Expert topic: Banana shrimp
by Rebecca Sherratt, Features Editor, International Aquafeed
Banana shrimp (Fenneropenaeus merguiensis) are a variety of shrimp commonly found in the Indo-West Pacific oceans which are farmed extensively in in both Australia and South-East Asia. The countries which are most well-known for their banana shrimp production include Vietnam, Indonesia, the Philippines, Thailand, Singapore and Malaysia.
This sub-species of shrimp has been harvested for aquaculture in steadily increasing rates, 50,393 tonnes being harvested in 2000 for aquaculture purposes, which hit its peak in 2006 at 96,633t. In 2007 onwards, production dropped off significantly, 2016 only producing 24,681t of banana shrimp specifically for the aquaculture industry.
This unique kind of shrimp is renowned for its sweet, light flavour and is suited very well for spicy dishes. They are traditionally barbecued or shallow fried. There are two varieties, the redleg banana prawns and white banana prawns, which can be distinguished by their colours. Redleg banana prawns are the more expensive and desirable varieties.
Despite the wide variety of countries which farm banana shrimp, they are still considered a minor farmable species in the industry, world production of the banana shrimp being only roughly eight percent of that of major farmable species, much less than the more prominent shrimp farmed in the sector, such as the Whiteleg prawn (Penaeus vannamei).
Another difficulty that comes with farming banana shrimp is the perception of their high mortality rates when raised in semi-intensive ponds, but these rates have not been studied extensively to conclude that banana shrimp are especially tricky for farmers to raise. Despite this, in coming years it has been noted that prawn post larvae are especially difficult to come across, which has not assisted in the farming of this unique species.
Yet there still remain many success stories for the banana prawn. Australia especially have reported survival rates of over 80 percent in their banana shrimp using semi-intensive and intensive farming techniques and, as technology evolves, these decapods are expected to become a recognisable face in the aquaculture sector.
Farming banana shrimp
Australia typically farm banana shrimp in intensive and semi-intensive ponds, whereas Asia often make use of extensive ponds with natural seeding. Post larvae or juvenile banana shrimp are commonly caught with tidal currents in large extensive ponds in South-East Asia and kept in these ponds for several months, before being harvested. Wild seeds used to be commonly collected and sold on, but overfishing has limited the occurrence of wild seed being readily available.
Spawners can be obtained from the wild or developed via induced maturation in hatcheries. Peak spawning seasons for banana shrimp are March, April, July and August in Asia. Maturation is sometimes induced in hatchery shrimp via eyestalk ablation, wherein female banana shrimp eyestalks are unilaterally ablated to stimulate endocrine activity, growing back in approximately six months. Mature banana shrimp males should be 140mm or larger, whilst females should be typically 150mm or larger.
Hatchery tanks for banana shrimp are usually between two-and-five tonnes in capacity, which rear larvae from the nauplius stage to the mysis stage. pH is kept at approximately 8.2. Nauplius are not given feed until they reach the protozoa stage, wherein they are supplied with a mixed culture of diatoms (single-celled algae), mainly Chaetoceros spp. or Skeletonema spp.
Shrimp are fed artemia nauplii, whilst post-larva is fed minced mantis shrimp powder or mussel meal at particle sizes of 200-1000µm for the first 20 days of the mysis stage. Once this stage is passed, the banana shrimp can be directly transferred to grow-out ponds.
The traditional extensive systems for banana shrimp farming is different, this method used primarily in Asia. After stocking with seeds from incoming tidal water, paddy fields house the seeds during November through to April. On average, each harvest takes 150-180 days to complete.
Semi-intensive production features ponds 1-1.5m deep at 0.2-2ha. Stock usually range from 20-25 pl/m2 using seeds from hatcheries. Fertilisers assist in growing natural feeds, whilst supplementary feeds are supplied to ponds four-to five times a day. One harvest may take 100-150 days.
In intensive banana shrimp farming, ponds are much smaller at between 0.1-1ha and stocking density is higher (50-100 pl/m2). Culture periods last 120-140 days.
Bringing sustainability to the shrimp sector
One reason a booming banana shrimp industry would prove especially advantageous is reducing the pressures on other more heavily farmed shrimp species. Giant tiger prawns (Penaeus monodon), Chinese white shrimp (Fenneropenaeus chinensis) and Whiteleg prawns (P. vannamei) are all now subject to sustainability concerns due to the excessive quantities in which they are farmed.
This could prove, admittedly, somewhat challenging in the initial stages, as banana prawns grow slower than the more popular varieties of prawn and have shorter life cycles, but research suggests that banana prawns provide a consistent and regular production of post larvae, ensuring a low cost of broodstock, ease in larval rearing and low feed costs.
If banana shrimp make a bigger splash in the market, this will provide other species with the opportunity to recover and stabilise their numbers.