Diet Composition of Two Most Common Fish Larvae

in the Sungai Pulai Seagrass Bed, Johor, Peninsular Malaysia By

A. ARSHAD, ROUSHON A., S.M.N. AMIN, S.K. DAUD & MAZLAN A G

Laboratory of Marine Science & AquacultureInstitute of Bioscience

Universiti Putra Malaysia

INTRODUCTION

Studies of fish larvae are often the best Studies of fish larvae are often the best way to provide information of great value way to provide information of great value to managers of fishery resources to managers of fishery resources

These include location of spawning These include location of spawning grounds in term of space and time; type grounds in term of space and time; type of habitats used by fish during their larval of habitats used by fish during their larval phase; and what kind of foods being phase; and what kind of foods being taken.taken.

Different larval stages, consume different Different larval stages, consume different diets; composition of diets reflected by diets; composition of diets reflected by stomach content study is important for stomach content study is important for greater understand on their feeding greater understand on their feeding ecologyecology

INTRODUCTION Cont.

Feeding habits of fish larvae is essential for the Feeding habits of fish larvae is essential for the aquaculture purposeaquaculture purpose

Few ichthyological research particularly larvae Few ichthyological research particularly larvae and lack of published reports on the diet and lack of published reports on the diet composition of fish larvae in the countrycomposition of fish larvae in the country

Therefore, study on food items which led to Therefore, study on food items which led to determination of feeding habits were determination of feeding habits were undertakenundertaken

OBJECTIVES

To determine the major food item To determine the major food item presents in the gut of two most presents in the gut of two most common fish larvae in the Sungai Pulai common fish larvae in the Sungai Pulai seagrass bedsseagrass beds

To analyse the importance of diet To analyse the importance of diet composition based on simple resultant composition based on simple resultant index analysisindex analysis

METHODOLOGY

Study area and SamplingThe study was conducted in the Seagrass bed of Sungai Pulai Estuary (N 010 19.414/; E 1030 35.628/)

Monthly sampling from December 2007 to May 2008 was carried out during new moon period.

Samples of fish larvae were collected using Bongo net (500 μm) through 30 min subsurface net towing.

Fig.2. Geographical localtion Fig.2. Geographical localtion of the sampling stations of the sampling stations

Sample Processing:

After tow, samples were immediately fixed in 5% formalin and transported to the laboratory for further analysis.

From the samples two most common family viz. Terapontidae and Gobiidae were sorted out and preserved in 75% alcohol.

Identification of the two families was done using the references by Leis and Carson-Ewart (2004); Kawaguchi (2002)

Stomach Examination:

The total length of the specimens were taken using digital microscope

Then, their stomach was incised under microscope with fine needles and contents were examined.

The food items were identified to the possible lowest taxa followed by counted their number and frequency with a compound microscope.

Data Analysis:To analyze the composition of the stomach, percentage frequency of occurrence and percentage numerical abundance was followed (Chrisafi et al., 2007).

The relative importance of food items in the diet of Terapontidae and Gobiidae was assessed by Simple Resultant Index (%Rs) according to Mohan and Sankaran (1988)

RESULTS

Larva of the family Terapontidae

Larva of the family Gobiidae

Terapontidae:1. Gut is coiled2. Melanophore are on the ventral surface of the gut 3.Eye is rounded but moderate to large 4.Larvae are moderate to large, deep and compressed

Gobiidae: 1. Gut is triangular2. Melanophores are on the gut, dorsal and ventral of the body3. The eye is rounded4.Larvae are elongated to moderate in depth

Taxonomic Identification

Gut

Eye

Melanophore

Melanophore

Gut

Eye

Food Groups Food Items

1. Phytoplankton

Chromophyta, Dinoflagellate, Diatoms, CentricDiatoms, Chlamydomonas, Coscinodiscus sp.,

Euglena sp., Gonyaulax sp. and Other Species

2. Zooplankton: Ostracod, Copepod, Amphipod, Isopod, Paramecium sp., Larvaceans, Larval stage, Thaliacians (Tunicates), Decapods Appendages and Mysid

3. Insects

4. Part of algae

5. Plant like matter Dried roots, stems, grass leaves and parts ofunidentified plants

6. Appendages of crustacean

7. Debris

8. Unidentified species

Diet Composition

Copepod (100x) Centric diatom (100x)

Larval stage (Naupli) (100x)

Some food items found in the guts of larvae

Diet Composition of Terapontidae Larvae

The The Table 2 Table 2 shows the monthly shows the monthly percentage of occurrence (Fpercentage of occurrence (Fpipi) of food ) of food items in 80 guts of Terapontidae fish items in 80 guts of Terapontidae fish larvaelarvae

The highest percentage of occurrence was The highest percentage of occurrence was the the phytoplanktonphytoplankton (80%) and the lowest (80%) and the lowest percentage was percentage was the appendages of the appendages of crustaceanscrustaceans (1%) (1%)

Differences in phytoplankton groups taken Differences in phytoplankton groups taken with timewith time

     Months      

Food Dec Jan Feb March April MayAverage of 6

items     No. of guts     months      77 22 3030 55 66 3030Phytoplankton Phytoplankton 66.6766.67 8080 3838 4545 32.1432.14 60.2360.23 53.6753.67 Chlorophyta Chlorophyta 33.3333.33 4040 1818 1515 21.4321.43 27.9627.96 25.9525.95 DinoflagelateDinoflagelate 5.565.56 -- 22 1010 -- 4.304.30 3.643.64 DiatomDiatom -- -- 11 55 -- -- 11 Centric diatomCentric diatom -- -- -- 1010 7.147.14 -- 2.862.86 TriceratiumTriceratium -- -- -- -- -- 3.233.23 0.540.54 Diatom (Diatom (Isocrysis)Isocrysis) 5.565.56 -- -- -- -- -- 0.930.93 EuglenaEuglena sp. sp. -- -- 22 -- -- 3.233.23 0.870.87 CosconodiscusCosconodiscus sp. sp. -- -- 22 -- -- -- 0.330.33 Gonyaulax Gonyaulax sp.sp. -- -- -- -- -- 1.081.08 0.180.18 Other phytoplanktonsOther phytoplanktons 22.2222.22 4040 1313 55 3.573.57 20.4320.43 17.3717.37ZooplanktonZooplankton -- -- 1919 2020 28.5728.57 4.314.31 11.9811.98 OstracodOstracod -- -- 44 -- 3.573.57 -- 1.261.26 CopepodCopepod -- -- 33 1010 7.147.14 2.152.15 3.723.72 AmphipodAmphipod -- -- 11 -- -- -- 0.170.17 LarvaceansLarvaceans -- -- 44 -- -- -- 0.670.67 Larval stage (naupli)Larval stage (naupli) -- -- -- -- -- 1.081.08 0.180.18 Thaliacians (Tunicates)Thaliacians (Tunicates) -- -- -- -- -- 1.081.08 0.180.18 Decapod appendagesDecapod appendages -- -- 77 1010 14.2914.29 -- 5.225.22 MysidMysid -- -- -- -- 3.573.57 -- 0.600.60InsectsInsects -- -- 1010 55 7.147.14 -- 3.693.69Algae Algae 27.7827.78 2020 66 1010 7.147.14 16.1316.13 14.5114.51Plant like matterPlant like matter 5.565.56 -- 1010 55 10.7110.71 17.2017.20 8.088.08Appendages of crustaceanAppendages of crustacean -- -- 11 55 -- -- 11Debris Debris -- -- 99 55 14.2914.29 -- 4.724.72Unidentified itemsUnidentified items -- -- 66 55 -- 2.152.15 2.192.19

Table 2: Percentage frequency of occurrence (Fpi) of food items in 80 guts of Terapontidae

Diet Composition of Terapontidae Larvae

Table 3Table 3 shows monthly percentage of shows monthly percentage of numerical abundance (Cnumerical abundance (Cii) of food items in ) of food items in 80 guts of fish larvae from family 80 guts of fish larvae from family TerapontidaeTerapontidae

The predominant item recorded was The predominant item recorded was phytoplanktonphytoplankton (67.52%) and were highest (67.52%) and were highest for all sampling monthsfor all sampling months

ChlorophytaChlorophyta was the most important was the most important phytoplankton consumedphytoplankton consumed

     Months      

Food Dec Jan Feb March April MayAverage of 6

items     No. of guts     months      77 22 3030 55 66 3030Phytoplankton Phytoplankton 86.0786.07 91.6791.67 49.7249.72 47.547.5 52.9752.97 77.1677.16 67.5267.52 Chlorophyta Chlorophyta 74.2974.29 61.1161.11 28.9928.99 2020 48.2148.21 44.8344.83 46.2446.24 DinoflagelatesDinoflagelates 0.360.36 -- 0.550.55 55 -- 1.011.01 1.151.15 DiatomDiatom -- -- 0.550.55 1.251.25 -- -- 0.30.3 Centric diatomCentric diatom -- -- -- 2020 3.573.57 -- 3.933.93 TriceratiumTriceratium -- -- -- -- -- 0.720.72 0.120.12 Diatom (Diatom (Isocrysis)Isocrysis) 0.710.71 -- -- -- -- -- 0.120.12 EuglenaEuglena sp. sp. -- -- 0.550.55 -- -- 1.011.01 0.260.26 CosconodiscusCosconodiscus sp. sp. -- -- 4.954.95 -- -- -- 0.830.83 Gonyaulax Gonyaulax sp.sp. -- -- -- -- -- 0.140.14 0.020.02 Other phytoplanktonsOther phytoplanktons 10.7110.71 30.5630.56 14.1314.13 1.251.25 1.191.19 29.4529.45 14.5514.55ZooplanktonZooplankton -- -- 8.068.06 12.5012.50 11.3211.32 0.710.71 5.435.43 OstracodOstracod -- -- 2.202.20 -- 1.791.79 -- 0.670.67 CopepodCopepod -- -- 0.550.55 1010 1.791.79 0.430.43 2.132.13 AmphipodAmphipod -- -- 0.180.18 -- -- -- 0.030.03 LarvaceansLarvaceans -- -- 0.730.73 -- -- -- 0.120.12 Larval stage (naupli)Larval stage (naupli) -- -- -- -- -- 0.140.14 0.020.02 Thaliacians (Tunicates)Thaliacians (Tunicates) -- -- -- -- -- 0.140.14 0.020.02 Decapod appendagesDecapod appendages -- -- 4.404.40 2.52.5 5.365.36 -- 2.042.04 MysidMysid -- -- -- -- 2.382.38 -- 0.400.40InsectsInsects -- -- 7.167.16 1.251.25 2.982.98 -- 1.901.90Algae Algae 12.5012.50 8.338.33 3.673.67 2020 4.764.76 5.325.32 9.109.10Plant like matterPlant like matter 1.431.43 -- 19.4519.45 1.251.25 10.1210.12 16.3816.38 8.118.11Appendages of crustaceanAppendages of crustacean -- -- 0.180.18 3.753.75 -- -- 0.660.66Debris Debris -- -- 5.875.87 55 17.8617.86 -- 4.794.79Unidentified itemsUnidentified items -- -- 5.695.69 55 -- 0.430.43 1.851.85

Table 3: Percentage of numerical abundance (Ci) of food items in 80 guts of Terapontidae

Diet Composition of Gobiidae

The monthly percentage of occurrence The monthly percentage of occurrence (F(Fpipi) of food items in 88 guts of fish ) of food items in 88 guts of fish larvae from Gobiidae family are showed larvae from Gobiidae family are showed in in Table 4Table 4

The highest percentage of occurrence The highest percentage of occurrence for phytoplankton was found in January for phytoplankton was found in January (70%) and the lowest percentage was (70%) and the lowest percentage was insects (2.39%)insects (2.39%)

Copepods and ostracods were amongst Copepods and ostracods were amongst the major zooplanktons recordedthe major zooplanktons recorded

     Months      

Food Dec Jan Feb March April MayAverage of 6

items     No. of guts     months      1010 1010 3030 55 55 2828Phytoplankton Phytoplankton 5050 7070 37.4937.49 33.3333.33 45.8345.83 62.2062.20 49.8149.81 Chlorophyta Chlorophyta 3030 3535 18.2718.27 23.8123.81 20.8320.83 31.7131.71 26.6026.60 DinoflagelatesDinoflagelates -- -- 2.882.88 -- -- -- 0.480.48 Centric diatomCentric diatom -- -- -- -- 8.338.33 3.663.66 2.002.00 ChlamydomonasChlamydomonas 3.333.33 -- 0.960.96 -- -- -- 0.720.72 EuglenaEuglena sp. sp. -- 1010 -- -- 4.174.17 -- 2.362.36 CosconodiscusCosconodiscus sp. sp. -- -- -- 4.764.76 -- -- 0.790.79 Gonyaulax Gonyaulax sp.sp. -- -- -- -- -- 1.221.22 0.200.20

Other phytoplanktonsOther phytoplanktons 16.6716.67 2525 15.3815.38 4.764.76 12.5012.50 25.6125.61 16.6516.65

ZooplanktonZooplankton 13.3313.33 -- 19.2219.22 28.5728.57 12.5112.51 6.106.10 13.2913.29 OstracodOstracod -- -- 0.960.96 4.764.76 4.174.17 -- 1.651.65 CopepodCopepod 6.676.67 -- 2.882.88 4.764.76 -- 2.442.44 2.792.79 AmphipodAmphipod 3.333.33 -- 3.853.85 -- -- -- 1.201.20 IsopodIsopod -- -- 1.921.92 -- -- 2.442.44 0.730.73 Paramecium Paramecium sp.sp. -- -- -- -- 4.174.17 -- 0.700.70 LarvaceansLarvaceans 3.333.33 -- 4.814.81 -- -- -- 1.361.36 Larval stage (crab)Larval stage (crab) -- -- -- -- -- 1.221.22 0.200.20 Thaliacians (Tunicates)Thaliacians (Tunicates) -- -- 0.960.96 -- -- -- 0.160.16 Decapod appendagesDecapod appendages -- -- 2.882.88 19.0519.05 4.174.17 -- 4.354.35 MysidMysid -- -- 0.960.96 -- -- -- 0.160.16InsectsInsects -- -- 4.814.81 9.529.52 -- -- 2.392.39

Algae Algae 13.3313.33 -- 9.629.62 14.2914.29 12.5012.50 17.0717.07 11.1411.14

Plant like matterPlant like matter 23.3323.33 2525 11.5411.54 4.764.76 20.8320.83 10.9810.98 16.0716.07Debris Debris -- 1010 10.5810.58 4.764.76 4.174.17 -- 4.924.92Unidentified itemsUnidentified items -- -- 6.736.73 4.764.76 4.174.17 3.663.66 3.223.22

Table 4: Percentage frequency of occurrence (Fpi) of food items in 88 guts of Gobiidae

Diet Composition of Gobiidae

Table 5 Table 5 showed monthly percentage of showed monthly percentage of numerical abundance (Cnumerical abundance (Cii) of food items in 88 ) of food items in 88 guts of fish larvae from family Gobiidaeguts of fish larvae from family Gobiidae

The table also shows that the predominant The table also shows that the predominant item is phytoplankton (63.47%)item is phytoplankton (63.47%)

PhytoplanktonPhytoplankton was consistently forming the was consistently forming the top food item consumed throughout the top food item consumed throughout the period of observationperiod of observation

    Months      

Food Dec Jan Feb March April MayAverage of 6

items     No. of guts     months    10 10 30 5 5 28

Phytoplankton Phytoplankton 88.0888.08 83.1683.16 45.4145.41 47.9247.92 45.9845.98 70.2570.25 63.4763.47

Chlorophyta Chlorophyta 55.0555.05 73.6873.68 29.6629.66 33.3333.33 35.0635.06 34.9234.92 43.6243.62 DinoflagelatesDinoflagelates -- -- 1.841.84 -- -- -- 0.310.31 Centric diatomCentric diatom -- -- -- -- 3.453.45 0.620.62 0.680.68 ChlamydomonasChlamydomonas 0.460.46 -- 0.260.26 -- -- -- 0.120.12 EuglenaEuglena sp. sp. -- 2.112.11 -- -- 0.570.57 -- 0.450.45 CosconodiscusCosconodiscus sp. sp. -- -- -- 11.4611.46 -- -- 1.911.91 Gonyaulax Gonyaulax sp.sp. -- -- -- -- -- 0.410.41 0.070.07

Other phytoplanktonsOther phytoplanktons 32.5732.57 7.377.37 13.6513.65 3.133.13 6.906.90 34.3034.30 16.3216.32ZooplanktonZooplankton 1.841.84 -- 8.408.40 10.4110.41 7.477.47 2.072.07 5.035.03 OstracodOstracod -- -- 1.051.05 1.041.04 1.721.72 -- 0.640.64 CopepodCopepod 0.920.92 -- 0.790.79 1.041.04 -- 0.410.41 0.530.53 AmphipodAmphipod 0.460.46 -- 2.102.10 -- -- -- 0.430.43 IsopodIsopod -- -- 1.051.05 -- -- 1.451.45 0.420.42 Paramecium Paramecium sp.sp. -- -- -- -- 4.604.60 -- 0.770.77 LarvaceansLarvaceans 0.460.46 -- 1.311.31 -- -- -- 0.300.30 Larval stage (crab)Larval stage (crab) -- -- -- -- -- 0.210.21 0.040.04 Thaliacians (Tunicates)Thaliacians (Tunicates) -- -- 0.520.52 -- -- -- 0.090.09 Decapod appendagesDecapod appendages -- -- 0.790.79 8.338.33 1.151.15 -- 1.701.70 MysidMysid -- -- 0.790.79 -- -- -- 0.130.13InsectsInsects -- -- 3.153.15 2.082.08 -- -- 0.870.87Algae Algae 5.505.50 -- 7.617.61 26.0426.04 4.604.60 9.509.50 8.888.88Plant like matterPlant like matter 4.594.59 12.6312.63 14.9614.96 8.338.33 33.9133.91 17.1517.15 15.2615.26Debris Debris -- 4.214.21 17.0617.06 3.133.13 6.326.32 -- 5.125.12Unidentified itemsUnidentified items -- -- 3.413.41 2.082.08 1.721.72 1.031.03 1.371.37

Table 5: Percentage of numerical abundance (Ci) of food items in 88 guts of Gobiidae

Overall Diet Composition

The The phytoplanktonphytoplankton was the highest was the highest rank (60.85%) of food item found in rank (60.85%) of food item found in the gut of Terapontidae followed by the gut of Terapontidae followed by algaealgae (11.73%), zooplankton (11.73%), zooplankton (9.35%), plant matter (7.84%) (9.35%), plant matter (7.84%) (Table (Table 6)6)

Food items   Ci Fpi % Rs                 Phytoplankton Phytoplankton 67.5267.52 53.6753.67 60.8560.85 Chlorophyta Chlorophyta 46.2446.24 25.9525.95 36.3136.31 DinoflagelateDinoflagelate 1.151.15 3.643.64 2.612.61 DiatomDiatom 0.30.3 11 0.710.71 Centric diatomCentric diatom 3.933.93 2.862.86 3.333.33 TriceratiumTriceratium 0.120.12 0.540.54 0.380.38 Diatom (Diatom (Isocrysis)Isocrysis) 0.120.12 0.930.93 0.640.64 EuglenaEuglena sp. sp. 0.260.26 0.870.87 0.620.62 CosconodiscusCosconodiscus sp. sp. 0.830.83 0.330.33 0.610.61 Gonyaulax Gonyaulax sp.sp. 0.020.02 0.180.18 0.120.12 Other phytoplanktonsOther phytoplanktons 14.5514.55 17.3717.37 15.5215.52ZooplanktonZooplankton 5.435.43 11.9811.98 9.359.35 OstracodOstracod 0.670.67 1.261.26 0.980.98 CopepodCopepod 2.132.13 3.723.72 2.942.94 AmphipodAmphipod 0.170.17 0.560.56 0.400.40 LarvaceansLarvaceans 0.120.12 0.670.67 0.460.46 Larval stage (naupli)Larval stage (naupli) 0.020.02 0.180.18 0.120.12 Thaliacians (Tunicates)Thaliacians (Tunicates) 0.020.02 0.180.18 0.120.12 Decapod appendagesDecapod appendages 2.042.04 5.225.22 3.843.84 MysidMysid 0.400.40 0.600.60 0.490.49InsectsInsects 1.901.90 3.693.69 2.842.84Algae Algae 9.109.10 14.5114.51 11.7311.73Plant like matterPlant like matter 8.118.11 8.088.08 7.847.84Appendages of crustaceanAppendages of crustacean 0.660.66 11 0.820.82Debris Debris 4.794.79 4.724.72 4.604.60Unidentified itemsUnidentified items 1.851.85 2.192.19 1.961.96

Table 6: Overall diet composition of Terapontidae ranked by Simple Resultant Index (%Rs)

Overall Diet Composition

For Gobiidae, the For Gobiidae, the phytoplanktonphytoplankton (56.33%) was at the highest rank (56.33%) was at the highest rank index followed by index followed by plant matter plant matter (15.134%), zooplankton (9.84%) and (15.134%), zooplankton (9.84%) and algaealgae (9.73%) (9.73%) (Table 7)(Table 7)

Food items   Ci Fpi % Rs                 Phytoplankton Phytoplankton 63.4763.47 49.8149.81 56.3356.33 Chlorophyta Chlorophyta 43.6243.62 26.6026.60 34.8934.89 DinoflagelateDinoflagelate 0.310.31 0.480.48 0.390.39 Centric diatomCentric diatom 0.680.68 2.002.00 1.441.44 ChlamydomonasChlamydomonas 0.120.12 0.720.72 0.500.50 EuglenaEuglena sp. sp. 0.450.45 2.362.36 1.641.64 CosconodiscusCosconodiscus sp. sp. 1.911.91 0.790.79 1.411.41 Gonyaulax Gonyaulax sp.sp. 0.070.07 0.200.20 0.140.14 Other phytoplanktonsOther phytoplanktons 16.3216.32 16.6516.65 15.9215.92ZooplanktonZooplankton 5.035.03 13.2913.29 9.849.84 OstracodOstracod 0.640.64 1.651.65 1.211.21 CopepodCopepod 0.530.53 2.792.79 1.941.94 AmphipodAmphipod 0.430.43 1.201.20 0.870.87 IsopodIsopod 0.420.42 0.730.73 0.570.57 Paramecium Paramecium sp.sp. 0.770.77 0.700.70 0.710.71 LarvaceansLarvaceans 0.300.30 1.361.36 0.950.95 Larval stage (crab)Larval stage (crab) 0.040.04 0.200.20 0.140.14 Thaliacians (Tunicates)Thaliacians (Tunicates) 0.090.09 0.160.16 0.120.12 Decapod appendagesDecapod appendages 1.701.70 4.354.35 3.193.19 MysidMysid 0.130.13 0.160.16 0.140.14

InsectsInsects 0.870.87 2.392.39 1.731.73

Algae Algae 8.888.88 11.1411.14 9.739.73Plant like matterPlant like matter 15.2615.26 16.0716.07 15.1315.13Debris Debris 5.125.12 4.924.92 4.854.85Unidentified itemsUnidentified items 1.371.37 3.223.22 2.392.39

Table 7: Overall diet composition of Gobiidae ranked by Simple Resultant Index (%Rs)

CONCLUSIONS There were eight groups of food items in the There were eight groups of food items in the

guts of both fish larvae guts of both fish larvae (phytoplankton, zooplankton, algae, insects, plant like matter, appendages of crustaceans, debris and unidentified items).

In Terapontidae, phytoplankton was the first In Terapontidae, phytoplankton was the first ranked by Simple Resultant Index (60.85%) ranked by Simple Resultant Index (60.85%) followed by algae (11.73%)followed by algae (11.73%)

As for Gobiidae, the phytoplankton (56.33%) As for Gobiidae, the phytoplankton (56.33%) was also the highest rank followed by plant was also the highest rank followed by plant like matters (15.13%).like matters (15.13%).

From the diet composition, fish larvae of both From the diet composition, fish larvae of both family depends on phytoplanktons as their family depends on phytoplanktons as their main dietsmain diets

Universiti Putra Malaysia (UPM)

Universiti Kebangsaan Malaysia (UKM)

MOSTI Malaysia for the funding of the project & travel grant