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Zanzibar and spawning Nothos in the field
Hi all,
As most of you are aware, in June of this year, Barry Cooper, Ruud Wildekamp and myself undertook a collecting trip to Tanzania. Originally, this was to be a two-week trip with the focus on the southern coastal plains area of that country but we ended up extending the trip by 3 days and spent the additional time on Zanzibar Island at the beginning of our stay in Tanzania.
Our main reasons for going to Zanzibar were two-fold: a) to collect N. guentheri and N. melanospilus (that represent the only two Nothos present on the Island) and, b) to be tourists for a day or two and experience some of the very interesting historical aspects of the island as well as some of the many other tourist attractions such as the spice farms, red colobus monkey sanctuary, coral beaches, etc.
We arrived at Zanzibar town by hydrofoil from Dar es Salaam on the mainland and, after making some arrangements with our tour company, did a quick conducted tour of the old part of Zanzibar town (Stone Town), a tour of a spice farm, and then set off for the Jambiani Beach area on the east coast of the island where we had arranged to stay in a small guest house situated on the beach. This was a simple but very pleasant place to stay. One could literally step out of the front entrance of the guest house directly onto a white coral sand beach with the edge of the sea just meters away. We had the whole place to ourselves and the meals (mostly seafood) were excellent. Anyway, I digress......
Our second day on the island was devoted to looking for Nothos and in that we were successful, finding Nothos in 4 locations from which we collected live specimens of N. guentheri and N. melanospilus from two of them. The collection codes for these are:
N. guentheri Zanzibar TAN 97/2
N. melanospilus Zanzibar TAN 97/2
N. guentheri Zanzibar TAN 97/4
N. melanospilus Zanzibar TAN 97/4
At the time of collection it was 17 days before we would return to the Netherlands and North America and we had serious doubts that these Nothos would survive that length of time in plastic bags. Consequently, we decided to attempt to spawn them at the guest house. For this purpose, Barry and I had each brought a small plastic aquarium and a supply of peat pellets. We set up trios of N. guentheri TAN 97/2 and N. melanospilus TAN 97/2 and left them to it overnight. The following morning, in great anticipation, we collected the peat and inspected it in the sunlight, expecting to find masses of eggs. However, not a single egg was apparent in either bag. We wrote the exercise off as a failure but tied off the bags of peat and I threw them in a suitcase and forgot about them until I returned to Canada and even then, I merely put them in my incubator without a further inspection at that time.
Our third and final day on Zanzibar was spent sightseeing after which we returned to Dar es Salaam late in the day. The next day we set out on the main part of our trip to southeastern Tanzania. And that is another story.......
Amazingly, almost all of the N. guentheri specimens that we collected (both TAN 97/2 and TAN 97/4 populations) survived the 17 days in bags and are now spawning well in our fish-rooms. The N. melanospilus did not fare as well and none of those from Location TAN 97/2 made it back alive (although they did survive for at least two weeks). Most of the N. melanospilus from Location TAN 97/4 also succumbed but two males and one female survived and these are doing well and spawning so it is secure in the hobby.
A few weeks after returning home, I decided to inspect the two batches of peat from our attempted field spawning and was surprised to find a few eggs in the N. guentheri batch (about 3 was all I could find). No eggs were evident in the N. melanospilus peat. Although we had live wild specimens of N. guentheri TAN 97/2 in our tanks, I was keen to attempt to hatch the field spawning just to prove this method does work and can be used as a back-up precaution against losing a wild collection altogether through subsequent loss of the fish in the field.
A few days ago I wet both batches of peat and was surprised to get as many as 15 fry of N. guentheri TAN 97/2 and also 3 fry of N. melanospilus TAN 97/2. With luck, I will get a pair out of the latter so that we can get that population established as well.
One could ask why we don't attempt field spawnings of everything we collect as added insurance. However, this method does not always work and there are practical difficulties in that at the end of a long day of collecting and travelling, which can end well after dark, there are other important tasks that have to be done (such as changing the water in large numbers of fish bags, meals to be eaten, etc). Furthermore, if one intends spawning Nothos in this way, then it must be done on the same day that the fish are collected. Many wild Notho females will spontaneously drop their eggs during their first couple of days in the bags and, without food, they tend not to fill with eggs again. I also suspect that even if they don't drop thier eggs, these are "absorbed" internally as the fish begins to starve.
This is not the first time I have attempted to spawn fish in the field and I have had considerable success doing this when collecting in Malawi. Mind you, conditions were a bit different there because I had proper holding facilities for the fish so it was just a matter of transferring a trio from a large tank to a smaller one for a day. In 1995, we attempted to spawn N. sp. Kilombero TAN 95/4 overnight, using a bucket as the "tank". No eggs were produced. In Zambia during March-April of this year I also attempted to spawn N. kafuensis Kayuni ZAM 97/1 in the field, also with negative results. This surprised me because the fish were mature, the females loaded with eggs, and certainly after I got them into my fish-room they produced phenominal quantities of eggs. The first N. taeniopygus to be introduced to the hobby (the Kondoa KTZ 85/5 population, collected by Wildekamp, Seegers and Roth) were spawned in the field and the fish that we have in the hobby are, apparently, derived from those eggs as the wild fish never made it back alive.
Well, this has been quite a long story about very little but, hopefully, it will be of interest to someone and I would welcome any comments or questions.
Brian R. Watters
University of Regina
Regina, Saskatchewan S4S 0A2, Canada
Ph: (306) 584-9161 (home); (306) 585-4663 (work)
Fax: (306) 585-5433
E-mail: bwatters at sk_sympatico.ca