Feeding Flipper: a case study of a humandolphin interaction

Abstract

We document a human-dolphin interaction involving the illegal feeding of wild Bottlenose Dolphins (Tursiops sp.) in Cockburn Sound, Western Australia from 1993-2003. In 1993 only one dolphin was considered conditioned to human interaction through food reinforcement. By 2001, 16% (n = 12) of the resident community of 74 adult dolphins were conditioned, and at least 14 dolphins were conditioned by 2003. Of the 13 conditioned dolphins of known sex, 11 (85%) were males. We observed conditioned dolphins initiating interactions by approaching recreational fishing boats and by residing for several hours at boat ramps and shore-based fishing sites. We only observed recreational fishers feeding dolphins, although anecdotal reports indicated additional feeding sources. We used belt transects to determine the densities of recreational boats and encounter rates for conditioned dolphins across habitats within Cockburn Sound. Encounter rates and boat densities were positively correlated, suggesting an association between recreational boat density and the ranging patterns of conditioned dolphins. This study demonstrates how illegal feeding interactions can intensify over time to affect a potentially biologically significant proportion of a local dolphin population. This emphasizes the need for early and pro-active intervention and demonstrates the value of longitudinal, individual-specific wildlife studies.

Short Note: Depredation of a Sport Fishing Tournament by Rough-Toothed Dolphins (Steno bredanensis) off Angola

“…Second, the rough-toothed dolphins moved from boat to boat and followed close to the stern of boats for prolonged periods. Similar behaviour has been observed in conditioned (in this case, to deliberate feeding by humans) bottlenose dolphins in Australia, which moved methodically from boat to boat in expectation of food (Finn et al, 2008). Additionally, rough-toothed dolphins pursued the lures in toward the vessel sterns as the lines were retrieved.…”

“…For example, in Western Australia, the number of wild bottlenose dolphins conditioned to illegal feeding by recreational fishing boats increased from one animal in 1993 to at least 14 by 2003 (Finn et al, 2008). The rapid increase in depredation behaviour by several killer and sperm whale populations worldwide is considered to be an example of cultural transmission (Whitehead et al, 2004), and fishermen have observed bottlenose dolphins teaching depredation behaviour to their calves in the Florida king mackerel troll fishery (Zollett & Read, 2006).…”

“…Gear that becomes lodged in the mouth, throat, or stomach can lead to internal injuries, infection, starvation, and potentially death (Gorzelany, 1998;Powell & Wells, 2011;Stolen et al, 2013). Some bottlenose dolphins interacting with (i.e., depredating or being fed by) recreational or commercial fisheries specifically select habitat where there are concentrations of boaters or anglers (Finn et al, 2008;Powell & Wells, 2011), thus, also increasing their exposure to accidental propeller strike. Additionally, in geographic areas where dolphin depredation is frequent, fishermen may take retribution.…”

Recent Advances in Whale-Watching Research: 2013–2014

“…Only a small number of studies have investigated the impact of provisioning (feeding) wild dolphins (Finn, Donaldson, & Calver, 2008;Powell & Wells, 2011;Samuels & Bejder, 2004), despite the prevalence of these interactions. In 1988, commercial dolphin feeding programs were initiated north of Savannah, Georgia and banned in 1993, as the activity was deemed to violate the US Marine Mammal Protection Act (MMPA).…”

An Overview of Increasing Incidents of Bottlenose Dolphin Harassment in the Gulf of Mexico and Possible Solutions

“…The take of marine mammals, including harassment and feeding, is illegal under the U.S. Marine Mammal Protection Act of 1972 (MMPA), and concern is growing over human-dolphin interactions concentrated in certain coastal areas in the Gulf of Mexico where injuries or fatalities to bottlenose dolphins, specifically, have been documented. These encounters, which bear great potential and risk for injury to the public and to individual dolphins and populations, may take the form of interaction with recreational or commercial fishing vessels and gear (Wells et al, 1998;Powell and Wells, 2011), direct interaction with humans through feeding or swim-with activities (Colborn, 1999;Samuels and Bejder, 2004;Danil et al, 2005;Cunningham-Smith et al, 2006;Finn et al, 2008;Perrtree et al, 2014), or encounters with vessels during whale or dolphin viewing activities (Wells and Scott, 1997;Nowacek et al, 2001;Constantine et al, 2004;Goodwin and Cotton, 2004;Lusseau, 2006;Timmel et al, 2008). Impacts to wild dolphins from these activities include conditioning and alteration of normal foraging and resting behaviors; disturbance and ultimate dispersal of populations from preferred habitat; injury from vessel strikes or directed harm, and reduced reproductive success, all of which can threaten survival.…”