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Suggestions request for reporting interesting larval behavior?


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#21 centrarchid

centrarchid
  • NANFA Guest

Posted 03 December 2014 - 05:31 PM

Redspotted sunfish. I was hoping someone will chime in with similar observations on this or another species. Larvae and fry not bottom oriented, rather they are structure oriented immediately upon leaving the nest. Other Lepomis like bluegill, redear, green sunfish, warmouth, central longear and pumpkinseed very much avoid structure for at least the first couple of weeks although central longear might associate with bottom in nature. Note I state central longear or at least the upland variety we have in the midwest. The other longear we have in the Mississippi embayment is different critter. Western Dollar might do something odd as well. Latter two rear similar to redspotted in tanks but I had done no rearing in larger tanks with zones of open and structured like being done currently nor do I have observations on them as I do with the redspotted in the wild. This behvior may be extremely important in it dispersal effects, especially when habitats are fragmented.
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#22 gerald

gerald
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  • Wake Forest, North Carolina

Posted 04 December 2014 - 12:12 PM

Could the fry simply be reacting to where their preferred food is located, on structures or planktonic? Would fry of those species that usually avoid structure change their behavior and act more like redspotted fry in situations where there's not much food in the water column but plenty to graze on plants, branches, and fallen leaves? And does the father play any role in directing fry toward good feeding spots?

Gerald Pottern
-----------------------
Hangin' on the Neuse
"Taxonomy is the diaper used to organize the mess of evolution into discrete packages" - M.Sandel


#23 centrarchid

centrarchid
  • NANFA Guest

Posted 04 December 2014 - 01:55 PM

Possible but I am doubting it. A couple years back we made some northern bluegill and redspotted sunfish broods where they left nest on the same days. They could be distinguished at a glance even at swimup / exodus. When placed in a large circular tank with circular flow, the pure bluegill formed a torus around the standpipe where fish tried to stay a good foot away from walls or venturi pipe. In contrast the redspotted sunfish would associate with whatever structure was present. Both types in same tank at same time. I do not think this difference would be easy to pick out in a smaller tank without flow.

In a pond / stream setting the larval redspotted sunfish stack up around the plants while the larval bluegill form large mobile schools that avoid structure and stay up off the bottom but near it. The redspotted sunfish actually eat off the substrate / structure while bluegill eat only what the can find in the water column. Such small fish are hard to see unless you had a piece plastic to serve as a background.

We are at point where pictures can actually be taken so over break we will repeat the tank version and show you how they sort out. For giggles will run dollars as well.
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#24 gerald

gerald
  • Global Moderator
  • Wake Forest, North Carolina

Posted 04 December 2014 - 04:05 PM

Different behaviors in the same tank at the same time is pretty convincing -- good ole ecological niche partitioning.
What about father & fry interactions? Any herding or retrieving strays (like cichlids)? Do fry stay closer to their father if other fish (potential predators) are present?

Gerald Pottern
-----------------------
Hangin' on the Neuse
"Taxonomy is the diaper used to organize the mess of evolution into discrete packages" - M.Sandel


#25 centrarchid

centrarchid
  • NANFA Guest

Posted 04 December 2014 - 04:36 PM

Interactions seem purely so offspring can operate safely in an expanded area.
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