what kinds of jacks are these?

[archman]

Students on a field trip caught these little jacks in a bag seine off the beach on Mustang Island, Texas. I've currently got them in a lab aquarium, but haven't had the time to figure out their I.D.'s. I thought I'd let the board have a crack at them first; save me some trouble, possibly.

I first thought they were leatherjackets, but closer examination leads me to think they're juveniles of some larger species. Possibly two species.

 

[Rick Murchison]

"Leatherjacket" is a common name we use for Triggerfish 'round here I'm curious what y'all are using that common name for...
Those are definitely juvies; if I were betting I'd bet Caranx crysos (hardtail/yellow tail/blue runner), but at that stage they could be just about any of the taller bodied jacks (Crevalle, Horse eye etc). I don't believe they are Amberjack or Bar jack.
Rick

 

[rhine64]

Definitely not leatherjackets. They are very distinctive with a very pointed head and a more angular body. These are likely either florida pompano or permit, depending on the counts of the dorsal and anal rays. Let me know what you figure out.

 

[Rick Murchison]

Definitely not leatherjackets. They are very distinctive with a very pointed head and a more angular body. These are likely either florida pompano or permit, depending on the counts of the dorsal and anal rays. Let me know what you figure out.

Agree they could be pompano or permit too. Bet's still on hardtail, though
Rick

 

[archman]

"Leatherjacket" is a common name we use for Triggerfish 'round here I'm curious what y'all are using that common name for...

Texans call triggerfish, uh, triggerfish. Leatherjackets are leatherjacks, little teeny jacks under the genus Oligoplites. They have a bunch of common names worldwide, but I've never heard anyone in the states call 'em anything other than the leatherjack/leatherjacket combo. No wait, some dude in Galveston called 'em needlejacks once. Just had to be different...

About the only time I've caught leatherjacks are in beach seines, so it's likely most fishermen aren't familiar with the things. They never get very big.

I know the fish above aren't baby permit, as we caught some juveniles in a trawl and they have much deeper bodies. But baby florida pompano might not be an unreasonable guess. They're yellow-finned, anyhow. But so are yellow jack and horseeyes. We get all three species offshore. But the little fellow with the reddish-black fins, he's a puzzler.

Dang things won't sit still long enough in their aquarium to get diagnostic photos. They sure like flake food.

 

[Rick Murchison]

Texans call triggerfish, uh, triggerfish. Leatherjackets are leatherjacks, little teeny jacks under the genus Oligoplites.

Just for grins I Googled "Leatherjacket" - lots of filefish/triggerfish - I reckon the jack's there if I look far enough down the list, but this is the first time I've ever heard the name applied to a jack I Googled "oligoplites" and sho' nuff, there are "leatherjack" and "leatherjacket" jacks... Learn somethin' every day, by golly!

But the little fellow with the reddish-black fins, he's a puzzler.

The color variance is the first thing that made me think Caranx crysos, which go by (at least in our part of the gulf) "yellow or yellow tail jack" when their fins have a yellow tint (yeah, I know the real yellow jack is a different animal), or "blue runner" when their fins have the blue/black tint, or more commonly "hardtail" either way. I think the two photos are of the same species.
Rick

 

[MichaelBaranows]

juvenile Permit

 

[archman]

Okay, thanks to all you guys' help, the list has been narrowed down to two, Florida Pompano and Blue Runner. Dangit Mike, I just said they weren't baby permit...

I'm leaning towards the pompano after looking closely at the caudal peduncle and hard spines, but blue runner's are so similar in appearance, I'd rather not rule them out until I whip out a formal book. My students need a final ID for their field reports.

FishBase says baby pompano like to hang out near sandy beaches, but that doesn't mean baby blue runner's don't.

 

[Rick Murchison]

FishBase says baby pompano like to hang out near sandy beaches, but that doesn't mean baby blue runner's don't.

Well, adult Blue Runners certainly do... I reckon the babies would too
Rick

 

[wreckchick]

Pompano and Permit are damn near the same thing except for some spine count thing. If you've seen baby Permit and those aren't them, then I'd go with Blue Runner, but my money is still more on a Jack Crevalle or Bar Jack kind of vein.

R