Eel grass is a submerged, bottom-rooted, freshwater aquatic herb.
Description
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Leaves are ribbon-like, flat, and up to three metres long.
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Male flowers are large, pollen-filled sacs that are produced at the base of the plant.
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Female flowers are small, green and produced at the end of a very long, spirally coiled stalk that can extend to the water’s surface.
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Viable seed is not produced in New Zealand. Only male plants present.
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Vegetative spread from rhizome fragments.
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Habitats include static to moderately fast-moving water bodies up to 10 metres deep.
What you need to know
Eel grass forms dense stands which may displace native submerged vegetation. It may impede drainage, exacerbate flooding, and recreational water uses. Can cause drowning through entanglement.
Management approach
Eel grass is declared an unwanted organism by the Ministry for Primary Industries (MPI) because it is capable of causing harm to the natural environment, physical resources or human health in Aotearoa/New Zealand.
These species pose a high risk to our environment, economy, recreation, and cultural values.
Rules
Any species declared a pest, including unwanted organisms, cannot be sold or be in a place where plants are being sold. Pest plants cannot be propagated, bred, or multiplied, communicated, released, or cause to be released, or otherwise spread.
Control
Do not attempt to undertake control of eel grass yourself. Report any sightings to us.
Eel grass. Photo credit: NIWA
Eel grass. Photo credit: Paul Champion
