Each year more and more starving sea lion pups seem to be comming ashore. They are usually brought into rehab nursed back to health and released. Are we damaging the gene pool by rescuing these animals. They are cute as a button and irresistable but I have to wonder if we are hurting or helping in the long run.
Maybe a little…but only a little.
Consider how many of the “best” seal pups – the ones with the best health, the strongest immune systems, the apex of vigor – get eaten by orcas. That does a lot more harm to the gene pool than we will ever do.
So, yeah, we may be preserving some suboptimal DNA, but at so very small a level – something that just disappears under the horizon of ordinary variance – that it doesn’t matter a hang.
It makes us feel good, but doesn’t really change the world.
Depends what we are rescuing them from. The problem is that it is unclear how much of this is “natural” or anthropogenic in cause.
If it is say an autoimmune disorder caused by environmental pollution of some sort, then rescuers might be doing the proper thing. If for example older, more robust individuals can fight off the effects of the disorder but youngsters can’t, we might damage future breeding viability of the species if we did nothing.
On the other hand maybe it is just natural population cycling with prey species in which case we may be doing them no favors.
But in the long run I doubt it is having a dramatic effect one way or another.
I did a stint of volunteering at a marine mammal rehab place, many years ago. This question commonly was asked.
The standard answer (which, frankly, I thought was a bit lame) seemed to be: That this helps preserve diversity in the gene pool. After all, a diverse gene pool will enable the species to survive even when environmental conditions change. And who knows, the gene we preserve when we save that sick seal may be just the gene needed to help the species get along sometime in the future when conditions are a little different.
I’ve done some volunteering at the Marine Mammal Center in Sausalito, and my brother is a regular volunteer there. As I remember, the rescue animals there fell into several categories:
- Sickened by algae blooms caused by fertilizer runoff
- Hit by boats or shot by people in boats who liked to shoot things
- “Rescued” by misguided do-gooders who mistook a pup alone to be a pup abandoned
None of those things are really genetic weaknesses.
Seem to, or actually are?
And if they are, is it because we’re hurting them or because we’re not hunting them and there are just a lot more of them?
Starvation seems to be the main culprit. The populations have increased dramaticaly from 20 years ago, not sure how stable they are now.
Lot a sea lions with various other diseases too. Erysipelas was very common, rising to epidemic proportions in some years.
Some animals could never be released. So the same question was asked about them: What is the point in taking care of them and keeping them alive? The genetic question was meaningless, since they would never be released.
We had a male adult California sea lion named Zonker, who was epileptic. One of the volunteers was a nurse at a hospital, and somehow got a deal where they gave her all the leftover expired dilantin. So this sea lion lived in a tank and we gave him dilantin pills. He was there for years. Eventually he got placed at a children’s zoo, where he soon had a seizure and drowned.
It’s seem to, probably because of all the press during the 2013 sea lion Unusual Mortality Event when strandings rocketed to about five times their normal average. The overall number of strandings actually seemed to be going down from 2008 until last year.
A nice graph here
http://www.nmfs.noaa.gov/pr/health/mmume/californiasealions2013.htm
And that was the first UME for sea lions in about 11 years.
http://www.nmfs.noaa.gov/pr/health/mmume/
I don’t know what the numbers are this year, but I haven’t heard anything like it was last year.
That was an interesting graph, i guess it just seemed like they were going up.