¨ description of the physical environmental background;
¨ description and quantification as far as possible of the existing fisheries activities;
¨ identification of parameters and area that are important to fisheries;
¨ identification and quantification as far as possible of any direct or indirect and on-site or off-site impacts to fisheries; and
¨ proposals for any practicable alternatives or mitigation measures to prevent or minimise adverse impacts on fisheries.
¨ the Marine Fish Culture Ordinance (Cap. 353) 1983 which regulates and protects marine fish culture zones (FCZ) that are designated under the ordinance. It is a criminal offence to discharge polluting substances into an FCZ;
¨ the Fisheries Protection Ordinance (Cap. 171) 1987 which regulates fishing activities for the conservation of fisheries resources and other marine life; and
¨ reference was also made to Annexes 9 and 17 of the Technical Memorandum EIAO (Cap. 499) 1997 in order to determine the potential impacts to fisheries resources in the Study Area. The criteria include the following:
- to prevent any significant impacts to sensitive fisheries areas particularly the nursery and spawning grounds of commercially important species of fish, crustaceans, molluscs and other marine life;
- to prevent significant loss or interference with the use of fishing grounds and FCZ’s; and
- to prevent significant impacts to local fishery resources and fishing activities.
¨ New Airport Master Plan (Greiner-Maunsell, 1991);
¨ Feasibility Study & Environmental Impact Assessment for Aviation Fuel Pipeline (Montgomery Watson, 1996);
¨ Feasibility Study for Additional Cross-border Links Stage 2 (Mouchel, 1998);
¨ EIA for the Proposed Sand Extraction from The Brothers’ Marine Borrow Area (Hyder Consulting, 1998);
¨
EIA Study for Disposal of
Contaminated Mud in the
¨ EA Study for Backfilling of Marine Borrow Pits at North of the Brothers (Mouchel, 2002);
¨
Route
10
¨
¨ Port Survey 96/97 and Port Survey 2001/2002, Fisheries Management Division, AFCD (AFCD, 1998, 2003).
12.3.2.1 Recent information on the capture fisheries is summarised in the Port Survey 96/97 (AFCD, 1998) and in the Report on Fisheries Resources and Fishing Operations in Hong Kong Waters (ERM, 1998). The PAFF pipeline and berthing jetty passes interfaces with two fishing areas, namely, the Tap Shek Kok and Lung Kwu Sha Chau fishing areas, as identified in the Port Survey 96/97 Report. The proposed 4.8km twin subsea pipeline is located approximately equally in each fishing area. The two fishing areas within the PAFF study area are significantly different in size and comprised the following:
¨ Area 33 - Lung Kwu Sha Chau comprising an area of 3,616.46 ha; and
¨ Area 43 – Tap Shek Kok comprising an area of 822.57 ha.
12.3.2.2 The total value and ranking of the fisheries resources in each of
these fishing areas that lie within the study area are presented below in Table
12.1. The Lung Kwu Sha Chau fishing area is of reasonably high value and ranks quite highly in terms of adult fished
biomass and overall value per hectare on a
Table 12.1 Fisheries Production in Each Fishing Area (all fishing vessels)
Fishing
Area (ha) |
Total Production |
Production
(ha-1) |
Rank
Production (ha-1) |
||||||
Adult
Fish (kg) |
Fry
(tails) |
Value
(HK$) |
Adult
Fish (kg) |
Fry
(tails) |
Value
(HK$) |
Adult
Fish |
Fry |
Value |
|
Lung Kwu Sha
Chau 3,616.46 |
651,700.0 |
- |
11,828,364.8 |
180.2 |
- |
3,270.71 |
53 |
- |
82 |
Tap Shek Kok 822.57 |
66,218.3 |
- |
1,958,466.6 |
80.5 |
- |
2,380.9 |
105 |
- |
98 |
Note: Based on the 189 fishing areas in
12.3.2.3 The two fishing areas are subunits of a wider sector area that occupies the sea around North of Lantau. It is conceivable that impacts from the dredging operations could reach these wider regional areas and so a summary of the fishery for the region is included here. Thus, in terms of production by hectare the region ranks quite highly (4th out of 12 sectors) and is relatively valuable, however, the fry fishery is not nearly so productive (ranked 9 out of 12).
12.3.2.4 Apart from a category labelled as mixed fish, the AFCD Port Survey 96/97 identifies the top four species caught in the region as scad (Caranx kalla), gizzard shad (Clupanodon punctatus), sardine (Sardinella jussieu) and croaker (Argyrosomus spp.). These fish catches reflect the operations in the area, which are dominated by larger fishing vessels and notably hang trawlers fishing pelagic species. On a smaller scale, mixed fish species were also the most abundant fisheries resource in each of the fishing areas, followed by shrimp scad, gizzard shad and sardine (Lung Kwu Sha Chau) and gizzard shad, lionhead and croaker (Tap Shek Kok). A summary of the top ten adult fisheries resources caught in each fishing area is presented below in Table 12.2.
Table 12.2 Most Abundant Adult Fisheries Resources from the Study Area (by Biomass)
Rank by Biomass |
Fishing Area |
|
Lung Kwu Sha Chau |
Tap Shek Kok |
|
1 |
Mixed Species |
Mixed Species |
2 |
Caranx kalla (shrimp scad) |
ClupanodonPunctatus(gizzard shad) |
3 |
Clupanodon Punctatus (gizzard shad) |
Collichthys lucida (lionhead) |
4 |
Sardinella jussieu (sardine) |
Argyrosomus spp. (croaker) |
5 |
Trichiurus haumela (hairtail) |
Mugil affinis (mullet) |
6 |
Mugil affinis (mullet) |
Caranx kalla (shrimp scad) |
7 |
Argyrosomus spp. (croaker) |
Acetes spp. (silver
shrimp) |
8 |
Collichthys lucida (lionhead) |
Platycephalus indicus (flathead) |
9 |
Decapterus lajang (scad) |
Ilisha elongata(white herring) |
10 |
Stolephorus spp. (anchovy) |
Eleutheronema
tetradactylus (threadfin) |
Note: Mixed species is mixed fish considered of lower commercial value. Source: Based on Port Survey 96/87.
12.3.2.5 The more recent Port Survey 2001/2002 (AFCD, 2003) present the survey results in density grid, as shown in Figure 12.1, instead of fishing areas. With respect to Figure 12.1, essentially only cells B5 (Sha Chau) and C4 (Tak Shek Kok) would be affected by the proposed dredging works. The patterns revealed in Port Survey 2001/2002 were essentially the same as Port Survey 96/97 and in generally the Sha Chau area was more productive and the products were also more valuable compared to Tap Shek Kok. Although there were more small boats (<15m) operating in the two areas than the large vessel (>15m), the production of the small boat was low and ranked the second lowest across Hong Kong waters. Thus, impacts from the dredging operations to small boat operators are likely to be localised around the study area and are not likely to range wider. As the area is not the major operating area for the large trawling vessels (>15m), impacts to them would also be limited. The results of the Port Survey 2001/2002 are summarised in Table 12.3 below:
Table 12.3 Catch Statistics of Sha Chau and Tap Shek Kok, Port Survey 2001/2002
Cell1(Area) |
B5 (Sha Chau) |
Rank2 |
C4 (Tap Shek
Kok) |
Rank2 |
No. of Vessels |
100-400 |
3/6 |
100-400 |
3/6 |
Small Boat <15m) |
100-400 |
3/6 |
100-400 |
3/6 |
Large Vessel (>15m) |
50-100 |
4/6 |
10-50 |
5/6 |
Total Adult Fish |
200-400 kg/ha |
3/6 |
50-100 |
5/6 |
Production |
5,000-10,000 $/kg |
2/6 |
1,000 - 2,000 $/kg |
4/6 |
By small boat (<15m) |
50-100 kg/ha |
5/6 |
0-50 kg /ha |
5/6 |
By large vessel (>15m) |
100-200 kg/ha |
3/6 |
0-50 kg/ ha |
6/6 |
Fry production |
- |
- |
- |
- |
Main Catch |
shrimp: 20-40 kg/ha |
3/6 |
shrimp: 5-10 kg/ha |
5/6 |
|
sciaenidae: 20-40 kg/ha |
3/6 |
Clupeidae: 5-10 kg/ha |
5/6 |
|
|
|
Siganidae: 5-10 kg/ha |
5/6 |
Note: 1Cell number refers to grid in Figure 12.1; 2A scale of 1-6 was used in Port Survey 2001/2002 and the 1st is the highest rank.
12.3.2.6 Trawling is conducted as part of the ongoing EM&A programme for the contaminated mud pits in locations near the study area at sites around Lung Kwu Chau, off the airport and around the mud pits. The trawling locations are presented in Figure 12.2. The most recent fisheries data covering both the dry (January-February 2005; Mouchel, 2005b) and wet (October 2005; Meinhardt, 2006b) seasons from the Northwestern waters.
12.3.2.7 The January-February 2005 dry season survey recorded a total of 177 different species. Of these faunal groups, bivalves, crabs, fish, gastropods, shrimps (including mantis shrimp) and prawns were the most abundant. The gastropods were numerically dominant and 3,163 individuals were trawled in January-February 2005. Crabs were the second most dominant species and 2,085 individuals were recorded in the dry season, although it should be noted that not all these crabs and gastropods are commercial species. Fish were also abundant and 2,638 individuals were recorded in the dry season and were the most diverse group represented by 66 different species. In terms of numerical dominance, the most common fish recorded were the croaker (Johnius macrorhynus), the gobies (Trypauchen vagina), Saddleback silver-biddy (Gerres lucidus (=limbatus)) and mullet (Valamugil formosae). The commercially important mantis shrimps (mostly Oratosquilla interrupta) and prawns (Metapenaeus spp. and Penaeus spp.) were also numerically abundant components of the trawls. The commercially important species (cephalopds, crabs, mantis shrimp, shrimp and fish) trawled from locations around Sha Chau during the January-February 2005 dry season are presented below in Table 12.4.
Table 12.4 Species Composition and Abundance of
Individuals (Total Counts) from Trawling in Dry Season (January-February 2005)
Group |
Species |
FS1 |
FS2 |
FS3 |
FS4 |
FS5 |
FS6 |
Total |
Cephalopod |
Loligo sp. |
|
2 |
7 |
3 |
4 |
5 |
21 |
|
Octopus sp. |
|
|
3 |
|
1 |
2 |
6 |
|
Sepiella
japonica |
|
|
|
|
|
1 |
1 |
|
Sepiella sp. |
|
|
1 |
2 |
|
1 |
4 |
Cephalopod
Total |
|
|
2 |
11 |
5 |
5 |
9 |
32 |
Crab |
Charybdis acuta |
13 |
|
3 |
|
11 |
12 |
39 |
|
Charybdis
affinis |
1 |
4 |
3 |
|
19 |
12 |
39 |
|
Charybdis
anisodon |
|
|
|
|
1 |
|
1 |
|
Charybdis
cruciata |
5 |
2 |
7 |
1 |
16 |
14 |
45 |
|
Charybdis
hellerii |
|
3 |
|
|
4 |
|
7 |
|
Charybdis
japonica |
111 |
151 |
85 |
50 |
510 |
222 |
1,129 |
|
Charybdis
truncata |
|
7 |
7 |
1 |
9 |
21 |
45 |
|
Charybdis
variegata |
5 |
9 |
|
3 |
2 |
12 |
31 |
|
Clibanarius sp. |
1 |
8 |
24 |
27 |
34 |
39 |
133 |
|
Diogenes sp. |
|
11 |
|
3 |
41 |
|
55 |
|
Doclea ovis |
|
2 |
|
|
|
|
2 |
|
Dorippe polita |
|
1 |
|
|
|
|
1 |
|
Eriochier sp. |
1 |
|
|
|
|
|
1 |
|
Ethusa indica |
4 |
1 |
14 |
19 |
6 |
10 |
54 |
|
Eucrate costata |
14 |
28 |
3 |
2 |
30 |
5 |
82 |
|
Eucrate crenata |
3 |
6 |
|
2 |
7 |
1 |
19 |
|
Galene
bispinosa |
7 |
|
4 |
3 |
1 |
|
15 |
|
Goniohellenus
vadorum |
|
11 |
40 |
35 |
|
3 |
89 |
|
Leucosia
vittata |
|
6 |
|
|
3 |
21 |
30 |
|
Macrophthalmus
japonicus |
|
|
|
1 |
|
1 |
2 |
|
Macrophthalmus
latreillei |
|
1 |
|
|
|
|
1 |
|
Platylambrus
validus |
|
4 |
9 |
9 |
4 |
50 |
76 |
|
Portunus
hastatoides |
|
2 |
5 |
3 |
9 |
4 |
23 |
|
Portunus
pelagicus |
|
|
|
|
9 |
14 |
23 |
|
Procelain crab |
|
2 |
1 |
2 |
28 |
91 |
124 |
|
Scalopidia
spinosipes |
|
|
|
|
|
1 |
1 |
|
Thalamita sima |
|
|
2 |
|
2 |
2 |
6 |
|
Typhlocarcinops
denticarpes |
|
|
1 |
|
|
|
1 |
|
Typhlocarcinus
nudus |
5 |
4 |
|
|
|
|
9 |
|
Typhlocarcinus
villosus |
1 |
|
|
1 |
|
|
2 |
Crab Total |
|
171 |
263 |
208 |
162 |
746 |
535 |
2,085 |
Fish |
Acentrogobius
caninus |
5 |
3 |
14 |
11 |
83 |
25 |
141 |
|
Ambassis
gymnocephalus |
23 |
|
|
|
|
|
23 |
|
Amblychaeturichthys
hexanema |
6 |
10 |
1 |
2 |
3 |
|
22 |
|
Apogon kiensis |
|
|
|
|
2 |
|
2 |
|
Apogon lineatus |
|
|
|
|
|
1 |
1 |
|
Apogon
pseudotaeniatus |
|
1 |
|
|
|
|
1 |
|
Arnoglossus
tenuis |
|
|
1 |
1 |
9 |
5 |
16 |
|
Chaeturichthys
stigmatias |
15 |
25 |
4 |
5 |
1 |
|
50 |
|
Chrysochir
aureus |
|
|
1 |
|
|
|
1 |
|
Coilia grayii |
9 |
27 |
2 |
|
|
1 |
39 |
|
Collichthys
lucidus |
2 |
8 |
2 |
|
6 |
1 |
19 |
|
Cryptocentrus
filifer |
|
|
|
|
20 |
1 |
21 |
|
Cynoglossus
arel |
20 |
15 |
6 |
5 |
47 |
26 |
119 |
|
Cynoglossus
gracilis |
|
|
|
|
|
1 |
1 |
|
Cynoglossus
itinus |
|
|
|
|
|
1 |
1 |
|
Cynoglossus
joyneri |
21 |
18 |
13 |
7 |
10 |
1 |
70 |
|
Cynoglossus
puncticeps |
|
2 |
|
|
2 |
2 |
6 |
|
Cynoglossus
semilaevis |
10 |
6 |
1 |
|
8 |
6 |
31 |
|
Dasyatis
bennettii |
|
|
|
|
|
4 |
4 |
|
Dasyatis zugei |
|
|
1 |
|
|
|
1 |
|
Dendrophysa
russelii |
17 |
26 |
15 |
29 |
12 |
19 |
118 |
|
Epinephelus
bruneus |
|
|
|
|
1 |
|
1 |
|
Gerres lucidus |
|
|
7 |
10 |
20 |
145 |
182 |
|
Gymnothorax
reevesii |
|
|
|
|
1 |
|
1 |
|
Ilisha elongata |
2 |
5 |
|
|
|
|
7 |
|
Inegocia
japonica |
|
|
|
|
4 |
3 |
7 |
|
Inimicus
japonicus |
|
|
|
|
1 |
2 |
3 |
|
Johnius
belangerii |
1 |
11 |
1 |
|
2 |
15 |
30 |
|
Johnius
macrorhynus |
12 |
15 |
134 |
59 |
86 |
222 |
528 |
|
Larimichthys
polyactis |
|
|
2 |
|
|
|
2 |
|
Lateolabrax
japonicus |
|
1 |
|
|
|
1 |
2 |
|
Leiognathus
brevirostris |
1 |
1 |
1 |
1 |
8 |
38 |
50 |
|
Liza affinis |
|
|
|
1 |
|
|
1 |
|
Muraenesox
cinereus |
|
1 |
|
1 |
1 |
|
3 |
|
Nemipterus
japonicus |
|
|
1 |
1 |
1 |
|
3 |
|
Ophichthus
celebicus |
|
|
|
|
1 |
|
1 |
|
Otolithes ruber |
|
|
4 |
3 |
1 |
2 |
10 |
|
Oxyurichthys
tentacularis |
4 |
|
8 |
13 |
7 |
3 |
35 |
|
Parachaeturichthys
polynema |
8 |
50 |
4 |
3 |
13 |
2 |
80 |
|
Pennahia
argentata |
|
|
1 |
2 |
3 |
2 |
8 |
|
Pisodonophis
cancrivorus |
|
|
|
|
1 |
|
1 |
|
Platycephalus
indicus |
4 |
4 |
16 |
14 |
23 |
24 |
85 |
|
Plotosus lineatus |
|
|
1 |
|
|
1 |
2 |
|
Polydactylus
sextarius |
|
1 |
5 |
15 |
5 |
5 |
31 |
|
Prionobutis
koilomatodon |
|
|
|
|
|
1 |
1 |
|
Pseudorhombus
arsius |
|
|
1 |
|
|
1 |
2 |
|
Saurida
elongata |
|
|
|
2 |
|
|
2 |
|
Scatophagus
argus |
|
|
|
|
|
4 |
4 |
|
Sebastiscus
albofasciatus |
|
|
|
|
|
1 |
1 |
|
Sebastiscus
marmoratus |
|
|
|
|
|
1 |
1 |
|
Siganus
canaliculatus |
|
1 |
2 |
|
|
5 |
8 |
|
Sillago sihama |
1 |
|
|
1 |
9 |
27 |
38 |
|
Solea ovata |
|
3 |
3 |
2 |
43 |
68 |
119 |
|
Syngnathus
schlegeli |
3 |
3 |
5 |
6 |
3 |
|
20 |
|
Takifugu
niphobles |
|
|
|
1 |
|
|
1 |
|
Takifugu
oblongus |
|
|
|
|
|
3 |
3 |
|
Takifugu
poecilonotus |
|
|
|
|
|
1 |
1 |
|
Takifugu
xanthopterus |
|
|
|
|
|
1 |
1 |
|
Thryssa
chefuensis |
|
|
|
|
|
1 |
1 |
|
Thryssa
hamiltonii |
|
4 |
3 |
|
10 |
2 |
19 |
|
Trachycephalus
uranoscopa |
1 |
1 |
3 |
2 |
18 |
43 |
68 |
|
Trichiurus
lepturus |
1 |
|
|
|
|
1 |
2 |
|
Trypauchen
vagina |
155 |
122 |
10 |
20 |
66 |
54 |
427 |
|
Uroconger
lepturus |
|
|
1 |
2 |
|
|
3 |
|
Valamugil formosae |
|
|
50 |
77 |
5 |
20 |
152 |
|
Zebrias zebra |
3 |
1 |
|
|
|
|
4 |
Fish Total |
|
324 |
365 |
324 |
296 |
536 |
793 |
2,638 |
Mantis shrimp |
Clorida
decorator |
1 |
|
|
1 |
|
1 |
3 |
|
Dictyosquilla
foveolata |
6 |
2 |
|
1 |
|
|
9 |
|
Harpiosquilla
harpax |
5 |
3 |
24 |
17 |
7 |
8 |
64 |
|
Oratosquilla
interrupta |
90 |
46 |
31 |
41 |
29 |
11 |
248 |
|
Oratosquilla
oratoria |
6 |
7 |
15 |
11 |
43 |
24 |
106 |
Mantis shrimp
Total |
|
108 |
58 |
70 |
71 |
79 |
44 |
430 |
Prawn or Shrimp |
|
1 |
5 |
|
3 |
17 |
1 |
27 |
|
|
26 |
43 |
5 |
11 |
7 |
|
92 |
|
|
|
5 |
|
1 |
|
|
6 |
|
Exopalaemon
carinicauda |
25 |
|
|
|
|
|
25 |
|
Metapenaeopsis
barbata |
|
1 |
1 |
|
9 |
|
11 |
|
Metapenaeus
affinis |
48 |
6 |
|
2 |
2 |
36 |
94 |
|
Metapenaeus
burkenroadi |
1 |
2 |
4 |
3 |
|
1 |
11 |
|
Metapenaeus
ensis |
9 |
1 |
|
3 |
27 |
5 |
45 |
|
Metapenaeus
joyneri |
18 |
20 |
7 |
33 |
7 |
7 |
92 |
|
Parapenaeopsis
hardwickii |
177 |
36 |
1 |
6 |
18 |
2 |
240 |
|
Parapenaeopsis
hungerfordi |
287 |
250 |
12 |
16 |
32 |
7 |
604 |
|
Penaeus
orientalis |
3 |
3 |
7 |
8 |
29 |
143 |
193 |
|
Penaeus
penicillatus |
|
|
|
3 |
3 |
|
6 |
|
Scyllarus
martensii |
|
|
|
1 |
|
3 |
4 |
|
Solenocera
crassicornis |
157 |
70 |
3 |
20 |
2 |
1 |
253 |
|
Trachypenaeus
curvirostris |
1 |
2 |
|
1 |
1 |
|
5 |
|
Trachypenaeus
fulvus |
12 |
10 |
1 |
|
|
2 |
25 |
Prawn or Shrimp
Total |
|
765 |
454 |
41 |
111 |
154 |
208 |
1,733 |
Note: Not all crab species are commercially important although they are important components of the marine system and are included for completeness. Source: Mouchel (2005b).
12.3.2.8 The October 2005 late wet season survey recorded a total of 165 different species. Of these faunal groups, bivalves, crabs, fish, gastropods, shrimps (including mantis shrimp) and prawns were also the most abundant. The gastropods were numerically dominant and 26,056 individuals were trawled in October 2005. Bivalves were the second most abundant species and 20,143 individuals were recorded while crabs were the third most dominant species and 4,644 individuals were recorded in the dry season. It should be noted that not all these bivalve, crabs and gastropods are commercial species and when compared to the results of the dry season surveys, blooming of molluscs (bivalve and gastropods) were often recorded in the area (Mouchel, 2005a). Fish were also abundant and 3,671 individuals were recorded in the wet season and were the most diverse group represented by 69 different species. In terms of numerical dominance, the most common fish recorded were the mullet (Mugil cephalus), the gobies (Trypauchen vagina), the pony fish (Leiognathus brevirostris), another gobies (Oxyurichthys tentacularis) and the Striped threadfin (Polydactylus sextarius). The commercially important mantis shrimps (mostly Oratosquilla interrupta) and prawns (Metapenaeus spp. and Penaeus spp.) were also numerically abundant components of the trawls. The commercially important species (cephalopds, crabs, mantis shrimp, shrimp and fish) trawled from locations around Sha Chau during the October 2005 wet season are presented below in Table 12.5.
Table 12.5 Species Composition and Abundance of
Individuals (Total Counts) from Trawling in Wet Season (October 2005)
Group |
Species |
FS1 |
FS2 |
FS3 |
FS4 |
FS5 |
FS6 |
Total |
Cephalopod |
Loligo sp. |
|
|
|
1 |
|
2 |
3 |
|
Octopus sp. |
|
|
|
1 |
7 |
2 |
10 |
|
Sepiella sp. |
2 |
|
|
|
|
|
2 |
Cephalopod Total |
|
2 |
|
|
2 |
7 |
4 |
15 |
Crab |
Calappa philargius |
|
8 |
|
|
|
60 |
68 |
|
Calappa sp. |
|
|
|
|
|
2 |
2 |
|
Charybdis acuta |
19 |
116 |
9 |
8 |
112 |
35 |
299 |
|
Charybdis affinis |
80 |
273 |
59 |
74 |
165 |
81 |
732 |
|
Charybdis callianassa |
|
|
|
|
|
15 |
15 |
|
Charybdis cruciata |
1 |
18 |
52 |
20 |
53 |
26 |
170 |
|
Charybdis hellerii |
|
|
|
|
2 |
9 |
11 |
|
Charybdis japonica |
96 |
804 |
469 |
279 |
413 |
215 |
2,276 |
|
Charybdis truncata |
|
|
9 |
|
1 |
2 |
12 |
|
Charybdis variegata |
|
2 |
|
|
2 |
2 |
6 |
|
Clibanarius sp. |
27 |
148 |
31 |
23 |
16 |
45 |
290 |
|
Diogenes sp. |
5 |
20 |
|
2 |
13 |
2 |
42 |
|
Doclea gracilipes |
2 |
20 |
1 |
7 |
|
1 |
31 |
|
Doclea ovis |
|
6 |
|
|
|
|
6 |
|
Dorippe polita |
|
1 |
|
|
|
|
1 |
|
Ethusa indica |
2 |
|
81 |
85 |
13 |
47 |
228 |
|
Eucrate costata |
|
|
|
|
16 |
|
16 |
|
Eucrate crenata |
|
24 |
3 |
|
3 |
|
30 |
|
Galene bispinosa |
2 |
23 |
5 |
|
2 |
4 |
36 |
|
Goniohellenus vadorum |
7 |
1 |
24 |
40 |
30 |
16 |
118 |
|
Halimede sp. |
|
|
|
|
|
1 |
1 |
|
Leucosia vittata |
|
2 |
15 |
5 |
|
6 |
28 |
|
Macrophthalmus japonicus |
|
|
2 |
|
|
|
2 |
|
Platylambrus validus |
|
|
2 |
3 |
4 |
8 |
17 |
|
Porcelain crab |
|
|
3 |
|
17 |
17 |
37 |
|
Portunus hastatoides |
2 |
6 |
4 |
28 |
1 |
8 |
49 |
|
Portunus pelagicus |
1 |
4 |
|
3 |
37 |
19 |
64 |
|
Portunus sanguinolentus |
8 |
2 |
2 |
8 |
11 |
6 |
37 |
|
Portunus trituberculatus |
1 |
|
|
1 |
|
|
2 |
|
Scylla serrata |
|
|
|
|
|
1 |
1 |
|
Thalamita sima |
|
|
|
|
|
1 |
1 |
|
Typhlocarcinus nudus |
4 |
|
5 |
7 |
1 |
1 |
18 |
Crab Total |
|
257 |
1478 |
774 |
593 |
912 |
630 |
4,644 |
Fish |
Acentrogobius caninus |
11 |
7 |
20 |
26 |
49 |
11 |
124 |
|
Ambassis gymnocephalus |
|
|
2 |
|
|
|
2 |
|
Amblychaeturichthys hexanema |
7 |
|
|
1 |
|
|
8 |
|
Apogon kiensis |
5 |
24 |
5 |
7 |
40 |
18 |
99 |
|
Apogon lineatus |
|
1 |
|
|
|
1 |
2 |
|
Arnoglossus tenuis |
1 |
|
|
1 |
2 |
5 |
9 |
|
Brachyamblyopus brachysoma |
|
|
|
1 |
|
|
1 |
|
Callionymus japonicus |
|
|
2 |
|
|
|
2 |
|
Cephalopholis boenak |
|
|
1 |
|
|
|
1 |
|
Chelonodon patoca |
|
|
|
|
2 |
|
2 |
|
Chrysochir aureus |
|
|
|
|
4 |
|
4 |
|
Coilia nasus |
3 |
11 |
|
|
|
|
14 |
|
Collichthys lucidus |
4 |
31 |
1 |
|
2 |
2 |
40 |
|
Cryptocentrus filifer |
|
|
1 |
|
1 |
|
2 |
|
Cynoglossus arel |
6 |
12 |
12 |
21 |
19 |
14 |
84 |
|
Cynoglossus joyneri |
18 |
6 |
9 |
12 |
1 |
|
46 |
|
Cynoglossus puncticeps |
|
|
1 |
|
1 |
1 |
3 |
|
Cynoglossus semilaevis |
1 |
|
1 |
1 |
|
|
3 |
|
Dasyatis akajei |
|
|
|
|
|
2 |
2 |
|
Dasyatis bennettii |
|
|
1 |
|
|
|
1 |
|
Dasyatis zugei |
|
|
|
|
|
1 |
1 |
|
Dendrophysa russelii |
4 |
5 |
15 |
7 |
|
6 |
37 |
|
Drepane punctata |
|
|
|
|
|
2 |
2 |
|
Epinephelus awoara |
|
|
|
|
1 |
2 |
3 |
|
Epinephelus bruneus |
|
|
|
|
2 |
4 |
6 |
|
Gerres lucidus |
|
|
5 |
1 |
33 |
20 |
59 |
|
Harpadon microchir |
|
5 |
|
|
|
|
5 |
|
Ilisha elongata |
1 |
2 |
1 |
2 |
|
|
6 |
|
Inegocia japonica |
2 |
1 |
|
|
12 |
18 |
33 |
|
Inimicus japonicus |
|
|
|
|
1 |
1 |
2 |
|
Johnius belangerii |
8 |
6 |
|
1 |
66 |
93 |
174 |
|
Johnius macrorhynus |
8 |
17 |
11 |
17 |
103 |
28 |
184 |
|
Lagocephalus gloveri |
|
|
|
|
1 |
|
1 |
|
Leiognathus brevirostris |
11 |
1 |
47 |
154 |
55 |
16 |
284 |
|
Leiognathus nuchalis |
23 |
|
|
|
|
|
23 |
|
Liza macrolepis |
|
|
|
12 |
|
|
12 |
|
Minous monodactylus |
|
|
|
|
|
2 |
2 |
|
Mugil cephalus |
3 |
|
57 |
514 |
8 |
|
582 |
|
Muraenesox bagio |
|
|
|
|
|
1 |
1 |
|
Muraenesox cinereus |
1 |
2 |
3 |
|
4 |
1 |
11 |
|
Nemipterus japonicus |
|
|
1 |
2 |
9 |
9 |
21 |
|
Nibea albiflora |
|
|
|
|
8 |
|
8 |
|
Otolithes ruber |
|
|
|
1 |
|
|
1 |
|
Oxyurichthys tentacularis |
8 |
23 |
82 |
97 |
3 |
9 |
222 |
|
Parachaeturichthys polynema |
4 |
53 |
|
|
1 |
1 |
59 |
|
Pennahia argentata |
11 |
29 |
2 |
2 |
1 |
4 |
49 |
|
Pisodonophis boro |
|
|
|
|
1 |
1 |
2 |
|
Platycephalus indicus |
9 |
5 |
44 |
30 |
53 |
49 |
190 |
|
Polydactylus sextarius |
88 |
12 |
26 |
15 |
47 |
27 |
215 |
|
Pseudorhombus arsius |
|
|
|
|
|
1 |
1 |
|
Repomucenus richardsonii |
1 |
|
|
1 |
1 |
5 |
8 |
|
Rhynchopelates oxyrhynchus |
|
|
|
|
|
1 |
1 |
|
Saurida elongata |
1 |
|
7 |
11 |
1 |
3 |
23 |
|
Sebastiscus marmoratus |
|
|
|
|
3 |
3 |
6 |
|
Siganus canaliculatus |
1 |
|
7 |
9 |
44 |
99 |
160 |
|
Sillago sihama |
|
|
|
|
3 |
11 |
14 |
|
Solea ovata |
2 |
10 |
1 |
4 |
41 |
8 |
66 |
|
Syngnathus schlegeli |
|
|
3 |
4 |
|
|
7 |
|
Takifugu ocellatus |
5 |
|
6 |
|
1 |
10 |
22 |
|
Takifugu poecilonotus |
|
|
|
|
|
2 |
2 |
|
Terapon jarbua |
|
|
1 |
3 |
6 |
35 |
45 |
|
Terapon theraps |
|
|
|
|
21 |
|
21 |
|
Thryssa hamiltonii |
|
1 |
3 |
|
1 |
2 |
7 |
|
Thryssa sp. |
|
|
|
|
|
2 |
2 |
|
Trachycephalus uranoscopa |
33 |
1 |
2 |
1 |
23 |
27 |
87 |
|
Trypauchen vagina |
255 |
65 |
30 |
28 |
56 |
27 |
461 |
|
Upeneus japonicus |
|
|
|
1 |
|
|
1 |
|
Valamugil formosae |
3 |
|
83 |
4 |
|
|
90 |
|
Zebrias zebra |
|
1 |
|
1 |
|
1 |
3 |
Fish Total |
|
538 |
331 |
493 |
992 |
731 |
586 |
3,671 |
Mantis shrimp |
Clorida sp. |
|
|
|
|
1 |
|
1 |
|
Dictyosquilla foveolata |
|
|
5 |
|
|
|
5 |
|
Harpiosquilla harpax |
9 |
41 |
312 |
308 |
82 |
34 |
786 |
|
Miyakea nepa |
1 |
|
3 |
1 |
|
|
5 |
|
Oratosquilla interrupta |
271 |
263 |
34 |
28 |
42 |
13 |
651 |
|
Oratosquilla oratoria |
15 |
28 |
35 |
22 |
13 |
2 |
115 |
Mantis shrimp Total |
|
296 |
332 |
389 |
359 |
138 |
49 |
1,563 |
Prawn or shrimp |
|
4 |
1 |
1 |
|
5 |
1 |
12 |
|
|
5 |
3 |
|
|
|
|
8 |
|
|
|
3 |
|
|
|
|
3 |
|
Exopalaemon annandalei |
|
1 |
|
|
|
|
1 |
|
Metapenaeopsis barbata |
1 |
1 |
|
|
3 |
|
5 |
|
Metapenaeus affinis |
630 |
120 |
114 |
199 |
28 |
22 |
1,113 |
|
Metapenaeus ensis |
7 |
1 |
|
|
7 |
5 |
20 |
|
Metapenaeus joyneri |
1 |
9 |
2 |
6 |
|
3 |
21 |
|
Parapenaeopsis hardwickii |
45 |
18 |
40 |
21 |
43 |
21 |
188 |
|
Parapenaeopsis hungerfordi |
63 |
31 |
33 |
23 |
35 |
19 |
204 |
|
Penaeus monodon |
|
1 |
|
|
|
1 |
2 |
|
Penaeus orientalis |
|
1 |
17 |
12 |
16 |
22 |
68 |
|
Penaeus penicillatus |
1 |
|
1 |
2 |
|
4 |
8 |
|
Solenocera crassicornis |
113 |
86 |
64 |
81 |
3 |
5 |
352 |
Prawn or shrimp Total |
|
870 |
276 |
272 |
344 |
140 |
103 |
2,005 |
Note: Not all crab species are commercially important although they are important components of the marine system and are included for completeness. Source: Meinhardt (2006b).
12.3.3.1 The Report on Fisheries Resources and Fishing Operations in Hong Kong Waters (ERM, 1998) generally supports the information provided in the Port Survey data. The area is not identified as a primary nursery ground, however it is noted as a spawning ground for Leiognathus brevirostris, Lateolabrax japonicus and Clupanodon punctatus, which probably explains the general high catches recorded for the former species in the EM&A at East Sha Chau (e.g., Meinhardt, 2006b) and the latter species in the Port Survey 96/97 (AFCD, 1998).
12.3.4.1 The nearest culture fishery is the mariculture zone at Ma Wan located approximately 14km to the east of Tuen Mun Area 38 (this represents the nearest point between the PAFF and the FCZ). This is the only FCZ in the area which may potentially be affected by construction and operation of the PAFF. The Ma Wan FCZ consists of 108 licensed floating rafts and the main species cultured are spotted grouper (Epinephelus chlorostigma), goldlined seabream (Rhabdosargus sarba), mangrove snapper (Lutjanus argentimaculatus) and pompano (Trachinotus blochii) (Mott Connell, 1999).
Loss of
Seabed Habitat
Suspension
of Sediments
Direct Impacts
¨ physical abrasion and clogging of gills;
¨ interference with feeding apparatus;
¨ alteration of behaviour (especially in species that rely heavily on visual cues);
¨ higher susceptibility to diseases; and
¨ smothering of early-life stages particularly eggs.
Indirect Impacts
¨ suspended matter may reduce light penetration and alter primary productivity;
¨ large volumes of deposited suspended solids may alter the nature of the seabed; and
¨ suspended matter may contain organics that have an oxygen demand leading to reduced dissolved oxygen.
Suspension
of Contaminated Sediments
12.6.1.1 Annex 9 of the TMEIAO provides general criteria that can be applied in the assessment of impacts to fisheries due to developments. Construction phase impacts to fisheries associated with the PAFF project are mostly related to the potential for impacts from suspended solids and loss of habitat. Once constructed, the subsea pipeline will be backfilled with granular fill and amour rock on top. The rock armour protection would be level with the original seabed and there is no requirements for maintenance of the rock protection once place. The rest of the trench (on top of the amour rock) will be naturally filled up by sea mud as illustrated in Figure 3.3. Based upon this design, fishing gear should not be affected and there will be no implications on capture fisheries. The only potential operational phase impact to fisheries resources is due to an aviation fuel spill. The risks of such a spill have, however, been shown to be of a very low frequency and for the spills to evaporate rapidly (Section 10 and 11) and the assessment of fuel spills on fisheries are also considered insignificant, as assessed in detail in Section 11.
12.6.2.1 The PAFF study area is known to be an important spawning and nursery ground for many commercially important penaeid shrimp and fish species (AFCD, 1998; Figure 6.2 of sensitive receivers).
12.6.2.2 Fish are typically highly mobile and will generally avoid disturbed areas. On cessation of the construction phase activity, it is likely that fish will rapidly recolonise the area. Species inhabiting the areas adjacent to the dredging will be exposed to some localised elevated suspended solid levels although impacts from suspended material is likely to be minimal as it is likely that fish will either avoid the area or are adapted to local conditions (i.e., the high suspended sediment loads carried in the water column and/ or the re-suspension of soft-bottom sediments characteristic of the Northwestern waters). Furthermore, lethal impacts from suspended solids are not usually induced in fish until ambient concentrations reach 1,000 mg l-1 and it is notable that a recent study with a local fish species, the mangrove snapper (Lutjanus argentimaculatus) showed that extremely high suspended solid concentrations failed to induce toxicity. The mangrove snapper tolerated high total suspended solid loadings and the 48-h NOEC (no observable effect concentration) was 5,000 mg l-1 (AFCD, 2001).
12.6.2.3 The loss of some soft-bottom benthic habitat to dredging of the trench is only a localised temporary impact and the decrease of potential invertebrate food sources and impacts on fish and fisheries resources are considered insignificant. It is possible that detritus feeding species may be attracted through disturbance to sediments and construction may be beneficial to these species.
12.6.2.4 Dredging operations may result in some short lived plumes of sediment within the bottom layer. This bottom layer is naturally subject to large variability in suspended sediment conditions as a result of natural processes of sediment deposition and erosion. Demersal species inhabiting these waters are consequently tolerant to such variability in suspended sediment conditions. Suspended sediment concentrations within the middle and upper layers would generally not increase by more than about 5 mg/l across the study area. There would be a few transient plumes with slightly higher levels up to a maximum of about 10-15 mg/l above ambient which is within the natural variability experienced in the North Western waters. Thus pelagic species are also unlikely to be significantly impacted and are unlikely to move far from the dredging operation. Spawning activities are also unlikely to be disrupted. Fishing activities may be locally disrupted due to vessel movements and traffic restrictions, however, this will be short-term and given the high volume of marine traffic currently operating in the area, considered insignificant. The home-range of the fish involved will also generally be wider than the works area and opportunities will still exist to catch the fish elsewhere in the two fishing areas. The mariculture zone at Ma Wan is sufficiently distant from the works (>14km) that there will be no increase in suspended sediment concentrations as a result of the project. Construction-phase dredging for the trench required to accommodate the pipeline is not, therefore, likely to be a factor influencing operations at the FCZ.
12.6.2.5 As the dredging work is highly localised and will be conducted to minimise sediment resuspension (Section 6.4), impacts due to suspended solids on fisheries resources are considered insignificant and acceptable. The mitigation measures described in Section 6.7 to protect water quality sensitive receivers from elevated suspended solid concentrations should prove adequate to prevent significant impacts of suspension of the seabed sediments to fisheries resources in the study area.
12.6.2.6 In summary, the PAFF construction will result in minimal loss of the seabed as the pipeline is located in a trench. The subsea pipeline will be backfilled with granular fill and rock armour placed on top. The rest of the trench above the rock armour will be naturally filled up by marine sediments as shown in Figure 3.3 and will not affect fishing gear. As such, the structure will have minimal impact to the benthic fish prey items inhabiting sediments and will also not interfere with fishing activities.
12.6.2.7 An evaluation of the PAFF project using criteria detailed in Annex 9 of the TMEIAO is provided below in Table 12.6.
Criteria |
Predicted
Impacts |
Impact
Evaluation/ Mitigation |
Nature of impact |
Dredging of a
submarine trench for the PAFF Pipeline; and
Temporary Seabed
Loss and Potential Food Resources |
Impacts are
temporary (recolonisation of seabed is rapid as discussed in Section 7) and
temporary loss of seabed insignificant as the seabed present is homogeneous
throughout the study area. Provided that the good dredging practices
recommended in Section 6.7 are adhered to, water quality impacts and hence
impacts to fisheries are insignificant.
No other mitigation measures are required. |
Size of affected
area |
Pipeline is
4.8km and about 12.5ha of the fishing ground will be temporarily affected.
This, however, represents a very small proportion (less than 0.3%) of the
total fisheries habitat and fishing grounds in |
The area of
direct impact is small and will only be temporarily affected The suspension
of sediments during the construction phase (dredging required for laying of
the pipeline in the trench) is predicted to be highly localised and elevated
suspended solids are not predicted outside of a highly localised works area. |
Loss of fisheries
resources/ production |
The pipeline and
associated works is located in two fishing areas. Lung Kwu Sha Chau is of reasonably high value and ranks quite highly in terms of adult fished
biomass and overall value per hectare on a |
The works will
cause temporary loss of a very small percentage (<0.3%) of the fishing ground in the area. In the
worse case where a short-lived sediment plume extended 200 m from either size
of the pipeline, the overall area potentially affected will be about 192 ha.
This, however, is a small percentage of the fishing ground (~4.3%) in the
study area. The potential impact to fisheries resources/production is thus
minimal. With the implementation of good dredging practices recommended in
Section 6.7, water quality impacts and hence impacts to fisheries are could
be further reduced and the impacts will be insignificant. No other mitigation measures are required. |
Destruction and
disturbance of nursery and spawning grounds |
The study area
is known to be a spawning ground for several important commercial fisheries. |
Provided that
the good dredging practices recommended in Section 6.7 are adhered to, water
quality impacts and hence impacts (direct impacts attributable to elevated
suspended solids and indirect impacts such as reduced dissolved oxygen) to
fisheries are insignificant. No other
mitigation measures are required. |
Impact on
fishing activity |
A dredging
vessel (s) will be required to dredge a trench for the pipeline and this
vessel may interfere with fishing activity in the study area. |
The study area
has an extremely high volume of marine traffic (e.g., Urmston road major
shipping channel; ~ 30 hydrofoil ferries pass through the area daily;
river-going vessels to the RTT; and numerous trawl vessels) and ( |
Impact on
aquaculture activity |
Dredging of the
trench for the pipeline may lead to elevated suspended solids. |
Insignificant
elevated suspended solid concentrations are predicted and higher levels will
be highly localised (i.e., within the works area/ dredging location).
Elevated suspended solid concentrations are not predicted at the Ma Wan FCZ
(see Section 6) which is located >14km from the PAFF and dredging
operations on the FCZ are considered to represent an insignificant impact. |
AFCD (1998). Port Survey 96/97. Agriculture,
Fisheries and Conservation Department,
AFCD (2001). Consultancy Study on Fisheries
and Marine Ecological Criteria for Impact Assessment. Agriculture, Fisheries
and Conservation Department,
AFCD (2003). Port Survey 2001/2002. Fisheries Management Division, Agriculture,
Fisheries and Conservation Department, Government of HKSAR.
ERM (1998). Fisheries Resources and Fishing Operations in Hong Kong Waters. Prepared for AFCD.
ERM (2005). Detailed Site Selection Study for a Proposed Contaminated Mud Disposal
Facility within the Airport East/East of Sha Chau Area. Environmental Impact
Assessment and Final Site Selection Report. Prepared for the Civil
Engineering and Development Department, Government of HKSAR.
Hyder (1998). Supplement EIA for the Proposed Sand Extraction from the Brothers Marine Borrow Area. Prepared for CED.
Meinhardt (2006a). Environmental Monitoring and Audit for
Contaminated Mud Pit IV at
Meinhardt (2006b). Environmental Monitoring and Audit for
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Mouchel (2005a). Environmental Monitoring and Audit for
Contaminated Mud Pit IV at
Mouchel (2005b). Environmental Monitoring and Audit for
Contaminated Mud Pit IV at