Shark-based tourism presents opportunities for facultative dietary shift in coral reef fish

Abstract

Tourism represents an important opportunity to provide sustainable funding for many ecosystems, including marine systems. Tourism that is reliant on aggregating predator species in a specific area using food provisioning raises questions about the long-term ecological impacts to the ecosystem at large? Here, using opportunistically collected video footage, we document that 61 different species of fish across 16 families are consuming tuna flesh at two separate shark dive tourism operations in the Republic of Fiji. Of these fish, we have resolved 55 to species level. Notably, 35 (63%) of the identified species we observed consuming tuna flesh were from ostensibly non-piscivorous fishes, including four Acanthuridae species, a group primarily recognized as browsers or grazers of algae and epibenthic detritus. Our results indicate that shark diving is having a direct impact on species other than sharks and that many species are facultatively expanding their trophic niches to accommodate the hyperabundance of resources provided by ecotourism.

Human‐induced shifts in habitat use and behaviour of a marine predator: the effects of bait provisioning in the blacktip reef shark

“…Further research is required to determine whether the results of the present study represent an isolated case and to what extend they apply to other localities for blacktip reef sharks and other taxa, as shark and ray provisioning is a popular activity throughout French Polynesia involving many species. In particular, it will be important to address provisioning management from an ecosystem perspective (Vignon et al, 2010;Drew & McKeon, 2019;Meyer et al, 2020) as non-targeted species can also be affected, potentially leading to cascading effects within the ecosystem.…”

“…An increasing number of studies over the last decade show that provisioning can have a number of impacts on individuals, including on their abundance and residency (Clua et al, 2010;Brunnschweiler et al, 2014;Kiszka et al, 2016), movement patterns and activity space (Fitzpatrick et al, 2011;Huveneers et al, 2013) or physiology (Barnett et al, 2016;Huveneers et al, 2018). In their review, Brena et al (2015) further highlighted that these most commonly described alterations of individual behaviour can have cascading effects at the group and community scales (Drew & McKeon, 2019;Meyer et al, 2020).…”

Reduced human activity in shallow reefs during the COVID-19 pandemic increases fish evenness

“…Other effects of recreational activities on fishes include reduced cleaning by cleaner ( Titus et al, 2015 ); shorter latency periods and escape distances ( Valerio et al, 2019 ); increased use of refuge during presence of divers and snorkelers ( Benevides et al, 2019 ). On the other hand, fish feeding based tourism has be shown to boost fish diversity ( Brunnschweiler and Earle, 2006 ; Feitosa et al, 2012 ) and to expand trophic niches ( Drew and McKeon, 2019 ). These human-induced changes may have cascading effects on other fish species ( Milazzo et al, 2006 ).…”

Facultative scavenging feeding habits in Acanthurus chirurgus (Bloch, 1787) (Acanthuriformes: Acanthuridae)

“…Facultative feeding habits have been reported in numerous groups of herbivorous fish. For example, Drew and McKeon (2019) observed many non-carnivorous fish species, including Acanthurus , eating small fragments of fish flesh (tuna heads) used to attract sharks during diving tourism activities in Fiji. Duarte and Acero (1988) found crustaceans, remains of soft corals, as well as fish scales and eggs, in the stomach contents of A.…”