In December, the Japanese mantis shrimp (Oratosquilla oratoria) was discovered for the first time in the Bay of Plenty region of New Zealand. Officials in New Zealand are investigating why this highly aggressive marine species has appeared in the northern part of the country.
Last week, the Bay of Plenty Regional Council shared on Facebook that researchers captured a Japanese mantis shrimp when they were capturing Asian paddle crabs in Tauranga Harbour, and they were “shocked” by the discovery.
“This is the first time this type of shrimp has been found in the Bay of Plenty region, but it’s not something to celebrate,” local officials said.
The species is known for its loud roars and is nicknamed the “thumb splitter” because of its aggressiveness, capable of breaking through glass of aquariums.
These shrimps have powerful front claws that can deliver a powerful strike to stun invaders or prey in an instant.
The species was first sighted in New Zealand in 2010 in Kaipara Harbour. The closest known location to Bay of Plenty where this species has been found is Thames Harbour.
The Bay of Plenty Regional Council stated in November that it is currently unclear how these shrimps appeared in Tauranga Harbour, but it is possible that they migrated through natural dispersal.
“The marine biosecurity staff of the Bay of Plenty Regional Council have officially confirmed the presence of this species. Preliminary investigations are ongoing, and staff will assess the next steps of the response plan in the coming days,” a council spokesperson said.
The Japanese mantis shrimps are light gray and typically around 18.5 centimeters long. They have two spiky claws used for capturing food. They can be easily mistaken for native New Zealand species due to their body size and color, but the Japanese mantis shrimps have fine reddish-brown lines on their bodies, and their tail fan’s outer surface is blue and yellow (compared to the native species which is gray and yellow).
These shrimps live in caves in sheltered bays and estuaries with soft sediments, sand, and mud. They are native to the northwest Pacific and are commonly found in temperate waters of China and Japan.
The Japanese mantis shrimps prey on shrimps, crabs, and soft-shelled mollusks, and they can alter habitats by digging holes. When they are abundant, they can influence the construction of benthic communities and may compete with other crustaceans for food and space.
While New Zealand sees these shrimps as a threat, in Asian communities including the Chinese community, this shrimp is considered a delicacy known as “seawater prawn” due to its abundant and delicious meat in the abdomen.