Despite the important ecological roles of commercial bêche-de-mer holothuroids in coral reef ecosystems their reproductive biology is poorly studied, including on the Great Barrier Reef (GBR). We investigated reproduction of Stichopus herrmanni, a commercially important species listed as Vulnerable, at One Tree Island, southern GBR. Gonad index, histology and spawning observations indicated an annual reproductive cycle with gamete release in the Austral spring and summer (November–February), as for populations of this species at a similar latitude in New Caledonia. Stichopus herrmanni releases gametes episodically, spawning multiple times during summer. Assimilation of spawning observations from OTI and elsewhere along the GBR and tropical Pacific revealed that gamete release by S. herrmanni is influenced by the lunar cycle, with spawning taking place around the new moon in summer. This species is an aggregative spawner with a behavioural change to attain elevated positions on the reef at dusk prior to spawning. After the spawning season, gametes remaining in the gonads are reabsorbed. Spent gonads completely lacked gametes. There was a quiescence in gonad development in winter with an absence of gonads in some specimens, indicating an aestivation-like period for reproduction. By late-winter (August) recovery stage gonads were distinguished by the initiation of gametogenesis, which coincided with increasing temperature and day length. Our findings contribute to the understanding of the reproductive biology of S. herrmanni, a consideration for future fisheries management in the protection of this Vulnerable species, especially with respect to the increasing global trade in bêche-de-mer.

Albinism is a hereditary lack of pigmentation caused by deficiencies in enzymes related to the metabolism of melanin. This mutation is present in marine vertebrates and invertebrates, including the Holothuroidea class; nevertheless, information about the occurrence of albinism in these kinds of echinoderms is scarce and refers to species from temperate and cold regions of the ocean. In 2013, we observed two albino individuals of Isostichopus fuscus, one at Loreto (25°45′54″N, 111°14′36″W) and the second one at Los Angeles Bay (29°02′54″N, 113°29′49″W). This is the first documented record of albinism for this species.

Population density and the presence of fission products of Holothuria (Halodeima) atra were investigated in surveys taken over 5 years (2006–2010) in the Capricorn Bunker Group, Southern Great Barrier Reef. These surveys were undertaken to document population density over time and assess the potential that asexual reproduction contributes to population maintenance. Over the 5 years a low incidence of fission was evident year-round, with an increase in July and August (13 and 27% of the population, respectively). There was a positive correlation between population density and the presence of fission products across all surveys. Although density fluctuated, there was no significant difference between months or sites. Despite the potential increase that might be expected from fission followed by regeneration, density fluctuated around a mean of 0.77 ind. m−2. Examination of gonads of the small (asexual and sexual reproduction) and large (sexual only) morphs of H. atra indicated a difference in reproductive pattern. Many small morphs lacked gonads during winter and, when they developed gonads, the gonad index (GI) was low. The GI pattern of the small morph indicated that they spawned in summer. In comparison the large morph had conspicuous gonads through the year. The GI of the large morph was high in winter and summer indicating greater, more prolonged spawning activity in these individuals.

The order Tanaidacea includes over 1000 species which are mainly free-living or tube-dwelling detritivores. Exspina typica Lang, 1968 represents an exception to these common life styles, having being found in the intestine and body cavity of deep sea holothuroids. The 2008 New Zealand ‘IPY-CAML Cruise’ held in the Ross Sea collected several deepwater holothuroids that were observed to carry specimens of E. typica inside their coelomic cavity. A clear interpretation of this association was hence possible. Even if E. typica shows slight adaptations to a parasitic life style, the tanaids were found to actively ‘dig’ into the host's skin, grasping tissue with their claws and producing tunnels in the body wall. It is therefore possible to clearly define this association, which is here reported from the Antarctic for the first time, as parasitism.

We describe a new association for Antarctica, involving an holothuroid host, Bathyplotes bongraini Vaney, 1914, and a parasitic polynoid polychaete, Eunoe opalina McIntosh, 1885, which lives on the host body. Both species have never been recorded in the study area, the Ross Sea. The ecological definition of this partnership is difficult to assess, being a mix of phoresis, protective association, parasitism and, possibly, kleptocommensalism. Eunoe opalina emerges also as a true predator, ingesting several food items that do not belong to the diet of Bathyplotes. We compare this association with analogous examples known from shallow tropical environments as well as bathyal and abyssal depths. Given the conspicuous similarities between the deep water and high latitude examples of this kind of association, a possible common origin is hypothesized. Although the role of such a kind of parasitic relationships in Antarctic communities remains to be fully evaluated, it seems evident that, at high latitudes, where trophic levels are simplified and food webs do not have much redundancy, the impact of such a ‘multitasking’ predator-parasite as E. opalina might be of a greater magnitude than its shallow water tropical counterpart.

A new species of a dendrochirotid holothuroid, Thyone herberti, is described from the deep waters of Matigulu, KwaZulu-Natal, South Africa. The new species is distinct from other species of the genus in the form of its calcareous ring, in which the radial plates are prolonged posteriorly before bifurcating, and in the presence of non-rosette-like perforated rods and plates in the tentacles and the introvert. The new species increases to eight the number of southern African species currently classified in the genus Thyone.

One new genus and three new species of deep-sea holothuroids, taken by the South African Division of Sea Fisheries R.S. Africana II routine trawls, off the west coast of the Cape Peninsula in South Africa in 1959, are described. A new genus Psolidothuria, perhaps referable to the dactylochirotid family Vaneyellidae, is erected for the new species P. octodactyla. The remaining new species are Paracucumaria capense, in the dendrochirotid family Cucumariidae, and Laetmogone perplexa, in the elasipodid family Laetmogonidae. P. capense was originally described as Trachythyone ?parva (Ludwig) by Thandar (1991). The diagnosis of the family Vaneyellidae is amended to accommodate the new genus.