Jump to content


Photo

Gravid Etheostoma collis


  • Please log in to reply
4 replies to this topic

#1 mattknepley

mattknepley
  • NANFA Member
  • Smack-dab between the Savannah and the Saluda.

Posted 22 January 2014 - 10:36 AM

One of the really neat things I've learned on the forum is that some Etheostomas can be identified as gravid not only by a swollen appearance, but also by a dark, curved area showing through their abdomens, visible from the bottom.

Attached File  SAM_1551.JPG   415.16KB   2 downloads

When I was out in the water yesterday, female Carolina darters (E. collis) were the most-often netted fish. Only one was starting to look plump, but the rest were beginning to show the "dark tummy" signs of being gravid. Is there any information on how long it takes an Etheostoma to reach spawning readiness from the outset of the visibility of eggs? I'm curious, as fish across varying parts of their range can spawn at different times based on their environmental cues (changes in daylight, water temps and levels, etc.). Is it likely my girls will be spawning earlier than in March, which is their normally identified season? Or do these black tracts in their gut take a couple months to fully develop? Just curious if anyone knows.
Matt Knepley
"No thanks, a third of a gopher would merely arouse my appetite..."

#2 Guest_gerald_*

Guest_gerald_*
  • Guests

Posted 22 January 2014 - 01:13 PM

What exactly IS the dark thing? If it's food in the intestine I don't see what that has to do with ovaries, other than maybe expanding ovaries pushing the intestine against the ventral body wall where it's easier to see it. Can't speak to E.collis specifically, but most fish collected in winter and brought indoors will spawn much quicker than they would if left out in the cold. I've seen Elassoma zonatum caught in mid-Feb spawn within 1-2 days after being brought inside to room-temp conditions (and fed blackworms).

#3 Guest_UncleWillie_*

Guest_UncleWillie_*
  • Guests

Posted 22 January 2014 - 01:26 PM

What exactly IS the dark thing? If it's food in the intestine I don't see what that has to do with ovaries, other than maybe expanding ovaries pushing the intestine against the ventral body wall where it's easier to see it.

The first thing I thought when I saw the photo (before reading the post) was that the dark line was intestines, too.

#4 mattknepley

mattknepley
  • NANFA Member
  • Smack-dab between the Savannah and the Saluda.

Posted 22 January 2014 - 01:46 PM

I can see where it would look like poop. Here's a link to a trip report of mine; there's a picture of a darter with some gill parasite issues I was asking about half way down the post. Dustin pointed out the poop looking stuff as a gravid indicator, but wasn't sure just how. He had hoped some biologists would chime in, as did I, but no luck.

http://forum.nanfa.o...erdam-creek-sc/
Matt Knepley
"No thanks, a third of a gopher would merely arouse my appetite..."

#5 Guest_gerald_*

Guest_gerald_*
  • Guests

Posted 22 January 2014 - 03:40 PM

Just a wild guess, but maybe the spleen darkens as it cranks up blood cell production to feed O2 to the growing ova ???




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users