Special Issue Survey of Cetaceans in Captive Care

328 Couquiaudinteract with their environment. They add diversityand enrichment, as dolphins often are seen playingor chasing them. Such fish or crustaceans also are agood indicator of water quality. They help maintaina cleaner environment; however, they also have tobe monitored for diseases or parasites. Visitors aremore attracted to exhibits displaying cetaceans in amore natural setting, especially if visitors interactwith the animals in the water.Topography is an aspect of the pool design thathas been neglected in most artificial exhibits. Manypools present a very bare and sterile environment—flat bottom, straight wall, geometrical contourshape, painted concrete, and still water. Variationsin the topography and irregular shapes provide theanimals with opportunities for varying their swimpatterns. Irregularly shaped areas can prevent potentialstereotypic behaviours and help reduce stressby introducing variety. An irregularly shaped areahas less reverberation and, hence, provides a betteracoustic environment for cetaceans. No matter howlarge and varied a pool’s shape, it will never replacethe unlimited space of the ocean, especially forpelagic species. Even so, some elements can make itlook closer to inshore waters or coves.An island, a rocky edge with crashing waves,or a beach present interesting additions to thepool environment. Dolphins may favour deeperand larger areas of the pool for breeching and fastswimming; and shallow waters, confined space, orcoves for resting (Bassos & Wells, 1996).The following is a summary of features recurrentlysuggested by surveyed facilities for thedesign of pools and enclosures in regards totopography, shape, and environmental enrichment,as applied to both semi-natural and artificialenvironments (unless otherwise stated).• Avoid geometric contour shapes (e.g., circle,square, rectangle, even a “D” shape); preferirregular shapes. Circular pools tend to createvortex and encourage stereotypical swimming.Angles in square and rectangular shapes arewasted space and often create dead corners inwater circulation. An oval shape can be appropriatefor a medical pool. “D” shapes or kidneyshapes have been especially favoured for showpools and can be enhanced by incorporating anextra space with a shallow recess or an island.• Curves preferably should have a radius inscribedin obtuse angles (no less that 90º).• Provide at least one elongated area of great dimension,which allows for bursts in swim speed.• Design the pool bottom with varied depths andcontour shapes. This provides a better, lessreverberant acoustic environment and greatervariety in swim possibilities.• Incorporate underwater humps and hills, andbeaches and shallows; some species, such asthe bottlenose dolphin, like to rub themselves orstrand themselves occasionally in shallow waters.• Favour slanted walls over vertical and parallelwalls in concrete pools. It is even better toeliminate the delimitation between the wall andthe bottom (e.g., bowl shape) (see “Acoustics”section).• The pool bottom can be covered with sand toallow the dolphins to forage and play (with protectionover drains and sumps), providing theanimals have not shown tendencies to swallowsand (see “Construction and Materials” sectionfor restriction of use).• Add an artificial coral reef or rock work, boulders,and underwater landscaping (providedthey are not used as a target to redirect destructivebehaviour of the animals (Sweeney, 1990).Similar recommendations apply for the followingparagraph. Rocks should either be above orpartially above water or safely at more than 2m deep to avoid an animal mistakenly leapingon an unseen ledge. Their surface should besmooth to prevent skin abrasion and to facilitatecleaning.• Add live fish and crustaceans, sea grass, andso on, when the water system allows (venomousand spiked animals should be avoided) (seeChapter 6 for requirements).• Incorporate cascading water, sprinkler, hose,and bubble stream with a possibility of trainingthe animals to activate or turn off these featuresas part of the enrichment.• Incorporate a wave generator in concrete pools.A beach will be designed on the other end ofthe pool to absorb waves. The wave generatingmechanisms should be completely out of reachof the animals for safety reasons. Wave generatorsmight destabilise natural substrates such assand and stones in semi-natural enclosures.• Each pool preferably will be connected to atleast two other pools for easier animal managementor to provide refuge space for animals.Construction and MaterialsFacilities must be constructed of such materialsand maintained in good repair so as to ensure thatthe animals, the attending personnel, and visitorsare protected from injury and from the entranceof unwanted animals (Anonymous, 1979-1984,1995). Materials have to be durable, non-toxic,and easily cleaned and disinfected. Consumptionof pool components may occur as portions of thepool disintegrate or as the animals disassembleportions of their environment (e.g., peeling paint,crumbling artificial rocks, tiles, burst membranes,protruding pipes, etc.). For this reason, it is importantthat design efforts be directed not only toward