What does it look like?
Japanese mantis shrimp are light grey and can grow up to 185mm. They have two spiny claws used to capture food. This species can be confused with a similar sized native mantis shrimp but can be identified by red/maroon ridges along the middle of the body and a blue and yellow outer tail fan. In the native species, the tail fan is grey and yellow.
Native to the north-western Pacific, Japanese mantis shrimp are most common in the temperate waters of China and Japan. In their native range, they live for around 3-3.5 years. Males reach sexual maturity at 4–5 cm in body length, while females mature at about seven centimetres. Females can brood up to 50,000 eggs and remain in their burrows while caring for the embryos. After hatching, larvae go through several free swimming stages, with a larval life of around two months.
Why is it a problem?
Japanese mantis shrimp prey on a wide range of important kaimoana species, including native shrimps (kōurara/tarawera), crabs, and juvenile fish. They also compete with other crustaceans for food and space, altering benthic communities.
They live in burrows in soft sediments, sand and mud in sheltered bays and estuaries, where their burrowing can change habitat structure. When present in high numbers, Japanese mantis shrimp can significantly restructure benthic communities by displacing other crustaceans.
Control methods
You must notify us if you think you have seen this pest. Please call us on 06 835 9200.
To help protect our environment:
- You must not breed, distribute, release or sell any Japanese mantis shrimp.
- If you catch a Japanese mantis shrimp you must kill it immediately.
- If you’re in charge of any craft in the Hawke’s Bay, you must ensure that the level of fouling on the hull and in niches of the craft does not exceed ‘light fouling’.
- Before moving your boat or other craft to new locations, make sure the hull, anchor chain and all other equipment on board is clean and free of marine pests or other fouling. Think about where you’re taking on or releasing ballast, bilge or holding tank water, or water in any other container such as chilly bins, to avoid spreading marine pests.
You can help prevent the spread of marine pests by:
- Regularly cleaning your boat’s hull –keep fouling growth to no more than a light slime layer.
- Applying a thorough coating of antifouling paint and keep it in good condition.
- Ensure your hull is clean and free of fouling before you travel to a new area.
- Clean and dry any marine equipment (e.g. ropes, lines and pots) before using in a new area.
- Inspect areas on your boat that retain water for signs of marine life.
- Check for aquatic weeds tangled around anchors, trailers and other equipment.
Related links
Notify Council
If you think you've found this pest, please get in touch with our Biosecurity Team at biosecurity@hbrc.govt.nz or call us on 0800 108 838.
Rules
Rule 1
The operator of a vessel entering the waters of the Hawke’s Bay Regional Council must ensure the hull (includes hull area, niche areas and wind and water line) or any structure or navigation aid of any origin, issufficiently cleaned and antifouled so that there is no more than a slime layer and/or goose barnacles.
