If a buck is found dead in a pond.... appears to have been there 2+ weeks, and a lease member wants to take it to a taxidermist and get a euro does he have to tag the buck?

no

The taxi is gonna want a license number at a minimum. I would contact GW, tell the story, they may have a tag to give that allows the hunter to not burn a tag.

good advice

Do the euro yourself and save him some $. We have a cage that we put our heads in so nothing runs off with it. After the bugs have done their part, we soak it in water to let the water bugs do their part. Dawn soak after that, then beautician grade Hydrogen peroxide.

I would contact the game warden as well.

If the taxi gets checked the GW will want to know who killed the deer, when, where, etc. It will then fall on who brought the skull/antlers to the taxi for proof. Just because you say the deer was found dead, does not mean the GW will not get more involved when it was not tagged.

Yes you need to tag the deer. Just like finding a deer dead on the side of the hwy. I would contact the local GW

To clarify a dead deer on the side of the road, per TPW;

Q1: A deer has been hit on the highway, what do I do?
A1: If the deer is just injured call your local game warden dispatcher. If you are absolutely sure the deer is dead, you may move it off the roadway and leave it there. Texas Department of Transportation will remove the dead animal. It is illegal to tag the deer (or any game animal for that matter) and take it with you.

I bet that smell great. I would boil it myself.

Taxidermist might request a wildlife resource document to be attached ??

It’s in a POND, not on a ROAD

Yep.
And...it's basically no different than finding sheds or a skull. There was not any direct hunter involvement and no meat resource to preserve or utilize. Taking it to a Taxi is where the trouble will begin though. IF the Taxi or a GW either one choose to 'question' the possession..it might not be worth the trouble. Just do the Euro yourself, they are simple (but time consuming).

X2

100% wrong answer
I have 2 or 3 euro mounts that are bucks I found dead. Some were down to the bone, others still had hide on them.....talked to GW and he said I could legally take them home without tagging or notifications to GW.

I've heard it said many times that wounded deer often run to water.

Fully aware the OP said in a pond. However the comment I quoted said "Just like finding a deer dead on the side of the hwy." I was addressing that, as the two, road vs pond, are not the same situations and I believe its important to differentiate between the two. If I find a deer dead in my pasture or in a pond, I would assume I can do with it as I please. However, that is not the case for a deer on the side of the road. Its technically property of the state.

Well technically all deer are property of the state whether they die on you property or the roadside.

I think the big difference is you can take a deer and bury a body and take the antlers and do what you want with them if its found on your property a lot easier than if it isn't.

My point was the taxidermist will likely want a tag or license number or something to verify he isn't dealing with a poached deer. If you plan to euro the deer yourself, I don't think you need to tag the deer at all. If you plan to take it somewhere, you might want to at least verify with someone in charge a GW won't be making a stop at your house because you were transporting a "poached" deer.