jsps nat. coordinator meeting 18 – 20 may ’08 renaissance hotel malacca universiti kebangsaan...

JSPS Nat. Coordinator Meeting18 – 20 May ’08 Renaissance Hotel Malacca

UNIVERSITI KEBANGSAAN MALAYSIA

The Resiliency of Archerfish in Malaysian Estuaries

by

Mazlan A.G., Simon K.D. & Arshad A.

1


Contents

• Introduction• Materials and methods• Results and discussion• Conclusion• References

5 main heading........

2


Introduction

Archer Fish

• There are seven species in the genus Toxotes, commonly referred to as archer fish

• They are remarkably accurate in their shooting for feeding

• Occur in fresh, brackish and marine water; from India to Philippines, Australia and Polynesia.

• Toxotes jaculatrix and Toxotes chatareus are two common species in Malaysia.

3


The two species

T. chatareus T. jaculatrix

4


Associate with mangroves since devonian!What factors ensuring their resiliency?

5


Feeding technique ?i.e Trophodynamic

Reproductive Strategies?

6


Taxonomic position

Kingdom : Animalia

Phylum : Chordata

Subphylum : Vertebrata

Class : Actinopterygii

Order : Perciformes

Family : Tetrodontidae

Genus : Toxotes

Species : T. chatareus & T. jaculatrix

7


Objectives of the research

1. To carry out morphometric and meristic study of T. chatareus and T. jaculatrix.

2. To determine the diet of T. chatareus and T. jaculatrix.

3. To determine the age composition and growth rate of T. chatareus and T. jaculatrix

4. To study some reproductive biology aspect of T. chatareus and T. jaculatrix

4 Objectives

8


Materials and Methods

Research activities

Stomach content analysis

Morphometric & Meristic counts

Laboratories

Reproductive biology

Age determination

Sample collection

Weight

Measuring length

Preserved in formalin/ alcohol

Water quality analysis

Field / Sampling sites

9


Sampling sites

Site 1 = Matang Mangrove Forest, Perak

Site 2 = South Johore Mangrove Forest, Johor

10


Fish collection by different nets

Cast net

Skimming net

Gill net

11


Laboratory works

Dissect Fish

Estimate the annual fecundity

Morphometric & meristic analysis

Stomach

Preserved in Gilson fluid

Scales

Liver

Otolith

Otolith

Archer fish

Age determination

Separate Internal organs

Gonad

12


Morphometric study

Length measurement scale

Weighing scale

TL

FL

SL

PDL

PCL

OL

ED

PAL

PVL

SNL

DCP

13


Stomach content analysis

Weighing & measuring

Dissection

Preserved in 70% Alcohol

Identify the contentsusing microscope

Length & Full stomach weight

Empty stomach weight

Stomach content weight

Trophodynamic analysis

Stomach

14


Results and discussion

The form of the equation is:

Where,

• WT, is total weight (g),

• TL, is total length (cm), and

• a and b are constants for each species.

(WT) = a (TL)b

Length weight relationship

15


Total catch, length and weight of two archer fish species

Species Total catch (N)

Length (cm) Weight (g)

Max. Min. Max. Min.

T. chatareus 63 22.5 9.8 270.2 13.33

T. jaculatrix 65 23 8.7 275.31 13.41

16


Length weight relationships of T. chatareus fish species

8 10 12 14 16 18 20 22 24

0

50

100

150

200

250

300W = 3.31041L1.21916

R2 = 0.96007 a = 3.31041±0.28082b = 1.21916±0.00571

Body w

eight

(g)

Total Length (cm)

17


Length weight relationships of T. jaculatrix fish

species

8 10 12 14 16 18 20 22 24

0

50

100

150

200

250

300W = 3.80491L1.20382

R2 = 0.96287 a = 3.80491±0.26677b = 1.20382±0.00469

Bod

y w

eigh

t (g)

Total Length (cm)

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Regression parameters of 2 species

Species Regression Parameters

a s.e. b s.e. r2

T. Chatareus 1.21916 0.005713.31041 0.28082

0.96007

T. jaculatrix1.20382 0.00469 3.80491 0.26077

0.96287

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Meristic Analysis

Species DFR PCFR PVFR AFR CFR DS AS PS LLS

12 13 5 16 17 5 3 1 28

T. chatareus 12 13 5 16 17 5 3 1 25

12 12 5 16 17 5 3 1 29

12 15 5 17 17 5 3 1 35

12 13 5 17 17 5 3 1 37

12 14 5 17 17 5 3 1 38

Species DFR PCFR PVFR AFR CFR DS AS PS LLS

11 13 5 15 17 4 3 1 28

T. Jaculatrix 12 14 5 15 17 4 3 1 26

11 14 5 15 17 4 3 1 27

12 14 5 16 17 4 3 1 28

12 15 5 16 17 4 3 1 30

11 15 5 17 17 4 3 1 30

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Meristic study

Absent

5 th dorsal spine

Present

T. chatareus T. jaculatrix

21


Stomach content of T. chatareus & T. jaculatrix

Insecta

Crustacean

22


Trophic level of T. chatareus

0 10 20 30 40 50 60

3.0

3.5

4.0

4.5

Trop

hic

leve

l

Individual

23


Trophic level of T. jaculatrix

0 10 20 30 40 50 602.5

3.0

3.5

4.0

4.5

5.0

5.5T

roph

ic le

vel

Individual

24


Number of full and empty T. chatareus stomachs by size category

< 10 10-15 > 150

5

10

15

20

25

30

35

No.

sam

pled

Size catagory (cm)

Full Empty

25


Number of full and empty T. jaculatrix stomachs by size category

<10 10-15 >150

5

10

15

20

25

30

No.

sam

pled

Size catagory (cm)

Full Empty

26


Number of Preys ingested by T. chatareus according to size category

< 10 10-15 > 150

102030405060708090

100110120130140150160170180

No.

of

Prey

s

Size catagory (cm)

Crab Insect Shrimp/prawn Teleost

27


Number of Preys ingested by T. jaculatrix according to size category

< 10 10-15 > 150

20

40

60

80

100

No.

of

Prey

s

Size catagory (cm)

Crab Insect Shrimp Teleost

28


Prey items observed in Archer fish stomachsSpecies Prey category N W % Wt n Fo w

Crustaceans 175 46.53 76.92 70 111.11 0.74

T. chatareus Crab 151 43.89 72.55 57 90.48 0.69Shrimp/Prawn 24 2.64 4.36 13 20.63 0.04

Insects 328 13.96 23.08 57 90.47 0.22

Formicidae 153 6.51 10.76 49 77.78 0.1

Dytiscidae 73 3.11 5.14 37 58.73 0.05

Araneidae 57 2.42 4 27 42.86 0.04

Cerambycidae 45 1.92 3.17 23 36.51 0.03

Teleosts 0 0 0 0 0 0

Total 503 60.49 1000 127 201.59 0.96

Crustaceans 184 26.59 69.03 71 109.23 0.41

Crab 156 25.59 66.43 54 83.08 0.39

T. jaculatrix Shrimp/Prawn 28 1.03 2.67 17 26.15 0.02Insects 205 9.81 25.47 47 72.31 0.15

Formicidae 97 4.64 12.04 43 66.15 0.07

Dytiscidae 51 2.44 6.33 41 63.08 0.03

Araneidae 43 2.05 5.32 37 56.92 0.04

Cerambycidae 14 0.67 1.74 13 20 0.01

Teleosts 2 2.12 5.50 1 1.54 0.03

Toxotidae 2 2.12 5.50 1 1.54 0.03

Total 391 38.52 100 119 183.08 0.5929


Conclusion

Both species indicates allometric negative (b<3) growth condition

Stomach content and trophic level analysis denoted that T. chatareus and T. jaculatrix are strongly carnivorous

Feeding priority Crustaceans=Insects> Teleosts

30


Thanks to all for listening

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