scholarly journals Seasonal habitat use of whale sharks in the northern Gulf of Mexico, USA 2003 - 2013

2013 ◽  
Author(s):  
Jennifer A McKinney ◽  
Eric R Hoffmayer ◽  
Jim S Franks ◽  
Jill M Hendon ◽  
William B Driggers
Keyword(s):  
Home Range ◽  
Gulf Of Mexico ◽  
Habitat Use ◽  
Whale Shark ◽  
Shelf Edge ◽  
Northern Gulf Of Mexico ◽  
Use Patterns ◽  
Core Habitat ◽  
Whale Sharks ◽  
Satellite Tagging

Background: Reports of whale sharks (Rhincodon typus) in the northern Gulf of Mexico (GOM) date back to the 1930s. In 2003, the Northern Gulf of Mexico Whale Shark Research Program was established and began making directed efforts to document the regional occurrence, seasonal distribution and habitat preferences of whale sharks. Methods: Whale shark sightings data (WSS: 1989 – present; n=644) and tagging geoposition data (TD: 2009-2012; n=450) were used in seasonal kernel density (KD) analyses to delineate home range (95%) and core habitat (50%) use areas in the northern GOM. Kernel density estimation of distribution is a statistically robust manner of handling data sources with differing sampling designs (anecdotal vs. directed). Habitat use patterns from the two datasets were used to identify critical use areas. Results: In the study area, whale shark home range was 276,000 km2 (WSS) to 369,000 km2 (TD) in size, with 52,000 km2 (WSS) to 62,000 km2 (TD) being core habitat. Whale shark habitat use varied seasonally, with the largest home range occurring during summer (WSS: 213,000 km2) and fall (TD: 221,000 km2). Tag data revealed more winter habitat (75,000 km2) than the sightings dataset (41,000 km2), which was shifted further offshore to slope waters. Significant use patterns occurred along the continental shelf-edge, encompassing shelf-edge banks south of Louisiana, and near the mouth of the Mississippi River. Conclusions: The combination of sightings data and satellite tagging data represents an effective methodology for assessing seasonality of occurrence, distribution, and habitat use of whale sharks. Shelf-edge bank habitats were most commonly used by whale sharks in the region. Satellite tagging data provided additional evidence of connectivity between multiple jurisdictions, which lends support for international management of the species.

scholarly journals Seasonal habitat use of whale sharks in the northern Gulf of Mexico, USA 2003 - 2013

2013 ◽  
Author(s):  
Jennifer A McKinney ◽  
Eric R Hoffmayer ◽  
Jim S Franks ◽  
Jill M Hendon ◽  
William B Driggers
Keyword(s):  
Home Range ◽  
Gulf Of Mexico ◽  
Habitat Use ◽  
Whale Shark ◽  
Shelf Edge ◽  
Northern Gulf Of Mexico ◽  
Use Patterns ◽  
Core Habitat ◽  
Whale Sharks ◽  
Satellite Tagging

Background: Reports of whale sharks (Rhincodon typus) in the northern Gulf of Mexico (GOM) date back to the 1930s. In 2003, the Northern Gulf of Mexico Whale Shark Research Program was established and began making directed efforts to document the regional occurrence, seasonal distribution and habitat preferences of whale sharks. Methods: Whale shark sightings data (WSS: 1989 – present; n=644) and tagging geoposition data (TD: 2009-2012; n=450) were used in seasonal kernel density (KD) analyses to delineate home range (95%) and core habitat (50%) use areas in the northern GOM. Kernel density estimation of distribution is a statistically robust manner of handling data sources with differing sampling designs (anecdotal vs. directed). Habitat use patterns from the two datasets were used to identify critical use areas. Results: In the study area, whale shark home range was 276,000 km2 (WSS) to 369,000 km2 (TD) in size, with 52,000 km2 (WSS) to 62,000 km2 (TD) being core habitat. Whale shark habitat use varied seasonally, with the largest home range occurring during summer (WSS: 213,000 km2) and fall (TD: 221,000 km2). Tag data revealed more winter habitat (75,000 km2) than the sightings dataset (41,000 km2), which was shifted further offshore to slope waters. Significant use patterns occurred along the continental shelf-edge, encompassing shelf-edge banks south of Louisiana, and near the mouth of the Mississippi River. Conclusions: The combination of sightings data and satellite tagging data represents an effective methodology for assessing seasonality of occurrence, distribution, and habitat use of whale sharks. Shelf-edge bank habitats were most commonly used by whale sharks in the region. Satellite tagging data provided additional evidence of connectivity between multiple jurisdictions, which lends support for international management of the species.

scholarly journals Seasonal Occurrence, Horizontal Movements, and Habitat Use Patterns of Whale Sharks (Rhincodon typus) in the Gulf of Mexico

2021 ◽  
Vol 7 ◽  
Author(s):  
Eric R. Hoffmayer ◽  
Jennifer A. McKinney ◽  
James S. Franks ◽  
Jill M. Hendon ◽  
William B. Driggers ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Habitat Use ◽  
Continental Shelf ◽  
Site Fidelity ◽  
Seasonal Occurrence ◽  
Whale Shark ◽  
Shelf Edge ◽  
Rhincodon Typus ◽  
Aggregation Site ◽  
Whale Sharks

In the northern Gulf of Mexico (GOM), whale sharks (Rhincodon typus) form large aggregations at continental shelf-edge banks during summer; however, knowledge of movements once they leave aggregation sites is limited. Here we report on the seasonal occurrence of whale sharks in the northern GOM based on over 800 whale shark sightings from 1989 to 2016, as well as the movements of 42 whale sharks tagged with satellite-linked and popup satellite archival transmitting tags from 2008 to 2015. Sightings data were most numerous during summer and fall often with aggregations of individuals reported along the continental shelf break. Most sharks (66%) were tagged during this time at Ewing Bank, a known aggregation site off the coast of Louisiana. Whale shark track duration ranged from three to 366 days and all tagged individuals, which ranged from 4.5 to 12.0 m in total length, remained within the GOM. Sightings data revealed that whale sharks occurred primarily in continental shelf and shelf-edge waters (81%) whereas tag data revealed the sharks primarily inhabited continental slope and open ocean waters (91%) of the GOM. Much of their time spent in open ocean waters was associated with the edge of the Loop Current and associated mesoscale eddies. During cooler months, there was a net movement southward, corresponding with the time of reduced sighting reports. Several sharks migrated to the southwest GOM during fall and winter, suggesting this region could be important overwintering habitat and possibly represents another seasonal aggregation site. The three long-term tracked whale sharks exhibited interannual site fidelity, returning one year later to the vicinity where they were originally tagged. The increased habitat use of north central GOM waters by whale sharks as summer foraging grounds and potential interannual site fidelity to Ewing Bank demonstrate the importance of this region for this species.

scholarly journals Whale Shark Aggregations in the Northern Gulf of Mexico

2013 ◽  
Author(s):  
Eric Hoffmayer ◽  
Jennifer A McKinney ◽  
James S. Franks ◽  
Jill Hendon ◽  
William B Driggers III
Keyword(s):  
Gulf Of Mexico ◽  
Whale Shark ◽  
Shelf Edge ◽  
Potential Prey ◽  
Effective Technique ◽  
Specific Location ◽  
Northern Gulf Of Mexico ◽  
Whale Sharks ◽  
Directed Research ◽  
Juvenile Males

Background: The Northern Gulf of Mexico Whale Shark Research Program was initiated in 2003 to increase our knowledge of whale shark occurrence and distribution within the region. A primary goal was to obtain sightings data from “citizen scientists” to guide directed research. Whale sharks are typically solitary animals, but are known to aggregate in areas of high prey abundance. Methods: Whale shark sightings data reported from 2003 to present were compiled. Aggregations were defined as more than one whale shark, and large aggregations were defined as 10 or more sharks, observed at a specific location at the same time. Efforts were made to encounter aggregations to determine size and sex assemblage of the sharks, and to collect plankton samples to identify potential prey. Results: To date we have over 600 whale shark sightings reports and four research encounters of large aggregations. Whale shark aggregations represented 31% of reported sightings, 25% of which were large aggregations between 10-150 individuals. All of thereported large aggregations occurred during summer, almost exclusively along the continental shelf edge, with 41% occurring at Ewing Bank. Three out of the four scientific encounters occurred at Ewing Bank (2009, 2010, 2013). Aggregations were dominated by immature males that were primarily feeding on Euthynnus alletteratus eggs. Conclusions: The use of sightings data provided by “citizen scientists” has proven to bean inexpensive and effective technique for identifying whale shark aggregation locations in the northern Gulf of Mexico. Aggregation assemblages appear to consist of largely juvenile males that were feeding on tuna eggs. Similar to other regions, it is unknown if whale sharks in the northern Gulf of Mexico primarily consist of juveniles or if juveniles simply dominate these large feeding aggregations.

scholarly journals Whale Shark Aggregations in the Northern Gulf of Mexico

2013 ◽  
Author(s):  
Eric Hoffmayer ◽  
Jennifer A McKinney ◽  
James S. Franks ◽  
Jill Hendon ◽  
William B Driggers III
Keyword(s):  
Gulf Of Mexico ◽  
Whale Shark ◽  
Shelf Edge ◽  
Potential Prey ◽  
Effective Technique ◽  
Specific Location ◽  
Northern Gulf Of Mexico ◽  
Whale Sharks ◽  
Directed Research ◽  
Juvenile Males

Background: The Northern Gulf of Mexico Whale Shark Research Program was initiated in 2003 to increase our knowledge of whale shark occurrence and distribution within the region. A primary goal was to obtain sightings data from “citizen scientists” to guide directed research. Whale sharks are typically solitary animals, but are known to aggregate in areas of high prey abundance. Methods: Whale shark sightings data reported from 2003 to present were compiled. Aggregations were defined as more than one whale shark, and large aggregations were defined as 10 or more sharks, observed at a specific location at the same time. Efforts were made to encounter aggregations to determine size and sex assemblage of the sharks, and to collect plankton samples to identify potential prey. Results: To date we have over 600 whale shark sightings reports and four research encounters of large aggregations. Whale shark aggregations represented 31% of reported sightings, 25% of which were large aggregations between 10-150 individuals. All of thereported large aggregations occurred during summer, almost exclusively along the continental shelf edge, with 41% occurring at Ewing Bank. Three out of the four scientific encounters occurred at Ewing Bank (2009, 2010, 2013). Aggregations were dominated by immature males that were primarily feeding on Euthynnus alletteratus eggs. Conclusions: The use of sightings data provided by “citizen scientists” has proven to bean inexpensive and effective technique for identifying whale shark aggregation locations in the northern Gulf of Mexico. Aggregation assemblages appear to consist of largely juvenile males that were feeding on tuna eggs. Similar to other regions, it is unknown if whale sharks in the northern Gulf of Mexico primarily consist of juveniles or if juveniles simply dominate these large feeding aggregations.

scholarly journals Home range and habitat use of juvenile green turtles (Chelonia mydas) in the northern Gulf of Mexico

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
Margaret M. Lamont ◽  
Ikuko Fujisaki ◽  
Brail S. Stephens ◽  
Caitlin Hackett
Keyword(s):  
Home Range ◽  
Gulf Of Mexico ◽  
Habitat Use ◽  
Chelonia Mydas ◽  
Northern Gulf Of Mexico ◽  
Green Turtles

Environmental and individual effects on the behaviour and spawning movements of Lethrinus nebulosus on a coral reef

2017 ◽  
Vol 68 (8) ◽  
pp. 1422 ◽  
Author(s):  
R. C. Babcock ◽  
R. D. Pillans ◽  
W. A. Rochester
Keyword(s):  
Home Range ◽  
Habitat Use ◽  
Fork Length ◽  
Individual Variability ◽  
Long Distance ◽  
Individual Level ◽  
Use Patterns ◽  
Marine Park ◽  
Seasonal Factors ◽  
Lethrinus Nebulosus

Spatial management of fish populations can potentially be optimised by incorporating responses to environmental variables, such as diel, tidal, lunar and seasonal factors, but individual variability in habitat use and behaviour may complicate such efforts. Acoustic tagging and tracking of 84 Lethrinus nebulosus in the Ningaloo Marine Park indicated that sizes of individual habitat utilisation kernels were similar across diel and tidal cycles, but varied greatly among individuals. Clearly differentiated diel and tidal habitat use patterns were evident in significant proportions of individuals, particularly in relation to tidal phase. For the majority of residents, home-range sizes were reasonably stable over periods of 2–4 years, but in some cases core areas did shift over time. At seasonal time scales, peaks of seasonal activity and home range area were recorded during spawning season (October–December). Long-distance return migrations to spawning locations were observed that were among the longest observed for any reef fish (over 130km). Suspected spawning-related movements were recorded almost exclusively in fish >500-mm fork length, and were semilunar, following quarter moons in October–December. Significant individual-level variability in movement and habitat use patterns, evident across multiple temporal scales, has important implications for the management of L. nebulosus populations.

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