What can you find in the AQUA LAB?
1. The aquatic lab at the Tom Ridge Environmental Center has five 400-gallon Mini Fish Farms that raise fish and plants for educational programs. These tanks demonstrate how a closed system called aquaponics can raise plants and fish together.
2. There are also three 110-gallon display tanks along the hall wall that have different themes: “Gone Fishing” includes native fish species that are fished for sport and commercially, “Uninvited Guests” contains invasive species such as zebra mussels, round gobies, and goldfish, and “Catch of the Day” will contain native fish that came from the Lake Erie Watershed. The fish displayed in these tanks vary throughout the year. Several species of turtles are housed in various tanks in the room and are used for education. The fish are fed a variety of foods. The sunfish and steelhead take to pellet food well and makes up the staple of their diets. The yellow perch, largemouth bass, and walleye are fed live foods such as minnows, banded killifish, and worms. A colony of feeder guppies are being developed to make the program self-sufficient.
Mini Fish Farm
The Mini Fish Farm is a growing system for fish (as well as other aquatic animals and plants), which uses unique biofiltration and clarification devices that make the reuse of water possible. The Mini Fish Farm contains 400 gallons of water in a 5-foot diameter polyethylene tank. The only inputs required for normal operation are 10 gallons of water and 1.5 kwh of electricity per day. The system was designed to operate with a minimum of technical knowledge. The system can grow a population of fish whose total weight is as high as 50 pounds when maintained properly. The water flows as follows: Water is siphoned from the bottom of the large tank into the clarifier then flows through the biological filter. When the water leaves the biological filter the water is either sent back to the main tank by airlift or to the plant tray by airlift. The water then flows through the plant tray back into the main tank.
Clarifier
The clarifier removes settleable wastes from the water and passes clarified water down through the biofilter chamber then returns to the tank by an airlift. The water returns free of the settleable solids and lower in dissolved nutrients. The clarifier is cleaned daily to remove the settled wastes. A filter pad is used to attract and remove the settled wastes before they pass into the biofilter.
Biological Filter
The biological filter provides the necessary surface area for the growth of nitrifying bacteria. These bacteria work most efficiently at temperatures above 55°F. Biofiltration is a natural, 2-step process that changes ammonia first to nitrites and then to harmless nitrates. This process is performed by two species of nitrifying bacteria, Nitrosomonas and Nitrobacter. These bacteria are found naturally in the soil, air, and water. They attach themselves to solid surfaces forming what feels like slime. The ceramic biomedia inside the biofilter provide a very large amount of surface area for the bacteria to colonize.
Water Changes
The aquaponics system is designed to operate with only 10 gallons per day of water exchange under ideal conditions. The reason water is changed is to reduce ammonia and nitrite, tank cleaning, water clarification, and general maintenance.
Aeration System
The design of these systems allows a very low energy air compressor ($0.06 per day) to provide the pumping, bilofilter, and aeration functions of the system. By using an air-lift from the external biofilter, water flow is established between these components. This flow is directed into the tank to provide a counter clockwise water rotation. The air diffusers are suspended from the side of the tank assist in water circulation, which “spins” heavier-than-water particles toward the center of the tank where they can be absorbed by the siphon assembly. Air from the compressor is also directed through a series of air diffusers, which break the air up into very small bubbles. As these bubbles rise through the water, oxygen from the air dissolves into the water, providing for the needs of the fish.
Plant Tray
The plant tray allows plants to grow without soil. Seeds are placed in rockwool propagation cubes, which are held in the tray by small plant baskets that suspends the plant so the roots are in the rockwool are in the water. The plants remove nutrients from the water. The lighting system is very powerful and promotes plant growth. The plant species vary throughout the year. The plants often used are: lettuce, spinach, kale, marigolds, winter wheat, and lavender. The water level remains the same due to a drain in the tray that returns the water back to the main tank.
Species Profiles
Bluegill
Bluegills are found in lakes, small farm ponds, and the slower parts of warmwater streams and rivers, habitats similar to the largemouth bass that have aquatic weeds. In the daytime, schools of small bluegills can be found close to shore. Larger bluegills prefer nearby deep water. Bluegills spawn from May, when the water temperature reaches 67 degrees, until August. The males fan small, saucer like depressions in sand and gravel as nests, and guard the eggs and hatched young. One female may deposit as many as 38,000 eggs in a nest. Bluegills eat aquatic insects, crustaceans, minnows, and aquatic plants and may grow to a foot long and up to two pounds.
Pumpkinseed
As highly colored as any tropical fish, the pumpkinseed is one of our most common and frequently caught sunfish. They are one of our smaller sunfishes, averaging eight inches in size. Pumpkinseeds are found in the quiet, weedy shallows of streams, lakes and ponds. They usually live in cooler water than other sunfish.
Pumpkinseeds spawn in late May to early June. The males clear small, saucer-shaped nests on the bottom in water three feet deep or less. Pumpkinseeds nest in small groups of up to three nests, but these groups of nests can be very close. Although the nest is guarded, other males may rush in and fertilize eggs. They feed heavily on snails and have special throat structures for doing so. Pumpkinseeds feed mostly on the bottom of a stream or pond, where they also eat burrowing and other aquatic insects.
Steelhead
Steelheads are a popular game fish in Lake Erie. A member of the Salmonidae family they are actually Rainbow Trout. Rainbow trout living in the ocean or large lakes, such as Lake Erie, lose some of their rainbow coloring and become silvery and are called “steelheads”. Members of the trout and salmon family are cold-water fish. The optimum temperature for steelhead is 55 degrees F. and they stay in water close to this temperature. Steelheads are caught in the fall when they begin to school off the mouths of creeks and are found just off shore. During the summer, anglers have to troll the deep off shore waters. Anglers enjoy fishing for steelhead because they are aggressive fighters. Though not as good table fare as walleye or perch, steelhead, salmon and trout can be fine eating if properly prepared.
Largemouth Bass
The largemouth bass is Pennsylvania’s biggest sunfish. The state angling record is over 11 pounds, and the fish can grow two feet or more in length. It has a broad black stripe or a line of broken splotches running along its side from head to tail. The largemouth bass lives throughout Pennsylvania in suitable warm water habitat, which is usually a pond or small, weedy lakes.
In true sunfish style, the male largemouths fan a circular nest for spawning and aggressively defends the nest site, eggs and young. Largemouths spawn in spring and early summer, when water temperatures remain at 60 degrees for about three days. Young bass feed on zooplankton, insects and small fishes, and they are cannibalistic on one another. Adult largemouths are predators and eat fish and crayfish, frogs, snakes, and even small mammals and birds, like mice and ducklings that happen onto the water’s surface. Largemouth bass feed day and night.
Walleye
Walleyes are the biggest, toothiest member of the perch family in North America. Walleyes live in large lakes, big streams and rivers. Walleyes travel, feed and spawn in schools. Young walleyes feed on zooplankton. When they reach several inches long, they switch to other small fish as their primary food. Typically, adult walleyes feed at dusk during the cooler months and at night during the summer. The light-reflective coating behind the walleye’s retinas, which gives the eye the glowing appearance, is an adaptation to feeding at night and in dim light. Walleyes are often the top predator fish in their habitat, eating other fishes, frogs, crayfish and large insect larvae. Walleyes can grow to 36 inches. The state record is over 17 pounds.
Yellow Perch
Yellow perch live in warm or cool lakes, ponds and sluggish streams. A prime yellow perch lake is cool and clear, with a sandy or gravelly bottom and rooted underwater vegetation. Yellow perch spawn in spring, April and May, when water temperatures are in the mid-40s to mid-50s. Female perch can produce up to 100,000 eggs. The eggs are deposited in a long, sticky gelatinous mass that drapes over underwater objects. Young perch feed on zooplankton and small aquatic insects, and are food for larger predator fish. Small fish, including small perch, are mainstays of the adult perch’s diet along with aquatic insects and crustaceans. They are active all year long, including under the ice, making them a favorite with ice fishermen. Perch commonly grow to 12 inches and may reach 14 inches.
How the park uses the Aquatic Lab
These systems are used to educate the public about the fish in Lake Erie, how aquaculture/aquaponics is used, how plants grow, and water quality monitoring. Students learn about fish biology, water quality, plant growth, and plant structure by studying these systems and its components.
Future Plans
The room is constantly evolving to adapt to the student groups that visit. Pennsylvania Fish and Boat Commission fish identification posters will be hung along with some fishing gear. A touch tank will be added to put macro-invertebrates and other small aquatic life that the students can handle and take a closer look at under magnified viewers such as snails, mussels, clams, and crayfish. The species of fish will change throughout the year. The possibility of brook trout being added as one of the species is being evaluated and would start in the fall 2008 if deemed manageable. The bluegills have spawned and young hatched this spring unexpectedly and the possibility of raising bluegills will be evaluated. A teaching kit is being developed and a lesson plan that will meet the Pennsylvania Education Standards. Items in the kit are water quality meters (measurements include pH, temperature, conductivity, dissolved oxygen, total dissolved solids, and salinity), fish identification text book, microscope slides of fish scales and otoliths, fish skeleton, fish mounts, and aquatic plant manuals.
Partners
The following organizations and associations contribute to the Aquatic Lab:
3-C-U Trout Association
Pennsylvania Department of Conservation and Natural Resources
Pennsylvania Department of Environmental Protection
Pennsylvania Fish and Boat Commission
Pennsylvania Sea Grant
Regional Science Consortium
S.O.N.S of Lake Erie