Why are there more Tropheus variants in the South end of the Lake?

[gotticgs]

why is there more fish at the bottom of the map
than the top


my first guess would be due to limited exploration due to pirates and rebels?

is that right?

[CichlidFan]

Good Question, there could be several reasons....the main one might have something to do with choice habitat...maybe food resources..??

CF

[geoff_tropheus]

The southern end of the lake is the most explored areas because Tanzania and Zambia are very stable areas when compared to Congo and Burundi.

Tanzania as corrupt and poor as it is, has been pretty stable since the 80's. Zambia has been stable and much less corrupt for a much longer time.

Congo (in revolution its entire existance) and Burundi (civil war ended in 2005) may never really stabilize so that a much more detailed exploration can occur.

[J-WS6]

Couldn't have said it better myself.

[myjohnson]

I agree with geoff's point completely, and there may also be another reason. I hypothiese that both polictical and ecolocial reasons effect the lower amounts of different color morphs founds in the northern part of the lake.

The Aqualog states, lineage 1 "formerly inhabited the northernmost part of the lake, which today is covered with sediment from the Ruzizi River. In the past the lake is thought to have extended north almost to where Lake Kivu (which did not exist) lies today."

"The rocky biotopes that existed then have subsequently been buried beneath deposits of sediments carried by the Ruzizi River and the populations that lived there have disappeared. These ancient lineages have today been forced south by the Ruzizi sediment. Many of their biotopes are becoming increasingly silted up, and some of the numbers have already significantly deceased." p. 36

The tropheus have to basically follow where their food is and if the sediments are covering the rocks on which their food grows they are force to move or die.