"Porpoise-friendly" echo-sounder design project, University of Southmapton

[trapezeartist]

I would echo the previous comments, and my answers to the 7 questions would be much the same (except different boat and different make of sounder to some).

There seems to be little doubt that porpoises, dolphins and small whales like boats. Boats have echo sounders. Ergo p,d, and s w may even like echo sounders and certainly show no sign of disliking them. As you say that there is an EU directive that is displaying signs of having been written by people who don't know what they're talking about (am I surprised?!), perhaps a more useful first study would be to scientifically determine the effect (if any) of echo sounders on these animals. (You may also like to check out the effect of echo sounders on sea horses.) (Then if you have time left, you could measure the effect on pseudo-conservationist divers.)

 

[nimbusgb]

drifting

Thank you all for your replies.

The idea of the project comes from some EU directives for 2012 that were proposed about sound pollution in the ocean, and one of them was about high frequency impulsive sounds, such as echo-sounders, being disruptive to marine mammals (especially porpoises). However, these documents were not wrote by acousticians which is why part of our project is also trying to determine wether echo-sounders would actually be harmful/annoying to porpoises and other marine mammals. From my understanding, the reason it is suspected it might be disruptive to them is that porpoise echolocate(/communicate) at similar frequencies (115 kHz if I remember well) and their clicks are also narrow band short pulses.

So, thanks again, all the information is useful to us because we know little about boats. We knew that dolphins often came to play around boats but we heard that porpoise tend to have a very elusive behaviour.

Sorry SouthamptonStudent but I am appalled that that paragraph was written by a 4th year University student. What a sad reflection on the British education system.

1. What type/model of boat do you own?
Benetteau 11.5m

2. How often do you use your boat?
not enough

3. What model is your echo-sounder?
Raymarine ST60+ and Echopilot platinum F.L.S

4. When out to sea, do you have your echo-sounder on continuously?
Yes depth, no FLS

5. If not, in what circumstances do you turn it on?
FLS when in anchorages or generally below 10m depth

6. If you do, do you feel it is necessary to have the echo-sounder on continuously (for example, even in deep waters)?
Theres no simple way to turn it off since its powered from the seatalk bus.
It draws so little power that its barely worth worrying about.
I would be happy to have it linked to the GPS and charting system so that its off over depths of 99m

7. If you were to replace your echo-sounder, do you think you might opt for a porpoise-friendly one if it were available?
Dolphins don't seem to mind depth sounder and I have never seen the sea littered with upturned or confused porpoises so no.


I wonder what the OP's reaction to ultrasonic anti-fouling will be when he learns about it?

 

[RAI]

Acoustic range

According to this:-

http://www.dolphins.org/marineed_acoustics.php

Porpoises do have an acoustic range that reaches to the 200 kHz commonly used by depth sounders, while dolphins do not. Maybe that's why dolphins come to play but porpoises keep their distance.

1. CE 38 11.4m
2. Continuously
3. Raymarine ST 60 + Echopilot FLS
4. Yes, whenever the charted depth is less than 200 m (they don't register greater depths reliably).
5. Charted depth < 200 m.
6. I'm told submarines can only hear sailing boats reliabably via their depth sounder signature. I'd rather not have one surface undernieith me.
7. Yes, if it didn't cost a fortune and still warned submarines of my presence.

 

[pvb]

Sorry SouthamptonStudent but I am appalled that that paragraph was written by a 4th year University student. What a sad reflection on the British education system.

Don't you mean "wrote by"?

 

[penfold]

What behaviour does a distressed delphinidae display?

I do not know; subjectively, there was no difference between their behaviour around a boat with E/S on and that around a boat without, that is to say they typically approached our vessel, frolicked for 5-20 minutes in the bow wave, then buggered off.

 

[SJF]

1. What type/model of boat do you own?

Moody 31 Mk1

2. How often do you use your boat?

Approx two weekends per month and a couple of weeks during the summer.

3. What model is your echo-sounder?

Navman Multi 3100

4. When out to sea, do you have your echo-sounder on continuously?

Yes

5. If not, in what circumstances do you turn it on?

N/A

6. If you do, do you feel it is necessary to have the echo-sounder on continuously (for example, even in deep waters)?

Its a navigation tool and so stays on all the time. I'm also constantly logging depth data for the teamsurv project.

7. If you were to replace your echo-sounder, do you think you might opt for a porpoise-friendly one if it were available?

As others have said, I'd want to see evidence to suggest that such a thing was necessary and it would need to be priced the same as 'unfriendly' ones.

 

[noelex]

I will "echo" other comments.
The last sail I had a pod of dolphins join me for about 6 hours.
If they were bothered by my depth sounder (which was on) there was plenty of open ocean, with no boats, they could have chosen to swim in. Instead they kept me company.
I think they liked the bow wave more than my conversation, but if the depth sounder caused them any discomfort or disrupted their communications (there were several in the pod) why did they stay?

 

[oldfatgit]

Just for interest try watching this http://www.youtube.com/watch?v=QS5P6yUEp_4&feature=related and this http://www.youtube.com/watch?v=1tpC6nWTQI4&feature=related where the sound that the dolphins didn't like was the engine oil/temp warning alarm. Don't know if helixkimara's echo sounder was on though.

Anyway, answering the questions:

1. Tradewind 35

2. Couple of times a month and 2 to 3 weeks during the summer.

3. Tackick with tridata transponder

4. Yes, always find the depth data useful for navigation and cannot turn it off without turning off everything else.

5. NA

6. See answer to Q4.

7. Insufficient information to consider that I do not have a porpoise friendly system.

So, enjoy your project, but you have a number of hypothesis to test before confirming that there is a need for a special system. If there is nothing in the literature then you will have to test the hypothesis by developing a repeatable test which shows a consistent change in behaviour by porpoises when in the presence of an echo sounder. I suspect that this will be the challenging part of your project, not developing a system which works at a different frequency. Once you have your test then you will be able to explore the acoustic spectrum in order to find out what doesn't bother porpoises.

 

[Bert Large]

Southampton Student, could I politely suggest that in order to protect porpoises your time may be better spent lobbying the EU to ban midwater pair trawling for Bass in the English Channel where they are often caught as a by-catch.
The UK government did ban UK boats from trawling for Bass inside the 12 mile limit but it is not within there power to stop foreign EU member state boats from trawling for bass up to 6 miles from our shores. What a ridiculous state of affairs

 

[Razorfish]

Southampton Student, could I politely suggest that in order to protect porpoises your time may be better spent lobbying the EU to ban midwater pair trawling for Bass in the English Channel where they are often caught as a by-catch.
The UK government did ban UK boats from trawling for Bass inside the 12 mile limit but it is not within there power to stop foreign EU member state boats from trawling for bass up to 6 miles from our shores. What a ridiculous state of affairs

Ah, you assume that the EU listen to sense.

From past experience I predict that once this EU directive is translated into UK law our Statutory Nature Conservation Agencies (Natural England, CCW SNH etc.) will use it to make life difficult for us and other sea users (the fishing industry will be top of their list). Although, how anyone is going to police any new rule is beyond me.

By the way, I agree wholeheartedly with banning midwater trawling for Bass in the Channel - its criminal.

 

[RAI]

On my last crossing Boulogne to Eastbourne I observed several french trawlers fishing in the UK's side of the TSS. The UK CG were helpfully warning shipping on Ch 16 to watch out for them.

 

[Bert Large]

Ah, you assume that the EU listen to sense.

From past experience I predict that once this EU directive is translated into UK law our Statutory Nature Conservation Agencies (Natural England, CCW SNH etc.) will use it to make life difficult for us and other sea users (the fishing industry will be top of their list). Although, how anyone is going to police any new rule is beyond me.

By the way, I agree wholeheartedly with banning midwater trawling for Bass in the Channel - its criminal.

No, I don't believe the EU listen to anyone who speaks sense, only to those who have the means to stuff more brown envelopes & thrust them into their hands

I was hoping such quangos as Natural England & Finding Sanctuary would be included in recent the "bonfire of quangos"

 

[blackbeard]

.....
1. What type/model of boat do you own? British Hunter 245 (25' bilge keel sloop)

2. How often do you use your boat? about 30 days/year

3. What model is your echo-sounder? Garmin GPS with fishfinder; the fishfinder is a very good echo sounder. Fishfinders may use more than one frequency

4. When out to sea, do you have your echo-sounder on continuously? yes, it's on when the GPS is on which is always

5. If not, in what circumstances do you turn it on? see above

6. If you do, do you feel it is necessary to have the echo-sounder on continuously (for example, even in deep waters)? see above, it would in any case be on if I were anywhere near a submarine exercise area

7. If you were to replace your echo-sounder, do you think you might opt for a porpoise-friendly one if it were available? I would need a definition of "porpoise-friendly" and a clear argument as to why one type of sounder is friendly and another isn't.

Thanks in advance.

As has already been pointed out, information on yacht echo sounders is relevant only if you know what upsets, or doesn't upset, cetaceans; and a study of cetacean behaviour will be far more challenging than a study of echo sounder use.
Also, as an ex Southampton Uni student, I would suggest that you get your posts checked for English grammar before posting.