The J L Scott Aquarium and Living Displays, by Dr. Adrian Lawler

The J L Scott Aquarium and Living Displays

by Adrian Lawler, Ph.D.
(retired) Aquarium Supervisor (l984-l998) J. L. Scott Aquarium Biloxi, Ms 39530
Aquarticles

Originally published in 1995 as an updated Aquarium handout

The aquarium viewing area is composed of four alcoves which surround a large aquarium in the center. The theme of the aquariums illustrates the progression of water through the water cycle from freshwater to saltwater habitats. Water in the Gulf (represented by the main tank) evaporates and is carried inland in the form of clouds. Rainfall and associated runoff continue the cycle through a freshwater vivarium and the first alcove. The second alcove represents a salt marsh; the third represents lower salinity waters of the Mississippi Sound; and the fourth depicts higher salinity waters near the barrier islands and island passes. Each alcove contains four or five, 210-gallon aquariums with 1200-3600 gallon aquariums at the corners. The Gulf of Mexico tank contains sixteen, two-inch thick plexiglass windows, and sixteen airlifts. The tank is thirty feet in diameter, eight feet deep, and holds 42,000 gallons of salt water.

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The Aquarium has 46 display tanks and over 65 receiving, treatment, or holding tanks. Each tank is operated as a separate unit, i.e., water does not flow from tank to tank as in some aquariums. Since the Aquarium is located in a hurricane area, display aquariums and holding systems were designed so they could be operated on air from blowers powered by an emergency natural gas generator (with buried gas lines usually not disrupted during hurricanes). Air power is best managed through the use of airlifts and undergravel filters, which the majority of the Aquarium's tanks possess. Undergravel filters and associated airlifts provide aeration (via falling aerated water from the airlifts) and circulation down and through the substrate (crushed coral or gravel) and up and out of the airlifts. This circulation takes excretory products of display organisms and organics (from algal decay, excess food, and other similar compounds) to various bacteria that primarily reside on the substrate of the undergravel filter. These bacteria oxidize substances to less toxic compounds or decompose organic materials. The downward circulation of water through the undergravel filter collects suspended particles of organic debris in the substrate where bacteria decompose them. This process clarifies the water for viewing by the public. The Aquarium's display systems vary in size from 10 to 42,000 gallons.

Specimens for the aquariums are obtained primarily through three mechanisms: 1) collections by the Aquarium and other Gulf Coast Research Laboratory staff; 2) donations by fishermen, the public, local agencies (e.g., Mississippi State University Coastal Aquaculture Unit), local fish farms, or by various agencies who research or regulate certain species (e.g., alligators by the Department of Marine Resources); 3) and/or through purchases from biological supply houses or commercial collectors. The Aquarium does not purchase specimens from the public. Since the Aquarium primarily displays organisms from Mississippi and the adjacent Gulf of Mexico, it does not accept exotics unless they are being reared in aquaculture facilities in Mississippi. The Aquarium does not accept poisonous snakes or endangered species on State or Federal lists.

All incoming live specimens are visually checked for external injuries, parasites , and general health. After "holding" in receiving tanks for approximately two to seven days-thereby lessening stress from being captured-all healthy saltwater fishes are treated with various chemical solutions to eliminate parasitic dinoflagellates (one-celled plants), ciliates (one-celled animals), or external worms, i.e., those parasitic organisms that cause the most serious problems in closed tank systems. These types of external parasites can multiply rapidly in a confined space and parasitize the fish so heavily that death results. Large parasites-such as isopods (small flattened crustaceans), leeches, and copepods (small, usually cylindrical, crustaceans), which may be visible to the public and weaken the fish-are manually removed while the specimen is under sedation of MS-222 (a fish tranquilizer). Specimens with injuries which would require their removal from display due to extensive healing periods are returned to the environment. Freshwater fish are generally held from two to seven days to observe for the appearance of ich (a one-celled ciliate parasite). Saltwater invertebrates are generally given a freshwater dip (quick immersion and removal) or bath (immersion longer than a dip, usually five minutes or longer), or immersed in a fresh solution of saltwater prior to display. After treatments, specimens are introduced in appropriate aquarium areas for compatibility with the theme, salinity, specimens, and size.

The 46 display aquariums-to include the vivarium-are separate, closed systems primarily with undergravel filters powered by air from blowers and lighted with appropriate bulbs, some of which simulate natural sunlight. The aquariums receive light from 7:30 a.m. to 5 p.m. daily except Sunday. The aquariums are subjected to subdued light 14 !/2 hours per day. Since tanks are not identical with regard to species, sizes and numbers of specimens, illumination or feeding, each tank is maintained differently. The aquarium water temperature is ambient and varies from 70-78 degrees F. The water quality parameters of salinity, pH, ammonia, nitrite, and nitrate are analyzed periodically depending on the "biological load," which includes the mass of organisms, feeding rate, and algal/plant "die-off" rate in the tank. With the water flow via airlifts and supplemental pumps, there have been no oxygen problems and oxygen readings are not usually taken. Water changes and removal of organic debris through siphoning, draining, or mechanical filtration are conducted routinely. Currently, artificial sea salt, "Forty Fathoms," is dissolved in city water which has been filtered (through zeolites to remove ammonia and through activated carbon to remove chlorine and chloramine) and "aged" (held for several days prior to use and aerated). Artificial sea salt can be also mixed with city water which has been vigorously aerated to dissipate the chlorine and has had the ammonia negated by the addition of an ammonia remover. The resulting artificial sea water is used for the Aquarium's saline habitats. Natural, local saltwater is not employed for use in the aquariums because it may: 1) have a high sediment load which requires extensive filtration for water clarity, 2) change salinity rapidly which could stress the animals, 3) contain various toxins or dinoflagellate (one-celled plant) blooms which would require expensive filtration to clean, and/or 4) contain diseases and parasites which could affect the Aquarium's displays.

Visual observations are made daily of each tank prior to opening for the public. Injured animals or any animal showing signs of stress are removed to quarantine or holding aquariums for observation and possible treatment prior to being returned for display. The Aquarium Supervisor provides recommended treatment(s) for most fish diseases. A local veterinarian is on call to provide assistance with health problems as they relate to reptiles. The aquatic animal veterinarian of Marine Life Oceanarium in Gulfport, MS works cooperatively with the Laboratory on various projects. Most expired organisms are necropsied (dissected and examined) to ascertain the cause of death. Findings from such examinations enable the aquarium staff to better advise aquaculture ventures, pet stores, and the public concerning holding or culturing marine and aquatic organisms.

The Aquarium's living collections are fed natural foods such as: brine shrimp, insects, mealworms, earthworms, guppies, fish, squid, shrimp, crabs, freshwater plants, and various fruits on specific schedules. Artificial foods are also used routinely and are represented by: flake food, catfish pellets, trout chow, and turtle pellets. Cultures of brine shrimp, mealworms, earthworms, guppies, duckweed, Brazilian Elodea. and hornwort are maintained for feeding various organisms. After being collected, a number of the Aquarium's fishes are reared in display aquariums and are moved to larger display tanks as they mature. As it is generally harmful to move large fish, most of the fish in the main tank were introduced when small, and allowed to grow in the tank. Large fish, when moved, generally suffer skin, fin, and scale loss leading to infections, or ripping of membranes or mesenteries and associated blood vessels which support internal organs. This tearing of the mesenteries is due to the internal organs shifting positions in the body, or coelomic, cavity due to a change in gravity because the fish's body is no longer buoyed by the water. This tearing may lead to internal bleeding and possible death.

Supplemental mechanical (diatom and sand) and chemical (charcoal) filters are moved from aquarium to aquarium as needed to increase water clarity, decrease dissolved or suspended organics, and decrease algal, protozoan, or parasitic blooms. As previously mentioned, the Aquarium has a natural gas generator which supplies power to the blowers in times of electrical outages and hurricanes. This generator is the primary disaster equipment the Aquarium has needed to maintain its living collections since opening the building in 1984.