TROPHIC STATE AND GROWTH PARAMETERS OF Labiobarbus festivus AND Osteochilus hasseltii AT THE
TEKAK RIVER OF KENYIR LAKE, MALAYSIA
BY
AHMAD FATHI BIN MOHD SALLEH
A thesis submitted in fulfilment of the requirement for the degree of Master of Science (Bioscience)
Kulliyyah of Science
International Islamic University Malaysia
AUGUST 2018
ii
ABSTRACT
Studies on fish growth, condition, and spawning season and nutrient dynamics are important to evaluate a lake ecosystem. However, there are not adequate information on temporal nutrient dynamics, growth, condition, and spawning season of fishes in all rivers of Kenyir Lake. During this study, Labiobarbus festivus and Osteochillus hasseltii were selected to determine the growth, condition, and spawning season of fish as they are popular and important food fishes in Kenyir Lake and their captured production is gradually decreasing. In these contexts, a study was conducted on a prospective Tekak river of Kenyir Lake from Jan - Dec 2016 to (1) determine the spatio-temporal nutrient dynamics and trophic status of Tekak river, (2) investigate growth, condition and spawning season of fish, and (3) evaluate the growth parameters and spawning of L. festivus and O. hasseltii. Water quality and nutrient dynamics were studied in three sampling zones (downstream, middle and upstream) in the Tekak river. Each sampling zone was subdivided into three sampling sites. A series of water quality parameters and trophic status were determined monthly in each sampling site.
All water quality parameters significantly changed over time and in all sampling zones (except total suspended solid and water transparency) were statistically similar. Both total suspended solid and transparency decreased from upstream to downstream. A significant negative correlation (r=-0.29, p<0.01) was observed between chlorophyll-a and temperature. Trophic state significantly changed over time. It indicates that the water of the sampling area from Tekak River of Kenyir Lake was oligotrophic (low productivity) with low nutrient concentrations. To estimate growth, condition and spawning season of fishes, monthly L. festivus and O. Hasseltii samples were collected using gill-net for a period of one year (Jan – Dec 2016). A total of 2126 (male: 771, female: 1355) L. festivus and 579 (male: 239, female: 340) O. hasseltii specimens were studied in this research. A negative allometric growth (b<3.0) of L. festivus was observed from February until June, and September for female while in January, March until June, and November for male L. festivus. Positive allometric growth (b>3.0) was observed in the remaining month of both male and female L. festivus. Male O.
hasseltii, showed a negative allometric growth (b<3.0) in March and April, and a positive allometric growth (b>3.0) in January, March, August, October and November. Female O. hasseltii showed positive allometric growth (b>3.0) in all months except January, April, and July. Overall higher mean condition factor was observed in smaller compared to larger fish of both sexes. Both fishes showed spawning season from Sep-Feb with the peak of spawning for L. festivus was in November and December and for O. hasseltii the peak of spawning was in October and November (Female) and August (Male). The results of this study are useful for regular ecological monitoring and conservation of the lake. In this case, a careful monitoring is highly recommended to prevent spreading of unwanted materials in this lake. However, it can be concluded that the outcome of this study can be applied by the relevant lake authorities for the sustainable development of food fishes and endangered fishes in Kenyir Lake.
iii
ةصلاخ ثحبلا
ةسارد نإ كاسملأا ونم
فورظو مساومو اهراثكتسا ةمهم اهتيذغت تايكيمانيدو
تايرحبلل يئيبلا ماظنلا مييقت في .
عمو
كلذ هنإف و ،ةينمزلا تايذغلما تايكيمانيد نع ةيفاك تامولعم دجوت لا لا
كاسملأا ونم نع فورظو
في اهرثاكت مساومو
كاسمأ رايتخا تم ةساردلا هذه في .يرينيك ةيربح رانهأ عيجم
Labiobarbus festivus
و
Osteochillus hasseltii
ونم ديدحتل فورظو
مساومو
راثكسا يرينيك ةيربح في ةيكلاهتسلإا كاسملأا مهأ نم انهوكو اهتيبعشل ارظن كاسملأا ،
في ييجردتلا ضافنخلال ارظن بسن
ذه في .اهدايطصا ا
برمسيد لىإ رياني نم يرينيك ةيربح في بصي يذلا كاكيت رنه ىلع ةسارد ءارجإ تم قايسلا نم
ماع
2016 فادهلأا قيقتح لجأ نم ةيتلآا
( : 1 ةينمزلا تايذغلما تايكيمانيد ديدتح ) و
رنه في ةيذغتلا ةلاحو ةيناكلما
( ،كاكيت 2 ققحتلا ) نم
ونم فورظو مساومو اثكتسا ر ( و ،كاسملأا 3
ومنلا تارشؤم مييقت ) راثكتسلااو
كاسملأ
L. festivus
و
O. hasseltii
. طسولاو رهنلا ىرمج هاتجا في( تانيعلا ذخلأ قطانم ثلاث في تايذغلما تايكيمانيدو هايلما ةيعون ةسارد تتم
اوم ةثلاث لىإ تانيعلا ذخأ قطانم نم ةقطنم لك ميسقت تم .كاكيت رنه في )عبنلماو تانيعلا ذخلأ عق
. ةلسلس ديدتح تم
هايلما ةدوج يرياعم نم فورظو
تانيعلا ذخأ عقاوم نم عقوم لك في ةيذغتلا تقولا روربم .ايرهش
نم تانيعلا ذخأ تم
لظ في عقاولما عيجم يربك لكشب هايلما ةدوج تارشؤم
ادع ام ، ةيفافشو ةقلاعلا ةبلصلا داولما
ةبهاشتم تناكف )ءالما
.ايئاصحإ نخا
بصلما لىإ عبنلما نم ةيفافشلاو ةقلاعلا ةبلصلا داولما عوممج نم لك ضف .
( يربك بيلس طابترا ظحول
r=-0.29,
p<0.01
ةقطنم هايم نأ لىإ كلذ يرشي .تقولا روربم يربك لكشب ةيئاذغلا ةلالحا تيرغتو ،ةرارلحا ةجردو افلأ ليفورولكلا ينب ) يرينيك ةيربح في كاكيت رنه نم تانيعلا ذخأ
.تايذغلما نم ةضفخنم زيكاترب )ةيجاتنلإا ةضفخنم( ةميقلا ةليلق تناك
مساومو فورظلاو ومنلا تايوتسم ديدحتل رثاكت
لأا كاسم . كاسملأ تانيع عجم تم
L. festivus
و
O. hasseltii
تاكبشلا نم ايرهش
رياني( ةدحاو ةنس ةدلم ةيموشيلخا -
ماعل برمسيد 2016
ةسارد تتم .) 2126
ن نم ةكسم عو
L. festivus
:روكذ(
771 ،
:ىثنأ 1355 ) و ، 579 عون نم ةكسم
O. hasseltii
:روكذ(
239 :ىثنأ ، 340 بيلس ونم لدعم ظحول .)
(b <3.0)
كاسمأ في
L.
festivus
كاسمأ روكذل برمفونو وينوي تىح سرامو رياني في امنيب ،ثانلإل برمتبسو وينوي تىح ريابرف نم
L. festivus
دوجو ظحول .
بجوم ونم لدعم
(b <3.0)
هشلا في و يقبتلما ر ة ثانإو روكذ في
L. festivus
كاسمأ روكذ رهظأ .
O. hasseltii
لدعم ب( بيلس ونم
<
3.0 >ب( بيايجإ ونم لدعمو ،ليربأو سرام في ) 3.0
ثانإ ترهظأ .برمفونو ربوتكأو سطسغأو سرامو رياني في )
كاسمأ
O. hasseltii
بيايجإ ونم لدعم
(b> 3.0)
فورظلا لماعم طسوتم نأ ظحول .ويلويو ليربأو رياني ءانثتساب روهشلا عيجم في
ناك ىلعأ لكشب ماع ينسنلجا لاك نم ةيربكلا كاسملأاب ةنراقم .
ل رثاكتلا مسوم ناك كاسملأا نم ينعونلا لاك
نم
يدو برمفون في راثكتسلاا ةورذ تناك ثيح ريابرف لىإ برمتبس .سطسغأ تىح سرام للاخ ةحارلا ةلحرم تناكو برمس
عونل ةبسنلاب امأ
O. hasseltii
أدب دقف ( برمفونو ربوتكأ في تناك راثكتسلاا ةورذو ريابرف تىح برمتبس في راثكتسلاا ل
)ثانلإ
( سطسغأو لل
كذ ور ) حصني .ةيرحبلا ىلع ظافحللو مظتنلما يئيبلا دصرلل ةديفم ةساردلا هذه جئاتن برتعت . ةلالحا هذه في
اماتخ .ةيرحبلا هذه في اهيف بوغرلما يرغ داولما راشتنا عنلم ةقيقدلا ةبقارلما قيبطتب ناكملإاب ،
ةساردلا هذه جئاتن نأ لوقلا
.يرينيك ةيربح في ضارقنلااب ةددهلما كاسملأاو ةيكلاهتسلاا كاسملأل ةرمتسلما ةيمنتلل تاطلسلا لبق نم اهقيبطت نكيم
iv
APPROVAL PAGE
I certify that I have supervised and read this study and that in my opinion, it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a thesis for the degree of Master of Science (Bioscience)
………….………
Mohammad Mustafizur Rahman Supervisor
………
Kamaruzzaman Yunus Co-Supervisor
I certify that I have read this study and that in my opinion it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a thesis for the degree of Master of Science (Bioscience)
………
Ahmed Jalal Khan Chowdhury Internal Examiner
………
Abu Hena Mustafa Kamal External Examiner
This thesis was submitted to the Department of Biotechnology and is accepted as a fulfilment for the degree of Master of Science (Bioscience)
….………..
Mardiana Mohd Ashaari
Head, Department of Biotechnology This thesis was submitted to the Kulliyyah of Science and is accepted as a fulfilment of the requirement for the degree of Master of Science (Bioscience)
…..……….
Shafida Abdul Hamid Dean, Kulliyyah of Science
v
DECLARATION
I hereby declare that this thesis is the result of my own investigations, except where otherwise stated. I also declare that it has not been previously or concurrently submitted as a whole for any other degree at IIUM or other institutions.
Ahmad Fathi Bin Mohd Salleh
Signature ……… Date ……….
vi
INTERNATIONAL ISLAMIC UNIVERSITY MALAYSIA
DECLARATION OF COPYRIGHT AND AFFIRMATION OF FAIR USE OF UNPUBLISHED RESEARCH
TROPHIC STATE AND GROWTH PARAMETERS OF L. festivus AND O. hasseltii AT THE TEKAK RIVER OF KENYIR LAKE,
MALAYSIA
I declare that the copyright holders of this thesis are jointly owned by the student and IIUM.
Copyright© 2018 Ahmad Fathi Bin Mohd Salleh and International Islamic University Malaysia. All rights reserved.
No part of this unpublished research may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise without prior written permission of the copyright holder except as provided below
1. Any material contained in or derived from this unpublished research may be used by others in their writing with due acknowledgement.
2. IIUM or its library will have the right to make and transmit copies (print or electronic) for institutional and academic purposes.
3. The IIUM library will have the right to make, store in a retrieved system and supply copies of this unpublished research if requested by other universities and research libraries.
By signing this form, I acknowledged that I have read and understand the IIUM Intellectual Property Right and Commercialization policy.
Affirmed by Ahmad Fathi Bin Mohd Salleh
……… ………
Signature Date
vii
ACKNOWLEDGEMENTS
Alhamdulillah, all praise to Allah S.W.T, the Most Merciful and the Most Gracious for all His blessing. Only by His guidance, strength, grace, and mercy that the completion of this thesis has come to its successful.
There have been many people who have walked alongside me during previous years. They have guided me, placed opportunities in front, and showed me the doors that might be useful to open. I am very grateful to my supervisors Assoc. Prof. Dr.
Mohammad Mustafizur Rahman and Prof. Dr. Kamaruzzaman Yunus for their technical guidance and encouraging association through the period of my research in work in IIUM.
I would also like to thank both my parents for their full support during those tough years. Their inspiration and prayers always with me in spite of being far away.
My wife, Athirah Nur whom is very passionate and supportive in everything that I do – without her constant mental support this work might not come into this shape. For my parents and in-laws, thanks for their timeless support and prayers.
I am thankful to my colleagues in Kulliyyah of Science, IIUM for providing a congenial working atmosphere in the laboratory and the post-graduate lounge. I am particularly thankful to Br. Mohd Haikal Izzuddin, Br. Sakib Khan, Br. Azam Amiruddin, Br. Khairul Muttaqin, Br. Hizri, Br. Hazrin, Br. Shaqif, Br. Shahrain, Sr.
Siti Fatimah, Sr. Ainatul, Sr. Syazila Ramli, Sr. Afifah, Sr. Maryam, Sr. Najatul, and many more.
viii
TABLE OF CONTENTS
Abstract………..……… …….. ii
Abstract in Arabic ………..……….………….. …….. iii
Approval Page………...……….………… ……... iv
Declaration………...……….……… v
Copyright Page……….………….. ……... vi
Acknowledgement……….……… vii
Table of Contents……….……….…….………… ……... viii
List of Tables……….…… ……... x
List of Figures………..…………...……….. …….. xi
List of Equations…………...……… …….. xiii
List of Symbols………...………..… …….. xiv
List of Abbreviations……….……… xv
CHAPTER ONE: INTRODUCTION……….. 1
1.1 Research Background……….……… 1
1.2 Problem Statement……….…. …….. 3
1.3 Research Hypothesis…………..……….… …….. 4
1.4 Research Objective…………..………..…. …….. 4
CHAPTER TWO: LITERATURE REVIEW………...………… …….. 5
2.1 Lake and Rivers..……… …….. 5
2.2 Kenyir Lake…..………..………….... …….. 7
2.3 Water Quality of Rivers..……… …….. 8
2.3.1 Temperature..……….. …….. 8
2.3.2 Dissolved Oxygen………..……. …….. 10
2.3.3 pH………...………. …….. 12
2.3.4 Water Transparency……….……....…... …….. 16
2.3.5 Total Suspended Solid (TSS)……….………. …….. 18
2.3.6 Ammonia………..…………..……. …….. 21
2.3.7 Nitrate and Nitrite……….……….…..…….. 23
2.3.8 Phosphate……….………..…. ……... 25
2.3.9 Silica……….……….……. ……... 27
2.3.10 Chlorophyll-α……….…. ……... 28
2.4 Trophic State of Rivers….………. ……... 31
2.5 Effects of Monsoon on Health, Growth, Spawning of Fish Growth….. 33
2.5.1 Labiobarbus festivus………..…. ……... 33
2.5.2 Osteochillus hasseltii……….……….. ……... 35
2.5.3 Growth co-efficient (B-Value)……….………... ……... 37
2.5.4 Condition Factor (K-Value)………...………. ……... 39
2.5.5 Spawning Season……… 41
2.5.6 Gonadosomatic Indexes………... 42
2.5.7 Hepatosomatic Indexes………...……….……... 44
ix
CHAPTER THREE: MATERIALS AND METHODS………... 46
3.1 Study Sites…..……… 46
3.2 Determination of Water Quality and Trophic State………...…………. 52
3.3 Growth Parameters Determination and Spawning Season of Fish……. 54
3.4 Statistical Analysis of Data………...……….. 57
CHAPTER FOUR: RESULTS AND DISCUSSION…………...………... 58
4.1 Water Quality and Trophic State……… 58
4.2 Fish Growth Parameters and Spawning Season………..……… 69
4.2.1 Labiobarbus festivus……….……… 69
4.2.2 Osteochillus hasseltii………..…….……….. 79
CHAPTER FIVE: CONCLUSION AND RECOMMENDATION………. 89
5.1 Conclusion………..……… 89
5.2 Recommendation……… 90
REFERENCES………..………... 91
APPENDIX………... 120
x
LIST OF TABLES
Table No. Page No.
2.4.1 Application of TRIX index have been found in several studies of different localities.
32 2.5.1 Among L. festivus examined by Roberts (1993) 35 2.5.2 Reported a and b values for various fish species in
different localities
38
3.1.1 Sampling site coordinate 47
4.1.1 Effects of month, zone and their interaction on various water quality parameters and trophic state (TRIX index) at the Tekak river of Kenyir Lake based on a one-way repeated-measures ANOVA.
58
4.1.2 Monthly variations of various water quality parameters and TRIX index at the Tekak river of Kenyir Lake based on Tukey test
60
4.2.1 Monthly relative abundance of male and female of Labiobarbus festivus at the Tekak river of Kenyir Lake
70
4.2.2 Monthly relative growth coefficient of male and female of Labiobarbus festivus at the Tekak river of Kenyir Lake
71 4.2.3 Monthly relative abundance of male and female in
Osteochillus hasseltii population at the Tekak river of Kenyir Lake
80
4.2.4 Relative growth coefficient of male and female Osteochillus hasseltii in different sampling month
81
xi
LIST OF FIGURES
Figure No. Page No.
3.1.1 Map showing the location of sampling zones at the Tekak river of Kenyir Lake.
47
3.1.2 Sampling site: Zone A, Station 1 (A1) 48
3.1.3 Sampling site: Zone A, Station 2 (A2) 48
3.1.4 Sampling site: Zone A, Station 3 (A3) 49
3.1.5 Sampling site: Zone B, Station 4 (B4) 49
3.1.6 Sampling site: Zone B, Station 5 (B5) 50
3.1.7 Sampling site: Zone B, Station 6 (B6) 50
3.1.8 Sampling site: Zone C, Station 7 (C7) 51
3.1.9 Sampling site: Zone C, Station 8 (C8) 51
3.1.10 Sampling site: Zone C, Station 9 (C9) 52
3.2.1 Water Quality Parameter sampling method. 53
3.3.1 Gill net used for fish sampling. 55
3.3.2 Picture of Labiobarbus festivus and Osteochilus hasseltii 55 4.1.1 Interaction effect between month and zone on water
temperature at the Tekak river of Kenyir Lake.
61 4.1.2 Interaction effect between month and zone on water pH at
the Tekak river of Kenyir Lake.
62 4.1.3 Interaction effect of month and zone on water dissolved
oxygen concentration at the Tekak river of Kenyir Lake.
63 4.1.4 Spatial variation of water transparency at the Tekak river of
Kenyir Lake.
64 4.1.5 Interaction effect of month and zone on water transparency
at the Tekak river of Kenyir Lake.
65 4.1.6 Interaction effect of month and zone on silica concentration
at the Tekak river of Kenyir Lake.
66 4.2.1 Monthly mean K-Value of male Labiobarbus festivus. 74
xii
4.2.2 Monthly mean K-Value of female Labiobarbus festivus.
Data are mean and standard error (±SE).
75 4.2.3 Monthly mean gonadosomatic indexes of male Labiobarbus
festivus. Data are mean and standard error (±SE).
76 4.2.4 Monthly mean gonadosomatic indexes of female
Labiobarbus festivus.
76 4.2.5 Monthly mean hepatosomatic indexes of male Labiobarbus
festivus.
77 4.2.6 Monthly mean hepatosomatic indexes of female
Labiobarbus festivus.
78 4.2.7 Monthly mean K-Value of male Osteochilus hasseltii. 83 4.2.8 Monthly mean K-Value of female Osteochilus hasseltii. 84 4.2.9 Monthly mean gonadosomatic indexes of male Osteochilus
hasseltii.
86 4.2.10 Monthly mean gonadosomatic indexes of female Osteochilus
hasseltii.
86 4.2.11 Monthly mean hepatosomatic indexes of male Osteochilus
hasseltii male.
87 4.2.12 Monthly mean hepatosomatic indexes of female Osteochilus
hasseltii.
88
xiii
LIST OF EQUATIONS
Equation 1 Equilibrium reaction of ammonia in water Equation 2 Ammonium ions equilibrium
Equation 3 Boyd’s chlorophyll-α concentration Equation 4 Calculation of the TRIX Index Equation 5 Length-weight relationship of fish Equation 6 Linear regression on natural logarithms Equation 7 Fulton’s condition factor (K)
Equation 8 Calculation of the gonadosomatic index (GSI) Equation 9 Calculation of the hepatosomatic index (HSI)
xiv
LIST OF SYMBOLS
°C Degree Celsius
% Percentage µ Micro m Meters ml Milliliters cm Centimeters kg Kilogram g Grams mg Milligram K Condition factor Km Mean condition factor a Constant (intercept at y-axis) b Regression coefficient R2 Coefficient of determination χ2 Chi square
p Probability
® Registered trademark
™ Trademark n Numbers
xv
LIST OF ABBREVIATIONS
RM Ringgit Malaysia
KETENGAH Lembaga Kemajuan Terengganu Tengah GSI Gonadosomatic Index
HSI Hepatosomatic Index SL Standard Length
FL Fork Length
TL Total Length
BW Body Weight
GW Gonad Weight
Log Logarithm
ANOVA Analysis of Variance ANCOVA Analysis of Covariance
FAO Food and Agricultural Organization HCl Hydrochloric acid
EPA United States Environmental Protection Agency USGS United Stated Geological Survey
WHO World Health Organization MCL Maximum Contaminant Level
NHDES New Hampshire Department of Environmental Services NOAA National Oceanic and Atmospheric Administration FWRI Fish and Wildlife Research Institute
MDEQ Michigan Department of Environmental Quality
1
CHAPTER ONE INTRODUCTION
1.1 RESEARCH BACKGROUND
Lakes play important roles as a natural wetland ecosystem. Kenyir Lake is the largest (surface area about 36,900 ha) man-made lake in Malaysia. The lake is located at latitude 5o10′53′′ north and longitude 102o45′1′′ east and at altitude 178 m. The lake was built without pre-clearing and lies within a thick rainforest region. This lake was initially inundated in 1986 for hydroelectrical power supply and receiving water inputs from its main river, which is the Terengganu river.
Although this lake was developed for hydroelectric power, presently it is very important for livelihoods of many rural communities around the lake. Many inhabitants including aborigine communities near this lake are directly or indirectly dependent for fishing in this lake. Beside these, it is known as a paradise for recreational fishing activities especially for anglers.
Presently, fish population in Kenyir Lake is decreasing gradually. However, declining fish population in the Kenyir Lake is an increasing problem that threatens the lake ecosystem and the livelihood of rural communities around the lake. Fish and other aquatic organisms show a unique and strong dynamics but is relatively stable inter-annually (David et al., 2005). These special traits and dynamics of lake organisms depend on the characteristics of the lake. The organic and inorganic nutrients have a great impact on abiotic and biotic components of the lake ecosystems.
However, various nutrients greatly influence abundance, composition and size structure of lake communities including fishes (Blaber, 2000). The nutrients status of lake water is greatly influence by time of the year.
2
Kenyir Lake is connected with many rivers which originated from mountain and forest. These rivers bring considerable amount of land based organic and inorganic nutrients through river run off. Tekak river is one of the important river located Tekak river of lake. This river originated from a thick rainforest. However, information about the organic and inorganic nutrients at the Tekak river of the lake particularly in the Tekak river is still lacking. Such information is very important to understand the ecological monitoring and proper management (Luz-Agostinho et al., 2009).
Apart from understanding ecological sustainability, quality and quantity of nutrients are directly related to the lake productivity. There is also debates that fish production of Kenyir Lake might be affected due to low productivity of this lake.
However, nothing is known regarding the productivity of Kenyir Lake particularly in the Tekak river. Such information is crucial to prepare management policy for the sustainability of the lake ecosystem (Primpas and Karydis, 2011; Salas et al., 2008). In river and lake ecosystem, fish are the most important group of organisms, and play important roles in nutrient cycling and energy flow (Zhao et al, 2018). Fish communities are effective ecosystem indicators as they are relatively easy to identify (Zhao et al., 2018) and their position at the top of the food web help to provide an integrated view if the environment (Wu et al, 2014).
Studies of lakes provided some of the early indications of the effects on ecosystem structure and function and the consequences for ecosystem services resulting from the current climate change, adding to the changes by the already substantial human impact (Jeppesen et al., 2014). Understanding the growth parameters of fish is also important to understand the health of an ecosystem (Antony et al. 2014). However, growth and condition of fish might be influenced temporally
3
but the information about the trend of changing fish growth parameters over time is unknown.
1.2 PROBLEM STATEMENTS
Kenyir Lake is connected with several rivers and rainforests, which greatly influence the various water quality parameters of lake (Wetzel, 1990). Understanding the temporal status of water quality is important for ecological monitoring as well as proper management of the lake. Unfortunately, such information is lacking in Kenyir Lake particularly at the Tekak river of Kenyir Lake. Published information indicates that organic matter content in the soil of rainforest is very low as most of the soil nutrients are uptaken by densely populated various rainforest trees. Therefore, water of rainforest lakes is generally low productive. The increased entry of nutrients into the water bodies due to human activities accelerates the growth of algae and aquatic plants which is referred to as cultural eutrophication (Khorasani et al., 2018). A large portion of littoral area in Kenyir Lakes is exposed to sun as a consequence of huge contrast water level during monsoon and dry season and this could give impact on the flora and fauna of the lake (Rouf et al., 2008).
On the other hand, lakes which are connected with river are productive as rivers bring a lot of nutrients into the lake. Rivers may bring organic and inorganic nutrients and pollutants and influence water quality of the lake ecosystem. This may affect the biotic components specially fish communities of the lake ecosystems (Rahman and Verdegem, 2007). However, it is very difficult to understand the combine effects of rainforest and rivers on the productively of lake. As Kenyir Lake is connected with both rainforests and rivers, the information about the combine effects on lake productivity would be very useful for understanding lake ecosystem and the
4
status of various aquatic community particularly fishes. To date, there is no published information on the productivity status of Kenyir Lake productivity.
Presently, many Malaysian think that growth and production of fish in Kenyir Lake are decreasing (News Straits Times, 2017). Unfortunately, reliability regarding information on fish growth and production is questionable as the information was not yielded from any research. Therefore, research on population parameters of fishes is needed for the proper management of Kenyir Lake. For example, understanding spawning season of fish may lead to impose rules and to save brood fishes for sustainable fish production.
1.3 RESEARCH HYPOTHESIS
Trophic state and fish growth parameters at the Tekak river of Kenyir Lake might be changed over time throughout the year in different zones of the river.
1.4 RESEARCH OBJECTIVE
1. To determine the spatio-temporal variation of nutrient dynamics at the Tekak river of Kenyir Lake
2. To investigate the temporal trophic state at the Tekak river of Kenyir Lake 3. To evaluate the growth parameters and spawning of Labiobarbus festivus
and Osteochillus hasseltii from Kenyir Lake
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CHAPTER TWO LITERATURE REVIEW
2.1 LAKE AND RIVERS
Lake has been stratified into two layers that composed by the upper, warmer epilimnion and the underlying water mass of cool, dense water, namely hypolimnion.
The stratum between the two layers, characterized by a steep thermal gradient, is known as the thermocline (Brṏnmark and Hansson, 2005). The temporal pattern in temperature, including formation of the thermocline, is the most important physical factor that determines the structure and function of the lake, and thus can dramatically affect the environment of the lake biota. This event thereby, gives an opportunity to many freshwater organisms to change their thermal surroundings by moving to a different microhabitat like diel vertical migration as displayed by many groups of organisms such as phytoplankton, zooplankton, and fish. Migrating organisms typically spend their days in the cold hypolimnion and move up into the warmer epilimnion only during the night (Brṏnmark and Hansson, 2005). Notably, this movement would help to minimize body metabolism, reduce predation by visually orienting predators, and optimize the organisms’ digestion rate.
There are several conditions that constitute the types of lake based on the production and chemical contents. Wetzel (2001) differentiates lake types based upon production of organic matter by phytoplankton, and primary physical and chemical determinants of that production. While, Naumann (1929) has previously proposed that types of lakes can be categorized into oligotrophic, eutrophic, acidotrophic, alkalitrophic, argillotrophic, sidetrophic and dystrophic types. Oligotrophy lakes have
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low production which are associated with low phosphorus and nitrogen. Eutrophy lakes are highly productive and associated with high phosphorus and nitrogen content.
Meanwhile, acidotrophy lakes showed low production and are linked with low phosphorus and nitrogen, besides having pH value less than 5.5. Alkalitrophy refers to high productivity and is associated with high calcium concentrations. Argillotrophy signifies low productivity and is associated with high clay turbidity. Siderotrophy indicates for low production and is related with high iron content. Lastly, dystrophy is referring to low productivity and associated with high humic color. According to Thienmann (1921), the dystrophic lake type shows low level of phosphorus and nitrogen level but moderate to high humic organic content.
The growth and health of organisms in river and lake ecosystems are always determined by water quality. According to De Jonge and Postma (1974), the high productivity of a river or lake is a result of rich food supply, which is dependent on the concentration of organic matter and primary production which is influenced by the nutrients availability. A relative change in the environmental condition of river and lake occurs in a year time. During rainy season, heavy rainfalls cause the washout of sediment, nutrients, and minerals into river and lake. Washout from the upstream alters the concentration of many dissolved matter and slightly modifies the physicochemical condition of the water. pH, temperature, and turbidity are several factors that will be affected by the washout. Rainy season introduces increased freshwater flow into the river, thus alters the concentration of soluble matter besides slightly modifies the water temperature.
The main activity in lakes and reservoirs in Malaysia is, and always has been, fishing. In general, the fish stocks are degrading and a concerted effort is required to maintain exploitable resources at a sustainable level. Therefore, the fisheries and the
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fish resources of the lakes and reservoirs in Malaysia should be carefully maintained (Ambak and Jalal, 2006). According to Sharip and Zakaria (2007), a rapid pace of development surrounding many of the lake catchments in Malaysia has had significant effects on the quality of the water body.
Sharip et al. (2014) have conducted their studies to verify the water quality status and trophic state of 15 major lakes and reservoirs in Malaysia. Their findings indicated that all of the lakes have shown eutrophic in nature, meaning they were nutrient‐rich, they could experience algae blooms or macrophyte problems, and they were likely to exhibit poor water quality. Sustainable management measures and strategies are suggested to address the eutrophication problems of Malaysian lakes and reservoirs, with the national responses on lake and reservoir management also being discussed. (Sharip et al., 2014).
2.2 KENYIR LAKE
Kenyir Lake is a reservoir constructed as a saddle dam from Gawi Dam in the north, the Jenagor Dam in the south-east and several smaller dams. These dams blocked the water flow from more than 13 thousand rivers and tributaries. Since this reservoir resembles the appearance of a lake, it is also known as a man-made lake. Jorgensen et al. (2005) described that both natural lakes and reservoirs are considered as lakes. This is because they share many similarities in terms of their features. The ecosystem of man-made lake differs from natural lake and is changing over time. Wind-induced turbulence plays a major role in mixing of the water column in the lake. Protection of lakes is essential for animal and human lives as lakes serve as the habitat for fish, source of food and income for many people.
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The construction of reservoirs for water storage will likely become a common method to secure irrigation for crops, with negative consequences for biodiversity and water quality of previously running fresh water (Jeppesen et al., 2014). Therefore, protection of lakes could contribute to the maintenance of freshwater resource supply besides maintaining the balance of nutrients and the life cycle of animals, plants, and microorganisms. Previously, several studies have been conducted mostly on fish diversity, feeding behaviour, water quality, fish growth, fish community, condition factor, recreational fishing and ecotourism, cage aquaculture and fish diseases, and lake biodiversity at different rivers in Kenyir Lake (Yusoff et al., 1994; Ambak and Jalal, 1998; Zakaria et al., 2000; Kamaruddin et al., 2011, 2012; Najiah et al., 2012;
and Aznan et al., 2017). Nevertheless, there was no study has been conducted in Tekak river of Kenyir Lake which is one of the potential rivers in Kenyir Lake facilitates massive infrastructure for ecotourism activities.
2.3 WATER QUALITY OF RIVERS 2.3.1 Temperature
Temperature is one of the most crucial components to consider when evaluating water quality. This is due to the fact that temperature can influence several other parameters and can change the physical and chemical attributes of water. For many fish populations density-dependent somatic growth in adults is a key regulatory process and the effects of which are one of the best-established forms of density dependence.
Density-independent factors such as temperature, water clarity, water level, any many more play major roles in the somatic growth of fish (Matthias et al., 2017).
With this in measure, water temperature should be taken into account when determining (Wilde, 2006):
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– Metabolic rates and photosynthesis production – Compound toxicity
– Dissolved oxygen and other dissolved gas concentrations – Conductivity and salinity
– Oxidation reduction potential (ORP) – pH
– Water Density
Metabolic rates and biological activity of most aquatic organisms can be altered by water temperature (Wetzel, 2001). Apart from potentially leaving harmful effect on metabolic activity of aquatic organisms, temperature can also give rise to the chosen habitats of particular category of aquatic life either directly or indirectly (EPA, 2012). Some fishes like trout or salmon favour colder streams, while in opposite, plant species particularly aquatic plants developed in warmer temperatures (EPA, 2012).
Most aquatic animals and plant organisms outlast in a certain range of water temperatures, and very few of them can withstand extreme modifications in temperature. Tolerance and needs for optimum temperature also differ for various species of fish (Davis and McCuen, 2005).
According to Tomar (1999), temperature is one of the most essential parameters in water and wastewater system as it has significant impact on growth and ecological life. Temperature also has great effects on the solubility of gases such as oxygen in water. Husna et al., (2006) stated that temperature can be measured in situ as it could gradually reach the same temperature as the surrounding water.
Furthermore, it is pertinent to note that, high light intensity might also indirectly affect the nutrient concentrations during summer in water body. According to Badran (2001), this is because nutrients might be decreased as aquatic life such as green plant
