Science topic

Dolphins - Science topic

Mammals of the families Delphinidae (ocean dolphins), Iniidae, Lipotidae, Pontoporiidae, and Platanistidae (all river dolphins). Among the most well-known species are the bottle-nosed dolphin and the killer whale (a dolphin). The common name dolphin is applied to small cetaceans having a beaklike snout and a slender, streamlined body, whereas porpoises are small cetaceans with a blunt snout and rather stocky body. (From Walker's Mammals of the World, 5th ed, pp978-9)
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Hello, I run Kruskal-Wallis to test if there are statistical significant differences between the occurrence of dolphin sightings for two fishing season. There is not. I have to explain this graph, but I don't know how should be the correct caption.
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A couple of webpages that may help with the interpretation of box plots:
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Hi everyone, I would need a rule / method to estimate the number of dolphin individuals in a pod with the reference. Thanks to those who will be of help
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You're welcome! I'm afraid I don't have a reference for that though, it's just a tip I was given during an internship; but it's 4 because it's visually easier than dividing the group in anything smaller than that
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Dear all,
I am new to the world of Artemia and I am running into some troubles I hope someone might be able to help with :) I grow A. franciscana nauplii in the lab (starting salinity : 45g.l) in glass tanks, at 23 degrees C and feed them with dry spirulina (1g diluted in 200 ml of RO water, and then I dispense ~1-2 drops of this solution per individual). I use Red Sea Salt diluted in RO water but I do not proceeded at any water change between the moment they are naupli instar 1 and to the moment they form pairs. I incrementally increase the salinity by 5% every other day when the larvae are 10 days old to reach a salinity of 90g/l. I noticed from the literature that my Artemia are growing slowly: ~4weeks to reach adulthood. Not sure why, could be density, but this is not my biggest issue. See below...
When pairs form in the tanks, I isolate them into individual containers (so far, I have tried plastic cups, plastic drosophila vials, and glass beakers) in a volume of 150 ml of freshly made 90g/l salt water, give the pairs a drop of food. Within 48-72 hours, all of these isolated pairs die whereas those in the main tank, at the same salinity, with the same diet, exposed to the same photoperiod regime and the same air, are just fine. Does any one have any idea as to why the isolated pairs die when the others are fine?
Worth noting: in the isolated pairs, males develop very quickly some black spots on their legs are claspers. I do not know what this is, I can't really find any info on this potential (?) issue, but suggestions on what that might be are welcome :)
Many thanks in advance for your help and your time
Clementine
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Optimum salinity around 36 psu is reqd., but NH3 and DO level to be considered
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These pictures were taken in French Polynesia by a talented friend with whom I disagree on the species' identification.
I won't mention what I think it is, but I would gladly receive your opinions. He says the dark patches were enhanced by the photo.
Thank you very much in advance
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Rough-toothed it is.
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I have been told that with an average dorsal fin height measurement I can then estimate the space between tooth rakes. I am in the process of retrieving this piece of information from some colleagues, but I am then wondering how to calculate the actual space with only a mean DH measurement? Any suggestion? Many thanks
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Definitely. When you tell imageJ that that dorsal fin is XX cm high (in the set scale option), it will then calculate for itself that X pixels in that specific photograph = 1 cm.
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The bottlenose dolphin (Tursiops truncatus) in the Alboran Sea is known to feed on the catch retained in gillnets and also in small pelagic purse seines. At the same time an invasive alga, Rugulopteris okamurae, has recently appeared in Alboran, which is occupying the entire coastline and clogging the fishing gear. We do not know how the presence of the algae will affect the abundance and distribution of the dolphins, nor do we know whether the bottlenose dolphins left the waters of Alboran or suffered feeding problems as the fishing nets were less accessible.
Is there any other marine area where something similar is happening? Are there any areas where the appearance of invasive algae has negatively affected dolphin populations?
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I have personally not encountered anywhere any indication, much less evidence, of invasive macro-algae negatively affecting Tursiops or other delphinids. If fisheries are hampered I would rather hypothesize a potential positive effect for bottlenose dolphins, if this would lead to reduced fisheries removals of prey species. Dolphins predating on net-associated fish may well reflect too low abundance of free-ranging schools of prey fishes due to excessive human exploitation. Moreover, people should learn how to use this algae as a valuable resource, learn from the Japanese, since eradication is now surely impossible.
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I am building four seasonal habitat models for dolphins using sightings from boat surveys. For training presences (count) I have: dry season = 53, pre-monsoon = 10, monsoon = 48, and post-monsoon = 15 after removing multiple occurrences per grid cell.
To reduce sample selection bias, I am using the SWD ("samples with data") option in Maxent. This allows me to draw the environmental samples from a distribution of locations with the same selection bias as the occurrence data. I will draw environmental samples from randomly chosen boat track vessel points.
Given the number of dolphin sightings available for each season, what is the recommended sample size for background data (no sightings) to build a model for each of the four seasons using the SWD option? I am thinking of including at least one sample point per grid cell that the survey boat traveled through during each season. Thanks for sharing any suggestions.
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These papers may help you:
DOI: 10.1371/journal.pone.0240225
DOI: 10.1111/j.0906-7590.2006.04700.x
DOI: 10.1111/ecog.03149
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Hi segmentation experts,
I want to segment and measure the volume of the masseter muscles from CBCT data. I read Gupta et al. (2016) but am unsure how to do so in Dolphin. I read Pan et al. (2020) and can get some results from ITK-SNAP, however the segmentation is quite rough and if I make it smooth it may easily leak into adjacent muscles (see attached screenshot). Also, I do not have access to the AI algorithm used by Pan et al. (2020).
Your advice and help on ITK-SNAP is much appreciated. Thank you!
Best regards,
Andy
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I suggest you for segmentation in image they are a lot of methods , So you can use the automatic segmentation by method OTSU , that can find the optimal value based in histograms for do it the best segmentation.
I hope that be Claire for you and helpful. @ Andy Wai Kan Yeung
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Animal self-awareness usually be tested with the classical mirror test ( The mirror test is a measure of self-awareness developed by Gordon Gallup Jr in 1970, and animals which have passed the mirror test are common chimpanzees, bonobos, orangutans, dolphins, elephants, humans and possibly pigeons. ). However, the mirror test may not appropriate for test the self-awareness for invertebrates , especially arthropods, as visual signals usually be not crucial for these creatures, or they may not care about some marked points on their body etc. Is there any possible methods to test the self-awareness of these organisms?
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One thing you might consider is that, while passing the mirror test is fairly difficult, failing it is easy. You could first expose the animals to a mirror and see if any of them attempt to socialize, mate with, or attack the mirror. This would still assume that arthropods rely on visual cues, but if they do it would serve as a good first step. It would be unfortunate to design a more robust experiment around a mantis shrimp, for example, only to have it attack its reflection right away
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Recent studies show that sand mining is seriously affecting our environment, more than fossil fuel use. Some species are facing extinction as a result of sand mining on the ocean floor; the Yangtze River dolphin is already extinct. Traditionally, sand is used to manufacture glass. Today, huge skyscrapers erected in two years outnumber those constructed in the U.S. in a 20-year period due to accelerated rates of concrete-making in more populous and / or wealthier nations.
Sand, like coal and oil, is exhaustible, and a lot more plentiful.
In your opinion, is inevitable loss of all of the sand on Earth harmful?
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Sand mining destroys rivers and lakes on an unprecedented scale. This problem is particularly evident in Asia, where the construction boom places the highest demands on mineral resources. Not surprisingly, considering the use of cement in China in recent few years has exceeded total US consumption throughout the 20th century. It is also unlikely that sand from the deserts will be used in the near future, when we consider that even beautiful beaches in the Monterey area are being exploited for sand.
The basic consideration when choosing the source of sand is related to the optimum transportation theory, derived from the classic work of G. Monge published in 1781. The optimal solution always points to the area located near the building zones.
In order to best solve a more realistic optimization problem involving resources and anthropogenic climate change, we need to adapt construction technologies to local conditions that are very variable in different regions of the planet.
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If you think that because of their well researched communication (people try now to create a dolphin dictionary), their individual and emotional behaviour, their social skills and intelligence, their sense of self awareness, they (all kinds of whales and dolphins) are second most intelligent species on earth, ..-- so can we go on kill them?
How about international laws to forbid this?
Should You agree and want to support, so give a positive vote to:
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Sentience is the ability ability to perceive the world through neuroelectrical interpretation of one's surroundings as well as to have event induced subjective experiences in the form of tangible emotions; sapience is a measure of intelligence based on the capability to act which in itself is derived from judgement. Cetaceans have long been known to involve in complex social behaviour, communications, emotions and above all possess cognitive abilities which has been proven time and time again.
Looking back at the human made concept of sapience and sentience, YES they are. But on a side note, the concepts of sapience and sentience are both indoctrinated by humans and the perceptible attributed of these two qualities are equally HUMAN in their definition while in nature the actual sentience/sapience might be something entirely different and the species which appear as not very intelligent to us simply may not need to satisfy the human made attributes in order to maximise its chances of survival in nature and the funny part is we consider all other species beneath us and yet they have all been living much much longer on Earth than we have without creating self detrimental conditions.
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Hi everyone,
I was wondering if anyone could give some suggestions about:1) methods to use for mapping distribution of dolphins (and modelling using benthic habitat data) when there were no track effort recorded. The only information is a vague location (possibly GPS locations but not as accurate as today). Note, I'm referencing to data collected in the 1990s; 2) whether there is a way to compare those data with other collected in the last decade (i.e., track effort available; accurate location)...
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Thanks Bruno for your modelling suggestion.
Yes, that was already my plan for the comparison analysis.
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For a project, I have been researching the common ancestor of the short beaked dolphin and the domestic pig. Any other evidence of their relation (homologous structures or nucleotide sequences) is also much appreciated.
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The common dolphin is the name given to two species of dolphin making up the genus Delphinus. Taxonomists and cetologists usually recognise two species — theshort-beaked common dolphin, which retains the systematic name Delphinus delphis, and the long-beaked common dolphin D. capensis.
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Hello all,
I wish to determine pairwise relatedness and eventually reconstruct pedigrees for a population of dolphins using high-density microsatellites (>2000 loci/individual). However, most genome-wide estimators of IBD are optimized for SNPs. Is anyone aware of a program that can compute IBD/kinship coefficients from multiallelic genome sequence data? Alternately, does anyone have experience entering microsats into PLINK or KING?
Ideally I would like to be able to use a program like PRIMUS or CLAPPER to reconstruct pedigrees.
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Gregoire Leroy Thanks a mil
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Two species of coastal dolphins, whose groups of females-calves are annual residents and with a similar habitat use that leads them to interact in almost 75% of the time they are sighted, can establish stable social ties despite being different species?
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I’d say yes too. But it’s possible to make a photo-ID and study the Dolphin Capture History. Usually intraspecific-dolphins that are having social interactions are seen more often together. It’s worth checking if this is true in your case. KR, D
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I have received project reports Lazar et al. 2017 and Pabi et al. 2014
evaluating recent stocks of small pelagics (Sardinella aurita, S. maderensis, Engraulis encrasicaulis, Scomber colias) off Ghana, but I search published information on long-term seasonal presence and reproductive biology, as to correctly interprete dolphin (predator) presence. Anyone can suggest/provide papers? Thanks.
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Some animals like whales, dolphins, bats, and ants can produce ultra or infra sounds. Can we use these ‎waves to cure diseases like cancer?‎
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I think it is possible since even a cat's purring can aid in the healing of injured tissue
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The question relates to a steel hollow pile that is driven into a (sandy) soil. The pile is meant to function as a dolphin pile. From current literature I can find a structural damping coefficient for steel structures of c=0,007.
For this research however I'm looking for the (positive) effect on the dampingcoefficient c or dampingratio (zeta) that is caused by the surrounding soil.
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Thank you Mohannad H. Al-Sherrawi for your recommendation on the article. I've found it and will try to use it in the analysis. Are you involved or working on structural foundations yourself as well?
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Anyone who works with sea animal’s necropsy could tell me the price range for necropsying whales, sea turtles, dolphins, and sea birds? What do you think it's the best way to charge for this kind of service?
Thanks guys
Ana Paula Pires
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We are conducting all of above mentioned. Price is between 50 and 200 EUR (excluding whales which will be min. 500 EUR).
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You may consider to add these papers to your reference list. They document the presence and epidemiology of lobomycosis-like disease in common bottlenose dolphins from the Gulf of Guayaquil.
Van Bressem MF, Van Waerebeek K, Reyes JC, Felix F and
others (2007) A preliminary overview of skin and skeletal
diseases and traumata in small cetaceans from South
American waters. Lat Am J Aquat Mamm 6: 7−42
Van Bressem MF, Simões-Lopes PC, Félix F, Kiszka JJ and others (2015) Epidemiology of lobomycosis-like disease in bottlenose dolphins Tursiops spp. from South America and southern Africa. Dis Aquat Org 117:59-75. https://doi.org/10.3354/dao02932
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I wonder the same question. We are in the process to update our project as we are going to start this year. As part of the disease research component, we will pursue the molecular screening of pathogens in skin biopsies to investigate Paracoccidioides brasiliensis, which has now been postulated as the probable cause of lacaziosis/lobomycosis, and it has been referred to as paracoccidi­oidomycosis ceti (please, see paper by Vilela et al. 2016), in which one of our colleagues (Patricia Fair) has been involved. Only one well-documented study shows the uncultivated nature of the pathogen Lacazia loboi causing cu­taneous granulomas in dolphins (Schaefer et al. 2016). I my country (Ecuador) there is not a concerted microbiological and molecular clinical assessment to isolate and detected this pathogen from bottlenose dolphins exhibiting this kind of fungal lesions on the skin. We have observed these lesiones in the dolphins from El Morro Mangrove Reserve (Alava and Jimenez 2014) and we are aware of the overview and epidemiological studies in other sites within the Gulf of Guayaquil (Van Bressem et al. 2007; Van Brseem et al 2015). Thus, this is part the rationale to conduct this research, in addition to assessing persistent organic pollutants (POPs) and mercury.
References
Vilela, R., Bossart, G.D., Leger, J.A.S., Dalton, L.M., Reif, J.S., Schaefer, A.M., McCarthy, P.J., Fair, P.A. and Mendoza, L., 2016. Cutaneous granulomas in dolphins caused by novel uncultivated Paracoccidioides brasiliensis. Emerging infectious diseases, 22(12), p.2063.
Schaefer AM, Reif JS, Guzmán EA, Bossart GD, Ottuso P, Snyder J, et al. 2016. Toward the identification, characterization and experimental culture of Lacazia loboi from Atlantic bottlenose dolphin (Tursiops truncatus). Med Mycol. 4:659–665. http://dx.doi.org/10.1093/mmy/myw011
Gracias!!
Juan Jose Alava
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Before posting this question, I'd like to state that the following must not be regarded by any means to a discussion on catching marine mammals in EU seas.
Why are marine mammals (namely very common species of dolphins and pinnipeds) strictly protected in EU waters while Bluefin tunas, rare and collapsing as they are, are still apparently overfished mainly in the Mediterranean's W basin? Do you think that this has something to do with the "cuteness" of marine mammals and the fact that Thunnus thynnus is "just a fish"?
Many thanks for your contributions.
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I think to fully answer this question one would need to analyse why most western people would give marine mammals higher ethical importance than fish like tuna. Such socio-cultural construction is surely very complex. Who would eat "flipper" or his bigger brothers and sisters, the whales. To search for economic explanations is important, but it finds it limitations as whale meat is also costly, not necessarily in Europe, but Japan for example.
In the Solomon Islands every year thousands of dolphins are killed, which causes much outcries, but such outcry would never happen, when the same fate would meet fishes……, no matter how threatened….. The example of the Solomon Islands might suggest that the difference between fish and mammal is not only a European aspect.
The socio-cultural construction of what should be consumed from the ocean and what not has become the basis of strong protection efforts (e.g. Greenpeace, consumer societies which introduced the dolphin friendly tuna label). In some cases, e.g. the protection of most of the whales from getting extinct, has ecological reasons, but do we condole the extinction of the dinosaurs for example. While I speak in favour of protecting bio-diversity it is still worth reflecting, what ethical principles are behind such calls and how these ethical principles are socially constructed and if it makes differences what animal right are concerned.
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Flower, W.H. (1870) Description of the skeleton of the Chinese white dolphin (Delphinus sinensis). Transactions of the Zoological Society of London 7: 151-160.
Zoological Society of London (ZSL) who formerly published Trans. (now J. Zoology), through Wiley Online Library charges USD 38.0 for this 147 yr old paper on dolphin anatomy, all the while brandishing the motto "Let's Work for Wildlife", no less. ZSL should be ashamed: many genuine Workers for Wildlife are volunteers in developing countries and cannot afford paying for 2 centuries-old scientific papers. Author W.H. Flower would surely turn in his grave if he knew.
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Dear Koen Van Waerebeek,
I kindly request to send a copy of this paper to me, too. Thank you
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 I am working on the interaction of Irrawaddy Dolphins and fishing gears in a bay in the Philippines. Too much number and kinds of gears sometime accidentally entangle and kill dolphins.  I need suggestions from experience on management approach that would keep dolphins from entangling in nets and ropes at the same time will not greatly affect the source of income of the fishers?
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Thank you Arvind and Shawn. Yes, I will go through these references and web sites. This are valuable inputs! We hope to move on this situation and help save and manage fishers and dolphins. Will keep in touch.
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I`ve found a epiphyses from a dolphin vertebra in the Sarmatian deposits.
This fossil can be identifyed?
Thank you in advance !
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It's a pity because your photos are devoid of any scale... They could be also clearer. However, I suspect that it could be a dolphin vertebra, it looks like a lot of similar ones collected in the Sarmatian areas of the outer Romanian Carpathians areas.  But, this specimen was very young, his life wasn't long at all! Pay attention, this is not an epiphysis, For a clear systematic determination, in my opinion vertebras are not very useful: skulls or limb bones are by far better.  
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This is blood vessel from dolphin stomach with a lymphocyte and unidentified cells (arrow heads).
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Basophils
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First photo is electron micrograph of dolphin stomach infected with a digenean parasite, and the other two are electron micrographs of intestine of Sprague-Dawley rat experimentally infected with Anisakis spp.
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 These are the septa ted macroconidia and microconidia of dermatophyte fungi 
 namely  may T.metagrophyte .
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I was told that females of Atlantic Spotted Dolphin tend to get more spots after going through pregnancy, due to hormonal variation, in the same way some women notice changes in pigmentation during pregnancy.
Any opinions on this? 
I´ve been looking for papers regarding this topic but found none myself...
Thanks!
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its not true.Spotted dolphins are born without spots, they are dark gray on their backs graduating along their sides to a white belly. At approximately four years of age they begin to get spots. As the years go on, black spots fill in their lighter bellies and then upward, while white spots fill in along their upper sides and back. The older adults become so fused with spots their bellies appear almost black with white specks Female Spotted Dolphin reach maturity around 12 years old.
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I want to measure chlorine specific IgE in dolphins.
Thanks for help
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If I were you, I would contact Dr. Todd O'Hara, DVM, Ph.D, A.B.V.T.
Professor of Veterinary Toxicology & Pharmacology at UAF in Faribanks, and see who he recommends. Email tmohara@alaska.edu
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Hi,
I would like to know if any of you have a good experience with the pop-up tags from Desert Star, particularly GEO 3D. I intend to use them with dolphinfish. Thanks
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Thank you! I have contacts from there, just wanted opinions from researchers, particularly on reliability of data recovery.
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Has there been any evidence of Vemco acoustic tags harming or negatively affecting local cetaceans (specifically dolphins)?
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No experience with Vemco, but I would remind that "harm" is not limited to a lethal result. There is a a full range including also complete, to partial hearing loss, vocal shifting responses and sleeping disorders. Noise effects would depend on the sound pressure level as well as the exposure time to the noise.
A quick check on Vemco's website shows devices both receivers (passive) as well as transmitters (active). On the acoustic transmitters tag section, their freq are 69 kHz and 180kHz with an intensity ranging from 136dB to 162dB. I do not see much of a risk of overlapping with vocal repertoire compared with a probable partial overlapping with echolocation; however with these intensity levels, I would not consider attaching these devices (transmitters) to any cetacean.
Depending on your goals, there are alternatives to active acoustics, like passive tags or loggers that can record diverse type of data and detach from the individual after some time.
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how the meaning of these images?
This images is result from processing with Software Matlab with Syntax FFT to Specgram
Thank You For Attention
Regards 
Lubis
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I recommend you to read a brief introduction to sound analysis, for example:
A good reference book also can be
Au, W. W., & Hastings, M. C. (2008). Principles of marine bioacoustics (pp. 121-174). New York: Springer.
ISO 690
I guess you are trying to analyze your dolphin whistles using contour analysis, there are many publications on this technique, you can check this recent ones and track back to the older ones:
Gannier, A., Fuchs, S., Quèbre, P., & Oswald, J. N. (2010). Performance of a contour-based classification method for whistles of Mediterranean delphinids. Applied Acoustics, 71(11), 1063-1069.
Ferrer-i-Cancho, R., & McCowan, B. (2009). A law of word meaning in dolphin whistle types. Entropy, 11(4), 688-701.
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Whether the Software Raven pro 64 bit 1.5 (Bioacoustics Cornell Lab of Ornithology USA) is able to analyze the spectrum of dolphins with specific?
logarithms, frequency range, and the range of intensity ??
Thank You ,..
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Hi Russ Charif  Thank you very much for your suggestion and information to me .
i will be message you in research gate , about my problem using Raven Pro.
Regards 
Muhammad
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I'm looking for references to vocalizations of Stenella attenuata. If anyone has any references, please let me know!
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There are two more papers dealing with Stenella sounds, even though not S. attenuate:
Herzing, D. L. (2014). "Clicks, whistles and pulses: Passive and active signal use in dolphin communication." Acta Astronautica 105(2): 534-537              
Lammers, M. O., et al. (2003). "The broadband social acoustic signaling behavior of spinner and spotted dolphins." J Acoust Soc Am 114(3): 1629.
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As for whistles we have the visual inspection method and others quantitative ones to classify them in sub-types, I am looking for any already published method to do the same with burst-pulse vocalizations in dolphins.
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In addition to the other answers, I'd suggest to explore the use of cepstrum analysis to reveal the pulse rate and pulse rate modulations within the bursts. 
Gianni Pavan
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Fish bones regurgitated by a dolphin included very fine, complete, delicate, paper-thin long jaw bones - among other complete bones of fish. This would be difficult to explain if the stomach of a dolphin contained acid with a low pH.
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Dear all, some marine mammals vomit hard remains of their prey. For example, it has been reported in "residential" bottlenose dolphins in Ireland but also in sperm whales and in seals. If bones are from vomits usually they haven't been exposed enough time to stomach acids. These prey remains usually haven't passed to the second stomach (which is were the chemical break down happens) and it'd normal that bones are in quite good condition, may be broken. With seals might occur a different situation as they only have one chamber and both mechanical and chemical digestion occur in the same place. 
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I need to find a program that can track the movements of a bottlenose dolphin in Belize. The video was taken from drone from a moving boat. The program would need to have the capability to track the movements of a video that is not fixed on one location such as a tank. The program would need to be able to follow the movement of the animal in the video, move with the video, and create a downloadable track. 
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You can also try AnyMaze (expensive). There is also IDTracker, which runs on Matlab 2014 or higher, which is free. You need to download and compile it. 
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About 20 percent of the bottlenose dolphin's body weight is blubber, Since one of its function is to insulate the body in an aquatic environment, I was wondering if anyone has studied the correlation between blubber tickness and water temperature ? Or is their any study on body shape variation vs water temperature?
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Dear Martin,
There are a number of things that determine the insulation of blubber, thickness is definitely one of them, however fat/water content is equally important. There has been a study in pinnipeds which might give you some more information on this.
I hope this helps.
Best wishes,
Tessa
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Irrawaddy Dolphins Behaviours. Thanks
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You will find some scattered informations across the following publications. I will just add those which have not been mentioned before by the colleagues:
Parra (2005) Behavioural ecology of Irrawaddy, Orcaella brevirostris (Owen in Gray, 1866), and Indo-Pacific humpback dolphins, Sousa chinensis (Osbeck, 1765), in northeast Queensland, Australia: a comparative study. PhD Thesis.
Stacey & Leatherwood (1997) The Irrawaddy dolphin, Orcaella brevirostris: a summary of current knowledge and recommendations for conservation action. Asian Marine Biology 14: 195-214
Smith et al. (1997) Investigation of cetaceans in the Ayeyarwady River and northern coastal waters of Myanmar. Asian Marine Biology 14: 173-194
Jensen et al. (2013) Clicking in Shallow Rivers: Short-Range Echolocation of Irrawaddy and Ganges River Dolphins in a Shallow, Acoustically Complex Habitat. PLOS ONE 8: e59284
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I haven't found yet any reasonable explanations for this.
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Hi Anisul, most causes have been exposed. Perhaps you should narrow your question more to be also more specific in the answering. It seems you are asking about strandings of living individuals (not carcases) but it is not clear to me if you are focused on single individuals or mass strandings. Death is just part of life and as a process it can lead to weak individuals (due to whatever is the cause /trauma/diseases/etc) to strand and die. As mentioned the process can be induced by human activities as well.
To the list of known causes inducing strandings I would add also:
- forced strandings (in some areas in the world, the captive industry uses this technique to trap individuals and the number of affected individuals may be higher than the removed individuals from the populations).
- collisions (see the attached paper). Internal lesions induced by vessel collisions may result in live strandings despite the lack of external evidence.
- aggression; Orcas and even bottlenose dolphins are know to interact with other cetacean species including predation, but also interpopulation clashes (e.g. feeding site competition) and even at intrapopulation level you may find violent practices that can result in trauma on single or multiple individuals. These lesions may not be "visible" externally, requiring careful removal of skin/blubber layers to assess the underlying evidence.
- acoustic trauma was mentioned as well but it may be useful to keep in mind that it is a list of diverse sources. To say the least, you may need to include fishing interactions (as at least in Chile, where some fisheries use explosives to fight sperm whales and other cetaceans that interact with their longlines); seismic studies that use loud equipment affecting wildlife (not only cetaceans); navy/military practices as the use of LFA, but also regular practices with explosives at seas without necessarily considering the local abundance of cetaceans (e.g. highly productive coastal upwelling sites); constructive sites (e.g. ports and mining projects among others) may include local explosives as well as pillar hammering when building docks among sources of high acoustic pressures that may affect cetaceans. The trauma can be direct (damaging organs) as well as producing uncontrolled ascent during deep diving (inducing bends) and indirect midterm effects as diminished acoustic capabilities lowering hunting performance and thus the capability to cope with changes on prey availability.
- pathology has also been commented but you have to keep in mind that it is quite diverse as well. Parasite loads, fungal/bacterial/viral infections, toxics (e.g. heavy metals from mining waste or pesticides used by salmon farms) are just some factors that may affect cetacean's general health. You may find syndemic sources affecting an individual as well the entire pod's general status resulting in live strandings. I agree, Van Bressem et al have contributed largely on this field.
- sea bottom shape was also mentioned by Sylvain. Perhaps it is useful to explain as well that there are local geographic factors to take into account that may pay a role. Like areas where large tidal changes may trap cetaceans in the coast (e.g. San Sebastián in Argentina) or sites that expose special difficulties to overcome and thus work as a filter removing weak/old/sick individuals from the pod (currents, storms, etc) sometimes even seasonally.
- food access: cetacean metabolism is like a sport engine that provides a lot of work power but at high energy expenses. Bad relationships between increase needs (e.g. colder weather) together with decreased access of food (e.g. local overfishing or natural causes like ENSO), may lead to rapid depletion of energy storage, weakness and live strandings.
Many of these factors can affect pod's members in sync, resulting in group live strandings.
Perhaps the general answer is that there is no single "magical" cause. Each case deserves attention to assess its own cause. Necropsies are needed as samples have to be analyzed. Many times we see people driving fast conclusions at the beach before the needed assessment, specially if a camera is nearby.
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I have run across a number of anecdotes of this growth affecting some Tursiops aduncus bottlenose in/around the Broadwater estuary on the Gold Coast, Australia, around 10-15 years ago (2000-2005). No-one has been able to provide me with pictures. The growth protruding from their mouth made it impossible to accept food from boaters who tried to provision them. Not surprisingly, they disappeared fairly quickly.
I've found one passing reference to a similar condition but the study simply made mention of a male, on its own, with the growth, and didn't study or investigate further.
I'd be interested of any other sightings of such a condition, any thoughts on what it might be, or any photos.
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Since you don't have photos, it's difficult to know what the cause of the condition you mention. However, the video and photo from Simon seems to me to be stalked barnacles. They have been described in many cetaceans, and I've found in franciscanas (Pontoporia blainvillei) from my area. You can see a photo of it at https://flic.kr/p/rPR6qt
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I am extracting hormones from sea lion lipids and most of my samples have solids precipitating out, which I haven't seen with dolphins. I'm wondering if there is some property of sea lion fat that would cause this? I haven't come across a paper that explains what I am seeing. Thanks!
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I have attached the picture of the humpback dolphin taken past November in the Persian Gulf as part of my research there. I am not really sure if this type of mark could be caused by a propeller as it looks like that there are marks on the body. Has someone observed something similar in other dolphins?
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To me it looks like the animal was injured by some type of fishing gear.  Sam Ridgway
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I have attached the picture of the humpback dolphin taken past November in the Persian Gulf as part of my research there. I am not really sure if this type of mark could be caused by a entanglement in a gillnet. Has someone observed something similar in other cetaceans?
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Hi Bruno, no doubt about it. This individual presents the remains of a propeller strike of at least two years old (the scar is not longer whitish). I have seen these wounds quite frequently in Chilean Patagonia with the increasingly busy fjords due to the salmon farm expansion. I have several photos just like this one but mainly on L. australis. Despite the photo is not very big, you can see at least four contact points all separated by the same distance. Your photo is great since it almost replicates the position the dolphin had a second before the collision happened. The cuts are at the same distance but the two biggest are also at the same depth. They are not in straight lines but slightly curved both in the same manner regardless of the amount of mass involved (active source).
In contrast, in my experience net wounds tend to be located at the closest section to the flukes and frequently they include longitudinal cuts on the flukes themselves. The net slides back since the peduncle gets thinner towards the tail but then can get stuck on the tail producing the cuts at that level. The lesions of this individual are not grouped close to the tail but positioned at same distance from each other regardless of the thickness of the peduncle. Also the cuts from the surface (dorsum) present a forward direction. They are not even vertical but towards the front of the individual. Whatever did these cuts, had "its own energy" in order to achieve that direction and the high speed needed as well to counterfeit the movement of the dolphin. Anybody with experience performing necropsies on cetaceans can confirm how hard is to cut at this level of the body. The tissue is very dense. These lesions are not due to a passive source. Nets tend to produce only a superficial damage unless getting stuck on structures like flippers or the tail due to their dragging effect. Therefore the cuts, when due to nets, tend to cut towards the back of the affected individual.
In conclusion, considering the direction of the wounds, their period, number and slight curved shape, we have no nets here but the "classic" small propeller blade wounds in perhaps the most frequent site where dolphins get these lesions. I am always surprised how some individuals can survive and keep up with these wounds but at the same time we do not know the rate of mortality. Perhaps these cases of survival are only a small percentage. We simply do not know.
It is important to report these collision cases to IWC and IMO since there is a worldwide database collecting information about this threat to both wildlife and vessels. Speed and/or path restrictions can be implemented in areas with high rates of collisions. Governments are required to report these cases to IMO but the details of this procedure depend on each country.
I recommend you to check some of the pics we posted in this paper:
kind regards
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My Sp1K since their purchase at passage 8 have been very slow in growing, but now they stopped. We used all medium and reagents as raccomended, they are Mycoplasma free, but they are stopped from about 10 days, now  they are at passage 13 is senescence possible already in this cell line?
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Hi  Willems, I don't have experience with this line but what you describe is the classical response of a cell line to an FBS that they do not like (they start growing but gradually begin to stop over time).
Cell lines (generally) do not become senescent as primary cells do so this is unlikely (especially in such a short time scale and without the "classic" senescent phenotype such as increase in cell size, "fried egg" phenotype etc).
I am guessing that you did not purchase FBS from the supplier of the cells and that you are using the FBS you already had "in-lab"?
I would purchase a small (100 ml) amount of a good quality FBS (such as from Gibco or ATCC) and try to grow some of the cells in this to see if it makes a difference (as mentioned above supplementation with some conditioned media may also help).
Also it is worth logging the problem with the supplier of the line (they may give you more cells or point out where you are going wrong).
Sorry I can't be more help,
Gary
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I observed horseflies (Tabaniidae) biting bottlenose dolphins (Tursiops truncatus) in a caribbean mangrove area. I can't find reports on bloodsucking insects predating on completely aquatic mammals (dolphins, whales, manatees). Does anyone have any information/paper about the subject?
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There are tabanids that not only feed on crocodylians, but hold on when the reptile leaps for food or even submerges for short periods. I have observed this in wild estuarine crocodiles, Crocodylus porosus.
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Am devising a campaign for project, any extra info would be greatly appreciated, especially surrounding their dietary requirements/habits and techniques used to assess this. Thank you
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Hi Hannah. Do not forget that mostly you are talking about a coastat species, and that interactions of the species with artisanal fisheries and fishing gears like trammel and gill nets are quite strong in most of the areas studied so far. So I will begin with the spatial description of the fisheries in terms of fishing grounds, its vulnerarbility for bottlenosed dolphins attacks, target species both for fisheries and as food for the dolphins, and finally distribution and abundance of dolphins in the area where the MPA is suposed to be declared. This will give you an insight of the potential future conflicts with fishermen and guidelines for the zoning of the MPA. These two aspects working together are a critical point in the future failure or success of the MPA to come. Yours,
Pep
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They can form groups of >200 individuals, engaging in different activities.
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As long as you can randomize the group selection (i.e. you don't select groups because they are easy to see or apparent because they are doing something interesting), focal group sampling with ad libitum could certainly work. It all depends on your questions and hypotheses of course. Good luck!
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I am trying to categorize burst-pulse sounds of dolphins within a data set, and am having trouble figuring out how to determine the pulse repetition rate of a sound. Raven (Cornell software) does not seem to have any instructions on how to do it in their software, but is this something another software can do? Can you count the number of pulses visually? Do I need a code, for example in Matlab? Any help would be greatly appreciated!
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Hi Christina, I have been working with bottlenose dolphin burst pulsed sounds during the last years and I understand your need to find to define the differences between sounds. The existing literature is vague because burst pulses have been traditionally discussed in terms of their sonic properties and is difficult to measure when calls are classified solely by ear or acoustic features. Terms such as “screeches,” “gulps”, “brays”, "barks", “quacks”, “yelps”, and more… commonly used to describe and distinguish burst pulsed sounds can result in misleading conclusions, as they primarily describe the subjective impressions experienced by human listeners. Additionally, the way the vocalizations are analyzed, and the authors tendency to split or lump, also affects the interpretation of repertoire size. For example, a bray is formed by two different types of burst pulsed sounds however a bark is only one... In one of my studies I have classified the burst pulses based on the duration of the sound (in the oscillogram), in other studies I also measured the Interclick interval or interpulse interval manually (for this I have used a software called soundruler).
As a start, I suggest you to form classes of burst pulsed sounds on the basis of structural characteristics (for example I used the duration), this would lead to more meaningful comparisons between categories.
Good luck!
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Does anyone have photos of malformations on the fluke of bottlenose dolphins and is interested in discussing it? Last year there was a stranding of a young bottlenose with a malformation on its fluke. Since then I have been trying to gather information and references that might help in order to prepare a short note (hopefully!). Does anyone want to share information and be involved in the publication?
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Here is a link to a CT scan of a section of vertebra from a juvenile right whale