Collecting and Handling Aquarium Specimens
by Dr. Adrian Lawler
Extracted from the staff Operational Handbook which Dr. Lawler wrote as Aquarium
Supervisor for the J.L. Scott Marine Education Center and Aquarium, of Biloxi, MS
Aquarticles
There are numerous references in the literature on how to collect various organisms.
Special care should be taken with fishes because external damage to the slime coat, fins,
skin (and scale loss), head, and eyes can render a fish unusable for display, or if damage
is severe can lead to the death of the fish. Improperly handled large fish can die from
internal bleeding if they are not correctly supported to prevent tearing of mesenteries
(and associated blood vessels) when they are out of water. Organisms can also be injured
if frightened so they run into sides of a container (= concussion), or are overcrowded in
a container (e.g., catfish hitting other fish with their spines, collisions, and similar
causes of injury).
Collecting methods for fishes include: dip net, cast/brail net, hoop
net, seine, trawl, gill net, trap, and hook and line.
No matter what technique is employed, the best results (= less damage to fish) are
obtained when fish are out of the water the shortest periods of time possible. This means
that nets should be emptied into containers with water (from collection site) quickly,
gilled (and damaged) fish should be released, seines should be left in the water (not
dragged onto shore into dirt or sand) and the fish dipped out with a small net (or
dipper), and trawl times should be short (to decrease net damage) and net emptied into
water prior to sorting, Fish flopping on dirt, sand, nets, or rough substrates (and thus
abrading skin and fins) should be released. Damaged fish take time to heal (and sometimes
expensive medications) so it is generally not practical to keep them for possible display
(unless the fish is rare). Damage from rough collecting/handling is generally easi1y
visible one to two days after capture.
After collecting, organisms should:
- be transported in water from collection site.
- have proper aeration from a portable aerator or pump, agitation of water in
container, or water changes (of similar salinity).
- not be allowed to get too hot -e.g. transport container kept in shade, or
container with ice inside floated in transport water.
- not be over-crowded in transport container.
- discarded (or released) if dead or showing extreme signs of stress.
When the collected specimens are brought to the receiving area of the aquarium,
air lines should be dropped into all containers. Then the specimens can be acclimated
slowly to lower or higher temperatures and salinities by periodic addition of holding tank
water to the transport containers.
After acclimation the specimens are placed in the
"back-up-tanks" and observed for one to two days or more. If severe injuries are
observed, then those specimens are released or discarded. If the specimens look good
externally, then they are ready for treatment prior to going on display.
NOTE: Recently caught fishes generally will not eat, so
"back-up-tanks" should not be fed unless the specimens are being held in those
tanks for longer than about one week.
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