DYNAMICS OF CORAL FISH BIOMASS AND COMMUNITY PERCEPTION IN UTILIZING CORAL REEF ECOSYSTEM,
CENTRAL BUTON DISTRICT, SULAWESI TENGGARA, INDONESIA
(CASE STUDY IN THE SPELMAN COAST COAST WATERS
ABSTRACT
preliminary
As the development of the human population in the world, it is very closely related to the availability of resources, one of which is reef fisheries resources. The challenges of fisheries management in the future are increasingly severe, particularly in poor and developing countries (Costello et al. 2012; Levin and Lubchenco 2008). Often the objectives of fisheries management are not achieved, and outcomes are unclear due to lack of available data and information (Worm et al. 2009).
Spelman Strait coastal waters are one of the straits in Indonesia, precisely located in Central Buton Regency, Southeast Sulawesi Province. One potential is the coral reef ecosystem. Local fishers utilize potential coral reef ecosystem resources by using boats with a capacity of under 1 GT with hand line fishing equipment. According to WWF Indonesia (2011), hand line is a type of tool that uses fishing line using lead or iron ballast. Catching activities carried out alone, and the fishing ground has taken within 15 to 20 minutes from the landing base. According to Karubaba et al. (2001), the distance travelled in fishing is usually not far from the residence and around the coast, ranging from 350-400 m.
In addition to stretching fishing, there is a small portion of local fishermen who still use fishing gear that tends to damage the ecosystem (destructive fishing). As a result, damage to the coral reef ecosystem in the coastal waters of the Spelman Strait (Muis et al. 2020). Muis et al. (2019) also reported that the condition of coral cover in the coastal waters of the Spelman Strait was in a situation of moderate damage (37.71%). Damage to the coral reef ecosystem in the coastal waters of the Spelman Strait that in the future it will be threatened with degradation. Therefore we need a solution for improvement.
The coastal waters of Spelman Strait have exploited after the independent Republic of Indonesia in 1946-1947, and until now (human knowledge). In 1997 until now, the fisheries resources had decreased the catch, so the fishing ground is getting further from the landing base, and the biomass of the score is getting smaller (human knowledge). Utilization of the coral reef ecosystem is closely related to the perception of fishers. Research on coral fish biomass and fishermen’s opinions of the reef ecosystems in the coastal waters of the Spelman Strait is the first to be conducted. It is a hope for the need for baseline data in the management of coral reef fisheries. The purpose of this study was to analyze how coral fish biomass in two fishing seasons, namely the west and east seasons and fishermen’s perceptions of the use of coral reef ecosystems.
Research on coral fish biomass in other waters in Indonesia has been widely carried out, including Central Tapanuli (Suharti and Edrus, 2018), West Lombok (Edrus and Suharti, 2016), Weh Island, Aceh (Hastuty et al. 2014), Oransbari Village, South Manokwari Regency (Parenden et al. 2018), Manggis, Karangasem Regency (Putra et al. 2019), South Misool, Raja Ampat (Prasetya et al. 2014), North Minahasa (Setiawan et al. 2016), Manado Tua Island (Manado Setiawan et al. 2013), Karimunjawa National Park (Yuliana et al. 2017), Lesser Sunda Banda (Setiawan et al. 2017), Batee Island, Aceh Besar District (Nasir et al. 2017), Gita Nada, West Lombok (Yulianto et al. 2018), Pulau Semak Daun (Sriati, 2015)
Material and Method
Study Location
Research sites in the coastal waters of the Spelman Strait at five coral reef station stations consisting of station 1 type fringing reef depths of 3-15 meters, stations 2-5 types of reef burns (patch reef) where station two depths 3-8 meters, stations 3 and 4 depth 5-10 meters and station five depth 3-6 meters. Observations were made in two fishing seasons namely the west season and the east season. The west season is identical with strong winds (big waves) and east season; the waters are relatively shady. The west season usually occurs in January to mid-April, while the eastern season in early May to November (Figure 1). This research conducted for one year, from November 2019 to October 2020.
Material
Retrieval of data in this study uses primary data, namely, direct measurements in the field. The method used is the Underwater Visual Census (UVC). Transect size 75 x 5 x 5 m (length, width and height). Observation and measurement of fish species using an underwater slate system, each diver observes on the left (2.5 m) and other divers on the right (2.5 m). Fish measurements use an estimation system, not exceeding 20% of the actual fish size (Luthfi et al. 2017).
Figure 2. Methods of observation and measurement of reef fish species by UVC (Crosby and Reese 1996; Hill and Wilkinson 2004; Giyanto et al. 2014; Giyanto et al. 2017; Lutfi et al. 2017; Muis et al. 2020).
Data analysis
Fish biomass through length (L) and weight (W): W = a x Lb, where values a and b are constants obtained from Fishbase (Froese and Pauly 2014). Fish in biomass (B) is the weight of individual target fish (W) expand the observation area, can be calculated using the formula:
In assessing reef fish biomass in the coastal waters of the Spelman Strait, the select or low category uses the approach used by McClanahan (2017) (Table 1).
Table 1 Definitions, criteria and category clusters identified in the coral reef community in the coastal waters of the Spelman Strait
Results and Discussion
Composition and Biomass of Coral Fish
The composition of coral fish is closely related to the existence of coral reef ecosystems—healthy coral reef ecosystems, affecting the diversity and abundance of reef fish. UVC results, the composition of reef fish in the coastal waters of the Spelman Strait, still found a variety of families and species that inhabit coral reef ecosystems both in the west and east seasons (Tables 1 and 2).
Table 2 Family, genus and number of reef fish species in the coastal waters of the Spelman Strait in the east monsoon.
Table 3 Family, genus and number of species of reef fish in the coastal waters of the Spelman Strait in the west season.
The diversity of families and species of reef fish found at all observation stations indicates that coral reef ecosystems still have a positive impact on the availability of food and water parameters suitable for the sustainability of reef fish resources. Muis et al. (2019), the water parameters in the coastal waters of the Spelman Strait are very suitable for the life of coral reef ecosystems.
Fish biomass is a driving force for fishers in exploiting or catching reef fish, especially reef fish that have significant economic value and are export commodities that are targeted by fishermen. Based on observations at all stations, reef fish biomass still contributes to fishers in its use, although some families have low biomass, overall fish biomass is very high (Tables 3 and 4).
Table 4 Coral fish biomass (target) in the west season in the coastal waters of the Spelman Strait
Table 5 Coral fish biomass (target) in the coastal waters of the Spelman Strait in the east monsoon
West season coral fish biomass in the Scaridae family is in the high criteria, the Acanthuridae and Lutjanidae families are in the reasonable standards, and the Lethrinidae, Haemulidae, Siganidae and Serranidae families are in the low rules (Table 4). The east season fish biomass in the Scaridae, Acanthuridae and Lutjanidae families is in the high criteria, the Siganidae and Serranidae family are in the common standards, and the Lethrinidae family and Haemulidae are in the low rules (Table 5).
Reef fish biomass in the two seasons is relatively different, such as the Acanthuridae and Lethrinidae families wherein the west season is low. The east season is high, so are the Siganidae and Serranidae families, in the west season the biomass is small, and in the eastern season, the biomass is medium. The Lutjanidae family is in the west season moderate and east season-high biomass. The difference in biomass is related to the fishing patterns adopted by the coastal fishermen of the Spelman Strait waters, wherein the western season catching economically important fish (export quality) namely red snapper (Lutjanidae family) and grouper fish (family Serranidae), this is based on wisdom local. Fishing hooks in the west season use large fishing hooks (5, 6, 7 and 8) and in the eastern season are small (15, 16 and 17).
Different from the west and east season biomass at stations 2, 3, 4 and 5, the Lethrinidae family and Haemulidae family at stations 3 and 5 were not found. This is caused by arrests using bombs (Muis et al. (2020). Damage to coral reefs in the Spelman Strait coastal waters based on observations caused by the use of bombs. Muis et al. (2019) reported the condition of live coral cover in the coastal waters of the Spelman Strait in moderate condition (37.71) and dead coral (33.71). According to McClanahan et al. (2011) and Karr et al. (2015) reported damage to coral reefs in the western Indian Ocean (WIO), the Caribbean, in general, was caused by excessive pressure, so that coral fish biomass also decreased. Coral cover significantly affects the biodiversity of reef fish resources, the better the coral reefs, the better biodiversity, because of the availability of food, the availability of protection and the availability of nursery ground.
The reef fish resources of the Spelman Strait coastal waters, several economically essential fish families began to be threatened by their existence such as the Lethrinidae and Haemulidae families. This is influenced by anthropogenic influences that use fishing gear that is not environmentally friendly. The effect of destructive fishing is not only damaged resources but coral reefs which pose a threat. According to Puspito (2010), coral reef ecosystems in Indonesia are predicted to be at a 75% damage level due to bombs. Pet-Soeda et al. (1999) the effect of a bomb explosion using a beer bottle is estimated to damage the coral reef ecosystem by 5 m2. In all observation stations, coral fragments were found (Figure 3). According to Sitorus and Tarigan (2009), damage to coral reefs due to bombing is marked by the number of coral fragments.
This is different from the stretching fishing line, which is an environmentally friendly and highly selective fishing line because it is compatible with fish mouth openings (Figure 4). According to Irnawati et al. (2012), as a form of management effort which is responsible for maintaining coral fishery resources in the Karimunjawa National Park area is the use of fishing gear, so that the presence of groupers is not overfished.
Figure 3. As a result of arrest using explosives
Figure 4. Fishing gear for catching reef fish
Anthropogenic influences also determine the sustainability of coral reef ecosystems in the coastal waters of the Spelman Strait. Research by Parenden et al. (2018), in the coastal waters of Kampong Oransbari, South Manokwari Regency, differences in utilization rates and the percentage of coral cover are different causes, the abundance value and reef fish biomass. By the statement of Acosta and Robertson (2002), the abundance and diversity of reef fish is an indicator of the size of the coral cover.
Reef fish is a neatly arranged community and has a level of the food chain based on past, environmental, ecological and anthropogenic influences (Pellessier et al. 2014; MacNeil et al. 2015, McClanahan et al. 2015, Mellin et al. 2016b). According to Bellwood (1988), reef fish are classified based on ecological associations between reef fish and coral reefs. The role of coral reefs in reef fish provides food, protection and as a place to spawn (Nybakken 1992). The higher species composition, biomass, and diversity of reef fish can increase the resilience of coral reefs that are threatened by excessive pressure in their use (McClanahan et al. 2011; Graham et al. 2015). Therefore, to maintain fish biomass, management needs to be wise and prudent in preserving the sustainability of ecosystems. Based on research by McClanahan and Jadot (2017) in the waters of Madagascar, the effects of overfishing and environmental influences cause disturbed fish biomass.
Community Participation in Management of Coral Fisheries through
Focus Group Discussion (FGD)
Community participation in the management of fisheries resources is significant to note because the community is the user of these resources. Fisheries resources are resources that can be managed by everyone (open access). Because of its free access status, a prudent approach is needed in its management. FGD with stakeholders on the management of coral fisheries in the Spelman Strait coastal waters obtained several problems and the resulting solutions. In the assessment of fisheries resource utilization (Table 6), the community has very high expectations for the sustainability of coral fishery resources.
Table 6 Frequency Focus Group Discussion (FGD) management of coral fisheries in the coastal waters of the Spelman Strait.
Source: Primary data processed
In general, the damage to coral reef ecosystems in the coastal waters of the Spelman Strait is caused by fishermen’s perceptions of coral reef ecosystems. This perception is related to the use of explosives in catching reef fish. Other opinions are closely associated with the level of fishermen’s knowledge of coral reef ecosystems such as coral reefs are not living things. This phenomenon has been ongoing since the beginning of utilization until now and is very important to be evaluated. The coastal waters of the Spelman Strait have never been evaluated, so they need a strategy in their management. Therefore, it requires strong institutions to save coral reef ecosystems, such as stakeholder collaboration, consisting of local governments, religious leaders, traditional leaders, universities, non-governmental organizations (NGOs), youth leaders, fishers community leaders.
Strong institutions will dampen fishers who use tools that are not environmentally friendly, protect sand mining and garbage disposal, thereby avoiding conflicts in resource use. According to Freitag et al. (2019), unity is needed in management, so it is expected that environmental disturbance to the ecosystem can be responded to appropriately.
Coral reef ecosystems in the coastal waters of the Spelman Strait need to be saved for the economic sustainability of fishers, regional food security and future generations. Anglers who use the Strait are small scale fishermen. In the next scenario is needed to save coral reef ecosystems from degradation. As reported by McClanahan (2017), to recover reef fish biomass, a stakeholder collaboration scenario model is necessary.
Management of reef ecosystems is also very dependent on the availability of data and information, making it difficult to save or improve management systems (McClanahan 2017). Examples of coral reef ecosystems in the Caribbean, due to lack of data and information and weak law enforcement, make it difficult to manage (Salas et al. 2017).
The involvement of religious leaders/clerics/clerics also in resource management is significant. According to religious leaders, the pattern of fisheries resource management that is not environmentally friendly and tends to be destructive is a grave sin because it will leave bad things for the next generation. For example, the local wisdom of the mosque-based Sasi Laut on Ambalau Island, South Buru Regency, the involvement of the Imam of the Mosque and the King greatly influences the sustainability of fisheries resources (Adrianto et al. 2011), as well as Sasi Church in the Haruku and Kei islands (Adrianto et al. 2011 ). In management, a conceptual model and policy are needed to identify vulnerabilities in the present and future (Berrouet et al. 2018), so that the utilization of coral reef ecosystems can be sustained and fishermen welfare increases (Yusuf et al. 2018).