Thursday, July 5, 2012

News from the Beach by Campbell

I have been at Kande Beach, as a researcher, with the Maru Research
Center for going on 4 months now. I am in the fortunate position to
study and dive with the cichlids in their natural environment daily
and find these amazing fish more interesting with every dive. The
mating behavior of the cichlids are fascinating and I thought I would
share with you some of the interesting things we have been seeing on
the reefs around Kande Island recently.
Female Chambo (Oreochromis karongae) are often seen in loose shoals in
many areas of the lake and the females are commonly seen around the
island and on the outer reef, the females are also most commonly
caught by fisherman and males are not commonly seen (see the below photos for 
map of dive sites around Kande island and pictures of mentioned
fish). According to the literature the breeding season for chambo runs from July to
March, peaking around September and again in February.  Like other
Oreochromis, they are maternal mouthbrooders. Males dig large spawning
platforms, they construct a slightly raised bowl-shaped central
spawning cone inside the larger pit, we refer to these structures as
nests. On the dive map there is an area named 'crater nests', in this
area there are a lot of the big nests created by the male Chambo, this
area was deserted when I arrived at Kande (March), but from middle May
until late June we suddenly saw many male Chambo that moved into this
area, with fish clearly favoring specific nests. They have disappeared
again over the last 2 weeks. We are planning to construct survey
transects in this area to monitor nests and fish in this area in order
to accurately pin down the Oreochromis karongae (Chambo) mating season
in this region, this data can be used to make recommendations towards
a chambo closed season in the area.
 The small nests most commonly found near the mooring buoy (see map)
are constructed by  Aulonocara "blackfin" males. I have noticed one of
these fish building a crater nest on the back seat of the jeep wreck
(see island map). I found this interesting since the fish could not
dig a spawning platform since the area it was constructing the nest on
was solid, it could only construct the bowl shaped crater by carrying
sand on to the seat. I have seen the fish carrying sand from the
surrounding areas to the jeep. We found a couple of fish mouthbrooding
at very convenient spots for us to watch them protecting their fry
during the last week. A Nimbochromis polystigmata with fry in the jeep, 
a Tyranochromis "sp" in the dug out canoe at the outer reef transect and a
Scianochromis niassae into the small wreck at the island. I will keep you 
updated as to what is happening in the lake.





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10 comments:

  1. Nice post. I have enjoyed reading it. Thanks.

    ReplyDelete