1. Temporal and Spatial Distribution of Fish Larval Assemblages of the Tebrau Straits South Western Johore Peninsular Malaysia By A. Arshad, Roushon A., S K Daud & Mazlan A G Department of Biology Faculty of Science, UPM Email: azizar@fsas.upm.edu.my

2.  Biological and ecological information on fish larvae is essential for fisheries management.  Spawning ground and spawning season could be determined based on the spatio-temporal larval distribution data  Temporal patterns of variation in the composition of assemblages can also be used to determine dynamics of recruitment patterns of fish. Introduction

3. Objectives of the research 1.To establish the list of fish larvae found within the seagrass bed, mangrove, estuarine and open sea of the Tebrau’s Straits. 2.To determine the composition, abundance and distribution of fish larvae in the study areas.

4. Materials and Methods Study area:  The Study were conducted in the Tebrau Straits. Five (5) stations were selected:  St.1 (N 01 0 23.345 / ; E 103 0 36.741 / ), River Pendas  St.2 (N 01 0 22.790 / ; E 103 0 38.140 / ), R. Pendas Estuary  St.3 (N 01 0 21.597 / ; E 103 0 37.491 / ), Straits/ Mangrove  St.4 (N 01 0 19.414 / ; E 103 0 35.628 / ), Seagrass bed  St.5 (N 01 0 18.799 / ; E 103 0 35.246 / ), Open seas  Each sampling station is approximately 1 km apart from each other (Fig.1)Fig.1

5. Sampling:  Monthly sampling ‘was carried out during full moon/new moon period, at both high and low tides.  Samples of fish larvae were collected using Bongo net (Fig.2) through 30 min subsurface net towing.Fig.2  A flowmeter is attached to the net in order to determine the volume of the water filtered. Sampling period: October 2007 to March 2008

6. Habitat Parameters  At each sampling station, the following environmental parameters are being obtained by YSI multiparameter recorder:YSI  Temperature ( 0 C)  Dissolved oxygen (mg/L)  Salinity (ppt)  P H  Total dissolved solid (mg/L) &  Conductivity (mS/cm)

7. Sample Processing:  After each tow, samples were immediately fixed in 5% formalin and transported to the laboratory for further analysis.  Samples were sorted out to family level, taxonomically identified and permanently stored in 75% alcohol.  Identification to the family level using the appropriate literatures (Leis and Carson-Ewart, 2000; Kawaguchi, 2002)

8. Composition & Distribution In the laboratory fish larvae were sorted from the rest of zooplankton. Numerical estimation of larval abundance of different families were counted using a dissecting microscope.

9. Results

10. Environmental Parameters: Site Analysis Mean ± SD of the environmental parameters from the different stations were calculated and from the analysis of variance (ANOVA) stated that there were significant differences (P < 0.05) among the five stations (Table 1)Table 1 Environmental Parameters: Tidal Analysis Mean ± SD of the environmental parameters during low tide and high tide were also calculated and showed significant differences (P < 0.05) (Table 2)Table 2

11. Species Composition and Abundance A total of 34 families were identified. From these, 16 occurred in River, 22 in Estuary, 19 in Strait, 22 in Seagrass bed and 14 in Open sea. Among the 34 families, 13 families are commercially important (Table 3).Table 3 Overall, 5 families (Clupeidae, Blenniidae, Sparidae, Gobiidae and Sillaginidae) were the most common in term of numbers in the study areas.

12. Some Photographs of Fish Larvae Cynoglossidae, 50x Clupeidae. 40x Tetraodontidae, 50x Triacanthidae, 40x Monacanthidae, 50x Leiognathidae, 100x

13. Blenniidae, 50x Cynoglossidae, 45x Belonidae, 50x Syngnathidae, 25x Gobiidae, 50x

14. Samaridae, 50x Unidentified, 100x Sillaginidae, 50x Unidentified, 50x

15. Abundance and Spatial Distribution  The highest mean number (240.33 /unit effort) of fish larvae was found in the Merambong seagrass beds.  This was followed by the station 3 located in Tebrau Straits (fringed with mangroves) and lowest in the open sea area (Fig.4) An analysis of variance (ANOVA) stated that there were significant differences between the stations on the basis of abundance of fish larvae (p < 0.05) Fig.4. Spatial dist n of fish larvae

16. Spatio-temporal Distribution  The highest number (1074/unit effort) of fish larvae was found during the month of February in Merambong seagrass bed. (Fig.5)  Lowest number of fish larvae (6/unit effort) was found during the month of October in the upper river station (Fig.5) Fig.5. Temporal and spatial distribution of fish larvae

17. Correlation Bet n Larval Abundance and Environmental Parameters Parameters X Abundance Correlation co- efficient (r) Significance level at 5% level Comment Temp X abundance -0.073P> 0.05Not significant Sal X abundance0.328P> 0.05Not significant DO X abundance0.192P> 0.05Not significant Cod. X abundance-0.051P> 0.05Not significant P H X abundance0.212P> 0.05Not significant TDS X abundance0.318P> 0.05Not significant  There were no significant correlation between abundance of fish larvae and environmental parameters

18. Lists of Fish larvae known to exist in the coastal waters of Gelang Patah, Johore have been established. A total of 34 different families were identified from the coastal waters of Tebrau Straits, Johore. Summary of results

19. The average highest number ( 240.33 /unit effort) of fish larvae was found in Merambong seagrass bed and lowest in the open sea. An analysis of variance (ANOVA) stated that there were significant differences between the stations on the basis of abundance Summary of results

20. Temporal variations were observed on the abundance of fish larvae, where the highest number (1074/unit effort) of larvae was recorded in the month of February in seagrass bed and the lowest number (6/unit effort) was found in October of River Pendas station.. There were no significant correlation (P > 0.05) between the abundance of fish larvae and environmental parameters. Summary of results

21. THANK YOU FOR YOUR ATTENTION

22. Fig.1. Geographical location and three sampling stations

23. Fig.2. Bongo Net (Mesh size 500 µm, mouth diameter 0.3 m and length 1.3 m )

24. Fig. 4. Photograph of YSI

25. St-1. River of Pendas

26. St-2. Estuary

27. St-3. Straits of Teberau

28. St-4. Seagrass area

29. St-5. Open Sea