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These tropical fish can come from any of the three big lakes of Eastern Africa - Lake Tanganyika, Lake Victoria and Lake Malawi. The environment in these lakes is alkaline and rocky and though many aquarists say that these freshwater fish do adapt to a large variation of pH, it is best to meet the specific requirements of these creatures, which depends greatly upon the lake from which they come.
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These fishes are very territorial.
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May 03, 11
How Suspended Organic Sediment Affects Turbidity and Fish Feeding
Behavior
By
Mary Ann Madej
November 2004
in this issue:
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Above:
A biologist makes
underwater observations of fish feeding behavior during low-turbidity conditions
in northern coastal California. Photograph by
Samantha Hadden
. [
larger version
]
Salmon need clear water to see their prey, such as aquatic insects and other
macroinvertebrates; yet many of these same prey feed on suspended organic
particles that cloud the water. Salmon health, then, depends on a balance
between water clarity and the turbidity caused by suspended organic particles
that sustain their prey. A team of researchers from the U.S. Geological Survey
(USGS) and Humboldt State University are taking a close look at this balance,
partly in response to concerns about coastal streams whose water clarity is
becoming increasingly impaired by such land uses as grazing, mining, timber
harvest, and road construction.
Mary Ann Madej
and
Margaret
Wilzbach
of the USGS and
Kenneth Cummins
,
Samantha Hadden
, and
Colleen Ellis
of
Humboldt State University are investigating the interactions among suspended
sediment, turbidity, and salmon in northern coastal California streams and
estuaries.
Turbidity in streams and estuaries is produced by particles, both organic and
inorganic, suspended in the water column. Organic particles come from various
sources within and around steams, such as algae and leaf litter; inorganic
particles come from erosion of the surrounding hills and are washed into streams
during storms. During high streamflows triggered by storms, inorganic particles,
such as sand and silt, make up most of the suspended sediment in the turbid
water. As the flow declines, the inorganic particles settle out of the water,
and the lighter, organic particles remain. The organic particles that remain in
suspension cause low -
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