Role of BBL Batam in Viral Nervous Necrosis (VNN) Virus Prevention in Grouper Fish

The Association of Marine Cultivation of Batam is a Central Technical Implementer Unit (Central UPT) of the Directorate General of Cultivated Fishery, Ministry of Marine and Fishery. This association is in charge of assisting cultivator activities within its territories, one of which is the Batam waters and its surroundings. The Batam Association of Marine Cultivation is established through the regulation of the Ministry of Marine and Fishery No. PER.10/MEN/2006, on 12 January 2006. Batam Association of Marine Cultivation has gone through historical transformation. It was originally established in 1986 under the name Marine Cultivation Station (Pinang Cape), which in 1990 changed into Sub-Association of Marine Cultivation (Riau Cape), and in 1994 changed again into Marine Cultivation Shop through the Regulation of the Ministry of Marine and Fishery No. 347/KPTS/OT.210/5/94, then in 2002 became Batam Marine Cultivation Shop located in Setoko Island, and  then became Batam Association of Marine Cultivation in 2006, and finally through the Regulation of the Ministry of Marine and Fishery No. 06/PERMEN-KP/2014 changed into Batam Association of Marine Cultivated Fishery, with the main task of performing test of applied technique and coordination, production, laboratory testing for fish health and environment, as well as technical assistance for marine cultivated fishery.

These tasks serve as a part of an investment which drives all follow-ups on cultivator activities. The Association of Marine Cultivated Fishery of Batam (BPBL Batam) conducts routine monitoring and sharing of cultivated fishery technology packages which includes counseling and vaccination and monitoring programs. This monitoring is intended to direct the cultivators to refer to the certification of proper fish hatchery methods (CPIB) and proper fish cultivation methods (CBIB), in order to have a maximized and sustainable cultivation activities. In addition, they also conduct socialization of chemical and drug usage, and give inputs on the prevention and countermeasures of fish diseases.

Marine cultivation will soon become the foothold for fishery business activities. Along with the increase in marine cultivation businesses, it is undeniable that the aquatic environment quality problems and fish diseases will also spread. Water quality is a crucial factor in the success of fishery cultivation businesses. This includes bacterial content within the waters because bacteria are one of the pollution indicators and the source of diseases. A programmed monitoring of aquatic bacterial content will obtain fluctuation pattern of aquatic bacterial content, which can be used to develop cultivation in Floating Marine Cages.

Treatment or medication is deemed as an ineffective solution. Aside from the costliness, the success rate is also difficult to predict. Not to mention the lack of time and skilled human resources, and the residue of such process can pollute the environment, create resistance against medication for certain diseases, and might be harmful for human health.

The attempt to put fish diseases under control is more emphasized on preventive attempts, that is, how to improve the fish immunity, improve environment quality, use disease-free seeds, and minimalize pathogen transfers. One of the preventive attempts which has become DJPB program as of lately is to improve the fish’s immune system through vaccination. Vaccines are weakened bacteria or viruses, introduced to the fish’s body to stimulate the growth and increase of the fish’s specific immune system.

In marine cultivation, one of the agents of infective diseases attacking seawater fish is the Viral Nervous Necrosis (VNN). VNN has infected more than 20 types of seawater fish, some of them are groupers, snappers, and snub-nose pompano. This disease can attack fish on any stage; larva, seed, rearing, and even parent fish, and can cause mass death. This virus often attacks the eye retina and brain, hence causing nervous system damage. VNN is also found to have attacked reproduction organs of seawater fish.

To avoid loss for cultivators, it is crucial to know and identify the symptoms of fish that are attacked by this disease in order to take immediate action to put it under control, both for prevention and medication. There are several clinical symptoms found on seawater fish infected with VNN; moving without direction, losing balance, swimming upside-down, swimming in circular motion (like a spiral), hyperactivity, jerking its head to the water surface sporadically, feeble, losing appetite, pale complexity, and death. The dead fish becomes the potential source of infection to other fish.

This virus is malignant and fast-spreading, making it difficult to contain. The effective way to treat VNN still has not been found, making this disease a grave problem in marine cultivation. However, there are several preventive actions against VNN attacks such as free VNN parent fish and larva selection, eggs disinfection, decreasing stress-inducing handling, decreasing number of larva/seed in one container, increasing water changing frequency (for tub rearing), biosecurity implementation, giving additives on feeds (vitamin C, multivitamin, immuno-stimulants), and VNN vaccination.

Role of BBL Batam in Viral Nervous Necrosis (VNN) Virus Prevention in Grouper Fish

Role of BBL Batam in Viral Nervous Necrosis (VNN) Virus Prevention in Grouper Fish

Role of BBL Batam in Viral Nervous Necrosis (VNN) Virus Prevention in Grouper Fish 2

Role of BBL Batam in Viral Nervous Necrosis (VNN) Virus Prevention in Grouper Fish 2

The most effective and efficient diseases control method is prevention. Preventing the emergence of diseases can be done though cultivation environment management, usage of proper feed with good quality, proper amount and delivery method. One of the preventive action taken is by creating immunity, both through vaccination and other immuno-stimulators. With just once or twice vaccination, the immune system usually lasts until the end of the fish rearing term. Vaccination in cultivated fishery is proven to give significant contribution towards increasing cultivated fishery production. The success of vaccination program is not only determined by the efficacy of the vaccine itself, but also the proper delivery technique and time.

Several requirements to meet before performing vaccination on fish are:

  1. The fish better be at least 3 weeks old.

The organs involved in antibody making system on fish younger than 3 weeks old has not completely formed.

  1. The fish health must be in optimum condition

A sick fish, for example due to parasitic pathogen infection, should not be vaccinated before the parasite is taken care of.

  1. The water temperature should be relatively warm (above 260C).

Based on experience, antibody response formed on vaccinated fish kept in water with temperature higher than 280C will be faster than that in lower temperature water.

  1. The water used to vaccinate and keep the fish must be free from any pollutant. Water with pollutants will inhibit the antibody making process in the fish’s body.

After meeting the said requirements, vaccination can be applied to the fish through several methods:

  1. Vaccine application through immersion

For small size fish in big numbers, it would be more efficient to apply vaccine through immersion. This is usually done in a container filled with a certain volume of water, mixed with certain vaccines, at to the recommended dose. The fish to be vaccinated are then put inside the solution for 15-30 minutes. During the vaccination process, it is best if the container is equipped with aeration and the fish density is not too high (100-200 grams fish per liter water).

  1. Vaccine application through feed

This technique is more suitable for fish already in rearing pond, or as a booster (re-vaccination). The dose used in this vaccination technique is as recommended. Applying vaccine through feed should be done in consecutively in 5-7 days.

  1. Vaccine application through injection

Vaccination through injection is more suitable for fish with relatively large size, not too big in number, and has higher value, such as parent fish. The advantage of vaccination through injection is, 100% of the vaccine gets absorbed by the fish’s body. There are two injection method; intra peritoneal (abdominal cavity) and intra muscular (muscles). The intra peritoneal method is more recommended due to the nature of the fish’s skin that does not easily heal or close up after being poked by the injection needle.

The one way to prevent fish diseases has been done by the Fish Health and Environment Testing Laboratory of BPBL Batam by providing vaccination services by certified professional vaccinators. Other vaccines available at BPBL Batam aside from VNN vaccine are vaccines for Aeromonas hydrophilla, Iridovirus, Vibrio, and Streptococcus iniae. Some of the types of fish being vaccinated are cantang grouper, brown-marbled grouper, orange-spotted grouper, and spotted-coral grouper.

Those vaccines have been distributed to some local fishery and marine agencies and socialized to cultivators within BPBL Batam territory. In the future, vaccination is expected to become one of the important measures taken by cultivators to ensure success in cultivation businesses.

Based on the cultivation diversity data, it is found that the cultivation system using floating marine cages with wood and polyethylene structures are the ones commonly used by the cultivator society for seawater fish commodity development. Research shows that polyethylene floating marine cage by Aquatec is more recommended because not only is this material environmentally friendly, but it is also durable under various environmental conditions, and costs less compared to other materials.

Since 2013 until now, BPBL Batam has been using the domestically made Aquatec floating marine cages to supply the need for 206 slots. Toha Tusihadi, the head of BPBL Batam, stated that Aquatec marine cagehas superiority in terms of material and structure strength, longer lifetime, durability against waves, and easier modification in the ways provided. The harvest yield from Aquatec marine cage usage is excellent, Toha added, and another important thing is the comfort and safety of cultivators when conducting activities on the marine cage. This product has been proven to withstand waves , and without any necessary repairs, work efficiency automatically improves. To ensure the sustainability of cultivation business, aside from Aquatec marine cage tools, mastery of technology and science is also crucial and can be obtained through cultivation trainings routinely held by local and central governments. In regards to grouper fish production by the Association of Marine Cultivated Fishery (BPBL) Batam in 2017, they are conducting revitalization program of Aquatec floating marine cage. The revitalization has been done in Bintan district, Batam city, and Natuna district, with the purpose of maximizing marine cage optimization for fish cultivators. The scope of this revitalization program includes providing seeds and production operational material incentives, as well as cultivation technical assistance. Through those programs, BPBL Batam is expected to play a role in improving the welfare and independence of the cultivators, improving the availability of animal protein for the people, and contributing to the country’s revenue.