The influence of ocean dynamics and climate changes on the Lemuru (Bali Sardinella) abundance in the Bali Strait, Indonesia

Transcription

1 The influence of ocean dynamics and climate changes on the Lemuru (Bali Sardinella) abundance in the Bali Strait, Indonesia Mu>ara Rachmat Putri 1 Agus Se>awan 2 1 Research Group of Oceanography, Ins>tute Technology of Bandung (ITB), Bandung, INDONESIA 2 Agency for Marine & Fisheries Research & Human Resources Ministry of Marine Affairs & Fisheries (MMAF), INDONESIA

2 Outline Background Purposes Lemuru (Bali Sardinella) Data and Methodology The image cannot be displayed. Your computer may not have enough memory to open the image, or the image may have been corrupted. Restart your computer, and then open the file again. If the red x still appears, you may have to delete the image and then insert it again. Results and Discussion Conclusions Perancak Estuarine - Bali

3 Background - Why the Indonesian waters poten2al for fisheries? - General condi2on of Indonesian waters Indonesian Throughflow (ITF) and Monsoon Current North West Monsoon (DJF) Warm Pool of West Pasific Southeast Indian Ocean South East Monsoon (JJA)

4 Ocean Current System of Indonesia Seas (Mayer, et.al 2015)??

5 Sea Surface Temperature of Indonesia Seas (Mayer, et.al 2015)

6 Bathymetry of Bali Strait Bali Strait EAST JAVA Muncar Pengambengan BALI Bali Strait is a semi- enclosed waters with high produc2vity during east monsoon due to the occurrence of upwelling in the southern part. Perancak Estuarine - Bali

7 Lemuru (Bali Sardinella) living in the coastal area around Bali Strait and the eastern part of East Java with depths less than 100 m. At day2me, Lemuru mostly swim close to seabed and rise to the surface at night 2me. Their food is around 95% zooplankton (mostly copepods) and 5% phytoplankton. (IMRO, 2011) Chlorophyll- a abundance is usually used as an indicator for primary produc2on.

8 4,500 4,000 3,500 3,000 Issue : The capture of Lemuru decreased in the last 5 years (Jun 2010 un2l Jun 2014)? Catch (Tons) 2,500 2,000 1,500 1, (Hendiar2, et.al., 2005)

9 Purposes of the research To es2mate the horizontal and ver2cal distribu2on of chlorophyll- a in Bali Strait during east monsoon and second monsoon transi2on (JJA- SON). To analyze the influences of ocean dynamics and climate change to Lemuru s capture produc2on. ( )

10 Data and Methodology Analyzing the ocean dynamic using results from HAMburg Shelf Ocean Model (HAMSOM). baroclinic mode horizontal resolu2on of 6 (~ 9 km) Es2ma2ng the concentra2on of chlorophyll- a and primary produc2on around the Bali Strait using Gaussian Model Collec2ng oceanographic data around the Bali Strait through field observa2on Collec2ng available sta2s2cs data of Lemuru s capture produc2on from the Ministry of Marine Affairs and Fisheries (MMAF)

11 Gaussian Method Chl 0 *1 *1 *1 B 0 Chl Zmax Z max *2 *3 S *4 *4 h *4 *4 *4 σ Procedure for es2ma2ng five parameters from chlorophyll- a concentra2on at the surface (Chl 0 ). Chl Zmax is the maximum chlorophyll concentra2on at chlorophyll- a maximum layer. *1 Regression as func2ons of Chl 0 ; *2 Regression as func2ons of B 0 ; *3 Regression as func2ons of Chl Zmax ; *4 Calculated by equa2on as follows:

12 Ver2cal profile of chlorophyll- a concentra2on were measured in June and September 2012 and May 2013 by the Ins2tute for Marine Research and Observa2on (IMRO) - MMAF, Bali un2l 90 meters depth. Surface chlorophyll- a concentra2on (Chl 0 ) from MODIS. Table 1. Gaussian parameters to es2mate ver2cal distribu2on of chlorophyll- a concentra2on during first transi2on, east and second transi2on monsoons.

13 1 st Transi>on Monsoon East Monsoon Depth (m) Depth (m) The Vertical Profile of Chlorophyll Sta.C (May) Chl (mg/m 3 ) Observed Chl The Vertical Profile of Chlorophyll Sta.7 (May) Depth (m) The Vertical Profile of Chlorophyll St.2 (June) Depth (m) Chl (mg/m 3 ) Observed Chl Estimated Chl The Vertical Profile of Chlorophyll St.8 (June) nd Transi>on Monsoon Depth (m) Depth (m) The Vertical Profile of Chlorophyll St.6D (September) Chl (mg/m 3 ) Observed Chl Estimated Chl The Vertical Profile of Chlorophyll St.7D (September) Ver>cal profile of Chlorophyll- a concentra>on Es>ma>on vs Observa>on 100 Chl (mg/m 3 ) Observed Chl Estimated Chl Chl (mg/m 3 ) Observed Chl Estimated Chl Chl (mg/m 3 ) Observed Chl Estimated Chl

14 Results and Discussion 1. Hydrodynamic of Bali Strait 2. Ocean Produc2vity of Bali Strait 3. Interac2on of Ocean Dynamic and Lemuru

15 Hydrodynamic of Bali Strait

16 Sea Surface Temperature

17 Sea Surface Salinity

18 The es>ma>on of sea surface chlorophyll- a concentra>on in Bali Strait The monsoon influencing the concentra>on of chlorophyll- a: increased during east monsoon decreased during west monsoon un>l the 1st transi>on monsoon.

19 The maximum chlorophyll- a concentra2on (> 3 mg/m 3 ) during east monsoon is found at 10 meters depth, and becoming deeper (up to 20 meters) during the monsoon transi2on (MAM and SON) with concentra2on of 1.5 to 2 mg/m 3.

20 Es>ma>on of Net Primary Produc>on in the Bali Strait

21 The Fishing Ground of Lemuru in Bali Strait Muncar From the hydrodynamic model and es>ma>on of Chl and NPP

22 The rela>onship between 5- years averaged of Lemuru s capture produc>on and SST as well as chlorophyll- a concentra>on Jun Jul Aug Sep Oct Nov Catch (Ton) SST Jun Jul Aug Sep Oct Nov 0.0 Catch (Ton) Chl

23 The rela2onship between anomalies of SST and Lemuru s capture produc2on Anomaly of Catch or Landing in Muncar (Tons) Jan- 10 Mar- 10 May- 10 Jul- 10 Sep- 10 Nov- 10 Jan- 11 Mar- 11 May- 11 Jul- 11 Sep- 11 Nov- 11 Jan- 12 Mar- 12 May- 12 Jul- 12 Sep- 12 Nov- 12 Jan- 13 Mar- 13 May- 13 Jul- 13 Sep- 13 Nov- 13 Jan- 14 Mar- 14 May- 14 Jul- 14 Sep- 14 Nov Anomaly of Catch (Ton) Anomaly of SST (oc) MEI DMI SST Average = o C and Lemuru s Produc2on Average = Ton Correla2on : SST vs MEI : ; SST vs DMI : ; Catch vs SST : +0.8;

24 Number of Storm Occurrances at Southeast Indian Ocean hnp://

25 Conclusions The maximum concentra2on of chlorophyll- a that indica2ng ocean primary produc2on usually started to occur on July and reach its maximum on August. With lag 2me of 2-3 months, the maximum of Lemuru's capture produc2on usually occurred on November every year. Results from hydrodynamics numerical model for 5 years show that there was strong upwelling during this period. Insignificant changes on trend of (sea surface) temperature, but the capture produc2on of Lemuru tends to decrease. This condi2on probably occurs due to extreme weather condi2on (strong wind, strong currents, as well as big waves) and also decreased on seawater quality (no data?).

26 In general, results from this research can clearly explain the rela2onship between the current system, primary produc2on, and capture fisheries produc2on. The current system of Indonesian waters is strongly influenced by the monsoon, meanwhile the monsoon itself strongly influenced by the regional and global climate. While due to climate change the regional and global climate were shiped, therefore factors related to climate change become a key issue that should be taken into account on capture fisheries industries in Indonesia. Future Works : - Couple Hydrodynamic and Ecosystem Model - IBM or other Fisheries Modeling

27 Acknowledgment Thank you very much for the financial support from PICES to anend the Interna2onal Symposium Drivers of dynamic of Small Pelagic Fish Resources in Victoria, Canada, 6-11 March This result is part of research ac2vity The Ocean Current System of Indonesian Waters and its effects on Marine Fisheries Produc2on funded by Research and Innova2on, Ins2tute Technology of Bandung (ITB)

28 Contact : mu2ara.putri@fitb.itb.ac.id mu2ara.putri@gmail.com