paitoon paewkhao patcharee puntuleng kamolrat phuttharaksa

Abundance and Distribution of Economic Fish Larvae

in the Gulf of Thailand and Andaman Sea

Abundance and Distribution of Economic Fish Larvae

in the Gulf of Thailand and Andaman Sea

By

Paitoon Paewkhao

Patcharee Puntuleng

Kamolrat Phuttharaksa

ObjectivesObjectives

1. To study on diversity, abundance anddistribution of fish larvae

1. To study on diversity, abundance anddistribution of fish larvae

2. To study on spawning and nursing ground ofeconomic fishes

2. To study on spawning and nursing ground ofeconomic fishes

Materials and MethodsMaterials and Methods1. Sampling region and PeriodThe survey on fish larvae was conducted at 72 stations of 3 areas:

-Upper Gulf of Thailand: 11 stationsSamples were collected 6 cruises in January, March, May, July, September and November 2004

4 cruises in January, March, July and August 2005. by R/V Pramong 2.

Materials and MethodsMaterials and Methods- Middle Gulf of Thailand : 21 stations

Samples were collected 4 cruises in January, March,

May and July 2005 by R/V Pramong 1.

- Andaman Sea: 42 stations

Samples were collected 4 cruises in January,

February, March, and April 2004 and 5 cruises

January, February, March, April and May 2005 by

R/V Pramong 4

Sampling stations

Seasonal closure areas

RayongPet Buri

Prachuap Kiri Khan

Phang-Nga

Phuket

Kribi

Trang

Satun

Surat Thani

ChumphonGulf of Thailand

Andaman Sea

Myanmar

Malaysia

12 34 5

6 78 9

10 1112 13

19

14 15 1617 1820

21 2223 24

25 2627 28

29 30 3132

1 2

3 4 5

6 7 8 910

11 12 1314

15 16 1718 1920 21 22 2324 25 2627 28 2930 31 32

33 34 3536 37 38

39 40 41

42

Chon Buri Thailand

Sampling method

1.Fish larvae collection• The plankton net use in sampling was a ring net 45,65

and 60 cm. mesh size 330 micrometer

• The oblique trawls at bottom to sea surface level were operated at speed 2-3 knots. Approximately 10 minutes/hual

• Samples were kept in 10 % sea-water formalin.

• Fish larvae were preserved in 4 % neutralized formalin solution.

Sampling method

2.Fish larvae identification • Specimens were identified to 5 family (Engraulidae,

Clupeidae, Carangidae, Nemipteridae and Scombridae)

• Calculating number of fish larvae per 1,000 m3

T = 1,000t / Vwhen T = number of fish larvae in 1,000 m3

t = number of fish larvae in the samplesV = volumn of water passed through the plankton net V = n*N1*a

when n = revolution number recorded by the current meter N1 = constant of displacement (m) per 1 revolution a = surface area of the net opening (m2)

ResultsResults

1. Abundance and distribution of economic fish larvae in the Gulf of Thailand

1.1 Upper Gulf of Thailand

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Engraulid larvae (ind./1,000 m3)

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Engraulid larvae (ind./1,000 m3)

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Clupeid larvae (ind./1,000 m3)

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1.2 Middle Gulf of Thailand

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Engraulid larvae(ind./1,000 m3)

seasonal closure area

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Clupeid larvae(ind./1,000 m3)

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2. Abundance and distribution of economic fish larvae in the Andaman Sea

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seasonal closure area

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seasonal closure areaNemipterid larvae

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SummarySummary

1. Abundance and distribution of economic fish larvae in the Gulf of Thailand

1.1 Upper Gulf of ThailandEngraulid larvae were the most abundant in March 2004, Clupeid and Scombrid were in September 2004. High distributions of those economic larvae in the upper Gulf were found in the area of Prachuap Kiri Khan Province

1.2 Middle Gulf of Thailand

Engraulid, Nemipterid and Scombrid were in January 2005, found in nearshore and offshore of Chumphon and Surat Thani Province

Clupeid and Carangid were in March 2005 in the area of Surat Thani Province.

1.2 Andaman Sea

Engraulid was found in March 2005, Clupeid, Nemipterid and Scombrid were in April 2005.The highest density of Carangid was in January 2005.

The Scombrid larvae were highly distributed between Koh Rok of Krabi Province and Adang-Rawi archipelago of Satun Province.

The others were found the most from Phang NgaBay of Phang Nga Province to Krabi Province.

Thank youThank you