Drivers of Spatial Distributions of Basking Shark (Cetorhinus maximus) in the Southwest Pacific
Basking sharks (Cetorhinus maximus) were widely reported throughout New Zealand waters. Once commonly observed, and sometimes in large numbers, basking sharks are now infrequently reported. Basking shark observations are known to be highly variable across years, and their distribution and occurrence...
| Main Authors: | , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Frontiers Media S.A.
2021-04-01
|
| Series: | Frontiers in Marine Science |
| Subjects: | |
| Online Access: | https://www.frontiersin.org/articles/10.3389/fmars.2021.665337/full |
| _version_ | 1818647447426039808 |
|---|---|
| author | Brittany Finucci Clinton A. J. Duffy Tom Brough Malcolm P. Francis Marco Milardi Matthew H. Pinkerton Grady Petersen Fabrice Stephenson |
| author_facet | Brittany Finucci Clinton A. J. Duffy Tom Brough Malcolm P. Francis Marco Milardi Matthew H. Pinkerton Grady Petersen Fabrice Stephenson |
| author_sort | Brittany Finucci |
| collection | DOAJ |
| description | Basking sharks (Cetorhinus maximus) were widely reported throughout New Zealand waters. Once commonly observed, and sometimes in large numbers, basking sharks are now infrequently reported. Basking shark observations are known to be highly variable across years, and their distribution and occurrence have been shown to be influenced by environmental predictors such as thermal fronts, chl-a concentration, and the abundance of prey (zooplankton). Little is known of basking sharks in the South Pacific and more information on distribution, habitat use, and migratory patterns is required to better understand the species’ regional ecology. Here, we used bootstrapped Habitat Suitability Models [HSM, ensembled from Boosted Regression Tree (BRT) and Random Forest (RF) models] to determine the drivers of basking shark distribution, predict habitat suitability and estimated uncertainty in the South Pacific for the first time. High−resolution environmental (1 km2 grid resolution) and biotic data, including inferred prey species, and all available basking shark records across New Zealand’s Exclusive Economic Zone (EEZ) were included in the ensemble HSMs. The most influential driver of modeled basking shark distribution was vertical flux of particulate organic matter at the seabed, which may indicate higher levels of primary production in the surface ocean and higher prey density in the mesopelagic zone and at the seafloor. The BRT and RF models had good predictive power (AUC and TSS > 0.7) and both models performed similarly with low variability in the model fit metrics. Areas of high basking shark habitat suitability included the east and west coasts of the South Island, Puysegur Ridge, and Auckland Island slope. The outputs produced here could be incorporated into future management framework for assessing threat and conservation needs (e.g., spatially explicit risk assessment) for this regionally protected species, as well as providing guidance for future research efforts (e.g., areas of interest for sampling). |
| first_indexed | 2024-12-17T01:02:41Z |
| format | Article |
| id | doaj.art-ab0d69c95bb846099953ce22cfe8fbbb |
| institution | Directory Open Access Journal |
| issn | 2296-7745 |
| language | English |
| last_indexed | 2024-12-17T01:02:41Z |
| publishDate | 2021-04-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Marine Science |
| spelling | doaj.art-ab0d69c95bb846099953ce22cfe8fbbb2022-12-21T22:09:24ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452021-04-01810.3389/fmars.2021.665337665337Drivers of Spatial Distributions of Basking Shark (Cetorhinus maximus) in the Southwest PacificBrittany Finucci0Clinton A. J. Duffy1Tom Brough2Malcolm P. Francis3Marco Milardi4Matthew H. Pinkerton5Grady Petersen6Fabrice Stephenson7National Institute of Water and Atmospheric Research (NIWA), Wellington, New ZealandDepartment of Conservation, Auckland, New ZealandNational Institute of Water and Atmospheric Research (NIWA), Hamilton, New ZealandNational Institute of Water and Atmospheric Research (NIWA), Wellington, New ZealandFisheries New Zealand - Tini a Tangaroa, Ministry for Primary Industries - Manatū Ahu Matua, Wellington, New ZealandNational Institute of Water and Atmospheric Research (NIWA), Wellington, New ZealandNational Institute of Water and Atmospheric Research (NIWA), Hamilton, New ZealandNational Institute of Water and Atmospheric Research (NIWA), Hamilton, New ZealandBasking sharks (Cetorhinus maximus) were widely reported throughout New Zealand waters. Once commonly observed, and sometimes in large numbers, basking sharks are now infrequently reported. Basking shark observations are known to be highly variable across years, and their distribution and occurrence have been shown to be influenced by environmental predictors such as thermal fronts, chl-a concentration, and the abundance of prey (zooplankton). Little is known of basking sharks in the South Pacific and more information on distribution, habitat use, and migratory patterns is required to better understand the species’ regional ecology. Here, we used bootstrapped Habitat Suitability Models [HSM, ensembled from Boosted Regression Tree (BRT) and Random Forest (RF) models] to determine the drivers of basking shark distribution, predict habitat suitability and estimated uncertainty in the South Pacific for the first time. High−resolution environmental (1 km2 grid resolution) and biotic data, including inferred prey species, and all available basking shark records across New Zealand’s Exclusive Economic Zone (EEZ) were included in the ensemble HSMs. The most influential driver of modeled basking shark distribution was vertical flux of particulate organic matter at the seabed, which may indicate higher levels of primary production in the surface ocean and higher prey density in the mesopelagic zone and at the seafloor. The BRT and RF models had good predictive power (AUC and TSS > 0.7) and both models performed similarly with low variability in the model fit metrics. Areas of high basking shark habitat suitability included the east and west coasts of the South Island, Puysegur Ridge, and Auckland Island slope. The outputs produced here could be incorporated into future management framework for assessing threat and conservation needs (e.g., spatially explicit risk assessment) for this regionally protected species, as well as providing guidance for future research efforts (e.g., areas of interest for sampling).https://www.frontiersin.org/articles/10.3389/fmars.2021.665337/fullNew Zealandspecies distribution modelsboosted regression tree modelsthreatened specieselasmobranch |
| spellingShingle | Brittany Finucci Clinton A. J. Duffy Tom Brough Malcolm P. Francis Marco Milardi Matthew H. Pinkerton Grady Petersen Fabrice Stephenson Drivers of Spatial Distributions of Basking Shark (Cetorhinus maximus) in the Southwest Pacific Frontiers in Marine Science New Zealand species distribution models boosted regression tree models threatened species elasmobranch |
| title | Drivers of Spatial Distributions of Basking Shark (Cetorhinus maximus) in the Southwest Pacific |
| title_full | Drivers of Spatial Distributions of Basking Shark (Cetorhinus maximus) in the Southwest Pacific |
| title_fullStr | Drivers of Spatial Distributions of Basking Shark (Cetorhinus maximus) in the Southwest Pacific |
| title_full_unstemmed | Drivers of Spatial Distributions of Basking Shark (Cetorhinus maximus) in the Southwest Pacific |
| title_short | Drivers of Spatial Distributions of Basking Shark (Cetorhinus maximus) in the Southwest Pacific |
| title_sort | drivers of spatial distributions of basking shark cetorhinus maximus in the southwest pacific |
| topic | New Zealand species distribution models boosted regression tree models threatened species elasmobranch |
| url | https://www.frontiersin.org/articles/10.3389/fmars.2021.665337/full |
| work_keys_str_mv | AT brittanyfinucci driversofspatialdistributionsofbaskingsharkcetorhinusmaximusinthesouthwestpacific AT clintonajduffy driversofspatialdistributionsofbaskingsharkcetorhinusmaximusinthesouthwestpacific AT tombrough driversofspatialdistributionsofbaskingsharkcetorhinusmaximusinthesouthwestpacific AT malcolmpfrancis driversofspatialdistributionsofbaskingsharkcetorhinusmaximusinthesouthwestpacific AT marcomilardi driversofspatialdistributionsofbaskingsharkcetorhinusmaximusinthesouthwestpacific AT matthewhpinkerton driversofspatialdistributionsofbaskingsharkcetorhinusmaximusinthesouthwestpacific AT gradypetersen driversofspatialdistributionsofbaskingsharkcetorhinusmaximusinthesouthwestpacific AT fabricestephenson driversofspatialdistributionsofbaskingsharkcetorhinusmaximusinthesouthwestpacific |