Chapter 1-3 (with border).docx

1University of Santo Tomas College of Science PAGE

CHAPTER 1

Introduction

1.1. Background of the Study

Biological invasion is a major cause of ecosystem disruption and biodiversity loss

(Albins & Hixon, 2011). It is a global problem which has great impacts that can be of great

magnitudes (Arguelles & Zilletti, 2005). Biological invasions happen when organisms are

introduced into a new ecosystem, either intentionally or unintentionally. These organisms,

referred to as invasive species, may cause drastic changes and more often than not, damages

to the new environment they are introduced in. Loss of native biological diversity and

extinction of native populations are some of the presupposed damaging ecological

consequences of species invasions.

In a renowned Philippine lake, the Laguna de Bay, there is a growing concern on the

lake being besieged once again by another type of aquatic invasive species. Laguna de Bay is

the largest lake in the Philippines and is situated between the provinces of Laguna and Rizal.

The Philippines‘ largest inland body of freshwater is an abode of a variety of organisms

comprising its biodiversity pool.

The invasive species of the lake comprises 70 percent of the fishermen‘s catch, and is

believed to be a Chitala ornata species. The fish species is known by different names

including Clown knifefish, Spotted knifefish, and Clown featherback.

Chitala ornata invasion is the second biological invasion that took place in the lake.

The lake was previously invaded by the suckermouth catfish, or locally known as the ―janitor

fish‖. The janitor fish has no known predator, which is why they easily proliferated and


outnumbered the native fishes in Laguna Lake. Recently, another type of invasive species,

Chitala ornata, is creating havoc in the said lake. It is uncertain if the said species could have

escaped or could have been intentionally freed as a result of aquarium releases (Cinco, 2012).

The Clown knifefish Chitala ornata is characterized by its silver gray coloring, with

large spots of variable patterns above the base of its anal fin. It bears a flat and elongated

body with an arched back. Its anal fin and caudal fin are joined, giving it a long, continuous

body. Owing to its sword-like appearance, the clown knifefish is one of the most favorite

ornamental fish species of fish hobbyists. They are found in freshwater bodies in Southeast

Asian countries such as Thailand and Burma. Belonging to the Order Osteoglossiformes,

Chitala ornata species are considered one of the most primitive of the modern teleosts. The

term bonytongue describes a trait shared by all members of the Order Osteoglossiformes;

well-developed tooth-like tongue bones that bite against teeth on the roof of the mouth

(Cooke & Bruce, 2004). The Clown knifefish species are believed to be carnivores (Hargrove

& Hargrove, 2006). In their natural habitat, they are primarily piscivorous preying on other

fish species.

To date, amount of prey consumption and selection of Chitala ornata species in

Laguna de Bay have not been investigated; although local news have reported that these

fishes feed on indigenous species inhabiting in the lake, leading to a decline in the catch of

economically important fishes like tilapia and bangus (milkfish). Early efforts to assess the

density of Clown knifefish in Laguna de Bay by the Bureau of Fisheries and Aquatic

Resources (BFAR) reported that the Clown knifefish populations were rapidly increasing,

displacing the native species of the lake.


1.2. Statement of the Problem

The invasion of the predatory knifefish in Laguna de Bay is alarming. It terrorizes the

biodiversity of the once remarkable lake. It does not only spawn environmental harm, but

also of economic harm. The local fishermen have raised their concerns on the negative

effects of the invasion in their livelihood.

The rationale of the study is to determine the feeding ecology, specifically, to

examine prey selection, quantity of consumption, and the ability of Chitala ornata species to

endure starvation. Moreover, the study addresses the following specific questions:

1. Is there a relationship between prey size and selection in three size classes of

Chitala ornata?

2. What is the prey range in Chitala ornata found in Laguna de Bay?

3. How much is the food consumption per unit time in different sizes of Chitala

ornata?

4. Is there a significant difference on the prey consumption in three size classes of

Chitala ornata?

5. How much is the energy conservation in the three size classes of Chitala ornata

during periods of starvation?

6. Is there a significant difference on the conservation of energy in different sizes of

Chitala ornata during periods of starvation?


1.3. Objectives of the Study

This study will focus principally on the species of Chitala ornata, which will be

gathered from Laguna de Bay, Philippines. The feeding ecology of the said invasive species

will be studied through experiments and observations in the laboratory. Thus, this study

aims:

1. To determine the relationship between prey size and selection of Chitala ornata;

2. To determine the fish species found in Laguna de Bay that the Chitala ornata

species are eating;

3. To know the quantity of prey they consume per unit time; and

4. To determine the ability of Chitala ornata species in withstanding periods of

starvation.

1.4. Significance of the Study

The information that will be obtained by the researchers from the study will surely be

a vital and useful knowledge on the subject of feeding ecology in Chitala ornata, in addition

to the already acknowledged facts concerning the nature of the said fish species. The findings

from the experiment can be utilized by different sectors, agencies like BFAR, academic

institutions, as well as the local fishermen of Laguna de Bay. Moreover, the results of the

study will certainly be of help to the researchers and scientists who are studying Chitala

ornata, and to the future researches as well. Lastly, the study will aid in better understanding

the themes relating to ecology and biodiversity.


1.5. Scope and Limitations

The study will be focusing primarily on the feeding ecology in Chitala ornata (Clown

knifefish). It will cover the following areas of study: prey selection, consumption, and its

capacity to withstand periods of starvation. The live prey fish that will be used for the

experiments and observations on prey selection and consumption is Tilapia (Oreochromis

sp.) of various sizes. The laboratory set-ups for the experiments and observations of the study

will be assembled and accomplished at the University of Santo Tomas. It is expected that the

researchers will finish the experiment within a span of 5 months. The results and information

that will be obtained from the study may be directed to the agencies/institutions like BFAR,

to the academic community, and the fishermen of Laguna. The research does not cover any

other areas of study apart from what is stated, specifically on the subject of eradication of

these invasive species on Laguna de Bay.


CHAPTER 2

Review of Related Literature

2.1. Biological Invasion

Biological invasions are increasing on a global scale and have become an issue of

critical importance because of their real and potential impacts on both marine and freshwater

ecosystems (Heinonen & Auster, 2012). Such invasions consist of complex processes and

phases such as transportation to a new region, release or escapement in the wild, dispersal or

spread and finally, its relative impacts in its new environment. Invasive alien species are non-

native species in a new environment that have spread beyond and become abundant. Species

invasions are believed to be increasing, and are now recognized as one of the main threats to

biodiversity and one of the drivers of global change. Not only species invasions affect

biodiversity, such species may act as vectors for new diseases, reduce biological

productivity, degrade habitat structure, and alter food webs through ecological processes

such as competition and predation (Heinonen & Auster, 2012). The decrease or elimination

of native populations causes negative impacts on ecosystem functions, and even enormous

economic effects. In addition, freshwater ecosystems and fish taxa are mostly affected by

introductions. An example of such introduction of non-native species is the invasion of lion

fish Pterois volitans in the Bahamian archipelago leading to a decrease in the number of

Bahamian coral-reef fish communities. Although extinction is the most common result of

invasions, there are other ecological and evolutionary impacts of biotic homogenization that

are less understood thus, prevention and precautionary principles are of particular relevance

to invasive species (Clavero & Berthou, 2005).


Invasions on biological systems are worldwide ecological events, although their

mechanisms are still not clearly understood. Invasive species create negative impacts on

endemic species and ecosystems they are introduced in, through competitions, predations,

altering habitats, and dispersing diseases. They pose an escalating hazard to the composition

and structural aspects of natural communities across the globe. Biological invasion has been

injurious to the ecological and evolutionary integrity of natural ecosystems to a great extent,

which causesthe deterioration of the functions of the ecosystems, and recurrently causes

natural adversities. An enhanced knowledge of the origins, patterns, predictability, outcomes,

and management preferences concerning this threat to our biodiversity is a vital tool to direct

managers, policy makers, researchers, and the general public. Biological invasions cause

enormous economic losses. A statistical analysis stated that at least 137 billion dollar losses

annually from biological invasion were estimated in USA. Invasive diseases, another result

of invasions, weaken human health and can take the lives ofmany people. Biological invasion

for the most part diminishes global biodiversity, which will menace the survival

and development of the succeeding generations (Xie, et. al., 2003). There really are a number

of harmful and negative effects of biological invasions so it is necessary to examine and

make researches regarding the invasive species which cause these global invasions.

2.2. Invasive species

The Center for Invasive Species and Ecosystem Health defines the term ―invasive

species‖ as any non-native or alien biological species (including seeds, eggs, spores, or other

propagules), and whose introduction to an ecosystem causes or is likely to cause economic

harm, environmental harm, or even harm to the human health. These invasive species grow

http://europepmc.org/abstract/MED/14986391/?whatizit_url_Species=http://www.ncbi.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=9606&lvl=0

http://europepmc.org/abstract/MED/14986391/?whatizit_url_Species=http://www.ncbi.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=9606&lvl=0

http://europepmc.org/abstract/MED/14986391/?whatizit_url_go_term=http://www.ebi.ac.uk/ego/GTerm?id=GO:0007275

http://europepmc.org/abstract/MED/14986391/?whatizit_url_go_term=http://www.ebi.ac.uk/ego/GTerm?id=GO:0007275


and reproduce very fast, resulting to a major disorder to the ecosystems in which they are

present ("Invasive species 101," 2012).

The grounds of the crisis on invasive alien species are chiefly economic and thus, it

also require economic solutions. The subject on invasive alien species is gaining a high

concern for four main reasons. First, biological invasions are increasing rapidly whilst the

mechanisms and plans for eradication of these foreign species have been either inhibited or

totally failed. Second, the costs of these invasions are growing quickly owing partially to the

augmenting human population density, and to some extent, to the rising intensity of

production in genetically impoverished agricultural systems. Third, invasions are related with

a high degree of ambiguity because they both involve new interactions and for the reason that

biological invasion risks are endogenous. Lastly, the elimination and management of these

invasive species are a "weakest-link" public good. According to the Convention on

Biological Diversity (CBD), it defines invasive alien species (IAS) as organisms that are

introduced to a certain ecosystem. They now establish, grow naturally, and multiply outside

of their habitat range, and whose impacts entail significant harm on economy and even the

human community. Biological invasions make threats on societies in at times critical ways;

for instance, the spread of HIV infection in southern Africa. Economics aids in the

identification of the social causes generated by biological invasions, and therefore develop

institutions and mechanisms capable of solving them (Perrings et al., 2002). In a recent

species invasion in the Philippines, one of its inland bodies of water is invaded by an aquatic

dweller. This invasion is the second account of species invasion in the freshwater lake.


The problem on the subject of invasive species is of much interest to researchers in a

wide array of diverse fields including Biological Science, Epidemiology, Agriculture, Public

Health, Human Sciences, and other fields of Science. This topic is of great importance for it

concerns the whole world to a greater or lesser degree (Pastoret & Moutou, 2010). Academic

works and researches concerning the topic prove to be a key in better understanding the

biodiversity of the diverse ecosystems in our world; and moreover, to address the problems

generated by these invasive species.

2.3. Laguna de Bay

2.3.1. Biophysical Features

Laguna de Bay, also known as Laguna Lake, is the largest lake in the Philippines and

the second largest freshwater lake in Southeast Asia. Located on the island of Luzon, the

Laguna de Bay watershed cuts across five provinces, 66 municipalities and 9 cities including

parts of metropolitan Manila (Oledan, 2001). The lake provides livelihood to fishermen of

Laguna and Rizal provinces, and supports some 9,000 ha of fish pens and fish cages (Palma,

Diamante & Pol, 2002). In the past, humans used Laguna de Bay mainly for fishing industry,

which helps in providing an important source of livelihood for the local population. Through

the years, Laguna Lake has become an important source of water for agricultural,

commercial, and domestic use. Until the 20th

century, the lake served as a waste disposal site

for all of these human activities Thus, the lake gives important sources of livelihood for the

local communities. Through the years, Laguna Lake has become an important source of food,

water for irrigation, power supply, cooling of industrial equipments, and a source of raw


water for domestic supply. During the winter season in other parts of the world, Laguna de

Bay serves as a shelter for migratory birds and a place for food hunting.

The evolution of the lake was defined by at least three major paleosalinity shifts that

occurred over the past 6,000 years (Jaraula, 2001). The lake evolved from brackish water to a

marine and ultimately, to a freshwater by the changes in the sea level and tectonic plates. The

lake‘s water turbidity is due to the high surface area to volume of water ratio. The

Philippines’ Department of Environment and Natural Resources (DENR) classifies

Laguna de Bay as a Class C fresh surface water. Having a Class C type of water means it

is adequate for the propagation of fishes and other aquatic resources, non-contact

recreational purposes such as boating and jet skiing, and as a source of industrial water

(DENR, 1990). Being a Class C type of water body, its pH lies between 6.5-8.5, along

with nitrate and phosphate content of 10 mg/L and 0.4 mg/L, respectively (Santos-

Borja, 2006).

2.3.2. Biodiversity and Fishery

Aquaculture is an important factor in the fishery of Laguna de Bay in the Philippines.

Fish pens and net-cages covered 10% of the lake surface in the late 1990s. Aquaculture

became a very profitable lake-related business suggesting the culture of other species (e.g.,

tilapia; bighead carp , Hypopthalmichthys nobilis). A stock assessment of major fishery

resources showed the open water catch is composed of 13 species, including the shrimp

commonly found in the lake (Palma et al., 1997). Among the fish species commonly caught

were Oreochromis sp., H. nobilis., and A. manilensis. For phytoplankton, the most common


are the blue-green algae and diatoms. One study shows that the phytoplankton group in

Laguna de Bay consisted of the blue-green algae Sprirulina major and Lyngbya limnetica,

green algae Chlorella vulgaris and Pediastrum sp., and for the diatoms, Bacillariophyta

(Delima & Baldia, 2012). From May to September, abundance of phytoplankton is generally

observed. Also, alarming levels of algal blooms can be observed during these months which

are often dominated by Microcystis sp.

Laguna de Bay used to be a home for 23 freshwater fish species. However, due to the

ineffective flood control structure and destructive government-sponsored, foreign-funded

development projects around the lake, only 6 species survived. Some of the species that were

endangered include martiniko (climbing perch), igat (eel), talakitok (carynx), biyangbato

(rock goby), kansuswit (halfbreak), biyangtulog (sleeping goby), biyangputi (white goby),

buan-buan (tarpon), bulong (goby), talilong (mullet), dalag (snakehead), papalo (sneaker),

tawes (tawes), kitang (spade fish), baliga (eel goby), plasid (snakehead), and another kind of

plasid known as three spot. Presently, there are no recorded endemic species in Laguna de

Bay, probably because it is very young lake, formed 6,000 years ago. Its link to Manila Bay,

and the introduction of non-native species, also could have contributed to this phenomenon

(Santos-Borja, 2006). To date, an additional cause of the decrease in number of native

species is the invasion of another aquatic species, like the Chitala ornata or Clown knifefish.

2.4. Chitala ornata

2.4.1. Biology

The Clown knifefish (Chitala ornata) is a tropical (24°C - 28°C) freshwater fish,


under the Class Actinopterygii, Order Osteoglossiformes, and Family Notopteridae. It is an

indigenous fish of several Asian countries including Cambodia, Indonesia, Laos, Thailand,

and Vietnam; inhabiting flowing waters of large and medium-sized rivers. It is distinguished

from other members of the family by the existence of a row of large ocellated spots above the

base of the anal fin. It is a piscivorous type of fish, preying on surface-feeding fishes,

crustaceans and insects alike, with a crepuscular or nocturnal activity pattern. A mature

Clown knifefish can reach a maximum length of 100.0 cm and a maximum published weight

of 4,950 g ("Chitala ornata," 2012).

2.4.2. Ecology

Chitala ornata is known to different names: Clown featherback (English), Trey krai

(Khmer), Pa tong khuai (Lao), Pla tong krai (Thai), and Ca com (Vietnamese), among many

others. This fish is found dwelling extensively in mainland Southeast Asia. It is a

carnivorous, night-active (crepuscular) type of fish, feeding mainly on other fishes,

crustaceans, and even insects. Similar to its congenera, Chitala blanci, its spawning habitats

are established on inundated woods from March to July, with the female fish guarding the

fry. According to Smith (1945), after spawning, the female departs and the male takes in

charge in safeguarding the eggs. Chitala ornata is reported to have been migrating locally

into smaller tributaries and flooded areas during flood season and return back to the main

river channel when the flood has already subdued. A number of fisher folks have said that the

habits and spawning of Chitala ornata as well as Chitala blanci were the same on the

mainstream. Observations on the spawning habits of the two featherbacks have been made in


Loei, Paksan, Nakhon Phanom, and Ubon Ratchathani provinces in Thailand. Large

individuals of featherbacks have been standard goods at local markets throughout its range.

Chitala ornata is more commonly seen than its congenera, Chitala blanci. They are chiefly

caught by gillnets, and hook and line. Furthermore, Chitala ornata is a prominent facet in

aquarium trade (Poulsen et al., 2004).

2.4.3. Invasion in Laguna de Bay

As represented by different articles with reference to the invasive species, the

mechanism of invasion is two-fold. It may either be natural or deliberate. In the case of the

invasion of Chitala ornata in Laguna de Bay, the incursion is caused by either one of these

two: (1) the fish could have escaped or else, (2) it could have been intentionally freed. Some

sectors accept the first theory, in which the knifefish might have escaped from fish farms

during the flood generated by tropical storm Ondoy in 2009. On the other hand, others

consider the latter theory. They suppose that the propagation of Chitala ornata could have

been done by knifefish hobbyists who released the fishes in the waterways when the fishes

have grown too large to be kept on the aquariums; an idea similar to that of the proliferation

of the overtaken suckermouth catfish (commonly known as ―janitor fish‖) in the previous

years. Both fishes were known to be introduced in the Philippines as ornamental fishes

(Galvez, 2012).

2.4.4. Effects of Chitala ornata Invasion

According to an article of The Manila Times entitled ―New ‗monster‘ species out to

ruin Laguna Lake‖ published last May 19, 2012, an invasive predator known as the


―knifefish‖ is now threatening to wipe out the biodiversity of the country‘s largest lake —

Laguna de Bay. An alliance of fisher folk and stakeholders has asked the Laguna Lake

Development Authority (LLDA) to investigate what they call the ―invasion of the predators,‖

which are now spreading in a very rapid pace, preying on the different native species found

in Laguna lake. A number of groups including Pambansang Lakas ng Kilusang

Mamamalakayang Pilipinas (Pamalakaya), Save Laguna Lake Movement (SLLM) and

Anakpawis party list, have staged a fluvial protest to call the attention of the local

government to take action on the problem regarding the invasion of the knifefish.

One article from Phili ppine Daily Inquirer entitled ―Knifefish threatening native

species in Laguna Lake‖ issued on May 21, 2012, reported the consequences of the invasion

of the predator. According to Bureau of Fisheries and Aquatic Resources (BFAR), the rapid

multiplication of the invasive species is displacing the native species of the lake. The

fishermen‘s groups of Laguna de Bay have complained that their catch of native fishes

including tilapia, bangus (milkfish), martiniko, igat (eel), dalag (mudfish), biya (goby), and

ayungin (silver perch), is shrivelling, with their income threatened because the citizens were

not accustomed to eat the foreign fish. In the long run, it is not impossible that the indigenous

fishes found in Laguna de Bay will go extinct.

Because of the different negative effects resulting from the invasion of the infamous

knifefish in Laguna de Bay, different proposals for action are made to address the growing

problem. BFAR has proposed a plan of collection and harvest of the knifefish eggs in order

to impede the production of the invasive species. The objective is to get rid of the clump of

eggs, numbering to several thousands of fry, resulting to a significant decrease in the


population. This plan was based on the findings made by the agency‘s National Inland

Fisheries Technology Center, which demonstrated how knifefish could spawn naturally in the

lake and its eggs stick to the bamboo poles and stakes of fish pens and cages owned by the

local fishermen. BFAR has worked in partnership with the Laguna Lake Development

Authority (LLDA) to better address the problems plaguing the country‘s largest lake and

which affect the livelihood of the local fishermen (Salaverria, 2012).

2.5. Biodiversity

As stated earlier, one of the many dilemmas on the invasive species is undoubtedly

linked to the subject of biodiversity. For example, The International Union for the

Conservation of Nature (IUCN) has instituted the so called ―Red List of Threatened Species‖,

which is generally recognized as the most comprehensive, objective global approach for the

evaluation on the conservation status of diverse biological species. The list includes attributes

like: Extinct (EX), Extinct in the Wild (EW), Critically Endangered (CR), Endangered (EN),

Vulnerable (VU), Near Threatened (NT), Least Concern (LC), Data Deficient (DD), and Not

Evaluated (NE). Many of these biological species are threatened by the invasive species and

other human-related factors. Human beings are, and always have been, the cause of many, if

not most, of the biological invasions (Pastoret & Moutou, 2010).


CHAPTER 3

Materials and Methods

3.1. Transportation and handling of specimens

Clown knifefish of various sizes will be captured in Laguna de Bay by the local

fishermen. After capturing, the fishes will immediately be placed in separate containers with

slightly salty water (1-2% NaCl), and will be anesthetized lightly (Sukumasavin, 2007).

Tricaine methanesulfonate (MS-222) will be used for anesthetizing the fishes through

immersion at 100-200 mg/L dosage (Cruz-Lacierda, Dela Pena & Lumanlan-Mayo,

2000).Oxygen will also be provided for the fishes because of the long amount of time of

transportation from Laguna to University of Santo Tomas.

3.2. Laboratory set-up

Three size classes of Chitala ornata will be kept in three different aquaria in groups

of five. Small (S) Clown knifefishes with length of 30-35 cm, will be kept in aquaria of 80-

100 L (≈30 gallons), well-aerated, biologically and mechanically filtered. Medium-sized (M)

Chitala ornata specimens with size of 50-55 cm will be kept in aquaria of 190-300 L (≈100

gallons); and large (L) knifefishes of 70-75 cm in size will be kept in aquaria of 300-600 L

(≈200 gallons). The aquaria will be kept at 76oF to 80

oF or 24-28

oC, with pH 6 to 7 and

well-lit with LED moon or lunar lightings (Hargrove & Hargrove, 2006).


3.3. Experiments and Observations

3.3.1. Prey Selection

3.3.1.1. In captivity

Clown knifefishes will be separated into individual containers based on size, and will

be fed with a mixture of prey (Tilapia) sizes. Live prey fishes are divided to three size

classes: Small Tilapia (S) is 5-10 cm, Medium Tilapia (M) is 15-20 cm, and Large Tilapia

(L) is 25-30 cm. Prey size classes will be offered in either two or three prey size class

combinations. Preys will be available for 24 hrs, after which all prey will be removed and

noted (Juanes & Conover, 1994). The relationship between prey size and selection in Chitala

ornata will be examined.

3.3.1.2. Gut dissection

Approximately 3 Clown knifefishes of each size captured in Laguna de Bay will be

subjected to dissection once a month to know their gut contents in order to support our study.

3.3.2. Prey Consumption

Clown knifefishes of known body length and mass will be fed ad libitum. After 24

hours, any non-devoured prey will then be removed (Fishelson, 1997). The live prey fishes

will be weighed before and after feeding in order to determine the amounts of prey consumed

in three size classes of Chitala ornata.


3.3.3 Starvation

Following twelve weeks of ad libitum feeding, the Clown knifefish specimens will be

given no food for a period of time to study their ability to withstand starvation. The primary

reason for this experiment is to compare energy conservation in three size classes of Chitala

ornata specimens. Once a week, the fishes will be weighed to the nearest 0.5 g and then will

be again returned to their aquaria (Fishelson, 1997).

3.4. Data analysis

3.4.1. Prey Selection

3.4.1.1. In captivity

All the types of fishes that will be consumed by the Chitala ornata specimens on the

laboratory experiment will be recorded. The data will be tallied based on the size of the live

prey fishes consumed. Size selection data will be analyzed using a Chi-square test to detect

differences from a random choice. The three size class combinations will further be tested by

non-parametric Tukey-type multiple comparison test, in order to detect differences between

pairs of size classes (Juanes & Conover, 1994).

3.4.1.2. Gut dissection

The percent frequency occurrence (% FO) will be used to analyze the gut contents of

the Chitala ornata specimens that will be gathered in Laguna de Bay. The number of each

prey found inside the gut will be summed and will be divided by the total number of non-


empty stomachs dissected (Hyslop, 1980). Thus, the data will be calculated by using the

formula:

3.4.2. Prey Consumption

The weight (g) of the live prey fishes will be recorded before and after feeding. The

amounts of prey consumed will be determined in three size classes of Chitala ornata, which

is computed as prey consumed (g) = W i – W f , where W i and W f are the initial and final weights

(g) of the live prey fishes respectively. The resulting data from the computations will be

compared to each size of the Chitala ornata specimens in order to know if there exists a

significant difference on the prey consumption in the three size classes of Chitala ornata.

Accordingly, it shall be subjected to One-way ANOVA test. Differences will be considered

to be significant at p <0.05. All data shall be analyzed using SPPS software program for

statistical analysis (Sarkar, Deepak, Negi, Qureshi & Lakra, 2007).

3.4.3. Starvation

The initial weight of the Chitala ornata specimens before the experiment on starvation will

be determined. Their weight will be measured once a week and will be recorded. After the

starvation periods, the loss in body weight of the fish specimens will be computed from week

to week, which is computed as weight loss (g) = (W i – W f )/n, where W i and W f are the initial

and final weight (g) of all the fishes in an aquarium respectively, and n is the number of


fishes in an aquarium (Wang, Hayward & Noltie, 1998). The resulting data from the

computations will be compared to each size of the Chitala ornata specimens in order to

know if there exists a significant difference on the energy conservation in the different sizes

of Chitala ornata. Thus, it shall be subjected to One-way ANOVA test. Differences will be

considered to be significant at p <0.05. All data shall be analyzed using SPPS software

program for statistical analysis (Sarkar, Deepak, Negi, Qureshi & Lakra, 2007).


References

Arguelles, L.C., & Zilletti, B. (2005). Issues in bioinvation science. USA: Springer.

Albins, M.A., & Hixon, M.A. (2011). Worst case scenario: Potential long-term effects of

invasive predatory lionfish (pterois volitans) on atlantic and caribbean coral-reefcommunities. Environmental biology of fishes. doi: 10.1007/s10641-011-9795-1

Berthou, E.G. (2007). The characteristics of invasive fishes: what has been learned so far?

Journal of Fish Biology, 71, 33-55. doi: 10.1111/j.1095-8649.2007.01668

Clavero, M., & Berthou, E.G. (2005). Invasive species are a leading cause of animal

extinctions. TRENDS in Ecology and Evolution, 20(2). doi:

10.1016/j.tree.2005.01.003

Chitala ornata. (2012, July 3). Retrieved from http://www.fishbase.org/summary/Chitala-

ornata.html

Cinco, M. (2012, January 03). DENR studying use of turtles vs knife fish. Inquirer .

Retrieved from http://newsinfo.inquirer.net/205641/denr-studying-use-of-turtles-vs-

knife-fish

Cooke, F., & Bruce, J. (2004). The encyclopedia of animals: A complete visual guide. (p.

472). Australia: Weldon Owen, Inc.

Cruz-Lacierda , E. R., Dela Pena, L. D., & Lumanlan-Mayo, S. C. Southeast Asian Fisheries

Development Center, Aquaculture. (2000). The use of chemicals in aquaculture in the

philippines. . Retrieved from website:

http://repository.seafdec.org.ph/bitstream/handle/10862/433/9718511490_p155-

184.pdf

Delima, P. &Baldia, S. (2012). Limnological analysis of laguna de bay lake at binangonan

freshwater station: Its implication to plankton diversity. International Journal of

Ecology and Conservation, 2, 128-137.

Department of Environment and Natural Resources (DENR) (1990). Administrative Order

No. 34. Quezon City, Philippines.

Felongco, G.P. (May 19, 2012). Famous Philippine lake under threat from invasive species.In Gulf news. Retrieved January 7, 2013, from

http://gulfnews.com/news/world/philippines/famous-philippine-lake-under-threat-

from-invasive-specie-1.1024870

Fishelson, L. (1997). Experiments and observations on food consumption, growth and

starvation in dendrochirus brachypterus and pterois volitans (Pteroinae,Scorpaenidae). Environmental Biology of Fishes, 50, 391 – 403.

Galvez, J. (2012, May 19). New ‗monster‘ species out to ruin laguna lake. The Manila Times.Retrieved from http://www.manilatimes.net/index.php/news/nation/23168-new-


monster-species-out-to-ruin-laguna-lake

Guzman, M.A.L., & Estiva, J.A.N. (2006). A framework for the sustainability of laguna de

bay, Philippines.

Hargrove, M., & Hargrove, M. (2006). Freshwater aquariums for dummies. (2nd ed., p. 117).

Indianapolis, Indiana: Wiley Publishing, Inc.

Heinonen, K.B., & Auster, J.P. (2012). Prey selection in crustacean-eating fishes followingthe invasion of the asian shore crab hemigrapsus sanguineus in a marine temperate

community. Journal of Experimental Marine Biology and Ecology, 413, 177-183.

Hyslop, E. J. (1980). Stomach content analysis-- a review of methods and their application.

(Master's thesis) Retrieved from www.ru.ac.za/media/rhodesuniversity/content/hyslop

1980.pdf

Invasive species 101. (2012, April 5). Retrieved from http://www.invasive.org/101/index.cfm

Jaraula, C. (2001). Changes in Salinity and Sediment Supply in Laguna de Bay During the

Past 6,000 years. (Master‘s thesis, College of Science, University of the Philippines).

Juanes, F. & Conover, D. O. (1994, November 3). Piscivory and prey size selection in young

of- the-year bluefish: predator preference or size-dependent capture success?. Marine

Ecology Progress Series, 114(59-69),

‗Knife fish‘ threatening native species in laguna lake. (2012, May 21). Philippine Daily

Inquirer . Retrieved from http://newsinfo.inquirer.net/196945/‗knife-fish‘-threatening-

native-species-in-laguna-lake

Oledan, M. (2001). Challenges and opportunities in watershed management for laguna de

bay (Philippines). Lakes & Reservoirs: Research and Management, 6,243 – 246.

Palma, A., Diamante, A., & Pol, R. (2002). An assessment of fishery resources of laguna de

bay. Aquatic Ecosystem Health and Management, 5, 139 – 146.

Pastoret, P.P., & Moutou, F. (2010). Invasive species part 1: general aspects and biodiversity

part 2: concrete examples. (Master's thesis).

Perrings, C., Williamson, M., Barbier, E. B., Delfino, D., Dalmazzone, S., Shogren, J.,Simmons, P. & Watkinson, A. (2002). Biological invasion risks and the public good:

an economic perspective. Ecology and Society, 6 (1), Retrieved from

http://www.ecologyandsociety.org/vol6/iss1/art1/

Poulsen, A.F., Hortle, K.G., Hortle, J., Chan, S., Chhuon, C.K., Viravong, S.,

Bouakhamvongsa, K., Suntornratana, U., Yoorong, N., Nguyen, T.T., & Tran, B.Q.

(2004). Distribution and ecology of some important riverine fish species of themekong river basin. (Master's thesis) Retrieved from

http://w.mekonginfo.org/assets/Publications/technical/tech-No10-distribution-n-


ecology-of-important.pdf

Salaverria, L.B. (2012, May 30). Bfar solutions vs knife fish: Remove, destroy eggs. Philippine Daily Inquirer . Retrieved from http://newsinfo.inquirer.net/203769/bfar-

solutions-vs-knife-fish-remove-destroy-eggs

Santos-Borja, A. (2006). Laguna de bay: Experience and lessons learned brief. 225-258

Sarkar , U. K., Deepak, P. K., Negi, R. S., Qureshi, T. A. &Lakra, W. S. (2007). Efficacy of

different types of live and non-conventional diets in endangered clown knife fishchitala chitala (hamilton-buchanan) during its early life stages Aquaculture Research,

38, 1404-1410.

Sukumasavin, N. (2007). Advanced freshwater aquaculture: Fish reproduction. (Doctoral

dissertation) Retrieved from

http://www.fisheries.go.th/fish/web/TCTP/TCTP2008/LectureNote/09.pdf

Wang, N., Hayward, R. S., & Noltie, D. B. (1998). Effect of feeding frequency on food

consumption, growth, size variation, and feeding pattern of age-0 hybrid sunfish.

(Master's thesis).

Xie, Z., Chen, Z., Fan, D. & Xiong, G. (2003, October). Global consequences and control

strategies of biological invasion. The Journal of Applied Ecology, 14(10), Retrieved

from http://www.ncbi.nlm.nih.gov/pubmed/14986391

http://www.ncbi.nlm.nih.gov/pubmed/14986391





APPENDIX A

Flow Chart

Collection of Chitala

ornataLaboratory set-up

Experiments and

Observation on Prey

Selection and

Consumption

Experiments and

Observations on

Starvation

Data Analysis


APPENDIX B

Gantt Chart

Activities May Jun Jul Aug Sep Oct Nov Dec Jan Feb

Transportation andhandling of specimens

Laboratory set-up

Acclimation

Experiments andobservations on preyselection andconsumption

Starvation

Analysis of results

Manuscript writing

Thesis defense


APPENDIX C

Budget Proposal

Items Quantity Price Total Price

Aquaria

≈30 gallons

≈100 gallons

≈200 gallons

1

21

Php 1,000.00

Php 2,500.00Php 4,000.00

Php 1,000.00

Php 5,000.00Php 4,000.00

Tricaine methanesulfonate (MS-222) 1 Php 500.00 Php 500.00

Oxygen pump & filter

Small to medium-sized

Large-sized

21

Php 500.00Php 800.00

Php 1,000.00Php 800.00

Food fish

Live Tilapia (Oreohcromis sp.) of

various sizes

(per month)Php 5,000.00

(≈3 months) Php 15,000.00

LED Moon/ Lunar light 3 Php 1,500.00 Php 4,500.00

Chitala ornata specimens

For experimentation:

Small (30-35 cm)

Medium (50-55 cm)

Large (70-75 cm)

For gut observation:

Small (30-35 cm)

Medium (50-55 cm)

Large (70-75 cm)

555

333

Php 10.00Php 20.00Php 40.00

(per month)Php 10.00Php 20.00Php 40.00

Php 50.00Php 100.00Php 200.00

(≈ 3 months) Php 90.00

Php 180.00Php 360.00

TOTAL Php 32,780.00

Documents

Chapter 1-3 (with border).docx