Respirometer on Board

By Ann Robertson, NOAA Fisheries, on the Northwest Explorer 

A new component of our Gulf of Alaska research this summer is the use of a respirometer on board the ship to measure the oxygen consumption (respiration rate) of fish. We had hoped to investigate the respiration rate of larval and age-0 rockfish. This is done by placing the fish in a closed chamber of oxygenated water, turning on a pump to recirculate the water, and watching the oxygen levels drop as the fish breathes. Unfortunately, only a few rockfish were collected, so we were only able to get a small amount of respirometry data. We were able to bring three small rockfish back to the lab in Juneau where we will continue our respirometry studies.

Our respirometer set up below deck on the Northwest Explorer. Plastic bags covering our electronic equipment prevented any moisture damage while at sea.

St John the Baptist Bay

By Jamal Moss, NOAA Fisheries, on the Northwest Explorer

After disappointing low catches of live age-0 rockfish in coastal waters, we decided to sample St. John the Baptist bay in Salisbury Sound, which is about 30 miles north of Sitka. This bay is a known nursery ground for juvenile sablefish and we thought we might find some rockfish there as well. Unfortunately we did not find either, but we did encounter numerous age-0 through age-3 pollock and herring.


Scientists sorting live age-0 pollock from older age classes                       St. John the Baptist Bay looking out on

                                                                                                                                          Salisbury Sound and the Gulf of Alaska in the distance