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General Category >> Old World (annuals) >> Watters Method

Message started by ROBERT DEKEULENAERE on Jun 13th, 2023 at 6:18am

Title: Watters Method
Post by ROBERT DEKEULENAERE on Jun 13th, 2023 at 6:18am
Was trying to find a discussion of this method on the AKA site with no luck. Can someone point me in the right direction?

Title: Re: Watters Method
Post by Russell Feilzer on Jun 14th, 2023 at 11:25pm
While I'm admittedly not an expert on Nothos, maybe you should elaborate more on exactly what you are looking for.  Obviously it's something that Brian Watters professed or used so please expand your request and good luck.

Title: Re: Watters Method
Post by ROBERT DEKEULENAERE on Jun 15th, 2023 at 6:03am
Brian Watters used a method where he left annual eggs in the peat spawning containers in tanks for an extended period. Supposedly this caused the eggs to go in a prolonged state of diapause so they could be hatched out much later. In other words annuals with an egg incubation period of lets say 3-4 months could be stretched out to 1-2 years with no ill effects. I am looking for more detailed info on his method.

Title: Re: Watters Method
Post by Tyrone Genade on Jun 15th, 2023 at 12:52pm

An exhaustive search of my emails has not provided the email I was looking for where Prof. Watters described his method of Notho breeding and peat harvest.

If memory serves (a big if), he would harvest peat after long intervals in the aquarium. He would also use large volumes of peat so the peat can become quite anoxic. In theory this results in the eggs doing into deep diapause and the eggs will develop over a much longer time span. By this method a fish like korthausae where eggs can develop in 6 to 12 weeks will now take 4 months to 18 months! The big benefit of this method is that you don't have rapid development and end up being inundated with fry; also that because the eggs incubate longer you can maintain more species in the long run.

I hope that helps.

Title: Re: Watters Method
Post by Brian Watters on Jun 21st, 2023 at 1:36pm
The so-called Watters method for extending the incubation time for Notho eggs is not something that I deliberately set out to achieve. At one time I was maintaining about 150 tanks and a large number of different species and populations; with frequent collecting trips I also had a lot of new populations coming into my fish-room. I simply did not have the time to harvest the peat from all those tanks on a short time basis. Consequently, I was leaving the peat in the tanks for long periods, in some cases 2 months or even longer. As a result, the peat in the plastic containers in my tanks was becoming anaerobic causing the eggs to become locked into an early Diapause or resting phase, in the same way as what happens in the natural habitat.

This became my "normal" way of doing things, although for new species/populations I would initially collect the peat at one to two week intervals in order to get them quickly established and distributed.

After a few years of delayed harvesting, I noticed that the incubation times were, in many instances, becoming prolonged. My field work with Nothos had suggested that this was due to the fact that  I was inadvertently duplicating natural conditions where the substrate is strongly anaerobic, causing the eggs to become locked into an early Diapause.

Most hobbyists would regard an incubation period for many Nothos to be in the 2-4 month range because under the conditions that we usually maintain Nothos in our fish-rooms (e.g. harvesting peat every week or two) that is what happens. However, that is not what happens in nature because the dry seasons are significantly longer than that, suggesting that in order to survive such dry seasons the normal minimum incubation time must be correspondingly much longer than what is commonly experienced with captive situations (i.e. in our fish rooms). In other words, the norm in nature is for incubation times to be relatively long, probably at least twice as long, and for some eggs even much longer that that.

In my own case, there are probably other factors that also come into play: I have always maintained a relatively cool temperature in my fish-room (about 23 C), primarily for my own comfort when spending a lot of time there! It is a well-known fact that higher incubation temperatures can promote relatively more rapid development but, again, I use a temperature of about 23 C in my egg incubator as well. The dampness of the peat during incubation is also important in that higher moisture levels can, up to a point, also promote more rapid development. I tend to use relatively low moisture content when I bag peat and numerous people have commented on that when I have sent them eggs. To ensure that the peat does not dry out too much during incubation, I double-bag the peat (2x2mil plastic bags). I also do not leave a large amount of air in the bags (about 1:1 parts peat and air space) and that may also be a factor. Keep in mind that plastic bags do "breathe" to a degree.

Do not assume that the wetter the peat is the quicker the eggs will develop because if the peat is sodden then essentially what you will have is a situation developing as in the tank - the eggs will quickly find themselves in an anaerobic micro-environment and become locked into an early Diapause in the bag.

Hopefully, this explains the reason I think my incubation times are usually longer than most; however, it is not always a sure-fire way to increase incubation times because it may not be consistent, as it depends on numerous factors coming into play. You will still have to check the eggs at regular intervals to see how they are doing and act accordingly.

As an aside, two days ago I hatched out a few fry of N. pienaari KNP from a batch of peat that had been wetted twice before (yielding fry on both occasions); that batch of peat was harvested from a tank in the first instance more than 5 years ago - and the fry are perfectly healthy. While doing this I checked a few other bags of that species, collected a bit more than 3 years ago and all the eggs I saw were still clear!

Title: Re: Watters Method
Post by Russell Feilzer on Jun 24th, 2023 at 12:16pm
Thanks Brian, great explanation.  It's good to hear from you again.

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