I need pictures of brown and rainbow trout with their anal fins extended

[taxid]

What geese? 

No I'm seriously pursuing this.

Did find a Canadian reasearch paper online that discusses it but they want me to pay a fee to access it. I will probably pay the fee when I get back from vaca.

[seamonkey84]

I think if it was as easy as sexing livebearers, like little guppies and mollies, it would be more published information. With some fish like cichlids you can tell males by how the dorsal and anal fins taper out more vs females being rounded and shorter.

[taxid]

I think if it was as easy as sexing livebearers, like little guppies and mollies, it would be more published information. With some fish like cichlids you can tell males by how the dorsal and anal fins taper out more vs females being rounded and shorter.

That may be true but I've been told by state and federal hatchery managers recently after sending out some queries that there is no incentive to even know the sexes until they are sexually mature for spawning purposes. By then it obvious and there is no need to look at the anal fins.

Two of them have said it may or may not be true but they've never checked or had a reason to on sexually immature fish.

[seamonkey84]

I guess from a hatchery stance that makes sense, but not if you’re really tying to know everything you can about the species as a biologist. Granted it’s not like there are thousands or millions of people watching these fish in their tanks at home do their thing.

[Fish Farmer]

That may be true but I've been told by state and federal hatchery managers recently after sending out some queries that there is no incentive to even know the sexes until they are sexually mature for spawning purposes. By then it obvious and there is no need to look at the anal fins.

Two of them have said it may or may not be true but they've never checked or had a reason to on sexually immature fish.

This is really got me interested. We actually are looking at selecting fish before spawn. For instance we have a strain of steelhead that at sexual maturity( age three and age four) some are bright and shiny and not ripe at all. I actually held fish another year, just to see if they ripened...they are still shiny at age four. It appears that they are all "females", saying this because generally in our populations when they mature there is a 50/50 mix of boys to girls. The shiny steelhead percentage of around 17% added to the ripe females was roughly 50% of the population. If we can pick out this shiny component early on we can save on feed and space. Usually by age two the boys can be sexed.

[TightLinesMaine]

Really doubt that holds true for all brown &/or rainbow trout.

[taxid]

Really doubt that holds true for all brown &/or rainbow trout.

You may be right. I tried sexing yellow perch when they were not spawning by the appearance of their urogenital openings. Even that is only 90 percent.

[taxid]

This is really got me interested. We actually are looking at selecting fish before spawn. For instance we have a strain of steelhead that at sexual maturity( age three and age four) some are bright and shiny and not ripe at all. I actually held fish another year, just to see if they ripened...they are still shiny at age four. It appears that they are all "females", saying this because generally in our populations when they mature there is a 50/50 mix of boys to girls. The shiny steelhead percentage of around 17% added to the ripe females was roughly 50% of the population. If we can pick out this shiny component early on we can save on feed and space. Usually by age two the boys can be sexed.

The female tiger trout I have are like that. Stay pretty much silvery. And I can't sell them worth a darn as the taxidermists only want the brightly colored males with distinct markings.

BTW tried sexing smallmouth bass with X-rays. Only thing that stood out were the bones and the air bladder. Egg sacs did not show up in the X-rays. Ultrasound was even worse.