International Journal of Marine Science 2015, Vol.5, No.48: 1-7
4
Table 1 Habitat Characteristics of River Siang
Sl.
No
Habitat Cha-
racteristics
Mebo
Bodak
Ranaghat
Pasighat
Pongging
Rottang
1
Stream
Order
First Order
First Order
Second Order
Second Order
Third Order
Third Order
2
Valley
Segment
Colluvial
Colluvial
Alluvial
Alluvial
Alluvial
Alluvial
3
Microhabitat
Type
Fall with
Fast Water
Fall with
Fast Water
Cascade, Mid-
Channel Pool
Run Sheet
and Riffle
Mainly Run
Sheet and Pool
Mainly Run
Sheet and Pool
4
Cover Type Overhanging
Vegetation,
Turbulence,
Turbidity,
Undercut
bank and
Depth Cover
Overhanging
Vegetation,
Bottom Free
Boulders,
Undercut
bank and
Depth Cover
Depth Cover,
Over Hanging
Vegetation,
Bottom free
Big Boulders
Depth Cover,
Over Hanging
Vegetation,
Bottom free
Big Boulders
Overhanging
Vegetation, Depth
and Small Woody
Debris, Turbidity
and Bottom Free
Big Boulders
Overhanging
Vegetation, Depth
and Small Woody
Debris and
Turbidity
5
Substrate
Type
Gravels,
Cobbles,
Boulders
and Bed
Rocks
Cobbles, Gravels,
Bedrocks and
Boulders
Fine Sand,
Silt and Clay
Mainly Fine
Sand, Cobbles
and Gravels
Fine, Sand, Boulder
and Bedrocks
Mainly Fine
Sand, Bedrock
and Boulders
6
Riparian
Land Use
Dense Forest
and Fishing
Dense Forest
and Fishing
Mainly Human
Habitation and
Fishing
Human Habitation,
Fishing and
Industries
Human Habitation
and Agriculture
Human
Habitation
and Agriculture
7
Signs of
Erosion
Visible
Visible
Visible
Visible
Much Visible
Much Visible
8
Current
Velocity
(m/s)
5.08
5.01
2.01
1.56
0.87
0.78
9
Soil pH
6.43
6.78
7.00
7.87
7.88
7.97
10 Soil Mois-
ture %
0.32
0.32
0.41
0.42
0.36
0.32
11 Bank Full
Width (m)
55
70
150
168
280
358
12 Bank Full
Depth (m)
14
13
22
34
28
29
13 Channel
Width (m)
56.8
54
90
120
134
145
14 Channel
Depth (m)
8
11
14
26
28
22
15 Wetted
Width (m)
44-125
56-156
30-350
36-380
49-420
36-440
16 Wetted
Depth (m)
10
12
24
26
30
26
In general, it had been found that, species diversity
increases from upstream to downstream regions in the
streams. According to McConnell (1988), this was due
to the fact that, habitat diversity also increases along
the stream gradient; but, may not be in the same
direction and fashion, as species diversity. In addition,
detritus and plankton richness also seem to increase
downstream which may lead to greater diversity in the
higher trophic levels. Certain studies on African
stream fish communities (Toham and Teugels, 1997)
revealed the occurrence of distinct pattern (s) in the
longitudinal zonation of species with a sequential shift
