Identifying Sex of Gars - Spotted Gar Dissections Part I

[E_americanus]

Hi All,

We wrapped up our spotted gar dissections yesterday and were able to shoot some video as well (did our best with the field camera, but we were able to record in HD). I realize most video goes in the media lounge, but I felt this is useful as reference material and also to generate discussion on the topic (so mods, please do not move).

In the video (unfortunately the intro clip was lost due to data malfunction) we first dissect a larger spotted gar specimen followed by a smaller specimen (you will be able to see both male and female examples). Note the differences in structure of the gonads, and how we use the gamete release pathways as a check on sex ID.

Feel free to comment or ask questions, hope you find the video informative--
--solomon

PS-- Richard was involved with collecting these fish from the field in 2010, my friend Jeremy (Eastern Michigan University) worked on the dissections and shot the video.

[YT]pBLK9Mtl29A[/YT]

 

[Wiggles92]

Great video, Solomon; I found it to be very informational. I look forward to any further gar dissection videos that you may post.

 

[E_americanus]

Great video, Solomon; I found it to be very informational. I look forward to any further gar dissection videos that you may post.

thanks Ryan, we have a few other vids from that day that i am still going to string together. now that i've started to experiment more with the movie-maker we'll hopefully be converting some other footage (hopefully field stuff) soon too--
--solomon

 

[sbuse]

nice in depth info on the fish. the noticly larger teeth on the wild adults make me want to catch some larger wild fish for the future gar tank. in addition to the yoy i will be looking for this summer. i wonder if the teeth they loose and regrow would be the larger or smaller style after it was in a tank for a while?

 

[E_americanus]

nice in depth info on the fish. the noticly larger teeth on the wild adults make me want to catch some larger wild fish for the future gar tank. in addition to the yoy i will be looking for this summer. i wonder if the teeth they loose and regrow would be the larger or smaller style after it was in a tank for a while?

thanks for the comments, we are glad to share this info and have a lot more to add in the near future.

the teeth seem to regress in captivity as this seems to be a pretty plastic trait. it's crazy because we can compare wild fish to the captive fish of similar size and the difference in tooth size is astoundingly obvious. it makes sense though, if you don't need the big teeth for hunting down prey, why put resources toward that trait? YOY fish raised in captivity and YOY wild fish raised in captivity seem to have the same smaller teeth issue; we're really primarily seeing the big teeth in wild specimens. this seems to be the case with all the US gars and tropicals, but since i haven't seen a wild Cuban we can only assume the same holds true.--
--solomon

 

[sbuse]

thanks for the comments, we are glad to share this info and have a lot more to add in the near future.

the teeth seem to regress in captivity as this seems to be a pretty plastic trait. it's crazy because we can compare wild fish to the captive fish of similar size and the difference in tooth size is astoundingly obvious. it makes sense though, if you don't need the big teeth for hunting down prey, why put resources toward that trait? YOY fish raised in captivity and YOY wild fish raised in captivity seem to have the same smaller teeth issue; we're really primarily seeing the big teeth in wild specimens. this seems to be the case with all the US gars and tropicals, but since i haven't seen a wild Cuban we can only assume the same holds true.--
--solomon

makes sence.

just a thought, if you were to raise a captive gar on a diet of strickly live foods of different sp, like perch, sunfish, minnows ect(all of these fish are in my fishes diet, just as a treat/ verioty, it mostly gets shrimp,fillets and pellets so it has the teeth to match the diet).

by doing that, could we see a 'large toothed fish' in the captive environment due to the fact that it would still have to work for its meals? or is it more of the fact that they don't have to ensure that their meal doesn't get away since it can only go so far, were as a wild fish has to keep its meal in contact at all times cause it may not get another one/chance at it?

one example is, if i were to catch a 2' longnose for my tank and feed it only live, could it maintain the larger teeth?

 

[E_americanus]

makes sence.

just a thought, if you were to raise a captive gar on a diet of strickly live foods of different sp, like perch, sunfish, minnows ect(all of these fish are in my fishes diet, just as a treat/ verioty, it mostly gets shrimp,fillets and pellets so it has the teeth to match the diet).

by doing that, could we see a 'large toothed fish' in the captive environment due to the fact that it would still have to work for its meals? or is it more of the fact that they don't have to ensure that their meal doesn't get away since it can only go so far, were as a wild fish has to keep its meal in contact at all times cause it may not get another one/chance at it?

one example is, if i were to catch a 2' longnose for my tank and feed it only live, could it maintain the larger teeth?

good question, i was going to comment on that earlier but never got around to it, especially since a lot of people would likely ask that in justification of live foods, etc. live foods alone don't seem to lead to the larger teeth issue, it is likely tied to other factors such as what you mentioned about the wild fish really having to track down their prey and make sure they don't escape. in captivity, even live food doesn't have many places to go/hide, so it's not the same as a wild environment (as we all comment in many cases). we raised all the SPGs in our experiments on live food from the larval stages to 2 years and we still don't see the larger teeth as in wild individuals of same size/age.

if you were to catch a larger wild fish, it will likely retain the larger teeth for a bit longer if you keep up the live food, but again, this is a very plastic trait, and i would expect the teeth to regress pretty quickly, perhaps within less than a year depending on the size/age of the fish.--
--solomon

PS-- those wild SPGs really have sharp teeth that don't just cut in a conical plane, but can cut like blades back and forth in many cases (getting tagged by a wild fish is much worse than a captive fish)!

 

[sbuse]

good question, i was going to comment on that earlier but never got around to it, especially since a lot of people would likely ask that in justification of live foods, etc. live foods alone don't seem to lead to the larger teeth issue, it is likely tied to other factors such as what you mentioned about the wild fish really having to track down their prey and make sure they don't escape. in captivity, even live food doesn't have many places to go/hide, so it's not the same as a wild environment (as we all comment in many cases). we raised all the SPGs in our experiments on live food from the larval stages to 2 years and we still don't see the larger teeth as in wild individuals of same size/age.

if you were to catch a larger wild fish, it will likely retain the larger teeth for a bit longer if you keep up the live food, but again, this is a very plastic trait, and i would expect the teeth to regress pretty quickly, perhaps within less than a year depending on the size/age of the fish.--
--solomon

PS-- those wild SPGs really have sharp teeth that don't just cut in a conical plane, but can cut like blades back and forth in many cases (getting tagged by a wild fish is much worse than a captive fish)!

thanx for the info.

this has me wondering if this teeth trait is also common in other fish. like bowfins for example. i have not raised on yet, but that will change if i time the spawn out right this year. i made the mistake of liping the first one i caught like a bass, bad idea. they have some narly chompers, but i wonder if it would be a simmilar situation with their teeth to the gars?

i know all to well about the wild bite vs the captive bite. my big florida has got me a few times while hand feeding. i was helping someone land a larger longnose on the st. crouix and it got my fingers/hand pritty good, much worse then my fl could ever do. never got to see that fish well/long cause that was the first pass and the guy saw me bleeding and cut his line. he said "if it got you, its damn sure gonna get me...f*** it!"

 

[E_americanus]

thanx for the info.

this has me wondering if this teeth trait is also common in other fish. like bowfins for example. i have not raised on yet, but that will change if i time the spawn out right this year. i made the mistake of liping the first one i caught like a bass, bad idea. they have some narly chompers, but i wonder if it would be a simmilar situation with their teeth to the gars?

i know all to well about the wild bite vs the captive bite. my big florida has got me a few times while hand feeding. i was helping someone land a larger longnose on the st. crouix and it got my fingers/hand pritty good, much worse then my fl could ever do. never got to see that fish well/long cause that was the first pass and the guy saw me bleeding and cut his line. he said "if it got you, its damn sure gonna get me...f*** it!"

i am sure there are similar situations with many other fishes, and i would also say yes regarding bowfin as we have seen that issue firsthand in comparison with captive specimens and many wild specimens--
--solomon

 

[Zfishies]

Wait wait soits 100% you can sex the gar? You know the difference between a male and female by just looking at it?