Comparing length-measurement methods and estimating growth parameters of free-swimming whale sharks (Rhincodon typus) near the South Ari Atoll, Maldives

2018 ◽  
Vol 69 (10) ◽  
pp. 1487 ◽  
Author(s):  
Cameron T. Perry ◽  
Joana Figueiredo ◽  
Jeremy J. Vaudo ◽  
James Hancock ◽  
Richard Rees ◽  
...  
Keyword(s):  
Growth Parameters ◽  
Measurement Methods ◽  
Nursery Ground ◽  
The South ◽  
Free Swimming ◽  
Invasive Approach ◽  
Rhincodon Typus ◽  
Non Invasive ◽  
Whale Sharks ◽  
Conservation Concern

Whale sharks (Rhincodon typus) are an endangered species whose growth and reproductive biology are poorly understood. Given their conservation concern, estimating growth parameters, as traditionally derived from vertebral samples of dead animals, is challenging. We used a non-invasive approach to investigate growth parameters of whale sharks frequenting the South Ari Atoll, Maldives, by analysing repeat measurements of free-swimming sharks over a 10-year period. Total lengths of the sharks were estimated by three measurement methods. Visual estimates underestimated the sizes of large sharks, whereas laser and tape measurements yielded results that were similar to one another. The Maldives aggregation consisted of primarily male (91%) juvenile (total length=3.16–8.00m) sharks and sharks new to the area were significantly smaller than were returning sharks, which suggests that this site may constitute a secondary nursery ground. Estimates of von Bertalanffy (VBG) growth parameters for combined sexes (L∞=19.6m, k=0.021year–1) were calculated from 186 encounters with 44 sharks. For males, VBG parameters (L∞=18.1m, k=0.023year–1) were calculated from 177 encounters with 40 sharks and correspond to a male age at maturity of ~25 years and longevity of ~130 years. Differences between these estimates and those from other studies underscore the need for regional studies.

scholarly journals Describing the population structure of Rhincodon typus occurring in the waters of Oslob– Cebu, Philippines– between March 2012 and June 2013, during the provisioning interaction hours.

2013 ◽  
Author(s):  
Gonzalo Araujo ◽  
Alessandro Ponzo ◽  
Daniel Geary ◽  
Samantha Craven ◽  
Sally J Snow ◽  
...  
Keyword(s):  
Population Structure ◽  
The Philippines ◽  
First Year ◽  
Systematic Data ◽  
Rhincodon Typus ◽  
Non Invasive ◽  
Monthly Average ◽  
Whale Sharks ◽  
The Impact ◽  
Systematic Data Collection

Background: Prior to this study, the aggregation of whale sharks in the waters of Oslob had never been described. Provisioning (Orams, 2002) activities started in late 2011, and systematic data collection in March 2012, attracting over 100,000 tourists in the first year, and is currently the most reliable aggregation of R. typus in the Philippines. Methods: Daily in-­‐water photographic identification was used as a non-­‐invasive means to describe the population throughout the study period. A total of 135 sharks were identified, and IDs were independently matched by three researchers to minimize error. Photogrammetry (Rohner, 2011) was adopted to complement population description. Results: Daily sightings ranged from 2 to 23 different animals in the interaction area (mean=11.14). A total of 109 males, 15 females and 11 R. typus of undetermined sex were described. The size was estimated for 73.3% of the population, with an average of 5.36m ±1.3m. Photogrammetry posed a mean of 5.63m ±0.59m on 14 sharks, 6.75% >than researchers’ estimates. Resighting (>1d) was observed in 66.7% of the population. Five individuals were present for >300d (n=443) in the interaction area, with a maximum of 420d. Nine individuals were successfully matched across regional hotspots including Donsol and Southern Leyte. Conclusion: Despite the presence of animals in Oslob year round and the influence of the provisioning, there appears to be a seasonal influx of animals, with a maximum of 46 different animals present in the month of June 2012 and again in May 2013, contrasting with a monthly average of 28.9. It appears these waters are important to the species and it’s paramount to fully investigate the impact of the provisioning on the population of R. typus in the Philippines.

scholarly journals Is Host Ectoparasite Load Related to Echeneid Fish Presence?

2008 ◽  
Vol 2008 ◽  
pp. 1-4 ◽  
Author(s):  
Gonzalo R. Mucientes ◽  
Nuno Queiroz ◽  
Simon J. Pierce ◽  
Ivan Sazima ◽  
Juerg M. Brunnschweiler
Keyword(s):  
Host Species ◽  
Field Data ◽  
Free Swimming ◽  
Rhincodon Typus ◽  
Isurus Oxyrinchus ◽  
Whale Sharks ◽  
Ectoparasite Load

This study used field data of echeneid and ectoparasite associations with free-swimming whale sharks (Rhincodon typus) and captured mako sharks (Isurus oxyrinchus) to test whether (1) echeneid presence was positively correlated with ectoparasite presence; and (2) the number of ectoparasites was negatively correlated with the number of echeneid fish. Data from whale and mako sharks do not support the first hypothesis whereas data from mako sharks yields support for the second hypothesis. The results indicate that echeneids do regulate the number of ectoparasites on at least some host species, but these benefits may be contingent on the echeneid species.

scholarly journals Describing the population structure of Rhincodon typus occurring in the waters of Oslob– Cebu, Philippines– between March 2012 and June 2013, during the provisioning interaction hours.

2013 ◽  
Author(s):  
Gonzalo Araujo ◽  
Alessandro Ponzo ◽  
Daniel Geary ◽  
Samantha Craven ◽  
Sally J Snow ◽  
...  
Keyword(s):  
Population Structure ◽  
The Philippines ◽  
First Year ◽  
Systematic Data ◽  
Rhincodon Typus ◽  
Non Invasive ◽  
Monthly Average ◽  
Whale Sharks ◽  
The Impact ◽  
Systematic Data Collection

Background: Prior to this study, the aggregation of whale sharks in the waters of Oslob had never been described. Provisioning (Orams, 2002) activities started in late 2011, and systematic data collection in March 2012, attracting over 100,000 tourists in the first year, and is currently the most reliable aggregation of R. typus in the Philippines. Methods: Daily in-­‐water photographic identification was used as a non-­‐invasive means to describe the population throughout the study period. A total of 135 sharks were identified, and IDs were independently matched by three researchers to minimize error. Photogrammetry (Rohner, 2011) was adopted to complement population description. Results: Daily sightings ranged from 2 to 23 different animals in the interaction area (mean=11.14). A total of 109 males, 15 females and 11 R. typus of undetermined sex were described. The size was estimated for 73.3% of the population, with an average of 5.36m ±1.3m. Photogrammetry posed a mean of 5.63m ±0.59m on 14 sharks, 6.75% >than researchers’ estimates. Resighting (>1d) was observed in 66.7% of the population. Five individuals were present for >300d (n=443) in the interaction area, with a maximum of 420d. Nine individuals were successfully matched across regional hotspots including Donsol and Southern Leyte. Conclusion: Despite the presence of animals in Oslob year round and the influence of the provisioning, there appears to be a seasonal influx of animals, with a maximum of 46 different animals present in the month of June 2012 and again in May 2013, contrasting with a monthly average of 28.9. It appears these waters are important to the species and it’s paramount to fully investigate the impact of the provisioning on the population of R. typus in the Philippines.

scholarly journals Salivary cortisol as a non-invasive approach to assess stress in dystocic dairy calves

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Levente Kovács ◽  
Fruzsina Luca Kézér ◽  
Szilárd Bodó ◽  
Ferenc Ruff ◽  
Rupert Palme ◽  
...  
Keyword(s):  
Birth Weight ◽  
Body Condition ◽  
Salivary Cortisol ◽  
Sampling Period ◽  
Dairy Calves ◽  
Birth Process ◽  
Invasive Approach ◽  
Non Invasive ◽  
Saliva Cortisol ◽  
Cortisol Levels

AbstractThe intensity and the magnitude of saliva cortisol responses were investigated during the first 48 h following birth in newborn dairy calves which underwent normal (eutocic, EUT, n = 88) and difficult (dystocic, DYS, n = 70) calvings. The effects of parity and body condition of the dam, the duration of parturition, the time spent licking the calf, the sex and birth weight of the calf were also analyzed. Neonatal salivary cortisol concentrations were influenced neither by factors related to the dam (parity, body condition) nor the calf (sex, birth weight). The duration of parturition and the time spent licking the calf also had no effect on salivary cortisol levels. Salivary cortisol concentrations increased rapidly after delivery in both groups to reach their peak levels at 45 and 60 min after delivery in EUT and DYS calves, respectively supporting that the birth process means considerable stress for calves and the immediate postnatal period also appears to be stressful for newborn calves. DYS calves exhibited higher salivary cortisol concentrations compared to EUT ones for 0 (P = 0.022), 15 (P = 0.016), 30 (P = 0.007), 45 (P = 0.003), 60 (P = 0.001) and 120 min (P = 0.001), and for 24 h (P = 0.040), respectively. Peak levels of salivary cortisol and the cortisol release into saliva calculated as AUC were higher in DYS than in EUT calves for the 48-h of the sampling period (P = 0.009 and P = 0.003, respectively). The greater magnitude of saliva cortisol levels in DYS calves compared to EUT ones suggest that difficult parturition means severe stress for bovine neonates and salivary cortisol could be an opportunity for non-invasive assessment of stress during the early neonatal period in cattle.

scholarly journals Regional movements of satellite‐tagged whale sharks Rhincodon typus in the Gulf of Aden

2021 ◽  
Author(s):  
Samantha Andrzejaczek ◽  
Michel Vély ◽  
Daniel Jouannet ◽  
David Rowat ◽  
Sabrina Fossette
Keyword(s):  
Gulf Of Aden ◽  
Rhincodon Typus ◽  
Whale Sharks

scholarly journals The Cat Mandible (II): Manipulation of the Jaw, with a New Prosthesis Proposal, to Avoid Iatrogenic Complications

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 683
Author(s):  
Matilde Lombardero ◽  
Mario López-Lombardero ◽  
Diana Alonso-Peñarando ◽  
María del Mar Yllera
Keyword(s):  
Imaging Techniques ◽  
Recovery Period ◽  
Prosthesis Design ◽  
Patient Specific ◽  
Mandibular Fractures ◽  
Rigid Fixation ◽  
Invasive Approach ◽  
Non Invasive ◽  
Iatrogenic Complications ◽  
Mandibular Body

The cat mandible is relatively small, and its manipulation implies the use of fixing methods and different repair techniques according to its small size to keep its biomechanical functionality intact. Attempts to fix dislocations of the temporomandibular joint should be primarily performed by non-invasive techniques (repositioning the bones and immobilisation), although when this is not possible, a surgical method should be used. Regarding mandibular fractures, these are usually concurrent with other traumatic injuries that, if serious, should be treated first. A non-invasive approach should also first be considered to fix mandibular fractures. When this is impractical, internal rigid fixation methods, such as osteosynthesis plates, should be used. However, it should be taken into account that in the cat mandible, dental roots and the mandibular canal structures occupy most of the volume of the mandibular body, a fact that makes it challenging to apply a plate with fixed screw positions without invading dental roots or neurovascular structures. Therefore, we propose a new prosthesis design that will provide acceptable rigid biomechanical stabilisation, but avoid dental root and neurovascular damage, when fixing simple mandibular body fractures. Future trends will include the use of better diagnostic imaging techniques, a patient-specific prosthesis design and the use of more biocompatible materials to minimise the patient’s recovery period and suffering.

scholarly journals Holistic description of new deep sea megafauna (Cephalopoda: Cirrata) using a minimally invasive approach

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Alexander Ziegler ◽  
Christina Sagorny
Keyword(s):  
Minimally Invasive ◽  
Dna Barcoding ◽  
Deep Sea ◽  
Imaging Techniques ◽  
Structural Complexity ◽  
Micro Computed Tomography ◽  
Invasive Approach ◽  
Non Invasive ◽  
Additional Support ◽  
Holistic Description

Abstract Background In zoology, species descriptions conventionally rely on invasive morphological techniques, frequently leading to damage of the specimens and thus only a partial understanding of their structural complexity. More recently, non-destructive imaging techniques have successfully been used to describe smaller fauna, but this approach has so far not been applied to identify or describe larger animal species. Here, we present a combination of entirely non-invasive as well as minimally invasive methods that permit taxonomic descriptions of large zoological specimens in a more comprehensive manner. Results Using the single available representative of an allegedly novel species of deep-sea cephalopod (Mollusca: Cephalopoda), digital photography, standardized external measurements, high-field magnetic resonance imaging, micro-computed tomography, and DNA barcoding were combined to gather all morphological and molecular characters relevant for a full species description. The results show that this specimen belongs to the cirrate octopod (Octopoda: Cirrata) genus Grimpoteuthis Robson, 1932. Based on the number of suckers, position of web nodules, cirrus length, presence of a radula, and various shell characters, the specimen is designated as the holotype of a new species of dumbo octopus, G. imperator sp. nov. The digital nature of the acquired data permits a seamless online deposition of raw as well as derived morphological and molecular datasets in publicly accessible repositories. Conclusions Using high-resolution, non-invasive imaging systems intended for the analysis of larger biological objects, all external as well as internal morphological character states relevant for the identification of a new megafaunal species were obtained. Potentially harmful effects on this unique deep-sea cephalopod specimen were avoided by scanning the fixed animal without admixture of a contrast agent. Additional support for the taxonomic placement of the new dumbo octopus species was obtained through DNA barcoding, further underlining the importance of combining morphological and molecular datasets for a holistic description of zoological specimens.

Platelet production estimation in thrombocytopenic patient: a non-invasive or invasive approach?

2004 ◽  
Vol 25 (4) ◽  
pp. 422 ◽  
Author(s):  
M. Todorovic-Tirnanic ◽  
V. Obradovic ◽  
N. Suvajdzic ◽  
I. Elezovic ◽  
M. Rolovic ◽  
...  
Keyword(s):  
Invasive Approach ◽  
Platelet Production ◽  
Non Invasive ◽  
Thrombocytopenic Patient

scholarly journals Diet of whale sharks Rhincodon typus inferred from stomach content and signature fatty acid analyses

2013 ◽  
Vol 493 ◽  
pp. 219-235 ◽  
Author(s):  
CA Rohner ◽  
LIE Couturier ◽  
AJ Richardson ◽  
SJ Pierce ◽  
CEM Prebble ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Stomach Content ◽  
Rhincodon Typus ◽  
Whale Sharks
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