basic concepts

[eshlasko]

I just returned from diving in Boracay (an island in the Philippines) ... and I was struck by an image that brought back memories from earlier dives in the Red Sea. To wit: I saw large anemones with entire colonies/families of clownfish -- many adults, but also many score tiny juveniles. I saw what looked like "family" groups of bicolor angels. In the Red Sea, I saw shoals of identically aged sibling anthias. My question to all: if fry hatch and are dispersed into the water, it seems inconceivable that there is a way such collections of identically aged juveniles would find their way back to their parents' anemone. It seems inconceivable that thousands of identically sized anthias would find their way together back with their "home" colony. When we try breeding these fish are we missing some basic point about how they spend their early juvenile stages?

What about pelagic breeders. Are we mistaken about where pelagic breeders eggs and fry go?

 

[billsreef]

While those fish might all of been the same species in those "family" groupings, some DNA sampling would have shown that they were not all brothers and sisters When larval fish settle out, they settle out into the proper ecological niche for the species. Nothing to do with finding siblings, just like critters flocking to the same niche. Looking a school of anthias and figuring they are siblings is like an alien flying in and looking at all the humans in Manhattan and figuring they are all siblings

 

[wiscsaltwater]

way too many big words

 

[tedr]

Bill, Please indicate if this makes sense as to what happens in the "family" group.

The fact that the "juvis" are all identical in size has nothing to do with their ages. When they settle into a "family" group, the dominant female and male are established. The "juvis" fall into the bottom of the pecking order, and as juvis, their growth is limited (stunted), regardless of their various ages. They will limit their growth as long as they maintain their position as asexual juvis. Should a juvi move up in the pecking order and replace a vacated dominant male position, he will increase in size, but still be smaller than the dominant female.

 

[billsreef]

The fun thing about fish is that there are lots of differences. If you look at clownfish for example, the family group will be composed of a large dominant female, a smaller male and then a bunch of smaller "juvis". In this family unit, size can have very little to do with age as you suggest. On the other side of the coin we'll use the example of schooling silversides. Their average life span is only 1 year, with spawning occuring during the new moon for the spring and early summer months. As a result the age spread in any given school will only be a few weeks to a couple of months, so they will not only be fairly uniform in size, but age as well. Of course you will find all sorts of variations in between with different species.