Big loss of young fish
Mr. Kim Hoang Thanh, director of the Fisheries Sub-department of Kien Giang, confirmed that in Hon Tre Island Township (Kien Hai Island District), there was a phenomenon of fish farming in fishermen’s cages, with large numbers dying. According to initial records, it was a caged fish from a fishing household, but there are no mass die-offs of farmed fish. The reason may be that the quality of the seed is not guaranteed, the breeding technique is not good, because the farmed fish of other households nearby are still developing normally, the environmental indicators and water quality are stable.
Since February 2023, there have been isolated deaths of fish reared in cages and rafts by fishing households in Hon Tre island community, particularly Vo Thi Tham’s household, which suffered major damage. Picture: Trung Chanh.
According to the report by the Ministry of Agriculture and Rural Development of Kien Hai District, there are currently 43 households engaged in marine aquaculture in the entire Hon Tre Municipality, with 122 rafts and 292 cages. The main breeders of cobia, grouper, red snapper, yellowfin pompano and string oysters, green mussels… On February 17, people informed the functional industry that fish, oysters and mussels were being farmed in cages. In Hon Tre, there was a mass die-off unknown cause.
Faced with this situation, the Kien Hai District People’s Committee has ordered the district Ministry of Agriculture and Rural Development to dispatch technical personnel to monitor the situation on the fish rafts. The research shows that the color and salinity of the water source in the area where the cages are anchored have remained fairly stable from early 2023 until now. Regarding the situation of caged fish, there has been major damage mainly by fisherman Vo Thi Tham, while farmed fish from many other households in Hon Tre commune have remained stable.
Ms. Vo Thi Tham’s household has invested in 32 cages and keeps some main species of Cobia, Grouper, Red Snapper and Yellowfin Pompano. The subjects that died at a high rate were groupers that had just been stocked for 15-40 days. From August 2022 to date, Ms. Tham has purchased and released 3 batches of grouper juveniles totaling 30,000 fish (phase 1: 10,000 fish, phase 2: 14,000 fish and phase 3: 6,000 fish) from a seed production facility in Khanh Hoa Province . Through the investigation, it was found that the rate of dead and lost fish sticks is up to 80-90%. Only phase 1 and phase 3 died 100%.
Initial examination showed that grouper fingerstalls showed signs of illness, sluggish swimming at the corners of the cages and sores on the front of the head. In the intestines, the ball is slightly enlarged, the liver becomes yellow, opaque and uneven. At present, the Kien Giang Animal Husbandry and Veterinary Medicine Department has dispatched technical personnel to check the exact cause of death of farmed fish and take samples.
Spontaneous rearing is not properly planned
According to the Kien Hai District People’s Committee, the anchorages for cages and rafts of the fishing households are currently located in the storm protection area, not in the district’s planned fish cage farming area. In this area, the water source is easily polluted, the water from residential areas overflows, and the water flows from the mainland, so the fish die easily. The district authorities of Kien Hai have warned many times, but households are still deliberately raising spontaneously, so there is often a phenomenon of isolated and prolonged death of farmed fish.
The area where the cages and rafts of Hon Tre’s fishing households are anchored is currently within the storm sanctuary area, not in the area planned for the district’s fish cage farming. The water source is slightly polluted, which leads to fish farming. died. Picture: Trung Chanh.
Interviews with the technical staff revealed that there were many decomposing water hyacinths around and in the cages. Dead farmed fish are not collected and destroyed by households, but left in cages and also in the process of decomposition. Due to the large number of fish farms, farmers do not have time to bathe the fish regularly.
Besides the death of caged fish, since the beginning of February 2023 until now, there has also been a phenomenon of oysters and green mussels in Hon Tre, farmers scattered 90% died for a long time. Watch the actual oysters hanging from ropes, green clams, the dead ones are on the outside of the hanging beams and those inside are not dead.
According to initial assessments, the cause of the death of oysters and mussels may lie in the feed. Since these two objects are species that live in groups and are passive filter feeders on the substrate, if a food source is present, they will be tolerated by the body. The outer ones tolerate first and the amount of food is greater than the inner ones, so the outer ones die first when they encounter a harmful food source.