Jurnal Ilmu Kelautan SPERMONDE

PRELIMINARY STUDY ON THE CONTENTS OF THE DIGESTIVE TRACT OF THE FISH Sicyopus zosterophorus (Bleeker, 1856) FROM THE BOHI RIVER, BANGGAI DISTRICT, CENTRAL SULAWESI

Abdul Gani — 2024-08-05

ABSTRACT

Sicyopus zosterophorus (Gobiidae) has a habitat in clear and fast-flowing rivers. This fish species is found in several rivers in Banggai Regency, Central Sulawesi, one of which is the Bohi River. Studies on the type of food S. zosterophorus in the Bohi River have never been carried out. Therefore, it is necessary to conduct research that aims to determine the type of food S. zosterophorus in nature as important information for life history and feeding in controlled habitats. This research was carried out from December 2019 to January 2020. The fishing was done using a scoop net by snorkeling to get fish at the bottom of the river. The fish obtained were then preserved using 5% formalin and then taken to the laboratory for identification of digestive tract contents. Data on the composition and percentage of types of food in the digestive tract were processed using Microsoft Excel 2010 and analyzed descriptively. The results showed that the contents of the digestive tract of S. zosterophorus were dominated by insects (74%), crustaceans (7%), plants (5%), and phytoplankton (3%). The contents of the digestive tract were not identified as much as 11%. Based on this, S. zosterophorus in the Bohi River is categorized as stenophagic and is a carnivorous fish, especially insectivorous and phytobenthic eaters. This research can be used as a basis for providing natural food for S. zosterophorus in aquaculture.

Keywords: Goby fish, insectivorous, phytobenthic, stenophagic

PREFERENCE OF SPONGE PREDATORY FISHES ON CORAL REEF ECOSYSTEMS WITH DIFFERENT ENVIRONMENTAL CONDITIONS ON HOGA ISLAND, WAKATOBI

Andi M. A. Pratama — 2024-08-05

Degradation of coral reefs due to changes in environmental conditions causes corals to experience a decline in the number of organisms. Sponges, one of the components that make up the coral reef ecosystem, are known for their adaptability. Thus, the role of spongivore as distribution controllers is essential to assess. This research aims to determine the relationship between hard coral cover and sponge cover, the relationship between environmental parameters and sponge cover, and the preferences of predatory sponge fish. This research was conducted in July 2018 on Hoga Island, Wakatobi, by taking two stations with different conditions between clear and turbit water. At each station, benthic cover data was collected using the LIT (Line Intercept Transect) method, and environmental parameter data was collected using CTD (Conductivity Temperature Depth) and sediment traps. Predatory fish abundance data was collected using the belt transect and UVC (underwater visual census) methods, and the preferences of predatory fish were observed with visual observations for 5 minutes. The research results found that hard coral cover and sponge cover had an inverse relationship. Environmental parameters that significantly affected sponge cover were turbidity and sedimentation rate and high preference values for spongivore fishes.

SPATIAL DISTRIBUTION AND STRUCTURE OF PHYTOPLANKTON COMMUNITIES THAT HAVE THE POTENTIAL TO CAUSE HARMFUL ALGAE BLOOMS (HABS) IN THE WATERS OF LAIKANG BAY, SOUTH SULAWESI

Fadilla Trimurti — 2024-08-05

The presence of nutrients such as nitrate and phosphate can have a positive impact on phytoplankton growth. However, if the nutrient concentration is very high in the waters, it can cause an explosion in the phytoplankton population or Harmful Algae Blooms (HABs) in the waters. Phytoplankton explosions in waters have a negative impact on the surrounding ecosystem, marine biota, and humans. This research aimed to analyze the spatial distribution and structure of phytoplankton communities that can potentially cause HABs in the waters of Laikang Bay, South Sulawesi. This research was conducted in June 2021. The research found 20 species of phytoplankton HABs from 2 classes, namely Bacillariophyceae (8 types) and Dinophyceae (12 species). The Bacillariophyceae class has a higher percentage, 93%, and Dinophyceae at 7%. The abundance status of phytoplankton HABs is classified as not blooming, with the highest abundance found at Station 4 (control), namely 210 ± 80 cells/L. The HABs phytoplankton diversity index (H') is moderate with a value of 1.576 – 2.332, the uniformity index (E) of Station 1 (west) and Station 4 (control) is moderate with a value of 0.568 and 0.582 while Station 2 (north) and Station 3 (south) is classified as high, namely 0.807 and 0.823, the dominance index (D) is classified as low with a value of 0.135 – 0.357. Spatially, phytoplankton HABs based on the station can be divided into five groups. The results of the PCA analysis show that substations 1.A, 1.B, 1.C, 2.A, 2.B, and 2. C are characterized by high temperature and salinity parameters. Substations 3.A, 3.B, and 3.C are characterized by high nitrate and phosphate parameters. Meanwhile, substations 4.A, 4.B, and 4.C are characterized by high parameters of brightness, current speed, and pH and are associated with a high abundance of phytoplankton HABs.

CHECKLIST OF SEA CUCUMBERS SPECIES FROM BILUHU TIMUR WATERS, TOMINI BAY, GORONTALO, INDONESIA, BASED ON THEIR OCCURRENCE ON NEW MOON AND FULL MOON OF LUNAR PHASE

Faizal Kasim — 2024-08-05

This study presents a comprehensive checklist of sea cucumber species found in Biluhu Timur waters, Tomini Bay, Gorontalo, Indonesia, across the new moon and full moon lunar phases. The survey identified eight species across five genera, including Actinopyga miliaris, A. mauritiana, Holothuria scabra, and H. leucospilota, noting significant distribution patterns influenced by lunar cycles and different biomes at three stations. Actinopyga miliaris and A. mauritiana, both classified as Vulnerable, were more active in the seagrass biome of Station I during the full moon. H. leucospilota, classified as Least Concern, was highly prevalent in the sandy substrate biome of Station II during the new moon, indicating a strong ecological association with that habitat. Stichopus horrens, classified as Data Deficient, showed notable activity in the coral reef biome of Station III. Environmental parameters such as water temperature, salinity, and pH were measured at each station to understand the conditions influencing these species. This study highlights the importance of lunar phases, biomes, and environmental variables on sea cucumber distribution. The findings underscore the need for conservation efforts that consider these factors to protect species vulnerable to overfishing and habitat degradation. Further research should include genetic analysis and expanded temporal and spatial scales to develop effective conservation strategies and sustainable management practices

ESTIMATING SEASONAL PATTERNS OF FISHING FOR ANCHOVIES (Stolephorus Sp) LANDED AT PPI PAOTERE, MAKASSAR, SOUTH SULAWESI: AN APPROACH TO FISHING BUSINESS EFFICIENCY

Muhammad Ridwan — 2024-08-05

The exploitation level of fish resources should be based on effectiveness, efficiency and business sustainability. One of the efforts to implement these three aspects is to understand the seasonal pattern or the best time to catch the fish target. The aim of this research was to estimate the pattern of the anchovy fishing season based on production data landed at PPI Paotere Makassar, South Sulawesi. Data is collected from the PPI and analyzed using the moving average techniques. Results showed that the seasonal pattern of anchovy fishing is estimated to increase in the transition season to the eastern season (IMP > 100%) and reach a peak in September (IMP = 134.74%). Descriptively, the fishing season, especially the peak season, was thought to occur because these fish are probably associated with optimum conditions for oceanographic parameters such as sea surface temperature, chlorophyll-a concentrations and surface current conditions. Information on anchovy fishing season patterns is really needed by marine fisheries managers, both government and private, in managing efforts to exploit fish resources wisely and sustainably.

EVALUATING THE DIVERSITY AND ABUNDANCE OF MARINE FISH IN THE MAKASSAR STRAIT, INDONESIA THROUGH ENVIRONMENTAL DNA (EDNA) ANALYSIS

Nita Rukminasari — 2024-08-05

The recent adoption of environmental DNA (eDNA) represents an innovative method for assessing the presence of aquatic vertebrate species, providing a relatively straightforward approach with significant implications for conservation biology. In our investigation, we employed eDNA metabarcoding to explore the diversity of fish in the Makassar Strait. We collected eDNA from samples taken both at the surface and from the water column (15 m depth) at two specific locations within this region. The reliability of the MiFish-U primer set methodology in estimating fish diversity in the Makassar Strait was assessed. In a single survey, based on four water samples from the Makassar Strait, we successfully identified 11 marine fish taxa at the species level. These taxa belong to 8 families across 8 orders. The predominance of reef-dwelling species suggests that coral reefs play a dominant role as the primary ecosystem in this area. Among the surveyed sites, Barru Waters exhibited the highest species richness (7 species), while Pangkep Waters only revealed 4 species. Through the application of eDNA metabarcoding, this study provided a means to assess fish diversity, delivering crucial foundational information. Our findings highlight the cost-effectiveness of the eDNA metabarcoding method as a powerful scientific tool for the management and conservation of marine fish resources in the Makassar Strait.

IDENTIFICATION OF GREEN ALGAE (CHLOROPHYTA) GENUS HALIMEDA IN THE WATERS OF MABA DISTRICT, EAST HALMAHERA

Wilya Ananda — 2024-08-05

Halimeda is a genus of calcified alga that inhabits tropical aquatic environments. The presences of Halimeda is essential for waters around mining sites, such as the waters of Maba District, wich is the center of mining in East Halmahera. As a calcareous organism, Halimeda functions as a buffer to neutralize the pH of waters. Although the presence of Halimeda in waters is not rare, studies on Halimeda taxonomy in Indonesia are very limited. Identification of Halimeda species can be done by looking at morphological and anatomical structures as an alternative based on the key to determining Halimeda species in the Indo-Pacific by Hillis & Collinvaux (1980), in addition to looking at DNA sequences. This study was aimed at identifying Halimeda species distributed in the waters of Maba District, East Halmahera based on morphological and anatomical characteristic. Besides, it also aims to determine the distribution and similarity of species between sampling locations. Sampling was carried out using purposive sampling method. Halimeda sample collection was prepared before identification. Eight species of Halimeda were found from four sampling sites, namely Halimeda cylindracea, H. distorta, H. macroloba, H. opuntia, H. simulans, H. discoidea, H. melanesica, and H. tuna. In additional to these eight species, seven unidentified Halimeda species were also found based on morphological and anatomical characteristc. Most similarity percentage of Halimeda species was found between Tanjung Buli-Monoropo at 75% and the lowest between Gee Island-Pakal Island (0%). The distribution of Halimeda species in waters in influenced by many factors, including substrate type, nutrients, light intensity, salinity, pH, temperature, depth, wave and current action.

COMPARATIVE STUDY OF COASTLINE CHANGES USING THE IJIMA SATO SEDIMENT TRANSPORT METHOD IN RELATION TO THE CONSTRUCTION OF GROIN STRUCTURES IN THE RANDUPUTIH BEACH AREA, PROBOLINGGO REGENCY

Yani Nurita Purnawanti — 2024-08-05

As the population increased, the requirement for housing increased as well. The Randuputih coastal area on the coasts of Probolinggo Regency is located in the northern part of Java Island, so most residential areas are in the north coastal area. In this area, there is housing development close to the coastal area. With the housing development near the Probolinggo coastal area, we plan to build a coastal protection building as a groin structure to prevent erosion along the coast. In designing the groin structure, it is necessary to analyze the coastline changes in the Randuputih coastal area, Probolinggo Regency, to calculate the length of the groin built in that area. As a reference for calculating the groin structure, the analysis carried out observed changes in the coastline over 20 years (2003-2023). The sediment transport method used is the Ijima Sato sediment transport method because this method approximates changes in coastlines based on observations over 20 years in the Randuputih coastal area, Probolinggo Regency. The average sediment transport is 3.74 m³/day from the northwest. Adding three groin structures along 700m can maintain coastline change stability by up to 6.61%. Before the groins were applied, the average coastline change was 34%.