I would suggest contacting suppliers such as Wildlife Computers with your particular application. They should be able to help with this application, which seems fairly straightforward. Good luck!

You can do this with a wildlife computers pop-up tag. The problem you will have, and I assume you will have this with any companys tag is that battery life is seriously depleted by time spent floating on the oceans surface, looking for and transmitting to a satellite in range. So while you can retrieve the tag, reset it and redeploy it, it will have a limited battery life. Tags can be rebatteried by the company, but this is also an expensive process.

Thank you for your answers! I asked the question after contacting suppliers wildlifecomputers and Lotek. According to their answers, the PSATs are not re-usable, i.e. can not be reset and redeployed. Therefore i am intrigued by James Andersons answer! Do you have experience in "re-using" PSATs? Again thank you for the answers!

I suppose I was was more answering your question in theory, not considering a full deployment where the burn wire has been actioned.

As is detailed in the Wildlife Computers MiniPAT User Guide, the status of a tag can be changed from standby/deploy/shutdown assuming you have the tag in hand. We have had tags that have been activated (probably by coming into contact with sea-spray) during field work, that we have subsequently put back into standby, pending actual deployment.

Thus my thinking in my answer was that you can take a tag that has been deployed for 48 hours (as you suggested), connect it to a PC and put it back into standby mode. The archived data remains archived.

This would require the tag to be extracted from the animal, as opposed to being released via a burn command.

Obviously, if Wildlife Computers have told you this is not the case I will defer to their expertise.

Actually, James' response is correct, and I am a little surprised at WC's response. We have had several PSATs for our swordfish program "re-batteries", at a cost of 750 USD, if I recall correctly. We have also had good luck with the recycled PSATS, with deployments extending over several months. I would reconfirm this with WC, because their initial response does not seem to be correct.

Hello,

The new PSATS (MiniPAT) from WComputers are not longer 're-baterries'. They offer you a discount in your next purchase (half the price, c. 2000 US dollars).

Other company to contact is Microwave, but I guess they work pretty much the same. There are other guys (Desert Start Systems) that are working with magnetic field and solar tags that maybe you will like to check. I have very little info about how their tags are working.

Recycling PSATs: as James said, even if you 'recapture' the tag when it has started its transmission (high energy consuming), the tag will have corroded the 'pin' (the release mechanism that link the tag with the dart/tuna), so again you will have to send the tag to the company and not sure if the rebuilt only the pin. So unless you catch the tuna and recover the PSAT without breaking the pin, it will be impossible.

Notice that geolocalitation (using light, temperature and depth) is not perfect and there is an error (depending also were you are deploying them).

pc

My experience with replacing the batteries was with the Mk10, not the newer small units.

Yes, your are absolutely right. The issue is that they are not longer producing he MK10.

We have recovered many PSAT tags (both Wildlife Computers and Microwave Telemetry). I am disappointed that the new tags cannot be re-deployed. However, I assume it would still be worthwhile to recover a tag to get 100% of the archived data? After popoff, it is important to follow the daily ARGOS location updates to provide a "breadcrumb" trail to the tag's final location and make sure you go looking for it as soon as you possibly can (to ensure that your final reported location is near the actual location). It also helps if you can predict wind and current. For example, deploying a tag off the windward coast of Oahu usually means that the tag will drift inshore after popoff. Deploying a tag in the Gulfstream usually means you'll never see it again.

There are several data-logging companies that produce time/depth recorders. These can be coupled with satellite tags (e.g. SPOT) and radio transmitters to make a fully recoverable tag that will sample at high frequency. You could probably get quite a lot of life out of the SPOT and radio transmitters and hence recover/deploy the same package several times. You would have to set up your own release system, but we have done that for pelagic sharks. Another plus is that you will probably get at least a one second sampling rate.

The SeaTag-MOD PSAT tag from our company (Desert Star Systems LLC) is re-usable.   The tag is primarily solar powered, and a plug-in section provides re-usability along with the release mechanism and an optional battery for long darkness endurance.  On tuna, you probably won't need the battery as tests such as by Willy Goldsmith (VIMS) on buefin tuna lately have shown that the solar powered tag generally runs in an energy surplus mode.    

Recover and re-use is actually quite common for this tag; in the case of a research group in the Great Lakes they are seeing near 100% recovery and re-use.  But it also holds true in some oceanic applications, such as with tiger and hammerhead sharks tagged by Neil Hammerschlag in the Bahamas.  

There are several practiced methods of recovery.   One involves the use of rather inexpensive (~$500) radio direction finding equipment as described here:

here http://www.desertstar.com/knowledgebase/doku.php?id=appnotes:radio_homing_of_a_seatag_for_recovery_at_sea

This works quite well when a tag is within boating range. The latest Argos reported tag position is used as the search starting point, and the kit will take you to the tag from there.

In other cases, we have seen the use of social media, such as in the case of a tag that Argos showed had drifted up somewhere along a 1km stretch of coastline on Eleuthera Island, Bahamas.  A local beach comber saw the post, and guessed two spots where the tag might be. She quickly found it at the second spot, in the process retrieving a full time series data record of over a years worth migration of the shark.

Finally, label printed on the tags has proven quite effective; with multiple tags recovered and then re-used.

On the related issue of localizing tuna to specific oceanographic features, I recommend the work of Bruce Pohlot at RSMAS, U Miami. He used the better location estimation accuracy available through the magnetic field intensity measurements of SeaTag-MOD and SeaTag-GEO to show that sailfish moved in a very targeted way to the convergence zone around an eddy.  See this link:

http://desertstarsystems.businesscatalyst.com/resources/general/BPOHLOT_UMRSMAS_PRESENTATION.pdf

The magnetic method of the SeaTag devices uses the north-south intensity gradient of the earths magnetic field.  The gradient is location specific and not uniform, but is well modeled by IGRF and WMM. In many locations such as the North Atlantic, US West Coast, Australia etc. it comes in at around 10 nanoTesla per nautical mile. The accuracy limiting factor for a well calibrated tag is the amplitude of magnetic anomalies in the area. They can be quite extreme in areas such as the Galapagos rift zone or around Iceland, but are mostly more moderate. We have so far demonstrated 35 nautical miles average north-south accuracy across a dozen experiments or so, and that's a good rule of thumb number for accuracy by this method. We are working towards 10 nautical miles in some specialty cases, but this quickly gets quite complex.

Hi Matthias,

a bit late maybe, but still an answer to your question. The new generation miniPATs can be located in transmission mode through Argos messages and UHF pings. The latter can be activated in the new Tag Agent tool. You can set up there the use of an external release device that will leave the tags pin intact and thus allow you a redeployment of your tag.

Check page 11 in the new miniPAT manual (accessible through this link and attached to this message):

http://wildlifecomputers.com/wp-content/uploads/manuals/MiniPAT-User-Guide.pdf

For your sampling scheme a duty cycle setup might also be interesting (Page 13).

Cheers,

Robert