Northwest Fisheries Science Center

The Main Deck

Acoustic and trawl adventures in the Northeast Pacific

This portal tracks the research and sea-going activities of the Fisheries Engineering and Acoustic Technologies (FEAT) Team from NOAA¿s Northwest Fisheries Science Center.  Follow us as we use acoustics, trawling, and oceanographic sampling to learn about the Northeast Pacific Ocean.

Back deck of Bell M. Shimada
Acoustic echogram of hake
trawl catch
 

Heading back to Newport

By Sandy Parker-Stetter, NWFSC
February 11, 2017


The NOAA Ship Bell M. Shimada is now steaming back to Newport. Two science parties have spent 30 days at sea evaluating the distribution and biology of Pacific hake (and coming up with more questions), but our sea time is up. The survey ends on 12 February.

2017 was the 2nd year of winter work, and this year was a different beast in terms of both hake distribution/densities and survey conditions. What fun would it be if 2017 was exactly like 2016? As with reading/writing, for this survey, “There is no real ending. It’s just the place where you stop the story.” (Frank Herbert)

map
A paper record of active survey design. Photo credit Parker-Stetter, NWFSC

What was accomplished during the 2017 survey?
We completed ~3,200 nautical miles (nmi) of acoustic data along transects. Eleven midwater trawls were done, with 10 of the trawls containing hake. Fifty-four casts were made with the Conductivity-Temperature-Depth (CTD) rosette to measure water properties, and zooplankton were collected at 25 of those locations. Water samples for eDNA (i.e. environmental DNA) were collected at 13 stations. Fish (or fish parts) were collected for collaborators working on topics ranging from aquaculture to genetics to toxicology. We redesigned, revised, improvised, and made decisions on the fly when needed. The paper map in the Acoustics Lab – decorated by proposed transects, stations, advice, and funny sci quotes – was always changing. 

How was 2017 different from 2016 (and why)?
We saw many dense layers of hake in 2016, but in 2017 the hake were harder to find and were in weaker (i.e. less dense) aggregations. Another interesting observation was that in 2016 hake were in the northern and middle portions of the survey area, but in 2017 they were predominantly in the middle and southern portions of the survey area. We can’t say for sure why 2016 and 2017 were different. Maybe some of the hake decided this year to go way offshore, or down to Mexico, for reasons that made sense in their hake-brains. It is possible that differences in conditions (e.g. temperature, salinity, currents), even if subtle to us, influenced the distribution and densities of hake. We’ll pick up these questions back on land as we start the harder part of our work, the analysis.

Were your science parties for legs 1 and 2 total rock stars?
Yes! Both legs 1 and 2 kept their humor no matter what, joined in on the speculation about where we would find hake, and pitched in to help with everything we did. What we accomplished this year, in spite of the weather, the uncooperative hake, and other factors plotting against us, is a testament to the dedication of the science parties. Even when tired, frustrated, or sick (not naming names, but I will remind *someone* that terrestrial birds are pretty interesting), the scis always kept me laughing and reminded me of why we do this crazy stuff. 

Thanks for following along during the at-sea portion of the 2017 Winter Hake Survey adventure. As possible, I’ll post on what we’re finding during the on-land part of our work.
 


Tagged: Hake, Acoustics, Winter hake research, FEAT, FRAM, Oceanography, Ecosystem, California Current Large Marine Ecosystem, CCLME, El Niño, La Niña, Climate

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July 2017
June 2017
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