Sustainable and Environmentally Friendly Culture Systems

Kevin Fitzsimmons, Ph.D.

Environmental Research Lab

Department of Soil, Water and Environmental Science

University of Arizona

Introduction

• Aquaculture is the fastest growing sector in production agriculture in the US and worldwide.

• Aquatic plants and animals are only now being domesticated.

• US industry is dwarfed by aquaculture in Asia, Europe and Latin America.

Environmental constraints on conventional shrimp culture

• Loss of mangroves and other coastal vegetation.

Environmental constraints on conventional shrimp culture

• Effluents and nutrient enrichment

• Impacts (real and imagined) on wild shrimp and other species (diseases, exotic species, genetic contamination).

• Changes in estuarine flow patterns.

Introduction

• Sustainable aquaculture is not a new concept.• Fish/rice, fish/vegetable, fish/duck and fish/pig

systems in Eastern Asia are thousands of years old.

• These highly efficient systems and the healthy diets they produce are the primary reason for the high populations in East and South Asia.

Introduction• However, many of these sustainable systems

depend on animal and historically, on human wastes as fertilizer.

• In many countries, use of animal wastes to fertilize fish systems will not be accepted.

• Multiple-use of water is an important aspect of sustainable aquaculture systems.

• Fish effluents must be used as input to another crop.

Introduction

• Irrigated agriculture has been a central part of the “Green Revolution”.

• Irrigation should be part of the “Blue Revolution”.

• Millions of hectares are irrigated worldwide.• Irrigation water is ideally suited for

aquaculture and aquaculture effluent is ideal for plant crops.

Introduction

• Water is already controlled.

• Either pumped from groundwater or diverted from natural or man-made watercourses.

• Reservoirs and canal structures are ideal locations for fish culture.

• Water is usually of high quality, often from the same source as drinking water.

• Most water fit for drinking and/or agriculture, is fine for fish.

Cages in Irrigation Reservoirs100 m2 cages in Philippines

Pro’s and con’s of cages in reservoirs

• Can work w/ large cages

• Good water quality

• Need boat to steal fish

• Can grow large quantities

• Easy to lose lots of fish

• Subject to outside pollution

• Easy access by public

• Capital & permitting expenses

Production in Main Canals

Main Canals (3000 cfs)

Pro’s and con’s of cages in main canals

• Good water motion and quality

• Easy access

• One management entity

• Water interruptions are rare and/or scheduled

• Management may not be interested

• Water motion may be excessive

• Poaching• High cost of cages• Water may be

interrupted

Modified delivery canalsIn-line or parallel raceways for fish production

Raceways in Arizona

Raceways in Mexico

Pro’s and con’s of modified delivery canals

• Better control of water and access

• Adjustable flow rates

• Can modify production system

• Higher costs

• Less dilution capability

• Difficult to dry down

• May be on irrigation district land, not on-farm

Diversions from well or delivery canal

Tanks in Arizona

Ponds in Costa Rica

On farm storage ponds• Growing in ponds or cages in ponds.

Farm pond in Brazil Reservoir pond in Arizona

Species produced

• Shrimp, trout, tilapia, catfish, grass carp and many other species can be grown in irrigation water.

Aquaculture Sustainability Research Projects

• Effluent management

• Integration of aquaculture and agriculture

• Shrimp production

• Tilapia production

Research - Effluent management

• US - EPA is in process of regulating all US aquaculture wastes

• Field crop irrigation is accepted as a “Best Management Practice” by several states

• World Bank, Global Aquaculture Alliance and others promote multiple use.

Pond culture to cotton irrigation

Research Projects - Integration

of aquaculture and agriculture • Irrigate cotton crops with water from

catfish ponds and well water

• Irrigate cotton crops with water from tilapia tanks and well water

• Measure differences in water quality, nitrogen requirements & cotton yield

• Determine economic impact

Research Projects - Integration of aquaculture and agriculture

• First use of water for extensive pond culture.

• Pond filled with well water.• Catfish stocked at 7,000 kg/ha• Second use to irrigate and fertilize cotton.• Replicated plots irrigated with well water

and pond water.

Results - Integration of aquaculture and agriculture

• Water pH reduced from 8.3 to 8.0

• Added 19.7 kg/ha N to 45 kg/ha used in standard fertilization schedule.

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Results - Integration of aquaculture and agriculture

• Contributed 2.6 kg/ha P to crop.

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Results - Integration of aquaculture and agriculture:

• No significant difference in cotton yield.

• Need additional trials with less chemical fertilizer application.

• No negative impacts on soils.

• Split cost of water results in savings to farmers ($120/ha).

Results - Integration of aquaculture and agriculture:

• Other expected benefits (more experiments needed to confirm & quantify):1. Slow release of organic wastes as fertilizer.2. Less chance of nitrates migrating to groundwater.3. Increase soil tilth (soil moisture capacity).

Sustainable Shrimp Systems• Shrimp• Tilapia• Seaweed• Halophytes

Puerto Peñasco,Mexico

Use of inland saline waters for “marine” species and irrigation• “Low quality” groundwater, saline intrusion

along seacoasts in Mexico, Peru and Ecuador

• Much of this water is low grade geothermal.

• Some has been used for conventional irrigation in the past.

• Penaeid shrimp, redfish, oysters, seaweeds have been grown in-land.

Low salinity inland shrimp culture

• Florida, Harbor Branch Oceanographic

• Mexico, Colima; Aquagranjas

• Thailand, multiple sites

• India, Andhra Pradesh

• Texas: multiple farms and Texas A&M

• Arizona: Gila Bend, Hyder, & Aztec Farms

• University of Arizona

Inland shrimp production• All types of systems can be

integrated with irrigation.

Extensive ponds

Intensive ponds

Intensive raceways

Source groundwater

• Low (1-2 ppt or 1000 -2000 ppm TDS).

• Med (3-5 ppt or 3000 - 5000 ppm TDS)

• Low can be used on conventional crops.

• Medium salinity effluent constitutes a disposal problem.

• Medium salinity effluent can be used for algae culture, seaweeds, halophyte crops.

Shrimp in inland waters• Low salinity can be used on certain

conventional crops with proper cultivation techniques.

Sorghum Olives

Research Project - Shrimp effluent on crops

• Wood Brothers Farm in Gila Bend, AZ• 12 hectares of ponds, one greenhouse• Stocking Litopenaeus vannamei

– 35 shrimp/m2 @ 0.4 g

• Feed - Rangen• Aeration

– Paddlewheels– Diffusers

RESULTSGila Bend, Low salinity

• Water exchange: 10-15%

• Survival 70%

• Harvest after 95 days, @ 21 g

• Yield– 7,500 kg/ha– 12 ha of ponds

• Effluent used on olives, sorghum, cotton

RESULTSGila Bend, Low salinity

• Preliminary data (summer 2000):

• 0.07 mg/L NH3, 0.321 mg/L NO2, 21.2 mg/L NO3, 0.17 mg/L total P

• Fertilizer value about 43 kg/ha N and 0.34 kg/ha P

RESULTSGila Bend, Low salinity

• Algae bloom– more characteristic of freshwater– nutritional value for shrimp needs to be

studied

• Problems– Hemocytic enteritis– Gill fouling

RESULTS Aztec Farm, Medium salinity

• Stocking L. vannamei, L. stylirostris– 5 to 10 shrimp/m2 @ PL 20

• Feed - Rangen

• Water exchange: limited

• Aeration:none

RESULTS 1999Aztec, Medium salinity

• Survival L. vannamei, L. stylirostris– 10 to 30%

• 3 grams per week at one point• Harvest after 120 days, @ 10 - 20 g• Yield - 20,000 kg

– average = 1,000 kg/ha– 20 ha of ponds – 2000 results are reported to be better

Conclusions• Shrimp can be produced in low salinity groundwater.• Commercial quantities can be produced.• Low salinity effluent waters can be used for

conventional field crops.• Medium salinity effluent can be used for halophyte

crops.• Sustainability will not be demonstrated until salt levels

in soils are tested after several years of irrigation.

Conclusions

• Markets are prepared to pay a premium for fresh, locally grown shrimp.

• Profitability will be determined if more crop cycles can be completed without significant losses due to disease or other environmental conditions.

Shrimp in the desert:Pro’s and cons of integrated farms

• May be more sustainable than coastal sites

• Uses abundant resource

• Benefits rural areas

• May not be sustainable

• May import exotic species and diseases

Shrimp in coastal locations - Sustainable Systems

• Effluents can be used for halophytes, seaweeds or reconstructed mangroves.

• Halophytes have agronomic potential

• Seaweeds are effective biofilters absorbing nutrients.

• Mangroves are needed for restoration and many farms are required to provide mitigation.

Shrimp and irrigation of Halophytes

• Many families of plants have halophytic representatives.

• Grasses, bushes, trees

• Many are from arid regions

• Native species are usually available

• Can be used for forage, biomass, habitat, landscaping, and dust control

Shrimp and halophytes

Irrigation of halophyte crops with shrimp farm effluents: Pro’s & cons

• Reduces negative environmental impacts

• New agronomic crops in areas with great need

• uses native plants

• restoration of mangroves

• Often disturbs natural environment

• May cause salinization of soil & groundwater

• Economics not proven

Shrimp and Seaweeds• Gracilaria and shrimp production

in Hawaii

Sustainable Aquaculture - Arizona Aquaculture Website

• Extension Information

• Links to other projects

Additional References & Websites• Samocha, Lawrence & Pooser 1998. Growth of P.

vannamei in low salinity. Israeli J. Aquaculture 50:55-59.

• Forsberg et al. 1996 &1997. Red drum in saline groundwater.

• Hopkins et al 1993. Shrimp pond nutrients.J. of WAS 24:304-320.

• http://ag.arizona.edu/azaqua http://www.desertsweetshrimp.com http://www.shrimp.ga.com http://www.sciam.com/1998/0898issue

Sustainable Aquaculture Predictions• Many irrigation systems will encourage

multiple use.

• Cages in reservoirs will be restricted to developing countries.

• Shrimp farming with in-land low salinity will grow.

• Shrimp in coastal areas will switch to integration with irrigated halophytes or seaweed/mangrove systems.

Dawn of Aquaculture/Irrigation