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#1 Guest_beanosvaughn_*

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Posted 04 June 2011 - 06:00 PM

I will have the opportunity to do some sampling in hawaii next week. There are many rocky tidepools with various species of saltwater fish like eels,blennies,and gobies. There is also the Wailua river which contains barracuda and even the occasional shark as well as other interesting freshwater species. I am so excited! :mrgreen: Are hawaiian fish considered north american natives?

Edited by beanosvaughn, 04 June 2011 - 06:01 PM.


#2 Guest_EricaWieser_*

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Posted 04 June 2011 - 06:26 PM

Here is a list of the freshwater fish of Hawaii: http://fish.mongabay...data/Hawaii.htm

They're mostly gobies, which is to be expected of an island. Gobies are capable of living in both salt and freshwater, so they are excellent colonizers of the freshwater streams of volcanic islands. Personally, I admire gobies for their adaptability, and I think they're cute. But although some species may physically resemble darters, they're not closely related. Gobies have fused pelvic fins that mimic the action of a suction cup to keep them attached to what's under them, which darters don't. Here's a picture of that fused pelvic fin: http://2.bp.blogspot...Sirajo goby.jpg
and another: http://farm3.static...._fed2467186.jpg

Politically, Hawaii is part of the USA, but the flora and fauna are quite different from that found on the continental United States.

Edited by EricaWieser, 04 June 2011 - 06:35 PM.


#3 Michael Wolfe

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Posted 04 June 2011 - 06:56 PM

I will have the opportunity to do some sampling in hawaii next week. There are many rocky tidepools with various species of saltwater fish like eels,blennies,and gobies. There is also the Wailua river which contains barracuda and even the occasional shark as well as other interesting freshwater species. I am so excited! :mrgreen: Are hawaiian fish considered north american natives?


The geobiology answer is no...

... and yes, I am just making up words.
Either write something worth reading or do something worth writing. - Benjamin Franklin

#4 Guest_fundulus_*

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Posted 04 June 2011 - 08:35 PM

Biogeography works better. And I think in the past we've decided to treat Hawaiian fishes as North American, partially because of political boundaries, partially because Hawaii is out in the middle of nowhere in terms of continental affiliations, and partially because the fish are interesting.

#5 Guest_beanosvaughn_*

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Posted 04 June 2011 - 09:26 PM

up]Thanks for the replies everyone! I got a new underwater digital camera so I will be able to take video and pics. I am not sure how much freshwater sampling I will be able to do but I will be exploring rocky tide pools almost every day.I do hope to try and fish the river I mentioned earlier though. I didn't know Hawaii had such an intereting variety of freshwater fish!

#6 Guest_rickwrench_*

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Posted 04 June 2011 - 10:58 PM

Most of the creeks are infested with tilapia, apparently one of the more salt water tolerant species as they've colonized all the creeks. One place to see an example of this is a small irrigation canal that runs between the Foodland and Safeway supermarkets in Kapaa. There is a walking bridge over the canal, between the two parking lots. The canal is absolutely packed, with thousands of large tilapia.
I've never had a chance to i.d. the species.


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#7 Guest_beanosvaughn_*

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Posted 05 June 2011 - 01:50 PM

Cool! Are they native or introduced?

Edited by beanosvaughn, 05 June 2011 - 01:56 PM.


#8 Guest_fundulus_*

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Posted 05 June 2011 - 02:19 PM

Introduced, no native cichlids in Hawaii.

#9 Guest_beanosvaughn_*

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Posted 06 June 2011 - 07:56 PM

I will apparently be passing through kappa on our way to a tourist attraction.I convinced my mom that it would be cool to stop at the irrigation canal and see a fish introduced from Africa(correct?)I might even be able to do some angling.

#10 Guest_rickwrench_*

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Posted 07 June 2011 - 05:52 PM

Here's the google maps link:

http://maps.google.c...&z=18&t=h&hl=en

The walking bridge over the canal is right behind the Pizza Hut.

I took a quick shot down into the (freshwater) canal from the walking bridge last time I was there. No polarized filter on the cheapo Canon point and shoot, so there is some glare. But you can still make out the mass of fish.
That's a LOT of tilapia:
Posted Image

They are in most of the east side (saltwater) tidepools as well. Here's a shot of a bunch hanging out with some Hawaiian Sergeant Majors.
Posted Image

Closer:
Posted Image

Never got one in hand to id. Although I think I can generalize with the word "invasive scourge". I'd heard they were originally introduced to control weeds in the sugarcane irrigation canals, then were supplemented by aquarium releases.
Nobody on Kauai seems in much of a hurry to officially identify them, find out what kind of havoc they have wrought on the inshore ecosystem. Nobody on Kauai seems in much of a hurry to do -anything-, in fact.

Rick

#11 Guest_EricaWieser_*

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Posted 07 June 2011 - 08:53 PM

Never got one in hand to id. Although I think I can generalize with the word "invasive scourge". I'd heard they were originally introduced to control weeds in the sugarcane irrigation canals, then were supplemented by aquarium releases.
Nobody on Kauai seems in much of a hurry to officially identify them, find out what kind of havoc they have wrought on the inshore ecosystem. Nobody on Kauai seems in much of a hurry to do -anything-, in fact.

I know it's easy to hate on invasive species and to say how awful they are, but you have to keep in mind that the Hawaiin ecosystem itself is relatively young, and even the fish "native" to it (check this list: http://fish.mongabay...data/Hawaii.htm ) are infiltrators from their previous, saltwater home.

List of native species:
Awaous guamensis ( a goby, a saltwater invader), Eleotris sandwicensis (an extremely aggressive fish that eats anything that will fit in its mouth), Kuhlia xenura (another saltwater invader), Lentipes concolor (another goby saltwater invader), Mugil cephalus (saltwater again), Sicyopterus stimpsoni (goby), and Stenogobius hawaiiensis (goby).

So to really hate on the invasive species you have to hate on every species of fish found in Hawaii, since Hawaii hasn't existed as long as the continental United States, where we have species that are truly freshwater only.

Edited by EricaWieser, 07 June 2011 - 08:54 PM.


#12 Guest_fundulus_*

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Posted 07 June 2011 - 09:04 PM

Conversely, we as humans have contributed to wiping out much of the biota over the past 1000 years. So now Hawaii can receive its fair share of cosmopolitan species like Tilapia, and probably gray squirrels by now.

#13 Guest_rickwrench_*

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Posted 08 June 2011 - 12:08 AM

I know it's easy to hate on invasive species and to say how awful they are, but you have to keep in mind that the Hawaiin ecosystem itself is relatively young,


Compared to... ?
Only 18k years ago, Michigan was under a mile of ice. The Great Lakes ecosystem, as we know it, is less than 15k years old. Should we keep that in mind as bighead carp take over that relatively young ecosystem?
As in Hawaii, some N.A. freshwater fish species we know today evolved from saltwater ancestor "invaders". Some are still diadromous (sticklebacks), though some are also now purely freshwater. Hey! Tule perch for example.

Kauai is the oldest major island in the chain, with no volcanic activity in 400k years. Other than sea level changes, I'd imagine Kauai, in the central Pacific, to be one of the more stable ecosystems during the last 100k years of ice age. And completely isolated. Any native freshwater fish there would have evolved with either zero or very minimal competition as they moved into an empty, unexploited environment. They would have no chance competing with suddenly introduced tilapia.

Of course, eventually, stability will be reached. In Hawaii, in the Great Lakes, in the Sacramento/San Joaquin delta.

Rick



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