Targeted non-native species

- Ciona intestinalis
- Mytilopsis sallei
- Mytilus galloprovincialis
- Crepidula oynx
- Sphaeroma walkeri
- Bugula californica

Distribution of non-native marine species

- Kat O: Sphaeroma walkeri (destructive sampling)
- Lai Chi Wo (Marine Park): Sphaeroma walkeri (destructive sampling)
- Tung Ping Chau (Marine Park): Ciona intestinalis (visual observation) and Sphaeroma walkeri (destructive sampling)
- Grass Island: Sphaeroma walkeri (destructive sampling)
- Hoi Ha Wan (Marine Park) : No non-native species
- San Mun Tsai, Tolo Harbour: Sphaeroma walkeri (destructive sampling)
- Sai Kung: Sphaeroma walkeri (destructive sampling)
- Tun Mun: Mytilus sallei (destructive sampling) and Sphaeroma walkeri (destructive sampling)
- Ma Wan: Mytilus sallei (destructive sampling), Crepidula oynx (destructive sampling) and Sphaeroma walkeri (destructive sampling)
- Tsim Sha Tsui, Victoria Harbour: Crepidula oynx (photoquadrats and destructive sampling)
- Kwun Tong, Victoria harbour: Mytilus sallei (photoquadrats and destructive sampling), Ciona intestinalis (photoquadrats and destructive sampling), Crepidula oynx (destructive sampling) and Sphaeroma walkeri (destructive sampling)
- North Point, Victoria Harbour: Ciona intestinalis (photoquadrats and destructive sampling)
- Shau Kei Wan, Victorial Harbour: Ciona intestinalis (destructive sampling) and Shpaeroma walkeri (destructive sampling)
- Po Toi O: Sphaeroma walkeri (destructive sampling)
- Joss House Bay: Ciona intestinalis (visual observation), Crepidula oynx (photoquadrats and destructive sampling) and Sphaeroma walkeri (destrcutive sampling)
- Tai Tam: Ciona intestinalis (photoquadrats and destructive sampling) and Sphaeroma walkeri (destructive sampling)
- Aberdeen: Ciona intestinalis (photoquadrats and destructive sampling) and Sphaeroma walkeri (destructive sampling
- Po Toi: Mytilus sallei (destructive sampling) and Sphaeroma walkeri (destructive sampling)
- Sok Kwo Wan: Sphaeroma walkeri (destructive sampling)
- Chi Ma Wan: Crepidula oynx (visual observation) and Sphaeroma walkeri (destructive sampling)

 

Project Description...

What are non-native species?

Non-native species (also called "alien species", "invasive species", "introduced species", "exotics"), according to the European Union definition, are species that exist 1) outside their natural distribution area, and 2) threaten biological diversity. They have been introduced to the area through means of dispersal such as hull fouling and ballast water of shipping vessels, aquaculture, and aquarium trade. They are a major threat to the conservation of marine ecosystem with a constant increase of biological invasions through global transport and commerce.

Why do they matter to us?

Non-native species are a major threat to the conservation of marine ecosystems with a constant increase of biological invasions through vectors such as ballast water, hull fouling, aquaculture, and aquarium trade (Carlton & Geller 1993, Ruiz et al. 2000, Gollasch 2006, Mineur et al. 2007, Leung and Dudgeon, 2008). Non-native species often cause negative impacts on biodiversity (Rhymer & Simberloff 1996, Cohen & Carlton 1998, Neill et al. 2006), economy (Larsen 1978, Kuris & Culver 1999) and human health (Van Dolah 2000). These non-native species can cause an impact on local biodiversity through predation, competition, parasites, habitat modifications and genetic effects (Rhymer & Simberloff 1996, Manchester & Bullock 2000). In some cases biodiversity could increase (Castilla et al. 2005), but what happens more frequently is a decrease in local species diversity (Manchester & Bullock 2000, Englund 2002, Grosholz 2002).And being one of the largest marine ports world-wide, our knowledge about marine non-native speceis in Hong Kong is rather scarce.

What are we doing?

In order to manage non-native species and to protect local marine communities, it is crucial to identify these species and to monitor their establishment and distribution. However, very little documentation exists. This study aims to assess the current distribution, abundance and population status of the previously reported non-native species in Hong Kong.

- a comprehensive map of non-native marine species

- temporal variation in their abundances

How can this help?

The results of our project not only detail the current situation of the occurrence of the non-native species in our marine environment, but it provide information on the most abundant and potentially invasive species. The list of these invasive species will be highly useful for us to manage these species in order to protecting and conserving the local marine biodiversity.

Status in 1980's

Six invertebrate species were described as introduced to HK in Morton’s study (1987): Sphaeroma walkeri, Ciona intestinalis, Crepidula onyx, Bugula californica, Mytilopsis sallei, and Mytillus galloprovincialis. The isopod S. walkeri and solitary ascidian C. intestinalis were well established by the early 80’s in Victoria and Tolo Harbours and widely distributed in Hong Kong (e.g. Tai Tam, Kat O). The snail C. onyx, the bryozoan B. californica, and the mussels M. sallei and M. galloprovincialis were first introduced in the late 70’s around Victoria Harbour and Tsing Yi. Later surveys from 1980-1989 reported the presence of S. walkeri, C. onyx and M. sallei in Wu Kai Sha, and C. intestinalis and S. walkeri in Wong Shek. However, large parts of Hong Kong were not included in these studies such as the estuarine zone in western Hong Kong and the oceanic zone of eastern Hong Kong (e.g. Sai Kung), therefore the distribution of non-native species in these areas was largely unknown, and the historical data may not reflect current distribution patterns.

Current status..

Photos taken by Wong CY, Astudillo JC unless otherwise captioned. If you have any questions, please email us.

 

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