Sinclair, Mary. (1963). Studies on the Paua, Haliotis iris Martyn in the Wellington district, 1945-46. Zoology Publications from Victoria University of Wellington. 35: 1-16.

416204

Sinclair, Mary

1963

35: 1-16

Publication

https://nzetc.victoria.ac.nz/tm/scholarly/tei-Vic35Zool.html

World Polychaeta Database (WPolyD).

A brief historical survey is given of the use to which shell and soft parts of the animal were put by the Maori, and the economic importance of the shell and soft parts _in New Zealand at the present time; also the figures for the number of specrmens removed from Cook Strait area over a two-year period by one fisherman. Indications of the areas from which good and bad shells can be obtained are given.. Haliotis australis is almost without exception found in connection with H. iris but in very small proportions. No H. virginea were found in the Cook Strait area although they are known to occur further south. H. iris is considered to have a homing instinct in its nocturnal movements but no indication was found that it undergoes winter migration to deeper water. The shell of H. iris is unique in having a brilliant iridescence when polished due, probably, to dark conchiolin lines alternating regularly with nacreous material so that nowhere is there any great thickness of nacre. Conchiolin deposition commences. when the shell is approximately 5cm in length and the deposition of conchiolin and nacre can be carried out by all parts of the mantle in contact with the shell. A section of diseased mantle shows numerous dark brown granules scattered throughout the epithelial cells, connective tissue and muscle. It was not possible to determine the exact nature of these granules. The relation of length to age for young shells was determined by graphing a number of shells from two areas and it was estimated that shells 1.9 cm to 2.9 cm and 2.9 to 3.8 cm. were in their second and third years of growth. An attempt was made to estimate the age of older shells from the number of conchiolin growth lines counted on longitudinally sectioned shells. The only conclusion able to be reached regarding these lines was that they are regularly laid down in response to some physiological need. The time interval which each line represents was not able to be determined. A close correlation was found between the number of perforations present in small shells and the length of the shell. The number of perforations increased regularly with the length of the shell. The average number of open perforations was five in H. iris. The growth relation for H. iris in Cook Strait area was found to be 75. 7 which is wider than in H. tuberculata (Crofts) and H. gigantea (Sasaki). H. australis gives a ratio close to H. iris, namely 70.0. The constant angle of the logarithmic spiral in H. iris was determined as 53 degrees 46' in a specimen 9.9cm in length. No specimens of H. iris or H. australz.s were observed with macroscopic disease of the soft parts, but all shells over approximately 5cm in length had some encrustmg calcareous algal growth and all shells over 10cm in length had tube worms on the outer surface. Heavy infestation of tube worm sometimes led to large tubercles forming inside the shell but the most common cause of tubercle formation was considered to be irritation by sand grains. The commonest species of annelid worm present was Polydora. Other forms identified were Nereis sp, Polycirrus sp., Hydroides sp, and Thelepus sp. H. iris feeds on a variety of seaweeds and diatoms. In the small specimens the gut contents show a predominance of red seaweeds while brown seaweeds are most common in the larger specimens. The ratio of male to female specimens in H. iris is 1.43 for a count of 352 specimens taken in the winter months.

New Zealand

Biology

Annelida
Mollusca
Polychaeta

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