David Amidon: The Night Shift, June 4, 2017


NOAA Teacher at Sea

David Amidon

Aboard NOAA Ship Reuben Lasker

June 2 – 13, 2017

Mission: Pelagic Juvenile Rockfish Recruitment and Ecosystem Assessment Survey

Geographic Area of Cruise: Pacific Ocean off the California Coast

Date: June 4, 2017

 

Science and Technology Log

All of the work for the Juvenile Rockfish Survey is completed at night – we probably will not even get going  most nights until after 9 PM. Wonder why so late? Any guesses?

This is a night time operation because we are focused on collecting prey species – we are not catching full grown rockfish, only juveniles which are less than a years old (YOY = Young of the Year). As Keith Sakuma, the Chief Scientist for the Reuben Lasker, explained – this survey gathers information about the juvenile rockfish so that NOAA can pass information onto the states in order to establish a sustainable fishery. This could lead to changes in fishing regulations based on the abundance of the juvenile stocks, which would be adults down the road. They trawl at night for two main reasons- during the day time, the rockfish would simply see the net and swim away. Also, many of the other creatures being catalogued are prey species that hide in the depths during the day to avoid predators, rising to the surface as the night moves on.

The night shift includes the science personnel and the crew of the boat. The boat crew not only operates the ship, but the fisherman also send out the trawl net and bring it back in. While the boat crew rotates on a specified schedule, the night-time science group keeps going until the work is done. However, these two groups are very much in sync and really work well together.  This blog entry will be my introduction into the procedures and initial results of our work from the first couple nights. I will provide much more detail in later posts.

The science personnel for this leg of the voyage includes myself and Chief Scientist Sakuma as well as Cherisa and Ryan, who are members of the NOAA Corps; Thomas, an undergrad student from Humboldt State; Rachel, a PhD student at UC-Santa Cruz; and Maya, a Hollings undergraduate scholar from UNC-Wilmington.

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The Night Crew at work separating species during the shrimp haul. Photo by Keith Sakuma.

The Juvenile Rockfish Survey, boiled to its simplest terms, consists of a midwater trawling net behind the ship, meaning it does not float and it never touches the bottom. Anything caught will be sorted and analyzed by the science crew. In reality, it is a bit more complicated.

First of all, net operations take place at specified stations that the ship revisits periodically and have been used for some time. The stations for a night run on the same latitude line, running west away from the coast.

Before sending the net out, we need to run a Marine Mammal Watch from the bridge for 30 minutes. If a marine mammal, such as a sea lion, dolphin or whale, is spotted, then they make efforts to avoid getting them tangled in their nets, or alter their behavior in any way. Sometimes the trawl for that station has to be abandoned due to wildlife activity, although we have not seen any marine mammals during our investigation so far.

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Getting ready for my shift on the Marine Mammal Watch

Once the ship arrives at a station, the boat crew sends out the net. After it reaches the depth of 30m, they trawl for a 15 minute interval. A science crew member is also sent outside on deck to continue the marine mammal watch for the duration of the trawl. Finally, after the time is up, they bring in the net and empty its contents into buckets, which are then transferred to the science crew.

This is when our work began. While we are on the lookout for rockfish, we actually found very few of these. A majority of our catch consisted of pyrosomes and krill. The science crew employed a number of measures to estimate the numbers of these creatures, as counting them one-by-one would have taken a long, long time to do. We did volume approximations and analysis of representative samples for these creatures. When we found fish or other species of note, we would pull the individuals out, classify them and record their lengths. Samples were frozen for use by researchers working at other locations on the West Coast.

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Measuring the mantle of a Market Squid. Photo by Rachel Zuercher.

Some examples of the species we collected:

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Juvenile Rockfish collected off the “Lost Coast”

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Sample of other species collected and catalogued, including: Medusa Fish, Gonatus Squid, Thetys and California Headlight Fish

We worked solid through four stations on the first night, wrapping up just before 6 AM. We will be at it again, if weather permits, every night of the voyage.

Personal Log

Thursday, June 1st

This was a very long day. I left my house in Syracuse, NY at 6 AM, flying out of the airport around 8 AM. After a quick transfer in Chicago, I flew in a Boeing 737 all the way to San Francisco. I then made it to Eureka, California around 4 PM (West Coast time) for an overnight stay. Fortunately, I met up a few of the science personnel for dinner who were also headed to the Reuben Lasker in the morning. Eureka was beautiful, surrounded by oceans and redwoods.

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Sunset in Eureka, CA

Friday, June 2nd

In the morning, we caught a transfer boat at the public marina out to the Reuben Lasker, anchored a few miles away off the coast. Once the passage was done, we settled in and met some of the crew. I even shared a coffee with the CO- or Commanding Officer. Everyone onboard has been so open and welcoming – you can tell they enjoy their work.

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Transfer boat that to us to the Reuben Lasker

After dinner, we finally got down to sciencing. (That’s my word – I’m sticking to it.) I was impressed by how different the catch was from each station, even though they are only a few miles apart. You can try to start telling a story right there. That’s kind of the point to this whole survey. To try to tell a story about the overall health of the pelagic ecosystem based on representative samples. Piece by piece, year by year, data points can turn into meaning when connections are made. I think it is science in the purest form -gathering data for the sake of having information. By having a long-term data base of information about all of the other creatures collected, not just the rockfish, we can decipher meaning by analyzing population trends and collating them with other phenomena, such as weather, fishing or pollution. 

Saturday, June 3rd

I am getting adjusted to the day/night pattern of the Night Shift. I got to sleep around 6:30 AM and woke up close to 2 PM. I was able to grab a quick cereal from the Galley and then started in on some work. Dinner was served at 5 PM – filet mignon with crab legs? The cooks, or stewards, Kathy & Patrick do an amazing job. They also save meals for people running the late schedule. For the next week and change, lunch is served around midnight and breakfast will be close to 6 AM, before we head to sleep.

Today, the wind picked up and the waves kicked up with it. We cruised around the “Lost Coast” and ran two stations at night. We were scheduled for more, but the waves got larger the further the ship is off the coast. Today’s word is shrimp – we hauled in more shrimp than you could count. We also found a number of rockfish in one of the stations, although there were very few found in our second trawl.

Did You Know?

… that there are over 85 species of krill?

http://www.krillfacts.org/1-krill-facts-center.html

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