[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Dealing with the real fish? problem
On Fri, 26 Jun 1998 peter.unmack at ASU_Edu wrote:
> On Thu, 25 Jun 1998, mcclurg luke e wrote:
> > Point of contention: no fish or animal is truly "native".
> You can define it anyway you like, but I defined it in my previous
> post, you are twisting my definition. _Most_ people agree that something
> moved by modern man is not native. Things moved by natural causes are native.
> One can argue that humans are natural too and that that makes translocations
> natural. I don't agree with that definition.
Our definitions differ then...that's all that can be said about it.
> > Populations rise and fall shift and change.
> > A fish is only native because man has documented it in that location.
> We can only go on what we record. If we base things on unrecorded events we
> achieve nothing. Do you have a better suggestion? If species are sufficently
> studied populations can usually be shown to vary genetically, hence additional
> new populations found can frequently be determined to be "native" or likely
> introduced based on unique genetic info.
> > What if we found a body of water after a
> > earthquake which allowed two watersheds to intermingle where before they
> > were separate?
> Then it is native. If a human carries it in a bucket between the same
> watersheds it is not native _by my definition_.
again...difference of opinion...irrecondcilable difference I'm afraid.
> > It DOES happen. My point here is that while it is
> > reasonable to say a South American Cichlid will not naturally invade the
> > Great Lakes. It is also NOT reasonable to say that a fish found in one
> > watershed cannnot colonize another...see below.
> I _never_ said it cannot. I work on biogeography, I am well aware of how
> natural events can shift fish around.
> > Very true. But would you agree that if you are keeping fish from a
> > specifici location and watershed that the diseases in your tank is the
> > disease that came from that same location? Exotic diseases are a problem
> > I understand that...don't get me wrong. I'm stressing the need to not
> > OVER-react to disease threats. Simple common sense will normally win the
> > day.
> What about the fish in the other tanks you have that aren't from that area?
> Do you ever use the same net in both tanks? Do you ever use the same syphon
> hose in both tanks? Do you ever thoroughly wash your hands between sticking
> them in seperate tanks?
> It's not a matter of over reacting. It is a matter of being responsible and
> making folks realise the risks posed. Sure, the chances are not that great.
> But lets say 1 in 1000 times something negative happened. How many releases
> occur in the USA a year? I have no clue, but I'll bet you it's in the
> thousands. How many diseases are we prepared to risk introducing? The chance
> is not that great but prevention is not that difficult or expensive either.
> > Kansas biology especially, I know the conditions of these watersheds
> > better than many outside the state. In short, they suck!
> So because the watersheds are in bad condition we shouldn't worry about it?
that was NOT my point...don't start taking things out of context. I meant
we have MORE to worry about than a stray bass or channel cat. For time's
sake I will leave it at that.
> > The fish I
> > transport are not from the Arkansas drainage to the Kansas drainage.
> > (perhaps I wasn't clear on that) They are from the Kansas drainage to
> > farm ponds whose run-off goes back INTO the Kansas drainage.
> The Arkensas drainage is huge! The Kansas is also not small. They are
> certainly bigger than the Gila drainage out here. You are ignoring potential
> microgeographic variation. In the Gila basin no two loach minnow or spikedace
> populations are completely alike.
My point...I'm not tallking about Spikedace or Loach Minnows. I'm talking
about gamefishes native to the area (or native NOW due to previous
introduction)...no NOT exotics either, but generally ALL gamefish are
introduced to some degree.
Yet, they only occur in one drainage. The
> whole idea is to be cautious. We don't know everything about the biology of
> these species and we probably never will. It is nieve to think two
> populations are alike just because they look the same to the naked eye. There
> are far more potential subtle differences that could be important that the
> naked eye cannot detect.
I think we give nature far too little credit. It is the height of man's
arrogance to think he can solve all the problems (even the ones he
creates) or understand all the nuiances of creation. Mutation,
introduction, colonization etc is natures way. Sometimes man speeds it
up...some times he slows it down. Fishes which have the chance to
colonize should be given that chance. That's my opinion...
> > Sport fishes
> > are raised by Wildlife and Parks officials in hatcheries around the state
> > from BOTH drainages and stocked in BOTH drainages. Whatever "killer
> > diseases" might have been lurking out there have LONG since been
> > intermingled.
ANd yet, if we go about nuking the species that they have introduced we
have just likely created an ENEMY and not an ally. In other words, lets
work within the system and try to be FLEXIBLE. Just as nature can be.
> That assumes more are not being added via aquarium releases. And also, just
> because the state does it doesn't make it right and it doesn't justify anyone
> else doing it.
> > NO the threat in this state is not from fish moved between
> > drainages...again see below for more...but from pesticides, feed lots, and
> > urban sprawl sucking the very life out of our rivers. Fishes in this area
> > tolerate disease much better than they do the other things.
> They are all threats. I've never said translocation is the only threat, nor
> the most important, just that it is a problem.
> > With all due respect...whose principles? I don't mean to be insulting,
> > but again, a muddy Kansas stream is far different than an Arizona spring.
> > I see both of our philosophies have strong points, but they also have
> > flaws. I think reasoning and WISE compromise solves more in the end than
> > a one person, or one blanket approach to the issues.
> Basic biological principles.
Basic biological principles change from textbook to textbook and classroom
Genetics, behaviour, ecology, evolution.
sorry, I'm a creationist and know evolution to be a farce. It's sciences
attempt to explain a creation without acknowledging it's Creator.
> can put two populations in different places, even if they are identical and
> they may gradually change and likely in different ways to each other.
> Species is a human concept that does not apply well to the natural world as
> things don't "fit" into boxes. All this means is there is a difference
> between what we see as a species and what "biology" (meaning things in the
> natural world) see as species.
> > It happens all the time here. We have a wonderful bird called the Great
> > Blue Heron that doesn't recognize boundaries OR watersheds. They have
> > "stocked" fish in waters that had none before. In our own family farm
> > pond we had Green Sunfish AND Pumpkinseeds appear without any human help.
> > NO, someone did not place them there, some BIRD did. I have personally
> > witnessed Herons open their mouths to take a fish only to have several
> > small ones drop into the water its fishing.
> I don't agree with your observations above. Just 'cause you saw a heron drop
> fish when it was fishing for others doesn't mean anything concrete. How do
> you know it didn't just catch them and it only had them in it's mouth for a
> very short period of time. How long is a heron likely to carry a live fish
> around before eating it? I doubt it would be that incredibly far. Also,
> these type of habitats _usually_ occur at lower elevations within drainages.
> Hence, a bird is more likely to go to the next likely waterhole in the same
> valley. Why fly over a mountain, carrying water and fish when the next
> nearest fish population is likely not that far away in the same valley? Sure,
> that will not _always_ be the case, but in most cases it will be. Surely too
> once it is in it's gut it is dead right. How do you know the next farm
> upstream of your pond doesn't have sunfish in their pond, or the farm above
> them? Fish are amazing creature, you'd be surprised where they can get to
> during extreme rainfall events. You don't need to have a significant
> watercouse for them to migrate.
then come to Kansas and study the situation yourself. I take you word on
the Arizona situation because you are there. Why are my observations and
the observations of several genertions of country people to be dismissed?
Because some book says so? that's a little arrogant to me. As for high
water levels, I saw this same pond (which has an outlet that runs through
a tube that is roughly ten feet above it't discharge pool in the 500 year
flood of '93. Even at that high water mark, the discharge stream was
still a verticle drop of 5 feet or morel. I don't know any pumpkinseed or
green sunfish that could swim that. let alone enough to establish a
breedihng population. Heron, pelican and others DO move fish. It's been
seen and documented and is a well known fact here. Believe me or
not...end of discussion.
> Also, no one, ever, has demonstrated that a bird successfully transported
> fish, let alone one that started a new population.
so because a research scientist hasn't proven it, it's not so huh? Don't
make the mistake of thinking science can prove everything...it leads to
> Furthermore, I'd refer you to Cross, Mayden, and Stewart, Fishes in the
> western Mississippi Basin. In, Zoogeography of North American Freshwater
> Fishes. pp 363-411. In this paper they look at faunal similarity amongst
> many drainages including the Arkansas and Kansas Rivers. They have a table on
> page 398 showing the % faunal similarity between rivers in their study area.
> The Kansas and various parts of the Arkansas have between 53-65% similiarity.
> Within the Arkansas drainage the lower river and middle river are similar by
> 80%, the middle and the upper are similar by 74%. If birds shifted fish with
> any degree of regularity wouldn't you predict that the levels of faunal
> similarity would be higher--expecially between the two major drainages?
Not necessarily, due to different habitat conditions. Did you ever think
that the similiarities could be aided by the very think you're trying to
> many of these will be habitat specialists, however, there are many native
> species that are not shared by both drainages--especially cyprinids which are
> typically mid water species making them more vulnerable to birds like herons
wonderful word "presumably". throws a lot of doubt on to the subject. :)
> > How do you suppose some of
> > these species got so widely distributed in the first place?
> They swim. Virtually all exceptionally widespread species are very tolerant
> of a wide range of environmental conditions, ie they are very adaptable to
> adverse conditions. Hence they are good survivors in a ranage of habitats
> which makes them more likely to persist and spread.
> > you suggest it... we do not live within miles of any creek that carries
> > the two species and there are enough high obstacles (small waterfalls
> > mainly) to prevent invasion. It's possible, but not the only possibility.
> > Also, don't forget about snapping turtles, beavers, waterfowl, etc. who
> > all don't recognize watershed boundaries but travel where and when they
> > please. It's too easy to get panicked about introductions and disease.
> > The point is, it happens regardless of man's participation.
> But, do you agree that humans increase that risk?
No doubt at all. Before we condemn the transportation of species in their
ranges though, let's get rid of the exotics (yes, our definition does vary
on that) Establishing ONE RULE for all watersheds WILL NOT WORK! PERIOD.
That is the crux of this discussion and on this I don't think our own
opinions will change.
I'm not trying to create
> panic, just awareness.
> > Exotics verses introduced natives is a difficult discussion.
> How do _you_ define exotic and introduced?
In Kansas, the Wildlife and parks people stock Rainbow trout in several
lakes. They do not survive on their own except in extreme S.E. Kansas on
the Ozark Plateau. They do not normally survive the winter. It is an
obsecene waste of money and time to produce an artificial fishery for
trout. Perhaps not so with stripers, walleye, sauger or other
fishesintroduced into impoundments that fill a biological niche created in
impoundments. These fishes (or some of them) were not present in Kansas
waters before but now serve a viable as I understand your definition, you
would remove these fish. I wouldn't. They are not "natives" but they are
native to the region (on a broad scale) Oscars, angelfish, and platys are
NOT native on any regional scale and would be exotics. Sorry, not too
much time to explain further...
> > I hope I haven't offended anyone.
> Not me anyway. :-)
> > In the same light, I tend to get a little punchy when someone
> > from another part of the country starts telling me what I need to do in my
> > own backyard, when I know darn well that person may not have all the
> > information I have on the subject.
> Likewise, I tend to get emotional when folks ignore principles that are mostly
> independant of geography. :-)
> I'm glad you've kept the questions and arguments coming.
For now, I've said all I care to. Our opinions are different...but I
think there is room for both.
> Peter Unmack