Amusing salt water fish: coelacanths

[anewbie]

Read this article - these fishes are preg. for 5+ years !
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Weird 'living fossil' fish lives 100 years, pregnant for 5

The coelacanth — a giant weird fish still around from dinosaur times — can live for 100 years, a new study found. Females don’t hit sexual maturity until their late 50s, the study said, while male coelacanths are sexually mature at 40 to 69 years. Coelacanths, which have been around for 400...

news.yahoo.com

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sadly they are a bit rare so you can't run out and get one (i think - maybe someone is breeding them for hobbists )

 

[Colin_T]

That's interesting but I have my doubts about the 5 year pregnancy bit. No animal on the planet carries young for that length of time, even elephants have a shorter gestation period (18 months), and whales (between 1 & 2 years depending on species). Sharks carry young for 6-12 months so 5 years is probably a bit long. It would be interesting if it's true though.
I wonder what evolutionary reason there would be to carry developing young for that long?

 

[Abaddon]

Greenland sharks live much longer than that (I think the oldest specimen was estimated to be almost 400 years old), and although their gestation period is officially unknown, some scientists speculate it might be between 8-18 years, so I guess you never know. Maybe one day we'll be able to study them more extensively & will be able to know for sure.

 

[anewbie]

From the article I suspect that the reason gestation period is so long is they have a very slow metabolism. I did a bit more reading on them - only around 8 have been found mostly by fishermen (which seems odd because I thought they lived in fairly deep waters); there are no known live specimens in capacity.

 

[Tacocat]

These guys are incredibly cool. They're living fossils, and were considered extinct until a fisherman in Africa caught one by accident. These guys are really rare, and I don't think they have ever been kept in captivity, and although people have tried, they are seriously endangered, and their gestation period is long, so I don't think the reproduce particularly fast. Good thing nobody dares trying to eat them.

 

[Jan Cavalieri]

I wonder if their gestation period is so long because they are trying to avoid over-population of their own species, especially if there are relatively few predators. Imagine, if you lived 500 years and reproduced 5 babies every year vs. 5 babies every 5 yrs.

We always think that high populations means the species is successful but in this case it would just lead to overpopulation and if your food supply is limited you don't want your grandchildren eating up all your food!!! Most of todays fish are relatively short lived and therefore must reproduce quickly especially since they have lots of predators.

 

[anewbie]

I wonder if their gestation period is so long because they are trying to avoid over-population of their own species, especially if there are relatively few predators. Imagine, if you lived 500 years and reproduced 5 babies every year vs. 5 babies every 5 yrs.

We always think that high populations means the species is successful but in this case it would just lead to overpopulation and if your food supply is limited you don't want your grandchildren eating up all your food!!! Most of todays fish are relatively short lived and therefore must reproduce quickly especially since they have lots of predators.

I doubt it; I would presume gestation is slow due to metabolism being slowed due to native habitat.