Identification of land suitability as the basis for cultivation of octopus cyanea in Lombok waters

. Octopus has an important ecological role as both a predator and prey and is classified as an important economic fishery commodity because it contains high enough nutrition. Octopus is germplasm which is Indonesia's wealth of biological resources. The existence of this octopus needs to be maintained in these waters so that its sustainability is maintained. Therefore, it is necessary to manage octopus cultivation considering the importance of octopus economic and ecological functions. Geographic information system is one method that can be used in this research. This method can be used to make it easier to find out the location of its distribution, so that the development of octopus cultivation activities can be achieved optimally. The purpose of this study was to analyze the prospects for octopus cultivation using GIS applications presented in the form of supply maps for octopus cultivation in the Lombok waters. This research was conducted in June - July 2023 and the determination of sampling locations was carried out using purposive sampling based on consideration of problems with environmental conditions at the observation station, covering the Lembar area, Beraringan Beach, Ketapang Beach, Sari Gong Beach and Poto Tano. The results obtained are: temperature 25,25 – 38,13 0 C, brightness 20 - 25 m, current speed 0,2 – 0,8 m/s, depth 20 - 25 m, rainfall 65 - 364 mm, protection: protected, sufficient protected and unprotected, pH 5,7 – 8,4 salinity 33 – 37 ppt, DO 6,19 – 6,52 mg/l, substrate: sandy coral, coral fracture and rocky coral, chlorophyll a 0,26-1,38 mg /m 3 , and the number of octopuses 100 - 250 individuals. Locations according to land for very


Introduction
Cephalopods are one of the potential commodities that live in Indonesian waters, with an estimated 100 species and 24 of which are local types of Indonesian waters [1].Octopus has an important ecological role as a predator and is classified as an important economic fishery commodity because it contains high enough nutrition and ranks third in the world of fisheries after fish and shrimp.Octopuses belong to the cephalopod class and are animals that live in almost all seas, from tropical seas to the north and south poles [2].
Until now, cephalopod fisheries, especially octopuses, have not been studied much either because they receive less attention in the field of production and the factors that influence the management of octopus fisheries [3].Therefore, information about the spatial distribution is needed in order to more easily know the location of its distribution, so that development in octopus cultivation activities can be achieved optimally.
The purpose of this study was to obtain data and information regarding the identification of characteristics of waters suitable for Octopus cyanea octopus cultivation using GIS applications in Lombok waters.The results of this study are also expected to be able to formulate the concept of sustainable octopus management.This research provides an update in the development of management concepts as a scientific basis for sustainable management of octopuses so that they can contribute knowledge to researchers and cultivators.

Research Methods
The research locations are Lembar Beach, Beraringan Beach, Ketapang Beach, Sari Gong Beach and Poto Tano.The research was conducted in June -July 2023 covering the collection of the necessary data and direct sampling from the three locations.The coordinates can be seen in Table 1.
Survey quantitative research method is the method used in this study, namely from the background of the problem, problem identification, problem formulation and field data collection regarding the condition of sea waters and the data obtained was analyzed using ArcGIS 10.8.
The tools used are small boats, sample containers, tide boards, pH meters, thermometers, stopwatches, cameras, ropes, GPS, refractometers, pH, DO meters and secchi disks.The materials used are octopus, tissue and label paper.

Research Procedure
The research area was carried out in Lombok waters.Lombok Waters Digital Data is used as a base map for making thematic maps, then interpolation is carried out for each parameter.
The water conditions to be measured are: temperature, brightness, depth, current velocity, rainfall, pH, salinity, DO, chlorophyll a, substrate, and octopus biomass.Then a contour map is made from the primary data for each parameter as a background for the digitization process so that each thematic map is divided into several classes.Furthermore, the water condition map or contour map is analyzed by overlay, which is an overlapping analysis that combines information from several maps to produce a new information that has been built previously with criteria or parameters.After the criteria have been developed and analyzed, a map of the suitability of the octopus cultivation area will eventually be produced.Figure 1 shows map of research locations.[10] 29 -33 24 -32 <23 or >36

Results And Discussion
The results of research conducted by collecting in situ data and through observing data from remote sensing satellites show that there are differences at each point of the observed research location.The difference in points is then adjusted to the quality standards of each parameter.The use of quality standard parameters determines the level of land requirement for clam cultivation.Rainfall data was obtained from the BMKG Class I Climatology Station, West Lombok, NTB Province.From these observations, the average value of rainfall for the last 12 months, from June 2022 to June 2023 is in the range of 65 -364 mm per month.The average rainfall at the study site during the study was 196 mm per month.There is only one suitability class category, which is very suitable based on the results of a comparative analysis using octopus cultivation quality standards.
The results of observations of protection parameters at the study site were divided into three categories, namely protected, adequately protected and unprotected.The results showed that the water depth at the study site was obtained in the range of 20 -25 m.There are two classes that can be seen in this parameter, namely the very appropriate class and the appropriate class.And the results of observing the brightness at the study site were found to be between 20 -25 m.Based on the water clarity quality standard for mussel cultivation, there are only two types of land suitability levels, namely very suitable and suitable categories.The salinity value at the time of observation ranged from 33 -37 ppt and the water conditions were in the very suitable category and the suitability level was appropriate.Dissolved oxygen (DO) values at the time of observation obtained results that were not much different from each sampling point.The results showed that the distribution of DO was even in every water area of West Lombok.The results of observing the distribution of water pH in the field, obtained a pH range of 5,7 -8,4.Observational substrates in Lombok sea waters were found in the form of rocky coral, broken coral and sandy coral.Then, chlorophyll-a data was obtained from Aqua Medium Resolution Imaging Spectroradiometer data with a chlorophyll a value range of 0,26 -1,38 mg/m 3 [14].
In general, Cephalopods are known as animals that grow very fast, reproduce once, then die (semelparous).Male octopuses die after mating, and female octopuses die shortly after hatching and can lose as much as 30 -60% of their initial body weight during egg laying [15].Cephalopods are gonochoritic, sexes are separate, neither are hermaphrodites or sex reversal.They have sexual dimorphism, the male octopus has a hectocotyl arm that will transfer the spermatophore containing spermatozoa to the body of the female octopus.The body size of the male octopus in some species is larger than the female octopus, but in several other species it is found that the female octopus is larger than the male octopus.The weight of the male octopus reproductive organs that mature gonads can reach about 5% of body weight.Female octopuses that have not matured gonads have a reproductive organ weight of less than 1% body weight, but will increase significantly, 30 -50%, in a short time when spawning.Cephalopod gonadal maturity is influenced by the optic gland system and environmental factors, including light, temperature, and food availability [16].
Based on the results of the research, land suitability locations that are very suitable for octopus cultivation are in the Poto Tano and Ketapang Beach areas.Based on the analysis of the scores of several parameters carried out by these two areas, it is suitable for octopus cultivation starting from physical, chemical and biological parameters.The distribution of the Octopus cyanea species is in the tropical waters of the Indo-West Pacific, from the east coast of Africa to the Hawaiian Islands, and from southern Japan to northern Australia [17].Octopus cyanea has a habitat in marine waters in the intertidal area to a depth of 22 meters.This species can be found in holes and crevices in coral reefs, seagrass beds, and along rocky, sandy, and muddy bottom waters [18].This species is active during the day with the highest activity occurring at dawn and dusk.According to [19], this species is found in Indonesia and has a larger population than other species.
The Lembar area is said to be quite suitable for octopus cultivation areas, because the substrate in that area is still quite good and has a protected area, but the score for the water quality parameter is still lower compared to the Poto Tano and Ketapang Beach areas.Because, for water quality is very important in supporting growth, as in the statement of [6] which states that for cephalopods, dissolved oxygen (DO) and other water quality are very important because they are metabolic modulators because they are related to the ability of organisms to process digested food and turn it into biomass.Based on the results of the analysis, Beraringan Beach and Sari Gong Beach are not suitable for octopus cultivation because the scores for all parameters are relatively low, and the most obvious is the parameter of protection.Both of these areas have a score for low protection value, while in cultivation one of the most important things is that the location must be protected from hazards that threaten the biota to be cultivated.
Even though octopus stocks in nature are currently still relatively abundant, if this is done continuously there is a fear that it will experience over-exploitation.It has become common news that the main factor for the decline in octopus stocks in Indonesia is thought to be due to over-exploitation and habitat destruction by humans (anthropogenic pressure).The denser the population and the more developed an area, the higher the pressure on aquatic biota, especially octopus species.This has caused several areas in Indonesia whose waters are damaged and polluted due to this pressure, the biota population is decreasing and they are rarely found.On the other hand, the condition of the waters and biota will be good, of course, anthropogenic pressure must be reduced.Thus, the solution that can be taken to suppress this concern is to domesticate and cultivate octopuses independently so that the preservation and stock of octopuses in nature is maintained.

Conclusion
The conclusion obtained based on the results of the research that has been done is that the characteristic locations of the waters that are very suitable for octopus cultivation are in Poto Tano and Ketapang Beach and the most influential parameters are the substrate, the number of octopuses and rainfall.

Table 3 .
Land Suitability Assessment Evaluation for Octopus Cultivation Locations Evaluation Very Suitable Appropriate Unsuitable