MSc Aquatic Ecosystem Management 2004



Sustainable Catchment Management: comparing urbanised with semi-pristine catchments

Site Pictures 3: Creran Catchment - Loch Creran

Click on the thumbnails for a full-scale picture

Loch Creran is a fjordic loch formed as a result of glaciation, with 2 basins each with a sill at the entrance. This results in rapid tidal currents ofer the sill without disturbing the deeper waters, allowing stratification to occur.

We sailed on the SAMS research vessel Calanus to take samples of the water column.


This is the end of the outer basin where it leads to the inner basin: the boat was unable to sail into the inner basin.
The outer basin contains a number of fish and mussel farms
One of our sampling sites was near to this farm.
Part of the team assembled for action. At each sampling point the boat was stopped.

A plankton net was dropped through the water column and then raised to take an integrated sample of the plankton
The net being rinsed
The contents harvested

Sampling of the water was carried out using a CTD with sample bottles attached, which can be triggered to close independently as required
The CTD is lowered on a winch to predetermined depths
CTD refers to "conductivity, temperature, depth", which are the basic monitoring parameters it is designed for.
This one has been further modified to monitor dissolved oxygen (DO) and chlorophyll fluorescence (note the blue excitation light)

Water was collected from the bottles for DO measurement by titration and filtered for chlorophyll estimation
Next day, the DO was measured by the Winkler titration method, to calibrate the CTD sensor
The filters were extracted overnight in solvent, then the concentration of chlorophyll measured by spectrophotometry


Go to the Almond Catchment or river Creran