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RE: collection codes
Bill Gallagher wrote:
>
>The codes as currently used start with the year start
>with the year of collection, which is a very useful tool
>for telling how long an aqurium strain has been in the
>hobby, out of the wild. It can be used as a rough
>indicator of how many generations of inbreeding have
>occurred in that strain.
>
I agree that the actual year of collection must always be used for repeat
collections from the same site in order to keep track of how far removed
they are from wild (as I mentioned in one of my earlier letters).
>
>For example, the Beira '91 and Beira '98 strains of
>N. rachovii are presumably the same "species".
>Somebody (Brian?) could tell us if they were
>collected from the same pool on the left side of the
>road, or next to the airport, or whatever.
>You could probably "cross" the two collection strains
>with no interspecific hybridization problems and the resulting generations
>could be fertile.
>
>But the '91 strain is now ~seven generations removed
>from the wild and might be a little degraded due to
>typical aquarium husbandry of breeding brothers and
>sisters for many generations. Furthermore, the '91
>strain all descend from a single female and a few males.
>The '98 strain now available in the hobby as f1
>(first generation) is from a much large number
> of imported wild fish. The more recent strain should
>have more genetic variability left in it and would
>potentially be more valuable than the other strain
>at this time.
>
The '91 population was collected along the airport road and it is my
understanding that the '98 population was from a different location (but
also on the outskirts of Beira). I have no detailed information about the
'98 site but I will get the details of both locations early next year.
Yes, you probably could cross the '91 and '98 populations, but why do that ?
As Bill points out, the '91 "strain" was derived from a single female and
the strain deteriorated very quickly in the hobby. The '98 collection
provided a much larger gene pool so, hopefully, we will get better quality
fish over the long-term. For a few months I had a spawning group of 12 males
and 25 females in a large tank so if that doesn't provide a good start I
don't know what will.
What may not be generally known is that in both '91 and '98 N. kuhntae was
collected from the same locations with the N. rachovii. The "Beira '91"
strain is still in the hobby and was derived from a group of specimens that
made it back alive. In '98 only a single trio of N. kuhntae survived (I
suspect that was all that was collected) and I received them. I was able to
spawn them but the eggs are not yet developed so an F1 generation has not
yet been produced. They will be introduce to the hobby in due course.
However, what is interesting is that I could discern some differences in
color pattern between the single '98 male and those of the '91 collection. I
realise that one specimen does not constitute a representative sample but
once I have an F1 generation I will be able to determine better if, in fact,
there are differences. Another illustration of why populations should not be
crossed ?
>
> Aphyosemion australe were collected from a
>small stream 18 km from the Libreville Airport
>in the direction of Cap Esterias, Gabon, by Legros,
>Eberl, & Cerfontaine in 1993. Their collection code
>was LEC 93/6. Eberl, Tirbak and another collected
>at the same site in 1996. Their collection from the
>very same site is coded EBT 96/27. The LEC 93/6
>strain is not in the hobby, but the EBT 96/27 strain is.
>The current strain WAS NOT collected by E,B&T in
>1993. I do not agree with the commenter that this '96
>strain should be known as LEC 93/6. If it was, then
>you'd have to call it something unworkable such as
>"the 96 collection by EBT of the LEC 93/6 site".
>Let's not go there.
>
I agree entirely, Bill.
>
> Now, having argued that the inclusion of the year of
>collection is a useful datum in the collection code,
>I would like to point out we have a "millenium
>bug" problem facing us shortly............
>.....THE CURRENT SYSTEM IS NOT GOING TO
> WORK MUCH LONGER.
Yes, this has occurred to me also but I have decided not to get too excited
about it at this stage. We will figure out a modification of the present
system in due course. (These are the sorts of problems that can be discussed
and generally resolved over a few beers at the end of a day of collecting. I
have a couple of collecting trips planned for next year so there will be
plenty of opportunity to work something out !)
Whatever system one comes up with there will always be the risk of ambiguity
if the location designation is changed or truncated in any way. Even the
present system is subject to that.
>
> ......If you want to use the GPS location, fine.
>
>
It is not practical to incorporate a GPS or map grid location reference into
the location designation attached to the name of a fish. I am not sure if
this is what is being suggested here but it is a matter that Gordon
Wilkinson raised in a letter a week or two ago. Can you imagine the uproar
if we introduced a Notho into the hobby with the following name, or
something similar:
N. albimarginatus "Kiparanganda E39-10.31/S07-11.40 TAN 97/40"
Other grid referencing systems are even more obscure. For example in Canada
we use the UTM grid system in which a location will always include one 6
digit number plus a 7 digit number as well as "E" and "N" identifiers. Try
incorporating that into a fish name. The other problem with grid references,
and also longitude and latitude for that matter, is that in order to use the
position reference properly you require suitable highly detailed maps. What
is the point in having very precise location information when your reference
map has (for example) a scale of 1:500,000 ? Detailed maps are not always
available for East African countries and even if they were, to get complete
coverage for the average collecting trip would cost a fortune. Collectors
may feel it worth investing in such maps but you can be sure that the
average hobbyist will not (and justifiably so).
I am not arguing against the precise determination of the location in the
field. Obviously, this is an essential bit of scientific information that
must be recorded. In spite of what has been said about the "inaccuracy" of
GPS data, this is still the best method for determining the locations of
collecting sites in the field. There is a far bigger error in working it out
from a map. Firstly, one has the problem of the scale of the map; without
highly detailed maps the determination of long. and lat. becomes a rough
estimate at best. And I have already mentioned the problem regarding the
availability of detailed maps. Secondly, to determine the position by map
only one would have to know the distance of the location from the nearest
town, bridge, etc. That in itself is a major problem. Where do you start
taking the distance from - the center of town (if that can be determined),
the edge of town (and with the sprawling nature of most East African
villages and towns, that is also rather vague) ? And if you are using
someone else's data to find a location, how do you know where they starting
counting the distance from ? Another very big problem is the fact that the
distance measuring devices in vehicles are never calibrated exactly the
same. From experience, I know that there can be as much as a 10 percent
difference from one vehicle to the next and that can make re-locating a
collecting site extremely difficult. Actually measuring or tracing off a
distance along a road on a map is also difficult (unless the road is dead
straight). And, yes, I know there are devices that allow one to do that but
they don't work very well either (unless you have a very expensive one).
If one has to re-locate a collecting site, GPS data is by far the best
(although not always necessary, of course). I have taken repeat GPS position
readings at the same locality in different years and for my instrument have
found the error to average about 50 meters (with a minimum of 20 and a
maximum of 100 m). This is quite adequate and represents a far smaller error
than one would have to deal with using references such as "20 km from the
village of Nachingwea in the direction of Nwanganzi (along a tortuously
winding road that may have unpredictable diversions due to flooding and
washed out bridges.........)".
Determining altitude by GPS is usually a waste of time but then the
manufacturers of GPS units generally acknowledge that.
_________________________________________
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
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