Research Article |
Corresponding author: Agus Sabdono ( agus_sabdono@yahoo.com ) Academic editor: Pavel Stoev
© 2024 Agus Sabdono, Diah Permata Wijayanti, Muhammad Hilmi, Eridhani Dharma Satya.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Sabdono A, Wijayanti DP, Helmi M, Satya ED (2024) Possible effects of shipping routes on coral reef degradation and diversity in Karimunjawa Marine National Park, Java Sea. BioRisk 22: 53-64. https://doi.org/10.3897/biorisk.22.124897
|
The Karimunjawa Marine National Park, situated in the Java Sea, Indonesia, is renowned for its rich biodiversity and lively coral reefs. However, amidst the backdrop of this natural beauty, concerns have been raised regarding the potential impacts of shipping activities on the health and diversity of these fragile ecosystems. The increase in maritime traffic, including commercial vessels, tourist boats, and fishing vessels, traversing through the Karimunjawa Marine National Park, raises significant environmental concerns. The movement of these vessels, especially along specific shipping routes, has the potential to disturb and damage coral reefs through various mechanisms. Hence, this study aimed to investigate the possible impacts of shipping routes on the coral abundance and diversity and the coral health in the Karimunjawa Islands, Java Sea, Indonesia.
This study categorized ship routes into West Route, East Route, and Non-Route and assessed coral health and diversity across 15 islands. Key metrics analyzed included coral disease prevalence, coral cover, diversity index, species richness, relative abundance, and evenness, using 15 × 2 m belt transects at 3 and 8 m depths with three repetitions each.
Statistical analysis revealed significant differences in coral abundance and species richness among ship-route groups, but no significant depth-related differences. These results suggest that while shipping routes affect certain aspects of coral health and diversity, other factors may be more influential in shaping coral disease prevalence and overall diversity in Karimunjawa reefs.
Biodiversity, coral reefs, degradation, Karimunjawa, shipping route
More than fifty thousand ships move around the world every year, lugging millions of containers (
In the context of environmental concerns, cruise ships are frequently observed discharging substantial amounts of sewage, food waste, and oily bilge water, containing insoluble particles, into the ocean.
Coral reefs are one of the seabed ecosystems that are very beneficial for human life because of their enchanting aesthetic beauty as a recreation area, their ecological function as a coastal barrier from waves and erosion, and because they are a fish habitat for spawning, rearing, and fishing grounds for various types of fish and other marine organisms, as well as providing active compounds for various pharmaceutical and medicinal purposes (
Shipping routes are the navigating lanes, both natural and man-made, in wide waterways used by large vessels to connect major ports and carry cargo (
The increasing volume of ship traffic, water pollution from ships, and increased direct physical pressure on coral reefs due to ship groundings and anchoring activities are factors that allow damage to coral reefs (
The study area encompasses Karimunjawa Marine National Park, located in the Java Sea, Indonesia. The park comprises a group of 27 islands and surrounding marine areas, renowned for its diverse marine ecosystems including coral reefs, seagrass beds, and mangroves. Based on the tourism destinations and geographic locations, the ship routes were grouped into 3 categories (west, east, and non-routes). The West Route refers to regular arrival in those islands that are situated in the western part of Karimun island including Menjangan Kecil, Burung, Geleang, Cemara Besar, and Cemara Kecil islands. The East Route refers to regular arrival in those islands that are situated in the western part of Karimun island including Menjangan Besar, Gosong Saloka, Kecil, Tengah, and Sintok islands. Non-route refers to irregular arrivals of tourism in those islands including Sambangan, Seruni, Genting, Cendekia, and Menyawakan islands (Fig.
Three belt transects, with 2 × 15 meters (30 m2) in size, were randomly established on each of the 15 islands. These transects were located at depths of 3 meters and 8 meters. The LIT in situ was established in the middle of the belt transect. Hence the total number of LIT and belt transects established is 90 transects. Divers identified all benthic categories and estimated the percent hard coral cover (scleractinian corals) by dividing the total length of occurrence of hard corals by the total length of the transect. Within each belt transect, all scleractinian coral colonies exceeding 5 centimeters in diameter were recorded based on their genus. Corals were further classified as either healthy or diseased (Figs
Diseased colonies exhibited manifestations such as changes in color or structure, tissue loss, necrosis, and abnormal growth. Conversely, healthy colonies displayed no signs of lesions or other indications of compromised health. The prevalence of coral diseases was determined for each belt transect by dividing the number of colonies showing signs of each disease by the total number of colonies present in each transect. The other variables measured for reef degradation were % coral cover, H-index (H’), species richness (SR), and evenness (E).
Parameters observed included coral damage, underwater photography, oceanographic parameters, type and number of corals per transect, number (healthy/sick coral), and percent coral cover. To determine the prevalence and coral cover, the formula used was adopted from
(1)
(2)
The Shannon-Weaver index was used to measure the H’, GR, and E of coral reefs: H’= ∑Si=1 Pi lnPi (3); E = H’/lnS (4)
where: pi = relative abundance, S = species richness; H’= diversity index, and E-evenness.
Analyses of Variance-one way were used to explore the impact of shipping routes on disease prevalence, coral cover, and biological diversity of corals among islands by using SPSS-22 software.
The mean prevalences of coral disease in the west, east, and non-route are 7.5, 5.8, and 5.2 percent, respectively (Fig.
Coral diseases prevalence of Karimunjawa on three shipping routes (Note: the same word characters means no significant differences)
Statistical analysis showed that the impact of shipping-line activity on coral abundance and species richness is significantly different (Table
The effect of shipping route on the Diversity, Abundance, Species Richness, and Evenness of corals.
Shipping route | Diversity (H’) | Relative Abundance (RA) | Species Richness (SR) | Evenness (E) |
---|---|---|---|---|
West route | 2.18 ± 0.7a | 36.6% a | 17.86 ± 0.65a | 0.76 ± 0.02a |
East route | 2.02 ± 0.9a | 26.5% b | 14.04 ± 1.01b | 0.78 ± 0.02a |
Non-route | 2.2- ± 0.8a | 37.0% a | 17.12 ± 0.61a | 0.79 ± 0.01a |
The effect of shipping-route activity in response to increases in depth, specifically, whether relationships exist between depth and prevalence of coral diseases, coral cover, and diversity was presented in Table
The effects of shipping-route activity on the prevalence of coral diseases, % coral cover, and abundance and diversity on different depths.
No. | Depth | Prevalence (%) | Coral Cover (%) | H-Index | Species Richness | Evenness |
---|---|---|---|---|---|---|
1. | 3 m | 6.18 ± .94 a | 67.07 ± 2.42 a | 2.15 ± .06 a | 16.22 ± .59 a | .79 ± .01 a |
2. | 8 m | 6.43 ± .73 a | 62.85 ± 2.89 a | 2.13 ± .04 a | 17.07 ± .72 a | .76 ± .01 a |
The prevalence rate of the disease is the proportion of the coral population with that disease at a point in time. It indicates how many of the corals are sick. Fig.
The discharge of pollution from cruise ships, including decaying waste and ocean dumping, leads to increased acidification of the waters and a significant reduction in oxygen levels. This, in turn, promotes the growth of harmful algae blooms, which pose a serious threat to coral reefs (
Table
In conclusion, the management of the KMNP area is relatively sufficient according to the currently available data, and even though the shipping lanes are quite congested, coral cover is still maintained. The most important result was that between the non-route route and the west route, there were no significant differences in coral abundance and species richness. However, it is necessary to consider again the limited data obtained and the limited research time available, so that it cannot capture long-term trends or changes in coral cover. So, it is necessary to carry out further research to find out the specific causes of differences in coral abundance and species richness in the context of shipping route activities.
The authors have declared that no competing interests exist.
No ethical statement was reported.
The authors express their gratitude for the support provided by the Research and Public Service Institution at Diponegoro University through the RPI scheme. Contract No. 609-63/UN7.D2/PP/VIII/2023.
A. Sabdono, conceived and designed the study methodology, analyzed and interpreted the data, drafted the manuscript, visualization, supervision, project administration, and funding acquisition. D.P. Wijayanti, conceived and designed the study methodology, analyzed and interpreted the data, and wrote—reviewed, and edited the manuscript. M. Helmi, analyzed and interpreted the data, writing—reviewing, and editing. E.D. Satya analyzed and interpreted the data, and data curation.
Agus Sabdono https://orcid.org/0000-0003-0185-8378
Diah Permata Wijayanti https://orcid.org/0000-0003-0326-141X
Muhammad Hilmi https://orcid.org/0000-0002-5270-8612
Eridhani Dharma Satya https://orcid.org/0009-0000-3369-9805
All of the data that support the findings of this study are available in the main text. The data underpinning the analysis reported in this paper are deposited at “Data repository” at https://doi.org/10.3897/biorisk.xx.xxxxxx.
Coral abundance data
Data type: xlsx
Explanation note: Coral abundance of the West Route, East Route, and Non-Route including a total of 15 islands were recorded as raw data to calculate H indexes, evenness and relative abundance.
Coral reef degradation and diversity in Karimunjawa
Data type: docx
Explanation note: This data is summary of data analyzed result from coral abundance and coral cover raw data.