Pond Boss Forums INTRO Questions & Observations Are female smallmouth larger than their male

counterparts in the way it is with largemouth bass? I'm not seeing much on the Internet and the only thing I've found is one entry that says there is no size difference. I don't always believe some of those entries as I've see a lot of hearsay on the Internet.

I'm asking because I'm moving smallmouth to my hatchery pond and I seem to have two size groupings. The large ones are not obviously gravid but stocky. Perhaps it's just a little early yet?

Anybody know for sure?

CB1: Maybe not for sure but one study - of R.J. Danehy & N.H.Ringler 1991. A total of 110 bass were sampled.(Ecology of smallmouth bass (Micropterus dolomieui) in the nearshore of Mexico Bay, Lake Ontario.) they say ""If one considers all other age classes (ages 1-8; other than 9&10 yr old fish), it appears that the differences in those age classes 1-8 were insufficient to consider growth rate of male to be more rapid than females."" I also note in my article that male and female SMB grow at about the same rate in Part 5, Rule 3 Growth Rates, of "Growing Smallies Into Trophies". Pond Boss Magazine Nov-Dec 2009.


FYI for those interested: diet of SMB showed distinct differences in feeding habits influenced by substrate type. On sand bass were almost entirely piccivorous with no invertebretes except for a few crayfish in midsummer. Diet of bass inhabitating cobble/rubble fed heavily on crayfish and crays represented the entire diet in September. Overall SMB associated with shoal type structure was a benthic feeder whereas over sand substrate they were primarily pelagic feeders. This is why SMB are often considered opportunistic feeders.

Growth of SMB begins when water temps reach 50F. This temperature coincides with when my YP begin actively feeding at the surface. Optimum growth for SMB in the lab was considered to be 74-84F.

In another study Cantin & Bromage found that SMB begin spawning when the day length is 14 hrs and water temps reach and stabilize at 64.5F. These data were based on laboratory studies. Current day length for our area is 13hrs 19 minutes.

Thank you Bill, invaluable stuff for SMB fans.

More valuable information for SMB fans is SMB are surviving the second year in a Texas small pond after stocking of SMB fingerlings in 2010. No LMB are in this pond. The interesting thing besides eduring hot dry weather last year in Texas, is this particular pond is turbid due primarily to suspended silt/clay and minimal phytoplankton is present due to silty conditions. It is not known if these Texas smallies have or will sucessfully spawned to recruit YOY. Stay tuned for more info on this topic.

So trying to sex them by size would be unwise?

Maybe not unwise, but surely not the most accurate way....

True but I hate to put too many fish in the pond just to makes sure I have enough of each sex!

I think I'm going to have to find some catheter tubes, anesthetize the fish and see if I can determine their sex.

I stock 14-20 just to be safe...don't want to wait until gravid as I'm afraid I'll be too late. Fishing out 20 adults isn't too hard, but it's kinda a pain. I wish I have a better system...with Condello around it doesn't take too long to get em corraled tho.

There are alternative systems for SMB. One can use the fry transfer method or make portable nesting boxes. SMB fry do not school well and scatter quicker after swim-up compared to LMB. When the fry have almost hatched move the nesting box to another pond. Both methods require an underwater viewer glass of PVC tube 3-4" dia fitted with glass on one end.
In fry transfer method, nests are inspected daily with viewer. When eggs are found the nest is tagged or marked to indicate when eggs should hatch. In warmer water of high 60's to 70F egg hatch can occur in 2-4days. Spawn to swim-up is usually 10-21 days depnding on temperature. When eggs hatch a retainer screen is placed around nest to confine fry. Retainer screen is often about 3ft in diameter & 40" deep, covered with window screen. Swim up fry are then dipped out of retainer screen enclosure and transferred to rearing pond.

Portable nesting boxs are built using 1X4 lumber, 24" square with window screen bottom. Inside a 16"X16" 2" high hardware or plastic mesh 'basket' holding 1"-3" rocks is placed in the nesting box. The mesh basket also could be made from 1/4 nylon seine netting that has surplus material around the edges to create a 'bag basket' when edges are pulled together. When the fry hatch and before swim-up the fry are harvested by lowering the pond level and gently moving the 'basket' up & down washing the fry through the rocks and onto the screen bottomed frame. Rinse fry into a bucket or tub for transfer.

I'm aware of this Bill as it's in the "black book." However it's not practical in my steep sided pond and frankly it seems to be a lot of trouble.

I think I'm going to either have my vet do a portable ultrasound on the fish to see roe (anesthetized) or wait until I am closer to the spawn and do a catheter probe.

Is that covered under obama care?

No need with vet care. It's actually affordable!

My vet probably wouldn't charge much for an ultrasound of a few fish. I'm going to call tomorrow. I'll take in about 10 smallies in a large cooler and she can bring out the ultrasound. Worth a try!

She used a small portable ultrasound the other day for my dog as the dog has a bladder infection. The dog's bladder showed up clear as day! Entire bill was $54.

CB1 - Maybe with ultrasound you can see if there is an outward difference between males and females.

Cecil, you never cease to amaze me in the high tech things you do in the name if fish culture. Ultrasound on bass to look for eggs! Pretty cool... HAHA

It may sound crazy but if I was a serious producer that wanted to produce a lot of smallmouth fingerlings at a one or two dollars an inch or more, using a portable ultrasound, if it got the job done quick and easily wouldn't be so crazy.

If you get a pic of the ultrasound can you share it ?

Of course! Appointment is at 2 P.M. Wednesday.
She didn't think anesthesia was necessary. I said actually it is as these are smallmouth bass -- unless you want to get really wet!

No promises on if this will work but I will take pictures and we will give it a shot! I'll tag the females with a temporary clip on tag on the lingual tissue and get close ups of the urogenital orifices of both egg laden fish and non egg laden fish.

She offered to come out to the farm but she's only 3 miles down the road and I can easily catch a few, put them in large cooler in the back of the SUV and head down the road. I will line the back of the wife's SUV with plastic of course!

Speaking of ultrasonic stuff.

I was wondering if any one knew if ultrasonic level sensors would have any negative effects on fish? I could just pulse it every so often, and not run continuous. One less thing to have to clean.

Don't know but I know a aquaponics producer that uses vibratory feeders to produce vibrations to dislodge waste particles in his media for his media based plants.

I can see how that works. I use to design and build vibratory bowl and track feeders. Pretty simple. Choke coil mounted on a spring with a variable transformer. I should have a few choke coils laying around, and I know I have a couple variable transformers. I was thinking about building a vibratory fish feeder. If you know how to tune them, they work really well.

Cecil:

I have a tagging gun from Greg Grimes. Mike has red and yellow non-numbered floy tags. All I have are the yellow numbered floy tags. You could mark them permanently if you want.

I can have it in the mail tomorrow and it'll be at your place on Wed.

Scott,

Thanks for the offer but I'll pass. I have a clip on tag I'll take off just before I plant. I don't want to do anything that will make them less valuable when i go to sell them. If I really wanted to mark them permanently I'd cut off a dorsal spine or two.

I've also see those tags cause a heck of an infection.

True, I keep forgetting about the market.

The offer is much appreciated though.

Any discoveries from the ultrasound today?

Here's the follow up in this thread about my impending trip to the vet to do some ultrasound on some of my broodfish size smallmouth bass. The idea was to see if I could see some egg (ovary) development in some of my smallmouth broodfish. I wanted to test my hypothesis that the larger fish are females as I seem to be catching two groups of fish: larger robust fish and much smaller fish albeit healthy looking. However I'm just not seeing any obviously gravid fish like I do in my other species of fish, but I want to move them to their spawning pond ASAP.

Par for the course, I was running late due to some long distance taxidermy errands and was able to capture only 5 fish in a short amount of time to make my appointment. Only one smallmouth was distinctly larger than the rest.

Here are two after removal from the hauling tank in the process of being sedated in a five gallon bucket by some Finquel.



Here are Dr. Jennifer Lortie and I attempting to get something with the portable ultrasound.



Here is a pic of the ultrasound screen which doesn't show well in the photo due to the glare of sunlight.



The ultrasound wasn't very conclusive so Dr. Lortie suggested we try an xray.

Here she is getting one prepped for the x-ray machine.



Here are the two fish on their respective x-ray. Both are labeled # 1 because Dr. Lortie was shuttling back and forth to clients to accommodate me and was bit rushed. LOL It's obvious they are different fish as one is bigger than the other. Note how well the swim bladder sticks out!





Here is the larger of the two:



Dr. Lortie hasn't done much with fish yet, but believes we may be seeing some ovary development in the larger fish up to the urogenital opening, and whatever they are do appear to be somewhat granular. If they are ovaries I'm struck by the lack of impressive development past the middle of April. Perhaps they will develop faster closer to actual spawning? At least that is the case with my yellow perch.

Or course possibly finding ovaries in just one sample hardly backs up my theory that the large fish are females, but I will keep checking in the main pond as they get closer to spawning time.

BTW one of the bass spit up this partially digested frog or toad just before I put all five into the brood pond. It may have been the smaller of the two as Dr. Lortie was sure she could see something in the stomach of the fish. Sorry it's so blurred; I'm not sure what happened. The head and eyes are in the bottom of the picture pointed down.



Next I will catch several fish, sedate them and get close ups of the urogenital openings. I was planning on doing so with the fish from today but forgot to. I think I did see a difference in at least one of the fish having more of keyhole shape verses just round vs. another fish.

BTW my vet is a real trooper as I could see most other vets turning me down for this "fishing expedition." She also only charged me $35.00 for all the trouble although she was clearly very busy.

Wow, ultrasound and X-ray on the same visit....that's a pretty accomodating vet! Did they take down your insurance information?

That's pretty cool, Cecil.

We can only wish our healthcare costs were similar to a vet bill. I've seen some high vet bills but nothing like people care!

Vets are indeed way cooler than doctors....and dentists.....

Uh oh!

My dentist bills are very reasonable too. A blood test at my doctors' cost me more than my dentist and vet bills combined!

Very cool Cecil, that vet is a saint.

She sure is. I've invited her to come on the website as she needs some advice about her father's pond.

Especially Dentists! Anti-Dentite

Seinfeld?

You might be a Pond Junkie if............