Didymo

1 September 2010

Didymo Long Term Management (LTM) Programme

Introduction

In the last year there has been significant progress made within the Didymo programme, as well as changes to staff and m

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Didymo (Didymosphenia geminata) has been confirmed in the Waimakariri River, MAF Biosecurity New Zealand (MAFBNZ) announced today.

17 September 2009

Didymo Long Term Management (LTM) Programme

The Didymo LTM Steering Group’s most recent meetings were held on 10^th June and 3^rd September 2009.

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1 May 2009

Didymo Long Term Management (LTM) Programme

The Didymo LTM Programme Steering Group is required to periodically review the Didymo Long Term Management programme, and the Steering Group

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31 October 2008

The purpose of this update is to keep you informed about recent work in support of the didymo long-term management programme.

Responsibility for didymo programme management

From 1 July 2008 the didymo long-term management (LTM) programme became fully operative, and all the programme activities became the responsibility of MAF Biosecurity New Zealand’s Pest Management Group. The key didymo programme contacts at MAFBNZ are listed below.

Didymo Long Term Management Steering Group Update

The Didymo Long Term Management Steering Group met on the 15^th of October. Key topics of discussion included the didymo North Island incursion simulation in Napier in September (see below for further information), regional response planning, and the “Check, Clean, Dry” social marketing programme. The Steering Group has representatives from MAFBNZ, DOC, Fish & Game, Regional Councils, Industry and Iwi and has oversight of the didymo long term management programme.

Didymo North Island Incursion Simulation

A simulation of a North Island incursion of didymo was held at the Hawke’s Bay Regional Council offices in Napier on 26 September. The site chosen for the simulation was Willow Flat on the Mohaka River. The exercise objectives were:

1. To test the Hawkes Bay/East Coast Regional Didymo Response Plan.

2. To test the interface between the MAFBNZ Response Model and a partner Response Plan.

3. To demonstrate MAF Biosecurity New Zealand’s role in a North Island incursion of didymo

Feedback from this has been positive, and has identified opportunities for improvements to response systems and plans. We are looking to run the next simulation in another North Island region early in 2009.

Communications update

There has been a very good uptake of advocacy funding this year, with 15 regions successfully applying for funds to assist them with their summer aquatic pest awareness programmes. Some advocates have already started work!

This summer there will again be advocates at the Wellington ferry terminals (in addition to the permanent advocates at the Picton terminals). They will be starting on the 15^th of November and will work for 3 months over the peak travel period.

We have material available for didymo advocates to use again this year. Again we have the core products available (information packs, pocket cleaning guides, brochures, spray bottles). This year the very popular jelly beans have been replaced by branded lollipops, these will be available for use at events, school visits or local shows.

To order any didymo material contact Matthew at matthew.thorpe@maf.govt.nz

Check, Clean, Dry Advisory Group (CCDAG)

MAF Biosecurity New Zealand have been working on establishing a Check, Clean, Dry Advisory Group (CCDAG) to provide guidance for the check, clean, dry social marketing programme, and to drive the broadening of this message to include all aquatic pests. Membership of the group has been confirmed, and the first meeting is scheduled for early November.

Summary of Check Clean Dry 2007-2008 campaign evaluation

MAF Biosecurity New Zealand commissioned The Nielsen Company to evaluate the success of the Check, Clean, Dry campaign for the summer of 2007-2008. This evaluation was done via an online survey, targeted at waterway users – Fish & Game licence holders, jet boaters, Kayak and boating clubs, and 4WD and tramping clubs. 2695 surveys were completed, and the data was weighted so it was comparable with the 2006-2007 survey.

The key message from this evaluation was that there have been increases in awareness of the phrase “Check, Clean, Dry” and increases in freshwater users seriously considering how they can stop didymo spreading and making an effort to check, clean, dry. Fewer people than in 2007 consider didymo a threat to their sport – overall didymo has not had a major impact on participation in sporting activities.

Key facts for freshwater users surveyed in 2008:

• 99% are aware of didymo
• 98% have seen some of the communications material, e.g. signs, posters
• 37% have been in didymo infested waters (72% of South Islanders and 18% of North Islanders)

These results highlight that although there has been an improved level of uptake of the check, clean, dry message it is still important for freshwater users to remain vigilant to the risks of spreading didymo, especially so for the 18% of North Islanders that have been in an infected South Island river.

The survey next year will test awareness and behaviour in relation to didymo and other aquatic pests to inform the ongoing development of the Check, Clean, Dry campaign so that it addresses all aquatic pests.

For more information about didymo visit our new website at www.biosecurity.govt.nz

To report an exotic pest or disease, call the MAF Emergency Pest and Disease Hotline:

0800 80 99 66

If you do not wish to receive these updates please email didymo@maf.govt.nz with ‘Unsubscribe’ in the subject line.

26 June 2008

The purpose of this update is to keep you informed about the work underway in support of the didymo long-term management partnership.

Responsibility for didymo programme management

From 1 July the didymo long-term management (LTM) programme and associated activities will formally become the responsibility of MAF Biosecurity New Zealand's Pest Management Group. Corinna Bennett is the new Didymo LTM Coordinator.

Didymo research completed

MAFBNZ has now completed its didymo research programme.

Gemex™ Impact on Non-Target Species

Gemex™ concentrations were assessed for the short term effects of Gemex™ on a range of non-target species. The toxicity data showed that sensitivity to Gemex™ increased as exposure times and Gemex™ concentration increased, with amphipods being the most sensitive of the species tested, followed by trout and bullies.

Water hardness also had a significant influence on copper toxicity to non-target species with survival being greatest at higher water hardness levels. Predictions were that even in soft water there would be minimal impact on dwarf galaxias, koura and snails. It remains unknown whether increased water hardness will decrease the toxicity of Gemex™ to didymo.

There was no significant bioaccumulation of copper in adult koura exposed to high concentrations of Gemex™ for up to 8 hours, suggesting that risks to humans and other predators consuming koura after a Gemex™ treatment of a waterway is likely to be minimal.

Long time effects of Gemex™

An assessment of long term (10-11 months post -treatment) effects of Gemex™ was undertaken at the site of the small river trial of early 2007. The review found that there was no evidence of long-term adverse effects of a single dose of Gemex™ on the non-target species tested. Although trout were affected in the short-term, trout densities had returned to near pre-treatment levels 11 months afterwards. Copper concentrations in the water and fish were also within acceptable drinking water, human health and protection of ecosystems guidelines by this time.

Multiple doses of Gemex™ should be more effective than a single dose but may also elevate impacts on non-target species. This needs to be taken in to account when considering the use of Gemex™ to control didymo in a river or stream.

Didymo-Gemex™ decision support tool

A decision support system has been developed to assist regions wishing to assess the feasibility of the use of Gemex™ in specific waterways.

Didymo knowledge sharing tools in place

The didymo knowledge sharing project is now complete. The project has delivered three tools.

The quick guide

This hard copy folder provides summaries of key information for the long-term management of didymo and guidance on how to find the complete set of information.

The electronic library

This web-based tool, didymo.net, contains the authoritative knowledge that is available to be shared amongst didymo long-term management partners to assist them in making management decisions about didymo.

The shared workspace

This is an internet based forum for discussion and informal sharing of information among didymo long-term management partners.

The internet sites are not publicly accessible. Password access is available to those partners who are directly involved in the management of didymo. Applications for access should be made to Corinna Bennett, Didymo Long-Term Management Programme Coordinator, corinna.bennett@maf.govt.nz

Communications update

The MAFBNZ communications team attended the Hutchwilco Boat Show in Hamilton last month. This was very successful, with the Check, Clean, Dry message very well received. Next month we will be attending the Christchurch Boat show. We think this is an important event to attend as it is mainly attracts trailer boat owners.

The ACNeilson didymo summer campaign evaluation is due for completion at the end of July. Partners will receive an outline of the results. The results will give us an indication of areas that are working well, and areas that need more attention. This information will be valuable when planning your upcoming summer programmes.

The didymo social marketing material will again be available this financial year. We are planning on refreshing some of the items such as the brochure; however the messages will stay the same.

Process for reporting suspected didymo finds

The following flow chart illustrates the process for when a member of the public has a suspected didymo find. It is important that if a member of the public reports a suspect find to your organisation, either they or your organisation rings the 0800 number to ensure this information is getting to the correct person.

To slow the spread of the invasive alga didymo and other aquatic pests in New Zealand waterways, MAF Biosecurity New Zealand requires all used freshwater fishing equipment brought into New Zealand to be clean and dry.

From mid-October 2007 MAFBNZ's Import Health Standard for Equipment associated with Animals or Water will be updated to require MAFBNZ staff to treat all used freshwater fishing equipment they determine or suspect is NOT COMPLETELY DRY (inside and out), regardless of whether it has been cleaned before coming to New Zealand.

Felt-soled waders and boots are of particular concern. Recent research has revealed these items pose a particularly high-risk of spreading didymo as they are likely to come into direct physical contact with didymo cells (e.g., stepping on or brushing against algal mats) and the thick, absorbent and slow-drying nature of the material encourages cell survival, increasing the risk of spread between waterways.

Treatment for absorbent items such as felt-soled footwear takes time and the person bringing them to New Zealand may need to:

• Wait at the airport until the item is treated, which could be several hours even if the treatment facility is close by; OR
• Arrange for a courier to collect the item from a MAFBNZ treatment facility (at their own expense); OR
• Collect the item from the treatment facility, during their visit or when they depart New Zealand (only if leaving from same port); OR
• Reship the item/s back to their home address at their own expense; OR
• Authorise MAFBNZ to destroy the item/s (no cost).

Depending on the item there are a number of treatments available, including cleaning/soaking in a solution of detergent and water, soaking in hot water, or freezing until completely solid. MAFBNZ staff will determine the most appropriate treatment for the item.

To avoid this inconvenience, anglers coming to New Zealand should consider bringing rubber-soled footwear.

Good freshwater hygiene is important for everyone. Travelling anglers have an important role to play in protecting the environments they visit.

If you are moving between waterways, you must 'Check, Clean, Dry' all equipment you have used. Research has shown this is the best way to slow the spread of didymo and other aquatic pests. Detailed cleaning instructions for specific items such as felt-soled waders have been developed.

New Zealand rivers offer some of the best fishing in the world. Help us to keep it that way.

Page last updated: 25 June 2008

24 December 2004

24th December 2004

Summary

1. Major points to note on Biosecurity New Zealand's (BNZ's) response to the detection of a freshwater alga, Didymosphenia geminata (Didymosphenia), in two Southland rivers, include:

• BNZ convened a Technical Advisory Group to assess impacts and identify appropriate management options;
• Didymosphenia is not able to be eradicated in the short term although it should be possible to slow its spread;
• BNZ has decided to initiate measures to attempt to contain Didymosphenia to affected rivers to give Biosecurity New Zealand (BNZ) time to determine longer-term management options;
• Containment measures will consist of a vigorous awareness campaign supported by the Unwanted Organism powers of the Biosecurity Act 1993
• A recently completed survey has indicated with a high probability that Didymosphenia is not present in the surrounding rivers that have been sampled. This adds additional weight to ensuring the measures to attempt containment are robust.

2. BNZ is continuing to work closely with Environment Southland, Fish and Game, Department of Conservation and Meridian Energy on this issue.

Background

3. Brief history:

• Didymosphenia is a freshwater alga detected in two Southland rivers, the Waiau and the Mararoa;
• Didymosphenia was first detected on 15 October 2004 during routine surveys conducted on behalf of Meridian Energy;
• It is considered to be a recent new introduction to New Zealand;
• Anecdotal information from overseas suggests that the alga could have ecological, aesthetic and economic impacts as well as being a nuisance from a human health perspective;
• Many of New Zealand waterways may be susceptible to invasion; and
• BNZ has been involved since 22 October 2004.

Initial Response

Information collection

4. BNZ has convened a Technical Advisory Group (TAG) to assess the impacts of Didymosphenia and identify appropriate management options. The TAG consisted of three local experts from NIWA and the Department of Conservation and two international experts (via teleconference).

5. The TAG has considered that:

• Didymosphenia is an exotic organism to New Zealand;
• There is no known eradication method at this stage;
• There are definite grounds for concern in terms of potential impacts for New Zealand, based on observations in the northern hemisphere, including impacts on the food chain within the rivers;
• The algae may already be present in other streams; (however microscopic sampling subsequent to the TAG meeting has not detected Didymosphenia outside of the Waiau and Mararoa rivers);
• Didymosphenia is likely to have been present in the Waiau and Mararoa Rivers for at least two years and has been blooming in these rivers for at least the last three months; and
• The presence of the algal blooms in the river systems will significantly increase the likelihood of spread to unaffected rivers.

6. The TAG has recommended that BNZ undertake actions including:

• Containment of Didymosphenia to the existing affected rivers;
• Assessment of the extent of Didymosphenia outside its known locations-with specific attention to the microscopic stage; and
• Research to assess:
  • the efficacy of potential methods to treat boats, fishing gear and other items coming in contact with the affected rivers
  • habitat preferences and environmental conditions that trigger blooms
  • the likely location around New Zealand where Didymosphenia could establish and bloom

Management programme

Containment

7. The principal management activity, at this stage, is containment. This could be achieved either by:

• prohibiting access to the two affected rivers; or
• managing the movement of gear, equipment and other items that have been in contact with affected rivers.

8. BNZ officials decided to manage the movement of equipment, gear and other items, rather than prohibit access, because the only way to effectively prohibit human access is to have a Biosecurity Emergency declared under Part VII of the Act. For a number a practical reasons outlined below, this is not considered desirable:

• Prohibiting human access would not guarantee that Didymosphenia would not spread from the affected rivers as birds and other animals could potentially spread this organism;
• Access is not a problem, per se, it is the movement of people, equipment, gear, and other items from affected to unaffected catchments that poses the risk;
• This organism cannot be eradicated in the short term and closing two rivers over the long term was considered not practicable;
• The affected rivers are a valuable source of income (e.g. tourism, fishing) and recreation for people in the surrounding area. Closing the rivers could have a significant impact on them without a commensurate benefit as Didymosphenia cannot be eradicated in the short term; and
• Effective containment could be achieved through education of visitors to the rivers about the problem and prudent control measures to take in respect of equipment, gear and items that come in contact with the affected waters.

9. BNZ is proposing to contain Didymosphenia through:

• An awareness programme providing information on Didymosphenia, its impacts and methods to prevent its spread;
• On the ground personnel to disseminate information and assist people to take measures to avoid spreading Didymosphenia from affected to unaffected rivers; and
• Provision of a vehicle with treatment facilities in the affected area, to help people clean their equipment, gear or other items that may have come in contact with affected rivers.

10. The programme will be implemented over the Christmas period to ensure that people using the area are well informed of the problem, their responsibilities under the Biosecurity Act, and how to take action.

Delimitation

11. A survey has recently been undertaken to determine whether the microscopic stage of Didymosphenia is present in the rivers surrounding the affected Waiau and Mararoa rivers (as suspected by the members of the TAG). The survey has not detected any sign of Didymosphenia outside of the Waiau and Mararoa catchments, adding weight to ensuring the measures to attempt containment are robust.

12. Further work will also be undertaken to assess Didymosphenia potential distribution. Information on its current and potential distribution will inform future management decisions.

Research

13. The main research needed at this stage is to determine the efficacy of possible treatment / cleaning methods for equipment, gear and other items that have come in contact with the affected rivers. Due to timing constraints, prior to Christmas BNZ has contracted NIWA to undertake a rapid assessment of the treatment / cleaning methods considered most likely to be effective. After Christmas, BNZ will review the need for a more rigorous assessment of the efficacy of the treatments.

Next Steps

14. Eradicating Didymosphenia is not likely to be possible. The future direction of the programme is likely to involve slowing its spread and mitigating its impacts. To work towards this the proposed next steps are:

• Completing the assessment of treatment methods for equipment used in affected rivers;
• Undertaking a study to investigate Didymosphenia's habitat preferences (an autecology study);
• Determine the likely distribution of Didymosphenia in New Zealand and identify values at risk;
• Determining the management options (with advice from the TAG): and
• Analysing the management options and determining a preferred option.

13 October 2005

Biosecurity New Zealand has become aware of a number of alternative cleaning methods being promoted for cleaning river equipment. This has occurred without consultation with Biosecurity New Zealand, and the methods have not been laboratory tested on Didymo.

There are doubts about the ability of some of the proposed methods to kill Didymo. Not using the approved cleaning methods would put the user at risk of breaching the controlled area conditions where they are in place, as well as potentially spreading Didymo to an unaffected waterway.

Biosecurity New Zealand is working to assess these methods, but reiterates that in the meantime, the approved cleaning methods available at www.biosecurity.govt.nz/didymo are the ones to use. Advice is being developed for recommended cleaning options for specific items and will be online shortly.

If any more cleaning methods are approved, Biosecurity New Zealand will advise of these in a further stakeholder update. In the meantime, the approved measures should be followed. To ensure you do not spread Didymo, wherever possible restrict equipment, boats, clothing and other items for exclusive use in a single waterway. If you are moving items between waterways you must: 1. Inspect: Before leaving the river, remove all obvious clumps of algae and look for hidden clumps. Leave them at the affected site. If you find any later, do not wash them down drains. Treat them with the approved cleaning methods below, dry them and put them in a rubbish bin. 2. Clean: Soak and scrub all items for at least one minute in either, hot (60°C) water, a two percent solution of household bleach or a five percent solution of salt, nappy cleaner, antiseptic hand cleaner or dishwashing detergent. A two percent solution is 200 ml, a five percent solution is 500 ml (two large cups), with water added to make 10 litres. 3. Dry: If cleaning is not practical (i.e. livestock), after the item is completely dry to touch, wait an additional 48 hours before contact or use in any other waterway. Meanwhile, Didymo testing in the North Island is well in hand despite weather delays, and testing in the Southern third of the South Island is due to start today.

Inclement weather and resulting high river levels forced the postponement of some North Island sampling for sample quality and safety reasons, but should be completed by next Wednesday. The delays should not extend the completion date of testing.

Yesterday the survey headquarters moved from Turangi to Alexandra in Central Otago, where planning of the survey for the Southern third of the South Island is being completed. Testing in the Southern third will start today. When testing in that region has been completed, the exercise will be repeated for the central third of the South Island.

All testing should be completed by next Friday, with results announced as soon as possible. Biosecurity New Zealand still intends to release the results by geographic area to avoid any confusion in the event of any positive samples. The results of the survey will guide BNZ’s further short-term containment and longer term management options for Didymo. The controlled areas that have been put in place will be reassessed when the survey is completed.

So far the only rivers to have been confirmed with Didymo are the six rivers mentioned in previous updates – the Waiau (upper and lower), Mararoa, and Oreti Rivers in Southland, the upper Clutha and Hawea in Otago, and the Buller River in the Tasman District.

Biosecurity New Zealand has also requested proposals for potential chemical, biological and mechanical control methods for Didymo. The first draft of an economic impact assessment for Didymo is expected by the end of October.

23 December 2005

Happenings over the summer period.

Coming into the peak summer period Biosecurity New Zealand and other organisations are rampingup their efforts to ensure people are informed of how they can help to stop the spread of Didymo.

Information packs and posters have now been spread far and wide around the North and South Islands. Packs have been sent to a variety of people on databases including Fish and Game licence holders, DOC concessionaires, Coast to Coast multi-sporters and many more.

Many thanks to those people and organisations that have provided databases and have requested packs and posters to hand out in their region.

New river signage is now being erected around the South Island to reflect the move to a South Island Controlled Area and to promote the check, clean, dry message to people using rivers over the peak summer period.

Radio and newspaper advertising will be continuing over the holidays to capture those enjoying a leisurely reading of the paper on their holidays.

There will be a number of personnel on the rivers over the holiday period handing out Didymo information. This includes:

In conjunction with the Environment Southland, LINZ, Contact, Meridian and DOC public education programme; staff will be on the Buller river (between Reefton and St Arnaud) and on the Southland Rivers (based out of Te Anau)

In conjunction with the Otago Regional Council lakes programme; staff will be on the Hawea, Von and Clutha rivers

Fish and Game honorary rangers will be handing out information during the course of their patrols

DOC staff will be handing out information during the course of their work

Meridian Energy staff will be handing out information on the Waitaki canals

Environment Canterbury staff will be handing out information at the Waitaki lakes

Environment Southland staff will be handing out information on Lake Manapouri and Lake

Te Anau in conjunction with their water safety programme

Biosecurity New Zealand would like to thank all those people that have and are continuing to help to spread the check, clean, dry message, your help and local knowledge has been invaluable.

If you would like additional information packs or posters please e-mail emma.monk@maf.govt.nz.