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2 The contribution of marine shrimp to global aquaculture production

In the year 2000, total global aquaculture production was reported as 45.71 million metric tonnes (mmt) valued at US$56.47 thousand million. Over half of this was in the form of finfish (23.07 mmt or 50.4% of total production), followed by molluscs (10.73 mmt or 23.5%), aquatic plants (10.13 mmt or 22.2%), crustaceans (1.65 mmt or 3.6%), amphibians and reptiles (100 271 metric tonnes (mt) or 0.22%) and miscellaneous aquatic invertebrates (36 965 mt or 0.08%). Although crustaceans (a category comprised mainly of penaeid shrimps) represented only 3.6% of total production by weight, they comprised 16.6% of total global aquaculture by value in 2000.

Over half (54.9%) of global aquaculture production originated from marine or brackish coastal waters in 2000, as compared with 45.1% for freshwater aquaculture production. Although brackishwater production represented only 4.6% of total global aquaculture production by weight in 2000, it contributed 15.7% of total production by value. The main species groups reared in brackish water are high-value crustaceans and finfish (50.5% and 42.7%, respectively), while molluscs and aquatic plants dominate in marine waters (46.1% and 44.0%, respectively).

As in previous years, marine shrimp continued to dominate crustacean aquaculture, with shrimp production in 2000 reaching 1 087 111 mt (66.0% of global crustacean aquaculture production) and valued at US$6 880 068 900 (73.4% of total value). Aquaculture currently provides just over a quarter (26.1%) of total global shrimp landings. The main cultivated species are the giant tiger prawn (Penaeus monodon), the fleshy prawn (P. chinensis) and the whiteleg shrimp (P. (Litopenaeus) vannamei), these three species accounting for over 86% of total shrimp aquaculture production in 2000.

The growth in production of crustaceans has continued to be strong, increasing by 6.8% by weight from 1999, a rate slightly exceeding that for finfish (6.7%), molluscs (5.8%) and aquatic plants (6.1%). The growth of shrimp production, while still significant, has decreased to more modest levels over the last decade (averaging 5%) as compared to the double-digit growth rates observed during the seventies (23%) and eighties (25%).

2.1 Marine shrimp aquaculture production trends in Latin America

The countries of Latin America, although still relatively minor contributors to total world aquaculture production (1.9% of global production by weight, and 5.3% by value), have raised their output dramatically over the past 30 years, total aquaculture production increasing by over 714-fold by weight, from 1 221 mt in 1970 (0.03% of total global production) to 871 874 mt in 2000. Aquaculture continues to grow strongly in the region, increasing by a healthy 14.2% per year for the period 1990-2000, although this rate is considerably lower than the rapid increases seen in earlier decades (34.4% per year during the period 1970-1980 and 23.3% per year during 1980-1990). Overall growth during the period 1970-2000 averaged 24.5% per year.

The top ten cultured species by weight within the region in 2000 included Atlantic salmon (166 897 mt or 19.1%), whiteleg shrimp (139 264 mt or 16.0%), rainbow trout (97 479 mt or 11.2%), coho salmon (93 419 mt or 10.7%), tilapia (85 246 mt or 9.8%), common carp (62 241 mt or 7.1%), Gracilaria seaweed (33 642 mt or 3.8%), silver carp (30 000 mt or 3.4%), Chilean mussel (Mytilus chilensis) (23 477 mt or 2.7%) and the Peruvian calico scallop (Argopectin purpuratus) (21 295 mt or 2.4%) (FAO 2003).

The top country producers within the region in 2000 included Chile (425 058 mt or 48.7%), Brazil (153 558 mt or 17.6%), Ecuador (62 011 mt or 7.1%), Colombia (61 786 mt or 7.1%), Mexico (53 802 mt or 6.2%), Cuba (52 700 mt or 6.0%), Venezuela (12 830 mt or 1.5%), Costa Rica (9 708 mt or 1.1%), Honduras (8 542 mt or 1.0%) and Peru (6 812 mt or 0.8%).

By value, aquaculture production within the region has increased over eight-fold, from US$337 million in 1984 to US$2.98 thousand million in 2000 (representing 5.3% of the total global aquaculture production by value). The main species groups by value in 2000 were finfish (US$1.89 billion or 63.4%), crustaceans (US$0.94 billion or 31.5%) and molluscs (US$128 million or 4.3%), with the top cultured species being the whiteleg shrimp (US$848 million or 28.4%), Atlantic salmon (US$567 million or 19.0%), coho salmon (US$346 million or 11.6%), rainbow trout (US$291 million or 9.7%), tilapia (US$221 million or 7.4%), common carp (US$176 million or 5.9%), Peruvian calico scallop (US$93 million or 3.1%), penaeid shrimp (species not given) (US$77 million or 2.6%), cachama (Colossoma) (US$75 million or 2.5%) and silver carp (US$21 million or 0.7%).

2.2 Shrimp aquaculture in Latin America: the health issues

The shrimp farming industry in Latin America has developed and emerged as one of the major foreign exchange earners in the region. Initially, shrimp producers relied almost entirely on the capture of wild postlarvae (PL) in the estuaries and coastal areas where these are found naturally. Seasonal and annual variations in the catch of PL, however, led to the development of shrimp hatcheries where postlarval production could be undertaken in a more controlled manner. These hatcheries used wild broodstock caught by fishermen and supplied to the hatcheries.

The fluctuations in catches of both wild postlarvae and broodstock as a result of the El Niño phenomenon had a major impact on the development of hatcheries. In years when wild seed was abundant, low postlarval prices and a general perception that wild seed were stronger meant that many hatcheries encountered financial difficulties. In years when wild seed was scarce, on the other hand, hatchery-produced seed could be sold at a premium. Despite this, many hatcheries experienced problems due to the unpredictability of the market situation.

In recent years, disease, or more specifically, shrimp health concerns, has led to a revival of interest in hatchery-produced PL. Shrimp from some countries were widely believed to be less sensitive to Taura Syndrome Virus (TSV) than those from other areas, and this led to a lucrative cross-border trade in broodstock, nauplii and postlarvae in the region. Unfortunately, the arrival of the White Spot Syndrome Virus (WSSV) in the region in the late 1990s exposed the local hatchery operators to the possibility that the disease might be spread by such transfers if they were not conducted under appropriate controls and regulation.

At the same time, several producers had been experimenting with the breeding of survivors of TSV outbreaks in an attempt to develop lines of shrimp with greater resistance to the virus. The WSSV epidemic and the risk of vertical transmission accelerated this and led to a greater interest in genetics and breeding and a recognition that the dependence on wild sources of shrimp represented a significant disease risk. Hatchery operators reviewed their operations and focused on improving the biosecurity and health management of their production systems.

Now, most countries in Latin America have begun domestication and genetic selection programmes using pond-reared broodstock in maturation systems. This has been done in an attempt to stabilize predictability and improve the disease resistance and growth rates of their shrimp stocks. Initial efforts used broodstock from a variety of countries around the region in order to ensure a wide genetic variability in the stocks, but subsequent closure of most borders to import of live shrimp has curtailed this activity.

Most countries in the region are concentrating on the production of Specific Pathogen Resistant (SPR) or Specific Pathogen Tolerant (SPT) shrimp, selecting the best surviving (but not necessarily disease-free) animals from pond on-growing facilities and on-growing them further in various facilities before transfer to maturation systems. Specific Pathogen Free (SPF) shrimp (i.e. those certified free of one or more specific disease agents, and held throughout their lives in closed systems) have also been used, but with less frequency and when used, these animals have generally been brought in from isolated breeding centres in the United States.

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