB is required to conduct post-construction dolphin monitoring in accordance with Section 10.7 of the updated EM&A Manual.

4.1.2                                 Currently, the role of dolphin monitoring and data collection are still under Contract No. HY/2012/08 “Tuen Mun-Chek Lap Kok Link – Northern Connection Sub-sea Tunnel Section”. To avoid redundancy in the monitoring effort, the findings of Contract No. HY/2012/08 were used for this reporting month. The relevant sections of dolphin monitoring report of Contract No. HY/2012/08 for this reporting month is extracted and given in Appendix O.

4.1.3                                 The CV of the proposed dolphin specialist for this Contract has been submitted to IEC for review prior to submission to AFCD for approval.

4.1.4                                 According to the Proposal on Post-construction Dolphin Monitoring (PCDM) prepared by Contract No. HY/2013/04 which has been verified and approved by ENPO and EPD respectively as shown in Appendix P, the tentative completion date of the PCDM is in February 2021. Therefore, the reporting of Chinese White Dolphins (CWD) monitoring works under this Contract was suspended on 1 March 2021.

4.2                   Monitoring Locations and Methodology

4.2.1                                 In accordance with the requirements of the updated EM&A manual, the dolphin monitoring programme have adopted the standard line-transect method (Buckland et al. 2001) to survey the pre-set and fixed transect lines defined by AFCD in the Northeast Lantau (NEL) and Northwest Lantau (NWL) survey areas.

4.2.2                                 The coordinates of the transect lines are shown in Table 1 of Appendix O. The map of the transect lines provided by AFCD is presented in Figure 4.

4.2.3                                 The details of the line-transect method (Buckland et al. 2001) adopted in the survey and the photo-identification work when CWD are sighted are presented in Section 2 of Appendix O.

4.3                   Monitoring Results

4.3.1                                 Vessel-based Line-Transect Survey

4.3.1.1                        Two sets of vessel-based line transect surveys were conducted in NWL and NEL survey areas on 2, 8, 18 and 23 February 2021. The survey routes are presented in Figures 2 to 5 of Appendix O.

4.3.1.2                        During the 2 and 18 February 2021 surveys, several boats and barges involved in construction works near the southern end of Transect Line No. 8 were observed. Due to safety considerations, the survey vessel did not traverse these areas. Therefore, only a partial survey of Transect Line No. 8 was conducted as shown in Figures 2 & 4 of Appendix O.

4.3.1.3                        A total of 261.83 km of survey effort was collected, with 100% of the total survey effort being conducted under favourable weather conditions (i.e. Beaufort Sea State 3 or below with good visibility) (Annex I of Appendix O).

4.3.1.4                        A total of 97.70 km and 164.13 km of survey effort were collected from NEL and NWL survey areas, respectively while the total survey effort conducted on primary and secondary lines were 194.39 km and 67.44 km, respectively (Annex I of Appendix O).

4.3.1.5                        During the reporting period, a total of five groups of 13 CWD were sighted in NWL and no CWD sighted in NEL. Four of the five dolphin sightings were made on the primary lines during on-effort search, and none of them was not associated with any operating fishing vessel (Annex II of Appendix O).

4.3.1.6                        Two larger groups of CWDs were sighted at the southwestern end of NWL survey or just to the north of the HKLR alignment, while the other three dolphin sightings (all being singletons) were scattered to the north east of Lung Kwu Chau as well as at the northwestern corner of the 3RS work site. Notably, the five dolphin groups were all sighted very far away from the TMCLKL alignment and the HKBCF work site (Figure 6 of Appendix O).

4.3.1.7                        Encounter rates of Chinese White Dolphin deduced from the survey effort and on-effort dolphin sighting data made under favourable conditions (Beaufort 3 or below) in February 2021 are presented in Table 4.1 & Table 4.2.

4.3.2                                 Photo-identification Work

4.3.2.1                        Nine known CWD were sighted nine times in total (Annexes III and IV of Appendix O). All of them were re-sighted only once during this month of monitoring surveys.

4.3.2.2                        Notably, two mothers (i.e. WL98 and WL145) were both sighted with their young calves in this monitoring month.