Toggle between tabs to see summaries for each year of monitoring. Links to previous reports are available on the resources page.
Over the last eight years, annual summer checks have been made of 3425 boats, 2970 structures (90% of which were swing moorings) and 441 seabed locations. Most of the effort has focused on the Marlborough Sounds and Abel Tasman National Park coastline, where active boaters are most prevalent. Additional surveys and/or removal programmes for Mediterranean fanworm are undertaken in the main TOS ports and marinas, as part of other council-funded work.
In the 2022/23 survey we checked 502 vessels (mainly recreational), 606 structures and 90 seabed locations. Of the vessels surveyed, 316 (63%) were classified as ‘active’ in the region (e.g. the boat was at anchor), of which 100 (34%) were visiting from outside the TOS. Of the latter, 67 vessels were from marinas in Wellington and 23 from locations considered high-risk for fanworm introduction.
No pests that are new to the TOS region have been found over the six surveys. In terms of established pests, points of interest are as follows:
The Level of Fouling (LOF) status of boats in 2022/23 was similar to previous surveys, with general trends over the last eight years being as follows:
Despite efforts to educate skippers about the importance of regular high-quality antifouling, and vessel cleaning before departure from their home port, the vessel maintenance habits of recreational boaters have not changed appreciably over the last seven years. Of 27% of boaters reporting that they had cleaned their hull since last being antifouled, almost half had cleaned in-water. In-water cleaning is less effective as a management tool than a haul-out and water blast, and can also lead to antifouling coating damage and rapid regrowth of biofouling. In addition, many boaters in-water clean while anchored up in remote and pristine locations; a practice that could exacerbate the spread of pests.
Although most out-of-region boat have only ‘light fouling’, these vessels still represent a particular risk of introducing new pests to the TOS due to fouling of niche areas (e.g. bottom of the keel). Wellington marinas are not currently thought to have pests of significance to the TOS, but if such pests established, those locations could become significant sources for spread into the region. In this respect, the TOS Partnership continues to work to help ensure that visiting vessels:
Are detected before arrival through an effective intelligence system; we use vessel AIS tracking to identify vessels inbound from high-risk regions.
Arrive in the TOS with a ‘clean’ hull where this can be achieved, or are subjected to risk-profiling and an appropriate management response upon arrival.
Changing the maintenance behaviour of within-TOS boaters is critical for reducing the regional spread of established pests. Recognised barriers include a lack of capacity at haul-out facilities in Nelson to enable boaters to be lifted from the water for cleaning or maintenance (currently being rectified), relatively high costs associated with cleaning, and recommendations to avoid in-water cleaning within marina areas. The risk profile of recreational vessels plying the region’s waters will not improve until these issues are addressed. The current practice of in-water cleaning in remote locations provides a potentially significant mechanism for the spread of pests to high-value areas across the TOS. It is important that advocacy or regulation to improve hull hygiene is accompanied by systems and infrastructure to support best practice.
Over the last seven years, checks have been made of 2923 boats, 2019 structures (89% of which were swing moorings) and 248 seabed locations. Most of the effort has focused on the Marlborough Sounds and Abel Tasman National Park coastline, where active boaters are most prevalent. Additional surveys and/or removal programmes for target pests are undertaken in the main TOS ports and marinas, as part of other council-funded work that is not reported here.
In the 2021/22 survey we checked 474 vessels (mainly recreational), 512 structures and 148 seabed locations. Of the vessels surveyed, 329 (69%) were classified as ‘active’ in the region (e.g. the boat was at anchor), of which 75 (27%) were visiting from outside the TOS. Of the latter, 53 vessels were from marinas in Wellington.
No pests that are new to the TOS region have been found over the six surveys. With respect to established pests, points of interest are as follows:
The Level of Fouling (LOF) status of boats in 2021/22 was largely similar to previous surveys, with general trends over the seven surveys being as follows:
Despite efforts to educate skippers about the importance of regular high-quality antifouling, and vessel cleaning before departure from their home port, the vessel maintenance habits of recreational boaters have not changed appreciably over the last seven years. Of 25% of boaters reporting that they had cleaned their hull since last being antifouled, almost half had cleaned in-water. In-water cleaning is less effective as a management tool than a haul-out and water blast, and can also lead to antifouling coating damage and rapid regrowth of biofouling. In addition, many boaters in-water clean while anchored up in remote and pristine locations; a practice that could exacerbate the spread of pests.
Although most out-of-region boat have only ‘light fouling’, these vessels still represent a particular risk of introducing new pests to the TOS due to fouling of niche areas (e.g. bottom of the keel). Wellington marinas are not currently thought to have pests of significance to the TOS, but if such pests established, those locations could become significant sources for spread into the region. In this respect, the TOS Partnership continues to work to help ensure that visiting vessels:
Are detected before arrival through an effective intelligence system; we are increasingly using vessel AIS tracking to identify vessels inbound from high-risk regions.
Arrive in the TOS with a ‘clean’ hull where this can be achieved, or are subjected to risk-profiling and an appropriate management response upon arrival.
Changing the maintenance behaviour of within-TOS boaters is critical for reducing the regional spread of established pests. Recognised barriers include a lack of capacity at some haul-out facilities to enable boaters to be lifted from the water for cleaning or maintenance (currently being rectified), relatively high costs associated with cleaning, and recommendations to avoid in-water cleaning within marina areas. The risk profile of recreational vessels plying the region’s waters won’t improve until these issues are addressed.
Over the last six years, checks have been made of 2449 boats, 1852 structures (90% of which were swing moorings) and 203 seabed sites. Most of the effort has focused on the Marlborough Sounds and Abel Tasman National Park coastline, where active boaters are most prevalent. Additional surveys and/or removal programmes for target pests are undertaken in the main TOS ports and marinas, as part of other council-funded work that is not reported here.
In the 2020/21 survey we checked 502 vessels (mainly recreational), 345 structures and 103 seabed sites. Of the vessels surveyed, 284 were classified as ‘active’ in the region (e.g. the boat was at anchor), of which 64 (27%) were visiting from outside the TOS, primarily from marinas in Wellington (n=45 vessels). It is uncommon to encounter vessels from overseas (only eight checked in six years). In general, many of the visiting boats are found in outer parts of Queen Charlotte Sound.
No pests that are new to the TOS region have been found over the six surveys. With respect to established pests, points of interest are as follows:
The Level of Fouling (LOF) status of boats in 2020/21 was largely similar to previous surveys, with general trends over the six surveys being as follows:
Despite efforts to educate skippers about the importance of regular high-quality antifouling, and vessel cleaning before departure from their home port, the vessel maintenance habits of recreational boaters have not changed appreciably over the last six years.
In the latest survey 30% of boaters had cleaned their hull since their last antifoul, of which nearly half cleaned in water. Over all surveys, around 15% of boaters had undertaken in-water cleaning since last being antifouled. In-water cleaning is considerably less effective as a management tool than a haul-out and water blasting (e.g. some vessels were LOF 5 within a month of being in-water cleaned). Reasons for low effectiveness and rapid regrowth include incomplete removal of fouling, and damage to ablative antifouling coatings, both of which can lead to rapid fouling regrowth.
Out-of-region boaters, while generally having only ‘light fouling’, represent a particular risk of introducing new pests to the TOS due to fouling of niche areas (e.g. bottom of the keel). Wellington marinas are not currently thought to have pests of significance to the TOS, but if such pests established, those locations could become significant sources for spread into the region. In this respect, among the key needs are approaches to ensure that visiting vessels:
Changing the maintenance behaviour of within-TOS boaters is critical for reducing the regional spread of established pests, and understanding current attitudes and barriers to change is part of this picture. Recognised barriers include a lack of capacity at haul-out facilities in Nelson to enable boaters to be lifted from the water for cleaning or maintenance (currently being rectified), relatively high costs associated with cleaning, and recommendations to avoid in-water cleaning within marina areas. The risk profile of recreational vessels plying the region’s waters will not improve until these issues are addressed. Related to this issue, the current practice of in-water cleaning in remote locations provides a potentially significant mechanism for the spread of pests to high-value areas across the TOS. It is important that advocacy or regulation to improve hull hygiene is accompanied by systems and infrastructure to support best practice.
In the over the last 5-years, checks have been made of 1947 boats, 1507 structures (90% of which are swing moorings) and 100 seabed sites. Most of the effort has focused on the Marlborough Sounds and Abel Tasman National Park coastline, where active boaters are most prevalent. Additional surveys and/or removal programmes for target pests are undertaken in the main TOS ports and marinas, as part of other council-funded work.
In the 2019/20 survey we checked 469 vessels (mainly recreational), 349 structures and 53 seabed sites. With a greater focus on active vessels in the 2019/20 survey than previously, the total vessel tally was slightly less than last year but the number of active vessels was relatively high (291). A total of 52 of these vessels were from outside the TOS, of which 79% were from marinas in Wellington.
Out-of-region visiting boats made up 29% of total ‘active’ vessel records, but their occurrence was disproportionate across the two regions, with visitors (mainly from Wellington) being most prevalent in Marlborough. Around 25% of visitors from New Zealand ports originate from outside Wellington. It is uncommon to encounter vessels from overseas (only 6 checked in 5 years).
No pests that are new to the TOS region have been found over the 5 surveys. With respect to established pests, points of interest are as follows:
The Level of Fouling (LOF) status of boats was largely similar to previous surveys, as follows:
The vessel maintenance habits of recreational boaters have not changed appreciably over the 5 years, despite efforts to educate skippers about the importance of regular high-quality antifouling, and vessel cleaning before departure from their home port.
Combined survey data reveal that around 28% of boaters had undertaken a hull clean since their last antifouling. Based on survey data from 2015/16 and 2019/20 (and a 2017 travel-lift study in the TOS), it is apparent that more than half of these vessel were cleaned in-water, often while moored or anchored in high-value areas. In-water cleaning is considerably less effective at a management tool than a haul-out and water blast (e.g. some vessels were LOF 5 within a month of being in-water cleaned).
Out-of-region boaters, while generally having only ‘light fouling’, represent a particular risk of introducing new pests to the TOS due to fouling of niche areas (e.g. bottom of the keel). Wellington marinas are not currently thought to have pests of significance to the TOS, but if such pests established, those locations would become significant sources for spread into the region. In this respect, among the key needs are approaches to ensure that visiting vessels:
Changing the maintenance behaviour of within-TOS boaters is critical for reducing the regional spread of established pests, and understanding current attitudes and barriers to change is part of this picture. One of the recognised barriers is lack of capacity at haul-out facilities in Nelson to enable boaters to be lifted from the water for cleaning or maintenance. Although this issue is now being addressed, the risk profile of recreational vessels plying the region’s waters will not improve until it is fully resolved. Related to this issue, the current alternative practice of in-water cleaning in remote locations provides a potentially significant mechanism for the spread of pests to high-value areas across the TOS. Arguably, it is futile to be advocating or regulating improved hull hygiene without systems in place to support best practice.
In the 2019 survey checks were made of 521 vessels, 401 structures and 47 seabed sites, with a total effort over the four surveys of 2,683 records, comprising 1,478 vessels and 1,158 structures, as well as 47 seabed sites surveyed in 2019. Key results across four surveys were as follows:
Out-of-region visiting boats made up 23% of total records, but their occurrence was disproportionate across the two TOS regions, with visitors comprising ~30% and 12% of boats active in Marlborough and Nelson-Tasman, respectively. In the case of Marlborough, most of the out-of-region boats were from Wellington, especially Mana marina on the Kapiti coast. Very few boats come from other parts of New Zealand, and it is uncommon to encounter vessels from overseas. Findings were assessed in relation to compliance with hull biofouling rules developed by Marlborough District Council and Port Marlborough marinas, revealing that non-compliance is likely for a relatively high percentage of visiting boaters. The results reinforce the importance of direct management of vessel fouling as an integral part of effective biosecurity. A significant challenge is reducing ‘niche’ area fouling on the bottom of vessel keels, especially in situations where the main hull appears well-maintained and free of visible macrofouling organisms.
In 2017/18 we surveyed 544 vessels (mainly recreational yachts and power boats) and 546 coastal structures (mainly swing moorings and jetties), and engaged with 232 active boaters. Key results were:
Survey results illustrate that intensive population control for target pests in vessel hubs is an effective way to reduce vessel colonisation and subsequent vessel-mediated spread. The fanworm has been managed to low densities in Picton/Waikawa, Nelson, and Tarakohe, and was not recorded anywhere outside of these hubs.
By contrast, the more abundant unmanaged pests in these hubs were the ones that were prevalent on vessels. In the absence of Styela clava population control, or continued fanworm control, it can be expected that vessels in TOS hubs will increasingly act as vectors for the within-region spread of multiple marine pests. In addition, the proportion of boats from Wellington was high (17%), illustrating the potential importance of Wellington marinas as source regions for pests to the TOS. Wellington marinas are not currently thought to have fanworm, but if it did establish, those locations would become significant sources for fanworm spread, especially to Marlborough.
Monitoring was conducted over six days during the peak summer season from 27 December 2016 to 30 January 2017. In total we checked 186 boats, 73 associated moorings, and a few other structures (e.g. pontoons, pilings, rock walls). Key findings and implications are as follows:
Vessel monitoring was conducted over six days during the peak summer season, with effort focused on four sub-regions: Port Tarakohe, the Abel Tasman National Park coastline, Pelorus Sound and Queen Charlotte Sound. Biofouling was surveyed on 226 boats in total across these areas, and 135 associated moorings.
Level of Fouling (LOF) scores in the regional survey were as follows:
No pests were found that were new to the TOS region. However, a total of 30% of boats had at least one of the six target pest species present, with an increasing prevalence of pest occurrence with increasing LOF. Pest prevalence appeared related to the duration a given species had been established in the TOS, as follows:
It was often the case that boats with light fouling overall (e.g. a slime layer on the main hull) had well-developed fouling in “niche” areas. Vessel keels are of particular interest in this regard, as on some boats keels provide a large surface that can develop advanced macrofouling and harbour marine pests. This situation primarily reflects that keels may be incompletely coated (or not coated) with antifouling paint during maintenance. The 2015/16 report also summarises the findings of a mail-in boater questionnaire, that sought to understand boater maintenance habits and other behaviours.