THROUGH the use of formulated feeds and natural food, the survival rate of mud crab from zoea to megalopae and zoea to crab instar has significantly improved.
The improvement was realized under a project entitled “Improvement of Larval Rearing Protocol,” which is implemented by the Aquaculture Department, Southeast Asian Fisheries Development Center (SEAFDEC/AQD) and is led by Dr. Emilia T. Quinitio of the said agency.
The project is being funded by the Department of Science and Technology (DOST).
Data showed that the survival rate from zoea to megalopae has significantly improved from 3.75 percent to 22.5 percent, while the survival rate from zoea to crab instar has improved from 1.0-3.5 percent to 6 percent.
At present, basic hatchery technology has been developed in the country, however, a number of farms are still experiencing low survival rate during the megalopae stage due to Molt Death Syndrome (MDS).
It is a disease due to luminescent bacteria (Vibrio spp.).
It was learned that antibiotics are still being used to treat Vibrio spp., however, incorrect use of antibiotics can cause incomplete molting, deformities, slow growth, and even death.
Vibrio spp. is dominant in marine environments and can cause seafoodborne infections.
Furthermore, mud crab farmers in the country are experiencing lack of crab seeds for farming from the wild due to over exploitation.
To address over exploitation, the project aims to introduce the need to manage available resources and produce seed stocks in the hatchery for a sustainable mud crab industry.
This would also reduce the dependence of mud crab farmersregarding the sourcing of seed stock from the wild.
To reduce the occurrence of MDS, the zoea is fed with formulated feeds and natural food.
The use of natural food or rotifiers was reduced by as much as 50 percent.
For the natural food, minced fish or mussel can replace Artemia as feed during megalopae stage.
On the other hand, in terms of antibiotic use, the project compared the performance of antibiotics, antimicrobial, nitrofuran, disinfectant, therapeutant, and probiotics in larval rearing.
However, the project showed that the proper use of antibiotics, specifically furazolidone and oxytetracycline, is still the most effective way of preventing or treating diseases in mud crab.
To further equip the farm owners and different local government agencies, 22 collaborators and stakeholders were trained on the improved hatchery technology at the SEAFDEC/AQDin their respective sites.
Moreover, at least 13 mud crab hatcheries (9 are privately owned, 2 with the local government unit (LGU), 2 with state universities and colleges or SUCs) were established all over the country.
These hatcheries have been producing crablets that will help sustain the mud crab industry.
In Guindulman, Bohol, a prototype commercial-scale hatchery has already been turned over to the LGU.
This hatchery can produce about 40,000 crab instars per run.
The project is part of the National Mud Crab Science and Technology(S&T) Program, which is being monitored by the Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development of DOST (DOST-PCAARRD). (jaypeeyap@ymail.com/PN)
