Location assessment for coral reef transplantation program in Karawang Waters, Indonesia

Environmental degradation caused by anthropogenic activities and climate change has an impact on the habitat of organisms and biodiversity. Coral reefs are one of the sensitive ecosystems that are strongly influenced by environmental changes. Poor environmental conditions in the Java Sea and global warming are the main factors that affect the sustainability of coral reef ecosystems in Karawang waters. Coral reef transplantation is a method that has long been used to revitalize coral reef ecosystems. This study aims to assess the ideal location used for coral reef transplantation program in Karawang Waters. Through a field survey, the percentage of coral reef cover, dead coral, hard coral, algae, and biotic and abiotic components at several sampling points in 2019 to 2022 was obtained. The sampling location with the poor conditions are considered to be used as transplant locations. Based on analysis result, only 1 out of 3 locations that are suitable to be used as locations for coral reef transplantation programs.


Introduction
One of the marine ecosystems found on the shore and in the sea, particularly in tropical areas, is the coral reef environment.Coral reef-constructing organisms consisting of lime or CaCO3 are the dominant species in this habitat.Coral animals (Scleractinia), which are symbiotic with zooxanthellae algae, assist clean corals of debris and supply extra nutrients in the form of acids.[1].In addition, coral reefs can generally be found in fairly warm waters with sea water temperatures above 20 °C [2].Coral reefs have a fairly slow growth depending on the type.In rocky or massive corals, it can grow up to 2 cm per year.However, the branched species (Acropora) can grow up to 5-10 cm per year.Moreover, the growth of coral reefs is also influenced by environmental conditions such as sedimentation rates, light intensity and substances contained in the sea water [3].
Coral reefs are one of the marine ecosystems that are rich in biodiversity, which has enormous benefits in the fisheries sector.They form unique ecosystem and source of nutrients for marine life [2].As one of the ecosystems in coastal areas and also spread over small islands, coral reefs function as a spawning ground, nursery ground and feeding ground for most fish [4].The high productivity of 1260 (2023) 012019 IOP Publishing doi:10.1088/1755-1315/1260/1/012019 2 fisheries (reef fish) which have high economic value indicates that coral reefs provide a direct contribution to the fisheries sector.
Coral reef ecosystems are very vulnerable to disturbances that can cause health decline and damage to ecosystems.The decline in the health of coral reef ecosystems can be seen from bleaching process, coral fractures, and decline percentage of coral coverage [5].Disturbing factors for coral reef ecosystems include anthropogenic activities such as destructive fishing, excessive fishing activities (overfishing), water pollution from both domestic and industrial waste, excessive flow of nutrients, recreational activities, unsustainable development both on land and on the coast such as beach reclamation [6].
The high risk of damage to coral reefs due to natural and anthropogenic factors can damage ecosystems and the food chain balance in the sea considering that coral reefs are a habitat for marine animals.Based on this, the coral reefs restoration and rehabilitation program needs to be pursued [4].Generally, there are several methods commonly used for coral reef restoration, such as transplantation, larval enhancement, coral gardening, substrate addition, substrate stabilization, etc. [7].Various restoration methods have their own advantages and disadvantages.The selection of restoration methods can be adapted to environmental conditions and the availability of funds from the restoration program [8].
Karawang waters have a variety of potential marine ecosystems including coral reef ecosystems.The area of coral reefs in Karawang waters in 2001-2017 showed a significant decrease [9].The existence of environmental degradation caused by natural and anthropogenic factors in this area has caused a lot of damage to the coral reef ecosystem and is threatened with extinction.Based on these problems, various stakeholders from local governments, companies, universities, and local community are trying to conserve coral reefs in Karawang Waters [9].This study aimed to see the condition of coral reefs in several areas in Karawang Waters and to assess coral reef transplantation sites based on these conditions.

Study location
The study site is located in Tangkolak Hamlet, Sukakerta Village, Cilamaya Wetan District, Karawang Regency, West Java Province, Indonesia (Figure 1).This research was conducted in 3 locations with coral reef potential in Karawang Waters (Table 1).The overall location of these coral cluster is 2 -4 miles from the coastline in Karawang Regency.

Data collecting
Data was collected by using Line Intercept Transect (LIT).This method was selected because it can provide more accurate results in estimating coral coverage [10].Percentage cover of hard coral, soft coral, sponges, algae, rock, and dead coral aggregate several benthic communities [11].Data collection was carried out in August 2019 and May 2021.Coral reefs observations were made using an underwater camera.To find out total area of coral reefs, observation was carried out to identify the ecosystem which is in good or damaged condition.Furthermore, to observe in detail, observations were made using the transect method.Data collection was carried out by using 50-meter transect lines.

Data analysis
Data analysis was carried out using coral reef observation guidelines referring to Minister of Environment Decree No. 4 of 2001 concerning the standard criteria for coral reef damage (Table 2).Areas with decreased coral reef cover can be an important consideration for coral reef transplantation sites [12].Source: [13] Seawater quality data was carried out based on reference to the Government Regulation of the Republic of Indonesia No 22 of 2021 concerning implementation of environmental protection and management criteria for coral (Table 3).Depth m -Source: [14] The determination of the location for coral reef transplantation activities is also adjusted to the government regulation, RZWP3K.The zoning plan for coastal areas and small islands (RZWP3K) is one of the instruments in controlling the use of marine space which is under the authority of the provincial government.RZWP3K itself as a development directive which is legalized in a Regional Regulation.This zoning is used to determine the direction of resource use for each planning unit accompanied by the determination of the structure and spatial pattern in the planning area which contains activities that may and may not be carried out and activities that can only be carried out after obtaining permits in coastal and island areas.

Coral reef ecosystem
Generally, the types of coral reefs in Karawang waters are categorized into patchy types.The coral reef areas that have been observed were at a depth of less than 6 meters, however, they have very low visibility, especially at the bottom of the water column.Visibility in the water is very limited at 0.5 -2 meters.Karawang waters was relatively turbid since many tributaries of the Citarum River that flow into Karawang Waters [15].The river flows by carrying a lot of silt that comes from irrigating rice fields in Karawang Regency.Beside silt and Total Suspended Solid (TSS), this river of course also carries a lot of fertilizer residue from rice fields and other domestic waste [16].This residue can add turbidity that lasts a long time, also causes the proliferation of biota such as sea urchins and algae that are often found on coral reefs during the survey [17].
Based on the survey results of coral reef cover conditions in 3 locations in 2019 and 2021, the dynamics of the percentage of coral reef cover were obtained which consisted of hard coral, death coral, algae, other biota, and abiotic components.In 2 years, the result showed a decrease in conditions in 2 locations, Karang Sendulang and Karang Bengkok.Meanwhile, at Karang Bandengan condition is categorized as stable.Based on Table 4, it can be seen that the coral cover condition as a result of the survey is in the damaged-moderate to damage-poor category according to the Minister of Environment Decree No. 4 of 2001 concerning Standard Criteria for Coral Reef Damage [13].If transplantation is not carried out immediately, the coral cover in the Karawang waters will decrease.Tabulation of coral reef survey results in Karawang waters is presented in Figure 2.There was a decrease in the percentage of hard coral area in 2 locations, Karang Sendulang (17%) and Karang Bengkok (19%).This decrease occurred significantly due to the damage conducted by the surrounding community.The coral reefs selling and exporting has increased the exploitation of coral reef ecosystems in Karawang Waters.Damage to coral reefs in Karawang waters has been recorded since the beginning of 2010, the damage was caused by anthropogenic activities such as ornamental corals theft for export commodities [9].These areas also experienced overfishing activities through the use fishing gear that is not environmentally friendly such as Muroami, bubu tambun, and toxic material such as potassium cyanide [18].In Karawang, there is a tendency to decline in the production of catch fisheries and lack of governance that are incompatible with responsible management principles [19].This area was targeted area for crab trap fishing gear, hand fishing rods and others where the use of boat anchors has contributed a lot in degrading coral reef cover.On the other hand, there was an increase in the area of hard coral in Karang Bandengan by 8%.
Based on survey data in 2021, no dead coral was found.This also confirms that the decrease in the percentage of hard coral cover is not caused by the death of coral reefs but by the practice of theft carried out by the community.Based on the survey results, in the last 2 years, coral mortality has decreased to 0% (Figure 3).The increase of algae percentage is inversely proportional to the growth of hard corals.The higher decline in hard coral in a location, the higher the algae growth will be (Figure 4).This is due to the higher algae growth on the substrate that is not occupied by hard corals.The role of algae in coral reef ecosystems is like a succession or pioneer plants when the percentage of coral reef cover experiences drastic decrease.Macroalgae have replaced reef-building corals as the dominant habitat former [4].In general, the dead corals found have been overgrown with turf algae, algae assemblege, or coralline algae.Some dead corals have even been categorized as abiotic such as coral rubble or rock.The most abundant abiotic components found in almost all observation sites are rock and sand (Figure 5).There are other abiotic components such as coral fractures.The decrease in abiotic components occurs in areas that are often exploited by the surrounding community [20].This is because people often use coral fractures to be used as aquascape decorations.In 2019, in Karang Sendulang, abiotic components tend to be more dominant than hard corals due to the high TSS.High TSS in a water causes a lack of light penetration and a high deposition rate so that coral reef polyps are covered [21].This condition can eventually lead to the death of coral reefs, thus causing a change from the dominant coral phase to being abiotic dominant in the coral reef ecosystem.The abiotic components that are often found at the observation site are rock, sand, coral fractures, and silt.
Based on the growth form, stony corals (scleractinian) are divided into Acropora and non-Acropora corals [3].The difference between Acropora and non-Acropora lies in their skeleton structure.Acropora has parts called axial corallite and radial corallite, while non-Acropora only has radial corallite.Coral reef ecosystems in the three locations only have non-acropora life forms consisting of branching corals, encrusting corals, foliose corals, and massive corals.Based on Table 5, most of observation points dominated by the massive coral.The highest coral encrusting category were found in Karang Bengkok.
The dominance of massive coral at all observation sites illustrates that this location has quite high ecological pressure, especially from water conditions that are often turbid, with very low (poor) visibility.In such conditions, only massive coral species are usually better able to survive with long life expectancy [22].Compared with non-acropora, acropora corals have fast growth but are vulnerable to stressors from anthropogenic factors.This is the trigger of acropora life form loss at the observation site.From the three locations, Karang Sendulang has the lowest frequency of life form occurrence.

Coral reef transplantation
Coral reef transplantation is one of the commonly used methods for coral reef restoration because the price is quite affordable and easy to apply [23].This method is conducted by attaching coral reef fragments to an object or object in the sea so that coral animals can grow back.Objects that are attached to or tied to these coral animals can be concrete, pipes, iron and other objects that can sink in the sea.This transplant method aims to accelerate the return of coral cover and biodiversity that has been damaged by human activities and natural factors [24].This method can also be influenced by natural conditions.If the original location of the coral reef does not have good enough water quality, it is better to move the transplantation location.So that the coral reefs can survive the return to the location where rehabilitation is carried out.Artificial coral reefs have been used for more than 200 years to increase fish catches [7].Based on several parameters, data on sea water quality in Karawang waters is not suitable for marine life due to low clarity and high TSS (Table 6).However, the potential for existing coral reefs confirms that there are coral reefs that are able to adapt to environmental conditions with high stressors.To obtain restoration results with a high success rate, several supporting factors are needed such as adequate funding, long-term monitoring, and accurate site assessment.To avoid damage to coral reefs after the restoration program has started, stressors on restored sites need to be removed [23].In addition, the presence of hard substrates and low presence of hard corals, sponges, or soft corals are also ideal locations for the growth of transplanted corals [25] In recent years, several anthropogenic factors of coral reef damage in Karawang Waters have been minimized.The existence of strict monitoring of the exploitation of coral reefs and overfishing has been carried out by the local government with the assistance of community organizations.In addition, since the Citarum Harum program implemented by the central government in 2018, the water quality of the Citarum River has begun to improve [26].This can have a positive impact on ecosystem conditions in Karawang Waters which is the estuary of the Citarum River.
In 2022, the Karawang Regency Government through the Karawang Regency Fisheries Service will collaborate with various stakeholders consisting of oil and gas companies, universities, and community groups to create a coral reef restoration program in Karawang Waters.This program is based on the desire to restore the coral reef ecosystem in this area as before.The existence of strict supervision of exploitation activities is not enough to preserve the ecosystem.Therefore, transplantation program was chosen as coral reef restoration method in this region.

Location assessment
Several parameters can be used as criteria to determine the suitability of biophysical conditions for coral reef growth.Some of these parameters include depth, water clarity, water turbidity, temperature, salinity, current speed, waves, basic substrate type, reef exposure, protection, rock cover, and the distance from coral seed sources [27].However, in this study, the determination of the ideal location for coral transplantation uses simpler criteria, such as a decrease in the percentage of hard coral, the low occurrence of life forms, and the suitability of the location with the RZWP3K area.
One of the criteria used to choose the site was areas with a decline in the percentage of hard coral.In order to restore coral reef ecosystems, conservation efforts are urgently needed where coral reef ecosystems are declining.The low appearance of hard coral life form is also a factor in site selection.Sites with a low frequency of living forms will be given consideration for selection as transplant locations.In addition, RZWP3K becomes an important factor.The area that can be used as a transplant location should not be included in the utilization of oil and gas exploration area.Oil and gas exploration areas will pose a threat to the sustainability of the transplant program that will be implemented.
Utilization of space in water areas is regulated in coastal zone zoning which is adjusted to the potential of resources and carrying capacity as well as ongoing ecological processes.Water zoning in Sukakerta Village has also been regulated in the RZWP3K in West Java Province for 2019-2039 which was ratified based on Regional Regulation No. 5 of 2019.Based on the allocation of space, the waters of Sukakerta Village, especially Karang Sendulang, are designated as a Maritime Conservation Area (KK-KKM-02) with a strategy to secure conservation areas includes enrichment of natural resources, habitat improvement, protection of marine biota species so that they grow and develop naturally, and apply environmentally friendly methods (Figure 6).Based on these three criteria, the tabulation of transplant site selection can be seen in Table 7.Based on the Table 6, Karang Sendulang is an area that meets these three criteria.The poor condition of coral reefs in the area is a driving factor for restoration activities at this location [9].On the other hand, the government and community groups have implemented strict supervision to remove threats and disturbances to the coral reef ecosystem in this region [20].The elimination of pressure in restoration area is a major factor in the success of a restoration program [8].Karawang waters are rich in oil and gas potential.This condition makes several locations with high coral reef potential unable to be ideal restoration areas.Karang Sendulang is not included in the oil and gas exploration area so that transplant activities can be carried out in this area without worrying about being damaged due to exploration activities.

Conclusions
The condition of coral reef ecosystems in Karawang Waters has decreased during 2019-2021.This decrease was caused by various factors, both anthropogenic and natural factors.The theft of coral reefs by local communities is the main factor in the decline in the percentage of hard corals in this area.Bad

Table 2 .
Category of coral reef conditions.

Table 3 .
Seawater quality standards for coral.

Table 4 .
Observation data in 2019 and 2021.

Table 5 .
Frequency of the existence of coral reef life form.

Table 7 .
Criteria of location assessment for coral reef transplantation.