Native fish

Nathan,

Regarding Atlantic Salmon extinction...

I actually think this is not entirely true. My memory of recent reports is that the stocks of Atlantic Salmon in the northern part of their range are doing OK. This would mean that the species is not in danger of extinction, but perhaps local populations (i.e., in the northern US) are at risk of extirpation. This is a big difference. There may be many reasons for a species to go extinct. In addition to the numerous anthropogenic sources of stress for the salmon, I think one non-anthropogenic reason for Atlantic Salmon problems in the US is climate. Closer to the last ice age the waters (riverine and oceanic) of the northeast US were more to the salmon's liking than now (mostly - cooler). Even if we stopped all fishing, for example, the US stocks would still be under incredible stress from climate change.

just my $.02.

Aaron

Here it comes....

OK, I can't let this one slide by without pitching in my .02... We have hammered fish populations by overfishing in many cases throughout history, but we have never fished a species to extinction. This is not to say over-fishing is right, it's just to say that to make a species extinct it takes destruction of habitat. Over-fishing is definitely WRONG.

Over-fishing destroyed the striper population in the northeast despite open reign of coastal waters to hide in. Regulations brought them back. Clearly it has an impact. But we (thankfully) try as we might could not fish them into extinction.

Extinction, on the other hand, has occurred in many salmon runs. Build a dam without passage and BINGO. Gone. No habitat to procreate - no offspring - no future - no fish.

Sure, they are clever and will seek other rivers in the immediate system or general region, but they will not wander far from their natal stream because they are driven to it from thousands of miles away. The northeast does not offer many alternatives to save a run. If we dam the Merrimac, once a natural salmon factory, they will not divert to the Connecticut (even if it weren't dammed up itself).

The Saco, such a fine freestone stream, a river I would dream of fishing for it's native atlantics on - went extinct with the first dam. Up and down the Maine coast, entire races eliminated by habitat loss.

On the other coast, the Elwha and it's race of hundred pound class king salmon, as big as the Kenai in Alaska - extinct. Races of steelhead all over the northwest have been eliminated and many partially replaced with introduced hatchery stocks. It's hard to tell whether an unmarked streamborn fish is of native stock anymore due to interbreeding during certain times of the year. The native fish have been selectively bred (by harvest and seasonal regulation) to be a spring steelhead, in other words you can keep anything up until a certain date; and they introduced early return hatchery fish to meet quotas. Now the native fish are a spring fish as a result.

I have not heard anything about climate persistently affecting a race of fish, although I am certain that cyclic patterns do have an impact. Even then nature provides jacks (prococious young salmon) who can breed in the tiniest trickles to keep things alive through it's diversity.

There is a Jacques Cousteau episode where they found a geothermal spring melting a glacier. The spring would poach a salmon, the glacier would freeze it. In the neutral zone, the water was perfect for hatching eggs, so the salmon dug redds there under the ice and reproduced. It was one of the most profound things I had ever seen about salmon.

The climate is an interesting theory but I have a hard time accepting that it is a factor in the reduction of fish populations or else it would affect every region to varying degrees. Aaron - canyou point me to any substantiating information on this?

Now what on earth could be changing the <i>climate</i>?

Juro et al.,

The impact of climate change (warming) on ecosystems worldwide has been a topic of intense focus within various biological disciplines for a while. That climate change will impact ecosystems as we know them is a given. How those ecosystems (and the species in them) will respond is another issue altogether. Even in the field in which I work (coral reef ecology), the 'bioregion' that is expected to get the least amount of temperature increase (relative to more polar climes), evidence is mounting that very major problems associated with climate change are occurring.

this points out a major problem with the scientific community - there is an incredible lack of communication with the rest of the world. Scientists, in general, are terrible at presenting their findings to everyone else. And, unfortunately, the general media aren't sophistacted enough to explain it - especially when an issue is complex as the effects of limate change.


But to get to the salmon issue:
Nathan - in light of the fact that the current rate of climate change might be considered 'catastrophic' in evolutionary and ecological terms - on temporal and spatial scales - I doubt the ability of salmon to adapt. Anthropogenic changes are happening way too fast for most species to adapt, and are closer to past (geological time scale) catastrophic changes associated with mass extinction events.

Juro - lots of information out there. I did a quick search on a bio search engine and came up with the papers listed below. that's doesn't even scratch the surface. realize, most (all?) of these studies were funded by competitive grants, so climate has to be enough of an issue to get funding.

Empirical Links between Thermal Habitat, Fish Growth, and Climate Change.
Author(s)
King, J.R.
Shuter, B.J.
Zimmerman, A.P.
Journal Info
Transactions of the American Fisheries Society
JUL 01 1999 v 128 n 4
P. 656

Modeling of Climate Change Effects on Stream Temperatures and Fish Habitats Below
Dams and Near Groundwater Inputs.
Author(s)
Sinokrot, B.A.
Stefan, H.G.
Eaton, J.G.
Journal Info
Climatic change.
JUN 01 1995 v 30 n 2
P. 181

Climate Change and Marine Fish Distributions: Forecasting from Historical Analogy.
Author(s)
Murawski, S.A.
Journal Info
Transactions of the American Fisheries Society
SEP 01 1993 v 122 n 5
P. 647

Global Climate Change and Fish and Fisheries: What might Happen in a temperate
Oceanic Archipelago Like New Zealand?
Author(s)
McDowall, R. M.
Journal Info
GeoJournal.
SEP 01 1992 v 28 n 1
P.29

Pacific Salmon Fisheries: Climate Information and Adaptation in a Conflict-Ridden
Context.
Author(s)
Miller, Kathleen A.
Journal Info
Climatic change.
APR 01 2000 v 45 n 1
p.37

Land use, fishing, climate change, and the decline of Thompson River, British Columbia,
coho salmon.
Author(s)
Bradford, Michael J.
Irvine, James R.
Journal Info
Canadian journal of fisheries and aquatic scienc
JAN 01 2000 v 57 n 1
p.13

Potential effects of climate change on marine growth and survival of Fraser River sockeye
salmon.
Author(s)
Hinch, Scott G.
Healey, Michael C.
Juanes, Francis
Journal Info
Canadian journal of fisheries and aquatic scienc
DEC 01 1995 v 52 n 12
p.2651

Valuing Effects of Climate Change and Fishery Enhancement on Chinook Salmon.
Author(s)
Anderson, David M.
Shankle, Steven A.
Scott, Michael J.
Journal Info
Contemporary policy issues.
OCT 01 1993 v 11 n 4
p.82

Probable Consewuences of Climate Change on Freshwater Production of Adams River
Sockeye Salmon (Oncorhynchus nerka).
Author(s)
Henderson, M. A.
Levy, D. A.
Stockner, J. S.
Journal Info
GeoJournal.
SEP 01 1992 v 28 n 1
p.51

Aaron

Great stuff Aaron, thanks. I will definitely snoop around.

I guess the point of the debate is not whether climate is a factor, but how impact of climate change rates vs. habitat loss and harvest. It wasn't hard to construe your initial point as if it were positioning harvest/habitat as having less impact, thus the reactions.

Harvest is without doubt a factor as shown by Orri Vigfussen's (sp?) buy out of the Greenland commercial atlantic fishery and it's profound impact on returns all over the north atlantic.

I agree that climate is also a factor, but without reviewing further evidence not as much of a factor as habitat and harvest in my (admittedly anecdotal) opinion.

Thanks for the refs, I will read.

Juro

<font size="1">[since I was typing under pressure (read: "come on dear, the kids are waiting to go get our tree") I modified my post to reflect more clearly what I was thinking]</font><!--1-->

Juro,

I guess the misunderstanding here is that I consider cliamte change to be a type of habitat change. The climate is just as much a factor for a species as river water quality, dams, etc. The frustration is that since climate change (or even many types of pollution) is so long term, has such a lag time (that is, the effects of what happens now aren't realized for many years), and thus is difficult to pin down as a direct cause and effect, it is often not seen as as large a problem as more 'immediate issues (e.g., dams). The thing is, dams effect only part of the 'habitat', so provide only part of the answer (albeit the most immediate one). I guess my biggest motivation in throwing my $.02 on discussions like this is to get folks to think about all of this with a much, much broader perspective.

RE: reading - there's plenty more if/when you get through this stuff... UMassBoston has a big library<g>.

Aaron

On the topic of carbonic and nitric increase in the atmosphere, I'm surprised no one has mentioned acid rain. I'm sure it hasn't gotten any better yet you don't hear much about it anymore. Entire lake systems in Upper State NY were lessened to a near sterile state due to extreme acidity from precipitation and runoff, directly related to carbon and nitrogen in the air.

This is what I might refer to as an "active" threat as opposed to the climatic change being what I might refer to as "passive" - like the ice age for instance, but no less a threat. (overt/covert? physical/metaphysical? direct/indirect?).

I guess when I refer to "habitat" I am talking about "active" threats like dams, agricultural runoff, effluents, erosion, etc. I would tend to call atmospheric and climatic impacts "environmental threats". The point is, you can take down a dam and the next pod will swim to the headwaters. You can prevent riparian zone logging and the eggs will not sufficate. If you correct the temperature gradient deviations, the salmon will still not reach the headwaters.

.02

Juro

Wow.. Global Warming. What can puny citizens do? All this talk comes down to local politics. If you talk about global warming as a local (or national) pol you are percieved to be a kook (ie. Al Gore). There are many conservative elements in this country that think Global Warming has not been proven to be man made. My opinion is that if it's evan a possibility we should throw more national resources at it..ya that means some of your tax dollars. It's a tough sell. The sad part is we can't evan get our own DMF to properly represent us regarding the Striper keeper lengths. How can we possibly affect change on global warming? I guess voting based on these issues is one way. But then you have to go against lower taxes and gun owner rights. What's it gonna be for you? What are your priorities? I personally like the very realistic goal of us showing up at the DMF meetings as mentioned in the other thread here. A quick simple way to make yourself count.

Terry