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Shellfish

Scallops

Scallops are bivalves; they have two hard shells and a soft body. They are benthic animals; they spend most of their time on the sea bottom. Scallops mostly stay in underwater grass beds on a soft, shallow sea floor. Scallops use jet propulsion to move; they quickly open and close their shells, squirting the water out of the shells, moving in spurts. These invertebrate animals have a life span of about 1½ to 2 years.

Paua

Not to be taken on Scuba or Self Contained Breathing Apparatus
The shell of Paua (abalone) has a convex, rounded to oval shape, and may be highly arched or very flattened. It is generally ear shaped, presenting two to three whorls. It also has has a series of holes near the back edge, that are in fact respiratory pores that are used for the escape of water from the gills.

The colour of the shell is very variable  and may reflect the animal’s diet.The iridescent inner shell varies in colour from silvery white, to pink, red and green-red, through to  deep blues, greens and purples.

Oysters

Oysters provide habitat for many marine species and live mainly in the intertidal and subtidal zones Their hard surfaces of oyster shells and the nooks between the shells provide places where a host of small animals can live.  An oyster reef can increase the surface area of a flat bottom 50-fold.

An oyster’s mature shape often depends on the type of bottom to which it is originally attached, but it always orients itself with its outer, flared shell tilted upward. One valve is cupped and the other is flat. Oysters usually reach maturity in about 3 years

Mussels

There are 3 species of mussels:

 

The Green Lipped Mussel (also known as Pen canaliculus, the New Zealand mussel, the green shell mussel, or kuku, or kutai) is a bivalve mollusc. Green-lipped mussels contain a unique combination of fatty acids that are not found in any other marine or plant life. It differs from other mussel species in that it has a dark brown/green shell, a green lip around the edge of the shells and only has one adductor muscle. It is also one of the largest mussel species reaching 240 mm in length. Studies show these mussels can assist in the repair of damaged joint tissues and show anti inflammation properties  These  mussels are widely farmed in New Zealand.

The Horse Mussel has a large fragile shell and can grow up to 390 mm in total length. It has 6-12 ribs running longitudinally down its shell. Each rib bears translucent cup-like projections. The shell does not close at the flared end  and the dark-rimmed white flesh can be seen inside.

The Blue Mussel lives in intertidal areas attached to rocks and other hard substrates by strong (and somewhat elastic) thread-like structures called byssal threads; these are secreted by byssal glands located in the foot of the mussel.The shell is smooth with a sculpturing of fine concentric growth lines but no radiating ribs. The shells of this species are purple, blue or sometimes brown in color.

 

Kina

Their diet mainly consists of kelp, and if Kina populations become out of control, kelp forest can be entirely eaten away, leaving bare rocks, also known as Kina Barrens. Kina also eat Algae and Plankton. The spines, long and sharp in some species, protect the urchin from predators. The spines inflict a painful wound when they penetrate human skin, but are not dangerous.

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