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Sex Ratio In Macropodus
February 27, 2012
6:29 pm
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plesner
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In a Danish language forum we've had a discussion about the sex ratios in several species of Macropodus. Especially M. spechti often produces around 90% males. We were wondering what kind of factors we could 'adjust' to get a more even sex ratio.

The only text I could find dealing with the topic of sex ratios in Macropodus species was 'Francis, R.C., The effects of bidirectional selection for social dominance on agonistic behavior and sex ratios in the paradise fish (Macropodus opercularis), Behaviour, Aug 1984. v. 90'. It's quite an interesting paper, but M. opercularis tends to produce fairly equal numbers of males and females, so we have to do some more searching.

Can anyone point me towards texts about factors influencing sex ratios in other species of Macropodus or tell a bit about his/her personal experience of getting a more even sex ratio in Macropodus species?

February 29, 2012
7:26 pm
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Matt
Málaga, Spain
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Hi plesner, Paepke mentions and speculates on this phenomenon in his book 'Die Paradiesfische' (1994). He seems to conclude there are potentially a number of factors involved, and that further study is needed.

I can scan the relevant section for you if you like, but it is in German.

Cake or death?
March 1, 2012
5:27 pm
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plesner
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QUOTE (Matt @ Feb 29 2012, 08:09 PM) < {POST_SNAPBACK}>
Hi plesner, Paepke mentions and speculates on this phenomenon in his book 'Die Paradiesfische' (1994). He seems to conclude there are potentially a number of factors involved, and that further study is needed.

I can scan the relevant section for you if you like, but it is in German.

Hi Matt.

I just reread chapter 3.3 in 'Die Paradiesfische'. It's been 15+ years since I read it, so I didn't even remember that Paepke had an opinion on this topic.

I'm considering trying to get my hands on Schwier's text on the same subject (which Paepke refers to), but where does one even start trying to find something like that from 1939? I'm not even sure I understand half of what's written about that particular publication:

Schwier, H (1939): Geschlechtsbestimmung und -differenzierung bei Macropodus opercularis, concolor, chinensis und deren Artbastarden. - Z. ind. Abst.-Vererb.-lehre. 77:291-335.

March 1, 2012
5:56 pm
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Stefan
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A combination of pH, dGH, temp and what not plays a role in that but I'm pretty sure there's no definitive clear cut answer/solution to the 'issue'. Trial and error seems your best option?

March 1, 2012
9:01 pm
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plesner
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QUOTE (Stefan @ Mar 1 2012, 06:39 PM) < {POST_SNAPBACK}>
A combination of pH, dGH, temp and what not plays a role in that but I'm pretty sure there's no definitive clear cut answer/solution to the 'issue'. Trial and error seems your best option?

Yeah, I kind of gathered as much. I just hoped to cut a few corners rather than having to do all the testing over again. /blush.gif" style="vertical-align:middle" emoid=":blush:" border="0" alt="blush.gif" />

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