Aquaculture

The Faculty of Agriculture features several rearing systems that provide a variety of research conditions to enhance research and study of various finfish and shellfish species. Several bio-systems offer recirculation conditions, while others offer flow-through or static conditions with either saline or non-saline water.

Some of these systems allow for egg incubation or growth of fish fry, while others are used to house shellfish larvae. In total, the facilities offer over 60,000 liters in water volume to researchers and students.

The Lab

Within the Aquaculture Centre, technicians oversee the growth and development of approximately 40 strains of marine microalgae that have been isolated from ecosystems around the world. Cultures are inoculated on a weekly basis and maintained in a programmable growth chamber. Transferred cultures are grown in 20L Carboys, 150L Kalwall tubes, or a 300L bioreactor.

The density of the cultures is determined visually through microscopic inspection using a hemocytometer, or automatically through a Coulter counter.

Freshly harvested algae is used to feed Faculty of Agriculture shellfish stocks. The facility also has the capability to separate algal cells from media to produce a paste that can be stored at -80C or freeze-dried to be used in research.

Growth chambers

The Algal Production Lab houses three programmable growth chambers that can be adjusted for temperature and light intensity. As well, they can be regimented to meet the individual needs of the various strains of marine microalgae grown at the Centre.

Algal production is initiated from one microalgae strain in a 50 mL flask, transferred to a 1 L flask, transferred again to a 20 L carboy and finally to a 150 L Kalwall tube. The total duration of time, from initial inoculation to harvest, is approximately one month.

Kalwall tubes are placed in front of fluorescent lights to maximize cell growth. Carbon dioxide is added as a buffer to maintain a specific pH. Compressed air is also piped in at the bottom to aid in cell movement.

Algal research

Current research involves investigating strains of microalgae that contain significant levels of omega-3 fatty acids, particularly those known as EPA and DHA. Lipid extraction is performed on site and amounts of specific fatty acids are determined by gas chromatography. Quality microalgae is added to dairy and sheep diets, and anticipated benefits through improved animal health and milk quality are monitored.

Freeze-dried microalgae is mixed in with the diet and fed to dairy cows housed at the Agricultural Campus’ Ruminant Animal Centre.

In our Teaching Lab, students learn by doing and have fun putting lecture theory into practice. This custom-designed workspace has all the necessary gear and scientific hardware to conduct challenging experiments on all kinds of shellfish and finfish.

In the weekly three-hour lab sessions for each class, students learn the fundamentals of being a scientist, including methodology, data analysis, and preparation of scientific reports.

Students may learn the following skills:

• osmometry
• microscopy
• dissecting
• water quality testing
• necropsies
• blood sampling
• determining algal cell densities
• micro and macroalgae identification

Water Supply and Treatment

• main pumping area, consisting of 10 5 hp 3-phase pumps (120 gallons per minute [GPM]), plus 2 1.5 hp 3-phase pumps (50 GPM)
• packed column degassers for removing excess nitrogen gas from supply water
• mechanical filtration (sandfilters and cartridge filters)
• biological filtration (2 cubic-meter trickling biofilters)
• UV sterilization

Temperature Control

• 2 parallel flow plate heat exchangers supplied with 13 psi saturated steam (~119 oC) to heat freshwater and seawater up to 24 oC
• 4 condensing units and 4 titanium chillers to bring freshwater and seawater down to 4 degrees C
• computer monitoring and control system
• Delta Controls DDC (Direct Digital Control) Computer Control and Monitoring System
• 24-hour automated alarm dial-out for critical alarms

Continuous monitoring for

• pump and compressor running status
• water supply flow rates
• air and oxygen supply pressures
• tank levels
• supply and system temperatures
• dissolved oxygen concentrations

Automated control of

• temperature
• photoperiod
• feeding

Emergency backup

In the event of a power failure, a backup diesel generator provides emergency power to keep all systems in operation without interruption.

Freshwater supply

• source: aquifer
• 100 gpm
• 9.5^oC constant

Seawater supply

• source: National Research Council-Institute for Marine Biosciences (NRC-IMB, Sandy Cove)
• 30 µm filtered seawater
• bi-weekly deliveries
• stored and circulated through two 60,000 L underground reinforced fiberglass storage tanks.
• use of 12,000L per week for algal production and recirculation system water replacement

Compressed air and oxygen

• two 5-hp air blowers deliver high-volume, low-pressure compressed air (135 cfm at 4 psi)
• two 3-hp air compressors deliver low-volume, high-pressure (120 psi) compressed air
• oxygen generator delivers 95% pure compressed O₂ at 40-50 psi

All rearing systems can be supplied with the following:

• ambient freshwater (9.5 ^oC)
• chilled freshwater (4.0 - 9.5 ^oC)
• heated freshwater (9.5 - 26 ^oC)
• chilled seawater (4.0 - 15 ^oC)
• heated seawater (15 - 26 ^oC)
• compressed air
• compressed oxygen