Divers conducting marine surveillance in February discovered an unidentified species at the Jackson Bay wharf. The organism has been tentatively identified as Potamilla alba, a species of marine worms.
Details of the Discovery
The worms were found in high concentrations around the wharf, with densities reaching up to 38 worms per 10 square-millimetres
. Environmental science group manager Shanti Morgan described the specimens as dead white
in colour.
The worms measure 75mm in length and possess gills that reach up to 10mm long. Whereas the identification is current, biosecurity manager Emily Rutherford-Jones noted it remains the best estimate based on one taxonomist’s opinion
and is yet to be confirmed.
Biosecurity and Environmental Impact
According to the World Register of Marine Species, Potamilla alba is typically found in New Zealand waters. As of this, officials indicate the discovery does not represent a significant threat.
Shanti Morgan stated that the worms are unlikely
to be harmful. Biosecurity NZ aquatic team manager Mike Taylor concurred, stating the species does not represent a biosecurity concern
.
Pathways of Arrival
Officials believe the species arrived at the wharf via ship anchors, identifying boats as a key risk pathway
. The specific location of the worms underneath the mooring may be linked to the behavior of the species.
A council marine surveillance report indicates that Potamilla alba are known to form dense clusters that can be dredged in quantity by fishing boats
. This characteristic may explain why they have concentrated in that specific area.
Potential Next Steps
Because the identification is currently based on a single taxonomist’s opinion, further verification may be sought to confirm the species. The council could continue to monitor the wharf area to track the density of the clusters.
Future surveillance may also focus on other mooring sites to determine if ship anchors have introduced the species to other parts of the West Coast.
Frequently Asked Questions
What is Potamilla alba?
This proves a species of marine worm, described as dead white in colour and 75mm long, which is typically found in New Zealand waters.
Is the discovery in Jackson Bay dangerous?
No. Experts state the worms are unlikely to be harmful and do not represent a biosecurity concern.
How did the worms likely reach the West Coast?
It is believed they were brought to Jackson Bay on ship anchors, with boats serving as a key risk pathway.
How should local authorities balance the use of maritime wharves with the need to monitor the arrival of new marine species?
