The best way to describe polyculture is as the simultaneous cultivation of multiple crop species on the same plot and same time. Adopting polyculture is an attempt to replicate the diversity present in natural ecosystems. In a specific aquaculture setting, it refers to the production system of two or more fish species.

Potentiality of shrimp polyculture:

White fish polyculture combined with shrimp polyculture offers Bangladesh’s economy a lot of promise. Currently, shrimp farmers in the nation’s coastal regions employ shrimp polyculture technology to the greatest extent. Shrimp-fish polyculture is thought to be a technique that can reduce shrimp infections and address environmental pollution. This has the potential to support the aquaculture sector’s sustainable growth in prawn farming.

The majority of Bangladesh’s coastal aquaculture is made up of shrimp and prawn farming in ghers. “Ghers” are elevated dykes on low-lying rice fields that are modified for the seasonal production of fish, prawns and other aquatic items. Shrimp or prawn fries are added to water that has been submerged and logged for an extended period of time in a gher farming technique. The maturation and commercial size of prawns and prawns takes three to six months. Aquaculture species’ productivity can be increased by prawn polyculture without negatively impacting the current environmental conditions. This will raise the pace at which the harvested organisms convert nutrients into energy and increase the overall biomass production and water quality. It will also establish a dynamic bacterial community structure.

However, unplanned shrimp cultivation sometimes diversely affects the soil and agriculture yields, ecology, biodiversity and sustainability of agriculture in the coastal regions of Bangladesh. The extra salt that is added to the field increases the level of soil salinity. Therefore, this saline water degrades the soil quality of fresh lands that adversely affect the local vegetation, plants and trees, crops, fishes, livestock, environment, ecology, and population health and disease patterns. In low-saline coastal areas, shrimp polyculture with other species can be used to reduce the problems currently associated with shrimp farming in Bangladesh. This is because species diversity can reduce the impact of discharged effluent and absorb the majority of wastes generated from shrimp monoculture. Low salinity prawn polyculture helps prevent diseases brought on by Ich (Cryptocaryon irritans), external nematodes, and most ectoparasites and protozoa parasites that cannot survive at low salinity for an extended period of time, but it can also lead to an increase in a variety of other parasites and diseases.

A promising tactic for the long-term growth of prawn aquaculture is shrimp-fish polyculture. It may lead to higher animal yields, faster rate of nutrient conversion, and ultimately better water quality. It may also help avoid diseases that affect prawns. When combined, shrimp-fish polyculture can lessen its negative effects on the environment and improve public perception of the aquaculture sector.

Farhana Islam
Agriculturist, Researcher
Fisheries Resource Management, CVASU

The post The tremendous potentiality of shrimp fish polyculture system for aquaculture industry appeared first on Seafood Network BD.

What is the benefits of polyculture system?

When compared to fish raised in monoculture, polyculture offers significant potential for boosting fish production per unit area. Combinations of several species in polyculture systems successfully contribute to enhancing the pond habitat. In the majority of tropical manure-fed ponds, algae blooming is widespread. Phytoplanktophagus Silver carp can be stocked at the right density to prevent certain types of algal blooms. The macrovegetation-eating habits of grass carp, on the other hand, help to regulate the macrophyte population, and they also contribute more partially digested excreta, which is fed to the coprophagous common carp, a bottom-dwelling species. The bottom-dwelling mrigal, common, and mirror carp move the bottom mud in search of food while aiding in the re-suspension of bottom nutrients to water. Such activity by bottom creatures also aerates the sediment at the bottom. All of these factors imply that polyculture is the best option for fish culture in tropical ponds that cannot be drained.

Drawbacks of polyculture:

Even though there are obvious differences between food preferences under natural circumstances, it is still too early to determine the relevance of these feeding differences when stocks are fed with formulated feeds. Adopting supplementary feeding in an economical manner is not very simple. To maintain the best possible balance of the species, farmers must have specialised knowledge and work to generate or buy the right quantity of seed stocks of the different species they have chosen. Sex, age, and size are less under your control. It is harder to keep track of this. Consumer acceptance of various species differs in many cases and across most regions. Additionally, finding markets for other species, such as grass carp, pangas, and silver carp, has proven difficult.

Compatible fish species for Polyculture system:

The first crucial step when developing a polyculture is choosing the appropriate species. You must choose a variety of fish with various eating preferences. We have to be sure to choose the right kind of fish for each level of our pond. You must choose at least one fish species that feeds at one of the three levels. Planktivorous fish will be present at the surface. Fish species that are fed by omnivore to macro vegetation will be used at the medium stage. Bottom-feeding benthic/detritivorous species.

• Planktivorous fish: Catla, Grass carp, Big head carp, Silver carp
• Omnivorous fish: Rohu, Common carp, Tilapia
• Detritivorous fish: Mrigal, Calbasu, Grey mullets, Black carp, Mud carp, Shrimp

Farhana Islam
Agriculturist, Researcher
Fisheries Resource Management, CVASU

The post What is Polyculture system and benefits appeared first on Seafood Network BD.