Research Article
Ann Agric Crop Sci. 2021; 6(1): 1068.
Population Estimation of Oncorhynchus mykiss, Salmo trutta and Schizothorax plagastimous in Upper River Swat, Khyber Pakhtunkhwa, Pakistan
Khan T1, Hayat S2, Ullah F3*, Hayat H4, Ali S2, Khan S5 and Ahmad M1
1Department of Fisheries and Aquaculture, University of Veterinary & Animal Sciences, Pakistan
2Department of Livestock & Dairy Development, Khyber Pakhtunkhwa, Pakistan
3Lasbela University of Agriculture, Water and Marine Sciences, Pakistan
4Department of Pathology, University of Veterinary and Animal Sciences, Pakistan
5Department of Dairy Technology, University of Veterinary & Animal Sciences, Pakistan
*Corresponding author: Farman Ullah, Lasbela University of Agriculture, Water and Marine Sciences, Faculty of Veterinary and Animal Sciences, Uthal, Balochistan, Pakistan
Received: January 12, 2021; Accepted: February 03, 2021; Published: February 10, 2021
Abstract
This study was designed to assess the population status of Oncorhynchus mykiss (Rainbow trout), Salmo trutta (brown trout) and Schizothorax plagastimous (swati fish) in river Swat. Data were collected from four Sub- Areas (SAs) namely Madyan (SA1), Mankiyal (SA2), Kalam (SA3) and Mahoo Dhand (SA4). Fishes captured with electrofisher were identified morphologically and the wet weight and body length were determined. A total of 502 fishes were captured and identified. The highest capture (206) was recorded at SA4 whereas the lowest (64) at SA1. Similarly the highest captured specie (276) was Salmo trutta while the lowest (22) was Schizothorax plagastimous. The body length ranged from 15-36 centimeters whereas the wet weight varied from 47- 304 grams. Out of 502 fishes, 64, 104, 124 and 206 were from SA1, SA2, SA3 and SA4, respectively. The mean wet weight of Oncorhynchus mykiss, Salmo trutta and Schizothorax plagastimous 137.15g, 124.57g and 138.85g, respectively.
Keywords: Population estimation; Trout fish; Upper river swat; Electro fishing
Introduction
RIVER Swat starts from Mahoo Dhand at an elevation of about 3,000 meters, passes through the valley of Swat and flows for about 160 kilometer across the valley up to Chakdara. Total length of the river is 250 kilometers from Kalam to river Kabul near Charsadda. River Swat provides habitat for various fish species especially the trout in the upper part. The valley is mainly known for its abundant fish resources [1]. Trout belong to the group of fishes known as Salmonids. The typical coloration of rainbow trout is blue to olive green above the lateral line, a pink band along the lateral line and silver below the lateral line. Brown trout have generally some shade of brown on the back and side, fading to yellow on the belly, spots are large and black [2].
Materials and Methods
Permission from fishery department
Before starting the field work, permission was obtained from the Fishery Department, Khyber Pakhtunkhwa and a research officer of the Trout Culture & Training Center (TCTC) Madayn, Swat was deputed by the department for technical assistance & facilitating the work.
Site selection
The subareas selected for fish capturing were: Madyan, Mankiyal, Kalam, and Mahoo Dhand indicated as SA1, SA2, SA3, SA4, respectively.
Fish capturing
Fishes were captured through electrofisher, a common scientific survey method used to sample fish populations to determine abundance, density, and species composition [3-5]. Electrofishing caused no permanent harm to fish and fish usually returned to their natural state in as little as two minutes after being stunned. The captured fishes were identified on the basis of morphological characteristics.
Statistical analysis
The data were analysed by Analysis of Variance (ANOVA) through SAS 9.1 statistical software and Duncan’s Multiple Range Test (DMRT) was applied to compare means [6].
Results and Discussion
The studies were conducted at four Sub-Areas (SAs) of the upper river Swat viz: Madyan, Mankiyal, Kalam and Mahoo Dhand denoted by short words of SA1, SA2, SA3 and SA4, respectively. The details of captured fishes from each sub-area are given as under.
Subarea madyan (SA1)
From SA1, 64 fishes (56 S. plagastimous and 8 O. mykiss) were captured. Mean wet weight of S. plagastimous and O. mykiss was as recorded as 121.85±46.24 g and 130.25±45.02 g whereas mean body length of S. plagastimous and O. mykiss was as recorded as was recorded as 20.73±3.80 cm and 21.75±2.5 cm, respectively. The relative abundance of S. plagastimous and O. mykiss was 87.5 % and 12.65 %, respectively (Table 1).
Sub-area
Species
Captured fishes
Length (cm±SD)
Weight (gm±SD)
Abund-ance
Mad-yan (SA1)
O. mykiss
8
21.75±2.5
130.25±45.02
12.65%
S. plagastimous
56
20.73±3.80
121.85±46.24
87.35%
Table 1: Data of Fishes Captured At Madyan (SA3).
Subarea mankiyal (SA2)
From SA2, 106 fishes (84 S. trutta, 14 S. plagastimous and 8 O. mykiss) were captured. Mean wet weight of Salmo trutta, S. plagastimous and O. mykiss was as recorded as 117.69±64.79 g, 155.85±59.18 and 113.5±81.17 g whereas mean body length of S. trutta, S. plagastimous and O. mykiss was as recorded as was recorded as 20.84±4.60 cm, 23.42±3.50 cm and 20±5.7 cm, respectively. The relative abundance for S. trutta, S. plagastimous and O. mykiss was 79.24%, 13.20% and 7.54%, respectively (Table 2).
Site
Species
Captured fishes
Length (cm±SD)
Weight (gm±SD)
Abund-ance
Mank-iyal (SA2)
S.trutta
84
20.84±4.60
117.69±64.79
79%
O.mykiss
8
20±5.71
113.5±81.17
7.54%
S.plagastimous
14
23.42±3.50
155.85±59.18
13.20%
Table 2: Data Of Fishes Captured At Mankiyal (SA2).
Subarea kalam (SA3)
From SA3, 126 fishes (112 S. trutta and 14 O. mykiss) were captured. Mean wet weight of S. trutta and O. mykiss was as recorded as 141.80±76.44 g and 110±39.88 g whereas mean body length of S. trutta and O. mykiss was recorded as 22.85±5.44 cm and 20.83±2.78 cm, respectively. The relative abundance of S. trutta and O. mykiss was 88.89% and 11.11% (Table 3).
Sub-area
Species
Captured fishes
Length (cm±SD)
Weight (gm±SD)
Abund-ance
Kalaml (SA3)
O. mykiss
112
22.85±5.44
141.80±76
88.88%
0.44
S. plagastimous
14
20.83±2.78
110±39.88
11.11%
Table 3: Data of Fishes Captured At Kalam (SA2).
Subarea mahoo dhand (SA4)
From SA4, 206 fishes (180 S. trutta and 26 O. mykiss) were captured. Mean wet weight of S. trutta and O. mykiss was as recorded as 162.37±75.04 and 94.85±86.94 g whereas mean body length of S. trutta and O. mykiss was recorded as 24.23±5.278 cm and 26.64±2.78 cm, respectively. The relative abundance of S. trutta and O. mykiss was 87.37% and 12.62%, respectively (Table 4). The results of the present study are in line with the results of [7,8] regarding the fish diversity of river Swat. In the same way, results of [9] regarding length of the 96 trout fishes (13.0-88.4 cm) also support this study. The highest capture at SA4 is probably due to least water temperature and highest dissolved oxygen [essential for trout survival] as compared to other areas.
Sub-area
Species
Captured fishes
Length (cm±SD)
Weight (gm±SD)
Abund-ance
Mahoo Dhand (SA4)
O. mykiss
180
24.23±5.278
162.37±75.04
87%
S. plagastimous
26
26.64±6.046
194.85±86.94
12.62
Table 4: Data of fishes captured at Mahoo Dhand (SA4).
Conclusion
From the present study it is concluded that upper parts of river Swat (especially river part from Mankiyal to Mahoo Dhand) provide a rich habitat S. trutta and O. mykiss species of trout.
Acknowledgment
The authors are indebted to Mr. Jaffar Yahya, Research Officer and all the team of Government Trout Culture and Training Center (TCTC) Madyan, Swat, for their technical assistance and for supplying the facilities, equipment and time necessary to complete the field work.
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