Surabaya City has a water reservoir system that has the same function as a reservoir called bozem. There are some bozem in Surabaya, such as Bozem Moro Krembangan, Kalidami, Bratang, Rungkut Industri, Wonorejo, Kedurus, and Jurang Kuping. Bozem was built because Surabaya is a city prone to flooding due to lack of water catchment areas.
As we know, development in the city of Surabaya is growing rapidly. It brings an impact with the reduction in water catchment areas. In general, bozem was built without diverting rivers or other public waters. In general, bozem functions to control and store water; however, it can also be used for fish farming and irrigating rice fields.
One of bozem that is used for fish farming is Bozem Moro Krembangan.聽Fish culture in Bozem Moro Krembangan uses a floating net karamba system, and the type of fish being cultivated is the African catfish (Clarias gariepinus).听罢丑别 bozem as a reservoir of water, both from rivers and from household organic wastewater, ensures fertile waters for the growth of microorganisms such as bacteria and fungi.聽Considering the function and condition of bozem waters, it is necessary to study whether fish cultivation in bozem waters, especially in Moro Krembangan, is feasible, especially regarding the occurrence of infections of聽Aeromonas hydrophila听补苍诲听Saprolegnia sp.聽in the cultivated fish.
The research was conducted to identify聽Aeromonas hydrophila听补苍诲听Saprolegnia sp., which is a type of bacteria and fungi that cause fish disease to African catfish cultivated in Bozem Moro Krembangan.聽Fish disease due to bacterial pathogen attack (bacterial disease) is one of the severe problems for catfish farmers because it has the potential to incur loss to fish farmers.
Bacterial disease attacks can result in death of up to 50-100%, and reduce the quality of the fish meat of infected fish due to ulcers or wounds.聽Thus, consumers will not like it.聽Aeromonas hydrophila聽bacteria聽greatly affect freshwater fish farming business and often cause disease outbreaks with a high mortality rate of 80-100 percent in a short period of 1-2 weeks.聽The infectious disease caused by fungi and which is quite detrimental to aquaculture activities is聽Saprolegniasis聽caused by聽Saprolegnia听蝉辫.聽It often infects eggs and fresh fish that cause mass death in aquaculture.
Isolation and identification of聽Aeromonas hydrophila听补苍诲听Saprolegnia sp.聽were conducted to 20 catfish (Clarias gariepinus) obtained from 2 floating net cages.聽Isolation of聽Aeromonas hydrophila聽used isolation media Trypticase Soy Agar (TSA) and Saboraud Dextrose Agar (SDA) used for the isolation of聽Saprolegnia sp.聽The identification used conventional method including the examination of colony morphology, cell morphology, and biochemical tests.聽As supporting data, several parameters of water quality were measured around floating net cages, including temperature, pH,聽dissolved oxygen (DO) and ammonia levels.
Isolation of聽Aeromonas hydrophila听补苍诲听Saprolegnia听蝉辫.聽performed on 20 catfish with clinical symptoms, reddish wounds, flaky flippers and tails, and the presence of fine cotton-like threads on the surface of the catfish’s body.聽The results of isolation and identification showed 95 percent of catfish infected with聽Aeromonas hydrophila聽and 90 percent infected with聽Saprolegnia听蝉辫.
Aeromonas hydrophila聽is an opportunistic pathogen because it can only cause disease in weak fish populations or as a secondary infection when fish are infected with other diseases.聽These bacteria attack many catfish and it can infect fish of all sizes and cause death to reach 80 percent.聽Thus, resulting in enormous losses in the business of freshwater fish farming.
Fungal infection in fish is generally secondary infection that was preceded by bacterial infections, poor aquatic environments, parasitic infestations, high stocking densities, so the catfish (Clarias gariepinus) easily infected with聽Saprolegnia听蝉辫.聽The water quality measured during this research was, temperature 30聽o聽C, DO 4 mg / l, pH 6-7 and ammonia 1.0 mg / l.聽These results are still in normal category for fish farming activities, except the ammonite content that must be watched out because it is already within the borderline of tolerance limit.
Based on the results of the study it can be concluded that there was an infection of聽Aeromonas hydrophila听补苍诲听Saprolegnia听蝉辫.聽in most of the African catfish samples examined.聽It showed that the cultivation of African catfish in Bozem Moro Krembangan must be conducted with great vigilance to avoid greater losses of fish farmers around bozem.听(*)
Author: Rahayu Kusdarwati
The complete research results can be viewed in,
