Pecten novaezealandiae
Encyclopedia
Pecten novaezealandiae, or the New Zealand scallop, is a bivalve mollusc of the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Pectinidae
Pectinidae
The Pectinidae are a family of bivalve mollusks including the scallop and closely related to the clam and oyster. They are hermaphrodite, and the male gonads mature first. Pectinidae can live attached by means of a filament they secrete, or are simply recumbent. Their valves can propel them...

.

Distribution

Pecten novaezealandiae is endemic to New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

. It is found in the North Island
North Island
The North Island is one of the two main islands of New Zealand, separated from the much less populous South Island by Cook Strait. The island is in area, making it the world's 14th-largest island...

, South Island
South Island
The South Island is the larger of the two major islands of New Zealand, the other being the more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman Sea, to the south and east by the Pacific Ocean...

, Stewart Island, and the Chatham Islands
Chatham Islands
The Chatham Islands are an archipelago and New Zealand territory in the Pacific Ocean consisting of about ten islands within a radius, the largest of which are Chatham Island and Pitt Island. Their name in the indigenous language, Moriori, means Misty Sun...

.

Habitat

Pecten novaezealandiae is found in sand, silt, and mud from low tide level to over 90 m. Large populations are found at depths of between 10 to 25 m. .

Introduction

Pecten novaezealandiae is completely free living, and therefore mobile and somewhat migratory . The two valves
Valve (chiton)
Valve is an anatomical term applied to the shell of molluscs. Although in theory any mollusc shell can be termed a "valve", the word is now most commonly applied to members of two classes of molluscs: the Bivalvia and the Polyplacophora , in other words, to those molluscs whose shells are normally...

 are asymmetric
Asymmetric
Something which is asymmetric displays asymmetry. Specific uses of the term may include:*Asymmetric relation for information on such relations in mathematics and set theory*Asymmetric warfare for information and theories of modern war...

. The left valve is convex while the right is flat. The concave valve has approximately 16 ribs . The colour is variable, however the valves are usually a whitish pink, but sometimes can be a dark reddish brown. Natural predators are sea star
Sea star
Starfish or sea stars are echinoderms belonging to the class Asteroidea. The names "starfish" and "sea star" essentially refer to members of the class Asteroidea...

s and octopus
Octopus
The octopus is a cephalopod mollusc of the order Octopoda. Octopuses have two eyes and four pairs of arms, and like other cephalopods they are bilaterally symmetric. An octopus has a hard beak, with its mouth at the center point of the arms...

.

Life cycle

Sexually mature individuals are hermaphrodites. They are broadcast spawners
Spawn (biology)
Spawn refers to the eggs and sperm released or deposited, usually into water, by aquatic animals. As a verb, spawn refers to the process of releasing the eggs and sperm, also called spawning...

. The season when the organisms spawn is variable between locations. However, in Tasman Bay
Tasman Bay
Tasman Bay is a large V-shaped bay at the north end of New Zealand's South Island. Located in the centre of the island's northern coast, it stretches along of coastline and is across at its widest point. It is an arm of the Tasman Sea, lying on the western approach to Cook Strait.At the bay's...

, the peak time is from November to March . Fertilisation occurs and a planktonic larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...

 forms. This life stage is conserved for approximately three weeks. Metamorphosis occurs and the larvae changes from planktonic to a benthic existence by attaching itself to suitable substrate
Substrate (marine biology)
Stream substrate is the material that rests at the bottom of a stream. There are several classification guides. One is:*Mud – silt and clay.*Sand – Particles between 0.06 and 2 mm in diameter.*Granule – Between 2 and 4 mm in diameter....

 on the seafloor. The attachment lasts until the individual is at least five millimetres long. The individual then detaches from the substrate and begins to grow into an adult. Maturity is usually achieved by 18 months.

Fisheries

The New Zealand scallop is a large industry and export
Export
The term export is derived from the conceptual meaning as to ship the goods and services out of the port of a country. The seller of such goods and services is referred to as an "exporter" who is based in the country of export whereas the overseas based buyer is referred to as an "importer"...

 product of New Zealand. The large white adductor muscle
Adductor muscle
- Humans :* Adductor muscles of the hip, the most common reference in humans, but may also refer to** Adductor brevis muscle, a muscle in the thigh situated immediately behind the pectineus and adductor longus...

 is eaten, sometimes the orange and white gonad
Gonad
The gonad is the organ that makes gametes. The gonads in males are the testes and the gonads in females are the ovaries. The product, gametes, are haploid germ cells. For example, spermatozoon and egg cells are gametes...

 is often eaten as well. P. novaezealandiae is considered a fine food and can be expensive to purchase. Recreational and commercial fishing of this species is allowed at particular times of the year, this is called scallop season. The size and number of scallops which can be caught are under control of the quota management system. In some areas of suitable habitat, such as Tasman Bay
Tasman Bay
Tasman Bay is a large V-shaped bay at the north end of New Zealand's South Island. Located in the centre of the island's northern coast, it stretches along of coastline and is across at its widest point. It is an arm of the Tasman Sea, lying on the western approach to Cook Strait.At the bay's...

, scallop spat is seeded. This is an attempt to achieve a sustainable fishery.

External links

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