Spermonde Archipelago Research Articles

Investigating law enforcement for coral reef conservation of the Spermonde Archipelago, Indonesia

The coral reef ecosystem in the Spermonde Archipelago manifests great potential in ecosystem services. However, it has been degraded to “severely damaged”. In this study we investigated the law enforcement related to coral reef conservation, especially the damage caused by destructive actions. We used mixed qualitative and quantitative methods. We explored existing laws, conductedsemi-structured interviewswith6 informants (five fishermen and one judge), collected data on regional convictions data,and surveyed 48 respondents with a quantitative questionnaire, in 5 sampling sites: South Galesong District, Takalar Regency; KodingarengLompo Island,Sangkarrang District Makassar city, Kapoposang Island; Sarappoand Papandangan Island; PangkajeneandKepulauan Regency. This study detected 26 destructive cases, in which the perpetrators were found guilty by the court with the consideration that their actions damaged the coral reef ecosystem. The perpetrators used bombs, cyanide, and cantrangnets to catch fish and collect corals for trading. The imposed sentence was mild and far from the maximum penalty, both in imprisonment and fine. Notably, none of the perpetrators were sentenced to half of the main legal threats. 96% of (n = 48) respondents in our study area disagreed with the mild penalty. A mild penalty may not provide deterrent effects to the perpetrators or others who have an intention to conduct similar activities.The questionnaire showed that most of the locals know about the conservation area (66%) and its regulation (88%). The best solution to strengthen the conservation effort is to quickly establish a fisheries court in Spermonde Archipelago, which is also supported by locals (92% agreed to the establishment). A fisheries court could examine, adjudicate, and decide fisheries criminal cases, such as illegal fishing and destructive fishing within their jurisdiction. The court could be established by Presidential Decree and it will be under supervision of the Supreme Court of Republic of Indonesia.

Biological Activities and Metabolite Profiling of Polycarpa aurata (Tunicate, Ascidian) from Barrang Caddi, Spermonde Archipelago, Indonesia

Biological Activities and Metabolite Profiling of Polycarpa aurata (Tunicate, Ascidian) from Barrang Caddi, Spermonde Archipelago, Indonesia

Arrangement of Makassar City Water Sports Tour Packages based on Geographic Information Systems

This study aims to model the Tirta Tour package in Makassar City. This research method uses a qualitative approach, the data sources are obtained through surveys with field notes, interviews and documentation, while the data processing techniques use the help of ArcGIS 10.5 software. The data collection techniques used in this study are: Focus Group Discussion (FGD), interviews, study comparison and literature study were used for qualitative data. Based on the processed data, it was found as follows: 1) Water tourism potential in Makassar City as a result of analysis 3A: Accessibility, Amenity and Activities in general, the cluster of islands in the Spermonde Archipelago has the potential to become superior marine tourism with current conditions it can be said to be natural. heritage landscapes. 2) Mapping model for Tirta Tour Packages in Makassar City in the form of Tirta Travel Routes with a Stopover Movement Pattern with 4 Tourist Attractions. This study recommends the preparation of an online water tourism information system for Makassar City so that it can be accessed anytime and anywhere.

Microdebris in Echinodea Tripneustes gratilla at Spermonde Archipelago, South Sulawesi, Indonesia

Microdebris contamination of marine organism has become a major concern. As a detritivore, Tripneustes gratilla also has the opportunity to be contaminated. This study aims to determine microdebris contamination in T. gratilla, including the form and size of the microdebris. This research was conducted at three islands, i.e. Barrang Lompo, Badi, and Kondong Bali. Ten individuals were collected from each island. The digestive tract of spesies was taken, then H2O2 was added to dissolve the organic matter. Flotation was carried out by adding NaCl. Microdebris was observed using stereo microscope, and selected particle then was analysed by FT-IR Microscope. The abundance of microdebris in T. gratilla was ranged from 3.4 to 14.8 particles/individual. Tripneustes gratilla from Badi Island showed the highest levels, contained 14.8 particles/individual. Fiber and fragment were found in all the samples. Fiber was the most common microdebris and consisted of more than half of the total microdebris in each island, except Barrang Lompo. The most common size of microdebris ranged 0.05-1mm, accounted for 36% of the total microdebris. The particle observed by FT-IR Microscope was identified as cotton. Our results suggest that microdebris pollution have contaminated T. gratilla in the Spermonde archipelago.

Dynamics of large benthic foraminiferal assemblages: A tool to foreshadow reef degradation?

Ecological regime shifts in the marine realm have been recorded from a variety of systems and locations around the world. Coral reefs have been especially affected, with their benthic habitat changing from a dominance of stony corals to a dominance of other organisms such as fleshy algae. To detect changes in the benthic habitat of coral reefs, simple tools applicable on a global scale are necessary for future monitoring programs. Hence, the aim of this research is to explore the hypothesis that shifts in assemblages of large benthic foraminifera (LBF) can detect early signs of degradation in the reef benthic habitat. To do so, data on living assemblages of LBF collected between 1997 and 2018 at 12 islands in the Spermonde Archipelago (South Sulawesi, Indonesia) were analyzed. Foraminiferal specimens were morphologically identified to the species level and statistical analyses performed to assess changes in their assemblage composition. A clear temporal shift was observed. Typical foraminiferal assemblages in a coral-dominated (e.g., Amphistegina lobifera, Calcarina spengleri, Heterostegina depressa) and fleshy algae-dominated (e.g., Neorotalia gaimardi, C. mayori) reef habitats were identified and significantly linked to the substrate type. Other species (e.g., Elphidium spp., Peneroplis planatus and Sphaerogypsina globulus) seem to reflect a spatial and temporal gradient of anthropogenic pollution from local inhabited islands and ongoing urban development on the mainland. Hence communities of LBF consistently follow gradual shifts in environmental conditions. Additionally to foraminiferal assemblages being an indicator for actual reef condition, closely monitoring LBF may provide early information on reef degradation, in time to take action against identified stressors (e.g., eutrophication or intensive fishing) at local and regional scales. The circumtropical distribution of LBF is such that they can be included worldwide in reef monitoring programs, conditional to calibration to the regional species pool.

Legal regulation on protecting marine environment from sea sand mining impact: a case study of spermonde archipelago

The dilemma between development interest, economical gain and preserving the marine environment from the implication of sea sand mining activity has been primarily discussed in the last decade. In essence, the sea sand mining which jeopardizes the marine environment occurs due to sand dredging activity which contributes to abrasion, removal of corals and marine habitat that plays an important role to the continuity of the majority of fishermen activity in coastal society through observing from several previous sea sand mining cases, including the current situation in Spermonde archipelago. This article is purposed to analyze legal regulation in protecting marine environment from sea sand mining in relation to the current situation in Spermonde archipelago. It applies normative legal research and uses a study case approach. The result shows that the existence of the loopholes in legal regulation on protecting marine environment from sea sand mining is still prominent. Thus, the coastal society in Spermonde archipelago has been negatively impacted by the sea sand mining activity. Pertaining plausible legal effort on such sea sand mining activity, local community are able to file a strict liability lawsuit to the concession permit owner.

Shallow‐marine carbonate cementation in Holocene segments of the calcifying green alga Halimeda

AbstractEarly‐diagenetic cementation of tropical carbonates results from the combination of numerous physico‐chemical and biological processes. In the marine phreatic environment it represents an essential mechanism for the development and stabilization of carbonate platforms. However, diagenetic cements that developed early in the marine phreatic environment are likely to become obliterated during later stages of meteoric or burial diagenesis. When lithified sediment samples are studied, this complicates the recognition of processes involved in early cementation, and their geological implications. In this contribution, a petrographic microfacies analysis of Holocene Halimeda segments collected on a coral island in the Spermonde Archipelago, Indonesia, is presented. Through electron microscopical analyses of polished samples, this study shows that segments are characterized by intragranular cementation of fibrous aragonite, equant High‐Mg calcite (3.9 to 7.2 Mol% Mg), bladed Low‐Mg calcite (0.4 to 1.0 Mol% Mg) and mini‐micritic Low‐Mg calcite (3.2 to 3.3 Mol% Mg). The co‐existence and consecutive development of fibrous aragonite and equant High‐Mg calcite results initially from the flow of oversaturated seawater along the aragonite template of the Halimeda skeleton, followed by an adjustment of cement mineralogy towards High‐Mg calcite as a result of reduced permeability and fluid flow rates in the pores. Growth of bladed Low‐Mg calcite cements on top of etched substrates of equant High‐Mg calcite is explained by shifts in pore water pH and alkalinity through microbial sulphate reduction. Microbial activity appears to be the main trigger for the precipitation of mini‐micritic Low‐Mg calcite as well, based on the presumable detection of an extracellular polymeric matrix during an early stage of mini‐micrite Low‐Mg calcite cement precipitation. Radiocarbon analyses of five Halimeda segments furthermore indicate that virtually complete intragranular cementation in the marine phreatic environment with thermodynamically/kinetically controlled aragonite and High‐Mg calcite takes place in about 100 years. Collectively, this study shows that early‐diagenetic cements are highly diverse and provides new quantitative constraints on the rate of diagenetic cementation in tropical carbonate factories.

CORAL REEFS ON INHABITED AND UNINHABITED SMALL ISLANDS, SPERMONDE ARCHIPELAGO, INDONESIA

Abstract. The small islands in Indonesia is providing important ecosystem services. It is important to identify damages of a coral reef ecosystem and whether natural factors or anthropogenic factors are the main causes. Landsat images obtained with different sensors were analyzed for mapping coral reef on inhabited and uninhabited small islands, Spermonde archipelago, Indonesia. Overall accuracies of three habitats classification were 89.2% and 85.6%, respectively. They are live coral, dead coral and non-coral. Ground truth surveys were selected by using the unsupervised classification method The live coral in inhabited islands was slightly greater than in uninhabited. An increasing area of live coral was about 5.3 ha of the total area in 1990 per year while a decreasing of dead coral was 3.5 ha per year in inhabited islands. In uninhabited island, a decreasing speed of live coral habitat area was about 0.6 per year. During 29 years, a significant increase in the dead coral and decrease in live corals. It has been identified that the significant controlling factor for the disturbances in reef ecosystem is derived from natural and anthropogenic.

Sea urchin identification in Kodingareng Lompo waters, Spermonde Archipelago

Sea urchin, belongs to Phylum Echinoderm, Class Echinoidea. It is categorized as benthic marine invertebrates, and could be found in several ecosystem from shallow water to abyssal depth. Despite the high potential, there is no detail information of this organism in Indonesia, especially in Spermonde Archipelago, South Sulawesi Region. This study aim to identify the sea urchin species found in Kodingareng Lompo Island, Spermonde Archipelago. Kodingareng Lompo is one of the islands belong to Sangkarang Regency, Makassar city. Sampling was done during July 2020. Samples were collected randomly in seagrass bed and transition area. The morphological identification was conducted at the main island. The morphological traits of sea urchin samples collections were observed, noted, and compared with some literatures for identification. There three kind of sea urchin found in this waters: Diadema setosum, Mespilia globulus and Tripneustes gratilla.

Changes in seagrass carbon stock: implications of decreasing area and percentage cover of seagrass beds in Barranglompo Island, Spermonde archipelago, South Sulawesi, Indonesia

Seagrass ecosystems in shallow waters, including in highly dense small islands, are vulnerable to anthropogenic activities and may lead to a decreasing in seagrass area and percentage cover. As a result, it will negatively affect climate change mitigation, i.e. a decrease in seagrass carbon stock. This research was conducted to evaluate seagrass carbon stock changes in Barranglompo Island, Spermonde archipelago, in 2001 and 2017. Carbon stock estimation was carried out by collecting seagrass biomass based on the category of a sparse, medium, and dense seagrass coverage (each with 20 replications) and analysing their carbon concentrations. Changes in carbon sequestration were analysed using an estimated approach to the changes in the seagrass bed areas. Landsat and Worldview-2 image analysis were utilized to estimate the area of seagrass beds in 2001 and 2017, respectively. Results showed a decrease in seagrass beds by 9.9 ha, from 66.8 ha in 2001 to 56.9 ha in 2017, or an average of 0.62 ha per year. Based on that, it was estimated that seagrass carbon stocks had declined from 74.19 tons in 2001 to 65.21 tons in 2017 or decreased by an average of 0.75% per year. Anthropogenic activities, such as boat anchors as well as household waste disposal in the seagrass area, are considered having the potential in causing a decrease in seagrass area and the percentage coverage.

Antibacterial assay of crude extracts from marine sponge Haliclona fascigera in Badi Island of Spermonde Archipelago against shrimp pathogenic bacteria

The marine Sponge Haliclona fascigera, belonging to the genus Haliclona, Family Haliclonidae, Order Haplosclerida, is a source of potentially valuable marine natural products, including diverse bioactive secondary metabolites. These bioactive secondary metabolites could be used as alternative antibiotics for managing pathogenic bacteria in aquaculture. The study aimed to determine the in vitro antibacterial activity of n-hexane, ethyl acetate, and acetone crude extracts against three shrimp pathogenic bacteria and to carry out phytochemical screening. The three crude extracts were produced from H. fascigera collected around Badi Island, Spermonde Archipelago, Indonesia. The crude extracts were screened for their activity against three shrimp pathogenic bacteria: Vibrio harveyi (M-120), Vibrio alginolyticus, and Vibrio parahaemolyticus (T-170). Antibacterial activity assays used the agar diffusion method; the paper discs were impregnated with extract concentrations of 2μg/25μL. Phytochemical screening was carried out using standard protocols to provide supporting data. N-hexane and acetone crude extracts of H. fascigera were able to inhibit Vibrio parahaemolyticus with inhibition zone diameters of 8.07mm and 7.62mm, respectively. The inhibition zone of Ciprofloxacin (positive control) was 10.45 mm. The phytochemical analysis indicated that steroid, terpenoid, and alkaloid compounds were present in H. fascigera. Further studies are needed to reveal the compounds causing the observed antimicrobial effect.

Development of a benthic spatial ratio index as an indicator of small island deformation

The ability of coral reefs and seagrass beds to reduce wave energy positions these ecosystems as the most reliable natural protection for many small islands, especially for coral islands and atolls. With coral damage reaching 174 hectares per year, there must be changes in the spatial composition of coral reefs and seagrass beds around many small islands in the Spermonde Archipelago, changing the shape of the islands and reducing the quality of life of their inhabitants. This study aimed to map the spatial composition of benthic substrates (coral reefs, seagrass beds, and macroalgae) around small islands over time, and to relate changes in substrate composition to island shape change. The initial study was conducted at Barrangcaddi island from July to December 2018. Three field surveys collected spatial data on benthic substrates (coral, seagrass, macroalgae), bathymetry, waves, tides, and beach profiles. The satellite data used were Sentinel 2 images from 2015 to 2018. Satellite image processing included atmospheric correction using the DOS method, land masking, geomorphic segmentation, and classification using the maximum likelihood, Self Organizing Map and Segmentation methods. Thirteen benthic substrate classes were validated with thematic accuracy ranging from 86% to 95%. The land area of Barrangcaddi Island changed around 6 percent from 2015 to 2018. The benthic spatial ratio index for Barrangcaddi Island shows that the north side of the island was the most vulnerable to coastal abrasion, and the existing benthic substrate is no longer effective in reducing the wave energy that hits the island from this side.

Preliminary assessment of Tripneustes gratilla populations in Seagrass Beds of the Spermonde Archipelago, South Sulawesi, Indonesia

Many sea urchins, including the collector urchin Tripneustes gratilla, are well known for their role as herbivores, contributing to the control of fast growing macroalgae that can potentially overgrow and dominate seagrass beds and reef flats. Tripneustes gratilla is a short-spined sea urchin that can be easily found and collected by hand from the seagrass meadows which are their main habitat, especially during low tide. The exploitation of this species in Indonesia began to expand several years ago when the demand for T. gratilla gonads started to rise, for both commercial purposes and household consumption. This study aimed to determine the population and distribution of T. gratilla in seagrass ecosystems with different conditions across the Spermonde Archipelago, South Sulawesi, Indonesia. The results indicate that T. gratilla population abundance and size distribution are affected by several factors: seagrass condition, water quality, and the intensity of sea urchin collection. The results also emphasize the urgent need for developing and implementing effective management to ensure the sustainability of this important sea urchin species.

Large scale study of benthic communities in Eastern Indonesia’s reef systems

Broad-scale studies and regional comparisons of Indonesia’s coral reefs are critical given the relative lack of information about these large, diverse, and threatened ecosystems. Most studies on reef benthic composition and distribution have largely focused on rather short transects spanning relatively small areas. Here, we quantify the shallow large-scale spatial distribution of benthic communities in four locations in Eastern Indonesia, i.e. the Spermonde Archipelago in South Sulawesi, and Ambon, Halmahera and Lucipara in Maluku Islands. Shallow coral reef ecosystems (0.5-2 m depth) were assessed using a georeferenced photoquadrat survey method that can cover larger proportions of reefs, as well as benthic assemblages in deeper reefs (∼8 m depth) recorded with photoquadrats. A total of 27.8 km of shallow and 4.8 km of deeper reef ecosystem transects were surveyed in this study. We found that reef benthic communities at the study locations were mainly characterized by low to moderate cover of live hard corals and relatively high cover of dead corals or abiotic components. Ninety percent of the surveyed reefs at both depths exhibited < 50% cover of live hard corals, whereas 88% of shallow and 78% of deeper reef sites consisted of > 25% dead corals or abiotic components. A combination of georeferenced photoquadrats and CoralNet machine learning rapidly identified benthic composition across a large area, which is useful for mapping or other large-scale applications. This information can support decision-makers for better management of resources and marine spatial planning, crucial for an archipelagic state with tens of thousands of islands such as Indonesia. Our broad-scale reef surveying, focusing on under-studied areas of Indonesia, can contribute to this effort, as well as others seeking to better map coral reef habitats, as an important foundation for their conservation amidst growing threats.

Gonad maturity and gonadal somatic index of blue swimming crab Portunus pelagicus harvested from Spermonde Archipelago, South Sulawesi, Indonesia

Reproductive biology is one of the biological aspects that needed to formulate responsible management of blue swimming crab (BSC). The crab is one of the commercial fisheries commodities in South Sulawesi, Indonesia. Presently no information on the reproductive biology of this crab from Spermonde Archipelago, Sout Sulawesi. Therefore, the study aimed to analyze and compare gonad maturity stage(GMS)andgonadalsomaticindex(GSI)oftheBSCcaughtonthreeecosystemsnamelycoralreef,seagrass,andmangrovein Salemo Island, Spermonde Archipelago. GMS and GSI were analyzed descriptively for five months from March to July 2015. Results indicate there was a difference in GMS of the BSC caught in mangroves, seagrass, and coral reef. Generally, mangrove was dominated by immature BSC with GMS I and GMS II, while the BSC caught in the seagrass and coral reef BSC were dominantly mature and spawn GMS III, IV, and V. GSI BSC caught in mangrove ecosystem are smaller than GSI BSC caught in seagrass and coral reef ecosystems. Seagrass and coral reef ecosystems suitable for development no-take zone of the BSC.

Differences in genetic diversity and divergence between brooding and broadcast spawning corals across two spatial scales in the Coral Triangle region

The Coral Triangle region contains the world’s highest marine biodiversity, however, these reefs are also the most threatened by global and local threats. A main limitation that prevents the implementation of adequate conservation measures is that connectivity and genetic structure of populations is poorly known. The aim of this study was to investigate the genetic diversity, population structure and connectivity patterns of tropical corals in Indonesia on two different spatial scales, as well as by comparing two different reproduction strategies. Genotyping was based on microsatellite markers for 316 individual Seriatopora hystrix colonies and 142 Acropora millepora colonies sampled in Pulau Seribu and Spermonde Archipelago in 2012 and 2013. Differences in allelic diversity and a strong signature of divergence associated with historical land barriers at the Sunda Shelf were found for the brooding coral Seriatopora hystrix. However, differences in diversity and divergence were not pronounced in the broadcast spawning coral Acropora millepora. Within Spermonde Archipelago, two groups were identified: (1) sites of the sheltered inner-shelf and mid-shelf, which were found to be highly interconnected and (2) mid-shelf and outer-shelf sites characterised by higher differentiation. These patterns of contemporary dispersal barriers and genetic diversity can be explained by the differences in life history of the corals, as well as by oceanographic conditions facilitating larval dispersal. The contemporary dispersal barriers found within the Spermonde Archipelago emphasise the need for incorporating connectivity data in future conservation efforts.

Assessing Indicators and Limitations of Food Security Objectives in Coral Reef Restoration

Coral reef restoration is often presented as a marine conservation solution that provides ‘win-win’ outcomes. However, most studies on reef restoration have focused on the biological success, while little is known about whether social objectives are ever achieved. This study investigates a reef restoration initiative in the Spermonde archipelago, Indonesia, where food security was initially presented as an intended social outcome. We utilised an ethnographic mixed-methods approach to investigate: 1) perceived sociocultural benefits of coral restoration to the local community; 2) impacts of reef restoration on local food security; and 3) local sociocultural barriers and limitations of reef restoration as a mechanism for improving food security. We found fish contributed to food security primarily as an income source to purchase food. Local people mainly valued nearby reefs for storm protection. Furthermore, most fishers are organised through patron-client systems that target pelagic species; therefore they currently have minimal dependency on adjacent reefs. However, fishing restrictions linked to the restoration programme still negatively impacted both pelagic fishers and a small population of reef-based fishers—indirectly by damaging reciprocal fishing relations with neighbouring islands and directly by limiting access to local reefs. Complex social and trade networks associated with patron-client networks present potential barriers for transitioning to reef-based fisheries and eradicating the use of destructive fishing gear, therefore limiting access to potential food security benefits generated from reef restoration. These findings show that the relationship between coral restoration and food security is tenuous and cannot be assumed. These findings also demonstrate that social dynamics surrounding community-based conservation initiatives are complex and context-dependent, and such details must be considered when designing marine habitat restoration initiatives.

Presence and Genetic Identity of Symbiodiniaceae in the Bioeroding Sponge Genera Cliona and Spheciospongia (Clionaidae) in the Spermonde Archipelago (SW Sulawesi), Indonesia

Members of the family Symbiodiniaceae form symbiotic relationships with several metazoan groups on coral reefs, most notably scleractinian corals. However, despite their importance to the health of coral reefs, their relationship with other host organisms such as bioeroding sponges (Clionaidae) is still relatively understudied. In this study we investigate the presence and identity of Symbiodiniaceae in Clionaidae species in Indonesia and evaluate findings related to the evolution and ecology of the host-symbiont relationship. Clionaidae were collected throughout the Spermonde Archipelago in Indonesia. Morphological and molecular techniques were used to identify the sponge host (28S ribosomal DNA) and their Symbiodiniaceae symbionts (ITS2). Seven Clionaidae species were found, of which four species contained Symbiodiniaceae. Cliona aff. orientalis, Cliona thomasi and Spheciospongia maeandrina were host to Cladocopium, while Spheciospongia digitata contained Durusdinium and Freudenthalidium. In the remaining species: Cliona sp., Cliona utricularis and Spheciospongia trincomaliensis no evidence of the presence of Symbiodiniaceae was found. Our results provide the first record of Symbiodiniaceae in the sponge genus Spheciospongia. Additionally, we provide the first findings of Freudenthalidium and first molecular evidence of Durusdinium in bioeroding sponges. Our results indicate coevolution between Spheciospongia digitata, Spheciospongia maeandrina and their symbionts. We discuss that the diversity of Symbiodiniaceae within bioeroding sponges is likely far greater than currently reported in literature. Considering the threat bioeroding sponges can pose to the health of coral reefs, it is crucial to understand Symbiodiniaceae diversity within Clionaidae and their effect on the functioning of Clionaidae species. We propose that the identity of the symbiont species is mostly related to the host species, but we did observe a potential case of environmental adaptation related to environmental stressors.

Dynamic model; the effects of eutrophication and sedimentation on the degradation of Coral Reefs in Spermonde Archipelago, Indonesia

Coral reef condition is influenced by many physical, biological, and anthropogenic processes. This research was designed to build a model between nutrient enrichment, sedimentation, and the abundance of herbivorous fish on macroalgae and coral reef coverage within the context of coral reef degradation. The research was conducted in the Spermonde Archipelago. The method used was the field survey method. The data were analyzed by using modeling instrument techniques. The results show that if there is no control over nutrient supply and sedimentation and efforts to increase the density of herbivorous fish, then the condition of coral reefs in Spermonde Archipelago is threatened with severe damage. The condition of coral reefs can be improved by decreasing nutrient supply and sedimentation of 6% each and increasing the herbivorous fish population by 5%.

Improving the quality of tridacnid clam juveniles through crossbreeding broodstock from different zones across the Spermonde Archipelago

Tridacnid clam populations have declined, and they are considered as endangered. There is increasing concern over their status in the Spermonde archipelago, South Sulawesi, where some species can no longer be found, including larger species such as Tridacna gigas and T. derasa as well as the shallow-water clam Hippopus hippopus. This research aimed to produce high-quality juvenile tridacnid clams by crossbreeding distantly related broodstock from different zones as a contribution to the effective conservation of endangered species. The research was conducted in the Spermonde archipelago and at the Hasanuddin University Marine Station Hatchery in Barrang Lompo Island. Broodstock of T derasa and T. squamosa were collected from zones III and IV of the Spermonde Archipelago. Juvenile clam production followed established methods for inducing spawning and larval rearing through trocophore, veliger, and pediveliger stages to produce juveniles that were reared in land-based and ocean nurseries. Parameters measured were the juvenile survival rate and the quality of zooxanthellae (density, chlorophyll content, and mitotic index). Data were analyzed descriptively. The mean density of zooxanthellae in juvenile clams was 3.17 x 106 cells/ind (range 3.15x106 - 5.27x106 cells/in). The mean chlorophyll-a content of these zooxanthellae was 2.7 mg/m3 (range 1.1 mg/m3 - 4.1 mg/m3), which is consistent with the mean phaeopigment concentration of 5.5 mg/m3 (range 4.2 mg/m3 - 6.2 mg/m). The mitotic index peaked at 8.5% between 09:00 and 12:00.