The behaviours and spatial distributions of captive sand tiger sharks (Carcharius taurus) in a marine aquarium

Nicholson, Cheryl Hebe Zoe

Abstract

This study was conducted between January 2003 and November 2004 to determine the effects of season (mating and non-mating), feeding regime and time period on voluntary swimming speeds, spatial distribution and behaviours of sand tiger sharks (Carcharias taurus) at the Blue Planet Aquarium, England. Each shark was observed for periods of 15 minutes and every 15 seconds the position of a focal shark and its behaviour were recorded. In total over 200 hours of observations were made.

In previous years, mating behaviours had been observed in this aquarium from January through to May (hereafter “the mating season”). Males increased swimming speed significantly and the females decreasing speed during the mating season. Spatial distribution in the tank was significantly different between mating - and non-mating seasons, with males spending more time in the areas commonly frequented by females during the mating season. The nearest neighbour and give-way occurrences, measures which may reflect the dominance hierarchy between sharks, were not influenced by mating season. C. taurus individuals who frequently gave-way at encounters were significantly more likely to avoid encounters at distance. During the mating season, pre-copulatory behaviours were also recorded. Numbers of displayed mating behaviours differed significantly between individuals. Furthermore, there was a significant positive correlation between swimming speeds and mating behaviours, male sharks with the fastest swimming speed displayed the most mating behaviours.

To determine feeding regime effects, data were recorded on both feeding and non-feeding days. Swimming speed was not found to significantly change between feeding and non-feeding days. Likewise, there was no effect on give-way occurrences between feeding and non-feeding days. Spatial distribution was however effected, and on feeding days the sharks spent more time in and around the sections where they were fed.

Time of day was divided in to six periods with varying lighting conditions and different diver and visitor presence/absence. Time period affected all variables recorded, and swimming speeds were significantly faster during the night time periods. Spatial distribution differed between the day and night time periods, and the sharks are particularly active at night (i.e. they spent a higher proportion of time patrolling and less time resting at night). Throughout the day time periods there were no detectable changes in shark swimming speed, spatial distribution and behaviours between, and the analysis suggests that presence of divers and visitors has no detectable effects on these sharks.

Citation

Nicholson, C. H. Z. (2009). The behaviours and spatial distributions of captive sand tiger sharks (Carcharius taurus) in a marine aquarium. (Thesis). University of Hull. Retrieved from https://hull-repository.worktribe.com/output/4215931

• Thesis Type: Thesis
• Deposit Date: Jul 28, 2014
• Publicly Available Date: Feb 23, 2023
• Keywords: Biological sciences
• Public URL: https://hull-repository.worktribe.com/output/4215931
• Additional Information: Department of Biological Sciences, The University of Hull
• Award Date: Aug 1, 2009