NANFA-L-- Releasing native fish back to the wild -- EVER acceptable?

Jase Roberts (
Wed, 23 Aug 2006 12:57:42 -0400

Hi All,

First, I was glad to see a number of people jump in and correct the recent suggestion, "When your fish start to breed just throw them back in a lake or stream." IF any fish are EVER to be released back into the wild (see my question below), it certainly has to be done in a very thoughtful manner.

I'm sure the issues surrounding releasing native fish back to the wild (within their known ranges, of course) have been discussed to exhaustion. Several folks suggested searching the e-mail archives for the full discussion. I've done that for a number of questions in the past, but it takes a LOT of time. If you search the NANFA archives using Google, your results don't come up threaded or with a lot of meaningful context -- so it can often be very difficult to separate the serious discussion from casual references. You wind up with a lot of one-sentence messages where the hit is on terms contained in a message that has been replied to many times over. Also, discussion drifts to other topics, so the subject line isn't always a great indicator. Fully researching this question via the e-mail archives would take hours, I'm certain.

So... Has anyone ever pulled together a detailed compilation of the issues surrounding returning native fish to the wild -- including when it is and is not acceptable (if ever)? If so, where can it be found?

I did turn up this article from Bob Bock (past NANFA pres) (, where he notes:
"DON'T RELEASE ANY FISH INTO A DRAINAGE SYSTEM WHERE IT DIDN'T ORIGINATE. Even if the fish doesn't find another of its kind to reproduce with, it could still spread diseases or parasites. Similarly, if you're going to keep fish from a number of different places together in the same tank, you shouldn't release them back into the wild. If you can't keep them or find a good home for them, it's better to euthanize them."

My background is Conservation Biology, so I have a good handle on this stuff. My reaction to the releasing natives back to their home range would be similar to Bob's -- okay if it's the same body of water or directly-connected AND the fish have been kept separate from those from other areas. Others here seem to feel that once you bring them home, you NEVER release them, regardless of how they've been kept.

The issue of releasing/introducing fish outside of their native range is very easy to understand, and many, many examples can be cited. No one with any baseline understanding of ecology could possibly argue about that.

However, I'm fuzzier on the concept of spreading disease. If I'm collecting within a 50-mile radius of my home and keeping the fish communally (or with imperfect separation of water, equipment, etc), would it be acceptable to release fish back into local waters where I *know* they are native? What if I'm careful enough to track exact collection location and return them to the same exact same locations, so that I don't do any mixing of populations? If a fish has been healthy in an aquarium for 6 months and kept only with other fishes from the immediate area (but not same body of water), is there a real possibility of spreading disease back to the wild? With all the movement of waterfowl and boats, is it actually plausible that a bacteria or virus pathogen could be so localized that moving a fish from one pond to another 20 miles away is likely to cause a serious outbreak?

I'd love to hear some serious discussion -- or be pointed to references where this has already been debated to death.

Thanks much,

P.S. Anyone know the story on 2006 e-mail archives? I hope all this stuff is being saved somewhere...

Jase Roberts
Lewiston, Maine
on the Androscoggin River
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