Aquaculture Presents New Opportunities for Puerto Rican Farmers

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1 Aquaculture Presents New Opportunities for Puerto Rican Farmers By Michael V. McGee, Ph.D. Caribe Fisheries Inc. Lajas, PR Over the last twenty-five years the fastest growing sector of agriculture world-wide has been aquaculture. Simply put, aquaculture is the propagation and production of aquatic species under controlled conditions. Similar to traditional agriculture in many respects aquaculture farms produced nearly 46,000,000 metric tons of products in Today a large percentage of fresh water fish species consumed for food including Tilapia, catfish, carp, trout, and pacu, are produced by farmers. An increasing percentage of saltwater species including oysters, clams, shrimp and salmon are also farmraised. New species and production techniques are continually being developed and evaluated. While richer nations have often been leaders in terms of education and technology, developing countries especially in tropical regions have in many cases received the most economic benefit from the blue revolution, as the modern aquaculture industry is sometimes called. Throughout Latin America and the Caribbean aquaculture has brought new opportunities and economic growth to farmers, rural communities and national economies. Aquaculture products provide food for local consumption and high value products such as shrimp are a source of important export revenues. In Puerto Rico many opportunities exist for aquaculture development however to date the industry has not become established or even recognized in relation to its potential. As a tropical island with adequate land and water resources and an agricultural sector in need of innovations Puerto Rico presents an ideal climate for aquaculture development. In the coastal plains and valleys where sugar cane was traditionally grown and is now largely abandoned, farmers need new crops and sources of revenue to sustain their farm enterprises. In other areas, land owners may seek opportunities to produce fish or shrimp

2 crops for local or home consumption. As compared to many other Latin American and Caribbean nations Puerto Rico lags behind in aquaculture but has considerable infrastructure and markets, as well as sources of financing, which can facilitate establishment of a successful new industry. Farmers who become interested in aquaculture need to invest first in learning about the species and techniques required to establish an aquaculture project. Tilapia and the freshwater prawn Macrobrachium rosenbergii have been cultured in Puerto Rico at the University of Puerto Rico Agricultural Experiment Station for over 25 years however the industry has not become established commercially and to date few Puerto Ricans are trained in the science. These species are easily grown but each presents specific management challenges which must be understood. Tilapia, are freshwater fish native to Africa which have been introduced worldwide for aquaculture. Fast growing and tolerant of crowding and poor water quality the Tilapia is often cited as the fish of choice for the beginning aquafarmer. In truth however, production of large- sized Tilapia in ponds is complicated by their rapid and prolific reproduction which results in overpopulation of the pond environment and excessive numbers of undersized and undesirable fish. Successful Tilapia production requires that the farmer establish management procedures which effectively limit unwanted reproduction. To do this, farmers must stock only male fish or introduce another fish species which will prey on the small Tilapia and control their numbers. As an alternative Tilapia may be grown in floating cages in ponds or produced intensively in tanks. All of these techniques are successful when applied with the proper preparation and understanding on the part of the fish culturist. The freshwater prawn Macrobrachium is another long established aquaculture species in Puerto Rico and is easily produced in ponds if proper management guidelines are followed. Although prawns command a high price it is not possible to overcrowd them in ponds and hence production of over 2,500 lbs/acre/year is difficult to achieve. In addition prawns do not grow equally hence harvest of the larger most desirable sizes requires regular harvests over several months. Prawns are sensitive to low dissolved oxygen and can die if pond oxygen levels fall below 2 mg/l. To ensure successful prawn production at profitable levels aeration of the pond environment is normally required. In this case the farmer must be concerned that the cost of aeration does not eliminate the profits from the prawn

3 production. Efficient management of pond populations of prawns is one of the most difficult challenges for the producer wishing to optimize production and profits. Beyond these species which are well known in Puerto Rico new species are now available locally which hold great potential for successful aquaculture production. Fish of the genus Colossoma known also as pacu or cachama are native to the Amazon River basin in northern South America. These fish are widely cultured throughout tropical regions of South and Central America. Pacu grow quickly to a large size and are well accepted as a food and sport fish. These fish are tolerant of poor water quality and crowding and can be stocked at high densities in ponds. In polyculture with Tilapia they appear to reduce unwanted reproduction. Pacu themselves cannot reproduce in the pond environment. Another new species of considerable interest for Puerto Rico is the basa catfish of the genus Pangasius. This tropical catfish is native to Southeast Asia where it is one of the most important aquaculture species in the region. These fish grow quickly under intensive pond conditions and can reach sizes of over 2 lbs in one year. They are very tolerant of poor water quality and also adapt well to cage culture. These fish are also useful in controlling Tilapia reproduction. Basa catfish have been well received as a frozen filet product on the world market. Within two years exports from Vietnam took over 20% of the United States catfish filet market and forced the US Congress to enact legislation to protect the domestic catfish industry. Marine species also hold great potential for development in Puerto Rico. For more than 15 years a Taiwanese company has operated a highly successful marine shrimp farm near Dorado. In recent years new technology developed for marine shrimp of the genus Litopenaeus has indicated that these shrimp can be grown in very low salinity water far from coastal areas. This concept of inland shrimp farming has tremendous implications for salt affected areas such as parts of the Lajas Valley where traditional crops are not possible. Clams and oysters are widely cultured and hold good potential for development in Puerto Rico. Areas where wild clams and oysters are presently harvested would be ideal sites to designate for this use. Beyond these well established species, much potential exists for other marine fish species such as snappers and groupers which are favorites of Puerto Rican consumers. The technology for production of these species exists but further work is required to demonstrate the commercial potential in the Caribbean.

4 Beyond the need for knowledge of the species of interest and its economic viability an aquaculturist must develop an understanding of the culture environment. Unlike terrestrial crops and livestock, aquaculture species live in an aquatic world which has characteristics and critical variables much different than those which we are accustomed to deal with. Dissolved oxygen is often a primary limiting factor to production and insufficient quantities can lead to rapid and catastrophic crop loss. Alkalinity, hardness, salinity, ph, ammonia, nitrite and other chemical and physical variables all may have vital and critical impacts on the cultured species. An aquaculturist who does not learn the importance or relevance of these variables in the beginning will likely have to learn them later. Typically most aquaculture species are produced in ponds. Ponds for aquaculture generally range in size from 0.25 to 10 acres and 0.5 to 2 acre ponds are common. Water supply should be of good quality and from a dependable source. Common sources are irrigation canals or wells and in some cases springs or rivers. Aquaculture ponds should have flat clean bottoms which slope to a drain. Ideally each pond should have an independent drain to facilitate water exchange and harvests. If ponds cannot be drained or are intended primarily for another use such as crop irrigation, fish can be grown in cages suspended in the ponds. Many beginning aquaculturists become intrigued by the possibility of growing fish intensively in tanks using a recirculation system. Although potential does exist for systems of this sort it must be emphasized that operational costs are higher and technical management more complex. As in all of the opportunities discussed in this article adequate preparation is required prior to investing in or constructing an intensive fish production system. This short overview is intended to get more farmers in Puerto Rico thinking about aquaculture and to briefly introduce some of the opportunities and potential this new industry brings. At the same time I have emphasized the need for proper preparation and education prior to investing. For farmers or investors who need assistance with an aquaculture project Caribe Fisheries Inc. provides a wide range of supplies and services. Established in 1989 Caribe Fisheries Inc. has been in successful operation as an aquaculture business for 14 years. Located in the Lajas Valley, Caribe Fisheries Inc. specializes in the production of fingerlings of food fish species and juvenile freshwater prawns in addition to producing a wide range of tropical ornamental fish species. Caribe Fisheries Inc. will assist farmers

5 with the design and development of aquaculture projects. The owner and staff of Caribe Fisheries have over 40 years of practical experience in aquaculture as well as professional and academic qualifications. We are dedicated to developing aquaculture and to creating a successful industry which can be sustained, thereby contributing to the growing diversity of agriculture in Puerto Rico.