New Research: Shark Feeding May Not Affect Behavior

Shark-based tourism that uses bait to reliably attract shark so that divers can view them is a growing industry, but remains controversial. Some people argue it irretrievably changes shark behavior, but one study, recently published online at PLOS ONE, suggests the contrary. Here is a summary.

Over seven years, the study's two researchers tracked 48 bull sharks from a long-term shark feeding site at Fiji's Shark Reef Marine Reserve, and reefs along the Beqa Channel on the southern coast of Viti Levu. It became apparent that the sharks are not permanent residents of the marine reserve, but use the broader southern coast of Viti Levu as their stomping ground. While individual behavior varied, most are attracted to the feeding site if they're in the area, regardless of whether it's a feeding or non-feeding day, but they remain for more consecutive hours on feeding days. Some nearby individuals do not come to the feeding site, even if food is being offered.

Bull sharks can be considered typical "wild animals" that are generally human-averse. They tend to avoid the area when humans are present, and hence food provisioning is essential to elicit human-oriented behavior. The observed sharks use the area around the feeding site in the morning before spreading out over Shark Reef throughout the day, then dispersing over the entire area at night, perhaps foraging in the mouth of the Navua River mouth or even upriver at night. They intermittently leave the area for a few consecutive days throughout the year, and for weeks to months at the end of the calendar year before returning to the feeding site. It remains unknown where they exactly reproduce.

While bull sharks respond to the food when encountering it, the feeding operation does not appear to drive their long-term movements. The sharks are not strongly conditioned, otherwise they would be expected to be at almost every feed. Evidence is accumulating that chumming and food provisioning are unlikely to fundamentally change movement patterns over time through large areas, and seem to only have a minor impact on the behavior of large predatory sharks.

But despite the behavior and movement patterns found in this and previous studies being regarded as "normal," it is possible that the hand-feeding of sharks at Shark Reef for more than a decade has been attracting bull sharks to the area, and that individual sharks visit Shark Reef more often and/or spend more time in the area. This may raise concerns about increased susceptibility to local fishing. However, the feeding operation researchers looked at is closely linked to a local marine conservation project which protects all sharks in the marine reserve and adjacent coastal areas. The Shark Reef Marine Reserve is another example of how sharkfeeding tourism can be an effective strategy that can contribute to apex predator conservation, this time for bull sharks.

"Opportunistic Visitors: Long-Term Behavioural Response of Bull Sharks to Food Provisioning in Fiji," by JM Brunnschweiler and A. Barnett; published March 2013 in PLoS ONE 8(3): e58522. doi:10.1371/journal.pone.0058522