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 8, 2017
Science and Technology Log
The main scientific research being completed on the Reuben Lasker during this voyage is the Pelagic Juvenile Rockfish Recruitment and Ecosystem Assessment Survey and it drives the overall research on the ship during this voyage. Rockfish are an important commercial fishery for the West Coast. Maintaining healthy populations are critical to maintaining the fish as a sustainable resource. The samples harvested by the crew play an important role in establishing fishery regulations. However, there is more happening than simply counting rockfish here on the ship.
How does it work? Let me try to explain it a bit.
First, the ship will transfer to a specific location at sea they call a “Station.”
For a half hour prior to arrival, a science crew member will have been observing for Marine Mammals from the bridge area. When the station is reached, a new observer from the science crew will take over the watch outside on the deck. The fishermen on the boat crew will then unwind the net and launch it behind the boat. It must be monitored from the deck in order to ensure it is located 30 m below the surface. Once everything is set, then the ship trawls with the net at approximately 2 knots. Everything must be consistent from station to station, year to year in order to follow the standardized methods and allow the data recorded to be comparable. After the 15 minutes, then the crew pulls the net in and collects the sample from the net. This process is potentially dangerous, so safety is a priority. Science crew members can not go on the deck as they have not received the proper training.
Timelapse video of the fishermen bringing in a catch. 6/7/17 (No sound)
Once the sample is hauled in, the science personnel decide which method will be used to establish a representative sample. They pull out a sample that would most likely represent the whole catch in a smaller volume. Then we sort the catch by species. After completing the representative samples, they will eventually stop taking counts of the more abundant organisms, like krill. They will measure the volume of those creatures collected and extrapolate the total population collected by counting a smaller representative sample. Finally, we counted out all of the less abundant organisms, such as squid, lanternfish and, of course, rockfish. After the sample is collected and separated, Chief Scientist Sakuma collects all of the rockfish and prepares them for future investigations on shore.
A selection of species caught off the coast of San Clemente. These include Market Squid, Anchovies, Red Crab, King-of-Salmon (the long ribbonfish), and Butterfish, among others.
NOAA has used this platform as an opportunity. Having a ship like the Reuben Lasker, and the David Starr Jordan before that, collecting the samples as it does, creates a resource for furtAher investigations. During the trawls we have catalogued many other species. Some of the species we analyzed include Sanddab, Salp, Pyrosoma, Market Squid, Pacific Hake, Octopus, Blue Lanternfish, California Headlightfish and Blacktip Squid, among others. By plotting the biodiversity and comparing the levels we recorded with the historic values from the stations, we gain information about the overall health of the ecosystem.
What happens to the organisms we collect? Not all of the catch is dumped overboard. Often, we are placing select organisms in bags as specimens that will be delivered to various labs up and down the coast.
This is a tremendous resource for researchers, as there is really no way for many of these groups to retrieve samples on their own. Rachel Zuercher joined the crew during this survey in part to collect samples to aid in her research for her PhD.
Along with the general species analysis, the team specifically analyzes the abundance of specific krill species. Krill forms the base of the marine ecosystems in the pelagic zone. They are a major food source for many species, from fish to whales. However, different krill species are favored by different consumers. Therefore, an extension of the Ecosystem Assessment involves determining the abundance of specific krill species. Thomas Adams has been responsible for further analyzing the krill collected. He counts out the representative sample and use microscopes to identify the species collected based on their physical characteristics.
Additionally, at most stations a Conductivity, Temperature and Depth cast (CTD) is conducted. Basically, bottles are sent overboard and are opened at a specified depth.
Then they are collected and the contents are analyzed. Often these happen during the day prior to the Night Shift taking over, with final analysis taking place after the cruise is complete. This data is then connected with the catch numbers to further the analysis. Ken Baltz, an oceanographer on the ship, uses this information to determine the production of the phytoplankton based on the amounts of chlorophyll detected at depth. This is an important part of the food web and by adding in this component, it makes the picture below the surface clearer.
Finally, there are two more scientific investigations running as we cruise the open seas during the daylight hours. Michael Pierce is a birdwatcher from the Farallon Institute for Advanced Ecosystem Research who is conducting a transect survey of Seabirds and Marine Mammals. He is based on the Flying Bridge and catalogs any birds or marine mammals that pass within 300 meters of the ship’s bow. Although difficult, this study attempts to create a standardized method for data collection of this nature. As he explained, birds are more perceptive than we are – what looks like open ocean really varies in terms of temperature, salinity and diversity below the surface. Therefore, birds tend to favor certain areas over others. These are also important components of the food web as they represent upper level predators that are not collected in the trawl net. Also, on the bottom of the ship transducers are installed that are able to gather information through the EK60 Echosounder. This sonar can accurately identify krill populations and schools of fish underwater. Again, adding the data collected from these surveys help create a much more complete understanding of the food web we are analyzing out on the open sea.
Personal Log
Sunday, June 4
The waves were very active all day. Boy am I glad I’m wearing the patch. There was so much wind and the waves were so high, there was a question if we were even going to send the net out. High wind and waves obviously add an element of concern, especially for the safety of the boat crew working the net.
I spent some of the day up on the Bridge- the section of the boat with all of the navigation equipment. The Executive Officer (XO) gave me an impromptu lesson about using the map for navigation. They have state-of-the-art navigation equipment, but they also run a backup completed by hand and using a compass and straightedge just like you would in math class. Of note – the Dungeness Crab season is wrapping up and many fishermen leave traps in the water to catch them. When the boat is passing through one of these areas, someone will act like a spotter so the boat can avoid getting tangled up. When I was looking with him, we saw some whale plumes in the distance.
We did launch the net twice Sunday night, collecting a TON of krill each time. In the first batch, we also caught some squid and other small prey species. The second trawl was very surprising. Despite cutting it down to a 5 minute trawl, we caught about the same amount of krill. We also caught more squid and a lot of young salmon who were probably feeding on the krill.
Monday, June 5
I am getting used to the hours now – and do not feel as guilty sleeping past 2PM considering we are up past 6 in the morning. It will make for a tricky transition back to “the real world” when I go home to NY!
During the day, spent some time just talking with the science folks and learning about the various tasks being completed. I also spent some time up on the Flying Bridge as they said they had seen some Mola, or Giant Ocean Sunfish (although I did not see them). I did have a chance to make a few videos to send to my son Aiden’s 3rd grade teacher back in NY. It did not work out as well as I had hoped, but considering we are out in the middle of the ocean, I really can’t complain about spotty wi-fi.
Once we started the night shift, we really had a good night. We completed work at 5 stations – which takes a lot of time. We saw a LOT of biodiversity last night – easily doubling if not tripling our juvenile rockfish count. We also saw a huge variety of other juvenile fish and invertebrates over the course of the night. We finally wrapped up at 6:30 AM, what a night!
Tuesday, June 6th
We found out today that we will need to dock the ship prematurely. There is a mechanical issue that needs attention. We are en route straight through to San Diego, so no fishing tonight. However, our timing will not allow us to reach port during the day, so we will get a chance to sample the southernmost stations Wednesday night. Thus is life at sea. The science crew is staying on schedule as we, hopefully, will be back on the water this weekend.
Wednesday, June 7th
After a day travelling to San Diego, we stopped at the stations near San Clemente to collect samples. Being much farther south than before, we saw some new species – red crabs, sardines and A LOT of anchovies. Closer to shore, these counts dropped significantly and krill showed up in numbers not seen in the deeper trawl. Again, I am amazed by the differences we see in only a short distance.
More from our anchovy haul- the bucket contains the entire catch from our second trawl, the tray shows how we analyzed a subset. Also on the tray you find Red Crab, Salps, Mexican Lanternfish and Krill.