Cuttlefish sex vs. temperature of the eggs

squishy1

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#1
I was able to place 8 of my cuttlefish with the UCSD research lab to help lower the cost of feeding them all. While the guy was over, he was mentioning that the sex of the cuttlefish is determined shortly after the eggs are laid and its based on the temperature the egg is maturing at. It was something to the effect of higher temperatures cause the eggs to hatch male, while lower temps hatch females (or visa versa). After he left I tried doing some research on that and wasn't able to find anything. Is this true?

I ordered my eggs from blue world aquatics, so I'm hoping they are aware of how that works and raise the eggs at different temps to ensure different sexes (and ship different eggs to help make sure you get both sexes). I'm just hoping all this work isn't for nothing. I'd really hate to end up having all females or all males and not be able to breed them.
 

DeepBlueWonders

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#2
I'm not to sure about this. But I do recall an article that talked about temperature playing a role in the sex of Sea turtle eggs.
Maybe there is some truth behind this for cuttlefish. And if there is, I'm sure a warmer temperature would could a majority of one particular sex, but I doubt the entire clutch would be one sex.
 

DWhatley

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#3
I have not seen anything on temperature and sex but it is not far fetched. It would not be reasonable to expect the retailer to keep them a different temperatures, however, your source said that the sex was determined very soon after laying and anything a retailer would do would be well after that point since these are all wild caught.
 

neurobadger

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#4
I'm a bit skeptical about that notion.

I've seen broods of cuttlefish eggs that were apparently mixed in sex because, weirdly enough, the brother fertilized the sister's eggs later on.

It's possible that there could be a small temperature differential, with the eggs near one part of the cluster being male while the eggs near another part of the cluster are female .
 

gjbarord

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#6
I don't buy it. I've never read anything on the subject and never in any of my days at the NRCC did we alter temperatures to increase our male or female hatchling ratios.

Sounds like something with a bit of truth, but not a hard fast rule.

Greg
 

squishy1

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#10
the first ones started to hatch on June 22nd, so 13-14 weeks old as of this friday. i have a 13 week old with a 17 week old in my display tank and those two haven't really shown any interest in each other.
 

magnetar68

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#11
I am not sure about the temperature of the eggs specifically, but I have seen abstracts of studies which refer to sex ratios of clutches being affected by temperature (for S. Officinalis). Here is one reference (this seems to be a powerpoint of the same paper; slide 11 discusses temperature effects: colder means more females, warmer means more males). I am not sure how reliable this data is, but this is one source that partially backs up the claim that water temperature determines the sex ratio.

I was unable to find anything about the fact that it was the egg temperature as opposed to the general temperature of the water during the breeding period.
 

squishy1

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#12
That may work out to my advantage then. The past few weeks out here have been scorching hot, my tanks have reached in the high 80s. My display tank peaked at 89, but no losses. Winter is fastly approaching which should help keep the water temp at a constant 76-78. I'd much rather havce tons of females to one male, then visa versa.

I don't know the exacty sex ratio of my eggs since i sold some to UCSD, but from what I have left the males are definitely outnumbering the females. Theres consant fighting over the females, I've broken up a few fights that were getting pretty rough.
 

magnetar68

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#13
Again, this study is for S. Officinalis which lives in temperate water as oppsed to S. Bandenesis which is a true tropical species. (the mediteranean sea surface temp varies from ~13C-28C [55F-82F] (see here) whereas the Indonesian sea surface temps varies from ~24C-32C [75F to 89F]. I don't know enough about these two species to say with any certainty, but I would caution against assuming that these two species have a lot of temperature-related aspects in common given the differences in ocean temperatures common in their respective habitats.
 

squishy1

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#14
Well it looks like the first set of eggs was laid either today or yesterday. I think the high temps here are helping to accelerate things. From what I can tell there's about 20 eggs, half of which look good, the other half not so good. A few eggs don't have any ink in the egg, and a few of them dont have any egg, its just an embryo. At least its a good start!
 

DWhatley

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#17
As I recall from CuttleGirl's group, the early and late eggs did not do well but the ones in the middle of the brooding cycle survived.
 

squishy1

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#18
From all the reading I did before I got the cuttles, I read that numerous times as well. The viability of the eggs goes up with age and then hits a peak, and then precedes to decline again when they get older. I figure I would try to sell the first egg clutch for really cheap since out of 20 eggs, id guess maybe 4 or 5 would hatch. Especially since mine are still young, just about to hit 3 1/2 months.
 

DWhatley

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#19
You might want to watch the first eggs and not offer them for sale unless you see development.
 

squishy1

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#20
I really just wanted to gauge local interest in the eggs, and I'm glad I did because I didn't get any interest in them at all. I'm trying to plan ahead because they're laying egg after egg after egg. i think i'm past 50 eggs total now, 3 egg clutches. Since no one around here wanted any eggs I spoke to the Birch aquarium and I'm going to give all the eggs i have now to them.
 

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