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Cyprinella hybrids?

Started by Guest_Uland_* , Jul 12 2011 09:01 AM

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11 replies to this topic

#1 Guest_Uland_*

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Posted 12 July 2011 - 09:01 AM

It's been far too long since I've posted and also far too long since I've been fishing!
Scott, Blake and I managed to get out over the weekend and photographed quite a few fish.
We found C. spiloptera and C. Lutrensis together. This particular location is usually has a C. lutrensis population that vastly outnumbers C. spiloptera (rarely see any spiloptera) but this day we found many and a few odd fish which I suspect might be hybrids.
I honestly don't see what I think might be hybrids often and wonder if in this case I'm being a bit sensitive and simply seeing atypical variation.

All below photos taken on the same day from the same river.

Posted Image

1 645.JPG 42.33KB 2 downloads

1 805.JPG 39.22KB 1 downloads

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#2 Guest_gerald_*

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Posted 12 July 2011 - 11:15 AM

I dunno whether those are hybrids, but it sure looks possible and C.lutrensis is notorius for hybridizing, especially where introduced into another Cyp's range. The USGS invasive aquatic species site has some info on lutrensis hybridization. I've seen what I think are hybrids with C.nivea and/or analostana in the Haw River and Yadkin River in NC where lutrensis is introduced.

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#3 Guest_jblaylock_*

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Posted 13 July 2011 - 05:15 PM

I'm no scientist...but the photo of the last fish sure looks like a hybrid. You can see it especially around the head/mouth area.

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#4 Guest_Skipjack_*

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Posted 13 July 2011 - 08:51 PM

Where did you catch it? Name it! Turd creek shiner.

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#5 Guest_rjmtx_*

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Posted 13 July 2011 - 09:19 PM

Were you downstream of effluent or in turbid/polluted water?

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#6 Guest_Uland_*

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Posted 13 July 2011 - 09:56 PM

Oh Matt! It's good to be back on the forum :tongue:

Gerald...Is it known why/how C. lutrensis so easily/readily hybridize and furthermore where introduced out of native range? Inquiring minds want to know!

Both C spiloptera and C. lutrensis are native to this river (Vermilion River Illinois River Drainage). Seems like north central Illinois is a battleground for the two as I don't think I've ever encountered a stream where the two were equally divided but my experience is limited....so many streams - such little time.

Robby, this river is pretty clean actually - well as far as northern Illinois is concerned but a cement plant is located upstream along with a low head dam....I have to check that dam out one of these days.

I guess I really don't know how to go about providing with any level of certainty you've found a hybrid minnow in the field. I see collection records regularly report "cyprinella hybrid" or some other genus and wonder how one can make such a determination in the field.

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#7 Guest_farmertodd_*

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Posted 14 July 2011 - 09:37 AM

I'm convinced.

The "pollution" can be as simple as homogenization. There is a good amount of literature on the effects of lutrensis introductions. I don't have citations on hand, but I did a quick look at Google Scholar and that will get you in business if interested.

Todd

Edited by farmertodd, 14 July 2011 - 09:38 AM.

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#8 Guest_gerald_*

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Posted 14 July 2011 - 10:04 AM

My off-the-cuff guess is that horny aggressive lutrensis males come charging in wherever they see something vaguely like Cyprinella spawning going on, ram the spawning male hard, then blast the crevice with sperm. They're about as choosy as toads in breeding season. (I've seen a toad mating with a spotted salamander egg mass). It may happen less with co-evolved Cyps in their native range, but it's still possible.

In NC none of our native Cyps have red on the sides or fins (execpt red tail on fieryblack) so when I see red where it shouldn't be and deep body shape, I assume lutrensis hybrid. I have never seen apparent hybrids of any of our native Cyps, but have seen several obvious hybrids of chub-nest spawners in other genera (Phoxinus x Clinostomus, Notropis chlorocephalus x Clinostomus, Luxilus x Nocomis).

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#9 Guest_travishaas_*

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Posted 14 July 2011 - 10:58 AM

Folks at USGS, Tulane and elsewhere have been poking their heads into red shiner hybridization. It seems that F1 hybrids are rare, but backcrosses (hybrids breeding with hybrids or "pure" individuals) are doing a fine enough job of mixing up the gene pool. Where red shiners have been introduced (usually via bait buckets), hybrids aren't uncommon. And as others have alluded to, turbidity is the nasty that is most commonly blamed for making hybridization common.

Travis

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#10 Guest_blakemarkwell_*

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Posted 14 July 2011 - 12:46 PM

Yeah, I'd bet you would get nuclear-mitochondrial discordance in those bottom two individuals! :rolleyes:

While C. lutrensis is introduced in many states, both C. lutrensis and C. spiloptera are native and largely sympatric in Illinois. I'm sure the postzygotic RIMs keeps large numbers of hybrids at bay in this population, but we sampled this section thoroughly so it is no surprise that a couple of putative hybrids showed up.

Additionally, this population is heavily skewed towards C. lutrensis. Any given day, you sample about 250-1000 C. lutrensis per 1 C. spiloptera. Therefore the rarer C. spiloptera eggs probably have a greater chance of running into the milt of heterspecifics (C. spilotpera) than conspecifics. The "pollution" would only exacerbate the poorly defined prezygotic RIMs (both crevice spawners during summer) among the Cyprinella.

Blake

Edited by blakemarkwell, 14 July 2011 - 12:48 PM.