New Moth, Hong Kong Endemic, under immediate threat from habitat loss

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    Due to Town Planning Board giving permission (very likely illegally) for NT Village houses to be built just a few metres form the shoreline at Hoi Ha, there is now an immediate threat to the only known viable colony in the world of this pretty silver and gold "Mangrove China-mark Moth", an undescribed species of Eristena (Lepidoptera: Crambidae, Acentropinae).

    The houses will be within 100m of Hoi Ha SSSI. Planning directives state that sewage and grey water emissions should not take place within 100m of a SSSI. Additionally, the extra load of sewage and grey water will in all probability adversely affect the Hoi Ha Wan Marine Park, one of the best coral communities in Hong Kong. The DPA for Hoi Ha also states that the primary planning intention is to preserve the natural landscape of the area. Please write to Emily Lau (Tai Po North) or your Legco representative a.s.a.p. to voice your concern about the decision made by TPB.

    Further information on the Eristena sp.: CRA Eristena sp nov (nr. argentata) [Mangrove China-mark Moth]

    This species is closely allied to E. argentata Yoshiyasu, 1988, but has a complete f/w medial fascia and several differences in the hindwing not visible in this photo – including a broader medial band and four, not two or three tornal spots. A/Prof. Dr. Yen Shen Horn, National Sun Yat-sen University, Kaohsiung, Taiwan, who is a specialist on the Acentropinae, has written (pers. comm.) to say that this species, and another undescribed species in Taiwan are both allied to the Japanese Eristena argentata, whose larvae feed on algae growing on the roots of mangrove trees.

    Assuming that the Hong Kong Eristena behaves similarly, then at Hoi Ha, there is sufficient mangrove available at and near to the stream / beach intertidal area that, barring destruction of the habitat (very possible due to poor planning enforcement), the species should be safe here. It is worth noting that there are two other Hong Kong records for this moth species, one from near Tung Chung, and another at an undisclosed coastal locality; both of a single individual photographed by day near mangroves, and both records posted on

    However, the Hoi Ha site remains the only site with more than one individual recorded, thus hosts the greatest world population for this species. In IUCN Red List terms, this species currently would be classified as Critically Endangered, based upon criteria of restricted range (both area of occurrence and occupancy), limited population size and immediate threat to its habitat.


    Article by Cheung Chi-fai in today's S China Morning Post includes:

    An endangered moth that is unique to Hong Kong could stand in the way of plans for a small-house development in an ecologically sensitive part of Sai Kung that some residents say should not be allowed for fear of marine pollution.

    The mangrove China-mark moth was sighted last April in the Hoi Ha marine park, where planning permission has been sought for a dozen houses, two of which have received conditional approval, in a development that could grow to 100 houses.

    Moth specialist Dr Roger Kendrick, who made the discovery, said the project could wipe out the only known colony in the world of the fragile species.

    His concerns are the latest to be expressed about the development, which also include possible flooding from changes to the coastline, pollution from septic tanks and destruction of the moths' habitat.

    The [water protection] law – listed in a technical memorandum on drainage discharge – says no new effluent should be allowed within 100 metres of a site of special scientific interest. Hoi Ha was designated as such site since 1989 and became a marine park in 1996 in recognition of its rich coral habitats.


    from Town Planning Board:

    Dear Sir/Madam,

     Comment on Proposed House (New Territories Exempted House),

    Lots 147 S.C and 147 S.D in D.D. 283, Hoi Ha Village, Sai Kung North

    (Planning Application No. A/DPA/NE-HH/13)

    Your comment on the captioned planning application was received by the Town Planning Board on 12 March 2012.  Please note that the application has been withdrawn by the applicant.

    – hopefully not just short term good news



      I am surprised to see the article above about the moth at Hoi Ha. The planned house – note that – a single house – is over 100m from the moth’s habitat and the development, if meeting current planning laws, will NOT impact it. Also the data that we have at the moment is too sparse for it to even be considered for IUCN Red List status. I wish people would get their facts right before publicising like this.


        The drainage ordinance does not stop the discharge of new effluent in a coastal area – it stops the new discharge of prohibited substances. Private houses with septic tanks and soakaways are exempt from this provision. SCMP were wrong in their report


        From moth expert Roger Kendrick – response to anonymous commenter:

        Maybe the following information will help you understand the situation.  I was approached  by the South China Morning Post on the Eristina sp nov (Mangrove China-mark moth) – and agreed that they could use the information posted on the Flickr page (

        This species has been seen three times only, two sightings of single individuals and my record of five adults from Hoi Ha. I've been recording moths in HK since 1994 and have data from almost all significant contributors dating back to the 1960s (over 65,000 records of 2,300 moth species). The world's expert on the group (a Taiwanese Assoc. Professor, Yen Shen Horn, now one of the world's foremost Lepidoptera researchers) identified the species for me. It is undescribed and the known related species (one described from Japan and one undescribed from Taiwan) are mangrove associates whose larvae feed on algae below the water. That the moths at Hoi Ha were recorded on the back of a beach away from the mangrove indicates the moth travels around the areas adjacent to the mangrove to find nectar, thus it is likely that any development close to the beach and back beach areas adjacent to the mangrove will impact upon this species.

        There is, of course, a possibility that the HK species occurs elsewhere, but the increasing amount of survey work being done has not yet found it.  It has not been recorded at Mai Po or Wetland Park, despite fieldwork taking place at the right time of year.  Based on what is known, not guessed, applying the "Precautionary Principle" expounded by the Convention on Biological Diversity and Sustainable Use of Natural Resouces, and using the IUCN Red List Criteria, this species can only be considered to be currently at high risk of extinction due to the small population size, the very limited area of occupancy, the very limited extent of occurrence and the high degree of threat (through habitat destruction of adjacent land and probable ecological impact on the actual site of the moth – the adults appear to need to find nectar from plants on the beachfront, not just within the mangrove).

        I agree that there should be debate about looking specifically for each of HK's rare / endemic / globally significant species, and doing as thorough a job as possible on their ecology. However, where there is data on a HK species of global significance, however limited, don't you think it's better to flag up the issue rather than to let it be lost, knowing that you had it within your reach to make a difference and raise the awareness of the conservation issue?

        The moth in this case is being used as a flagship to highlight general environmental damage – Hoi Ha is recognised for its landscape appeal. The problem with the current HK planning system is that it looks at each planning application as a stand alone proposal, without looking at the cumulative effect that (as in the Hoi Ha case, for example) many new houses would have.  I am sure you are aware of this issue. I would love to be able to go and find extra colonies of the moth species in question, but as I'm an independent researcher, unless someone is willing to sponsor me financially to go and survey every mangrove in HK and some of the mangroves adjacent to HK (what's left of them), I can only use what data currently exists.  

        Conservation has to be a pragmatic mixture of academic and practical approaches to get any results on the ground (or in the air or water). I can't wait another 3 or 4 years for a full survey of the species, only to find that the mangroves and shore vegetation around Hoi Ha, Tai Mei Tuk and so on have been lost, whilst the survey is underway.  Hong Kong has already lost too much through inaction.  If my actions make people in Govt sit up and take notice that there are people who are concerned about the planning process and its effect upon wildlife in HK, then so much the better.  Have you asked yourself why Govt still haven't told the HK public properly that HK is now a signatory to CBD?  If they wont, then it's up to us in the NGO and voluntary sectors to bridge this gap.

        I have cc'd this reply to a number of people around the world who are involved in conservation, either as academics, or through the Govt. / NGO / voluntary sectors. I'd welcome any opinions on the direction the NGO / voluntary sectors should be going in HK. I look forward to all of us in HK getting a better understanding of how we should try and make a better case of conservation in HK.



        Dear Anonymous

        Indeed – let’s talk facts.

        Fact 1 – The statement you have made in your post concerning the 100 metre spacing and the status of applications is factually incorrect. Very few people know where the moth was found and we were present at the time. How can you claim to know?

        Fact 2 – The SCMP article does not mention IUCN status.

        Fact 3 – Applying the “Precautionary Principle” expounded by the Convention on Biological Diversity (to which HK is a recent signatory) and using the IUCN Red List Criteria, this species can be considered to be currently at high risk of extinction due to the small population size, the limited area of occupancy, the limited extent of occurrence and the high degree of threat (through habitat destruction of adjacent land and probable ecological impact on the site of discovery). The Moth may well qualify for IUCN Red List status and SSSI protection in the future but the recency of its discovery means that the paperwork needs to be conpleted before it can be fully protected, We are anxious to see that the moth is not lost before adequate protections can be put in place.

        David & Nicola NEWBERY



        You, obviously, have not read the Technical Memorandum on Effluent Standards to a sufficient depth to understand what it is saying. You seem to be confusing paragraphs 8 and 9.

        Paragraph 8 describes effluent standards into Inland Waters. Paragraph 8.6 does, indeed say that “the tables do not apply to household septic tanks” but goes on to say that “the general prohibitions still apply”. The “tables” referred to give the concentrations of pollutants and so the implication is that the general provisions apply irrespective of the efficiency of the septic tank system and the quality of the effluent. This information may well be of use to those campaigners wishing to limit development at Pak Sha O, which forms a catchment area for a water supply

        Meanwhile, paragraph 9, which deals with “Discharges to Coastal Waters” and which applies to the Hoi Ha situation, does not contain any exemption from the regulations. Paragaph 9.1 states, quite unambiguously that “No new effuluent will be allowed:……. within 200m of the seaward boundary of a marine fish culture zone or site of special scientific interest, and within 100m of landward boundaries”.

        Thus, the SCMP was quite correct in its reporting and the Govewrnment should not be allowing the siting of new septic tanks within 100 metres of Hoi Ha Wan SSSI.

        David & Nicola NEWBERY


        Anonymous 2:

        Thank you for the comment, though note that you veer towards personal attacks – whilst under cover of anonymity.

        It would have been useful to note if you have a personal stake in Hoi Ha issues, leading to your adopting an air of been well informed whilst making silly errors

        – for instance, no one has said this is the only site for the moth; but the only known viable colony. The precautionary principle is widely adopted; accusations of "pseudo science" are not only insulting to the people posting who have given names, but also indicate ignorance of conservation on your part. Anyone reading this thread will realise Roger Kendrick is a leading scientific authority on Hong Kong moths – a little googling helps reinforce this; readers might question whether you, Anonymous 2, have any comparable expertise.

        Further, your post is fuzzy in referring to other organisations, and other species of conservation significance.


        Response to the Anonymous Poster

        Friends of Hoi Ha have a track record of nearly 10 years of environmental work at Hoi Ha.

        The majority of members of FOHH do not live in Hoi Ha, and they would not countenance the organisation being used for private purposes.

        No members of FOHH have houses for sale in Hoi Ha

        The exemptions for septic tanks (which do not exempt them from the general regulations) appear in Section 8 of the Technical Memorandum, which deals with discharges into Inland Waters.  Section 9, which deals with discharges into Coastal Waters – Hoi Ha Wan – has no such exemption.

        The moth is covered by Dr Roger Kendrick.

        Nicola and Dave Newbery

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