Observation of Coral Reef and Macroalgae Competition in the Sempu Strait, Malang

Isdianto, Andik; Kurniawan, Andi; Wicaksono, Agus Dwi; Marhaendra, Quanta Nur Ihza; Putri, Berlania Mahardika; Fathah, Aulia Lanudia; Asadi, Muhammad Arif; Luthfi, Oktiyas Muzaky; Pratiwi, Dwi Candra; Harahab, Nuddin

doi:10.12911/22998993/170246

Cited by 4 publications

(4 citation statements)

References 21 publications

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“…Herbivorous fish are able to clean algae from dead coral so that they can help the planula attachment process in the coral recruitment process (Chung et al 2019). Basically, macroalgae grow more rapidly than corals, resulting in competition for growing space (Isdianto et al 2023). Other research shows that the number of individuals, types, and sizes of herbivorous fish play a crucial role in coral reef resilience, which functions as a controller of algae growth, such as Scaridae (Plass-Johnson et al 2015;Wulandari et al 2022).…”

Section: Reef Fish Abundancementioning

confidence: 99%

Reef fish monitoring as a coral reef resilience indicator in the Sempu Strait, South of East Java, Indonesia

BINTORO,

ISDIANTO,

HARAHAB

et al. 2023

Biodiversitas

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Abstract. Bintoro G, Isdianto A, Harahab N, Kurniawan A, Wicaksono AD, Maharditha R, Fathah AL, Putri BM, Haykal MF, Asadi MA, Setyanto A, Lelono TD, Luthfi OM, Pratiwi DC. 2023. Reef fish monitoring as a coral reef resilience indicator in the Sempu Strait, South of East Java, Indonesia. Biodiversitas 24: 4950-4959. Sempu Island is designated as a nature reserve which is surrounded by a fairly high diversity of coral reefs. Since the high activities of fishing ports near this island, the anthropogenic pressure seriously became a threat to the biodiversity of coral reefs in this nature reserve. Continuous observation of reef fish is an important activity to monitor the coral reef health condition. Since then, bimonthly monitoring using an underwater visual census has been conducted from October 2021 to May 2022. Based on these observations obtained that the average reef fish abundance was in the "low" category, namely 0.516 ind/m2 in October 2021, 0.527 ind/m2 in December 2021, 0.522 ind/m2 in February 2022, and 0.378 ind/m2 in May 2022. The abundance of reef fish obtained consisted of three categories: indicators, targets, and majors. Overall, the Pomacantridae family, from the major fish category, has the largest abundance compared to other families. While the range of coral coverage was 6-21.3%, which was included in the "bad" category. There was a relationship with a value of 0.462 (medium) between coral cover and fish abundance. The abundance of reef fish at 21.4% was influenced by coral cover, while the remaining 78.6% was influenced by other factors outside of the tested variables. The decline in reef fish abundance in 2015-2022 can be caused by a decrease in coral cover in the Sempu Strait.

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Section: Reef Fish Abundancementioning

confidence: 99%

Reef fish monitoring as a coral reef resilience indicator in the Sempu Strait, South of East Java, Indonesia

BINTORO,

ISDIANTO,

HARAHAB

et al. 2023

Biodiversitas

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“…For zooxanthellae to perform photosynthesis, water clarity is also essential (Muqsit et al, 2016). According to Isdianto et al (2023), coral reefs continue to flourish in the Sempu Strait due to the environmental characteristics of the study site. Although some parameters provide optimum living conditions for biota, others do not, and conditions for invertebrates and coral reefs are not optimal.…”

Section: Water Qualitymentioning

confidence: 99%

“…The coral reef in the Sempu Island Natural Reserve is a type of edge reef (fringing reef) with more corals than the opposite side (Luthfi et al, 2017b). The coral cover in the waters of the Sempu Strait decreased from 23.3% in 2016 (Luthfi et al, 2017a) to 11.5% in 2021 (Isdianto et al, 2023). In addition, the vast majority of the 600,000 to 9 million species of biota that inhabit coral reefs are macroinvertebrates (Fabricius et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Assessment of Community Structure of Macroinvertebrates, Coral Cover and Water Quality in Sempu Strait, Malang Regency, East Java

Isdianto,

Kurniawan,

Wicaksono

et al. 2023

J. Ecol. Eng.

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Due to the sensitivity of invertebrates to environmental changes, their presence can serve as an indicator of coral reef health and water quality. This study seeks to ascertain the abundance of invertebrates, the structure of the invertebrate community, and their relationship with coral cover and water quality parameters in the waters of Sempu Strait. The belt transect method and the underwater photo transect (UPT) are used to determine the abundance of invertebrates and coral cover, respectively. Temperature, pH, DO, salinity, and water clarity are measured for water quality. According to the study's findings, seven of the nine invertebrate species were found. Between October 2021 and May 2022, seven of nine invertebrate biota categories, 733 species, and 606 species dominated by Diadema sea urchins were observed every two months. The invertebrate abundance ranged from 0.024 to 0.512. A low and imbalanced invertebrate diversity ranges from 0.078 to 0.493 (H' < 1). The range of the equality index (E < 0.4) is between 0.04 and 0.22, indicating a low community index. There are three levels of dominance index values: low, medium, and high. Due to their abundance, Diadema sea urchins dominate the Sempu Strait, particularly near the Jetty Station with its port activity. Coverage of coral reefs varies between 6% and 21.3%, indicating low and damaged corals. The correlation between coral cover and invertebrate abundance is moderate in Banyu Tawar and Rumah Apung (0.480 to 0.490), whereas it is weak in Watu Meja,. The abundance of invertebrates has a weak link with values ranging from -0.037 to -0.283 for water clarity, temperature, salinity, DO, and pH, but it has a strong correlation with a value of 0.610 for current velocity. The environment, including human activities and water quality, has a significant impact on macroinvertebrate communities. Environmentally tolerant macroinvertebrates will outcompete the vulnerable ones.

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“…These browsers play a crucial role in mitigating coral overgrowth and shading caused by macroalgae, and they can significantly contribute to reversing transitions between coral and algal dominance phases (Green and Bellwood 2009). Grazers reduce seaweed, preventing coral overgrowth and shading by macro-algae (Isdianto et al 2023). In Bonaire, Dutch Caribbean, herbivores were found to graze coral reef ecosystem giving positive impact on the abundance of adult and juvenile corals, and a decrease in macroalgae abundance (Steneck et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Dynamic of coral recruits in the Karimunjawa National Park, Central Java, Indonesia

TARIGAN,

MUNASIK,

WIJAYANTI

et al. 2024

Biodiversitas

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Abstract. Tarigan SAR, Munasik, Wijayanti DP, Muhidin, Rohman EA, Pardede S. 2024. Dynamic of coral recruits in the Karimunjawa National Park, Central Java, Indonesia. Biodiversitas 25: 869-880. After a disturbance event, coral reefs can recover naturally by recruiting new corals. These can be affected by environmental factors like the substrate's physical and biological structure, predation, and accidental mortality of recruits by grazers, as well as the number and size of parent corals supplying larvae. This study examined the connection between newly recruited corals and biological factors such as sea urchin density, herbivorous fish abundance, and hard coral coverage. The study was monitored changes in coral cover, juvenile coral density, herbivore abundance, and hard coral coverage at 43 locations and two depths (shallow; 2-3 m) and deep (8-10 m) from 2013 to 2022. The locations were distributed across six different zone systems: the core zone, protection zone, tourism zone, traditional fisheries zone, aquaculture zone, and rehabilitation zone. Multiple Linae Regression, ANOVA test, and Principal Component Analysis were employed to assess the relationship between coral recruitment and other variables. Results indicated that the coral recruitment density was not significantly different when comparing different zoning systems (two-way ANOVA test, P-value>0.05). Based on the PCA analysis, we found that in 2013 and 2019, excavator, sea urchin, browser, and hard coral have a positive relationship with coral recruitment, which implies that coral recruitment would increase as sea urchin, browser, and hard coral increase. Meanwhile, in 2019 and 2022, coral recruitment has a negative relationship with scraper, and also with hard coral growth (although only in 2022), implying that coral recruitment would decrease if scraper and hard coral increase. The study recommends restoring the role of herbivorous species in Karimunjawa National Park (KNP) by prioritizing them in conservation efforts and managing their populations.

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Observation of Coral Reef and Macroalgae Competition in the Sempu Strait, Malang

Cited by 4 publications

References 21 publications

Reef fish monitoring as a coral reef resilience indicator in the Sempu Strait, South of East Java, Indonesia

Reef fish monitoring as a coral reef resilience indicator in the Sempu Strait, South of East Java, Indonesia

Assessment of Community Structure of Macroinvertebrates, Coral Cover and Water Quality in Sempu Strait, Malang Regency, East Java

Dynamic of coral recruits in the Karimunjawa National Park, Central Java, Indonesia

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