coral reefs

Catching and rearing postlarval cleaner for the aquarium trade: results from a WorldFish Center project in Solomon Islands

C. Hair, R. Warren, A. Tewaki, C. Haro and W. Phillips

Abstract

Between 1999 and 2003, the WorldFish Center in Solomon Islands conducted research into the feasibility of a new fi shery based on the capture and culture of postlarval fi sh for the live fi sh trade. The work was carried out in two phases: a research phase from late 1999 to the end of 2002; and a “fi ne- tuning” phase in 2003. Most of the species were of value to the marine aquarium trade, with very few live reef food fi sh recorded. The most valuable ornamentals were the banded , species. Cleaner shrimp were harvested using crest nets, the method being modifi ed with the addition of a solid, water-retaining cod-end designed to increase survival at capture. Grow-out techniques were improved by rearing the shrimp separately in jars to prevent aggression. The jars were painted black to protect the shrimp from sunlight. An economic model using experimental catch data and farm gate prices indicates that the fi shery based on shrimp, supplemented with small numbers of and fi sh is economically viable. The next step will be setting up a demonstration farm in a village in the Western Province of Solomon Islands.

Introduction grow these fi sh to marketable size. The feasibility of the concept and ran from rationale for harvesting fi sh at this stage 1999 to 2002. During this period, two Coral reef fi sh species form the basis of of their lifecycle is that postlarvae are methods of fi sh harvest were investigated: two markets that utilize live individuals. very abundant before settlement, but the light traps and crest nets. Both of these The live reef fi sh food trade targets process of settlement is accompanied by were originally developed for scientifi c mostly serranids with some lutjanids very high mortality (Carr and Hixon 1995; sampling of competent late stage fi sh and a labrid species. The major markets Doherty et al. in press). This is primarily and invertebrate larvae (Doherty 1987; are in Hong Kong and mainland . due to high predation rates when naïve Dufour and Galzin 1993). Routine The marine aquarium industry trades postlarvae return to reefs following their monthly sampling using both techniques in hundreds of species from dozens of planktonic dispersal phase (Hixon 1991). was carried out for two years. Light families, for markets in the UK, Japan and Harvesting pre-settlers should not affect traps caught almost 93 000 individuals the US. Both trades have been associated natural replenishment to the reefs because belonging to 52 families. Crest nets with over-harvesting and the use of they are removed immediately prior to caught over 150 000 individuals from 83 destructive techniques to harvest fi sh this high mortality. The project was funded families. Of these, only a small part of the (Sadovy and Vincent 2002; Sadovy et al. by the Australian Centre for International catch was of value to the aquarium trade 2003). On the other hand, there is also Agricultural Research (ACIAR) and based (15 per cent for light traps and 5 per cent an urgent need for alternative sustainable at the WorldFish Center station in the for crest nets) and a negligible number of livelihoods in the Asia Pacifi c region. Western Province of Solomon Islands. live reef food fi sh species were recorded. Between February 1999 and December The Australian Institute of Marine Science Marine ornamental species included 2003, the WorldFish Center investigated (AIMS) played an important collaborative juvenile painted lobster (Panulirus the feasibility of a new artisanal fi shery and advisory role. Offi cers from the versicolor) and angelfi sh (Pomacanthus and based on the capture and rearing of Solomon Islands Department of Centropyge species). However, by far the pre-settlement coral reef fi sh for both and Marine Resources (DFMR) also most valuable and abundant ornamentals these markets. Sustainable methods were participated in the study. were the banded cleaner shrimp from the used to capture postlarval fi sh as they genus Stenopus. These were taken almost settled from the plankton and simple The study was divided into two phases. exclusively from crest nets. Stenopus and techniques were used to The fi rst comprised research into the Lysmata shrimp are amongst the ten most

42 NAGA, WorldFish Center Quarterly Vol. 27 No. 1 & 2 Jan-Jun 2004 coral reefs

traded invertebrates worldwide (Wabnitz et al. 2003). They are attractive, relatively N easy to maintain in a tank and perform Ghizo a benefi cial cleaning and scavenging role Island (Wabnitz et al. 2003). Although the life Nusa Tupe cycle of several cleaner shrimp species has been closed, there are a number of Gizo constraints to commercial production of Stenopus species (Calado et al. 2003). Hence, most are still collected from the wild, despite some concern that over- fi shing could have detrimental effects on natural reef ecosystems (Wabnitz et al. 2003). Papua New At the conclusion of the fi rst phase, we Guinea Nusa Nane recognized that there was potential to Solomon 0 1 develop an economically viable fi shery Islands km based on postlarval reef species, primarily . The second phase was Fig.1. Location of the WorldFish Center (Nusa Tupe) and the reef crest (Nusa Nane). through 2003 and was devoted to “fi ne- tuning” the capture and culture methods, specifi cally for high value species. Given that crest nets caught more and higher value species and were cheaper, easier to operate and more reliable than light traps, a modifi ed form of this technique was developed for the new fi shery. In this article, we describe efforts to catch, rear and market banded cleaner shrimp reared from postlarvae in Solomon Islands.

Materials and Methods Study site

The WorldFish Center in Solomon Islands is located at Nusa Tupe near Gizo in the Western Province (Fig. 1). The crest net Fig. 2. Reef crest at Nusa Nane. sampling site was approximately 6 km from the fi eld station on a two-kilometre long reef crest that was exposed at low tide. up to and following the new moon each fi rst research phase: (i) 1.5 mm plankton month, when the highest number of fi sh mesh nets, mouth size 1x1.5 m and 3 m Capture of shrimp are leaving the plankton (Milicich and long with a detachable soft cod-end Doherty 1994; Dufour et al. 1996). The (Doherty and McIlwain 1996), provided Crest nets are small mesh nets fi xed on catch was retrieved early each morning. by AIMS (Fig. 3a) were used until a shallow outer reef crest, immediately February 2001 (Hair et al. 2002a); and (ii) behind the surf zone (Hair et al. 2002a, From November 1999 to September 3 mm knotless mesh nets, mouth size 1 x Fig. 2). They sample fi sh coming through 2001, two crest nets were set during 1.5 m and 3.5 m long, also with a soft the surf zone from the open sea into every new moon period. In 2002 and cod end, were used until the end of the lagoon (Dufour and Galzin 1993). 2003, only some months were sampled. sampling in September 2001 (Fig. 3b). Nets were deployed in the week leading Two types of net were used during the Shrimp catches from the old and new

NAGA, WorldFish Center Quarterly Vol. 27 No. 1 & 2 Jan-Jun 2004 43 coral reefs

nets were compared during the months retained for aquaculture. However, most Jar culture of February and April 2001, and no grow-out trials were carried out in signifi cant difference was found in the 2003. Our observations of cleaner shrimp number of shrimp collected (Hair et al. indicated that their aggressive nature 2002b). Grow-out of shrimp contributed to the high mortality recorded during en masse grow-out. In the fi ne-tuning phase of the work Cage culture To investigate this, shrimp were grown in 2003, a third catching device was individually in 200 ml clear plastic jars developed. The crest nets were modifi ed Due to variable nightly catches and the (Fig. 5). All jars had holes drilled in them by replacing the soft cod end with a uncertainty of catching enough shrimp to facilitate water fl ow but minimize rigid, water retaining cod-end in order for experimental treatments, cleaner food loss. The jars were positively to reduce mortality and improve the shrimp were classed as a single cohort for buoyant. Food was placed in the jars, condition of harvested postlarval rearing if they were caught within three with uneaten food removed and new shrimp (Fig. 3c). During both phases of successive nights. During 2003, different food added twice a day initially. Twice- the project, some cleaner shrimp were types of cages were fi lled with live rock daily feeding was found to be very labor and placed on trestles to keep them off intensive, so the feeding regime was the sea fl oor (Fig. 4). Banded cleaner reduced to once daily with little change (a) shrimp were grown en masse in cages for in survival. periods of 21 days in plastic trays (56 x 31 x 10 cm) lined with 1.5 mm net Although intraspecifi c fi ghting was mesh to prevent escape and predation, eliminated, a new problem emerged as stick frames covered with mesh, and shrimp reared in jars developed algal plastic wastepaper baskets with mesh lids growth on their exoskeleton (Fig. 6). (56 cm high x 31 cm diameter). Shrimp After moulting the shrimp would regain were fed twice daily on a diet of minced normal coloration but quickly start fi sh, and mollusc fl esh. to look “green” again. In addition, an (b) individual fouled with algae often lost As mortality was generally high in appendages or died during moulting. This en masse cage culture, a series of problem appeared to be directly related experiments were designed to investigate to the amount of algal fouling. why. Shrimp were grown in prawn trays in deep versus shallow water and in trays Two experiments investigated the role with separate compartments and with of light as a determinant of algal growth pipe shelters. In another experiment, on the shrimp exoskeleton. First, shrimp shrimp were reared using different were reared in jars in the sea at the (c) feeding regimes: (i) feeding at two-hourly surface (in shaded and unshaded cages) intervals; (ii) feeding twice daily; and (iii) and near the sea fl oor (in shaded and not fed at all. Survival of shrimp in these unshaded cages). Second, shrimp were various treatments was compared after reared in jars that were painted black. three weeks of culture. During these trials, shrimp were checked

Fig. 3. Sampling gear used in the study: (a) original AIMS crest net with soft cod- end; (b) green knotless mesh crest net with soft cod-end; and (c) green crest Fig. 4. Examples of baskets used to rear Fig. 5. Jars used for rearing shrimp net with solid cod-end. shrimp en masse. individually.

44 NAGA, WorldFish Center Quarterly Vol. 27 No. 1 & 2 Jan-Jun 2004 coral reefs

for the amount of algal fouling on their the robustness of the fi nancial result to different growth characteristics and exoskeleton and mortality recorded variations in yield (catch) and market commercial value. daily. value. Catch data Marketing of shrimp Results Temporal variation in crest net catches (1999- The cultured shrimp were shipped by air Identifi cation 2003) to an exporter in Honiara, then exported to the US for sale in retail aquarium Most cleaner shrimp were from the Mean monthly crest net catches stores. During the initial research phase, genus Stenopus, family Stenopidae. Most of cleaner shrimp per night for all specimens were sent to the exporter for small Stenopus postlarvae looked similar new moon periods fi shed between feedback on their value and condition. at capture (Fig. 7a), although larger November 1999 and November 2003 In 2003, fi sh were sold to the marine individuals were distinctive (Fig. 7b). All are shown in Fig. 9. Catches varied aquarium company to verify the quoted individuals could be positively identifi ed greatly, ranging from almost zero in prices for these species. by the third day after capture at the November 1999 and March 2001 to latest. During the research phase, only almost 20 shrimp per net night in Economic model of the fi shery Stenopus hispidus, banded cleaner shrimp September 2003. (Fig. 8a) were recorded. During 2003, An economic model of the postlarval fi sh S. zanzibaricus (gold-banded coral shrimp Comparison of gear types– (2003) capture/culture operation was developed Fig. 8b) and S. tenuirostris (blue-banded by B. Johnston (Queensland Department coral shrimp Fig. 8c) were also captured. Crest nets with solid cod-ends caught of Primary Industries and Fisheries). The identifi cation of extra species was similar or greater numbers of cleaner The model used a discounted cash fl ow attributed to improvements in capture shrimp compared to crest nets with soft analysis to determine the annual cost techniques in this second phase of the cod-ends (Fig. 9). The best survival was structure and the likely profi tability of project. The rare and highly sought-after recorded in the solid cod-ends in all the operation. The model assumed a banded cleaner shrimp, S. pyrsonatus, months (Table 1). project life of 20 years and used a real was not recorded during this study, discount rate of 8 per cent to calculate although a small number of Lysmata the net present value (NPV). The budget amboinensis (Indo-Pacifi c white-striped (a) also incorporated the initial capital and cleaner shrimp, family Hippolytidae) establishment costs. The variables input were captured and reared. Identifi cation into the model included the number is important since different species have of traps, catch rates of banded cleaner shrimp (plus small numbers of lobster and teleosts), landed value of each of the valuable species and costs of capital items (a) (nets and traps), maintenance and labor. A (b) risk analysis was carried out to determine

(b) (c)

Fig. 7. Postlarval Stenopus species: (a) Fig. 8. Adult (export size) Stenopus Fig. 6. Banded cleaner shrimp with algal unidentifi ed postlarvae; and (b) Stenopus species: (a) Stenopus hispidus; (b) fouling on its exoskeleton. zanzibaricus. S. zanzibaricus; and (c) S. tenuirostris.

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Table 1. Average shrimp survival (%) in of shrimp in unshaded jars was at least During 2003, 10 shipments of fi sh, worth solid con-ends versus soft cod-ends twice that of the shaded jars at either a total of $245 were sold. The highest during sampling in 2003. depth. Although slightly higher survival value came from banded cleaner shrimp Treatment Jul. Aug. Sep. Oct. Nov. occurred in surface treatments, this factor with $144 for 146 shrimp. Eighty Solid cod- was less important than shading. Surface netted $79, and 97 fi sh (mostly angelfi sh, 90% 95% 100% 95% 100% end treatments had higher algal levels than puffers and butterfl yfi sh) were worth $21. sea fl oor treatments in both cases and These were taken from about 75 night’s Soft cod- 60% 60% 60% 75% 80% unshaded shrimp grew more algae than fi shing using three nets each night. end shaded shrimp at each depth. Economic model Grow-out trials Once jars were painted black to further reduce light, mortality of shrimp The economic model was run using a Benthic cages fell further and was lower than that range of values in order to confi rm its experienced in clear jars (Table 2). Levels robustness to variations in production Mortality of shrimp grown en masse in of algae on the shrimp exoskeletons was (either due to variable catches or cages on the sea fl oor was calculated also reduced in black jars. fl uctuations in survival during culture) weekly. Very high mortality (between 40 and market price. The parameter values and 80 per cent) was experienced in the S. hispidus grew well in jars and were were based on actual catches of shrimp, early, unreplicated trials. Furthermore, ready for export after about four while lobsters and teleosts were included manipulating depth, type of shelter and weeks at around 25 mm body length. as a supplementary component of the frequency of feeding did not improve Unfortunately, the other species did not fi shery. Capital costs included two traps survival rates: mortality remained grow well in jars and did not reach export at $175 each and $140 for rearing between 60 and 88 per cent. Generally, size, even after two months of grow-out. facilities. A small labor cost was included the greatest number of shrimp died or ($280 per annum) and $700 paid to the were lost in the fi rst week after capture. Value of the catch owner/operator per annum (although Mortality continued throughout grow- it is likely that in the early stages of out, albeit at a lower rate than the fi rst Based on prices quoted by the exporter, operation, the fi sh-farmer will depend week. Mortality remained at similar the estimated value of the crest nets on unpaid family labor, only occasionally levels, regardless of shrimp densities in catch from October 1999 to September withdrawing funds). Experience with the cage. 2001 was $2 7771. Cleaner shrimp village giant clam farming in Solomon accounted for 65 per cent of the potential Islands indicated that paid labor might Jars total value for that period despite making be employed once the operation is up only 13.5 per cent of ornamentals by established and profi table (C. Oengpepa, Results of effects of shading on shrimp number. The farm gate price for cleaner pers. comm). The model indicated that in jars are shown in Table 2. Mortality shrimp was $1.00 each. the fi shery was profi table over a wide

Table 2. Overall mortality (%) during shrimp jar shading experiments in 2003. 24 22 % Av. algal 20 Treatment se) 18 mortality level ± 16 14 Sea fl oor shaded 30-40% 0.4-0.5 12 Surface shaded 20-30% 0.7-0.8 10 8 6 Sea fl oor unshaded 60-100% 0.4-0.8 4 Mean abundance ( Surface unshaded 60-70& 1.1-1.2 2 0 Oct Nov Dec Jan Feb Mar Apr A/M M/J J/J J/A A/S S/O O/N Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Jun Jul Aug Sep Oct Apr MayE MayL Jun Jul Aug Sep Oct Nov Black jars 0-20% 0-0.1 2000 2001 2002 2003 Clear jars 30-40% 0.3-0.6 (n=10 jars in each treatment. Algal level was Fig. 9. Mean nightly abundance per net (±se) per month of banded cleaner shrimp estimated as 0= nil algae; 1=small amount on legs and lobster for all sampling periods from 1999 to 2003. Solid line denotes catches in only; 2=small amount on legs and body; 3=dark soft cod-ends and broken line denotes catches in the solid cod-ends. algae on full body).

1 All values are in US$.

46 NAGA, WorldFish Center Quarterly Vol. 27 No. 1 & 2 Jan-Jun 2004 coral reefs

range of inputs and debt could be mated pairs or isolated in jars (L. Squire, again being provided by ACIAR as part of recovered in the fi rst year. pers. comm.). The observed drop in a larger project that supports sustainable mortality when the shrimp were isolated aquaculture in the Pacifi c region. The lead Discussion in jars suggested that aggression occurs agency is the Department of Primary from around the time of settlement. One Industries and Fisheries in Queensland The marine aquarium trade generates drawback of the jar rearing method is the (DPI), working in close collaboration with $200 to $330 million worldwide each increased likelihood of shrimp growing the WorldFish Center in the Pacifi c and year (Wabnitz et al. 2003). As most algae on their exoskeleton since banded Secretariat of the Pacifi c Community valuable fi sh are sourced from tropical cleaner shrimp are nocturnal and cryptic (SPC). seas in developing countries, it provides in the wild yet exposed to strong sunlight an important source of income to coastal when grown out in jars. The algal growth Acknowledgements communities in the Asia Pacifi c region. was controlled with black jars and shade Unfortunately, specimens are often over the grow-out cages. Growing shrimp This research was funded by the collected using cyanide or destructive in jars is more labor intensive but is a Australian Centre for International fi shing techniques and there are fears that simple procedure and can be handled by Agricultural Research. Special thanks to over-fi shing is occurring for some species most age groups. This is an advantage for Dr P. Doherty of AIMS for supervision in some areas (Sadovy and Vincent 2002). a family run operation in a village. and guidance. We acknowledge the When this project commenced, it was logistical support and advice provided by envisaged that harvesting pre-settlers Cleaner shrimp were the most abundant I. Lane and the WorldFish Center’s Nusa might take pressure off existing coral reef and valuable species we collected Tupe staff for assistance with fi eld populations by providing an alternative throughout the study. The value of the sampling. M. Rimmer provided helpful to the collection of large juveniles and ornamental catch from light traps and comments on the draft manuscript. adults for the trade. Our fi nal results, crest nets from October 1999 to however, suggest this is unlikely. The small September 2001 was $598 and $2 777, References range and relatively low abundance of respectively. Low-value damselfi sh, target species harvested using crest nets predominantly caught in light traps, made Calado, R., L. Narciso, S. Morais, A.L. Rhyne, (and light traps) means that the new up nearly 80 per cent of ornamentals by and J. Lin. 2003. A rearing system for fi shery is more likely to complement number but only 21 per cent of the value. the culture of ornamental decapod the existing dive fi shery, not replace it. Cleaner shrimp made up only 13.5 per crustacean larvae. Aquaculture 218: Nevertheless, it could positively impact cent by number but accounted for 65 per 329-339. the socio-economic situation by providing cent of the total value. Economic Carr, M.H. and M.A. Hixon. 1995. Predation a sustainable livelihood in the region. modeling of the fi shery using actual catch effects on early post-settlement abundances and their real value indicates survivorship of coral reef . Marine The fi nal year of the project was devoted that banded cleaner shrimp could support Ecology Progress Series 124:31-42. to “fi ne-tuning” the catching and rearing a fi shery. There is potential to increase Doherty, P.J. 1987. Light traps: selective methodology to a stage where it could be profi tability if grow-out of the blue- but useful devices for quantifying the introduced to coastal communities. The banded and gold-banded cleaner shrimp distributions and abundances of larval effectiveness of the solid, “fi sh friendly” can be improved and if other species (e.g., fishes. Bulletin of Marine Science 41: cod-end was well demonstrated by the Lysmata) can be targeted. Juvenile painted 423-431. improvement of survival in the catch. crayfi sh and a small range of ornamental Doherty, P.J. and J. McIlwain. 1996. Average survival of shrimp was 10 per teleosts (fi nfi sh) would provide extra Monitoring larval fluxes through the cent between 1999 and 2001 (Hair et income. Additionally, recognition of the surf zones of Australian coral reefs. al. 2002b). In 2003, with fi sh friendly techniques as a sustainable, responsible Marine and Freshwater Research 47: cod-ends, survival rose to 97 per cent. fi shery may lead to certifi cation by the 383-390. Survival of other target species and by- Marine Aquarium Council with Doherty, P.J., V. Dufour, R. Galzin, M.A. catch also improved markedly with solid, subsequent market advantages (Holthus Hixon, M.G. Meekan and S. Planes. 2004. water-retaining cod-ends. Shrimp could 1999). High mortality during settlement is a be maintained in good condition between population bottleneck for a tropical collection at the reef crest and delivery to The next step involves the establishment surgeonfish. Ecology (in press). their grow-out habitat by handling them of a village demonstration farm in the Dufour, V. and R. Galzin. 1993. Colonization gently and separating them at retrieval Western Province of Solomon Islands. If patterns of reef larvae to the from the cod-end. S. hispidus is naturally the operation is a success, the techniques lagoon at Moorea Island, French aggressive and in the ornamental fi sh will be transferred to other countries Polynesia. Marine Ecology Progress trade adults are maintained in tanks as in the region. Funding for this activity is Series 102:143-152.

NAGA, WorldFish Center Quarterly Vol. 27 No. 1 & 2 Jan-Jun 2004 47 coral reefs

Hair C.A., P.J. Doherty, J.D. Bell and M. Holthus, P. 1999. The Marine Aquarium Wabnitz, C., M. Taylor, E. Green and T. Lam. 2002a. Capture and culture of Council, certifying quality and Razak. 2003. From ocean to aquarium. presettlement coral reef fishes in sustainability in the marine aquarium UNEP-WCMC, Cambridge, UK. Solomon Islands. In M. Kasim Moosa, industry. SPC Live Reef Fish Bulletin Wood, E. 2001. Collection of coral S. Soemodihardjo, A. Soegiarto, K. 5:34-35. reef fish for aquaria: global trade, Romimohtarto, A. Nontji, Soekarno, Milicich, M.J. and P.J. Doherty. 1994. Larval conservation issues and management Suharsono (eds.) Proceedings of supply of coral reef fish populations: strategies. Marine Conservation the Ninth International Coral Reef magnitude and synchrony of Society, UK. Symposium, Bali, 23-27 October 2000. replenishment to Lizard Island, Ministry of Environment, Indonesian Great Barrier Reef. Marine Ecology Institute of Sciences and the Progress Series 110:121-134. International Society for Reef Studies. Sadovy, Y.J. and A.C.J. Vincent. 2002. Vol. 2:819-827. Ecological issues and the trades in Hair, C.A., J.D. Bell and P.J. Doherty. live reef fishes, p391-420. In P.F. Sale. C. Hair is from the Queensland 2002b. Development of new artisanal (ed.) Coral Reef Fishes: Dynamics Department of Primary Industries and fisheries based on the capture and and Diversity in a Complex Fisheries, Northern Fisheries Centre, PO culture of postlarval coral reef fish. Ecosystem. Academic Press, San Box 5396, Cairns QLD 4870, Australia. WorldFish Center Final Report to Diego. Email: [email protected]. ACIAR, December 2002. Sadovy, Y.J., T.J. Donaldson, T.R. Graham, R. Warren, A. Tewaki and C. Haro are Hixon, M.A. 1991. Predation as a F. McGilvray, G.J. Muldoon, M.J. from the WorldFish Center, PO Box 77, process structuring coral-reef fish Phillips, M.A. Rimmer, A. Smith and B. Gizo, Solomon Islands; and W. Phillips is communities, p. 475-508. In P.F. Sale Yeeting. 2003. While stocks last the from the Solomon Islands Department of (ed.) The ecology of fishes on coral live reef food fish trade. ADB Pacific Fisheries and Marine Resources, PO Box 77, reefs. Academic Press, San Diego. Studies Series. Gizo, Solomon Islands.

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