dinsdag 22 maart 2016
Once More into the Breach
Welcome to the webblog for the Dutch contribution to the International Blue Whiting Spawning Stock Survey 2016, an international collaboration between Norway, the Faroese Islands and several EU countries. Unfortunately, Russia is not participating in this year's survey.
We are aboard the RV Tridens, which departed from Galway in the early hours on Monday 21st of March. You can track the vessel here:
The seas were remarkably calm throughout Monday. We reached our first station (GPS position at which we begin our transect or take measurements), near the continental shelf edge at the Porcupine Bank, at about 7 p.m. and began the acoustic transect work. Here is an example of an echogram we recorded.
Acoustics is a scientific means of detecting and measuring the changes of density in a medium (in this case sea water) using sound. Since fish are more dense than water, they are readily distinguished in the water column. It makes for a powerful, non-invasive method to estimate stock abundance and biomass of large schools of fish. To verify the acoustic readings, we will be doing fishery analysis via trawl net.
In the meantime, we had a look at the local birds. They were predominantly gannets, black-headed gulls, fulmars and a few blackbacked gulls.
The sea is a little rougher today with an area of low pressure coming towards us.
We are currently about three quarters into our second transect, no sight of large whiting schools yet, hopefully this evening. Lots of sea to cover.