Aspects of the ecology ofStichopus mollis(Echinodermata: Holothuroidea) in north‐eastern New Zealand

Abstract

The size-frequency distribution, sex ratio, and visceral index in a population of the aspidochirote holothurian Stichopus mollis (Hutton, 1872) were studied on the north-east coast of New Zealand. Adult Stichopus mollis ranged in length from 13 to 25 cm, and showed a unimodal sizefrequency distribution. Young S. mollis were rare, and were found under boulders in the shallow subtidal zone (5-8 m). The population of S. mollis under study showed a 1 : 1 sex ratio; three hermaphrodites were found. The viscera index maintained an approximately uniform value throughout the reproductive season. No evidence was found for spontaneous evisceration or seasonal atrophy of the viscera. Two predatory attacks on S. mollis by the asteroid Luidia varia were observed.

Patterns of distribution and abundance of the temperate sea cucumberAustralostichopus mollison a rocky subtidal reef

“…Locations consisted of headland outcrop areas where abundance of A. mollis was high, to coastal areas and inner bays where less occurred. Abundance of A. mollis was also highest in areas previously examined (Sewell 1990). These areas consisted of boulders and cobbles mixed with areas of the algae Caropphyllum flexuosum and some Ecklonia radiata (Sewell 1990).…”

“…A. mollis can be found on coarse sand and mud in sheltered regions from low tide to 1530 m depth in Milford Sound, Southern-Western New Zealand (Dawbin 1949). It is also found in large numbers in the subtidal zone, low tide to 12 m depth, on sheltered and exposed rocky reefs and coastal areas of north eastern New Zealand (Sewell 1990;Sewell & Bergquist 1990;Archer 1996). Australostichopus mollis is typically 13Á25 cm in length and often has a unimodal size-frequency distribution.…”

“…Limited quantitative information exists on the role of rocky reef structure in determining patterns of distribution and abundance of the New Zealand aspidochirote deposit feeding sea cucumber Australostichopus mollis (Hutton, 1872) (Holothuriidae) (Sewell 1990;Mladenov & Campbell 1996;Shears & Babcock 2007), which was formally known as Stichopus mollis (Moraes et al 2004). Within these subtidal rocky reefs, topographic features exposed and acted on by erosion can be used to describe the relationship between a reef and inhabitants such as sea cucumbers.…”

“…Australostichopus mollis is typically 13Á25 cm in length and often has a unimodal size-frequency distribution. The ecology of A. mollis is little understood and limited to a few publications (Dawbin 1949;Sewell 1990;Archer 1996;Mladenov & Campbell 1996, Raj 1998. Its production, biology and feeding ecology has been studied in detail (Slater & Carton 2007;Morgan 2008Morgan , 2009StentonDozey & Heath 2009;.…”

“…Previously, temperate reef systems have been classified according to community composition of flora and fauna, depth and exposure gradients (Ayling 1978;Choat & Schiel 1982;Taylor 1998). Classification of this topographic complexity by recording changes in the proportional composition of physical features should relate directly to the often patchy distribution and abundance of sea cucumbers such as A. mollis (Sewell 1990;Shears and Babcock 2007).…”