Sand waves and some luck

We crossed the Great South Channel and started working on Georges Bank on Wednesday afternoon (August 15).  We are being blessed with excellent weather for working in this region, notorious for its rough seas, shoal areas and lack of any shelter from approaching storms.  Even in calm seas there is drama below the surface when working the shoal areas.  Last night we encountered an area of tremendous sand waves at station 30-7 which is located squarely in the shoal area of Georges Bank.  We were very lucky and missed having our bongo nets hit a 20-meter-high sand wave  (about 65 feet high, and one of several) by just a few minutes!  Instead we not only missed the sand, but were able to catch a tiny juvenile lobster about 15 mm long.  The station before that one, also on the shoals, had juvenile windowpane flounder and silver hake.  The flounder juveniles were up to 40 mm and the silver hake up to 50 mm in length.  All of these animals were caught using only our 61 cm diameter bongo nets, since we finished our Isaacs-Kidd midwater trawls yesterday.

Isaacs-Kidd Midwater Trawl being hauled aboard the Henry Bigelow. (Photo by Jerry Prezioso, NEFSC/NOAA)

bong nets and CTD

Bongo nets and CTD unit being deployed from the Henry Bigelow. (Photo by Sammi Ocher, Northeastern University)

sammi washing net

Sammi Ocher, Northeastern University graduate student, washing a plankton sample from the bongo net. (Photo by Jerry Prezioso, NEFSC/NOAA)

As I am writing this on Friday afternoon (August 17)  we are in Canadian waters, on the northeast peak of Georges Bank, heading for a station in the Northeast Channel.  We’ll be working our way back west across the northern flank of Georges for the remainder of today and part of tomorrow, then proceed on into the Gulf of Maine, where we have until Thursday afternoon to finish sampling before returning home.

juvenile fish

Silver hake and windowpane flounder juveniles caught on Georges Bank in the bongo nets. The silver kake at the top of the photo is 50 mm long (roughly 2 inches), the windowpane flounder in the middle is 40 mm long (about an inch and a half). (Photo by Jerry Prezioso, NEFSC/NOAA)

 

juvenile lobster

A juvenile lobster caught on Georges Bank in the bongo net. It is about 15 mm long, or just over a half-inch. (Photo by Jerry Prezioso, NEFSC/NOAA)

Net tow and bottom profile showing the tow profile of a bongo net on the left (purple line), and a 20-meter-high sand wave that the bongo nets just missed, on the right (blue line). Screen capture by Senior Survey Tech Jim Burkitt, MOC-A, NOAA.

Time will be tight, but with our continuing good weather, and everything (and everyone!) working at full capacity, we have a good chance, I believe, to cover most of the Gulf of Maine area.

Jerry Prezioso
Chief Scientist
HB 12-05 EcomMn/CliVEC cruise

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