scholarly journals Whale shark regional research collaboration between Utila, Honduras and Isla Mujeres, México.

2013 ◽  
Author(s):  
Beatriz Eugenia Galvan ◽  
Steve Fox ◽  
Rafael de la Parra
Keyword(s):  
Research Collaboration ◽  
Western Hemisphere ◽  
Individual Identification ◽  
Whale Shark ◽  
Western Atlantic ◽  
Photo Identification ◽  
Large Numbers ◽  
Positive Individual ◽  
Whale Sharks ◽  
Bay Islands

Background. Utila, Bay Islands, Honduras, is one of the few locations in the Western Hemisphere where whale sharks can be spotted year-round, while off the northeastern Yucatan Peninsula, Mexico, they aggregate during summertime in large numbers of up to several hundred. When our research on these sharks began, we hypothesized they migrate south to north from Honduras, then to Belize and finally to Mexico. Methods. From 2007-2013, we documented the presence of whale sharks in both locations using visual tags and photo-identification, to establish the connections between the sites. The international whale shark library ECOCEAN was an important tool for this research. Results. Our research collaboration began on 2007, we have registered and photographed 59 “encounters”, from these, 9 were “Belizeans” and 8 become new Honduran recruits. While 5 more remain as unassigned since positive individual identification has not been possible yet. From our database and ECOCEAN compare, we know that we share several individuals in between the two locations, and some even visit Belize. Conclusion. At least some individuals of the western Atlantic population travel between Honduras and Mexico, and some hang around Belize in between as well.We conclude that whale sharks wander in the Caribbean, the Gulf of México and the open Atlantic Ocean, and aggregate when food blooms are available.

scholarly journals Whale shark regional research collaboration between Utila, Honduras and Isla Mujeres, México.

2013 ◽  
Author(s):  
Beatriz Eugenia Galvan ◽  
Steve Fox ◽  
Rafael de la Parra
Keyword(s):  
Research Collaboration ◽  
Western Hemisphere ◽  
Individual Identification ◽  
Whale Shark ◽  
Western Atlantic ◽  
Photo Identification ◽  
Large Numbers ◽  
Positive Individual ◽  
Whale Sharks ◽  
Bay Islands

Background. Utila, Bay Islands, Honduras, is one of the few locations in the Western Hemisphere where whale sharks can be spotted year-round, while off the northeastern Yucatan Peninsula, Mexico, they aggregate during summertime in large numbers of up to several hundred. When our research on these sharks began, we hypothesized they migrate south to north from Honduras, then to Belize and finally to Mexico. Methods. From 2007-2013, we documented the presence of whale sharks in both locations using visual tags and photo-identification, to establish the connections between the sites. The international whale shark library ECOCEAN was an important tool for this research. Results. Our research collaboration began on 2007, we have registered and photographed 59 “encounters”, from these, 9 were “Belizeans” and 8 become new Honduran recruits. While 5 more remain as unassigned since positive individual identification has not been possible yet. From our database and ECOCEAN compare, we know that we share several individuals in between the two locations, and some even visit Belize. Conclusion. At least some individuals of the western Atlantic population travel between Honduras and Mexico, and some hang around Belize in between as well.We conclude that whale sharks wander in the Caribbean, the Gulf of México and the open Atlantic Ocean, and aggregate when food blooms are available.

scholarly journals Regional connectivity of whale sharks demonstrated using photo-identification – Western Atlantic, 1999 - 2013

2013 ◽  
Author(s):  
Jennifer McKinney ◽  
Eric R Hoffmayer ◽  
Jason Holmberg ◽  
Rachel Graham ◽  
Rafael de la Parra ◽  
...  
Keyword(s):  
Population Size ◽  
Transition Probabilities ◽  
Regional Cooperation ◽  
Individual Heterogeneity ◽  
Whale Shark ◽  
Western Atlantic ◽  
Entire Study ◽  
Photo Identification ◽  
Initial Identification ◽  
Whale Sharks

Background: Although whale sharks (Rhincodon typus) occur circum-globally, most studies focus on feeding aggregations in small regional areas. Photo identification is a proven tool in assessing population size and structure. While population estimates have been obtained for individual aggregation sites, there has been a lack of broader estimates despite known movement. The aim of this work is to demonstrate connectivity throughout the Gulf of Mexico (GOM) and Caribbean, and provide the first regional population estimate. Methods: Photographs submitted to the ECOCEAN Whale Shark Photo-ID Library Sightings were used to identify individual sharks using techniques described in Holmberg et al. (2009). Sightings data were used to assess the lagged identification rate (LIR) in order to investigate residency, regional mixing, population size, and transition probabilities using modules within SOCPROG 2.4. Results: Identifications from 1998 – 2013, were obtained from Belize (n =132), Mexico (n=3642), Honduras (n = 360), and the USA (n=147). Fifty-four individual sharks were seen in more than one country and used for analysis. For the entire study area, LIR decreased rapidly between one and 64-127 (mean 94.4) days then slightly increased between 256-511 (mean 381.2) days, suggesting a near-annual resighting periodicity. Estimates of mean population size from the best-fitting model were 1897.39 ± 414.30 S.E. (95% C.I. 1191.77 – 2784.03). Evidence suggests individual heterogeneity in movement patterns. Resightings were most likely to occur in the country where initial identification occurred, with the exception of Belize. The highest site fidelity was in Mexico, followed by USA. Conclusions: This study demonstrated individual heterogeneity, fidelity to initial identification site and regional linkages. These data suggest that national and regional cooperation is required for successful whale shark management in the West Atlantic.

scholarly journals Regional connectivity of whale sharks demonstrated using photo-identification – Western Atlantic, 1999 - 2013

2013 ◽  
Author(s):  
Jennifer McKinney ◽  
Eric R Hoffmayer ◽  
Jason Holmberg ◽  
Rachel Graham ◽  
Rafael de la Parra ◽  
...  
Keyword(s):  
Population Size ◽  
Transition Probabilities ◽  
Regional Cooperation ◽  
Individual Heterogeneity ◽  
Whale Shark ◽  
Western Atlantic ◽  
Entire Study ◽  
Photo Identification ◽  
Initial Identification ◽  
Whale Sharks

Background: Although whale sharks (Rhincodon typus) occur circum-globally, most studies focus on feeding aggregations in small regional areas. Photo identification is a proven tool in assessing population size and structure. While population estimates have been obtained for individual aggregation sites, there has been a lack of broader estimates despite known movement. The aim of this work is to demonstrate connectivity throughout the Gulf of Mexico (GOM) and Caribbean, and provide the first regional population estimate. Methods: Photographs submitted to the ECOCEAN Whale Shark Photo-ID Library Sightings were used to identify individual sharks using techniques described in Holmberg et al. (2009). Sightings data were used to assess the lagged identification rate (LIR) in order to investigate residency, regional mixing, population size, and transition probabilities using modules within SOCPROG 2.4. Results: Identifications from 1998 – 2013, were obtained from Belize (n =132), Mexico (n=3642), Honduras (n = 360), and the USA (n=147). Fifty-four individual sharks were seen in more than one country and used for analysis. For the entire study area, LIR decreased rapidly between one and 64-127 (mean 94.4) days then slightly increased between 256-511 (mean 381.2) days, suggesting a near-annual resighting periodicity. Estimates of mean population size from the best-fitting model were 1897.39 ± 414.30 S.E. (95% C.I. 1191.77 – 2784.03). Evidence suggests individual heterogeneity in movement patterns. Resightings were most likely to occur in the country where initial identification occurred, with the exception of Belize. The highest site fidelity was in Mexico, followed by USA. Conclusions: This study demonstrated individual heterogeneity, fidelity to initial identification site and regional linkages. These data suggest that national and regional cooperation is required for successful whale shark management in the West Atlantic.

scholarly journals Sizing and scarring of whale shark (Rhincodon typus Smith, 1828) in the Cenderawasih Bay National Park

2021 ◽  
Vol 21 (3) ◽  
pp. 199-213
Author(s):  
Yusup A Jentewo ◽  
Roni Bawole ◽  
Tresia S Tururaja ◽  
Mudjirahayu Mudjirahayu ◽  
Zeth Parinding ◽  
...  
Keyword(s):  
National Park ◽  
The Body ◽  
Whale Shark ◽  
Gill Slit ◽  
Rhincodon Typus ◽  
Photo Identification ◽  
Dorsal Fin ◽  
Total Length ◽  
Whale Sharks ◽  
Photo Collection

This study aims to determine the total length and scar condition of the body of whale sharks (Rhincodon typus) in Cendrawasih Bay National Park (TNTC), Papua-Indonesia. Photo-identification was used to identify individuals of the whale shark R. typus based on spot patterns behind the last gill slit of each individual. Photo-identification was also used to determine the scar of the whale shark. The total length of whale sharks were estimated based on the length of a snorkeller (assumed to be 1.6 m) swimming alongside the whale shark. We identified 21 individuals of R. typus. Of these 21 individuals, 14 were new sightings and seven were re-sightings that have been recorded in the previous photo collection database. R. typus ranged in size from 2 to 5 m total length (average 3.78 m, ±0,86, N= 21). Based on their size, all individuals of whale shark were categorized as juvenile. 52% of R. typus identified had scars and 38 % were not and 10% were unknown. The majority of whale sharks had amputation (12 individuals) and abrasion (7 individuals) scars. Scars occurred most often on the caudal fin and dorsal fin, five and four individuals respectively. This information is useful for understanding potential threats and designing better management programmes for R. typus conservation in TNTC.

scholarly journals The ecological connectivity of whale shark aggregations in the Indian Ocean: a photo-identification approach

2016 ◽  
Vol 3 (11) ◽  
pp. 160455 ◽  
Author(s):  
Samantha Andrzejaczek ◽  
Jessica Meeuwig ◽  
David Rowat ◽  
Simon Pierce ◽  
Tim Davies ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Time Frame ◽  
Ocean Basin ◽  
Identification System ◽  
Whale Shark ◽  
Monte Carlo Simulation Study ◽  
Photo Identification ◽  
Christmas Island ◽  
Modelling Studies ◽  
Whale Sharks

Genetic and modelling studies suggest that seasonal aggregations of whale sharks ( Rhincodon typus ) at coastal sites in the tropics may be linked by migration. Here, we used photo-identification (photo-ID) data collected by both citizen scientists and researchers to assess the connectedness of five whale shark aggregation sites across the entire Indian Ocean at timescales of up to a decade. We used the semi-automated program I 3 S (Individual Interactive Identification System) to compare photographs of the unique natural marking patterns of individual whale sharks collected from aggregations at Mozambique, the Seychelles, the Maldives, Christmas Island (Australia) and Ningaloo Reef (Australia). From a total of 6519 photos, we found no evidence of connectivity of whale shark aggregations at ocean-basin scales within the time frame of the study and evidence for only limited connectivity at regional (hundreds to thousands of kilometres) scales. A male whale shark photographed in January 2010 at Mozambique was resighted eight months later in the Seychelles and was the only one of 1724 individuals in the database to be photographed at more than one site. On average, 35% of individuals were resighted at the same site in more than one year. A Monte Carlo simulation study showed that the power of this photo-ID approach to document patterns of emigration and immigration was strongly dependent on both the number of individuals identified in aggregations and the size of resident populations.

Seasonal occurrence, distribution and movements of the whale shark, Rhincodon typus, at Ningaloo Reef, Western Australia

1996 ◽  
Vol 47 (4) ◽  
pp. 637 ◽  
Author(s):  
JG Taylor
Keyword(s):  
Western Australia ◽  
Whale Shark ◽  
Gastropod Mollusc ◽  
Leeuwin Current ◽  
Mass Spawning ◽  
Ningaloo Reef ◽  
Turbid Waters ◽  
Large Numbers ◽  
Whale Sharks ◽  
North Western

Aerial surveys between 1989 and 1992 demonstrated that large numbers of whale sharks appear on Ningaloo Reef in north-western Australia during autumn, shortly after the coral has undergone mass spawning. This movement into the reef waters would allow whale sharks to capitalize on the increased production of zooplankton brought about as a result of this mass spawning of corals and other marine organisms. Sharks occupied mainly the relatively turbid waters on the reef front, where a northerly current prevailed, rather than the offshore, warmer waters of the southerly flowing Leeuwin Current. The sharks moved in to the reef front from offshore but, once inshore, the majority swam parallel to the reef. The maximum density in any sector of the reef at any one time was four sharks per km, recorded in May 1992. The longer the time since sharks first appeared on the reef, the greater was their tendency to aggregate in a particular region of the reef. Evidence is presented that indicates that whale shark numbers at the northern end of Ningaloo Reef declined during the latter half of the 1980s; this decline may be related to the massive destruction of coral by the gastropod mollusc Drupella cornus during this period.

Can citizen science monitor whale-shark aggregations? Investigating bias in mark–recapture modelling using identification photographs sourced from the public

2012 ◽  
Vol 39 (8) ◽  
pp. 696 ◽  
Author(s):  
Tim K. Davies ◽  
Guy Stevens ◽  
Mark G. Meekan ◽  
Juliane Struve ◽  
J. Marcus Rowcliffe
Keyword(s):  
Conservation Status ◽  
Accurate Estimation ◽  
Encounter Rate ◽  
Whale Shark ◽  
Mark Recapture ◽  
The Public ◽  
Photo Identification ◽  
Online Databases ◽  
Whale Sharks ◽  
Using Data

Context The conservation status of the whale shark, Rhincodon typus, remains uncertain. Throughout their range, whale sharks are a focus for wildlife tourism and many identification photographs taken by tourists have become available online, presenting a potentially valuable source of data for monitoring populations using mark–recapture techniques. However, the suitability of these photographs for mark–recapture models has yet to be investigated. Aims We explore the suitability of identification-photographs available from online databases to produce assessments of life-history parameters and conservation status of whale sharks in the Maldives. Methods To test the validity of using publically sourced images, we used photo-identification images collected from both experienced researchers and tourists between 2003 and 2008 to construct two databases. Images taken by tourists were compiled from online databases. Researcher and public databases were analysed separately and the results of mark–recapture models then compared. Key results The dataset constructed from online public databases did not violate the assumptions of mark–recapture modelling. Estimates of parameters and abundance obtained from models using these data were similar to those produced using data provided by experienced researchers. Conclusions Publically sourced data allowed for the accurate estimation of abundance of whale sharks. These estimates were not confounded by the suitability of photographs, probably because of the high encounter rate in the aggregation, the high residency rate of sharks and the retrospective nature of photo-identification, which limited heterogeneity in capture probability between marked and unmarked sharks. Implications Our findings support the use of publically sourced data for use in mark–recapture studies of whale sharks, at least in situations where sharks are resident to the location. This approach will be useful in regions where data collected by tourists are available online, and research funding is limited.

scholarly journals Long-term assessment of whale shark population demography and connectivity using photo-identification in the Western Atlantic Ocean

PLoS ONE ◽  
2017 ◽  
Vol 12 (8) ◽  
pp. e0180495 ◽  
Author(s):  
Jennifer A. McKinney ◽  
Eric R. Hoffmayer ◽  
Jason Holmberg ◽  
Rachel T. Graham ◽  
William B. Driggers ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Whale Shark ◽  
Population Demography ◽  
Western Atlantic ◽  
Photo Identification ◽  
Western Atlantic Ocean

scholarly journals Using an Electronic Monitoring System and Photo Identification to Understand Effects of Tourism Encounters on Whale Sharks in Ningaloo Marine Park

2019 ◽  
Vol 14 (3) ◽  
pp. 121-131 ◽  
Author(s):  
Emily Lester ◽  
Conrad Speed ◽  
Dani Rob ◽  
Peter Barnes ◽  
Kelly Waples ◽  
...  
Keyword(s):  
Electronic Monitoring ◽  
Preliminary Investigation ◽  
Whale Shark ◽  
Data Resource ◽  
Photo Identification ◽  
Marine Park ◽  
Whale Sharks ◽  
The Impact ◽  
Combined Data

In-water shark-based tourism is growing worldwide and whale sharks (Rhincodon typus) are one of the most popular targets of this industry. It is important to monitor tourism industries to minimize any potential impacts on target species. At Ningaloo, Western Australia, Electronic Monitoring Systems (EMS) have been installed on licensed tour vessels to collect information on encounters between snorkelers and whale sharks. This study combined data from the EMS with whale shark identification photographs, to assess the impact of in-water tourism on the encounter duration for individual sharks. During 2011 and 2012, 948 encounters with 229 individual sharks were recorded using EMS. Encounter durations between whale sharks and tourism vessels ranged between 1 and 59 min (mean = 11 min 42 s, SD = ±11 min 19 s). We found no evidence for a decline in encounter duration after repeated tourist encounters with individual sharks. Encounter duration varied among tourism operator vessels and were shorter when the sex of the whale shark could not be identified. Given that individual sharks were swum with on average 2.4 times per day (±SD 2.08), and up to 16 times over the course of the study, our results suggest that there is no evidence of long-term impacts of tourism on the whale sharks at Ningaloo. However, the inclusion of well-defined categories of whale shark behaviors and information regarding how interactions between tourists and whale sharks end will complement the data already collected by the EMS. This preliminary investigation demonstrates the potential for the EMS as a data resource to better understand and monitor the impacts of tourism interactions on whale sharks.

scholarly journals presence of whale sharks based on oceanographic variations in Cenderawasih Bay National Park, Papua, Indonesia

2021 ◽  
Vol 22 (11) ◽  
Author(s):  
JAFRY FERDINAN Manuhutu ◽  
DEWA GEDE RAKA WIADNYA ◽  
ABU BAKAR SAMBAH ◽  
ENDANG YULI HERAWATI
Keyword(s):  
National Park ◽  
Additive Model ◽  
Environmental Parameters ◽  
Analysis Data ◽  
Current Speed ◽  
Habitat Modeling ◽  
Sea Surface ◽  
Observation Data ◽  
Whale Shark ◽  
Whale Sharks

Abstract. Manuhutu JF, Wiadnya DGR, Sambah AB, Herawati EY. 2021. The presence of whale sharks based on oceanographic variations in Cenderawasih Bay National Park, Papua, Indonesia. Biodiversitas 22: 4948-4955. Oceanographic factors have an important role in the study of estimating the distribution of fish resource habitats. Sea Surface Temperature (SST), Sea Surface Chlorophyll (SSC), Current Speed, Sea Surface Height (SSH), and bathymetry are important parameters that have been used in estimating the habitat of certain species. Through analyzing these environmental factors, research on the appearance and distribution of whale shark habitats in the Cenderawasih Bay National Park in Papua, Indonesia, utilized field observation data and satellite imagery. This study applied data on the presence of whale sharks and oceanographic parameter data from satellite recordings during 2019 – 2020. Analysis of the relationship and habitat modeling between the monthly presence of whale sharks and environmental parameters was carried out through the Generalized Additive Model (GAM) statistical approach and spatial analysis through the Geographic Information System approach. In the GAM analysis, data on the presence of whale sharks was used as a response variable. In contrast, the predictor variables consisted of SST, SSC, current speed, SSH, and bathymetric data. The results showed that the highest frequency of whale shark presence occurred in the transitional monsoon, with an average presence of 31.77 ± 4.00 %. The study also showed that all predictors showed a highly significant relationship (P < 0.001) to the number of whale sharks present. SST values range from 30.3 – 31.3 °C, SSC of 0.39 – 0.86 mg/L, the current speed of 0.46 – 0.65 m/s, SSH showed 0.63 to 1.00 cm, and bathymetry between 40 – 50 m . In the GAM model, the SST and SSC parameters were the two most important parameters that affect the presence of whale sharks, followed by SSHD, depth (bathymetry), and current parameters.

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