Indian Journal of Geo Marine Sciences Vol. 46 (03), March 2017, pp. 569-575

Distribution pattern and community structure of sea cucumbers (Class: Holothuroidea) in different biogeographic regions of the selected Islands of Archipelago,

Idreesbabu K.K.a,b & S. Sureshkumarb,c

a Coral Reef Research Centre, Department of Science and Technology, - 682555, of Lakshadweep, India b Research Centre and Post-Graduate Department of & Fishery Microbiology, MES College, University of Calicut, Ponnani, 679 586, , India c Present Address: School of Ocean Science and Technology, Kerala University of Fisheries and Ocean Studies, Panangad, 682506 , Kerala, India, [email protected]

[ E. Mail: [email protected] ]

Received 15 May 2014; revised 11 November 2016

Distribution pattern and community structure of (Class: Holothuroidea) was investigated in different biogeographic region of three of Agatti, Kavaratti, islands of Lakshadweep archipelago. atra and H. leucospilota were randomly distributed in Agatti while they showed aggregated distribution pattern in Kavaratti and Kalpeni atolls.. richness in Agatti (1.61 ± 0.46) and Kalpeni (1.63 ± 0.82) atolls were comparable and a lower species richness was observed in Kavaratti (1.33 ± 0.42) atoll. Species diversity of Kalpeni (2.1 ± 0.72) was higher than Agatti (2.0 ± 0.57) and Kavaratti (1.6 ± 0.49). The community structure of Sea cucumber in different biogeographic regions of the reef (WSB- Western Sea grass bed, WSA- Western Sandy area, WRF- Western Reef flat, ORS-Outer reef slop, ERS- Eastern Rocky area, ESW- Eastern Seaweed area) differs significantly (P<0.001).

[Key words: Sea cucumber; Kalpeni; Kavaratti; Agatti; Lakshadweep]

Introduction Comprehensive studies on holothurians In the seas around India nearly 200 are essential due to their significant role in the species of holothurians are known, of which about maintenance of the marine environment9. No 75 species are from the shallow waters of these attempts have so far been made to understand the only a dozen species are commercially important1. distribution pattern or quantitative estimation of The holothurians chiefly live in the lagoon and the holothurians resources of Lakshadweep10. The many species live in coral reefs of the present study aimed to bring about scientific data Lakshadweep2. James3 gave a general account on in phase regarding distribution, occurrence and ecology of intertidal holothurians from the Indian quantitative estimation of the holothurian region. The occurrence of holothurians resources resources of Lakshadweep based on the different of the Lakshadweep have been studied in greater biogeographic regions of the reef (WSB- Western detail after conducting a planned survey to all the Sea grass bed, WSA- Western Sandy area, WRF- 10 islands in the Lakshadweep4,5, however studies Western Reef flat, ORS-Outer reef slop, ERS- specific to the quantitative descriptions especially Eastern Rocky area, ESW- Eastern Seaweed area) richness and diversity are totally lacking. Recent and to predict the regions of holothurians attempts on sea cumbers of Indian waters are biodiversity by comparing the richness of the limited to the larval rearing and observation of selected zone. juveniles from east coast of India6,7,8.

570 INDIAN J. MAR. SCI., VOL. 46, NO. 03, MARCH 2017

Materials and Methods Density of species was calculated from Lakshadweep is an archipelago in the 50m×5m of each belt transect assuming complete (8o & 12o 30' N, 71o & 74o E) off the detection of individuals, and averaged over the west cost of India (Figure 1). Lakshadweep replicates. Mean density of each species in the waters harbour rich faunal diversity of vertebrates different zones was then estimated from the and invertebrates11. Present study extended to the transect densities for each atoll. reefs of three atolls of Lakshadweep Archipelago, namely: (1) Agatti (10°51′N 72°11′E) with lagoon area of 17.5 km2; (2) Kavaratti (10°33′N 72°36′E) with lagoon area of 4.96 km2 and (3) Kalpeni (10°4′N 73°38′E) with lagoon area of 25.6 km2 (Fig.2). A total of 72 belt transects12 were surveyed in the atolls covering different geomorphologic zones of Kavaratti, Agatti and Kalpeni islands. Each transect, 50m × 5 m wide, were marked by recording their GPS locations at the start and end points. Direct search method was used to record the occurrence and abundance of Holothurians, at depths ranging from 1m to 30m with the help of snorkeling and SCUBA diving with simultaneous recording by photography,

along the belt transects. Sample specimen of each species were collected and identified following standard references1,10. Fig. 1- Map of Lakshadweep Archipelago. Map not to the scale

2a 2b 2c

Fig. 2-Atolls Selected for the study. 2a- Agatti, 2b- Kavaratti and 2c- Kalpeni. Source: - Centre for Earth science.

Independent sample t-tests were performed Kavaratti and Kalpeni atolls. Aggregation patterns to test the significance of variation in species of different species were analysed from the mean to densities between different zones of Agatti, variance ratios of densities, and tested for any trend

K. & SURESHKUMAR: DISTRIBUTION AND COMMUNITY STRUCTURE OF SEA CUCUMBERS IN LAKSHADWEEP 571 towards clumping or uniformity through Chi square regions of the reef were also worked out. H. atra test of significance using the software Biodiversity- was the abundant (16.00±7.2) species while Pro13. Bray-Curtis similarity method was used to Stichopus herrmanni demonstrated sparse evaluate the distance or similarities in abundance of occurrence (0.33±0.58). Species richness and holothurians in different biogeographic region of diversity index were estimated and compared the atolls. Non metric multidimensional scaling was between the different biogeographic regions of also adopted to find a configuration of points in three atolls (Table 2). The community structure of Euclidean space between the Biogeographic region Sea cucumber in different biogeographic regions of and similarity abundance of the holothurians. Mean the reef (Sea grass bed, Sandy area, Reef flat, outer densities in different Biogeographic region were reef slop, Rocky and rubble area and Sea weed and compared through one-way ANOVA with post hoc algae quarter) differs significantly (P<0.05) . Newman–Keuls test. Species richness in Agatti with Kalpeni atoll exhibit more or less comparable (1.61 ± 0.46) and (1.63 ± Results 0.82) respectively and in Kavaratti species richness During the survey fifteen species of Sea found low (1.33 ± 0.42), when compared with cucumbers belong to seven genera and three Agatti and Kalpeni atoll. Species diversity of families were recorded and their distribution pattern Kalpeni (2.1 ± 0.72) was higher than Agatti (2 ± and densities in different substrata were worked 0.57) and Kavaratti (1.6 ± 0.49). out. Average abundance of Sea cucumber (number per 100 m2) along the different biogeographic

Table 1:- Occurrence and average abundance (number of Sea cucumber per 100 m2 ± SD) along the different biogeographic regions of the reef of Lakshadweep atolls. WSB- Western Sea grass bed, WSA- Western Sandy area, WRF- Western Reef flat, ORS-Outer reef slop, ERS- Eastern Rocky area, ESW- Eastern Seaweed area

Species WSB WSA WRF ORS ERA ESW

Holothuria atra Jaeger, 1833 16.00±7.20 3.67±0.58 8.96±0.58 2.33±0.58 10.33±1.5 3.67±1.53 Holothuria leucospilota (Brandt, 1835) 0 0 0 1.00±00 8.67±4.16 1.67±0.58 Jaeger, 1833 0 4.67±3.06 1.56±0.58 0.67±0.58 0.33±0.58 0.33±0.58 Holothuria nobilis (Selenka, 1867) 0 0 0 2.00±00 0.67±0.58 0 Holothuria hilla Lesson, 1830 1.67±0.58 0 0.75±0.58 0 5.67±2..08 1.00±1.73 Holothuria pervicax Selenka 1867 0 0 0 0 0.67±0.58 0 Holothuria edulis Lesson, 1830 0 0 0 0.33±0.58 0.67±0.58 0 Holothuria cinerascens (Brandt, 1835) 0 0 0 0 0.67±0.58 0.33±0.58 mauritiana (Quoy & Gaimard, 1834) 0 0 0 0 2.00±00 6.00±20 argus Jaeger, 1833 1.33±0.58 0.33±0.58 0.75±0.58 0 0 0.33±0.58 Synapta maculata (Chamisso & Eysenhardt, 1821) 4 0 2.22±0.58 0 0.67±1.15 0 graeffei (Semper, 1868) 0 0 0 3.33±0.58 0 0 Thelenota ananas (Jaeger, 1833) 0 0.33±0.58 0.11±0.58 2.33±0.58 0 0 Stichopus chloronotus Brandt 1835 0.67±1.15 0 0.61±2.31 0 0 0 Stichopus herrmanni Semper, 1868 0 0 0 0 0 0.33±0.58

H. atra found to be distributed in all the were fairly common in different atolls of the selected biogeographic regions of the atolls while archipelago (Table 1). Distribution pattern of Sea Pearsonothuria graeffei restrict their distribution to cucumbers along different atolls showed dissimilar outer reef slope. Species like Holothuria pervicax, pattern, Holothuria atra and H. leucospilota were H. edulis, Thelenota ananas and Stichopus distributed at random in Agatti while they, showed herrmanni were rarely encountered. Bohadschia aggregated distribution pattern in Kavaratti and argus, Holothuria scabra, H. nobilis, H. hilla and Kalpeni. Actinopyga mauritiana and Stichopus herrmanni occurred moderately while Pearsonothuria graeffei exhibited aggregation Actinopyga mauritiana, H. atra, H. leucospilota

572 INDIAN J. MAR. SCI., VOL. 46, NO. 03, MARCH 2017 pattern in all the selected atolls of the study (Table cucumbers can well be ascertained from the MDS 3). plot. Substantiating the cluster analysis, Hierarchical Cluster analysis was aggregation of similar biogeographic zones of performed to find the similarities in different different atolls, with respect to distribution of sea Biogeographic region with respect to the cucumbers were observed in the MDS plot also distribution of sea cucumbers and similarities in (Fig. 6.). abundance of holothurians in different biogeographic region of the atolls. Table 3- Distribution pattern of Sea cucumber along the different atolls of Lakshadweep archipelago. Table 2- Species richness and diversity of sea cucumbers in different biogeographic regions of three atolls of Lakshadweep Species Chi square values and its comparison. Agatti Kavaratti Kalpeni

Habitat N Species Species Holothuria atra 10 40.8* 26.2* Richness Diversity Holothuria leucospilota 11 39* 44.6* Western Sea grass bed 12 0.79a 1.23a Holothuria scabra 11 7 19.7* Holothuria nobilis 8 7 11 Western Sandy area Holothuria hilla 10.2 11 24* 12 1.10ab 1.38a Holothuria pervicax 5 0 5

Western Reef flat Holothuria edulis 0 5 4 12 1.39abc 1.82ab Holothuria cinerascens 5 6 5 Outer reef slope 12 1.85bc 2.28bc Actinopyga mauritiana 22* 30.8* 16*

Eastern Rocky and Bohadschia argus 4 4 7 c bc rubble area 12 2.01 2.44 Synapta maculata 7 17.8* 15.7* Pearsonothuria graeffei 20* 15* 15* Eastern Sea weed area 12 2.11c 2.54c Thelenota ananas 11 10 7 Stichopus chloronotus 20* 0 10 Sig 0.000 0.000 Stichopus herrmanni 5 0 4 Values with different superscript vary significantly (P<0.05) *Values showed aggregated distribution pattern and remaining values showed random distribution. Interestingly, all the different habitats in various islands can well be grouped at 60% similarity based on the distribution and occurrence of sea cucumbers. Holothuria pervicax and H. cinerascens exhibited 80% similarities in their distribution in different biogeographic regions, while Bohadschia argus and Stichopus chloronotus exhibited 49.13% similarity. Stichopus herrmanni showed a different distribution patters as it showed only 9.51% similarity with all other 14 species of holothurians considered (fig 4). Non-metric Multi-Dimensional Scaling

(MDS) also bring out the similarity in distribution Fig. 3- Dendogram showing the similarities in different pattern of different species of sea cucumbers in the Biogeographic region of selected atolls of Lakshadweep atolls of Lakshadweep (Fig. 5). Distribution pattern Archipelago with respect to occurrence of Sea cucumbers. A- Agatti, KV-Kavaratti, KL-Kalpeni, WSB- Western Sea grass of Stichopus hermanni is distinctly different from bed, WSA- Western Sandy area, WRF- Western Reef flat, other group as positioning away from other species. ORS-Outer reef slop, ERS- Eastern Rocky area, ESW- Eastern Similarity in distribution of different species of sea Seaweed area

K. & SURESHKUMAR: DISTRIBUTION AND COMMUNITY STRUCTURE OF SEA CUCUMBERS IN LAKSHADWEEP 573

stress value obtained during the analysis is very low which denotes good ordination of both the plots.

Discussion In India research on sea cucumbers are limited to the taxonomic attempts and qualitative descriptions from localized area. Though holothurians resources of Lakshadweep was well studied4,5, resource quantification and distribution gained no attention. Recent attempts on breeding 6,7 Fig. 4- Dendogram showing the similarities in abundance of and rearing of sea cucumbers bring out promising holothurians in Lakshadweep Archipelago results for its aquaculture. However, the distribution pattern, region of occurrence and abundance of this important resources have not been explored scientifically, in spite of the facts that these data is important for the formulating conservation strategies and protection measures. When considering the fact that many of the holothurians are categorized as threatened by IUCN, it is high time to estimate the population size, resources and densities of this resources in important localities where sea cumber resources are reported. The present study showed that the distribution of sea cucumbers was more or less similar in all the atolls studied. It is evidenced by Fig. 5- MDS plot showing the similarities in distribution of different species of sea cucumbers in selected atolls of the strong aggregation of similar habitats of Lakshadweep Archipelago. different islands in MDS plots. However, there is significant variation in the occurrence of holothurians in different habitats of the atolls. Habitat wise variability showed by the sea cucumbers may be due to the difference in availability of food. Wolkenhauer9 pointed out the ecological significance of the sea cucumbers and opined that sea grass systems may suffer in the absence of holothurians. Baseline information for the comparison of the present data is totally lacking and exhaustive surveys for the documentation of the diversity and distribution as well as for the quantification of the Holothurian resources of Indian waters are much needed. Fig. 6- MDS plot showing the similarities in different Biogeographic region, different habitats for biogeographic region with respect to the abundance of sea cucumber, of all the selected atolls exhibited holothurians. A-Agatti, KV-Kavaratti, KL-Kalpeni, WSB- Sea 60% similarity in the distribution of holothurians grass bed, WSA- Sandy area, WRF- Reef flat, ORS-Outer reef slop, ERS- Rocky area, ESW- Seaweed resources. Maximum diversity and species richness was observed eastern side of the atoll and outer reef Forty percentage similarity was observed in the slope, where there in minimum anthropogenic distribution of sea cucumbers in the eastern side of intervention. Lagoon and reef flats of the western the island. Outer reef slope of all the atolls have a side of the atolls, where fishing and other human distinct distribution pattern of sea cucumbers. The interventions are more, have lower diversity and species richness of sea cucumbers. Since an

574 INDIAN J. MAR. SCI., VOL. 46, NO. 03, MARCH 2017 organized commercial fishing of sea cucumbers has services and importance of this species to the reef not been reported from Lakshadweep waters, system to develop a self-imposed conservation anthropogenic disturbances in the habitat may be attitude towards this threatened species. Further the prime reason for differential occurrence of these attempts on the biology and larval distribution this resources. It can further attribute that eastern side species in Lakshadweep waters required be initiated and outer reef slope of the atolls have dense and to effectively implement the conservation diverse reefs and algae covered rocks with great measures. number of microhabitats while sea grass bed and sandy area in the western side are exposed resulted Acknowledgement in low holothurian diversity. Authors gratefully acknowledge the Most prized sea cucumbers like Holothuria Department of Environment, UT of Lakshadweep scabra and Holothuria nobilis are common in the for the permission to conduct the survey. The region like Sandy area, reef flat and outer reef slop service of Mr. Sayed Abdulla Koya, Mr. I. of the selected atolls. Pearsonothuria graeffei Nasarulla and Mr. Karamathulla S. for the survey showed their distribution restricted to the outer reef and field work is also gratefully acknowledged. slop of the atolls. Holothuria atra and Holothuria leucospilota exceedingly abundant in sea grass bed References and rocky area of the intertidal zones. The base line 1 James D.B. Twenty sea cucumbers from seas around information development on the distribution and India. Naga ICLARM Quarterly 24 (2001) 4–8. 2 Mannadiar E.S. (Ed.). Lakshadweep. Gazetteer of diversity of the holothurians in different India. Administration of Union Territory of biogeographic region can be a used for the Lakshadweep. Kavaratti, 375p (1977). development of conservation strategy and measures 3 James D.B. Ecology of intertidel of the for the management of the holothurian resources of Indian Seas. Journal of the Marine Biological the Lakshadweep. However the information on the Association of India, 24 (1982) 124–128. 4 James D. B. Echinoderms of Lakshadweep and their temporal distribution and diversity of the sea zoogeography. Bull. Cen. Mar. Fish. Res. Inst., 43 cucumber resources are still lacking from Indian (1989a) 97-144. waters. Since the holothurians have a planktonic 5 James D. B. Beche-de-mer resources of larval stage, cross reef distribution may help in the Lakshadweep. Bull. Cen. Mar. Fish. Res. Inst., 43 (1989b) : 144-149. substantial recruitment and population sustenance. 6 Asha P. S. and Muthiah P. Growth of the hatchery- Though the sea cucumber are protected under produced juveniles of commercial sea cucumber wildlife protection act 1972 and categorized under Holothuria spinifera Theel. Aquaculture Research, IUCN as threatened species, an alarming report of 38 (2007) 082-1087. poaching of this species from Cheriyapani reef of 7 Asha P.S. and K. Diwakar. Effect of stocking density on hatching rate, larval and early juvenile Lakshadweep archipelago with seizing of about rearing of edible sea cucumber Holothuria scabra 14 2000kg from a Sri Lankan boat recently , which Jaeger Indian Journal of Marine Science, 42 (2013) have serious impact on its population and 191-195. community structure. 8 Asha P.S., K. Diwakar and Mary K. Manissery. Observation on juvenile sea cucumber occurrence in the shallow waters of Erstwhile Pandian Island (Hare Conclusion Island) , Tuticorin. Mar. Fish. Infor. Serv. T and E The resource quantification of sea Ser., 215 (2013) 11-12. cucumbers achieved and distribution pattern 9 Wolkenhauer S.M., Uthicke S., Burridge C., Skewes T. Pitchera R. The ecological role of Holothuria derived for selected atolls will be useful for the scabra (Echinodermata: Holothuroidea) within development of conservation strategies and subtropical seagrass beds. Journal of the Marine management policies. Recent reports of poaching of Biological Association of the United Kingdom. 90 the species and habitat destruction due to coral (2010): 215-223. 10 James D.B. and James P.S.B.R. A handbook on beaching and related phenomenon pointing towards Indian sea cucumbers. CMFRI Spl. Pub., 59 (1994) the need for further attempts on population 1-46. estimation and conservation of the species. Since 11 Suseelan C. (Ed.) Marine Living resources of the occurrence of the species is more site specific Lakshadweep. Bull. Cen. Mar. Fish. Res. Inst., 43 the area for protection of the species can well be (1989) p270. 12 Brock V.E. A preliminary report on a method of demarcated. Immediate measures should be taken estimating reef fish populations. Journal of Wildlife to make aware of the Islanders on the ecosystem Management, 18 (1954) 297-308.

K. & SURESHKUMAR: DISTRIBUTION AND COMMUNITY STRUCTURE OF SEA CUCUMBERS IN LAKSHADWEEP 575

13 McAleece N., Lambshead P.J.D., Paterson G.L.J., 14 Lakshadweep Times, Published by Lakshadweep Gage J.D. Biodiversity Pro: Free Statistics Software Administration, Vol XXIX. No 15 Kavaratti, for Ecology. The Natural History Museum & The Wednesday 16th April 2014 (2014). Scottish Association for Marine Science. U.K. (1997).