Effects of Food Provisioning on the Daily Ration and Dive Site Use of Great Hammerhead Sharks, Sphyrna mokarran
Wildlife provisioning is popular, economically valuable, and a rapidly growing part of marine tourism, with great potential to benefit conservation. However, it remains controversial due to limited understanding of its implications on the behavior and ecology of target species. In this study, we mod...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2021-05-01
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| Series: | Frontiers in Marine Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fmars.2021.628469/full |
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| author | Vital Heim Vital Heim Félicie Dhellemmes Félicie Dhellemmes Félicie Dhellemmes Matthew J. Smukall Matthew J. Smukall Samuel H. Gruber Samuel H. Gruber Tristan L. Guttridge Tristan L. Guttridge |
| author_facet | Vital Heim Vital Heim Félicie Dhellemmes Félicie Dhellemmes Félicie Dhellemmes Matthew J. Smukall Matthew J. Smukall Samuel H. Gruber Samuel H. Gruber Tristan L. Guttridge Tristan L. Guttridge |
| author_sort | Vital Heim |
| collection | DOAJ |
| description | Wildlife provisioning is popular, economically valuable, and a rapidly growing part of marine tourism, with great potential to benefit conservation. However, it remains controversial due to limited understanding of its implications on the behavior and ecology of target species. In this study, we modeled how various abiotic and biotic factors influenced great hammerhead sharks’ (Sphyrna mokarran) use of a recreational dive site in Bimini, the Bahamas, where shark-feeding has been conducted since 2012. Further, we calculated bioenergetic models to estimate their daily ration and examined if individual sharks fulfilled their daily energetic requirements from food uptake during dives. Between December 2016 and May 2017, we collected data during 104 provisioning dives in collaboration with a local dive operator. Twenty-eight individual great hammerhead sharks were observed, 11 were philopatric (i.e., identified at the dive site in previous years), and 17 were new (i.e., identified at the dive site for the first time during this study) individuals. On average, four sharks were observed daily, occasionally up to nine individuals, with some individuals spending more than 2 h attending each dive, consuming up to 4.75 kg of provisioned food per dive and returning repeatedly throughout the study period. When we grouped sharks based on their previous experience of the dive site (i.e., philopatric vs. new sharks), we found significantly higher attendance indices, i.e., the number of attended dives divided by the total number dives, and longer presence times during dives in philopatric sharks and different responses toward the number of boats and conspecifics between the two groups. Overall, great hammerhead sharks increased their bait uptake during longer dives and when more boats were present at the dive site. Finally, nine of 12 provisioned great hammerhead sharks were regularly able to fuel their daily energetic requirements from provisioned food alone, with two sharks doing so on 77.8% of all dives. Our study provides insights into how large-bodied marine predators react toward wildlife tourism associated provisioning and allows further discussion about daily energy uptake during provisioning dives, its potential impacts on the ecological role of the target species and associated management measures. |
| first_indexed | 2024-12-14T19:10:09Z |
| format | Article |
| id | doaj.art-7d806eada2994535a0612fc4fd1798aa |
| institution | Directory Open Access Journal |
| issn | 2296-7745 |
| language | English |
| last_indexed | 2024-12-14T19:10:09Z |
| publishDate | 2021-05-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Marine Science |
| spelling | doaj.art-7d806eada2994535a0612fc4fd1798aa2022-12-21T22:50:44ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452021-05-01810.3389/fmars.2021.628469628469Effects of Food Provisioning on the Daily Ration and Dive Site Use of Great Hammerhead Sharks, Sphyrna mokarranVital Heim0Vital Heim1Félicie Dhellemmes2Félicie Dhellemmes3Félicie Dhellemmes4Matthew J. Smukall5Matthew J. Smukall6Samuel H. Gruber7Samuel H. Gruber8Tristan L. Guttridge9Tristan L. Guttridge10Department of Environmental Sciences, Zoological Institute, University of Basel, Basel, SwitzerlandBimini Biological Field Station Foundation, South Bimini, BahamasBimini Biological Field Station Foundation, South Bimini, BahamasFaculty of Life Sciences, Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Humboldt-Universität zu Berlin, Berlin, GermanyLeibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, GermanyBimini Biological Field Station Foundation, South Bimini, BahamasCollege of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK, United StatesBimini Biological Field Station Foundation, South Bimini, BahamasRosenstiel School of Marine and Atmospheric Sciences, University of Miami, Miami, FL, United StatesBimini Biological Field Station Foundation, South Bimini, BahamasSaving the Blue, Cooper City, FL, United StatesWildlife provisioning is popular, economically valuable, and a rapidly growing part of marine tourism, with great potential to benefit conservation. However, it remains controversial due to limited understanding of its implications on the behavior and ecology of target species. In this study, we modeled how various abiotic and biotic factors influenced great hammerhead sharks’ (Sphyrna mokarran) use of a recreational dive site in Bimini, the Bahamas, where shark-feeding has been conducted since 2012. Further, we calculated bioenergetic models to estimate their daily ration and examined if individual sharks fulfilled their daily energetic requirements from food uptake during dives. Between December 2016 and May 2017, we collected data during 104 provisioning dives in collaboration with a local dive operator. Twenty-eight individual great hammerhead sharks were observed, 11 were philopatric (i.e., identified at the dive site in previous years), and 17 were new (i.e., identified at the dive site for the first time during this study) individuals. On average, four sharks were observed daily, occasionally up to nine individuals, with some individuals spending more than 2 h attending each dive, consuming up to 4.75 kg of provisioned food per dive and returning repeatedly throughout the study period. When we grouped sharks based on their previous experience of the dive site (i.e., philopatric vs. new sharks), we found significantly higher attendance indices, i.e., the number of attended dives divided by the total number dives, and longer presence times during dives in philopatric sharks and different responses toward the number of boats and conspecifics between the two groups. Overall, great hammerhead sharks increased their bait uptake during longer dives and when more boats were present at the dive site. Finally, nine of 12 provisioned great hammerhead sharks were regularly able to fuel their daily energetic requirements from provisioned food alone, with two sharks doing so on 77.8% of all dives. Our study provides insights into how large-bodied marine predators react toward wildlife tourism associated provisioning and allows further discussion about daily energy uptake during provisioning dives, its potential impacts on the ecological role of the target species and associated management measures.https://www.frontiersin.org/articles/10.3389/fmars.2021.628469/fullwildlife tourismshark divingbioenergeticsendangered specieselasmobranch |
| spellingShingle | Vital Heim Vital Heim Félicie Dhellemmes Félicie Dhellemmes Félicie Dhellemmes Matthew J. Smukall Matthew J. Smukall Samuel H. Gruber Samuel H. Gruber Tristan L. Guttridge Tristan L. Guttridge Effects of Food Provisioning on the Daily Ration and Dive Site Use of Great Hammerhead Sharks, Sphyrna mokarran Frontiers in Marine Science wildlife tourism shark diving bioenergetics endangered species elasmobranch |
| title | Effects of Food Provisioning on the Daily Ration and Dive Site Use of Great Hammerhead Sharks, Sphyrna mokarran |
| title_full | Effects of Food Provisioning on the Daily Ration and Dive Site Use of Great Hammerhead Sharks, Sphyrna mokarran |
| title_fullStr | Effects of Food Provisioning on the Daily Ration and Dive Site Use of Great Hammerhead Sharks, Sphyrna mokarran |
| title_full_unstemmed | Effects of Food Provisioning on the Daily Ration and Dive Site Use of Great Hammerhead Sharks, Sphyrna mokarran |
| title_short | Effects of Food Provisioning on the Daily Ration and Dive Site Use of Great Hammerhead Sharks, Sphyrna mokarran |
| title_sort | effects of food provisioning on the daily ration and dive site use of great hammerhead sharks sphyrna mokarran |
| topic | wildlife tourism shark diving bioenergetics endangered species elasmobranch |
| url | https://www.frontiersin.org/articles/10.3389/fmars.2021.628469/full |
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