Saturday, July 4, 2009
We are heading north in search of winds, without much luck still. The nice thing about heading north-each day the sun seems to set a little later. Who can complain about more daylight?
This morning we deployed the 11th Manta trawl of the trip. This sample contained far more plastic than any of the past 10. We are deploying another trawl this evening in order to capture the mesopelagic fish which feed on the surface at night. We also are discussing doing early morning trawls (around 4 am or so) in order to catch these fish after they had fed. This may yield a more accurate plastic ingestion count, since we might be able catch the fish before they pass any plastic they ingested. In addition it would be interesting to see if there is a difference in the quantity of plastic pulled up after marine organisms have been feeding throughout the night.
The afternoon was spent watching for debris off the foredeck. Along with several fragments of plastic, we found a large polystyrene buoy, under which a school of Mahi Mahi had taken residence. After disturbing the shelter of the fish, they scattered frantically-right into one of the lines we had trailing behind the boat. Christiana worked up the fish and found a possible plastic particle in its stomach which has been preserved for on shore lab analysis. She also noticed that this female had completely hydrated gonads. This means she was ready to spawn, but the odd thing is that Mahi typically spawn in the springtime. She was the 11th Mahi we have caught so far (and we have still only pulled in one male!) She was also heaviest and the longest (jackpot!).
RESPONSE TO COMMENTS
We do have a rough running count of the larger pieces of debris we have collected so far-approximately 45 or so. We have spotted much more than this, but this was all we were able to get our hands on (much of the time, the debris is too far for us to net from the boat or we are in transit and cannot slow down or maneuver in time to catch it). And this is also including the plastic we have accumulated from the trawls-these are the tiny fragments which we will not be able to quantify and classify until we get them back to the lab. And not to worry-more will be heard from the resident fish nerd!