Aquaculture Research, 2007, 38, 1082 ^ 1087 d o i: 10.1111/ j.1365 -2109.20 07.01775. x Growth of the hatchery-produced juveniles of commercial sea cucumber Holothuria (Theelothuria) spinifera Theel P S Asha & P Muthiah Tuticorin Research Centre of Central Marine Fisheries Research Institute,Tuticorin,Tamil Nadu, India Correspondence: P S Asha, Tuticorin Research Centre of Central Marine Fisheries Research Institute, South Beach Road Extension, Tuticorin 628 001,Tamil Nadu, India. E-mail: [email protected] Abstract stocks in many countries have resulted in severe overexploitation of commercially important species. The present study was conducted to develop the Bruckner, Johnson and Field (2003) reported that the hatchery technology for seed production of the holothurians are susceptible to overexploitation be- widely exploited commercial sea cucumber Holothur- cause of late maturity, density-dependent reproduc- ia spinifera Theel 1886, to facilitate an e¡ective stock tion and low rate of recruitment. The release of enhancement programme. Broodstock collected by hatchery-produced juvenile sea cucumbers into the skin divers were used for spawning trials. The natural habitat is being advocated in many countries embryonic and larval stages were similar to other as one of the means of rebuilding the wild stock, a aspidochirotes. The larval survival rate was process termed as restoration, restocking or reseed- 43.5% on day 9, which decreased to 18.3% nearing ing (Battaglene1999). metamorphosis on day 13, the growth rate was The breeding and cultivation of holothurians dates 48 mmdayÀ1and the settlement rate was 3.5%. Alga- back to 1950, with the ¢rst recorded production of macs used to induce settlement also served as the juveniles of Stichopus japonicus (Imai, Inaba, Sato & food source for the early settled juveniles, followed Hatanaka1950). Later, studies on reproduction, early by Sargassum spp. extract (o40 mm) for the ¢rst development and metamorphosis of Cucumaria elon- month. Sargassum spp. powder along with ¢ne sand gata (Chia & Buchanan 1969), C. pseudocurata (1:1)was givento juveniles 420 mm. Addition of Spir- (Rutherford 1973), Aslia lefevrai (Costelloe 1988), Pso- ulina spp. along with Sargassum spp. powder and ¢ne lus chitonoides and P.bullatum (McEuen & Chia 1991) sand (0.5:1:2) enhanced the growth rate of the juve- and C. frondsa (Hamel & Mercier 1996) were exten- niles. In the hatchery, the juveniles attained an aver- sively undertaken. Meanwhile in 1985, techniques age size of 1, 30 and 48 on 20, 80 and 120 days were developed for producing juveniles of S. japonicus respectively. in China (Shuxu & Gongchao 1981; Chen 2003) and seed of Actinopyga echinites in Taiwan (Chen & Chian Keywords: Holothuria spinifera,survivalrate,Al- 1990). gamacs, Sargassum spp., Spirulina spp. Following the Chinese method, James, Rajapan- dian, Baskar and Gopinathan (1988) successfully pro- duced the seed of Holothuria scabra for the ¢rst time. Introduction This technique was later applied for the seed produc- Sea cucumbers belonging to the families Holothuri- tion of sea cucumbers in Australia, Indonesia, Mald- dae and Stichopodidae form an important part of ives and Solomon Islands (Battaglene 1999). The multispecies ¢shery, existing for over 1000 years seeds of Isostichopus £uscus and H. fuscogliva have along the Indo-Paci¢c region, and the processed pro- been successfully produced in Ecuador and in Kirbati duct is a valuable source of income. Increasing de- Island (Hamel, Hidalgo & Mercier 2003; Friedman & mand and inadequate management of sea cucumber Tekanene 2005). r 2007 The Authors 1082 Journal Compilation r 2007 Blackwell Publishing Ltd Aquaculture Research, 2007, 38, 1082^1087 Hatchery-produced juveniles of commercial sea cucumber P S Asha & P Muthiah In India, the beche de-mer industry mainly de- For holothurian seed production150 000 fertilized pends on two species, H. scabra and H. spinifera (Chel- eggs, 5700 pentactulae and 2000 juveniles were laram, Samuel & Patterson Edward 2003), and both reared in a lot following the hatchery technique the species are being processed for export. Holothuria (James et al.1988; Battaglene1999; Chen 2003).While spinifera, locally called cheena attai or raja attai, was rearing, periodically representative samples were once rated very high in the market and was in good measured for assessing the growth of larvae and ju- demand in China. At present, the market value is veniles. The microalgae cultured by the serial dilu- moderate; the processed ones (60 counts kg À1) fetch tion technique (Gopinathan 1982) were provided as US $37.5. Besides Gulf of Mannar and Palk Bay of In- larval feed as indicated in Asha and Muthiah (2006) dian coast, this species is reported to occur in the Red and at a concentration speci¢ed byAsha (2004). sea, Persian Gulf, Sri Lanka, North Australia, Philip- The doliolaria larvae on10th day were maintained pines and China (James 1995). James and Badrudeen in a £owthrough system, in which an equal volume of (1997) reported an estimated annual landing of 460 seawater released was let in and were provided with tonnes of fresh H. spinifera along the south-east coast Algamacs (Bio-Marine, Hawthrone, CA, USA) at a of India. Increase in demand and inadequate ¢shery rate of 0.5 g 500 L À1 for inducing them to settle as management has resulted in overexploitation of com- pentactulae.TheAlgamacs was provided for13 days mercial sea cucumber species in India also; hence, until the juveniles became visible to the naked eye. the Ministry of Environment, Government of India, For the newly settled juveniles, Sargassum spp. ex- has banned both ¢sheryand export of sea cucumbers tracts (o40 mm) were given (10L 500 L À1)for4 since 2001, which has had a severe impact on the li- weeks.When the juveniles attained an average length velihood of poor coastal communities subsisting on of 20 mm, a mixture of Sargassum spp. powder and its ¢shery and processing. Owing to the role played ¢ne sand in a proportion of (1:2) was given at 1% of by H. spinifera in the commercial ¢shery and also the body weight of juveniles (initially o80; due to its indiscriminate exploitation, knowledge of o200 mm as the days progressed). From day 30, Spir- early development, larval and juvenile rearing is es- ulina spp. (15mg juvenile À1) was provided along sential for the seed production so as to carry out, the with the above feed. Every week, juveniles were taken captive or wild stock enhancement programme of out using a ¢ne brush and the length and number of this species e¡ectively. Hence, an attempt was made live juveniles were noted for assessing the growth to produce juveniles of H. spinifera in the laboratory. and survival rate. Once in a week, the juveniles were The present work is the ¢rst successful attempt of ju- transferred to another tank as suggested by Batta- venile production of this species under laboratory glene (1999). The juveniles thus produced from ferti- conditions. lized eggs were reared up to120 days. Materials and methods Results and discussion The broodstock of H. spinifera collected by skin divers Spawning and development were maintained in 1000L FRP tanks having 150 mm thickness of ¢ne coral beach sand at the bot- The induced spawning on 2 January 2003 occurred tom. The water was exchanged daily and sand every in the afternoon, after addition of feed. There was no fortnight and the brooders were fed with Sargassum spawning by thermal stimulation. The female spp. powderat the rate of 5% of their body weight. spawned ¢rst, followed by three males. For induced spawning, among the 30 numbers of The spawning in H. spinifera was induced by addi- broodstock, 10 numbers were subjected to thermal tion of feed. Addition of Algamacs at 50 g 500 L À1 stimulation wherein the holothurians were exposed induced spawning in H. fuscogilva (Battaglene, Sey- to 3^4 1C above the ambient temperature for an hour. mour & Ramofa¢a 2002). Thermal stress, despite The high temperature was maintained by a heating having been e¡ective for S. japonicus (Ishida 1979), element controlled by a thermostat. Similarly, indu- H. scabra (James et al. 1988) and H. scabra and A. maur- cement by addition of feed constituted by rice bran, itiana (Battaglene et al. 2002), did not induce H. spini- Soya powder and Sargassum spp. powder (4:1:2) at a fera to spawn. Similarly, Battaglene et al.(2002) rate of 50 g 500 L À l was also attempted to 10 num- observed that thermal stress was not e¡ective but ad- bers and the remaining10numbers were maintained dition of dried algae alone yielded induced spawning as control. in H. fuscogilva. r 2007 The Authors Journal Compilation r 2007 Blackwell Publishing Ltd, Aquaculture Research, 38, 1082 ^ 1087 1083 Hatchery-produced juveniles of commercial sea cucumber P S Asha & P Muthiah Aquaculture Research, 2007, 38, 1082 ^ 1087 In the successful spawning experiment, the fe- by 20% for periphytic diatom-fed larvae. Ito and males spawned ¢rst, followed by the males. Because Kitamura (1997) accelerated the metamorphosis in the released gonadal materials instigate the mass S. japonicus by providing periphytic diatom at spawning, the blended gonad from mature brood- 420 000 cells cm À 2. Studies have to be undertaken stock may be an e¡ective spawning stimulant (Batta- to evolve suitable cues and their concentration so as glene 1999). to obtain more juveniles. The spawning behaviour of H. spinifera and the On day 15, 5700 pentactulae of 0.32 mm length, occurrence of spawning in the afternoon were simi- forming 9.4% of early auricularia, were produced. lar to the observations on other aspidochirotids On day 23, 2000 juveniles of 0.95mm, forming 3.5% (McEuen 1988). The spawning in the late afternoon of early auricularia, were reared. On day 31, the juve- and evening may be related to a decrease in light in- niles had a mean length of 2.3 mm (Fig.