Titre du document / Document title

Population structure, growth and recruitment of the euryalinid brittle-star Astrobrachion constrictum (Echinodermata: Ophiuroidea) in Doubtful Sound, Fiordland, New Zealand

Auteur(s) / Author(s)

STEWART B. G. ⁽¹⁾ ; MLADENOV P. V. ⁽¹⁾ ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

⁽¹⁾ Department of Marine Science, University of Otago, P.O. Box 56, Dunedin, NOUVELLE-ZELANDE

Résumé / Abstract

The euryalinid brittle-star (snake star) Astrobrachion constrictum (Farquhar) lives coiled around the branches of black coral (Antipathes fiordensis) colonies. Twenty-two vertical transects, 10 m wide by 30 m deep, were swum in Doubtful Sound over a 2.5 yr period from 1993 to 1995. Numbers, disc diameters and colour morphotypes of brittle-stars inhabiting coral colonies were recorded. 36.3% of the coral colonies >200 mm tall (n = 292) hosted ≥1 Astrobrachion constrictum (range 0 to 12). Overall, the population was patchily distributed on the available coral habitat. The dark red colour morphotype of A. constrictum was most common (87%, n = 279) followed by the yellow, striped, and then spotted varieties. The population was comprised mainly of large (≥10 mm disc diam) individuals, and juveniles were rarely encountered, indicating low rates of recruitment or a high mortality of recruits. Disc-diameter data gathered from this and previous studies indicated that growth in A. constrictum is initially rapid, with individuals reaching a disc diameter of 15 mm in ≃2.5 yr; growth decreases with age, as in other deep-sea ophiuroids. Growth rate within years, however, was not constant, with faster growth in the spring/summer. Maximum size for A. constrictum is reached in ≃8 yr at ∼23 mm disc diam. Anecdotal evidence indicates that A. constrictum may not be confined solely to black coral colonies.

Revue / Journal Title

Marine biology   ISSN 0025-3162   CODEN MBIOAJ 

Source / Source

1997, vol. 127, n^o4, pp. 687-697 (38 ref.)

Langue / Language

Anglais

Editeur / Publisher

Springer, Berlin, ALLEMAGNE  (1967) (Revue)

Mots-clés anglais / English Keywords

Population structure ; Growth rate ; Population recruitment ; Euryhalinity ; Coastal zone ; New Zealand ; Tasman Sea ; Oceania ; South Pacific ; Pacific Ocean ; Marine environment ; Echinodermata ; Invertebrata ;

Mots-clés français / French Keywords

Structure population ; Taux croissance ; Recrutement population ; Euryhalinité ; Zone côtière ; Nouvelle Zélande ; Mer de Tasmanie ; Astrobrachion constrictum ; Océanie ; Océan Pacifique Sud ; Océan Pacifique ; Milieu marin ; Echinodermata ; Invertebrata ;

Mots-clés espagnols / Spanish Keywords

Estructura población ; Tasa crecimiento ; Reclutamiento poblaciónal ; Eurihalinidad ; Zona costera ; Nueva Zelandia ; Mar de Tasmania ; Oceania ; Océano Pacífico Sur ; Océano Pacífico ; Medio marino ; Echinodermata ; Invertebrata ;

Localisation / Location

INIST-CNRS, Cote INIST : 8506, 35400006439898.0180