Shrimp and tilapia production has accelerated in northeast Brazil in recent years, driven by increasing domestic demand and improvements in farming technology. Although early developments in aquaculture in the country date to the 1930s, with success of induced spawning of native freshwater fish, commercial aquaculture only started to expand in the 1990s with the introduction of Pacific whiteleg shrimp Litopenaeus vannamei and the Chitralada strain of Nile tilapia Oreochromis niloticus. In this period, aquaculture began to achieve industrial scale, with national production increasing from 87,674 t in 1997 to 278,129 t in 2003 (IBAMA 2008). In the succeeding ten years, production grew at an average annual rate of 6.5 percent, reaching 476,521 t in 2013 (IBGE 2014).

FIGURE 1. Annual production of farm-raised marine shrimp and tilapia in Brazil since 2003. Tilapia and shrimp production estimates are from FAO and ABCC (Brazilian Shrimp Farmers Association), respectively. Data for 2015 are estimates.

In 2014, tilapia and shrimp production was estimated to have reached 207,400 and 90,000 t, respectively (Fig. 1). This corresponded to more than 60 percent of the total harvested aquaculture volume in the country. Farming of both species is carried out predominantly in northeast Brazil, which accounts for 1/3 of the country’s total aquaculture production. The objectives of this article are to provide an overview of shrimp and tilapia culture in northeast Brazil and present the trends that have culminated in the recent phase of expansion.

History and Species

Northeast Brazil has over 3,000 km of coastline, with tropical temperatures of 26-28 C throughout the year. Coastal land in rural areas is widely available and still poorly explored. Much of the economy in these areas relies on tourism or primary production activities such as artisanal fisheries, salt production, aquaculture and rainfed or irrigated agriculture. In upper states of the northeast, towards the Amazon, water is abundant and large-scale soybean and cattle production are conducted. However, in much of the region, a semi-arid climate prevails. In dry inland areas, there are man-made reservoirs to mitigate the effects of scarce rainfall and extended droughts. Constructed dams are primarily used to store freshwater for human and animal consumption, but also to serve for crop irrigation, fisheries, aquaculture and other economic activities. With a good ground transportation and communications infrastructure, the region has good access to the extensive agro-industrial base and the major consumer markets in Brazil. These conditions have long been considered ideal for aquaculture development.

However, it was only in 1973 that a milestone of shrimp farming took place in Brazil when the "Shrimp Project" was created in Rio Grande do Norte state. Over the following two decades, farmers experimented with several different species, including the Kuruma shrimp Marsupenaeus japonicus and the native Southern brown shrimp Farfantepenaeus subtilis. Consolidation of commercial culture came in the mid-1990s when industrially compounded aquafeeds and hatchery-produced post-larvae of L. vannamei became available.

Tilapia (Congo tilapia Tilapia rendalli) was first introduced in northeast Brazil in 1957. In 1971, the federal government introduced Nile tilapia Oreochomis niloticus and Zanzibar tilapia Oreochromis urolepis hornorum as part of a breeding program. Starting in the 1980s, several tilapia strains were introduced. However, in the mid-1990s, feed-based tilapia aquaculture in small-volume cages started to develop in the region with red strains and the Thai-Chitralada Nile strain (Fig. 2). Today the Chitralada strain dominates production in the northeast, although farmers continue experimenting with other strains with narrow success.

Shrimp Aquaculture
Farm Performance

Between 1998 and 2003, shrimp farmers in northeast Brazil increased annual yields from an average of 1,678 kg/ha to 6,084 kg/ha (Nunes et al. 2011). This was achieved through successive incremental increases in shrimp stocking density, use of paddlewheel aeration (Fig. 3) and the delivery of feeds exclusively in feeding trays for strict control over feed inputs. In 2003, intensification was disrupted by outbreaks of Infectious Myonecrosis Virus (IMNV) disease. Today shrimp stocking densities can range from 30 to as many as 70 PLs/m2 but can be 15 PLs/m2 or less in ponds without artificial aeration.

However, annual yields continue to increase. This has been achieved by faster production cycles and shorter intervals between crops. The average crop duration is 70 days, with yields of 800 to 4,000 kg/ha/crop and three or more crops per year. Annual yields depend on shrimp survival, growth rates and the targeted market size of the shrimp. The farm’s ability to mechanically aerate pond water and to continually apply bioremediation products to water and soil have also been keys to improved results.

Nursery Systems

Shrimp farming in Brazil has been traditionally carried out in a two-stage cycle. The approach usually involves acclimating post-larvae (PL10) from 5 to 15 days in nursery tanks before transfer to ponds. Nursery tanks are usually round and constructed of concrete, fiberglass or flexible PVC laminate. These tanks are usually 1.2 m high with volumes of 50-80 m3. They are configured with a central drain and continuously aerated with diffusers served by air blowers (Fig. 4A).

Similar to some other countries in Latin America, shrimp farmers prolong the nursery phase to stock larger and more resistant PLs in ponds, from 50 to 70 PLs/g to 4 to 6 PLs/g (Figs. 4A and 4C). This has been attempted by 1) installing skimmers in nursery tanks to remove excess nitrogen and suspended organic matter in water, 2) controlling water temperature and phytoplankton blooms by shading tanks with black plastic, 3) size-grading post-larvae prior to stocking, 4) shifting from starter to post-larval diets, which are more nutrient-dense and digestible and 5) adding an additional culture phase after the nursery using lined ponds near grow-out ponds (Figs. 4D and 4E). So far, this has allowed farmers to shorten grow-out cycles by 15 days or more and improve final survival by 20 percent.

Read the rest of this article in the June 2015 issue of World Aquaculture Magazine here