Environment and Productivity patterns of Indian EEZ ________________________________________________________________________ Marine Research -Living Resources (MR-LR) Assessment Programme Report Cruise 251 FORV Sagar Sampada Study Area – Northern Arabian Sea (29th Nov. 2006 – 20th Dec. 2006) Participants National Institute of Oceanography, Regional centre, Kochi Central Marine Fisheries Research Institute, Kochi ________________________________________________________________________ Preliminary report of Cruise 251 Environment and Productivity patterns of Indian EEZ ________________________________________________________________________ LIST OF PARTICIPANTS OF CRUISE No.251 OF FORV SAGAR SAMPADA NIO-RC, KOCHI 1. Dr. Maheswari Nair - Chief Scientist 2. Mr. Muraleedharan K.R - Project Assistant III 3. Mrs. Jasmine.P - Project Assistant III 4. Mrs. Asha Devi C.R. - Project Assistant III 5. Ms. Jayalakshmi.K.J - Senior Research Fellow 6. Ms. Vineetha Gopinath - Project Assistant III 7. Mr. Mathew Paul - Project Assistant III 8. Mr. Saneesh.A.V - Project Assistant III CMFRI 9. Mr. Anoop.A.Krishnan - Research Fellow CMLRE 10. Mr. Renjan K.A. 11. Mr. sunil Kumar K.R. - Fishing Master - Fishing Hand 12. Mr. Pradeep Kumar - Fishing Hand 13. Mr. Binoy V - Fishing Hand M/s. NPL 14. Mr. Benny.J.Panakkal - Service Engineer 15. Mr. Mebish Mathew - Service Engineer 16. Mr. Sumesh T.T - Service Engineer 17. Mr.Renjith Jose - Service Engineer ________________________________________________________________________ Preliminary report of Cruise 251 Environment and Productivity patterns of Indian EEZ ________________________________________________________________________ Objectives Collection of data on environmental & productivity studies and Survey of marine Mammals Physical 1. Collection of CTD data up to 1000 m 2. Collection of Surface Met data 3. ADCP Chemical 1. Dissolved Oxygen 2. Nutrients Biological 1. Primary Productivity Studies 2. Secondary Productivity Studies 3. Microzooplankton studies 4. Marine mammals ________________________________________________________________________ Preliminary report of Cruise 251 Environment and Productivity patterns of Indian EEZ ________________________________________________________________________ Cruise Track – 251 (Northern Arabian Sea) Environment and Productivity patterns of Indian EEZ Fig.1 Map showing the Station position of cruise 251 during winter monsoon in the Arabian Sea overlaid on bathymetric chart. ________________________________________________________________________ Preliminary report of Cruise 251 Environment and Productivity patterns of Indian EEZ ________________________________________________________________________ INTRODUCTION The cruise 251 of FORV Sagar Sampada was focused on the study of Environment and Productivity patterns, in the early phase of winter cooling in the Arabian Sea (Nov. – Dec. 2006). In addition, survey of Marine Mammals was also carried out as a part of studies conducted by Central Marine Fisheries Research Institute. This cruise started on 29th November from Mangalore with an aim of covering 21 stations in the northern 4 transects (21ºN, 19ºN, 17ºN and 15ºN) under MR-LR programme. CTD was operated at all the stations and water samples from standard depths were collected for the study of Physical, Chemical and Biological parameters. Primary productivity studies were carried out at 7 stations by insitu incubation (Mooring) and 1 station by deck incubation. Multiple Plankton Net (MPN) and Bongo nets were operated at all stations to get the vertical and transverse profile of the zooplankton abundance. Physical Oceanography Mr. Muraleedharan K.R and Mr. Saneesh A.V National Institute of Oceanography, Kochi. During the cruise 251, twenty stations were sampled in four transects. The major objective of this cruise was to study the environmental processes in the northern Arabian Sea during early phase of the winter monsoon. Eighty-one CTD castings were carried out in a spatio-temporal scale and recorded raw data, were processed with a bin average of 1m depth to an ASCII formatted output. Mixed layer depth was calculated according to a depth at which temperature of 0.5°C drop from SST. Thermocline was taken at a depth where temperature shows 15°C. Surface meteorological parameters including SST were measured manually and compared with the data from automated Integrated Data ________________________________________________________________________ Preliminary report of Cruise 251 Environment and Productivity patterns of Indian EEZ ________________________________________________________________________ Acquisition Software (IDAS). The salinity values from the CTD were corrected against the values obtained from the ship borne Autosal (Guild line 8400b). ADCP (Acoustic Doppler Current Profiler 153 KHz) was operated throughout the cruise and the data was recorded at a bin size of 8m according to station wise (stationary) and station to station (running) mode. 22 India 21 1018 20 1016 Latitude (°N) 19 1014 18 17 1012 16 1010 15 10 m/s 1008 14 66 67 68 69 70 71 72 73 74 75 76 77 78 Longitude (°E) Fig.2 showing north south variation in the barometric pressure (shaded) with an overlay of SST (contour) and super impose by wind vectors (arrow) ________________________________________________________________________ Preliminary report of Cruise 251 Environment and Productivity patterns of Indian EEZ ________________________________________________________________________ 70 Depth (m) 60 50 40 30 MLD Coastal MLD Open 20 15 17 19 21 Latitude (°N) Fig.3 showing mixed layer depth variation in the coastal (200m) and open ocean area Salient features Maximum Sea Surface Temperature (SST) of 29.3°C was observed at coastal station of the Goa transect and minimum of 25.7°C was observed off Veravel transect. Atmospheric Pressure (AP) showed a north - south gradient in the study area. Lowest AP of 1009.8 mb was recorded in the southern stations and high AP of 1017 mb was recorded at northern stations. North- northwesterly wind with an average speed of 5.3 m/s prevailed over the study area. Shallow Mixed Layer Depth (MLD) of 29 m was observed at coastal stations (200 m) of all transects and a deep MLD was observed at all open ocean stations. Sea Surface Salinity showed maximum value of 36.62 psu in the open ocean waters (max at northern stations) and minimum of 34.72 psu in the coastal waters. ________________________________________________________________________ Preliminary report of Cruise 251 Environment and Productivity patterns of Indian EEZ ________________________________________________________________________ Average humidity observed during the cruise was 61% and least humidity was observed at Veravel and Mumbai transect. Chemical Oceanography Dr Maheswari Nair and Mr Mathew Paul National Institute of Oceanography, Kochi During the cruise 251, twenty stations were sampled in four transects. A total of about 283 samples were colleted from standard depths (0, 10, 20, 30, 50, 75, 100, 150, 200, 300, 500, 750 and 1000 m). Samples for dissolved oxygen were immediately fixed with Winkler A and Winkler B reagents and subsequently analyzed onboard using titration method (Dosimat model 665) after calibration. pH was estimated using WTW pH Meter after calibrating using buffer standards of pH 7 and 10. Nutrients (Nitrate, Nitrite, Phosphate and Silicate) were analyzed by using the segmented flow Auto Analyser (SKALAR) onboard after calibration using appropriate standards and following standard procedures. Salient features Dissolved Oxygen showed higher concentrations (<212 µM) in the surface waters of all transects and this is followed by an intense oxygen deficiency in the intermediate layers (150-1000m) with DO concentrations as low as 5.45 µM. The pH values in all transect ranged from 8.40 to 7.73 with maximum values observed in surface well mixed waters (0 to 50m) followed by minimum values in deeper layers. Low concentration of nutrients was observed in the surface waters (050m) of all transects followed by an increase in the concentration at intermediate depths reaching higher values at 1000m (nitrate~48 µM, phosphate~4.46 µM, silicate~ 65 µM). ________________________________________________________________________ Preliminary report of Cruise 251 Environment and Productivity patterns of Indian EEZ ________________________________________________________________________ Biological Oceanography Mrs. C.R. Ashadevi, Miss .K.J Jayalakshmi Mrs. P. Jasmine & Miss. Vineetha Gopinath National Institute of Oceanography, Regional centre, Kochi. Primary productivity studies Primary productivity measurements were carried out at all transects (4), at inshore and (4) offshore stations (total eight: 7 In - situ and 1 Deck incubation). 14C technique was used for the productivity studies by incubating the samples from sunrise to sunset from seven discrete depths (surface, 10, 20, 50, 75, 100 & 120 meters). After inoculating the sample with 1 ml of NaH14CO3 (activity 5 µC) the light and dark bottles were kept for insitu incubation for 12 hrs. After filtering the samples through 47 mm Whatman GF/F filters (0.7 µm) and the filters were exposed to HCl fumes to remove inorganic carbon and kept in scintillation vials (8 ml) for later isotopic analysis at the shore lab. For the estimation of chlorophyll a, one-litre of seawater was collected upto 75m from all stations and upto 120m from all PP stations, was filtered through 47 mm Whatman GF/F (with a few drops of MgCO3), and kept in the refrigerator for further analysis. For the estimation of Particulate Organic Carbon 1 litre of seawater (seven depths) was filtered from all the PP staions and the filters were stored in freezer till its analysis in shore lab. Collection of Phytoplankton 250 ml of seawater was collected from each of the 7 depths at the PP stations using CTD rosette sampler and preserved in Lugol’s Iodine solution. The qualitative and quantitative study of the Phytoplankton will be carried out at the shore lab. Collection of Microzooplankton ________________________________________________________________________ Preliminary report of Cruise 251 Environment and Productivity patterns of Indian EEZ ________________________________________________________________________ 8 litre of seawater was collected using CTD from the 7 depths at each of the PP stations and sieved through 20 µm mesh and preserved in Lugol’s iodine solution, to be analysed at the shore laboratory. Secondary productivity studies Zooplankton samples were collected from all stations by using Multiple Plankton Closing Net (Hydro bios) and Bongo Net. Bongo net was operated horizontally for 10 minutes at 2 knots ship speed at all stations for the collection of zooplankton especially for fish eggs and larvae. After the measurement of live biomass, zooplankton samples were preserved in 4% formalin-seawater. MPN (mesh size 200 micron and mouth area 0.25 m2) was used for the stratified sampling of zooplankton from five different standard water columns (0 – TT, TT – BT, BT – 300, 300 – 500 and 500 – 1000m). The hauling speed of MPN was limited to one meter per second. After the measurement of live biomass, the zooplankton samples were preserved in 4 % formalin-seawater. ________________________________________________________________________ Preliminary report of Cruise 251 Environment and Productivity patterns of Indian EEZ ________________________________________________________________________ Biomass (ml/m-3) 22 21 20 Latitude (°N) 19 18 17 16 15 14 66 67 68 69 70 71 72 73 74 75 76 77 78 Longitude (°E) Fig.4 showing the mesozooplankton biomass (ml.m-3) in the mixed layer of Northern Arabian Sea during the cruise. Salient features Highest mesozooplankton biomass was observed in the mixed layer of the offshore stations than the coastal stations. In the offshore regions maximum biomass (1.33ml.m-3) was observed at 21°N 67°E ( Stn. 1928 B). ________________________________________________________________________ Preliminary report of Cruise 251 Environment and Productivity patterns of Indian EEZ ________________________________________________________________________ Among the coastal stations, the maximum biomass (0.73ml.m -3) was observed at 21°N & 69°E (Stn. 1926) followed by coastal station (Stn. 1921) of 19° N The lowest biomass (0.109ml.m-3) was seen at the coastal station of 15°N (Stn. 1911B) Northern transects (21° and 19°N ) showed high mesozooplankton biomass than the southern transects (15 and 17°N) Issac - Kidd Mid water Trawl operation IKMT was operated at offshore stations of 15° and 17°N transects. The operation was carried out for 30 minutes duration with a ship speed of 2 knots. Major composition of the sample was eel larvae (11 ml.m-3) and euphausiids (7ml.m-3). Marine mammals observation ANOOP. A. KRISHNAN RESEARCH FELLOW, CMFRI. The study on the geographical distribution of cetaceans is taken as an objective during the present Cruise 251 along the west coast of India. As a part of survey on cetaceans following work were carried out. Sightings and photography of whales, dolphins and porpoises. Recording of hydrographical and meteorological data’s from the region of cetaceans sightings. Studies were carried along the west coast of India (Arabian Sea) from Mangalore to Veravel and back to Kochi. Continuous watch (6.00 – 18.00 hrs) of cetaceans was carried out mainly from the bridge of the vessel. A binocular and ________________________________________________________________________ Preliminary report of Cruise 251 Environment and Productivity patterns of Indian EEZ ________________________________________________________________________ Nikon F 80 wide angle zoom camera were employed to observe and capture appearance of cetaceans in the form of spouts, dorsal fin, upper body, flipper, flukes and body coloration whenever possible. Only if the species of a whale or dolphin is unmistakably identified based on the reported description, its name is recorded. In case there was a doubt the species name was mentioned, accompanied by “possible”. All others were treated as “unidentified”. Exact location of cetacean sighted along with the general hydrographical (CTD) and meteorological data (AWS) and a detailed description (to the possible extent) along with the numbers were recorded. With the help of these data, the species identity could be ratified in the future. A total of 90 dolphins were sighted in the area between 10°N to 21° N latitude and 66° to 74° E longitudes during the present cruise. Altogether 6 sightings were done and 94% of the sighted cetaceans could be unmistakably “identified”, while the remaining was “unidentified”. Photos have been taken wherever possible and would certainly lead to identification up to genus or species level once other expertise are sought for ratification based on detailed description. Around 99% of the sighted cetaceans were dolphins while remaining was whales. The species that were identified in the cruise were (identified) Stenella longirostris (Spinner dolphin) and (possible) Delphinus delphis (Common dolphin). The whale sighted off Goa could not be identified. During this cruise abundance of deep Ocean dolphins were prominent mostly off Ratnagiri. As the survey was mostly along deeper waters the cetacean distribution was scanty. ________________________________________________________________________ Preliminary report of Cruise 251 Environment and Productivity patterns of Indian EEZ ________________________________________________________________________ Fig. 5 Distribution of Marine mammals during cruise 251 Acknowledgements The chief scientist and the scientific team of cruise No. 251 are highly indebted to the Master Y Poojary and the crew of FORV Sagar Sampada for their cooperation rendered through out the cruise. Words of indebtedness are also due to the Fishing Master Mr. K.A Renjan and his associates, for their round the clock service rendered during the sampling operation. The technical support given by the Service Engineers of Norinco Pvt Ltd, Cochin is gratefully acknowledged. Chief Scientist Cruise 251 ________________________________________________________________________ Preliminary report of Cruise 251