What's growing on down under? - Marine biological baseline surveys reveal 18 new exotic invaders

Nick Gust
NIWA's Nick Gust filming
a wharf pile as part of
the baseline survey and
resurvey programme.
Photo: NIWA

Introductions of non-indigenous marine species into new regions have had significant environmental, economic and social impacts all over the world. This homogenisation of species is now recognised as one of the major threats to ocean biodiversity.

Knowing what native and non-indigenous species are already in our marine environment – baseline information – is vital if we are to manage marine biosecurity risks effectively.

To find out what non-indigenous species have already reached New Zealand's coastal waters, and to gather information on marine biodiversity, the New Zealand Government has implemented a nationwide biological baseline survey and resurvey (repeat survey) programme. This will be done at a range of international maritime traffic hubs throughout New Zealand – places where any new introductions are more likely to appear first.

Biological baseline surveys and resurveys

Initially, 16 locations covering a range of risk classifications were selected. These included 13 major international shipping ports and three marinas of first entry to New Zealand (see Figure 1). An additional eight locations representing a cross section of high-risk and high-value locations have recently been added to the programme (Figure 1).

Sampling methods are based on internationally accepted protocols that allow for a uniform approach and consistent survey design across all locations surveyed.

Figure 1: Ports and marinas where biological baseline surveys and/or resurveys have been undertaken.
Figure 1: Ports and marinas where
biological baseline surveys and/or resurveys
have been undertaken. (red = existing
locations, blue = new locations)

Baseline surveys and resurveys have now been conducted at all of the initial 16 locations selected. These were developed and undertaken by the National Institute of Water and Atmospheric Research (NIWA). The eight recent additions to the programme have only recently been surveyed or are due to be surveyed soon.

The surveys sampled a wide range of habitat types at each of the locations, using a range of sampling techniques, including destructive quadrat sampling (taking samples from a defined area), diver and surface observations, videography, benthic grabs, benthic sleds, a range of baited traps and sediment cores. Sampling effort was distributed in a way that maximised the likelihood of detecting non-indigenous species.

The 23 port surveys completed to date recorded 1,140 species. These comprised 833 native species (73 percent), 84 non-indigenous species (7 percent) and 223 cryptogenic (uncertain or unknown biogeographic origin) species (20 percent). There were also an additional 285 specimens that could not be reliably identified to species as they were damaged or there is insufficient information available to allow identification to species.

About 126 of the species detected so far represent potentially new records for New Zealand. These include 18 non-indigenous species, 15 native species, 92 cryptogenic species and one indeterminate species. Most of the new native and cryptogenic species detections represent species that may be new to science.

While many of the non-indigenous species found have been recorded in New Zealand waters before, about 18 of these new arrivals were being reported for the first time. Because this is the first survey of its type, it is unclear how long these species had been resident in New Zealand before they were found.

Conclusion

This baseline work represents some of the most comprehensive surveying of native and non-indigenous marine species biodiversity undertaken in New Zealand's international shipping ports and marinas. It has significantly increased our knowledge and understanding of non-indigenous marine species and also of New Zealand's marine biodiversity.

This first step toward a better understanding of the scale and scope of marine invasions into New Zealand's coastal waters also contributes toward more accurate assessment of the risks posed by non-indigenous marine species to our native biodiversity, and of the value that New Zealanders obtain from the marine environment. This, in turn, will allow for more effective management of these risks.

For the final reports for completed surveys, look under '2005 Biosecurity New Zealand Technical Papers' at:

Now count them: NIWA staff carrying out the all-important measurements during one of the marine baseline surveys (Photo: NIWA)

Now count them: NIWA staff carrying out the all-important measurements during one of the marine baseline surveys (Photo: NIWA)

Return to:

Page last updated: 30 April 2008