Spawning and rearing ofHolothuria tubulosa: A new candidate for aquaculture in the Mediterranean region

Abstract

Holothuria tubulosa (Gmelin, 1788) has recently shown an increased demand in Asian markets, becoming one of the intensively exploited holothurian species in the Mediterranean Sea. A risk is that over-harvesting is likely affecting both the species' natural stocks and the benthic communities. In this scenario, sea ranching and restocking through aquaculture could assist in mitigating its overexploitation. This study is the first to demonstrate the successful artificial breeding and rearing of H. tubulosa, and its consequent potential as a new species for the Mediterranean aquaculture industry. Here we describe the spawning induction, larval development and early juvenile growth in hatchery cultures, aimed at developing a spawning and rearing protocol for this species. The trials were conducted from July to October in both 2014 and 2015. Holothuria tubulosa was induced to spawn by testing four different methods. Thermal stimulation plus thermal shock emerged as the most efficient method to obtain active and healthy gametes. Larval development in H. tubulosa progressed through five stages, reaching the juvenile stage in 27 days.Two different microalgal feeding regimens were tested for larval breeding. Under the best feeding conditions, 7% of the larvae metamorphosed into settled juveniles, adhering to artificial substrates previously conditioned with benthic biofilm. Our results indicate that H. tubulosa shows good performance in hatchery rearing during the larval phases, indicating that this species could be a new candidate for aquaculture in the Mediterranean region, both for production and restocking proposes. K E Y W O R D SHolothuria tubulosa, larval feeding, larval rearing, mariculture, sea cucumber, spawning

Breeding and larval development ofHolothuria mammata, a new target species for aquaculture

“…H. mammata was induced to spawn by thermal stimulation, being this methodology largely used in many other different tropical and temperate species, e.g. A. mauritiana, Athyonidium chilensis, A. mollis, Bohadschia marmorata, Holothuria atra, H. fuscogilva, H. tubulosa, H. scabra, and I. badionotus (Battaglene, Seymour, & Ramofafia, ; Battaglene, Seymour, Ramofafia, & Lane 2002; Dabbagh & Sedaghat, ; Eeckhaut, Lavitra, Léonet, Jangoux, & Rasolofonirina, ; Guisado, Carrasco, Díaz‐Guisado, Maltrain, & Rojas, ; Ivy & Giraspy, ; James, Rajapandian, Baskar, & Gopinathan, ; Kumara & Dissanayake, ; Kumara, Jayanatha, Pushpakumara, Bandara, & Dissanayake, ; Laxminarayana, ; Mercier, Battaglene, & Hamel, ; Morgan, ; Rakaj et al., ; Ramofafia, Byrne, & Battaglene 2003; Zacarías‐Soto et al., ). This method was also recently applied to induce the spawning to H. arguinensis (Domínguez‐Godino et al., ), species inhabiting with H. mammata the Portuguese waters.…”

“…Holothuria mammata larvae were reared at 1 larvae/ml, the same density used on H. arguinensis (Domínguez‐Godino et al., ), H. scabra (Battaglene & Bell, ), H. tubulosa (Rakaj et al., ) and I. badionotus (Zacarías‐Soto et al., ). H. mammata larvae showed 20% of mortality in the first day after the early auricularia stage was reached.…”

“…Settlement and juveniles’ stages are critical periods for sea cucumbers. In fact, high mortality on these stages has been observed for species such A. mollis (Morgan, ), Cucumaria frondosa (Hamel & Mercier, ), H. arguinensis (Domínguez‐Godino et al., ) H. scabra versicolor (Ivy & Giraspy, ; Kumara et al., ), H. scabra (Battaglene et al., ; Ramofafia et al, ), H. spinifera (Asha & Muthiah, ), H. tubulosa (Rakaj et al., ) and I. badionotus (Zacarías‐Soto et al., ).…”

“…The feeding protocol established to feed H. mammata was similar to that used to feed H. arguinensis (20,000–40,000 cells/ml) under similar larvae rearing and feeding protocol. However, H. mammata might require different microalgae concentration, such as H. tubulosa (Rakaj et al., ) and A. mollis (Morgan, , ), species that showed optimal growth and development at 5,000–10,000 cell/ml. This factor could have caused the decreased of larvae survival along the pelagic stages and the low settlement rate.…”

Improving the fitness of Holothuria arguinensis larvae through different microalgae diets

“…Holothuria scabra is the second largely produced sea cucumber species in aquaculture with a current production of 130 tons/year (Robinson & Lovatelli, ). However, many other sea cucumbers, such as Actinopyga miliaris , A. mauritiana , Australostichopus mollis , H. fuscogilva , H. mammata , H. spinifera , H. tubulosa , Isostichopus badionotus , I. fuscus , Parastichopus californicus and Stichopus horrens , are target species for aquaculture development around the world, though most of them are in their early stage (Domínguez‐Godino & González‐Wangüemert, ; Purcell, Hair & Mills, ; Rakaj et al., ; Zacarías‐Soto, Olvera‐Novoa, Pensamiento‐Villarauz & Sánchez‐Tapia, ).…”