June 22, 2024

The Harmful Effects of Inadvertently Conditioning a Wild Bottlenose Dolphin (Tursiops truncatus) to Interact with Fishing Vessels in the Indian River Lagoon, Florida, USA


Wendy Noke Durden


Abstract: Numerous accounts of social bottlenose dolphins (Tursiops truncatus) seeking human interactions have been documented. While there are several cases of dolphins seeking human interactions with no apparent benefit, dolphins may also be enticed to interact with humans through gradual habituation, usually involving a food source. Marine mammals frequently feed in association with commercial fisheries. Dolphins residing in the Indian River Lagoon (IRL), Florida, USA, may become conditioned to approaching commercial blue crab boats since the fishery regularly discards old bait fish at each trap. This routine may inadvertently acclimatize wild bottlenose dolphins to approach fishing vessels to feed on this supplemental food source. From 1998 to 2001, an adult bottlenose dolphin residing in the IRL estuary system regularly associated with commercial blue crab fishing boats. Focal observations revealed that the animal has become conditioned to approaching commercial crab boats (n = 110 min, n = 6 observations), spending all of its observed time feeding on discarded bait fish, following crab boats, or begging. The dolphin is readily resighted and well-known by fishers due to its tendency to closely approach and beg at fishing boats. The habituated dolphin is site-specific, with all observations and sightings (including fisher reports) occurring within a small 12.88 km area. This unintentional food provision and habituation of wild IRL dolphins to local fisheries may negatively impact the population. On 26 May 2001, this habituated dolphin approached a commercial vessel with a recreational fishing lure lodged in its mouth. Numerous reports from recreational fishers indicate that IRL dolphins also forage in association with recreational fisheries. Feeding and close interactions between wild dolphins and humans can lead to both animal and human injuries and fatalities. This paper documents the habituation of an IRL bottlenose dolphin to fishing vessels and reports the potentially harmful consequences of these interactions.


Document Type: Research article

DOI: 10.1578/AM.31.4.2005.413

Page Numbers: 413 – 419

Info SKU: Vol__31__Iss__4__Noke_Durden Category: