Southward transplanted cage-culture of sea cucumbers Apostichopus japonicus in China s Shengsi Islands

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1 33 SPC Beche-de-mer Informtion Bulletin #32 Mrch 2012 Southwrd trnsplnted cge-culture of se cucumbers Apostichopus jponicus in Chin s Shengsi Islnds Abstrct Kun Xing, 1, 2, 3 Shilin Liu, 1 Hongsheng Yng, 1,* Mingzhu Zhng, 1 Yi Zhou 1 Three sizes of the se cucumber Apostichopus jponicus were cultured in blone cges, nd survivl nd growth were monitored semi-monthly or monthly, from December 2007 to My 2008, using fermented seweed s feed. The se cucumbers in four sites hd high survivorship ( 83%). Growth of lrge individuls (~70 g men live weight) ws slow when densities reched pproximtely 5 ind. lyer -1. Growth rtes were negtively correlted with culture densities; for lrge juveniles t high densities, growth rtes were the sme s those for medium sized juveniles (bout 30 g men live weight) nd smll juveniles (50 g men live weight) tht were not stunted t high densities. Juveniles of ll three sizes grew progressively except fter April when se tempertures incresed. A. jponicus with body weight of 40 g nd in densities of 3 5 ind. lyer -1 cn be frmed successfully in blone cges. Trnslting cges to more southerly (i.e. wrmer) sites cn extend the growing period of se cucumbers, llowing them to rech commercil size over the course of the yer. Nturlly occurring popultions of A. jponicus in the northern end of the Est Chin Se hve low growth rte during winter. Field-bsed growth trils for the purpose of culturing A. jponicus in the Shengsi Islnds (southern Chin) were crried out. Introduction Se cucumbers, especilly Apostichopus jponicus, re mong the most economiclly importnt nd commercilly exploited orgnisms in Chin due to their high qulity met nd the successful techniques used in commercil htcheries (Lio 1997). Se cucumbers hve been successfully bred to provide lrge numbers of juveniles (Sui 1988; Ito 1995), which holds gret promise for restocking, stock enhncement, nd se rnching progrmmes. A. jponicus is found in Russi, northern Chin, Jpn, nd North nd South Kore (Slon 1984). Se rnching of se cucumbers ws initited in Jpn in the lte 1930s nd by the Yellow Se Fisheries Reserch Institute in Chin in 1980 (Sui 1988), nd ws lso developed more recently in the Pcific Islnds (Bttglene nd Bell 2004). In recent yers, mny se cucumber frming techniques hve been developed, such s frming in shrimp ponds, in offshore ponds, nd in cofferdms filled by grvity-fed sewter (Chen 2003). Currently, in north Chin, A. jponicus is minly frmed in nershore wters in depths less thn 15 m, which re often polluted problem tht reduces the number of suitble res for frming. The extension of frming res to deep wter nd to southern Chin would provide more fvourble environmentl conditions nd reduce the stress induced by frming in costl res. The culture of htchery-bred juveniles in southern Chin could reduce the time required to rech hrvest size. Xio nd Gu (1981) trnsplnted dult nd juvenile se cucumbers in Ximen, southern Chin for culture nd spwning experiments. Sun et l. (2006) lso trnsplnted juvenile se cucumbers in Nnji Islnd (27 27 N, E) in southern Chin; the results showed tht the se cucumber grew well. Juvenile se cucumbers were bred rtificilly nd cted normlly, with good conditions nd high survivl rtes even fter estivtion from erly June to the middle of November, which lsted for 160 dys in the summer. In northern Chin, sewter tempertures in winter drop below 5 C, which constrins the growth nd survivl of se cucumbers. Cge-culturing se cucumbers in southern Chin s wrmer wters would provide mny dditionl potentil frming res, reduce growth time before hrvest, nd mke it possible to frm se cucumbers in the winter months. The Shengsi Islnds (30 72 N, E) in southern Chin comprise some 200 islnds with long history of mrine quculture. However, rubble nd rocky substrtes needed for se cucumber frming re scrce in the Shengsi Islnds, where most substrtes consist of snd nd mud bottoms t depths tht rnge between 5 m nd 20 m. Se cucumber 1 Chin Acdemy of Mrine Ecology nd Environment Science Lbortory. Emil: xingkun84@gmil.com 2 Grdute School, Chinese Acdemy of Sciences, Beijing, PR Chin 3 Dlin Ocen University, Dlin, PR Chin * Corresponding uthor. Tel./fx: Emil: hshyng@ms.qdio.c.cn

2 34 SPC Beche-de-mer Informtion Bulletin #32 Mrch 2012 hbitt could be rtificilly simulted by dding hrd substrt, lthough the cost would be high. Furthermore, light penetrtion decreses with depth, thereby constrining the growth of seweed, which is used s cover nd food for se cucumbers. In ddition, the nylon-mesh enclosures of scllop suspended-culture results usully in ulcers nd deth of se cucumbers. By contrst, blone cges suspended from rfts used by frming fcilities re esily ccessed. There hs been n incresing interest in the possibility of culturing deposit-feeding se cucumbers tht would consume sediments from the cges or pens used in scllop frming, thereby reducing the negtive effects of scllop culture on the benthic environment nd potentilly producing vluble secondry product. A previous study showed tht A. jponicus grew well nd reduced orgnic wstes when polycultured with scllops in lntern nets in northern Chin (Zhou et l. 2006). Pltzt et l. (2008) used oyster grow-out trys, which were designed to collect biodeposits nd prevent se cucumber escpe, for the production of Prstichopus clifornicus Stimpson. Deposit-feeding holothurins ingest sediment bering orgnic mtter, including bcteri, protozo, ditoms, nd detritus of plnts nd nimls (Yingst 1976; Morirty 1982; Zhng et l. 1995). In recent yers, fermented seweed, especilly Lminri jponic Aresch nd Ulv pinntifid hve been used s food sources of cultured se cucumbers in Chin (Sui 1988). Fermented seweed mixed with debris such s mud, ded lge, nd se cucumber feces tht settle on the inside of the cges cn provide the min orgnic nutrient resource for se cucumbers. Those se cucumbers tht were fed with fermented seweed or mixed diets grew well, indicting tht fermented seweed could be n idel food for se cucumbers (Yun et l. 2006). Only if juvenile se cucumbers survive to commercil size will culturing them dd vlue to locl economies. This study determined growth nd survivl of the se cucumber A. jponicus during southwrd trnsplnttion in the Shengsi Islnds in southern Chin. Se cucumbers were in blone cges with fermented seweed s feed to test the fesibility of se cucumber culture in southern Chin. Mterils nd methods Animl mterils Se cucumbers were obtined from htchery lrve produced in Mrch 2007 in Ynti, Shndong Province in northern Chin. The men size of se cucumbers t the strt of the experiment ws ± g (n = 330). Body weight ws mesured while juvenile se cucumbers were fully extended. Se cucumbers were then pcked into insulted boxes nd trnsported by ir to the frm within six hours. All nimls were cclimtised in 10-m 3 lnd-bsed, concrete tnk with composite snd nd nturl light for t lest one week before the experiments. Study sites Shnghi The study ws conducted from December 2007 to My 2008, in the re est of Shengsi Islnd in Zhejing Province, in the Est Chin Se. The study res were shielded by the mussel frming re in depths of 5 20 m. Sewter ws clen with no obvious pollution. Tides nd currents in this re re gentle nd stedy. Four sites were chosen for culturing juvenile se cucumbers: two t Gouqi Islnd (G1: E, N nd G2: E, N), one t Hunio Islnd (HI: E, N), nd one t Shenshn Islnd (SI: E, N) (Fig. 1). Environmentl conditions Shengsi Islnds G1, G2 Figure 1. Loctions of Apostichopus jponicus culture. G1, G 2: Gouqi Islnd (sites 1 nd 2); HI: Hunio Islnd; SI: Shenshn Islnd. Sewter tempertures rnged from 7.5 C in Februry 2008 to 17.2 C in December 2007 (Fig. 2), which is within the optiml temperture rnge (10 17 C) for A. jponicus growth. Wter trnsprency ws round 2 m. The sewter ws well mixed nd remined sturted with dissolved oxygen. ph vlues were nd slinities were ppt. SI H1

3 Wet weight (g) Dec 5 Jn 1 Mr 30 Mr 15 Apr 14 My Figure 2. Sewter temperture nd men growth of lrge, medium nd smll Apostichopus jponicus t site G1. Brs represent stndrd errors (n = 20). Culture fcility Six-lyered blone culture cges (0.4 m length 0.3 m width 0.8 m height, 1,250 cm 2 lyer -1 ) (Fig. 3) were used for the experiments. For ech lyer of the rigid plstic cges, six perpendiculr substrtes of 10 cm width were plced inside to provide se cucumbers with extr hbitble re nd to trp sediment. Ech underside ws intct without impcting surrounding lyers. A door ws included on ech cge for feeding nd ccess. The cges were nchored to the longlines of rft fixed on the sndy se bottom, nd suspended in depths of 3 6 m. Experimentl design Sewter temperture Lrge se cucumbers 20 Medium se cucumbers Smll se cucumbers 18 Smpling time Three sizes of se cucumbers were plced in density of 6 ind. lyer -1 in fixed blone cges t ech site. Densities of lrge individuls were 3, 5, nd 7 ind. lyer -1 ; densities of medium sized individuls were 4, 6, nd 8 ind. lyer -1 ; nd densities of smll individuls were 6, 8, nd 10 ind. lyer -1. Initil wet SPC Beche-de-mer Informtion Bulletin #32 Mrch 2012 Temperture ( C) 35 weights (men ± stndrd error) were ± g for lrge se cucumbers (n = 90), ± 4.90 g (n = 109) for medium sized se cucumbers, nd ± 5.43 g (n = 131) for smll se cucumbers in G1. Tretments were monitored fortnightly or monthly for six months. Fermented seweed, Lminri jponic Aresch, nd Undri pinntifid, were ground nd plced in blone cges twice week; the weight of the seweed equlled the wet weight of the se cucumbers. About 13,500 kg of juvenile se cucumbers of individul weights of t lest 40 g were plced in the four sites; site SI hd the gretest number of juveniles (7,500 kg). Mintennce of culture re nd mesurement of survivl nd growth During the experiments, survivl nd growth were quntified by counting nd weighing juvenile A. jponicus in ech cge nd t ll study sites. All se cucumbers were mesured every 15 or 30 dys nd then plced bck in their respective lyer within ech cge until the next smpling period. Survivl ws recorded s the presence or bsence of individul se cucumbers in the ssigned cge. Body weight ws mesured while ech juvenile se cucumber ws fully extended. Temperture, slinity, ph, nd fouling were monitored every one to three dys. Longlines, flots, nd cges were inspected every dy. Ablone cges were clened to remove the fouling orgnisms every week. The specific growth rte (SGR) nd growth rte (GR) were clculted s follows: SGR (% d -1 ) =100 (lnw 2 lnw 1 ) T -1 ; GR (mg d -1 ) = 1000 (W 2 W 1 ) T -1 ; Figure 3. Single cge used for culturing Aposticopus jponicus in the present study (0.4 m length 0.3 m width 0.8 height, 1,250 cm 2 lyer -1 ) nd ssembled six-lyer cge. Note cultured A. jponicus (rrow) lid in blone cge.

4 36 SPC Beche-de-mer Informtion Bulletin #32 Mrch 2012 Where W 1 is the previous wet weight (g) nd W 2 is the current smpling wet weight (g) of the se cucumber. Temperture ws recorded throughout the experiments. Dt nlysis Sttistics were performed using SPSS 11.0 softwre. A two-fctor nlysis of vrince (ANOVA) with cultured density within the size ws used to determine ny significnt differences in survivl nd growth of juvenile A. jponicus cultured in different hbitts. Dt re presented s mens ± stndrd error of the men (SE). We nlysed the growth of se cucumbers t three different densities in G1, nd compred the difference between SGR nd GR for ech size t ech different density t ll four sites. Dt were tested for homogeneity of vrinces with Cochrn s tests; ll dt were suitble for nlysis without trnsformtion. One-wy ANOVA, followed by Duncn s multiple rng tests, were used to test the differences mong tretments. Differences mong smpling dtes were considered significnt (P <0.05). Results Se cucumber survivl Overll, survivl t ll study sites ws high throughout the experiments, reching s high s 100% for lrge juveniles, 93% for medium sized juveniles, nd 83% for smll juveniles. Size nd survivl of juvenile se cucumbers were positively correlted. Specific growth rte (%) Specific growth rte (%) Specific growth rte (%) (0.0020) Jn 5 Jn 5 Jn Dte Figure 4. Specific growth rtes of lrge (A), medium (B) nd smll (C) Aposticopus jponicus during six-month growth experiment est of Shengsi Islnd, southern Chin. Mens with different letters indicte significnt differences (P <0.05), nd brs represent stndrd errors of the mens (n = 4 sites). 1 Mr 1 Apr 15 Apr 14 My 1 Mr 1 Apr 15 Apr 14 My 1 Mr 1 Apr 15 My b A B C Effect of size on specific growth rtes of A. jponicus At G1, initil wet weight (men ± SE) of smll A. jponicus ± 5.43 g ind -1 incresed to ± 7.95 g ind -1 fter six months (Fig. 2). Medium sized A. jponicus of ± 4.90 g ind -1 initil weight grew to ± g ind -1, nd lrge A. jponicus of ± g ind -1 initil weight grew to ± g ind -1. SGR of juvenile se cucumbers of ll sizes nd times showed progressive growth, except tht the lowest SGR occurred in My for lrge juvenile se cucumbers (Fig. 4A), perhps becuse temperture incresed. Differences in SGR were not significnt for smll nd medium sized se cucumbers (Figs. 4B nd 4C) s determined by one-wy ANOVA (P <0.05).

5 Effect of culturing density on growth rtes of A. jponicus The GR t different densities nd times ws vrible nd density-dependent (Fig. 5) s determined by Duncn multiple comprison test. There ws negtive correltion between GR nd culturing densities (p <0.05), for exmple, bsolute dily growth rtes for lrge juvenile se cucumbers frmed t different densities verged 0.18 ± 0.10 g d -1 t density of 3 ind. lyer -1 over the whole experiment, which ws not significntly different from GRs of 0.13 ± 0.04 g d -1 t density of 5 ind. lyer -1, or 0.09 ± 0.06 g d -1 t density of 7 ind. lyer -1. Dily GRs decresed with incresing densities of se cucumbers. Discussion Growth rte (mg d-1) This study employed cging method tht would be prcticl for the commercil culturing of the se cucumber A. jponicus in southern Chin. Other experiments with A. jponicus culture in southern Chin were minly restricted to htcheries nd ponds (Xio nd Gu 1981), nd experiments were of smll scle (Sun et l. 2006). This study exmined bout 13,500 kg of juvenile se cucumbers of three different sizes pcked in 900 cges, mking this the biggest field-bsed trnsplnting experiment in southern Chin. The high survivl t ll densities in this study showed tht trnsporting smll se cucumbers in mss numbers ws logisticlly fesible. In terms of mintennce, removl of fouling orgnisms on the outside of the blone cges periodiclly cn mximise wter flow nd inputs of orgnic sediments to ensure high survivl nd growth rtes of se cucumbers in culture. Hbitts nd culture fcilities should be protected ginst strong storms. The min limiting fctor ppered to be temperture, which becme too high fter April. During the experiment, the optiml temperture rnge for se cucumber growth proved to be C. GR decresed with tempertures bove 17 C fter April. Juvenile size t relese significntly ffected longterm survivl, but survivl ws density-independent within the experimentl rnge (Purcell nd Simutog 2008). There ws high survivl of A. jponicus of ll sizes nd densities in our experiment. Other recent studies hve shown similr results: survivorship of A. jponicus ws high when co-cultured with bivlves in lntern nets (Zhou et l. 2006); high survivorship of Austrlostichopus mollis occurred beneth mussel frm cross ll cging densities (Slter nd Crlton 2007); nd survivl of SPC Beche-de-mer Informtion Bulletin #32 Mrch 2012 bc bc Smll size Medium size Lrge size Ind. lyer-1 Figure 5. Effect of culture density on the growth rte of Aposticopus jponicus during six-month growth experiment est of Shengsi Islnd in Zhejing Province, southern Chin. Different letters indicte significnt men differences (P <0.05), nd brs represent stndrd errors of the mens (n = 4 sites). 37 Prstichopus clifornicus ws 100% in oyster growout trys (Pltzt et l. 2008). A. jponicus preferentilly inhbits bottom res with flourishing mcrolge nd rich detritus, which provides the se cucumbers min feed (Li nd Wng 1994; Zhng et l. 1995). In htcheries, newly settled lrve re commonly fed with ditoms, nd lter, juveniles in nursery tnks re fed with powdered seweed. In Chin, Jpn, Indi nd Indonesi, powdered seweed hs been used for htchery-produced juveniles of A. jponicus nd Holothuri scbr (Sui 1988; Bttglene et l. 1999), nd individuls reched n verge of 40 g on nturlly occurring lge. Thus, it is pproprite to use seweed s food source for se cucumbers. Growth in H. scbr slowed when individuls verged 40 g without ny ddition of seweed in lnd-bsed nursery tnks (Bttglene et l. 1999). Therefore, it is necessry to dd rtificil food for this commercil se cucumber to continue growing. Our results showed tht A. jponicus could grow well on fermented seweed nd other orgnic debris, nd in our experiment, the ddition of fermented seweed improved survivl nd growth of juvenile se cucumbers. GR nd se cucumber density were correlted. Juveniles stunted from being held t densities of 5 7 ind. lyer -1 subsequently grew t the sme rt e s juveniles tht were not stunted t densities of 3 ind. lyer -1. We suggest tht the optiml size nd densities for culturing se cucumbers is 3 5 ind. lyer -1. A. jponicus cn be frmed successfully t size of 40 g, nd fter six months of culturing cn grow to commercil size of 100 g. Kng et l. (2003) demonstrted tht cge-cultured A. jponicus se cucumbers grow well with the chrm blone Hliotis discus hnni in suspended c bc

6 38 SPC Beche-de-mer Informtion Bulletin #32 Mrch 2012 cges; se cucumber survivl ws high, nd blones in co-culture groups grew significntly better thn in monoculture. Zhou et l. (2006) reported tht A. jponicus grew well by feeding on biodeposits from filter-feeding bivlves nd tht co-culture with bivlves in suspended lntern nets could be fesible. Cge culturing of se cucumbers with scllops, nd the extension of the new culture fcility, should be the next trget for mss production of se cucumbers by culturing. Further reserch is needed on the effects of cge culturing of se cucumbers nd other species. There re t lest three dvntges to se cucumber cge-culture in southern Chin: cges re esily ccessible nd cost-efficient; culture fcilities provide reltive protection ginst storms nd predtors; nd the cost of cge-culture is much lower thn tht of plcing stone blocks on mud or snd substrte, s would be required for A. jponicus pond culture in southern Chin. Co-culturing se cucumbers with blone enbles frmers to dd gret vlue to their production. But, much remins to be lerned bout the growth nd survivl of se cucumbers before they cn be mss produced, nd pproprite mngement regimes need to be in plce before this hppens. References Bttglene S.C. nd Bell J.D The restocking of se cucumbers in the Pcific Islnds. p In: Brtley D.M. nd Leber K.M. (eds). Cse studies in mrine rnching. FAO Fishery technicl pper, FAO, Rome. Bttglene S.C., Seymour J.E. nd Rmoffi C Survivl nd growth of cultured juvenile se cucumbers, Holothuri scbr. Aquculture 178: Chen J.X Overview of se cucumber frming nd se rnching prctices in Chin. SPC Beche-de-mer Informtion Bulletin 18: Ito S Studies on the technologicl development of the mss production of se cucumber juvenile, Stichopus jponicus. Bulletin of Sg Prefecturl Se Frming Center 4:1 87. Kng K.H., Kwon J.Y. nd Kim Y.M A beneficil coculture: chrm blone Hliotis discus hnni nd se cucumber Stichopus jponicus. Aquculture 216: Li Y.S. nd Wng Y.L Studies on the living environment nd the selection of se re for Stichpus jponicus. Trnsctions of Ocenology nd Limnology3: Lio Y.L Fun Sinic, Phylum Echinodermt, Clss Holothuroide. Science Press, Beijing, Chin. 334 p. Morirty D.J.W Feeding of Holothuri tr nd Stichopus chloronotus on bcteri, orgnic-crbon nd orgnic nitrogen in sediments of the Gret Brrier Reef. Austrlin Journl of Mrine nd Freshwter Reserch 33: Pltzt D.L., Perce C.M., Brnes P.A. nd McKinley R.S Growth nd production of Cliforni se cucumbers (Prstichopus clifornicus Stimpson) co-cultured with suspended Pcific oysters (Crssostre gigs Thunberg). Aquculture 275: Purcell S.W. nd Simutog M Sptio-temporl nd size-dependent vrition in the success of relesing cultured se cucumbers in the wild. Reviews in Fisheries Science 16: Slter M.J. nd Crton A.G Survivorship nd growth of the se cucumber Austrlostichopus (Stichopus) mollis (Hutton 1872) in polyculture trils with green-lipped mussel frms. Aquculture 272: Slon N.A Echinoderm fisheries of the world: A review. Echinodermt (Proceedings of the Fifth Interntionl Echinoderm Conference). A.A. Blkem Publishers, Rotterdm, Netherlnds p. Sui X Culture nd stock enhncement of Apostichopus jponicus. Agriculture Press, Beijing, Chin. P (in Chinese) Sun J.Z., Zhung D.G. nd Chen L.T Cultivtion of Apostichopus jponicus in the sub-tropicl Nnji Islnd. Journl of Zhejing Ocen University(Nturl Science) 25: (in Chinese with English bstrct) Xio S.X. nd Gu G.C Experiments on southwrd trnsplnttion nd rtificil breeding of the se cucumber Apostichopus jponicus. Journl of Fisheries of Chin 2: (in Chinese with English bstrct) Yingst J.Y The utiliztion of orgnic mtter in shllow mrine sediments by n epibenthic depositfeeding holothurin. Journl of Experimentl Mrine Biology nd Ecology 23: Yun X.T., Yng H.S., Zhou Y., Mo Y.Z., Zhng T. nd Liu Y The influence of diets contining dried bivlve feces nd/or powdered lge on growth nd energy distribution in se cucumber Apostichopus jponicus (Selenk) (Echinodermt: Holothuroide). Aquculture 256: Zhng B.L., Sun D.Y. nd Wu Y.Q Preliminry study on the feeding hbit of Apostichopus jponicus in the rocky cost wters long Lingshn Islnd. Mrine Science 3: (in Chinese with English bstrct). Zhou Y., Yng H.S., Liu S.L., Yun X.T., Mo Y.Z. nd Liu Y Feeding nd growth on bivlve biodeposits by the deposit feeder Apostichopus jponicus Selenk (Echinodermt: Holothuroide) co-cultured in lntern nets. Aquculture 256: