The Impact of Swim with Dolphin Activities on Spinner Dolphins

Lessons from a Citizens Science Project

The information collected by the community volunteers in this Citizen Science Project shows that (click on the links to see the data generated by the community volunteers in the various bays):

  a) People only use the spinner dolphin resting areas when dolphins are there,

  b) The People were there to target the dolphins,

  c) The Dolphins were prevented from descending into rest by people approaching too close,

  d) The Dolphins were disturbed throughout the day,

  e) Calves only practiced their aerial behaviors when they were not disturbed by people,

  f)  The observations during the serendipitous Human Exclusion period suggested that the dolphins will   come back to their traditional resting areas and go back to their normal resting behavior patterns relatively   quickly.

 

Long-term data on occupancy rates suggest that Honokohau Bay is the only traditional spinner dolphin resting bay where the occupancy rate increased after swim-with tours began on the Kona coast.

Observations suggest that this was because the boat traffic in and out of the harbor discourages dolphin-oriented activities, especially by swimmers and kayakers.

 

In 2004, several State sponsored working groups concluded by recommending that human exclusion zones be established around the core resting areas in Kealakekua, Honaunau and Hookena bays, like NOAAs proposed Time Area Closure.  The proposal was embraced by all but one of the resident stakeholder groups using the swim-with-dolphin community.

 

The data from this monitoring effort also suggest that the current viewing distance set by NOAA Fisheries in Hawai'i be extended from 50 to 100 yards, at least in the Resting areas.

It is not known how lack of rest during the day impacts the dolphins’ ability to feed, avoid predators and protect their young at night, but it is likely to impact all these activities negatively.

See the links below for more information from the Citizen Science Study in the Spinner Dolphin Resting Bays.

The resulting Final Report, was submitted to:

National Marine Fisheries Service,

Pacific Island Regional Office in 2009.

 

Kealakekua Bay was the bay that had the most coverage. It was where the Citizen Science monitoring began and it is where a serendipitous natural experiment took place, where the bay was closed off from human use for 18 days, leaving the dolphins to themselves in their Core Resting Area.

As a result the observations in this bay showed us both how much the spinner dolphins were affected by certain human activities, but also how fast they could recover if the repeated disturbances ceased.

Honaunau1.jpeg

The observations in these additional bays corroborated many of the findings from Kealakekua Bay, not only showing how the spinner dolphin population along the Kona Coast was disturbed in many of their traditional resting areas, but that their reaction to this disturbance also was consistent. 

Honaunau1.jpeg
Honokohau Bay.jpeg

Image from Marinas. com

Comparing the occupancy rates in the various bays along the Kona Coast shows how the spinner dolphin population adjusted their movement patterns to get away from the consistent harassment in the other bays. It also indicates which human activities were most disturbing.