Jurnal IPTEKS Pemanfaatan Sumberdaya Perikanan

Scenario of Scleractinian Larva Dispersal in Sulawesi Waters From A Hydrodynamic Modeling Perspective

Widyastuti Umar — 2023-10-31

Scleractinian coral such as Lobophyllia corymbosa that reproduce by external fertilization have an extended planktonic phase in their life cycle during which they "drift" in the water column. This life cycle phase is an advantage in itself because it increases the capacity of propagules to disperse far from their place of origin. In this hydrodynamic model study, secondary data on bathymetry and tides for the western monsoon period (represented by November 2017) were input into the Surface Water Modelling System SMS 8.1 to simulate the surface current circulation model. In running this program there are 2 important stages, namely GFGEN (Geometry File Generation) and RMA2 (Resources Management Associates-2). The simulation of surface current direction during the west monsoon, which is the reproductive period of L. corymbosa in Indonesia, shows the complexity and distraction of current vectors that occur in the coastal waters around Sulawesi Island. The model results indicate the possibility of spatial and temporal biological networks forming in waters around Sulawesi. The current patterns forming in Sulawesi waters during the west monsoon tend to circulate from north to south due to the higher volume of water mass originating from the Pacific Ocean flowing to the southern part of Sulawesi which is also the entry point for the Indonesian Throughflow (ITF). The larval dispersion model scenario produced for each location (Manado, Toli-Toli, Palu, Mamuju, Spermonde, Sinjai, Wakatobi, and Luwuk Banggai) tended to follow the water movement patterns, with most propagules leaving the location where they were spawned.

Analysis of The Use of Rice Washing Water and Fermented Cassava Peel Waste on Population Growth of Daphnia Magna

Imroatun Nadila — 2023-10-13

Daphnia magna is a potential natural food source due to its nutritional content. The availability of Daphnia magna is not always consistent, posing a challenge to fish cultivation. An alternative solution is to use rice wash water and fermented cassava peel waste as a source of nutrition for Daphnia magna. Rice wash water contains soluble nutrients, while fermented cassava peel waste is rich in nutrients from the fermentation process. This research was conducted in the Fisheries Cultivation Laboratory, 1st Floor, Universitas Muhammadiyah Gresik, in April-May 2023. The research method employed was experimental with five treatments and three replications. P1= 0% rice wash water, 100% fermented cassava peel; P2= 25% rice wash water, 75% fermented cassava peel; P3= 50% rice wash water, 50% fermented cassava peel; P4= 75% rice wash water, 25% fermented cassava peel; P5= 100% rice wash water, 0% fermented cassava peel. Data analysis used analysis of variance and least significant difference test. The results showed that treatment P3 had the highest population density with an average of 2578 individuals. Additionally, treatment P3 also yielded the highest growth rate of Daphnia magna, reaching a value of 28.35. The population distribution across all treatments predominantly showed the total length class <100µm. Overall, the water quality within the temperature range of 26-28°C and pH range of 6.5-8 indicated optimal conditions for the growth of Daphnia magna.

Monitoring Coastal Line Changes Using the Digital Shoreline Analysis System (DSAS) Method in the Coastal Area of Mekkatta Village, Mejene Regency

Haryanto Asri — 2023-12-13

Analysis of coastline changes in Mekkata Village from 2013 to 2023 was conducted using the baseline of the nearest coastline to the mainland. This baseline was used as a reference point for transects measuring changes. The shoreline encompasses the coastline during the research period. Net Shoreline Movement (NSM) was employed to differentiate between erosion and accretion in the study area, showing an average shoreline change value of -9.72 meters towards the mainland, indicating predominant erosion. According to DSAS, it is observed that the coastline of Mekkata Village experienced erosion along 41 transects, while 31 transects exhibited accretion, highlighting significant changes. The most notable erosion area was identified along transects 60, 61, and 62, indicating consistent land reduction. Meanwhile, the most accretion-prone transects were 11, 12, and 13, signifying substantial land addition. The predominant erosion process is suspected to be influenced by the gentle slope of the coastal area and the composition of sand material. Human activities such as deforestation and river mouths also contribute to erosion. The absence of coastal protection structures allows direct waves and currents to impact the shore, potentially causing erosion. Meanwhile, accretion areas around river mouths indicate the formation of emergent land or deltas.

The Application of Remote Sensing and Geographic Information System for Monitoring Changes in Mangrove Forest Area in Torosiaje Village

Agustina — 2023-10-27

This study aimed to analyze the changes in the area of mangrove forests over the last 5 years (starting from 2019-2023) and formulate management strategy directions for those damaged in Torosiaje Village, Popayato District, Pohuwato Regency. The method used was image interpretation and interviews. Landsat 8 image interpretation method for changes in mangrove cover area over the last 5 years. Methods of interviewing and filling out questionnaires to related agencies and the local community in Torosiaje Village. Data analysis used SWOT analysis to determine the strategic direction for mangrove management. The result of the image interpretation showed that the area of mangrove forest in Torosiaje Village in 2020 saw a reduction in the area of 1.04 Ha from 2019. In 2021, there was an increase in the area of 1.68 Ha since 2020, and in 2022, there was another increase of 1.68 Ha. 3.13 Ha since 2021, and in 2023, there was another increase of 6.86 Ha since 2022. Meanwhile, the results of the priority analysis of mangrove ecosystem management strategies in Torosiaje Village are based on the results of the analysis carried out; 3 things become tactical decisions for recommendations in management efforts regarding the mangrove ecosystem, such as increasing public knowledge and awareness about the function of the mangrove ecosystem as well as the skill of the community around the mangrove area, strengthening the institutional management of the mangrove ecosystem area and Torosiaje tourism, creating a waste and waste processing system