How the August 24th Mass Stranding Involving Pilot Whales in Cape Verde Is Connected to the Recent Mass Stranding in Florida

Mass Stranding, Cape Verde , August 24, 2012

Over a period of roughly 2 weeks we had 4 mass strandings: Cape Cod (dolphins), Scotland, Florida (previous blog link) and Cape Verde (pilot whales link and link). The mass stranding of 17 pilot whales on Santa Maria beach, Cape Verde did not get much media coverage and we missed it too. Thankfully, our friends provided info about this stranding so we decided to investigate it too.

Mass Stranding in Cape Verde

 

The Cape Verde’s mass stranding took place on Santa Maria beach during early morning hours on August 24, 2012.  The time of stranding is very important as you will see below. This stranding was handled in the best possible way, all whales were refloated, not one whale was lost. The group consisted of 17 whales including both adults and babies. Compared to Florida’s stranding where whales were butchered and Scotland where 16 whales were lost, in this case rescuers managed to save everyone. This rescue was handled by Turtle SOS Cabo Verde, locals and hotel guests and we are extremely impressed and happy how it was handled. If you have a moment please give SOS TARTARUGAS (web and Facebook) a shout on work well done!

Connection to Mass Stranding in Florida

Now, here comes an interesting part. This stranding appears to be connected to Florida stranding in two ways. First, both involved pilot whales. But second is that both happened during or after the same “hazardous operations” that took place in 3 areas:  Florida, offshore and the third one only 1044 km from the Cape Verde stranding site (see the map from our previous blog post link).

The new map above shows the third area and the “hazardous operations” in that area (based on info we have) started around 8:07 am UTC on August 24, 2012. While we are trying to confirm exact time when whales were discovered it appears that they were found shortly after stranding around 7: 15 CVT (which is 8:15 am UTC) because they stranded in populated area.

Now so far it appears that whales basically stranded shortly after the start of “hazardous operations”. Now, we do not know whales’ exact position the moment when “hazardous operations” started, but we know the distance between stranding site and the area and also speed of sound underwater.

In case anyone is interested in calculations here is a formula (link):

C(T,P,S)=1449.2+4.6 T+0.055 T2+1.39 (S−35)+0.016 D

where:
C is in m/sec,
T in ° Celcius,
D in metres and
S in parts per thousand.

This is a very simple calculation, that does not consider propagation and many other factors, but it works to demonstrate our point. Let’s say the water temp was 25 C, depth was 200 meters and salinity was 35. The we get underwater sound speed of 1736 m/sec which translates into 6249.6 km/h, which in turn means that if whales were somewhere close to the stranding site when “hazardous operations” started they were able to hear it 10 minutes after the onset of “hazardous operations” i.e. around 8: 17 am UTC. Again these calculations are very rough and many other factors that are not taken into consideration could have made speed of sound even faster.

However, this opens the intriguing possibility that in order for stranding to be triggered in some cases whales might not even need to be very close to the source. If whales have had previous exposure to this type of sounds and consider them dangerous, hearing the sound in a distance might trigger flee response leading to stranding.

Of course we recognize that there are many assumptions in the possible scenario we are offering here. But what we find very curious is that both strandings are just way too suspicious to be another innocent coincidence. First we have similar species. Next we have similar types of “hazardous operations” happening and affecting these species causing mass strandings. These “coincidences” alone should warrant an investigation into this matter.

By the way, luckily for whales by 9:27 UTC “hazardous operations” were ceased, that is probably why they were able to make it and not restrand again.

Now the question is: WHO IS GOING TO INVESTIGATE IT AND WRITE THE OFFICIAL REPORT?

Note: pilot whales swimming speed can be between 0.2-14.5 km/hour.

 

 

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