Natural Habitat Design for Zoo-Housed Elasmobranch and Teleost Fish Species Improves Behavioural Repertoire and Space Use in a Visitor Facing Exhibit.

Abstract

Simple SummaryStudies investigating whether a captive environment is meeting the needs of the species housed are relatively common among captive mammals. However, studies exploring fish behaviour in captive display enclosures are far less common in the scientific literature. Focusing on a small group of sharks, rays and smaller fish within a single display, our objectives were to; assess whether the behaviours of a select number of individual fishes within a single display are altered after the environment is enriched to enhance environmental complexity and visitor exposure is reduced, and also to increase our understanding of captive fish behaviour to improve capacity for evidence-based management decisions. In summary, increased environmental complexity and reduced visitor interaction showed correlations with increased expression of natural behaviours in all fish studied, including increased space use and decreased abnormal repetitive behaviours in some species. These results reflect a change toward more natural wild behavioural time budgets. Studying behaviour change in fish in different environmental conditions provides a good basis for evidence-based decision making.This study investigated the behaviour of two Elasmobranch species; Southern fiddler ray (Trygonorrhina dumerilii, n = 1) and Port Jackson shark (Heterodontus portusjacksoni, n = 4) and two teleost species; moonlighter (Tilodon sexfasciatus, n = 1) and banded morwong (Cheilodactylus spectabilis, n = 1) living within a single enclosure. For this study, two treatments were compared, the original enclosure design, and then after the enclosure had been renovated to more closely represent the species natural habitats, with a raised front viewing glass to prevent visitor interaction. Behaviours such as resting, swimming and abnormal behaviours such as surface and perimeter swimming (elasmobranchs only) were recorded as well as location within the enclosure, for 10 days pre and 10 days post renovation. The Port Jackson sharks significantly reduced the performance of abnormal behaviours after renovation, and significantly increased the time spent near the exhibit front. The Southern fiddler ray increased resting post renovation, while the teleost species also spent more time near the exhibit front. Although a small sample size was used, the results suggest that a more naturalistic environment with multiple micro-habitats and effective visitor barriers allows for a greater proportion of the day spent exhibiting natural behaviours, greater space use and reduced stereotypes.