Pond Boss Forums INTRO Questions & Observations Male Largemouth Bass changing sexes

I remember that years ago there was a theory about why virtually all LMB over a certain size, perhaps three or so pounds, were female. One theory was that the males changed sexes after a certain age, or certain size, etc. Although I know this forum has discussed the fact that most large LMB are female I don't believe I've ever seen this sex change theory discussed here.

What is the current thinking on this?

Bing

I think female LMB are just bigger than males, period. Especially Floridas.

IIRC Hemingway wrote about big Marlins changing sex AND species after they got so big. There was a lot of speculation in times past about stuff we now know ain't so.

Another piece of the puzzle: generally speaking, most of the males have high natural mortality rates than females for many of our freshwater fishes (largemouth bass and walleye are two good examples). Higher mortality = shorter lifespan.

I'm not saying this is 100%, and I'm not saying it is the only factor involved, but it is true for quite a few fishes, and an important part of what we teaching our fisheries students.

Just to add controversy and scandal, consider the female praying mantis; when she's done with the male, she's done with the male.

I guess that explains the high mortality rate for males...

This may help a little explain the process and about male's reduced LE. Outside of this type change I have not heard of LMB changing sex.



The Progressive Fish-Culturist 51:146-148, 1989

Hormonal Sex Control of Largemouth Bass

GARY P. GARRETT

Texas Parks and Wildlife Department



Hormonal control of sex of fishes is a field of

research that holds many potential benefits. Control

is accomplished by administering a specific

hormone to fry before sexual differentiation occurs.

The administered hormone predominates

over the relatively small amounts of genetically

determined hormones and induces development

of either testes or ovaries. Once developed, gonads

then determine adult sexual characteristics. Thus,

a sex-changed individual has the genotype of one

sex, but has the phenotypic characteristics of the

other.

Hormonal control of sex can be used to produce

unisexual populations. This would be useful in

eliminating reproduction (particularly where

overpopulation is a problem) and in increasing the

proportion of a desirable sex (Schreck 1974; Goudie

et al. 1983). Female largemouth bass (Micropterus

salmoides). for exam pic, seem to grow faster,

live longer, and generally be better fitted for survival

under adverse conditions than males (Padfield

1951). Thus, supplemental reservoir stockings

of all-female largemouth bass might lead to

increased survival and ultimately larger fish.

A potential problem with applying this technology

to largemouth bass was suggested by Chew

and Stanley's (1973) conclusion that, for blucgills

(Lepomis macrochirus). "sex does not appear to

be labile, and is not readily altered from female

to male.'* D

Heck, over here we have intersex LMB! Eggs in the testes!
Best of both worlds!
(or worst???)