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 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 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 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.

scholarly journals Population size estimates of pink river dolphins (Inia geoffrensis) using mark-recapture methods on photo-identification

2014 ◽  
Vol 9 (2) ◽  
pp. 132-139 ◽  
Author(s):  
Catalina Gómez-Salazar ◽  
Hal Whitehead ◽  
Fernando Trujillo
Keyword(s):  
Population Size ◽  
Conservation Status ◽  
Freshwater Ecosystems ◽  
Mark Recapture ◽  
Photo Identification ◽  
Population Size Estimate ◽  
Population Size Estimates ◽  
Inia Geoffrensis ◽  
Colombian Amazon ◽  
Size Estimates

Population size estimates of pink river dolphins (Inia geoffrensis) are critical to assess the conservation status of this species and the impacts of increasing human stressors in freshwater ecosystems. Photo-identifications of Inia dolphins were collected between February 2007 and August 2009 in two locations of the Colombian Amazon and Orinoco river basins. Population sizes of Inia were obtained by using the closed (Petersen) mark-recapture model on photo-identifications. The total population size estimate for right/left side individuals was 129/71 Inia dolphins (CV=0.36/0.35) in the Amazon location and 125/58 Inia dolphins (CV=0.77/0.69) in the Orinoco location. The survey and analysis protocols were designed to try to meet mark-recapture assumptions. However, photo-identification was incomplete in both study areas, and there could be recruitment and unequal probabilities of capture due to preferences of individuals for certain areas. Further effort should be focused towards expanding the photo-identification catalogues and creating long-term monitoring programs.

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 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.

First records of bats (Mammalia: Chiroptera) from Muong Phang cultural and historical site, Dien Bien province, Northwestern Vietnam

2017 ◽  
Vol 39 (3) ◽  
pp. 296-302
Author(s):  
Dao Nhan Loi ◽  
Vu Dinh Thong
Keyword(s):  
Conservation Status ◽  
Forest Area ◽  
Sound Recordings ◽  
The Public ◽  
The Family ◽  
Biological Taxa

The internationally renowned Muong Phang Cultural and Historical Site is located in the Dien Bien Phu region, northwestern Vietnam, and has received special attention from the public because of its great biodiversity. This site has a large forest area and other habitats including lakes, streams, rivers and paddyfield. These habitats would be ideal homes for bats and other biological taxa. However, in general, the wildlife of the Muong Phang Cultural and Historical Site receives little attention from scientists and authorities. Between 2014 and 2016, we conducted  series of surveys for bats in Muong Phang. Bat capture and sound recordings were the main procedure to obtain materials and data necessary for the assessment of diversity and conservation status. The results of the surveys this time revealed that there are 19 species of bats belonging to 7 genera, 5 families in the study area. Of these, a Myotis sp. is different from all the previously recorded Myotis bats from Vietnam, and, a Rhinolophus sp. is different from every described species of the family Rhinolophidae. This paper provides the first records of bats from Muong Phang with remarks on their taxonomy and conservation status.   Citation: Dao Nhan Loi, Vu Dinh Thong, 2017. First records of bats (Mammalia: Chiroptera) from Muong Phang cultural and historical site, Dien Bien province, Northwestern Vietnam. Tap chi Sinh hoc, 39(3): 296-302. DOI: 10.15625/0866-7160/v39n3.10641. *Corresponding author: [email protected]. Received 29 August 2017, accepted 10 September 2017 

scholarly journals Estimation of the Actual Incidence of Coronavirus Disease (COVID-19) in Emergent Hotspots: The Example of Hokkaido, Japan during February–March 2020

2021 ◽  
Vol 10 (11) ◽  
pp. 2392
Author(s):  
Andrei R. Akhmetzhanov ◽  
Kenji Mizumoto ◽  
Sung-Mok Jung ◽  
Natalie M. Linton ◽  
Ryosuke Omori ◽  
...  
Keyword(s):  
Cumulative Incidence ◽  
Surveillance System ◽  
Negative Binomial ◽  
Actual Number ◽  
Public Health Response ◽  
The Public ◽  
Health Response ◽  
Using Data ◽  
Insight Into ◽  
Actual Incidence

Following the first report of the coronavirus disease 2019 (COVID-19) in Sapporo city, Hokkaido Prefecture, Japan, on 14 February 2020, a surge of cases was observed in Hokkaido during February and March. As of 6 March, 90 cases were diagnosed in Hokkaido. Unfortunately, many infected persons may not have been recognized due to having mild or no symptoms during the initial months of the outbreak. We therefore aimed to predict the actual number of COVID-19 cases in (i) Hokkaido Prefecture and (ii) Sapporo city using data on cases diagnosed outside these areas. Two statistical frameworks involving a balance equation and an extrapolated linear regression model with a negative binomial link were used for deriving both estimates, respectively. The estimated cumulative incidence in Hokkaido as of 27 February was 2,297 cases (95% confidence interval (CI): 382–7091) based on data on travelers outbound from Hokkaido. The cumulative incidence in Sapporo city as of 28 February was estimated at 2233 cases (95% CI: 0–4893) based on the count of confirmed cases within Hokkaido. Both approaches resulted in similar estimates, indicating a higher incidence of infections in Hokkaido than were detected by the surveillance system. This quantification of the gap between detected and estimated cases helped to inform the public health response at the beginning of the pandemic and provided insight into the possible scope of undetected transmission for future assessments.

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