Mussels

How to identify mussels

• Green-lipped mussel: a large shell with a green band around the edge (the green lip). Farmed ones are harvested at about 8–10 cm; wild ones vary widely, and old ones can grow to 20 cm or more, and over 240 mm at most.
• Blue mussel: smaller than a green-lipped mussel, with a blue-black shell and no green edge.
• Both grow in clumps, held on by the tough threads of the beard.

New Zealand has 22 species of true mussel, but two are gathered for food. The green-lipped mussel (Perna canaliculus) is the big one, and the one farmed commercially as the Greenshell mussel. It is easy to recognise by the green band around the edge of the shell. The blue mussel is smaller, with a blue-black shell. The World Register of Marine Species lists the native Australasian blue mussel as Mytilus planulatus. New Zealand references, including Te Ara and Te Papa, often call it Mytilus galloprovincialis, and the fishing regulations still use the old name Mytilus edulis aoteanus. Both mussels grow in clumps on rocks and wharf piles, held on by the tough threads of the "beard".

Where it lives in New Zealand

Green-lipped mussels are found around New Zealand but are most common in central and northern waters, where they form dense beds. They live from the middle of the shore down to depths of more than 50 m, on rocky reefs, open coast and wharf piles, and are absent from the Chatham Islands. Blue mussels share the same rocky coasts, from low tide down into the shallows.

Mussels can be gathered all year where open, with closures where they apply; see the limits by area below.

How to gather it

Mussels are gathered by hand at low tide. There is no minimum size for mussels in most areas, so most people take the larger ones and leave the rest to grow.

Mussel limits have changed in some areas, and new intertidal closures in the Auckland Coromandel area include mussels. See the limits by area and the closures below before you go.

Respect rāhui and mātaitai. Kuku have been gathered by Māori for centuries, and several current mussel closures are rāhui put in place by tangata whenua, such as Te rāhui kuku ki tua o Kanawa in Ōhiwa Harbour, which MPI backs with a temporary closure. Mātaitai reserves, such as Te Puna mātaitai, can ban taking mussels altogether. MPI publishes the rules and maps for each customary management area.

Eating

Mussels are usually steamed open with a little liquid, then eaten as they are, in chowder, fritters or a curry. Pull off the beard and scrub the shells first.

Wild mussels are filter feeders, so they take up whatever is in the water, including algal toxins and sewage. Before you gather, check MPI's shellfish biotoxin alerts for that coast. Cooking does not destroy biotoxins. Avoid beds near stormwater drains and sewage outfalls, and don't gather after heavy rain, when runoff carries contaminants into harbours. Regional council water-quality reports, such as LAWA's Can I swim here? or Auckland's Safeswim, show where the water is poor.

Farmed mussels come from areas that are classified and tested under New Zealand Food Safety's shellfish quality assurance programme, and are closed after rain or when toxins are detected. Wild mussels you gather yourself are not tested, which is why the alerts matter.

Symptoms of shellfish poisoning usually start between 10 minutes and 3 hours after eating, and include tingling around the mouth and in the fingers and toes, dizziness and difficulty breathing or swallowing. If you feel unwell, call Healthline on 0800 611 116 or get medical help straight away, and keep any leftovers for testing.

Recipes

• Mussels with rich tomato sauce (Seafood New Zealand)
• Greenshell mussels in coconut curry (Seafood New Zealand)

Good to know

Most mussels New Zealanders eat are farmed. Aquaculture began in New Zealand waters in the 1980s, and green-lipped mussels soon became plentiful. Farmed green-lipped mussels grow fast: in suspended culture they reach about 75 mm in six months and more than 110 mm in a year, much faster than mussels on crowded, wave-exposed wild beds. The farms rely on wild spat, much of it collected on seaweed washed up on beaches in the Auckland (West) quota area.

The wild mussel fishery has a boom-and-bust history. Dredging for mussels in the Hauraki Gulf began in 1927, peaked at more than 2,000 tonnes in 1961, and the beds were so overfished that the fishery closed in 1966. A dredge fishery in Tasman Bay and Kenepuru Sound declined within five years. Since 2019–20, the only commercial wild harvest reported has been mussel spat.

Recreational gathering has dropped. MPI's national panel survey estimated that recreational fishers took about 143,000 mussels in 2022–23, against 342,000 in 2017–18 and 983,000 in 2011–12. These estimates come from a small number of households and are uncertain.

Green-lipped mussels have separate sexes and spawn mainly from late spring to early autumn, when a female can release up to 100 million eggs. They mature in their first year.

Questions

How many mussels can I take?

It depends on the area, and limits have recently been cut in the Auckland Coromandel area, where an intertidal closure also covers mussels. See the limits by area and the closures below.

Do blue mussels count towards the mussel limit?

Yes. The regulations define a mussel as green-lipped, blue or horse mussel, so blue mussels count towards the same limit.

Are wild mussels safe to eat?

There's no blanket answer, because it depends on the water they came from. Check MPI's shellfish biotoxin alerts for that coast, avoid beds near outfalls, and don't gather after heavy rain. Cooking does not destroy biotoxins.

Are farmed mussels different from wild ones?

They are the same species, but farmed mussels grow faster and come from areas that are tested under New Zealand Food Safety's shellfish programme. Wild mussels are not tested.