Otter (Lutrinae) Care Manual - Association of Zoos and Aquariums

Association of Zoos and Aquariums 135
Otter (Lutrinae) Care Manual
After the planning and design team has done their due diligence and developed a plan, they are then
ready to issue a request for proposal (RFP).
We have included sections from an actual Request for Proposal (RFP) for the design of a life support
system for an Otter Exhibit (see Appendix R). Due to its length, it has been abridged but enough remains
to give you an idea of what is entailed. Other institutions have their own basic version of such a document
so they will have to modify the pro forma language to suit their requirements. A performance specification
for the exhibit has been included. The performance of a life support system is measured by its water
quality and water clarity. Those parameters can and should be quantified as they give the client a point of
reference with the contractor as to whether the design has met expectations.
This RFP does not address the issue of temperature control because this particular exhibit did not
require it. Otters in general seem to be tolerant of a wide range of temperatures depending on the species
(see Chapter 1.1). Nevertheless, each institution should determine as early as possible if water
temperature is a concern. If there is any doubt, it should be included in the performance specifications as
addressing it after the fact is usually very cost prohibitive.
Part 1: GLOSSARY OF RELEVANT TERMS
-Juan Sabalones, Instution S
Aquatic Life Support Systems: There are two types of aquatic life support systems--open and closed.
Open systems are only possible in certain locations. The primary advantage is (usually) lower cost for
construction and, potentially, ongoing operations. The primary disadvantage is less control over exhibit
water quality due to the inability to control the quality of the primary water source.
Open: An open or flow through system takes water from a source outside the exhibit such as a river, lake,
stream or even the ocean, and runs it through the exhibit at such a rate as to reduce the need for
filtration and then returns the water to that source. Such systems are not possible for all locations and are
far from ideal. The question of how much an open system costs verses a closed one, for example, is
difficult to answer. It depends upon how open the system is and what the water quality is adjacent to the
intake. If the otter exhibit is located where an open system is a viable option (i.e. all the proper
parameters can be met) then the primary considerations, especially in regards to salt water, involve a
need for some pretreatment (usually some form of sterilization and mechanical filtration). Depending on
the regulations in your local jurisdiction, there may be a need to treat the water prior to returning it to the
source. Zoos have long practiced a variation on this known as “dump and fill” where the water leaving the
exhibit goes straight to a drain.
Closed: A closed system, ideally, recycles the water so that water changes are performed only because
of evaporation and should keep all the required water quality parameters at appropriate levels. In reality,
even the best-designed and best-operated closed systems can only increase the amount of time between
water changes. Nevertheless, in many locations they may be the only option.
Closed systems are generally more expensive to build than an open counterpart. This would include
capabilities such as raw make-up (for salt water systems) and storage, proper mechanical, biological and
chemical filtration, denitrification, aeration, organics control, and backwash water recovery and especially,
a top-notch water quality laboratory.
Water Parameters: The United States Department of Agriculture has certain coliform counts that need to
be performed for exhibits that fall under the marine mammal category. Otters do not fall under that
category and therefore water tests are not required by any federal regulatory agency. Nevertheless, it is
prudent to perform at least weekly water quality tests for bacterial counts and daily tests of chemical
additive levels. Records should be maintained and available for inspection and reference if problems
arise.
Coliform bacteria: Coliform bacterial counts are used to monitor filtration system efficiency and keep track
of potentially harmful bacteria. Coliform counts should be done at least every other week and more often
if there are multiple animals using the pool (a policy regarding coliform testing should be set by the
institution). Often a MPN (Most Probable Number) per 100ml is given as an acceptable limit. However, a
more accurate measure is the total or fecal coliform count (NOAA 2006). There are no standards
established for fresh-water otter pools at this writing. At this time, it is suggested that coliform levels be
maintained at or lower than levels established for rescued pinnipeds by NOAA. These are: