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Gut Content Analysis of Siganus Canaliculatus (Danggit)

Renelee M. Subsuban

, Aileen S. Espra

, Krystel Joyce S. Alido

, Jeza E. Cuizon

, Alejandro R. Dejan,

Jr.

College Professor of Math and Science Department, University of Mindanao, Davao City, Philippines

Faculty of Department of Environmental Science, School of Interdisciplinary Studies, MSU-IIT, Iligan

City, Philippines

DOI:

https://doi.org/10.51584/IJRIAS.2025.10100000149

Received: 31 October 2025; Accepted: 07 November 2025; Published: 18 November 2025

ABSTRACT

The study aims to identify the gut content of Siganus canaliculatus (Danggit) found in a mangrove forest at Brgy.

Tagabuli, Sta. Cruz, Davao del Sur. Sampling was done in two sampling stations namely: Area 1 (mangrove

area) and Area 2 (aquaculture area). Results showed that percentage composition of prey items in Area 1

are

composed of algae (78%), plankton (13%) and detritus (9%), while Area 2 is composed mostly of detritus (62%),

algae (30%), planktons (7%) and others such as stone sediments, small shell crustacean and nylon fragments

(1%). Proximate composition of Siganus canaliculatus flesh in Area 1 has Crude fat (11%), Crude protein (48%)

and Ash (6%) while Area 2 has Crude fat (10%), Crude protein (51%) and Ash (28%). Siganus canaliculatus

gathered in mangrove and aquaculture area consumed similar prey items like Melosira spp. (Diatoms), Meridion

spp. (Diatoms), Nitzschia spp. (Diatoms), Ascartia spp. (Copepod) and Dreissena spp. (Zooplankton). Based on

gut content analysis of Siganus canaliculatus, it is herbivorous. Hence, algae as the primary prey item of Siganus

canaliculatus should be conserved, and harvesting of commercially important fishes should be monitored.

Keywords: Gut, content, analysis, Danggit, Siganus canaliculatus

INTRODUCTION

Fish gives more than one billion destitute individuals with a large portion of their day-by-day protein needs. As

a reasonably priced animal protein source in the least prosperous nations, fish is the essential wellspring of

nourishment, creating a developing interest for this staple (World Fish Center, 2015). A data from Philippine

Statistics Authority (2017) on Fisheries Statistics of the Philippines showed that the volume of production by

sector in the country from 2014 to 2016 was 4,689,084.71 to 4,355,792.42 metric tons.

In 2018, the Philippines ranked 8

among the top fish producing countries in the world with its total production

of 5.35 million metric tons (MT) of fish, crustaceans, mollusks, and aquatic plants (including seaweed). The

production of 211.87 million MT (FAO, 2020).

In 2020, the total volume of fisheries production in the Philippines reached 4.40 million metric tons, a slight

decrease from 4.42 million metric tons produced in 2019. This decline was attributed to a decrease in production

across aquaculture and municipal capture fisheries, partially affected by an increase in commercial capture

fisheries.

Philippine Statistics Authority (2024) provided a data that the Philippine fisheries sector saw a total production

of 4.04 million metric tons, with aquaculture accounting for the largest share at 54.9%. Specifically, aquaculture

production was 2.22 million metric tons, followed by marine municipal fisheries at 802.77 thousand metric tons

(19.8%) and commercial fisheries at 857.33 thousand metric tons (21.2%). Inland municipal fisheries contributed

the smallest share at 166.17 thousand metric tons (4.1%).

In 2024, Davao del Sur’s aquaculture production reached 18, 369.69 metric tons. Brackish water fishponds and

marine cages are subsectors with notable positive growth especially in 2024. Unfortunately, fish supplies are

neglecting to satisfy demands, and there are real deficiencies in some emerging nations where they are required

most (Sertori, 2009).

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According to Naylor, Goldburg, Primavera, Kautsky, Beveridge, Clay, Folke, Lubchenco, Mooney and Troell

(2000), roughly one-third of yearly wild fish landings in Southeast Asia are mangrove dependent. It is crucial to

thoroughly understand the diet of these commercially important fishes found in the area and the most frequently

used technique for determining the degree of food selectivity is gut content analysis. Gut content analyses are

advantageous in that one can identify selection from a wide range of natural prey (Mantyka & Bellwod, 2007).

Additionally, the gut content analysis gives an overall consideration about the type of food material available to

the animals in the food chain and ultimately it is a representation of food in the ecosystem (Babare, Chavan &

Kannewad, 2013). Moreover, the knowledge of diet composition and feeding habits is an essential introduction

to the natural history of any species (Ahlbeck, Hansson & Hjerne, 2012).

There are only a few comprehensive researches on the food habits of many fishes inhabiting mangrove forest

and their trophic group classification (Nanjo, Kohno & Sano, 2008). One example of fish species inhabiting

mangrove forest is Siganus canaliculatus. The International Union for Conservation of Nature (2016) reported

that Siganus canaliculatus are commercially exploited and conservation is needed. Understanding the fish diet

of Siganus canaliculatus would provide an idea of what food to conserve to increase the production of Siganus

canaliculatus in the community. Locally, little or no extensive work yet has been conducted on the stomach

content of Siganus canaliculatus (Danggit) most especially in Sta. Cruz, Davao del Sur which has a mangrove

area of 124 hectares (Municipal Assessor’s Office, Sta. Cruz, Davao del Sur). Thus, this study investigates the

gut content of Siganus canaliculatus (Danggit) at Sta. Cruz, Davao del Sur to determine the types of prey items

it consumes. Moreover, the comparison of the percentage of food availability to its gut content would lead to the

identification of its primary food.

LITERATURE REVIEW

Siganus canaliculatus are highly esteemed food fish throughout the western Pacific, like Guam, Palau, and the

Philippines (Bagarinao, Solis, Villaver & Villaluz, 1986). Siganus fishes have important commercial value; most

species are suitable, desirable for consumption and fetch medium to high prices in the markets. Although Siganus

fishes have relatively small sizes, they are delicious and have high demand in the markets (Tharwat & Al-

Owafeir, 2003). Siganids are herbivores that thrive in marine and brackish waters, found on the Indo-west Pacific

(Abdel-Aziz, Mohammed, Abou-Zied & Allam, 2016). It is commercially exploited, and local population

declines are suspected because of massive exploitation. It is a component of fisheries in many parts of its range,

but even where it is heavily exploited such as in the Philippines (International Union for Conservation of Nature,

2016). Understanding the role of autotroph in estuary food webs has important implications for management and

conservation. Early food web studies attempted to use gut content analysis of organisms at higher trophic levels

to clarify trophic dynamics (Melville & Connolly, 2003). Since the study of the feeding habits of fish and other

animals based upon analysis of stomach content has become standard practice, a sustenance propensity study

may be led to decide the most consumed prey or to choose the general significance of various food types to fish

nourishment and to evaluate the utilization rate of individual prey types (Hyslop, 1980).

A lot of food products are being harvested directly within the mangrove system through hunting, gathering, and

ﬁshing operations, making it vital coastal resources of commercial and fishery products (Kathiersan and

Bingham, 2001). Fish that live in mangrove waters are grouped into five according to feeding habits:

herbivorous, iliophagus, zooplanktivorous, benthic invertebrate feeder, and piscivorous species. These feeding

groups represent the results of a large number of studies devoted to analyses of fish gut contents (Robertson and

Blaber, 1992). Moreover, based on the study conducted by Grey, Thackeray, Jones & Shine (2002) on the gut

content analysis of Ferox Trout the researchers emphasizes that gut content analysis allows the stomach contents

of a predator to be quantified in terms of specific taxa ingested, but not necessarily assimilated. It provides only

information about feeding immediately before capture unless the predator in question exhibits little diet

heterogeneity. Another study conducted by Johannsson, Leggett, Rudstam, Servos, Mohammadian, Gal, Dermot

and Hesslein (2001), was about the diet and feeding rates of Mysis relicta. The results showed that Mysis function

as an essential intermediary, funneling energy from several pathways to the fish community. Mysis may dampen

fluctuations in energy flow within individual channels, helping to stabilize the fish community because Mysis

are a broad conduit. These have been traditionally determined through the analysis of gut contents.

Moreover, Linde, Grau, Riera, and Massuti-Pascual (2004) investigated the trophic ontogeny quantitatively in

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Epinephelus marginatus by testing and quantifying the effect of size on diet composition, and analyzing

complementary aspects of food preferences to clarify the importance of fish size on feeding habits. The results

showed that Epinephelus marginatus is a necto-benthic species that predate on a broad spectrum of decapod and

fish species frequenting rocky bottoms, as well as on the littoral cephalopods. According to the pattern found,

crustacean decapods are important preys of smaller groupers. However, as predators grow fishes and

cephalopods are incorporated into the diet, which together with crustaceans, are the principal preys of

intermediate fishes. Cephalopods were the preferred prey for larger fishes. Hence, the quantitative study of the

trophic ontogeny of E. marginatus represents a solid basis for the management of rocky littoral systems in which

this species would be implicated.

Importance of Proximate Composition of Fishes to Human.

Proximate composition refers to the percentage of the four main constituents namely: water, protein, lipid (fat

or oil) and ash (minerals). These major constituents make up the edible portion of fishes (Vikaspedia, 2019).

Fishes are valuable sources of food for human beings and other animals by most of the countries in the world.

They are rich in proteins and vitamins, especially, vitamin A. Thus, they play a significant role in the

socioeconomic aspect of the South-Asian countries. Fish consumption now exceeds that of all other animal

protein in tropical countries (Khabade, 2015).

Among the commercially important species are; Oreochromisniloticus, Clariasgariepinus, Tilapia zilli,

Schlibeintermediu, Mormyrusrume, Brycinius nurse, Heterotisniloticus, Hemichromisbimaculatus,

Hemichromisfasviatus, Labeus sp., Protopterusannectus, Synodontis spp., and Siganus spp. These species are

economically exploited for food and ornamental purpose (Wakil, Haruna, Mohammed, Ndirmbita, Yachilla, &

Kumai, 2014).

The study entitled “Proximate composition, amino acid and fatty acid estimation of Siganus lineatus” conducted

by Rajesh, Annadurai, Sattanathan and Shankar (2018), revealed that Siganus lineatus or Rabbit fish species

could compete with more commercially utilized species in terms of nutritional value. The Siganus are preferred

and consumed by all the economic group of people considering it as a low-cost fish. The fish sample collected

from Parangipettai and Cuddalore contained protein, carbohydrate, fat, ash and moisture content (63.2, 87.18%),

(19.23, 20.94), (124.1, 126.8), (10.29, 6.06), (13.39, 12.43) respectively. It was evident that these species

comprised of high protein, carbohydrate, lipid, and fatty acids. Also, they also contain essential and non-essential

amino acids, making it much more suitable for human consumption.

Prey Items Commonly Consumed by Fishes

Pollution of rivers and reservoirs in recent time affects the zooplankton population and changes in the trophic

levels of different food materials. This condition leads to changes in food and feeding habit of top carnivores in

the aquatic food chain including fishes. Therefore, it is essential to determine the food composition in the gut of

economically important fish species. The gut content analysis gives an overall consideration about the type of

food material available to the animals in the food chain, and ultimately it is a representation of food in the

ecosystem (Babare, Chavan & Kannewad, 2013).

All fish require energy for growth, breeding, and migration, obtained from its food sources (Bankole, Sule,

Okwundu & Amadu, 2001). The potential food resources of fish consist of all materials present in its

environment. They have been known to feed in an extensive variety of food items ranging from sand particles,

zooplankton, phytoplankton, plant leaves, roots, insects, insect larvae, crustaceans, worms, fishes, etc. (Omondi,

Yasindi & Magana, 2011). Fishes in the temperate environment are seasonal in their feeding. Digestion and

metabolic activities are slowed down at a lower temperature, so the amount of feed required in warm water

conditions is higher than that in cold water (David, Edward, Adass & Jesse, 2010). Meanwhile, Eya, Lacuna,

and Espra (2011) described the diet composition of selected economically important reef fishes in Maigo and

Kauswagan, Lanao del Norte, Philippines. Nine fish species belonging to seven families: Gerreidae

(Gerresoyena), Leiognathidae (Leiognathussplendens), Lethrinidae (Lethrinusinsulindicus), Scaridae

(Scarusbowersi), Siganidae (Siganus guttatus and Siganus vermiculatus), Theraponidae (Theraponjarbua and

Therapon sp.) and Mullidae (Upeneuscaeruleus) were used in the study. The result of the gut content analysis

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showed that the majority of the fish species (Gerresoyena, Leiognathaussplendens, Lethrinusinsulindicus,

Theraponjarbua, Therapon sp. and Upeneuscaeruleus) preyed on zooplankton and benthic animals. While some

species such as Scarusbowersi, Siganus guttatus, and Siganus vermiculatus entirely fed on algae and were

characterized as strict herbivores. The abundance of zooplankton between stations in Maigo, and Kauswagan,

Lanao del Norte showed no significant difference (p > 0.05) in both areas. Moreover, it showed that despite the

abundance of zooplankton in the environment, planktivorous fishes preferred to prey on some zooplankton

groups like copepods, amphipods, and crab. In their natural environment, Siganus feed on low energy and protein

algae, which results in sub-optimal growth and inconsistent production. However, in captivity, rabbit fish can be

trained to readily accept artificial feeds, making them suitable for commercial aquaculture (Parazo,1990).

Moreover, Sheaves and Molony (2000) investigated the extent to which Epinepheluscoioides, E. malabaricus

and Lutjanusargentimaculatus from 3 mangrove systems on the northeast coast of tropical Australia prey on

sesarmid crabs, and how closely these species are linked to mangrove productivity relative to sympatric species.

Sheaves and Molony utilized three estuaries on the northeastern coast of Australia for the study sites: Gentle

Annie Creek, Press's Pocket and the Hinchinbrook Channel. Crabs of the brachyuran subfamily Sesarrninae

dominated the diets of Epinepheluscoioides, E. malabancus and Lutjanusargentimaculatus in the mangrove

systems studied. The proportion of empty stomachs decreased, and the percentage of sesarmids in the diets

increased during the first part of the falling tide. During the low and early rising tide, there was an increase in

the proportion of empty stomachs and a decrease in the sesarmid content. During the late flood tide, the

percentage of empty stomachs stopped increasing and leveled out, indicating that many fish had captured fresh

prey. In turn, the diet of E. coioides, E. malabaricus, and L. argentimaculatus imply that they derive much, or

even most, of their nutrition from primary consumers. Recent work using stable isotopes of Lugendo,

Nagelkerken, van der Velde and Mgaya (2006) has confirmed the earlier work on fish diets but has clarified gut

contents previously labeled ‘detritus,' ‘indistinguishable,' or “amorphous.”

Furthermore, Wakil, Haruna, Mohammed, Ndirmbita1, Yachilla and Kumai (2014) conducted a study on the

contents of two commercially important fish species of Catfish and Tilapia fish (Clariasgariepinus and

Oreochromisniloticus) respectively from Lake Alau, North – Eastern Nigeria. The results obtained indicated that

121 (35%) fish had empty stomach content in Clariasgariepinus and 145 fish had empty stomach content in

Oreochromisniloticus representing 41% out of the three hundred and fifty (350) individual fish of each species

examined. It showed that the stomach contents of Clariasgariepinus consisted of animal and plant materials,

planktons, and others. Fish prey was the dominant animal material (51%) with a mean contribution of 32% by

volume, and plant material consisted of leaves and debris (6% by volume). On the other hand,

Oreochromisniloticus contained primarily of animal and plant materials, planktons and detritus. Algae from the

group Chlorella, Volvox, Scenedesmus, Pediastrum, and Spirogyra species accounted for 66% by volume

followed by detritus and mud with 20%, zooplankton represented by Daphnia and Moina species represented

the low food content by volume with 8%. The study revealed the importance of algae, fish, insects and plant

materials as food for fish in Lake Alau, and zooplanktons form essential items in the diet of the species examined.

Both species are omnivorous and occupy the same ecological niche; hence, according to authors, there is the

need to control pollution into the lake to prevent eutrophication.

Finally, El-Sayed (1994) conducted a study of the feeding habits of Siganus canaliculatus and Siganus javus

fingerlings in the Arabian Gulf waters of Qatar. The investigation revealed that seagrasses and benthic

filamentous algae are the primary dietary component of S. canaliculatus and S. javus during their fingerlings and

juvenile stages. However, many studies conducted analyzing the gut content of other species of Siganids showed

that the algae preferred by captive fish were not always those found in greatest quantity in the gut. Aside from

algal food, they can also feed accidentally on some nondigestible substances such as mollusk shells and other

invertebrates attached to algae (Sabour & Lakkis 2007).

MATERIALS AND METHODS

Sampling Area

Sampling was conducted in the mangrove forest of Brgy. Tagabuli, Sta. Cruz, Davao del Sur. Sta. Cruz is also

part of the Davao Gulf ecosystem. It has eleven barangays with wide coastal areas, namely: Inawayan, Darong,

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Astorga, Coronon, Zone I, Zone II, Zone III, Zone IV, Tuban, Tagabuli and Bato. Its shoreline is 24.8 kilometers,

and the municipal water is 37,200 hectares. Mangrove area is 124 hectares with “bakhaw, pagatpat, potutan and

tangal” (Rhizopora spp. and Sonneratia spp.) as dominant species (Municipal Assessor’s Office, Sta. Cruz,

Davao del Sur). The sampling site was situated within longitudes 125°16'10" and 125°29'25" E and latitudes

6°46'46" and 6°59'22" N, bounded on the North by Davao City; on the East by Davao Gulf; and on the West and

South by Digos City. Two different stations were plotted along the mangrove forest (Figure 2). Area 1 is a

mangrove area away from the aquaculture zone while Area 2 is situated near the aquaculture zone. The locations

of each station were established through GPS (GPS Google Map).

Collection of Siganus Canaliculatus

Twenty (20) individuals of Siganus canaliculatus (Danggit) from two different areas were bought from the

fishermen who collected the fish samples. Collection of fishes by the fisher folks was done using a fishing net

with a height of 5 to 10 m, length of 300 m and a small size mesh. The collection of fish samples was done twice

a month until twenty (20) individuals of Siganus canaliculatus (Danggit) was attained from each sampling

station. The collected Siganus canaliculatus (Danggit) from each station were placed in separated cellophane and

were labeled with its local name, sampling station number and the date and time of collection. All collected

fishes were put in an icebox partially filled with ice to slow down metabolic activities of Siganus canaliculatus

(Danggit) (David et al., 2010). For photo documentation and fish identification, the collected Siganus

canaliculatus fishes are taken to the laboratory of the BFAR at Brgy. Tagabuli, Sta. Cruz, Davao del Sur.

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Identification of Siganus Canaliculatus

The collected Siganus canaliculatus (Danggit) species were examined for the identification of its morphological

structure, and each was photo documented. The total and standard length of each fish individual was measured

to the nearest 1cm. It was also weighed individually to obtain total weight to the nearest 1g, and all the data were

recorded (Zacharia and Abdurahiman, n.d.). Preliminary identification of the fish sample used in the study was

made by the researchers based on the morphological characteristics documented. The atlas and journals available

online were used as reference and guide for the identification. Moreover, the researchers also consulted the fisher

folks who are knowledgeable about identifying the common fishes they found in the area. For further verification

in the identification of the collected fish species, an expert from the Bureau of Fisheries and Aquatic Resources

in the region was consulted.

Gut Content Analysis of Siganus canaliculatus

Abdominal cavity of Siganus canaliculatus (Danggit) individuals was opened by carefully cutting along the mid-

ventral axis from the anus to below the gill chambers to avoid cutting of the stomach. Intact stomach was

removed from the fish and was weighed. The weight of the stomach with its content was recorded. For the

analysis, a longitudinal cut was made across the stomach, and the contents were preserved with 70% ethanol.

The empty stomach was weighed again. The total weight of the stomach contents was determined by getting the

difference between the importance of the intact stomach and the weight of the empty stomach. Preserved stomach

contents were examined under the electric compound microscope, and contents were identified up to the genus

level depending on the state of digestion (Eya et al., 2011).

Following the standard method of Hobson (1974), each prey item was scaled from 0 to 1 using 0.05 point method,

with the total contents considered as 1. The volumetric scale value of each prey item was examined from the

result of the point method. The product of the total weight of stomach content and its volumetric scale provides

the weight of each prey item in the stomach of each fish (Eya et al., 2011).

The formula for the Ranking Index of each prey item is: RI = (A/B) where:

RI = Ranking Index of each prey item

A = number of fish individuals per taxa containing each prey item

B = total number of the fish individual per taxa with stomach content

C = percentage of each prey item which can be computed as:

C=Volumetric scale of the prey item / Volumetric scale of all prey items combined x 100

The point method is significantly used in this study because it accounts for both the abundance and volume of

food items, providing a more comprehensive view than counting alone, especially for food items that are difficult

to count, like plant material or small organisms. It is a rapid and easy method that assigns points to different food

items based on their visual assessment, with more points given to more common or larger items. This allows for

the estimation of a diet's composition, even when contents are partially digested or have different

sizes. Furthermore, ranking indexes are a highly important tool in diet composition studies because they provide

a standardized, quantitative, and holistic way to measure and compare diet quality.

In this study, comparison of prey items in the gut of Siganus canaliculatus to its sizes was also done. On the other

hand, recorded total length of each fish individual was also classified. The different size group of Siganus

canaliculatus has measurements of 9-11 cm, 12-14 cm, 15-17 cm, 18-20 cm and 21-23 cm (Al-Marzouqi et al.,

2013).

Analysis of the Proximate Composition of Siganus canaliculatus Flesh

Analysis of the proximate composition of Siganus canaliculatus (Danggit) flesh was done by the laboratory

analyst of Davao Analytical Laboratory. Proximate analysis refers to the study of the four essential constituents

of fish muscle, which is the edible portion of fish. These four significant constituents include water, protein,

lipid (fat or oil) and ash (minerals). The percentage composition of the major components of fish muscle is

defined as the proximate composition (Vikaspedia, 2019).

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In this present study, proximate composition of the fish muscle major constituent (protein, fat and ash content)

was analyzed for three months and the results of the proximate composition from two different sampling areas

were compared.

Statistical Analysis

One-way analysis of variance (ANOVA) was used to get the variations of each prey items in the gut of Siganus

canaliculatus (Danggit) from each sampling station. The same tool was used in determining the significant

difference of the proximate composition of Siganus canaliculatus flesh and Siganus canaliculatus lengths

between the two areas. The analysis of variance test is vital for analyzing factors that affect a given data set. The

test allows a comparison of more than two groups at the same time to determine whether a relationship exists

between them. It analyzes multiple groups to identify the types between and within samples (Investopedia, 2018).

RESULTS AND DISCUSSION

The food composition of Siganus canaliculatus (Danggit)

Preliminary identification of the gut content of Siganus canaliculatus (Danggit) found in a mangrove forest at

Brgy. Tagabuli, Sta. Cruz, Davao del Sur was presented in Table 1. The food composition was categorized into

four major food categories namely: algae, planktons, detritus, and “others." In Area 1, the algae group includes

green and brown macroalgae. The other preliminary identified prey items under algae group include

Rhodophycean such as Audouinella spp., a dinoflagellate like Peridinium spp., and diatoms such as Aulacoseira

spp., Melosira spp., Meridion spp., and Nitzschia spp. The algae group in Area 2 was composed of seaweeds as

well as diatoms including Diploneis spp., Melosira spp., Meridion spp., Nitzschia spp., and Synedra spp. Other

algae present involved Cylindrocapsa spp., Eremosphaera spp., Tolypothrix spp., and Stylonema spp.

The copepods such as Ascartia spp., and Cyclops spp., and other zooplankton such as Dreissena spp., and

Globigerinoides spp., constitutes the plankton group found in the gut of Siganus canaliculatus (Danggit)

collected from Area 1.

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In Area 2, the copepods namely Ascartia spp., Paracalanus spp., and Pseudocalanus spp., together with Balanus

spp., Dreissena spp., and Globigerinoides spp., constitutes the plankton group.

Another prey item group labeled in the food composition was the detritus or degraded fragment and “others."

The other food materials found in Area 1 are stone sediments and small shell crustacean while in Area 2 are

sediments, small clamshell and nylon fragment respectively.

Percentage composition of each prey items

The gut of Siganus canaliculatus typically lies on the left side of the body. The intestinal wall is rather thick,

becoming thinner in the lower regions (Bryan, 1975). According to Al-Marzouqi, Al-Nadhi, and Al-Habsi

(2009), the functional morphology of the gut of Siganus canaliculatus is designed for herbivore feeding. Thus,

the result shows that the food mostly consumed were consisted of macroalgae, microalgae and some planktonic

species. Additionally, the identified gut content in this study was categorized in terms of algae, plankton, detritus,

and others.

In area 1, algae occupied the highest percentage found inside the gut which is 78% then planktonic species fall

second at 13% (Fig. 3). Since microalgae, macroalgae and phytoplankton communities showed high production

yields in mangrove areas (Cuenca, Macusi, Abreo, Ranara, Andam & Cardona, 2015), this supports the reason

why the Siganus canaliculatus caught nearby the mangrove expanses had a high consumption of such food items.

In Area 2, detritus ranks the highest having 62% of the total food consumption of Siganus canaliculatus, and the

algae come second having 30% (Fig. 3). Since area 2 is plotted near the aquaculture zone, the fishes usually

consume commercial fish feeds, and this shows why degraded food fragment or detritus contributes the highest

in the whole prey composition found inside the gut. Seemingly, commercial fish feeds take a little time to be

degraded by fishes than the other prey items (Pupulawaththa, 2018).

Rank of each prey items in terms of percentage composition

Figure 4 illustrates the ranking index of each prey item in Area. Algae (45.24) rank first as the most consumed

prey, followed by detritus (41.337), then planktons (2.033) and lastly “others” (0.051). This implies that Siganus

canaliculatus mostly feeds on macroalgae and microalgae making them herbivore feeding type of fish. It

indicates that the diet of Siganus canaliculatus is usually on the availability of the resources in different areas.

This is also supported by the study of Al-Marzouqi et al. (2009) which states that most of the Siganus

canaliculatus feed mainly on seaweeds and seagrasses. Also, the research conducted by Bariche (2006) in East

Mediterranian showed that Siganus rivulatus ingest majority of macrophytes which also supports the claim that

Siganus canaliculatus are indeed herbivore feeding fishes.

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In Figure 5, detritus or degraded food (35.64) ranks the highest in Area 2. It was followed by algae (27.75), then

plankton (0.82) and lastly “others” (0.054). It indicates that Siganus canaliculatus frequently consume easily

digested prey items which could be fish feed pellets. This can also be proven in the proximate composition of

the fish.

Prey items in the gut of Siganus canaliculatus in various size groups

As shown in Figure 6, the prey items of Siganus canaliculatus (Danggit) in Area 1 indicate high algae

consumption with 71.43% in size group measuring 9-11 cm, 70.80% in size group 12-14 cm, and 69.00% in size

group 15-17 cm.

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Area 2 has a different data output as shown in Figure 7. The percentage of prey items specifically the detritus

occupied mostly the highest percentage with 71.00% in size group 12-14 cm. In size group 15-17 cm, it held

67.00%; in size group 18-20 cm, it has 43.00% and; in size group 21-23 cm, it has 67.00%.

It can be observed that the Siganus canaliculatus size in Area 1 has a minimum of 9 cm and a maximum of 17

cm. In Area 2, the minimum size is 12 cm, and the maximum size is 23 cm. This data suggests that the food

consumed by the Siganus canaliculatus had a significant impact on their volumes. Since Area 2 is plotted near

an aquaculture zone, the detritus is composed mainly of washed away commercial fish feeds, and this gave a

growth advantage to the fishes that grew in Area 2. Prepared or artificial diets such as the commercial fish feeds

are considered complete diets; complete diets supply all the ingredients (protein, carbohydrates, fats, vitamins,

and minerals) necessary for the optimal growth and health of the fish. Most fish farmers use complete diets,

those containing all the required protein (18-50%), lipid (10-25%), carbohydrate (15-20%), ash (< 8.5%),

phosphorus (< 1.5%), water (< 10%), and trace amounts of vitamins, and minerals (Craig, 2002). In contrast,

supplemental (incomplete, partial) diets are intended only to help support the natural food (insects, algae, small

fish) ordinarily available to fish (Houlihan, Bouiard, & Jobling, 2001). This supports the idea in Area 1 where a

high percentage of algae consumption covers an incomplete diet.

Proximate composition of Siganus canaliculatus flesh

Total crude fat, crude protein and ash contents of Siganus canaliculatus flesh from two sampling areas are shown

in Table 2. It presents the average percentage of the proximate composition of Siganus canaliculatus tested from

September to November 2018. Crude fat content was higher in Area 1 with a percentage of 10.60% while Area

2 has 9.53%. Crude protein was higher in Area 2 with a value of 50.60% whereas Area 1 has 48.30%. Ash

content was also higher in Area 2 with the value of 27.83% compared to Area 1 which has only 6.13%.

As presented in Figure 1, algae occupied the highest percentage (78%) of the prey items found inside the gut of

Siganus canaliculatus (Danggit) in Area 1. This algae group encompasses phytoplankton (microalgae) floating

in the water, to large seaweeds (macroalgae) attached to the ocean floor. The role of phytoplankton as the

essential nutritional source of fish and its biochemical composition was emphasized in an article. According to

the author, phytoplankton provides important phytonutrients and biological components especially fatty acids,

amino acids, organic minerals, sterols, enzymes, trace elements, vitamins, carotenoids, and chlorophyll. With

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regards to the biochemical composition of phytoplankton, the most nutritional and highest in amount are lipids

or fat, which has an impact on the growth, health, and reproduction of fish species (Napiórkowska-Krzebietke,

2017). Thus, it supports the idea why crude fat content was higher in Area 1 than in Area 2 because algae were

found to be the highest in the percentage of the prey items found inside the gut of Siganus canaliculatus.

In contrast to Area 1, the food composition of Siganus canaliculatus (Danggit) in Area 2 constituted mainly of

detritus where it occupied the highest percentage (62%) of the prey items instead of algae. The detritus

components were described to contain degraded commercial fish feeds because the area sits near the aquaculture

zone. As described by Pupulawaththa (2018), in comparison to other food items, the degradation of commercial

fish feeds takes a little time inside the gut of fishes. Generally, commercial fish feeds contain the highest

percentage of protein (18-50%) and the other natural components fortified in commercial fish feeds include

lipids, carbohydrates, ash and trace amounts of vitamins and minerals (Craig, 2017). Proximate composition of

Siganus canaliculatus (Danggit) in Area 2 contains the highest percentage of crude protein (50.60%) followed

by ash content with 27.83%. It is because Siganus canaliculatus (Danggit) collected in Area 2 feeds on the

washed away commercial fish feeds supplied by the fish cages located near the area.

The Result of Statistical Analysis

Table 3 shows the ANOVA result on the difference of the prey items in Area 1 and Area 2. The obtained P-value

(0.996925) is higher than (0.05) level of significance. Hence, there is no significant difference in the prey items

found between the two (2) sampling stations. This indicates that the prey items are available in both areas whether

if it is along the mangrove area or near the aquaculture owned by BFAR and some local owners in Brgy.

Tagabuli, Sta. Cruz, Davao del Sur. Therefore, Siganus canaliculatus (Danggit) feeds on the available prey items

in the areas. Similar results were obtained from a related study conducted on the diet of Streaked spinefoot

(Siganus javus) from three coastal bays in Mindanao. It shows that the diet of Siganus fishes is usually on the

availability of the resources in different environments S. javus inhabits.

Table 4 presents the statistical analysis for the proximate composition of Siganus canaliculatus (Danggit) flesh

in Area 1 and Area 2. The obtained P-value (0.394051) is higher than (0.05) level of significance. Hence, the

result shows no significant difference in the proximate values found in the Siganus canaliculatus flesh collected

from two areas. This indicates that Siganus canaliculatus collected in the mangrove area can compete with the

Siganus canaliculatus collected from the mangrove area situated near the aquaculture zone in terms of nutritional

value. The study of Rajesh, Annadurai, Sattanathan & Shankar (2018) on proximate composition of Siganus

lineatus supported this observation wherein it showed that in terms of nutritional value Siganus lineatus could

compete with more commercially utilized species.

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Table 5 presents the statistical analysis of the fish lengths of Siganus canaliculatus in Area1 and Area 2. The

obtained P-value (0.771245) is higher than (0.05) level of significance with no differences between size classes

detected, concerning the plotted areas. According to Linde, Grau, Riera, and Massuti-Pascual (2004), it is

possible to obtain a function that could be used to estimate the mass proportions of prey items ingested by a

stock based on its size structure. However, the prediction is limited to the percentage variation of the gut content

associated with the evaluated factor, so one prediction would be more or less approximate to the current diet of

a stock according to the magnitude of this percentage. In this study, the result showed that there is no significant

difference between the percentage of prey items ingested in Area 1 and Area 2. Thus, explains the reason why

there is no significant difference between fish sizes.

Gut content analysis of Siganus canaliculatus (Danggit) found in a mangrove forest at Brgy. Tagabuli, Sta. Cruz,

Davao del Sur was identified. The percentage of each prey item in the gut of Siganus canaliculatus (Danggit)

from Area 1 (mangrove area) and Area 2 (aquaculture area) was determined and ranked. Moreover, the

percentage of crude fat, ash and crude protein of Siganus canaliculatus from the two sampling areas were also

established.

Results showed that the percentage composition of food items in Area 1 was composed of algae (78%), plankton

(13%) and detritus (9%). In Area 2, percentage composition was comprised of detritus (62%), algae (30%),

plankton (7%) and others (1%). Crude fat content was higher in Area 1 with a percentage of 10.60% while Area

2 has 9.53%. In area 2, crude protein was higher with the value of 50.60% whereas Area 1 has 48.30%. Ash

content was also higher in Area 2 with the value of 27.83% compared to Area 1 which has only 6.13%.

The following conclusions are made by the researchers based on the findings of the study:

1. The identified gut content of Siganus canaliculatus (Danggit) was consists of macroalgae, microalgae,

detritus and some planktonic species.

2. Percentage composition of food items in Area 1 was composed of algae (78%), plankton (13%), and

detritus (9%). On the other hand, the percentage composition in Area 2 was composed of detritus (62%),

algae (30%), plankton (7%), and others (1%).

3. Algae rank first as the most consumed prey item in the gut of Siganus canaliculatus in Area 1 while it ranks

second in Area 2. Hence, Siganus canaliculatus are herbivores.

4. In terms of proximate composition, crude fat was higher in Area 1 while crude protein and ash contents

were higher in Area 2.

5. There is no significant difference in the percentage of each prey item found in the gut of Siganus

canaliculatus (Danggit).

Based on the above-mentioned findings and conclusions of this study, the proponents came up with the following

recommendations:

1. Sta. Cruz community. The Sta. Cruz community could benefit from seminars and community meetings

hosted by local government units or BFAR about environmental preservation and conservation of food

materials (prey items). Since Siganus canaliculatus preyed on these prey items, it would, in turn, leads to

conservation of this fish species. This would also help in maintaining a balanced ecosystem and for them

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to not experience a scarcity on fish products most especially Siganus canaliculatus (Danggit). Hence, algae

as the primary prey item of Siganus canaliculatus should be conserved, and harvesting of commercially

important fishes should be monitored.

2. Bureau of Fisheries and Aquatic Resources. More studies can be conducted by BFAR internally to better

give future researchers a baseline data on diet composition and gut content analysis of Siganus

canaliculatus (Danggit) and other fishes.

3. Department of Environment and Natural Resources. The DENR can collaborate with the local community

to conduct mangrove planting activities to ensure that mangrove forests are not depleted on the parts where

commercial fishing is done.

4. Future Researchers. Interested researchers can conduct this study on different study locale or in the same

sampling area but on different types of fishes aside from Siganus canaliculatus (Danggit).

Studying other fish species in Tagabuli, Sta. Cruz, Davao del Sur would be highly recommended as they play a

vital role in maintaining the ecological balance of the area and knowing what they consume could give us an

overview of how long they will be able to keep their population. Moreover, seasonal sampling is recommended

to see variations on the fish gut content. Furthermore, since Siganus canaliculatus consume phytoplankton and

zooplankton, it would be more accurate to identify the plankton and algae species if DNA barcoding is

CONCLUSION

Gut content analysis is crucial in understanding the feeding habits, dietary preferences, and the role of a Siganus

canaliculatus in an ecosystem, providing insights into fish health, ecological interactions, and resource

management.

The following conclusions were drawn from the study.

The identified gut content of Siganus canaliculatus (Danggit) was consists of macroalgae, microalgae, detritus

and some planktonic species. The percentage composition of food items in Area 1 was composed of algae (78%),

plankton (13%), and detritus (9%). On the other hand, the percentage composition in Area 2 was composed of

detritus (62%), algae (30%), plankton (7%), and others (1%). Algae rank first as the most consumed prey item

in the gut of Siganus canaliculatus in Area 1 while it ranks second in Area 2. Hence, Siganus canaliculatus are

herbivores. In terms of proximate composition, crude fat was higher in Area 1 while crude protein and ash

contents were higher in Area 2. Statistically, there is no significant difference in the percentage of each prey item

found in the gut of Siganus canaliculatus (Danggit).

RECOMMENDATIONS

Based on the findings, the following recommendations were made:

1. Algae, the primary prey item of Siganus canaliculatus should be conserved, and harvesting of commercially

important fishes should be monitored regularly.

2. Extensive studies can be conducted by BFAR to better give future researchers a baseline data on diet

composition and gut content analysis of Siganus canaliculatus (Danggit) and other commercially important

fishes.

3. The Department of Environment and Natural Resources (DENR) together with the local community must

conduct mangrove planting activities to ensure that mangrove forests are not depleted on the parts where

commercial fishing is done.

4. Seasonal sampling is recommended to see variations on the fish gut content. Furthermore, since Siganus

canaliculatus consume phytoplankton and zooplankton, it would be more accurate to identify the plankton

and algae species through DNA barcoding.

Conflict Of Interest

No conflict of interest exists.

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REFERENCES

1. Abdel-Aziz, M. F., Mohammed, R. A., Abou-Zied, R. M., & Allam, S. M. (2016). Effect of feeding frequency

and feeding time on growth performance, feed utilization efficiency and body chemical composition on

Rabbitfish Siganus rivulatus fry and juvenile under laboratory condition. Egyptian Journal of Aquatic Biology

and Fisheries, 20 (3), 35 - 52.

2. Ahlbeck, B., Hansson, S. & Hjerne, O. (2012). Evaluating fish diet analysis methods by individual-based

modelling. Canadian Journal of Fisheries and Aquatic Sciences, 69, 1184-1201. doi:10.1139/f2012-051.

3. Al-Marzouqi, A., Al-Nadhi, A. & Al-Habsi, S. (2009). Stomach contents and length-weight relationship of

the white-spotted rabbitfish Siganus canaliculatus (Park, 1797) from the Arabian Sea coast of Oman. Journal

of Marine Biology 51(2): 211-216

4. Babare R. S., Chavan, S. P. & Kannewad, P. M. (2013). Gut content analysis of Wallago attu and Mystus

(Sperata) seenghala. The common Catfishes from Godavari River System in Maharastra State. Advances in

Bioresearch, 4(2), 123- 128.

5. Babbie, Earl R. The Practice of Social Research. 12th ed. Belmont, CA: Wadsworth Cengage, 2010; Muijs,

Daniel.Doing Quantitative Research in Education with SPSS. 2nd edition. London: SAGE Publications, 2010.

http://libguides.usc.edu/writingguide/quantitative

6. Bagarinao, T. U., Solis, N. B., Villaver, W. R. & Villaluz, A. C. (1986). Important fish and shrimp fry in

Philippine coastal waters: Identification, collection and handling. (Aquaculture extension manual No. 10).

Tigbauan, Iloilo, Philippines: Aquaculture Department, Southeast Asian Fisheries Development Center.

7. Bankole, N.O., Sule, O. D., Okwundu, E. C. & Amadu, M. (2001). Preliminary investigation into the fresh

and catch assessment survey of Lake Alau. Annual report to National Institute for freshwater fisheries, pp.

22.

8. Bariche, M. (2006). Diet of the Lessepsian fishes, Siganus rivulatus and S. luridus (Siganidae) in the eastern

Mediterranean: A bibliographic analysis. Cybium, 30(1), 41-49.

9. Bilogica. (n.d.). Retrieved from https://biologica.ca/organisms-we-identify/fish-stomach-contents/.

10. Bryan, P. (1975). Food Habits, Functional Digestive Morphology, and Assimilation Efficiency of the

Rabbitfish Siganus spinus (Pisces, Siganidae) on Guam. Pacific Science. 29,3 p. 269-277.

11. Cuenca, G., Macusi, E., Abreo, N., Ranara, C., Andam, M., Cardona, L., et al. (2015). Mangrove Ecosystems

and Associated Fauna with Special Reference to Mangrove Crabs in the Philippines: A Review. IAMURE

International Journal of Ecology and Conservation, 15(1).

12. Craig, S. (2017). Understanding fish nutrition, feeds, and feeding. Virginia Cooperative Extension 420-256.

Retrieved from www.ext.vt.edu.

13. David, D. L., Edward, A., Adass, P. A. & Jesse, C. (2010). Some aspect of water quality and the Biology of

Clarias gariepinus in Vimtim Stream, Mubi Adamawa State, Nigeria. World Journal Fish Marine Science,

2(2), 129-133.

14. El-Sayed, A.M. (1994). Feeding habits of rabbitfishes, Siganus canaliculatus and Siganus javus fingerlings

from the Arabian Gulf waters of Qatar. Indian Journal of Marine Sciences, 23, 112-114

15. Eya, A. R., Lacuna, D. G., & Espra, A. S. (2011). Gut content analysis of selected commercially important

species of coral reef fish in the Southwest Part of Iligan Bay, Northern Mindanao, Philippines. Publications

of the Seto Marine Biological Laboratory, 41, 35-49.

16. Food and Agriculture Organization (FAO) 2020. Retrieved from https://www.bfar.da.gov.ph/wp-

content/uploads/2022/02/2020-Fisheries-Profile-Final.pdf.

17. Froese, R. & Pauly, D. (2018). FishBase. World Wide Web electronic publication. Retrieved from

www.fishbase.org.

18. Google maps. Retrieved from:

https://www.google.com/maps/place/Tagabuli,+Santa+Cruz,+Davao+del+Sur).

19. Grey, J., Thackeray, S. J., Jones, R. I., & Shine, A. (2002). Ferox Trout (Salmo trutta) as Russian dolls':

complementary gut content and stable isotope analyses of the Loch Ness foodweb. Freshwater Biology, 47(7),

1235-1243.

20. Hobson, E. S. (1974). Feeding relationships of teleostean fishes on coral reefs in Kona, Hawaii. Fishery

Bulletin, 72, 915-1031.

21. Houlihan, D. F., Boujard, T., & Jobling, M. (Eds.). (2001). Food intake in fish. Blackwell Science.

INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN APPLIED SCIENCE (IJRIAS)

ISSN No. 2454-6194 | DOI: 10.51584/IJRIAS |Volume X Issue X October 2025

Page 1677

www.rsisinternational.org

22. Hyslop, E.J. (1980) Stomach Contents Analysis A Review of Methods and Their Application. Journal of Fish

Biology, 17, 411-429.

23. International Union for Conservation of Nature. (2016). Retrieved from

http://www.iucnredlist.org/details/69689554/0.

24. Investopedia. (2018). Analysis of variance (ANOVA). Retrieved from https://www.investopedia.com.

25. Johannsson, O. E., Leggett, M. F., Rudstam, L. G., Servos, M. R., Mohammadian, M. A., Gal, G., & Hesslein,

R. H. (2001). Diet of Mysis relicta in Lake Ontario as revealed by stable isotope and gut content

analysis. Canadian Journal of Fisheries and Aquatic Sciences, 58(10), 1975-1986.

26. Kathiresan, K. & Bingham. (2001). Centre of advanced study in Marine Biology. Annamalai University.

27. Khabade, S. A. (2015). Study of gut contents of major carps for their food habits from Sidddhewadi lake of

Tasgaontahsil of Sangli district Maharashtra. International Journal of Fisheries and Aquatic Studies, 2(4S),

01-04.

28. Koya, K. M., Kumar, V. V., Azeez, A., Sreenath, K. R., Dash, G., Bhadiya, S., et al. (2018). Diet composition

and feeding dynamics of Trichiurus lepturus Linnaeus, 1758 off Gujarat, north-west coast of India. Indian

Journal of Fisheries, 65.

29. Linde, M., Grau, A., Riera, F. & Massuti-Pascual, E. (2004). Analysis Of Trophic Ontogenyin Epinephelus

Marginatus (Serranidae). Cybium 28(1): 27-35.

30. Lugendo, B. R., Nagelkerken, I., van der Velde, G., & Mgaya, YD. (2006). The importance of mangroves,

mud and sand flats, and seagrass beds as feeding areas for juvenile fishes in Chwaka Bay, Zanzibar: Gut

content and stable isotope analyses. J Fish Biol 69:1639–1661.

31. Mantyka, C. S. & Bellwood, D. R. (2007), Macroalgal grazing selectivity among herbivorous coral reef fishes.

MARINE ECOLOGY PROGRESS SERIES. Vol. 352: 177–185.

32. Melville, A. J., & Connolly, R. M. (2003). Spatial analysis of stable isotope data to determine primary sources

of nutrition for fish. Oecologia, 136(4), 499-507.

33. Nanjo, K., Kohno, H., & Sano, M. (2008). Food habits of fishes in the mangrove estuary of Urauchi River,

Idiomata Island, southern Japan. Fisheries Science, 74(5), 1024-1033.

34. Naylor, R. L., Goldburg, R. J., Primavera, J. H., Kautsky, N., Beveridge, M., Clay, J., et al. (2000). Effect of

aquaculture on world fish supplies. Nature, 405 (6790), 1017 - 1024.

35. Napiórkowska-Krzebietke, A. (2017). Phytoplankton as a basic nutritional source in diets of fish. J. Elem.,

22(3): 831-841. DOI: 10.5601/jelem.2016.21.4.1375.

36. Omondi, R., Yasindi, A. W., Magana, A. M. (2011). Spatial and temporal variations of zooplankton in relation

to some environmental factors in Lake Baringo, Kenya. Eger. J. Sci. Technol. 11: 29-50.

37. Parazo M.M. (1990). E¡ect of dietary protein and energy level on growth, protein utilization and carcass

composition of rabbit¢sh, Siganus guttatus. Aquaculture 86, 41-49.

38. Philippine Statistics Authority. (2017). Fisheries statistics of the Philippines. Retrieved from

http://psa.gov.ph/sites/default/files/FStatPhil14-16docx%282% 29.pdf.

39. Philippine Statistics Authority. (2024). Retrieved

from:https://www.pressreader.com/philippines/businessmirror/20250130/281513641836733?srsltid=AfmB

OorRj2HYaoSn2BmETSUzFHlliU3tNVJcnWgjWdCTWhoTGzThiB3d.

40. Pupulawaththa, A. (2018). Disintegration and Degradation of Fish Feed Pellets and Feces Under Aerobic

Marine Conditions. Norway.

41. Rajesh, R., Annadurai, D., Sattanathan, G. & Shankar, M. (2018)

42. Robertson, A. I. & Blaber, S. J. M. (1992). Plankton, epibenthos and fish communities. pp. 173-224 pp. In:

Robertson AI and Alongi DM Tropical Mangrove Ecosystems. Coastal and Estuarine Studies. 41. American

Geophysical Union. 329 p.

43. Sabour W., Lakkis S., (2007) Diet and feeding habits of Siganus rivulatus and S. luridus two Red Sea migrants

in the Syrian coastal waters (Eastern Mediterranean). Rapp Comm int Mer Medit 38:584.

44. Sertori, T. (2009). Meats, fish, eggs, nuts, and beans. New York: Marshall Cavendish Benchmark.

45. Sheaves, M. & Molony, B. (2000). Short circuit in the mangrove food chain. Marine Ecology Progress Series,

199, 97-109.

46. Tharwat, A. & Al-Owafeir, M. (2003). Comparative study on the rabbit fishes Siganus Canaliculatus inhabit

the Arabian Gulf and Siganus rivula Tus inhabit the Red Sea in Saudi Arabia. Department of Aquatic Research

Facility of Agricultural Sciences and Food King Faisal University, PO Box 420, Hofuf, 31982 Saudi Arabia.

INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN APPLIED SCIENCE (IJRIAS)

ISSN No. 2454-6194 | DOI: 10.51584/IJRIAS |Volume X Issue X October 2025

Page 1678

www.rsisinternational.org

47. Vikaspedia. (2019). Chemical composition of fish. Retrieved from

http://vikaspedia.in/agriculture/fisheries/post-harvest-and-marketing/processing-in-fisheries/chemical-

composition-of-fis

48. Wakil, U. M., Haruna, A. B., Mohammed, G. A., Ndirmbita1, W. L., Yachilla, B. M. & Kumai, M. U. (2014).

Examinations of the stomach contents of two fish species (Clariasgariepinus and Oreochromisniloticus) in

Lake Alau, North – Eastern Nigeria. Agriculture, Forestry and Fisheries, 3(5), 405-409.

49. World Fish Center. (2015). Retrieved from https://www.worldfishcenter.org/content/annual-report-

20142015-0.

50. Worldwide Fund Global. (2009) Issues brief; no. 1701.

51. Zacharia, P. U. (n.d.). Trophodynamics and Review of methods for Stomach content analysis of fishes.

52. Zacharia, P.U. & Abdurahiman, K.P. (n.d.). Methods of stomach content analysis of fishes. CMFRI Winter

School on Towards Ecosystem Based Management of Marine Fisheries – Building Mass Balance Trophic and

Simulation Models.