Page 1 CONSULTANCY AND RESEARCH IN AQUACULTURE AND THE AQUATIC ENVIRONMENT A Company in the NIVA-group Methodology for Environmental monitoring of aquaculture
Page 2 Environmental monitoring and modelling What information do we need? Physical parameters Chemical parameters Biological parameters Detailed survey of production in the area (area of pens and annual production) Historical data Collecting new data Predictive modelling of the areas Environmental data
Page 3 Survey for mapping the environmental condition Weather data wind direction, speed, temperature Bathymetry of the area Sea map information New mapping Tidal range and current speed, direction and dispersion Temperature, turbidity, salinity, oxygen, chlorophyll profile through the water column Water chemistry Sediment analysis (biological and chemical)
Page 4 Equipment required 2 Grab – freshwater Ekman grab and modified marine Van Veen grab 2 Sieve for the sieving the sediment samples 4 standard current meters – current and temp 2 enhanced current meters – current, temp, conductivity, oxygen, turbidity, depth CTD probe – conductivity, temperature, depth, chlorophyll, oxygen, turbidity 2 handheld Garmin GPS 2 handheld echo sounders Garmin GPS and echo sounder 2 portable computers Total value of US$ 100,000
Page 5 Bathymetry The bathymetry is done by using a Garmin echo-sounder which contains a GPS and a chart plotter (GPSmap 178C sounder) GPS store the tracks automatically tagged with the date and time of creation, as well as water temperature and depth It can be set up on a small boat It usually takes a full day to complete depending on the size of the area surveyed
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Page 7 Bathymetry
Page 8 Bathymetry and sediment type surveys (results)
Page 9 Bathymetry survey (results)
Page 10 Current meter deployments These measurements are made to measure the general hydrodynamic conditions at each site. The main factors of interest are: the distribution of the currents and the extremes measured at the site how current speed and direction are affected by wind conditions the use of these measurements in modelling the dispersion of wastes from the cages Two of the current meters have sensor that are measuring turbidity, conductivity, depth, oxygen
Page 11 Current meters deployment
Page 12 Current meter deployment A typical mooring current meters placed at 5m and 10m depths for areas with 20m deep at 3.5 and 7.5m depths for areas 15m deep Set up are often modified for site specific conditions Deployed for 24 hours to one month
Page 13 Equipment – Current meter
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Page 16 Downloading and processing data
Page 17 Current meter deployments (results) The plots show current speed and direction for a site measured over a one month period at the surface
Page 18 Plots from the current meters at different depths. Analysis will also give the current speed and direction distribution Current meter deployments (results)
Page 19 Current measurements in Bolinao
Page 20 Current measurements in Lake Taal – at 10 meters
Page 21 Oxygen and temperature in Lake Taal – at 10 meters
Page 22 Drifting buoy surveys (objectives) The level of water dispersion near a fish farm is an important factor as it determines how well wastes are dispersed and water bodies are reoxygenated. The main factors of interest are: how quickly released drifters spread out relative to one another How far apart the drifters have spread out at the end of the release period the measurement of unusual hydrodynamic conditions in the surrounding area
Page 23 Drifting buoy surveys (drogues) The drifting buoys are buoys marked with flags that are pulled along by subsurface water currents by sails. They are released in a group and their movement monitored
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Page 27 Drifting buoy surveys (results) An example of a release made from a cage group. The drifters show a clockwise circulation which would be difficult to measure with a single current meter mooring
Page 28 Turbidity and measurements Water depth is recorded when secci disc can no longer been seen
Page 29 Conductivity, Temperature and Dissolved oxygen (CTDO) The CTDO measures, calculates and records: Water salinity (conductivity) Temperature Oxygen level Turbidity Possibilities to make isoplets and profiles for the different parameters Also can add Chlorophyll
Page 30 Water column sampling by CTD
Page 31 Water column measurements CTD is dropped to the bottom (seabed) and retrieved slowly to the surface (records data every 5th second)
Page 32 Water column sampling Water column is sampled for dissolved oxygen, salinity and temperature
Page 33 CTD transect
Page 34 CTD transect
Page 35 Horizontal plot of oxygen in Lake Taal at 1 meter
Page 36 Horizontal plot of oxygen in Lake Taal at 2 meter
Page 37 Horizontal plot of oxygen in Lake Taal at 7 meter
Page 38 Horizontal plot of oxygen in Lake Taal at 20 meter
Page 39 CTD-profile in Lake Taal - April 2006
Page 40 Transects – vertical profiles in Bolinao Salinity, transect 1 Temperature, transect 1
Page 41 Water quality Water samples are taken and analyzed for parameters that relevant for measuring the environmental conditions chlorophyll-a ammonia nitrate nitrite phosphate
Page 42 Chlorophyll
Page 43 Sediment studies - sampling Samples or taken by grab
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Page 48 Sediments Larger particles are collected, preserved and stained
Page 49 High organic content - close to a fish cage Low organic content - far away from a fish cage
Page 50 Bolinao – station with bad conditions
Page 51 Bolinao – marine station with good conditions
Page 52 Grab movie
Page 53 Sediment sample analysis - taxonomy Samples are analysed for benthic diversity
Page 54 Sediments – chemical samples Samples are taken of the surface layer for chemical analysis (TOC, grain size, ++)
Page 55 Fish Farm registration The coordinates of every fish farm are recorded and note taken if operational