Dolphins - Science topic

Ljubomir: Excellent. Thanks.

A couple of webpages that may help with the interpretation of box plots:

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

Optimum salinity around 36 psu is reqd., but NH3 and DO level to be considered

Rough-toothed it is.

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.

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

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

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

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.

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.

Thanks Bruno for your modelling suggestion.

Yes, that was already my plan for the comparison analysis.

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.

Gregoire Leroy Thanks a mil

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

I think it is possible since even a cat's purring can aid in the healing of injured tissue

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?

We are conducting all of above mentioned. Price is between 50 and 200 EUR (excluding whales which will be min. 500 EUR).

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

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.

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.

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.  

Basophils

 These are the septa ted macroconidia and microconidia of dermatophyte fungi 

 namely  may T.metagrophyte .

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.

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

Thank you! I have contacts from there, just wanted opinions from researchers, particularly on reliability of data recovery.

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.

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.

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

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.

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

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. 

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. 

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

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

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.

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

Are these helpful?

To me it looks like the animal was injured by some type of fishing gear.  Sam Ridgway

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

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

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.

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

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!

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!

Here is a link to a CT scan of a section of vertebra from a juvenile right whale