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August 26, 2013

South Nehalem Reef


We awoke this morning to calm seas and a beautiful sunrise coming up over Cape Lookout, Oregon.  Knowing it would be the last land we’d see for the next six days, we motored offshore for three hours and arrived at South Nehalem Reef; over 20 miles off the coast.  Getting the ROV set up, our deployment and retrieval operations had already started becoming second nature.  Attracted by the only vessel in sight, hundreds of seabirds flocked to the vessel.  They are probably accustomed to getting a fisherman’s scraps or bycatch tossed overboard.  We were joined by albatross, sooty shearwaters, storm petrels, several species of gulls, and our favorites; tufted puffins.  But the only thing we were sending over the side of the Miss Linda was our remotely operated vehicle (ROV).

We chose South Nehalem Reef because new seafloor mapping data showed that it had extensive hard substrate.  This is a new piece of habitat data not previously available. When the ROV arrived at the bottom, about 500 feet deep, what we first saw instead appeared to be a flat silt plain.  Looking closely we saw sea whips, sea pens, flatfish and one large ray hiding in the mud.  All of a sudden we came upon a six foot high wall with rockfish, sponge, fern like crinoids and multiple types of gorgonian corals.  We quickly brought up the ROV to avoid tangling in the rocks.  Descending back down to the top of the reef we saw canary rockfish and rosy rockfish, and other fishes hanging in the interface between the high relief rock and the flat fields covered with thick silt.  Our last dive, however, was relatively stark and it has possibly been trawled, with signs of linear trenches in the seafloor and few of the structure forming invertebrates we hoped to find.  Looking back on shrimp trawl data we have, there appeared to be some historic trawling in this area.  While a barren seafloor is a stark contrast to the other vibrant areas we dove on, it is a strong reminder of how fragile marine life is, and how even a single pass of a trawl can have lasting impacts.