Marine pest response in Fiordland proving successful
Undaria on hull of boat on hoist in Wellington – Photo: Lesley Patston, MPI
Marine pest response in Fiordland proving successful
A joint-agency response to the discovery of Undaria, a marine pest, in the pristine waters of Fiordland is proving successful on several fronts.
Undaria is an invasive Asian seaweed that was first discovered in New Zealand waters in 1987. It is now found in most ports and easily spreads attached to the hulls of vessels or on mooring lines and equipment.
During a routine marine biosecurity inspection in early 2010, Department of Conservation (DOC) staff spotted a single mature Undaria plant on a mooring rope in Sunday Cove at Breaksea Sound, Fiordland.
Environment Southland, DOC, and the Ministry for Primary Industries (MPI) with support from the Fiordland Marine Guardians swiftly launched a joint-agency response. A preliminary survey of high-risk areas in Fiordland found hundreds of juvenile Undaria plants in Sunday Cove, but none elsewhere.
An intensive removal programme was put into action and will continue until 2015. Currently, dive teams survey the eight hectare search area three to five times a day for four days, every four weeks or so. To date, 1887 Undaria plants have been removed.
Environment Southland Biosecurity Manager Richard Bowman said a big part of the programme’s success has been in its inter-agency coordination and cooperation. “Lots of prior planning for this type of situation had been done between the agencies at a policy level and this meant the response was initiated quickly and relatively easily. It’s been a fantastic collaboration,” he said.
Innovation is another aspect of the programme’s success. In June 2011 approximately 35,000 kina were collected from nearby Fiordland waters and transferred to Sunday Cove to act as a bio-control agent. Kina is a native sea urchin that grazes on seaweed. The plan for it to help clear existing growth to make it easier for the dive teams to find Undaria plants, has worked well.
Response Manager Derek Richards said the idea of using kina as a control agent was researched prior to their transfer, but that it was an unconventional and untested method that had never been done before. “Giving it a go” was a credit to the response’s open-minded approach.
“The success of the response is in the joint-agency, multi-method approach and while the role of kina is hard to quantify, it shouldn’t be underplayed,” he said. “Undaria is palatable to kina and it’s likely they’ve also consumed the early microscopic stage, which can remain in the marine environment for up to two-and-a-half years.”
Since the transfer of the kina to Sunday Cove the amount of Undaria has reduced significantly. In 2012, one mature plant and 142 juveniles were detected; in 2013 only three juvenile plants were found.
The results to date are very encouraging and while it is early days the response team is cautiously optimistic that Undaria can be eradicated from Sunday Cove. If achieved, it would be a world first from the natural seabed.
The response has been resource-hungry and expensive. So far, the agencies have spent nearly $400,000 in operational costs alone. Richard Bowman said while the success of the response to date would seem to justify the cost, the situation was preventable. He said the ultimate success of the eradication programme and keeping Undaria, and other marine pests, out of Fiordland for the long term will depend, largely, on the cooperation of the boating and yachting communities.
“We don’t want to be in the business of cure, we want to be in the business of prevention. So we really need the support of vessel owners to ensure they don’t bring Undaria in from infected ports – Auckland, Marlborough, Lyttleton, Port Chalmers, Bluff, you name it,” he said. “The situation is preventable.”
There are a number of ways a boat owner can help halt the spread of Undaria and other marine pests. It is essential they clean their hull and marine equipment before entering Fiordland and that they do not remove any seafood from Sunday Cove as it may be infected with Undaria spores. More information is available online: www.biosecurity.govt.nz/fiordland or www.es.govt.nz/environment/pests/marine
Undaria Programme – General
(Undaria pinnatifida) is a native seaweed from North
East Asia and is now found in temperate Atlantic and pacific
Oceans and in both hemispheres as a result of international
shipping and mariculture activities.
• Undaria was first reported in New Zealand in 1987, where it was discovered in Wellington Harbour. Its subsequent spread around mainland New Zealand over the past 25 years has led to concerns about the negative impact it may have on algal biodiversity.
• During a routine biosecurity inspection in 2010, Department of Conservation staff observed a single mature Undaria individual on a mooring rope in Sunday Cove, Breaksea Sound, Fiordland.
• A joint-agency response was immediately initiated with a team of experts from the Ministry of Primary Industries, Department of Conservation & Environment Southland (MPI, DOC & ES) along with support from the Fiordland Marine Guardians (FMG).
• A preliminary survey of high-risk sites throughout southern Fiordland was conducted in July 2010.
• Undaria was only found in Sunday Cove, however there were a large number of immature individuals found there.
• Dive surveys in Sunday Cove and the surrounding area are being undertaken, approximately every four weeks, in which Undaria is manually removed
• The size of the search area is 7.97 ha.
• In total, 1887 Undaria individuals have been detected and removed since the inception of the response.
• In June 2011 ~35,000 kina (native sea urchin) were transferred into Sunday Cove as a bio-control agent.
• Kina graze on seaweed, and over the past 18 months these urchins have gradually eaten their way through some of the search areas. The kina successfully reduced the cover of native seaweeds, making searching the area easier.
• The kina are also likely to have contributed to the removal of the microscopic stages (gametophytes) of Undaria, which in turn helps prevent future generations from establishing.
• The microscopic life stage of Undaria’s lifecycle can persist in the marine environment up to ~ 2.5 years.
• Since the start of 2013 only three juvenile Undaria individuals have been found and removed. In contrast, 142 Undaria juvenile individuals were removed during 2012.
• The last mature Undaria sporophyte was detected in January 2012.
• During May of this year the joint-agency Response Strategic Leadership team met and agreed that the programme should continue in its current form (no scaling back) until at least January 2015.
• Based on progress and the information available to them, the response team agency members from ES, DOC and MPI, and the Guardians believe local elimination is achievable, and urge boaties to play an active part in ensuring no more Undaria, or indeed any other marine pests, are transferred to the Fiordland Marine Area.
• It is hoped that within the next 1–2 years, Fiordland will once again be free of Undaria. This will be significant for the area’s unique marine biodiversity, as well as its important commercial and recreational fisheries.
Any boaties planning a trip to Fiordland, can help to protect it from further threats by checking their vessel’s hull before travel:
• If it’s fouled, clean it.
• Ensure your antifouling paint is thoroughly applied and effective.
• Check, clean and dry any mooring lines and buoys, kayaks and any other marine equipment before using them in Fiordland’s waters.
• Remove all marine debris such as weeds from diving gear and rinse and soak gear in fresh water. Allow to air dry for a few days if possible.
• Keep an eye out for any unusual marine life or events such as mass deaths of fish. Note the location, take a sample if you can and immediately call MPI’s freephone number 0800 80 99 66.
If visiting the Sunday Cove area, please also
• Do not remove seafood from the Sunday Cove area. Shellfish may have been infected with Undaria spores and removing them may spread Undaria to other areas. The kina placed in Sunday Cove are playing a key part in the elimination programme.
• Do not move lobster pots out of the Sunday Cove area, as they may be infected with Undaria spores.