Effect of anthropogenic activity on benthic macroinvertebrate functional feeding groups in small streams of West Sumatra, Indonesia

Functional feeding groups (FFG) of benthic macroinvertebrates have been used to characterize the condition of aquatic ecosystems, changes in land use, and assess the river health ecosystems. Ranggeh River belongs to a small river that plays a vital role in breeding the native fish of Lake Maninjau (West Sumatra). Agricultural activities and human settlements around the Ranggeh River can threaten life and change the FFG of benthic macroinvertebrates. This study aims to analyze and observe changes in water quality by anthropogenic activities and their impact on FFG benthic macroinvertebrates in a small stream (Ranggeh River). This research was conducted at the Ranggeh River segment from February to August 2019. A sampling of benthic macroinvertebrates was carried out using a Hess sampler on the riffle. This study shows that predators, shredders, and scrapers are still dominant when the Ranggeh River ecosystem is still minimally disturbed by agricultural activities and settlements. However, when agriculture activities and human settlements become more massive, the dominant FFGs are collector-filterers and collector-gatherers. Sedimentation parameters (turbidity and % embeddedness) in the Ranggeh River greatly influence predators, scrapers, and shredders. FFG has excellent potential to be further developed in preparing biocriteria for the effects of agriculture and human settlements

ANCAMAN JENIS IKAN ASING LOUHAN TERHADAP IKAN ENDEMIK DI DANAU MATANO, SULAWESI SELATAN

Lake Matano is one of the ancient lakes in Sulawesi where some endemic fish species of Telmatherina, Mugilogobius, Oryziasand Glossogobius matanensis lived. The presence of alien species can be on threat for the loss of biodiversity in fresh waters, including endemic fish in Lake Matano. The research aim to review the threat of louhan fish as alien species to endemic fish in Lake Matano. The study was conducted in Lake Matano at five stations in April and August 2015 namely Lawa, Nuha, Petea, Pantai Impian, and Pantai Kupu-kupu. Sam-ples were collected using experimental gillnet with mesh size of ¾; 1; 1¼; 1⅟2; 2; 2,5; and 3 inches. Fouteen species were found consist of 10 endemic species and red list.These were three of genus Glossogobius, seven species of Telmatherina, and four alien species of the carp (Cyprinus carpio), louhan, gourami (Trichopodus trichopterus), and tilapia (Oreochromis niloticus). The most common species of endemic fish is T. antoniae. Louhan is the result of a hybrid species Amphilopus citrinellus x Cichlasoma trimaculatum. The abundance of louhan is 64 in April and 40 fishes in August, respectively at a time caught. The percentage ratio of louhan to endemic fish was of 8.6% and 18.3%. This indicated that the louhan fish tend to be invasive and certainly threatened endemic fish survival in this lake. The maturity of gonads of louhan is in the level of I - IV that enables the fish to reproduce quickly

The Impact of Anthropogenic Activities on Benthic Macroinvertebrates Community in the Ranggeh River

Ranggeh River is one of the inlets of Lake Maninjau (West Sumatra, Indonesia), which has a vital role in supporting the life of native fish. Increasing anthropogenic activities (agriculture and human settlements) around the river can harm benthic macroinvertebrates as natural food for fish. Therefore, this study aimed to analyze and observe water quality changes and their impact on the benthic macroinvertebrate communities in the Ranggeh River. Sampling was conducted from February to August 2019 using the Hess Sampler tool. The results indicate that the anthropogenic impacts around the Ranggeh River on water quality has changed the macroinvertebrate benthic community structures (composition, abundance, and biological index). Furthermore, the Ephemeroptera Plecoptera and Trichoptera (EPT) number of taxa index were superior in reflecting disturbances in the Ranggeh River compared to the Family Biotic Index (FBI) and the Percent Model Affinity (PMA). In conclusion, the anthropogenic effect on the macroinvertebrate community in the Ranggeh River prominently was caused by habitat changes rather than enrichment by nutrients (TN and TP)

Development of the silver eel (

The Lake Poso system is located in Central Sulawesi and is connected to the Tomini Bay by the Poso River. It is known that five out of nine Indonesian eel species were found at the Poso River. Anguilla marmorata is the most caught species. However, uncontrolled catching during downstream migration and the construction of a hydropower plant threaten the silver eel in the Lake Poso system. Research on silver eel (A. marmorata) in Lake Poso was conducted to determine and compare the condition of gonad development as part of the reproductive process. This represents essential information in eel fisheries management in Lake Poso. The eels were collected through bamboo traps (waya masapi). The present study calculates the GSI and HSI values, and histological analyses characterize the gonad. The GSI of eel ranges from 1.95 to 5.69%, and the HSI value ranges from 0.83 to 1.16%. Histological observation showed that eels from Tentena (Lake Poso outlet) and from the estuary of Poso River have ovaries in the early vitellogenic stage (III) and the vitellogenic stage (IV)

Perspective plan for sustainable eel management in Lake Poso, Central Sulawesi

Lake Poso has high eel potential and a strategic position in supporting the development of eel fisheries in Sulawesi. Lake Poso is out of 15 national priority lakes in natural resources and environmental management programs. The catch of eel from Lake Poso is reported to have been decreasing for the last twenty years. Several factors causing the decline in eel populations are fishing activities, disruption in migration routes, and other factors such as changes in habitat and environmental conditions. The sustainability of the life of the Poso eel is determined by the success of the eel migration process. The migration of adult eels to the sea and young eels from glass eels to freshwater habitats must continue. The perspective plans that can be done to manage Poso's eel resources include 1) Socializing the eco-biological characteristics of eels as catadromous fish; 2) Establishing conservation areas and regulation of eel fishing; 3) Increasing eel population through restocking 4) Integrating fisheries and aquaculture activities; 5) Developing eel culture technology through size segmentation production; 6) Developing an eel migration monitoring system; 7) Building a cross-sectoral forum and put a joint action program; 8) Proposing the Poso eel Research and Conservation Center