Underwater Visual Census Method Research Articles

Monitoring coral reef conditions in the Biorock Pemuteran rehabilitation area during the 2016 coral bleaching

Pemuteran is well-known for its community-based coral reef conservation activities utilising Biorock technology, through the application of low voltage electricity. The main objective of this research is to assess the condition of coral reefs and fish communities within the Biorock area in Pemuteran, Bali. Data collection was implemented in June 2016 at the bleaching event, employing the Point Intercept Transect (PIT) method, and the Underwater Visual Census (UVCs) method. The benthic community composition at both research stations was dominated by dead coral with algae (Biorock Pemuteran 48.9%, Menjangan Island 51%). Both research locations exhibited branching coral and massive coral as the predominant coral lifeforms. Observational findings reveal noticeable differences in the community structure of coral fish between Biorock Pemuteran and Menjangan Island waters. A total of 11,260 individuals covering 120 fish species across 21 families. Higher fish abundance in Menjangan Island (1,326 ± 224 ind/250 m2) compared to Biorock Pemuteran (551 ± 235 ind/250 m2). The condition of coral reefs at both research locations is included in the poor category (0 – 24.9%). The reef fish community in both Biorock Pemuteran and Menjangan Island is in a stable condition with low dominance level and a moderate to high diversity.

The abundance of reef fish based on ecological role and trophic level on Kaliage Island, Seribu Archipelago, DKI Jakarta

A popular tourist destination known for its colorful coral reefs is Kaliage Island, part of the Seribu Archipelago. The UVC (Underwater Visual Census) method was used in a recent study to examine reef fishes’ trophic levels, ecological roles, and community structure. Dominance, evenness, and diversity indices were used to investigate community structure. The results revealed 3,117 fish from 54 species, 16 families, and 32 genera on the reef. The two most notable species within the family Pomacentridae were Pomacentrus alexanderae and Amblyglyphidodon curacao. Fish with major, target, and indicator functions accounted for 85.98 percent, 11.29 percent, and 2.73 percent of the fish population with ecological roles, respectively. The trophic distribution of fishes revealed that 45.01 percent were omnivores, 23.10 percent were planktivores, 19.19 percent were carnivores, 9.46 percent were herbivores, and 3.24 percent were coral eaters. The analysis showed that the reef fish community was balanced and not dominated by any species, with diversity, evenness, and dominance indices of 2.53, 0.87, and 0.01, respectively. For conservation efforts throughout the Seribu Archipelago, this study provides important insights into the stability and health of the reef ecosystem on Kaliage Island.

Reef Fish Community Structure in Penyusuk Waters, Bangka Regency, Indonesia (Case Study of Artificial Reef in PT. Artha Cipta Langgeng)

Reef fishes are important components of a healthy coral ecosystem. However, when coral reefs are degraded, reef fishes also lose their habitat resulting in a decline in reef fish production and sustainable livelihood for the communities depending on it. In this study, we determined the status of reef fish communities in an artificial reef at PT Artha Cipta Langgeng in the Penyusuk waters of Bangka Regency, Indonesia. Data on reef fish communities were collected using the underwater visual census (UVC) method, including in situ and ex-situ environmental parameters. A total of 2,987 individuals belonging to 12 reef fish species and five families were recorded across three stations. The abundance of reef fish ranges from 45 to 60 ind/m², categorized as highly abundant. Diversity, evenness, and dominance indices were calculated at  1.18-1.49, 0.56-0.65, and 0.26 -0.36, respectively which are categorized as low to moderate. The environmental parameters in the artificial reef are still within the standard limit for a reef ecosystem. The study emphasizes the importance of artificial reefs as an alternative to a degraded coral reef ecosystem in supporting the thriving existence of reef fishes in the Penyusuk waters.

Temporal study of coral reef health in Kepulauan Seribu Marine National Park

Coral reefs are one of ecosystems that have high biodiversity and productivity. The condition of coral reefs in Seribu Islands is currently being threatened by various marine industry development activities. This study aims to determine coral reef health in Seribu Islands, DKI Jakarta. The study was conducted at eight observation stations in Kepulauan Seribu Marine National Park area on 7-10 March 2022 (First Monitoring) and 31 May until 3 June 2022 (Second Monitoring). Coral reef data collecting were using Underwater Photo Transect (UPT) method. Reef fish data collecting were using Underwater Visual Census (UVC) method. While for macrobenthos data collecting were using the Belt Transect method. The coral reef health index was determined based on two main components, there are benthic component and reef fish component. Overall, coral reef health from eight observation stations during two monitoring sessions had high recovery potential, although some stations had low coral cover and low target fish biomass. In addition, several species of macrobenthos are bioindicators that can contribute to purifying waters.

THE IMPACT OF SPIDER MODEL OF CORAL TRANSPLANTATION ON FISH ABUNDANCE IN THE WATERS OF BOTUTONUO, GORONTALO PROVINCE

This study aims to determine the abundance of fish in the recovery location of the coral reef ecosystem in Botutonuo waters, Gorontalo Province. The research was conducted in February - May 2023. The research location consisted of 2 sites, namely site A which had coral transplants with spider coral skeletons and site B which had no transplants (natural coral reefs). Observations were made 3 times with an interval of 2 weeks. Reef fish data was collected using the Underwater Visual Census (UVC) method, with a 50 m x 5 m line transect. Calculation of data using fish abundance rum. The results showed that the number of fish species found in the Botutonuo waters of Gorontalo Province at site A was 89 species with a total individual abundance of 2,429 ind/m2, while at site B there were 69 species with a total individual abundance of 2,054 ind/m2.

Analisis Kesehatan Terumbu Karang Berdasarkan Kelimpahan Ikan Herbivora Di Perairan Labuan Bajo

Coral reef ecosystem is one of the ecosystems located in coastal areas which has a very important role for the community, both economically and ecologically. Rock or scleractinian corals are the main building blocks of coral reef ecosystems. The connectivity of coral reef ecosystems with other ecosystems has a very large influence on the life cycle of reef fish such as spawning, rearing, foraging, and sheltering places. Herbivorous fish are that eat turf algae or macroalgae that inhibit the recruitment of new corals. Labuan Bajo is one of the tourism destinations in Indonesia, especially marine tourism. Coral reefs in Labuan Bajo cover 10.8% of the total area of coral reefs in Indonesia located in Nusa Tenggara. The purpose of this study was to determine the health of coral reefs in the waters of Labuan Bajo. This research will be carried out from September to October 2021. The coral reef data collection method used is the Underwater Photo Transect (UPT), and for reef fish is using the Underwater Visual Census (UVC) method. Based on the research results, the percentage of hard coral is 20.16% of the total stations and rubble is 32.24%. The abundance of fish in Labuan Bajo waters ranges from 1608.89 - 4600.00 ind/ha, where the average abundance is 2919.78 ind/ha. All stations got a health index value of 3, this is indicated by the low coral cover, high coral resilience, and low herbivorous fish biomass obtained.

Zoning Effectiveness of Marine Nature Reserve Conservation Areas (SAP) Raja Ampat Islands Against Coral Reef Protection

Raja Ampat Islands have been designated as a Marine Nature Reserve (SAP) since 2014, and community activity in these waters remains high for tourism, fishing and sea transportation activities. All of these activities have the potential to suppress the condition of the coral reefs there. Therefore, it is necessary to evaluate the effectiveness of zoning in terms of social and ecological indicators. This research was conducted using the Underwater Visual Census (UVC) method for coral reef fish and the Underwater Photo Transect (UPT) method for coral cover at a depth of 5-7 m. The set critical threshold value is used to evaluate the success of the zoning taken by interviewing fishermen. The results of the study found that the core zone had unfavorable conditions compared to the other zones. Based on an analysis of ecological indicators, the percentage of coral cover was only 20.9% and an abundance of reef fish of 28 ind/m2. The results of the social analysis of the community, Waisilip Village has the lowest level of compliance with a value of 56%. Meanwhile, 77% of respondents agree with zoning, and only 19% understand the zoning management system. The management of SAP Raja Ampat can be said to be effective by taking into the ecological and social indicators of the community. Increase in the percentage of coral cover in the core zone (0.2%), utilization zone (3.9%), sustainable fisheries zone (0.8%) and cultivation zone (5.7%). Most fishermen have good insight and concern for coral reefs and other aquatic resources.

The condition of megabenthos and reef fish in coral reef ecosystems in Aru Islands National Conservation Area, Southeast Maluku, Indonesia

The waters of the Aru Islands are part of the National Marine Protected Areas (MNR), and have extensive coral reefs with high biodiversity. The study was conducted in October 2016 at twelve stations to determine the status of coral cover, composition, and density of megabenthos and reef fishes. Coral reef data collection refers to the Underwater Photo Transect (UPT), and data processing uses Coral Point Count for Excel (CPCe). The Benthos Belt Transect (BBT) method was used for megabenthos data, and the Underwater Visual Census (UVC) method was used for reef fish observations.The result of the benthic component analysis showed that the proportion of live corals at each station ranged from 10.60% to 54.27%, with an average cover value of 31.21%, which fell into the “fairly good” category. Megabenthos density analysis revealed that Drupella cornus had the highest density value (0.29 individuals/m2) and Holohuria edulis (0.01 individuals/m2) had the lowest density. Analysis of the reef fish community revealed that the indicator fish were 168 individuals from the family Chaetodontidae. The group of herbivore fish recorded 116 individuals from threee families: Acanthuridae, Scaridae, and Siganidae. Acanthurus auranticavus and Acanthurus pyroferus are common species found in the waters of the Aru Islands.

The Assemblage of Carnivore Fish Composition (Lutjanidae, Lethrinidae, Haemulidae and Serranidae) of a Thousand Islands, Jakarta, Indonesia

The pivotal contribution of the Lutjanidae, Lethrinidae, and Serranidae families to coral reef ecosystems, coupled with their significance as targets for fishing activities, underscores the importance of understanding their presence and population dynamics in formulating effective coastal management policies. Employing the Underwater Visual Census (UVC) method, we conducted a carnivorous fish study at 14 station locations in the Thousand Islands. This group exhibited a diverse array of 17 species distributed across four families (Haemulidae, Lethrinidae, Lutjanidae, and Serranidae). Notably, Cephalopolis micropion emerged as the predominant carnivorous species, constituting 48.35% of the relative frequency. Site location KSBC.14 (Pari Island) displayed the highest diversity and abundance of carnivorous fish species, with 11 species and 1457 individuals per hectare (Ind./ha). KSBC.12 (Pramuka Island) also have highest abundance and additionally recorded the highest carnivorous fish biomass at 188.43 kg/ha. These findings provide valuable insights into the ecological dynamics of carnivorous fish populations, informing conservation and management strategies in coral reef ecosystems.

Impact of Coral Bleaching on Coral Reef Fishes in Sekotong Bay, West Lombok Regency

Coral reef fish is one of the main components making up the ecosystem of coral reefs. There is a strong mutual dependence between reef-forming corals and fish that inhabit coral reefs. Various fish species use coral as a food source and habitat. This article describes the impact of coral bleaching on the diversity, density, and biomass of coral reef fish in the waters of Sekotong Bay, West Lombok. Underwater visual census (UVC) methods are used to obtain data on species, the number of individuals per species, and fish size at transect length 70 meters and width 5 meters. Simple linear regression analysis that is used to assess the impact of coral bleaching on the condition of coral reef fish shows that coral bleaching affects the diversity and density of reef fish. This analysis also showed that coral bleaching affected herbivorous fish biomass but not carnivorous fish. This study concludes that the degradation of coral fish in the Sekotong Bay of West Lombok occurs due to various factors, especially the declining health conditions of coral reefs

Comparison of Underwater Visual Census (UVC), Underwater Remote Video (RUV), and Handline Used by Fisheries-Independent Programs to Assess Reef Fish

Fisheries managers rely on independent programs to collect data to design and inform management plans and decisions. These programs aim to implement cost-effective, robust monitoring approaches to assess spatiotemporal changes in fish structure and composition using different methods, which could lead to different conclusions. We compared four methods: two types of underwater visual censuses (UVC) (i.e. transect and roving), remote underwater video (RUV), and fishing using handline (HL) to characterize differences, identify potential complementarities, and estimate relative precision among them. All methods were simultaneously performed on 13 sites in Fajardo, eastern Puerto Rico for a total of 26 visits, and nine sites in La Parguera Natural Reserve (LPNR), western Puerto Rico for a total of 43 visits. Multivariate analysis revealed significant dissimilarities between all methods, with higher species diversity, abundances, and biomass observed in UVC and RUV. Patterns of spatial and temporal variation detected with UVC and RUV were significantly correlated among them, but not with HL. Univariate analysis for commercially important species showed that UVC and RUV methods were more precise and time efficient than HL. Complementarity between UVC and RUV was observed with the latter increasing the diversity observed during surveys. This study showed that UVC and RUV were different, however, they can be used complementarily they were significantly correlated. HL should be used when additional information (e.g. sex and age) is needed. A multi-gear approach with increased use in RUVs is recommended depending on the aims of the study to precisely assess a broader diversity.

Biak and Wakatobi reefs are the two hottest hotspots of coral reef fish diversity and abundance in the Indonesian Archipelago

The Indonesian Archipelago has a very complex geological history, along with equatorial warm sea temperature, resulting in diverse types of coral reefs and high diversity of coral reef fish. Many livelihoods of the coastal community are dependent on coral reef fisheries. The present study aimed to determine which region and location in the Indonesian Archipelago has the most diverse and abundant coral reef fish. The archipelago was divided into four regions: the Indian Ocean, Sunda Shelf, Wallacea, and the Pacific Ocean. Data were obtained from a national coral reef monitoring program of the Indonesian Research Center for Oceanography (RCO)-the National Board for Research and Innovation (BRIN). The reef fish data were collected using the underwater visual census method, from 321 belt transects on 24 locations (districts) across the archipelago. The results show that coral reef fish diversity of the Pacific region was the highest across the archipelago for all three trophic levels, i.e., corallivore, herbivore, and carnivore fish. The Pacific Ocean region also had the highest fish abundance for the three trophic levels. Comparison among locations revealed that the best ten locations in reef fish diversity and abundance were Sabang, Mentawai, Makassar, Selayar, Buton, Luwuk, Ternate, Raja Ampat, Biak, and Wakatobi. Wakatobi reefs showed their supremacy in carnivore fish diversity and abundance, while Biak reefs were the best in herbivore fish. The abundance of corallivore fish was also considerably high in Sabang reefs, but it is still lower than in Raja Ampat, Biak, and Wakatobi reefs. These results provide empirical evidence that the coral reefs of Wakatobi and Biak are the hottest hotspots of coral reef fish diversity and abundance in the Indonesian Archipelago.

Kelimpahan Ikan Karang Famili Chaetodontidae dan Kondisi Terumbu Karang di Perairan Pulau Talam, Tapanuli Tengah

The Chaetodontidae family fish is an indicator species because it has a close relationship with coral reefs based on a strong preference for coral stone as the main component of coral reefs. The existence of these fish can be used as a guide to assess and monitor the condition of coral reefs. This study was conducted in March 2022. The purpose of this study was to determine the abundance of reef fish of the Chaetodontidae family in the waters of Talam Island, to determine the condition of life coral cover and the relationship between the abundance of the Chaetodontidae family and coral cover. The method used in this study is a survey method. Data collection on reef fish of chaetodontidae family was carried out using the Underwater Visual Census (UVC) method and coral reefs condition data collection was done using the Line Intercept Transect (LIT) method. The results showed that the abundance of Chaetodontidae ranged from 710 to 1,430 individuals/ha with an average of 1,110 individuals/ha. The highest abundance of 1,430 individuals/ha at station III with a depth of 6 meters, while the lowest abundance was station II with a depth of 8 meters which was 710 individuals/ha. The percentage of life coral cover at each station ranged from 47.70% - 56.98%, 42.60% - 54.40% and 56.68% - 69.08%. Based on these percentages, the average percentage of life coral cover is 54.74% (good category), and there is a very strong relationship between life coral cover and the abundance of the Chaetodontidae family.

Reef Fish Diversity in Jayapura City, Indonesia: A Preliminary Study

As one of the marine areas included in the world's Coral Triangle region, Yos Sudarso Bay have a potential reef fish diversity that needs to be studied. However, there is very little information about reef fish diversity in these waters to date. This study aims to determine the species diversity of reef fish in Yos Sudarso Bay, Jayapura City, Indonesia. The study was conducted in April 2020 at seven sites; six of them located inside the Yos Sudarso Bay and one more located outside the bay. Sampling was carried out using the Underwater Visual Census method (25 m long and 5 m wide). Relative abundance by species, and diversity (H´), evenness (E), and dominance (C) indices were calculated. A total of 1,075 individual reef fish was recorded in seven study sites, representing 122 species and 26 families. Locations showed differences in reef fish abundance (86 to 215 individuals/125 m2), diversity (H´= 2.462 to 3.358), evenness (E = 0.770 to 0.887), and dominance (C = 0.047 to 0.155). This study has provided preliminary information on species diversity, fish abundance, and the ecological index of reef fish in Yos Sudarso Bay, Jayapura City. 

Komposisi dan Struktur Komunitas Ikan Kepe-Kepe (Chaetodontidae) di Teluk Paraja, Kabupaten Pandeglang, Banten

Fish that spend most of their life cycle and depend on the existence of coral reef ecosystems arereef fish. Butterflyfish (Chaetodontidae) is a family of fish that can live in association with coral reefs and has an important role in coral reef ecosystems, causing butterflyfish to be very sensitive to changes in coral reef conditions. The tsunami in Paraja Bay, Pandeglang Regency, Banten, in December 2018 made a difference in habitat conditions. This significant difference can affect the abundance of fish that live in it, especially butterflyfish. The availability of data onthe community structure of reef fish in Paraja Bay is categorized as "poor data". Therefore, this study was conducted to add more specific data regarding the abundance and community structure of reef fish from the Chaetodontidae family. This research was conducted in February 2022 using the Underwater Visual Census (UVC) method to collect fish data. Data were taken on each side of the four small islands for 16 stations. The depth of the observation station is between 5-6 m. Observations at each station were carried out by placing a 50 m roll meter parallel to the shoreline with a width of 2.5 meters to the right and 2.5 meters to the left, and 5 meters above the roll meter. The result shows that there were 179 individuals found from 4 genera and 14 species of the Chaetodontidae. The species found were Chaetodon collare, C. Kleinii, C. ephippium, C. octofasciatuus, C. rafflesia, C. trifasciatus, C. vagabundus, Chelmon rostratus, Forcipiger longirostris, Heniochus acuminatus, H. pleurataenia, H. singularis, and H. singularis, H. varius. The community structure was analyzed using fish abundance, diversity (H'), dominance (C), and evenness index (E). The highest abundance of butterflyfish was 0.09 ind./m2, and the lowest was on the east side of Oar Island, which was 0.00 ind./m2. The butterflyfish diversity index ranged from 0,61 (Umang Island) to 0.71 (Badul and Mangir Island). The fish evenness index ranged from 0.69-0.84, where the highest value was 0.84 on Mangir Island and the lowest was 0.69 on Oar Island. The highest dominance index has a value of 0.35 on Oar Island, while the lowest is on Mangir Island, with a dominance index of 0.25. Based on these results, we can conclude that the genus Chaetodon has the most significant composition. Based on the community structure result, Paraja Bay’s waters provide equal opportunities for all species but have low species variation. Each species has a small number.  It can be known that it is necessary to conserve and maintain coral reef ecosystems to increase the abundance and presence of butterflyfish in the waters of Paraja Bay, Pandeglang, and Banten.

Environmental DNA biomonitoring reveals seasonal patterns in coral reef fish community structure

Coral reef fish populations are declining due to multiple factors including habitat destruction, overfishing, and climate change. While these can include seasonal impact, seasonal changes can also be a confounding factor, so that seasonal monitoring is essential for detecting true temporal changes in fish community abundance and composition. However, seasonal monitoring is rarely implemented. The aim of this study was to detect the seasonal patterns of coral reef fish community structure around Tidung Kecil Island, Indonesia, using eDNA metabarcoding (eDNA) and underwater visual census (UVC). The UVC identified 32 species belonging to 10 families in the rainy season and 29 species belonging to 7 families in the dry seasons. The eDNA metabarcoding identified 209 species belonging to 56 families and 27 species belonging to 17 families in the rainy and dry seasons, respectively. Based on eDNA metabarcoding data, coral reef fish abundance and community composition differed significantly between seasons (Mann Whitney, p < 0.01), while the UVC method did not detect these seasonal differences (Mann Whitney, p > 0.05). UVC and eDNA data both showed a predominance of omnivorous fishes in the rainy season and carnivorous fishes in the dry season. Ecological indices did not differ significantly between seasons for the two used methods, although the species making the highest contributions to the similarity (SIMPER) analysis differed between methods. Overall, this study confirms the premise that eDNA metabarcoding can be an effective tool for monitoring seasonal variation in coral reef fish communities.

Coral reefs recovery post bleaching event in Central Tapanuli, North Sumatra

Temperatures on the west coast of Sumatra, South Java, Bali, and Nusa Tenggara in the Indian Ocean rose dramatically in 2016. The extreme increase in temperature greatly affects sea surface temperature and coral reef ecosystems. Central Tapanuli waters were also the area that could not escape this phenomenon. Coral bleaching has caused damage to coral reefs which is characterized by decreasing live coral’s cover. Observations on coral reef recovery have been carried out at 13 sites in Central Tapanuli waters. Observations were made using the UPT (Underwater Photo Transect) method to determine live coral’s cover. The coral fish density was determined using the UVC (Underwater Visual Census) method. From the observations, coral cover decreased by 57,68% in 2016. Observations were made in 2015, 2016, 2018, and 2021. Observations in 2018 have shown increasing live coral cover by approximately 5%. Meanwhile, in 2021 there was an increase in live coral cover by approximately 8.25% from 2018. Even though coral composition changes and mostly the number of coral decreases, after 5 years, the number of corals starts to increase. The reef health index likewise rises in tandem with these changes. Despite some chronic stress being present at some places, the water quality was favorable for coral recovery.

Analysis of coral reef diversity and its correlation to fish abundance in Biawak Island cluster areas

The importance of coral reefs for humans and marine biota must be conserved due to threat of climate change and anthropogenic pressures, one of which is in a cluster of small islands in Indramayu Regency, (comprising Biawak, Candikian and Gosong island). This study aims to assess the status of coral reefs in Indramayu (percent cover, diversity, uniformity, and dominancy of the coral reef ecosystem) as well as the potential correlation with fish abundance. Areas of interest were pre-determined using Lyzenga method, ground truth using the LIT (Line Intercept Transect), while genus-based fish abundance using UVC (Underwater Visual Census) method. This study revealed that the status of coral reefs is in moderate condition. The diversity index ranges from 1 to 3, and dominancy index is less than 0.50, indicating a stable reef community where no dominant genus is found in the community. The correlation between fish abundance and the live coral cover percentage showed a positive linear association. These results indicate that current coral reef ecosystems seem unaffected by anthropogenic pressures. It is expected that these results can be used by local authorities to conserve coral reef ecosystems and marine biota, and to maintain the sustainability of community livelihoods.

Development of Diving and Snorkeling Ecotourism Based on Natural Resources Potential of on Miang Island Kutai Timur Regency

Miang Island has potential coral reef resources that can be used for marine ecotourism of diving and snorkeling, but there has not been any related study yet. This study aims to analyze the condition of coral reef resources, analyze the suitability and carrying capacity of the area for ecotourism and develop a strategy for developing diving and snorkeling ecotourism on Miang Island. The method being used for coral reef data collection by Underwater Photo Transect and reef fish using the Underwater Visual Census method. To develop the strategy of developing ecotourism is analyzed by using the Interpretative Structural Modeling (ISM) method. The results showed that the condition of coral reefs on Miang Island was in the moderate category with 40% live coral coverage. The area that can be used for snorkeling tours is 24.39 ha with a carrying capacity of 976 tourist visits/day. Meanwhile, the area that can be used for diving tourism is 13.40 ha with the ability to receive visitation of 536 tourist visits/day. Based on these conditions, the ecotourism development strategy is formulated that protects and utilizes coral reef ecosystems as sustainable tourism objects, facilitates access to development capital, makes a consistent policy, and coordinates between related agencies.

Preliminary Assessment of Invasive Lionfish Pterois miles Using Underwater Visual Census Method in the Northeastern Mediterranean

Abstract Underwater visual census (UVC) is a commonly used approach for assessing fish density and biomass. Iskenderun Bay, comprising the Samandağ coast in Turkey, is the most important introduction pathway of alien species in the northeastern Mediterranean. In this study, the density, abundance, distribution and interaction of invasive lionfish or devil firefish Pterois miles were assessed using the UVC method on the Samandağ coast. The total transect area monitored on the Samandağ coast was 4.500 m2. Species richness, Shannon’s diversity index and rate of biomass were 25, 1.81 and 73.5 m2, respectively. Reduced diversity was observed with increasing depths. The sandy seafloor was a limiting factor for lionfish distribution. There was a significant positive correlation between lionfish total density and both the Shannon diversity index (r = 0.99, P&lt;0.001) and Shannon evenness index (r = 0.99, P&lt;0.05). A high number of significant positive correlations (P&lt;0.05) were detected between the occurrence of lionfish and the occurrence of both the native species and other alien species. The first stock assessment study of lionfish by the UVC method in Turkish marine waters revealed that native species are under very high pressure from lionfish species, especially Chromis, Sparids and Wrasses, indicating negative effects of lionfish on regional native biodiversity.