Supplemental Feeding for Ecotourism Reverses Diel Activity and Alters Movement Patterns and Spatial Distribution of the Southern Stingray, Dasyatis americana

Southern stingrays, Dasyatis americana, have been provided supplemental food in ecotourism operations at Stingray City Sandbar (SCS), Grand Cayman since 1986, with this site becoming one of the world’s most famous and heavily visited marine wildlife interaction venues. Given expansion of marine wildlife interactive tourism worldwide, there are questions about the effects of such activities on the focal species and their ecosystems. We used a combination of acoustic telemetry and tag-recapture efforts to test the hypothesis that human-sourced supplemental feeding has altered stingray activity patterns and habitat use at SCS relative to wild animals at control sites. Secondarily, we also qualitatively estimated the population size of stingrays supporting this major ecotourism venue. Tag-recapture data indicated that a population of at least 164 stingrays, over 80% female, utilized the small area at SCS for prolonged periods of time. Examination of comparative movements of mature female stingrays at SCS and control sites revealed strong differences between the two groups: The fed animals demonstrated a notable inversion of diel activity, being constantly active during the day with little movement at night compared to the nocturnally active wild stingrays; The fed stingrays utilized significantly (

Supplemental Feeding for Ecotourism Reverses Diel Activity and Alters Movement Patterns and Spatial Distribution of the Southern Stingray, \u3cem\u3eDasyatis americana\u3c/em\u3e

Southern stingrays, Dasyatis americana, have been provided supplemental food in ecotourism operations at Stingray City Sandbar (SCS), Grand Cayman since 1986, with this site becoming one of the world’s most famous and heavily visited marine wildlife interaction venues. Given expansion of marine wildlife interactive tourism worldwide, there are questions about the effects of such activities on the focal species and their ecosystems. We used a combination of acoustic telemetry and tag-recapture efforts to test the hypothesis that human-sourced supplemental feeding has altered stingray activity patterns and habitat use at SCS relative to wild animals at control sites. Secondarily, we also qualitatively estimated the population size of stingrays supporting this major ecotourism venue. Tag-recapture data indicated that a population of at least 164 stingrays, over 80% female, utilized the small area at SCS for prolonged periods of time. Examination of comparative movements of mature female stingrays at SCS and control sites revealed strong differences between the two groups: The fed animals demonstrated a notable inversion of diel activity, being constantly active during the day with little movement at night compared to the nocturnally active wild stingrays; The fed stingrays utilized significantly (

Undersea Constellations: The Global Biology of an Endangered Marine Megavertebrate Further Informed through Citizen Science

The whale shark is an ideal flagship species for citizen science projects because of its charismatic nature, its size, and the associated ecotourism ventures focusing on the species at numerous coastal aggregation sites. An online database of whale shark encounters, identifying individuals on the basis of their unique skin patterning, captured almost 30,000 whale shark encounter reports from 1992 to 2014, with more than 6000 individuals identified from 54 countries. During this time, the number of known whale shark aggregation sites (hotspots) increased from 13 to 20. Examination of photo-identification data at a global scale revealed a skewed sex-ratio bias toward males (overall, more than 66%) and high site fidelity among individuals, with limited movements of sharks between neighboring countries but no records confirming large, ocean basin-scale migrations. Citizen science has been vital in amassing large spatial and temporal data sets to elucidate key aspects of whale shark life history and demographics and will continue to provide substantial long-term value

Map of Grand Cayman Island showing study sites.

<p>Indicated are the locations of the supplemental feeding site Stingray City Sandbar (SCS), the two control sites South Sound and Rum Point, and a patch reef where female stingrays aggregated at night.</p

Comparative activity space sizes of fed and wild female stingrays.

<p>Activity space sizes, based on 95% kernel contours, of fed (open bars, n = 5) and wild (filled bars, n = 5) southern stingrays tracked manually at Grand Cayman during day, night and 24 hour periods. The thick horizontal lines inside the boxes represent the medians, the box edges show the upper and lower quartiles, and the whiskers represent minimum and maximum values.</p

Sex, size and detection duration of fed stingrays implanted with acoustic transmitters and monitored using two automated receivers deployed at Stingray City Sandbar (SCS), Grand Cayman.

<p>Sex, size and detection duration of fed stingrays implanted with acoustic transmitters and monitored using two automated receivers deployed at Stingray City Sandbar (SCS), Grand Cayman.</p

Comparative daytime vs. nighttime core areas (50% kernel contours) and activity spaces (95% kernel contours) of wild mature female stingray number 10 at the South Sound control site.

<p>Panel A) daytime; panel B) nighttime. The movement behavior displayed stingray number 10 is representative of the behavior of the four other wild females tracked at this site.</p

Diel detections of five mature female stingrays on bottom-fixed, automated acoustic receivers at Stingray City Sandbar (SCS).

<p>Percent values (y-axis) represent the number of days an individual stingray was detected on at least one receiver within the hourly time interval shown (x-axis). The values are expressed as a percent of the total monitored days (i.e., one or both receivers were present at SCS). Gray bars indicate typical times of ecotourism provided supplemental feeding.</p

Locations and approximate detection ranges of two bottom-fixed, acoustic receivers.

<p>The receivers were used for longer-term, automated tracking of five mature female fed southern stingrays at Stingray City Sandbar (SCS), Grand Cayman.</p

Comparative daytime vs. nighttime core areas (50% kernel contours) and activity spaces (95% kernel contours) of fed mature female stingray number 4 at Stingray City Sandbar (SCS).

<p>Panel A) daytime; panel B) nighttime. The movement behavior displayed by stingray number 4 is representative of the behavior of the four other fed females tracked at this site.</p