197 replies to this topic

[centrarchid]

This effort is resuming.  Methodology now better enabling more likely fertilization.  Recognizing behaviors indicating spawning imminent now easy.

 

Overall setup.

 

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Male and female coordinating signals and lining up to spew.

 

A pile of eggs in corner behind crevice the fish spewed into.

 

Most of clutch I was able to remove by siphing pile above.  Probably a similar number of embryos were spewed into the fibrous materials attached to brick.

 

Embryos will be incubated in blue buckets as shown.  Best is water kept shallow.  Tomorrow brood will be split into petri dishes.  Hatch percentage important this round because I will attempt to rear these guys in mass.

 

 

 

[centrarchid]

First clutch has six eggs gone white after only 90 minutes.  Second brood smaller and produced about 15 minutes ago.  Males are partial to eating loose eggs to a degree abdomens appear distended.

[gerald]

Just a reminder for those not familiar with the peculiar spawning method of pirate perch:  The female's ovipositor is just behind her gill covers.  She inhales backwards as the eggs are laid, drawing in eggs and sperm through the opercular opening, then blows them out through her mouth.  Centrarchid and one of his colleagues were the first to document and publish this behavior.   Thanks for the update!  And thanks for keeping it in the old thread with pirateperch's larval pictures.

[centrarchid]

Note methods similar but not same.  Challenge I had in beginning is fish would often not hang out around spawning area provided.   This overcome by shading entire area where fish are intended to spawn but so area below does receive direct light coming from side.  Arrangement approximates root wads under cut bank stream.  Fish went straight intended area and remain there even when not courting.  Dominant male stays in actual spawning area even when females not present.

 

Male does some very goby-like behaviors as part of courtship Bill Poly would be interested in.

[centrarchid]

Third female yet to spew.  Dominant male appears to be antisocial towards those approaching the spawning area.  When fish not spawning they act like Pirate Perch; lazy.  They appear to have consumed all eggs not protected in crevices or spawning media.

[centrarchid]

Female 3 spewed today.  First clutch total bust in terms of hatch (presumably overripe at time of spewing).  Clutch 2 doing very well and likely start hatching tomorrow.  Brood 3 appears viable although clutch deposited between brick and intended spawning site.  Next try crevices will be used instead of the substrate approximating rootwads.

[centrarchid]

Hatching of second brood starting early this morning.  That means about 5 1/2 days.  Females are filling up with eggs again even though being fed less than a maintenance ration.  That means they will be very poor when they are done producing eggs.

[centrarchid]

Approximately 100 prolarvae have hatched and at least that many more to go.  Now is time to start working on larval rearing setups.  Larval rearing will have at most 20 fish per container where major water changes will comes from well.  Brine shrimp hatchers will be used to meet first feeding needs.  A couple waterflea culture will be setup so they can be used after a week or so of feeding.  Problem I may have is brood 3 looks viable as well.  I may try and setup a larger tank for those in barn where observations and control will be compromised.

[gerald]

Chopped blackworms would probably work once the fish reach ~ 15 mm or so.  Do you culture any grindalworms, blackworms, etc?

[centrarchid]

I have never cultured such.  I might give is a try just for fun.

[centrarchid]

Prolarvae are now righting themselves and swimming strongly when disturbed.  They are dark enough to contrast strongly against the bottom of the dark blue bucket bottom.  It is time to split them out into several 10-gallon aquariums.

[centrarchid]

Estimate of number of prolarvae is about 135 in the older cohort and about 30 in the second cohort.  The elder fish do seem aware of what goes on around them and will swim in a coordinated way from stimulus.  They are also concentrated in shadow area.

[centrarchid]

Larvae have been transferred to a muck bucket in lab supplied with well water providing a residence time of about 12 hours.  Larvae are largely sedentary.  Students will apply brine shrimp nauplii twice daily (0800 and 1600) in excess.  Larvae have bellies but feeding activity is not as obvious as will similar sized sunfish and minnows.  

 

 

[littlen]

Where does the excess, 'muck bucket' water drain to?  The floor then to a floor drain?  Or is it captured in the sump and recycled through the system?

[centrarchid]

It drains onto concrete floor. Drain present although water will not reach it as anything more than a damp spot.  I will upgrade so water filtered through sand.

[centrarchid]

I have a better idea.  Water replacement is slow enough wicking can be used to prevent escapement.  Wicked water will be collected for confirmation process works.  

[centrarchid]

So far no water has escaped.  Catch tub can be chlorinated.

[centrarchid]

Here is approach will stand for next several days to allow flow through.  Residence time for muck bucket is now almost two days even though wick reduces working volume by about 1/4..  Overflow leaves via wick to fall into white 1-qt container allowing rapid visual inspection for escapement.  Water overflows that container into a 5-gallon container which is emptied every 12 hours.  As dry bucket is positioned about 20 g of powdered bleach is added to it.  Bucket is at best 2/3 full by time it is dumped.  Significant problem is less thermal control.

[littlen]

What is the need for disinfecting the wastewater?  Does it not go to the sewer system?

[centrarchid]

Yes, although snail traffic on floor and in plumbing potentially transfers pathogens/parasites up into other systems. These pirate perch are relatively clean because tank spawned but you did get me thinking.