Karah Nazor: Cool Catch Highlights, June 2-7, 2019

NOAA Teacher at Sea

Karah Nazor

Aboard NOAA Ship Reuben Lasker

May 29 – June 7, 2019


Mission: Rockfish Recruitment & Ecosystem Assessment

Geographic Area: Central California Coast

Date: June 2-7, 2019

June 2, 2019 Game Plan and Trawling Line: 5 hauls in the Piedras Blancas Line near San Simeon, CA. Piedras Blancas is known for its Northern elephant seal colony, M. angustirostris. Hauls were conducted outside of the marine reserve and we did not encounter seals.

Catch Highlights: The night started off with excitement when Keith Sakuma brought in an Pacific electric ray, Torpedo californica, and we all got to see it up close before releasing.

Keith S and electric ray
Chief Scientist Keith Sakuma holding a Pacific electric ray, Torpedo californica

In Haul 3 we collected a pelagic octopus, Ocythoe tuberculata, shown below. Chromatophores in cephalapods, including squid, cuttlefish and octopus, are complex organs made up of both muscle and nerve and provide the ability for the animal to rapidly change its skin color in order to blend into the surrounding environment to avoid predation, communicate, or send a warning signal. It was impressive to watch the chromatophores at work as the pelagic octopus attempted to blend into the white background of his tank by turning white (see photos below) We released it back to the sea.

Pelagic octopus
Pelagic octopus (Ocythoe tuberculata) attempting to camouflage with the background and flashing white
Pelagic octopus chromatophores
Pelagic octopus (Ocythoe tuberculata) with chromatophores expressing orange, purples and pinks. The beak is exposed here.

The differences in skin coloration of the five primary squid species we are catching including Boreal Squid, Blacktip Squid, Unknown Squid, Gonadus Squid, and Market Squid (see image below) are noteworthy. While living market squid exhibit brown, pink and purple skin color (see image below) the Chiroteuthis squid tentacle displays orange and red chromatophores (see image below).

Common squids
Common squids in our catches. From top to bottom, Boreal Squid, Blacktip Squid, unknown species, Gonadus Squid, and Market Squid.
market squid
Living market squid exhibiting brown, pink and purple chromatophores.
chromatophores
Pink and purple chromatophores on the mantle of a market squid.
chromatophores
Orange and red chromatophores on a tentacle of the Chriroteuthis squid.

In Haul 4 we collected a Cranchia scabra, which Chief Scientist Keith Sakuma calls the “baseball squid” or glass squid whose body is covered with tubercles (brown spots on mantle in photo below). This animal attempted to hide from us by turning white, retracting its tentacles and inflating himself into a ball, somewhat resembling a baseball. After a few pictures, we released it back to the sea.

Cranchia scabra or "baseball squid"
Cranchia scabra or “baseball squid”

Another exciting deep-sea creature, the Pacific hatchet fish, Argyropelecus affinis, was collected in a bongo net deployed prior to CTD, for Dr. Kelly Goodwin’s eDNA research.  The fish we collected below still has intact blue scales due to being well preserved in the bongo. The hatchet fish lives in mesopelagic zone down to 2000 m depths where the CTD sensors recorded a temperature of four degrees Celsius! Hatchet fish have upward facing eyes and mouths and swim up to the the epi-pelagic zone at night to feed on salps and krill.

Pacific hatchet fish, Argyropelecus affinis
Pacific hatchet fish, Argyropelecus affinis

Kelly conducted a quick surface bucket dip prior to CTD deployment in which we found a small (~2 inch) siphonophore, which I was very excited about since this was my first one to ever see in person! Siphonophores are colonial Cnidarians composed of individual animals called zooids. Moss Landing Graduate Student Kristin Saksa and I were able to confirm the identification of this beautiful creature as a siphonophore using an invertebrate field guide that Keith Sakuma brought on board. Perhaps due to the temperature change from being in the sea to being observed in a cell culture dish under the microscope, the siphonophore broke apart into its individual zooids right in front of my eyes.  See before and after photos below.   

Intact Siphonophore colony
Intact Siphonophore colony from bucket dip, note tip or “hat” at the bottom on the animal.
individual siphonophore zooids
Siphonophore individual zooids appear as semi circles consisting of small brown semi-circles.

Tonight I was also able to observe living salps that were pulled up in the bongo net and take a video.  It was neat to see the salps pulsing.

Haul 5 was a massive haul full of pyrosomes, Pyrosoma atlanticum.  Kristin Saksa volunteered to stir the bucket of pyrosomes (using her arms) so that we could obtain an accurate distribution of organisms for the initial volume count and analysis.  As I video of this event (see stills from the video below), we were all laughing and realized that Kristin may be the only human on Earth who has ever stirred pyrosomes.

Kristin stirring pyrosomes
Kristin Saksa stirring a bucket full of Pyrosoma atlanticum
Kristin stirring pyrosomes
Kristin Saksa stirring a bucket full of Pyrosoma atlanticum

In haul 5 we were surprised to find a Giant 7-armed Atlantic octopus, or blob octopus. Keith Sakuma explained that the males have 7 arms as the fifth is a sex appendage whereas the female has 8 arms. After photographing this beautiful deep-sea octopus, we released him back to the sea.

blobtopus
Giant Seven-Armed Atlantic Octopus or “blob octopus”


June 3, 2019 Game Plan and Trawling Line: 5 hauls Outside Monterey Bay

Catch Highlights: Two of the hauls produced a lot of krill. The hauls had a high species density with a lot of myctophids, salps and blue lanternfish. Such hauls are time consuming to sort so as not to overlook something new and small. In one of the hauls we found a new-to-me myctophid called Nanobrachium. I dissected some of the fish and found that CA lanternfish and Northern anchovies were full of eggs, and their age/reproductive status was previously unknown.

A catch with a high krill count
A catch with a high krill count

We caught 2 young ocean sunfish, Mola mola.  Both were immediately returned to the sea.

Kaila with young Mola mola
Scripps Graduate Student Kaila Pearson with a young ocean sunfish, Mola mola.
Keith and mola mola
LTJG Keith Hanson with a young ocean sunfish, Mola mola.

We found several species of deep sea dragonfish which we arrayed below on a ruler. Most of these fish are less than 6 inches long, no bigger than a pencil, but they are equipped with sharp fangs and are apex predators in their realm! Dragonfish have large bioluminescent photophore organs underneath their eyes (and sometimes lining their bodies) which produce light and are used to attract or deter prey and attract mates.

dragonfish
All of the dragonfish caught on June 3, 2019 on the NOAA Ship Reuben Lasker.
more dragonfishes
Longfin dragonfish, Tactostoma macropus, on left and a Pacific black dragon, Idiacanthus antrostomus, on right. Also in the photo are a krill (on the left of the dragonfish) and a Gonatus Squid (top left corner of photo).
Longfin dragonfish, Tactostoma macropus, with large photo organ underneath the eye

We collected a stoplight loosejaw, Malacosteus niger, which can unhinge its jaw in order to consume large prey.

Stoplight loosejaw
Stoplight loosejaw, Malacosteus niger.
Face of stoplight loosejaw
Face of stoplight loosejaw, Malacosteus niger.


June 4th: Davenport Line

The highlight of today was at 5:45 P.M.  when team red hats went to the flying bridge for our workout and to hang out with Ornithologist Brian Hoover.  There was a lot of Humpback whale activity. I counted around 20 spouts. We observed one whale that flapped its tail against the sea surface around 45 times in a row, perhaps communicating to nearby whales by generating pulses in the water or creating a visual cue.  We saw several full breaches. We finished up the Davenport Line at 6:00 AM as the sea became rough. Thanks goodness for handrails in the shower.

The sorting team
The sorting team, aka Team Red Hats. From left: Kristin Saksa, Flora Cordoleani, Karah Nazor, Ily Iglesias, and Kaila Pearson.


June 5th: Outside of Tomales Bay

I woke up at 4PM and headed to the galley for dinner at 5PM.  The boat was rocking so much that I became dizzy and knew that I would become sick if I tried to eat dinner, so I headed straight back to bed. Around 9PM the sea seemed to have calmed a bit, but I soon learned that it only felt calmer because the ship was traveling in the same direction as the swell at the moment but that we were about to turn around.  Due to the rough conditions, the first haul inshore at Tomales Bay was delayed until midnight so the fish sorting team decided to watch “Mary Poppins Returns” in the galley. The talented chefs of the Reuben Lasker made the most amazing almond cookies today and, thankfully, temped me to eat again.  

Catch Highlights: Haul 1 at station 165 was one of the easiest and most exciting catches of the survey so far because we collected a lot of jellyfish – my favorite! We counted 66 West Coast sea nettles, Chrysora fuscescens, seven Northern anchovies (7) and 24 market squid. I actually have a tattoo of West Coast sea nettle on my ankle. We placed the jellyfish flat on the lab bench and quickly measured their bell diameter before returning them to the sea. They did not sting us as most of the nematocysts were likely triggered during haul in.  I removed a rhopalia, a sensory structure that lines the margin of the bell of Syphozoans (the “true” jellyfish). West Coast sea nettles have eight rhopalium which house the the ocelli (light sensing organ) and statolith (gravity sensing organ). A photomicrograph I took of the rhopalia under the dissecting microscope is below.

Karah measures sea nettle
Teacher at Sea Karah Nazor measuring a West Coast sea nettle Chrysora fuscescens.
Karah examines sea nettle
Karah Nazor examining a West Coast sea nettle, Chrysora fuscescens.
Kaila holds up sea nettle
Scripps graduate student Kaila Pearson examining a West Coast sea nettle, Chrysora fuscescens.
Kristin holds up a sea nettle
Moss Landing graduate student Kristin Saksa examining a West Coast sea nettle, Chrysora fuscescens.
light sensing organ
Photomicrograph of the ocelli or light sensing organ in the rhopalia of a West Coast sea nettle, Chrysora fuscescens.

Haul 2 mostly consisted of Northern anchovies, 1 krill, a few moon jellyfish, Aurelia aurita, a few squid, which made for another very short and easy sort (see photo below). I study moon jellyfish in my lab back at McCallie High School, so I was curious to look inside of the stomach and reproductive organs of these wild jellyfish. Under the dissecting microscope, eggs were present and were purple in color (see photomicrograph below).

jellyfish eggs
Photomicrograph of purple eggs and clear gastric filaments of the moon jellyfish, Aurelia aurita
sorting Haul 2
Kaila Pearson (left) and Karah Nazor and Keith Hanson sorting Haul 2.

Haul 3 had a lot of krill, young of year (YOY) Pacific hake, Merluccius productus, one large hake, and a few market squid. This sort was also super easy except for separating the small YOY Pacific hake from the krill.

Sorting of haul 3 which had a lot of krill and young of year (YOY) Pacific hake, Merluccius productus.


June 6th: Outside Farallones. On our final night, we conducted three hauls with very small harvests consisting of few organisms and low species density.  One new to me fish in the final catch was a top smelt fish (see image below). These were the three easiest sorts of the survey. It was suggested by Keith Sakuma that the catches were small due to the stormy conditions.

catch from the last night
A small catch from the last night June 6, 2019, with one West Coast Sea Nettle, a Gonatus squid, and two topsmelt silversides, Atherinops affinis.
Kristin with a topsmelt
Moss Landing graduate student Kristin Saksa with a topsmelt silverside, Atherinops affinis, from the final haul of the survey.


June 7, 2019: Return to San Francisco

Group photo at Golden Gate Bridge
In front of the Golden Gate Bridge at the conclusion of the cruise. From left: Brian Hoover, Kelly Goodwin, Ily Iglesias, Karah Nazor, Flora Cordoleani, Kristin Saksa, Lauren Valentino, and Jarrod Santora.
group photo at Marin Headlands
In front of the Marin Headlands at the conclusion of the cruise. From left: Ily Iglesias, Kristin Saksa, Flora Cordoleani, Kaila Pearson, Lauren Valentino, and Karah Nazor.

Karah Nazor: Sorting Protocol and the Ubiquitous Tunicates of the Central CA Coast: Salps and Pyrosomes, May 30, 2019

NOAA Teacher at Sea

Karah Nazor

Aboard NOAA Ship Reuben Lasker

May 29 – June 7, 2019


Mission: Rockfish Recruitment & Ecosystem Assessment

Geographic Area: Central California Coast

Date: May 30, 2019

Last night I fell asleep, twice, at the lab bench in between trawls, since I am still adjusting to being on the night shift.  We worked from 9:00 P.M. to 6:30 A.M. After the shift I had a nice hot shower and slept a solid 9 hours from 7:00 AM to 4:00 PM.  Hopefully, I will be less drowsy tonight!

Upon waking, I went to the galley and grabbed some Raisin Bran and coffee and took it up to the flying bridge to hang out with Ornithologist Brian Hoover.  Our current location is in the middle of the Channel Islands, an area I know something about because my friend Evan Morrison, mentioned in my first blog, helps with the Channel Islands Swimming Association, and I would like to swim between these islands one day.  Lauren Valentino, Flora Cordoleani, Ily Iglesias and I congregated on the flying bridge and decided we should exercise. We joined Flora in her squat challenge (80 squats on this particular day), followed by 5 minutes of planking and a bit of erging.  Half of female members of the fish sorting team are avid rock climbers. They did lots of pull-ups using the rock ring climbing training holds that are installed there.

It felt nice and warm when the ship stopped for deployment of the Conductivity, Temperature and Depth (CTD) Rosette, and it got chilly again as the wind picked up when the ship started moving again. We saw a few whale spouts in the distance and at 5:30 P.M. we went down to the galley for a delicious meal of steak and mashed potatoes.  I am beginning to really appreciate how nice this whole experience has been in terms of amenities. The NOAA Reuben Lasker first set launch in 2014 and is a state of the art fisheries vessel with a sophisticated acoustics lab, fish lab, dynamic positioning system, CTD, etc., but is ALSO equipped with creature comforts including a movie lounge, an ice cream cooler loaded with ice cream sandwiches, snickers, fruit pops, you name it, and my personal favorite – a coffee bar where all coffee is freshly ground, an espresso machine, and all varieties of milk and creamers, including Reese’s cup whipped cream. The mattress in my stateroom bunk is quite comfortable and the shower gets hot within seconds! I doubt it can get much better than this for a research experience at sea?

Game Plan and Trawling Line: Point Sal line with five 15 minute hauls.

I am familiar with the sorting protocol now. The catch is dropped from the net into the bucket by members of the deck crew and survey tech, with the oversight of Keith Sakuma, Chief Scientist and NOAA Operations Officer Keith Hanson.  The bucket is immediately placed in the fish lab and this is when the fish sorting team starts our work.

Cobb Trawl net
Dropping the catch from the Cobb Trawl net into the bucket.
fish on a sorting tray
A volume of fish just placed on a sorting tray. This catch has a lot of anchovies, krill, and California smoothtongues.
Separating the krill
Separating the krill from the myctophids, Northern anchovies, and California smoothtongues.
Sorting fish group photo
Team Red Hats sorting fish. NOAA’s Keith Hanson in the rear left side.


SORTING AND COUNTING METHOD

We start by carefully picking through a 2000 mL or 5000 mL volume of the harvest, depending on Keith Sakuma’s initial assessment of the species density and volume in the bucket.  The first volume of catch to be sorted is evenly dispersed onto four white sorting trays arrayed on the main lab bench. Once you have a pile of the catch on your tray, you start to separate them into piles of different types of organisms, such as Northern anchovies, ctenophores, krill, salps, pyrosomes, Californian smoothtongues, squid, rockfish, myctophids, and young of year (YOY) fish.  I prefer to use my hands for sorting while others use forceps. Once sorted, we count the number of individuals for each species. If we have difficulty identifying an animal that we have not yet seen, we ask Keith Sakuma or a more experienced team member to help with identification. YOY fish, some in larval form, are particularly difficult for me.

Once sorted and counted, we verbally call out the common name and number of organisms to Keith Sakuma who manually records the data in a 3-ring binder for the lab hard-copy.   For smaller organisms, such as krill or salps, or in hauls with a high number of any particular species, it would be quite tedious to pick out and count each individual in the total haul.  This is why we start with a small subsample volume or 0.5, 2 or 5L, count the individuals in that small volume, establish the ratio for the number of individuals in that volume, and then extrapolate and calculate by the total volume of the haul.  For example, if we counted 97 pyrosomes in the initial 5L sort, and we collected a total of 1000L, then we can say that there are 19,400 pyrosomes in the haul.

Chief Scientist Keith Sakuma
Chief Scientist Keith Sakuma recording the data from a haul during sorting.

Once 20 individuals of each species have been called out, we no longer have to count that species since the ratio for this catch has already been established and to expedite sorting the rest of the volume.  Following sorting, the length of the twenty representatives of each species is measured using electronic calipers and the values populate on an Excel spreadsheet. After measuring, specimens requested by various research institutes including Scripps Institution of Oceanography, Moss Landing, and Monterey Bay Aquarium Research Institute (MBARI) are collected, labelled and frozen.

Flora Cordoleani
Flora Cordoleani keeping track of which specimens are to be preserved for various research groups.
Keith Sakuma bagging specimens to send to collaborators.

Creature(s) feature: Salps and Pyrosomes. 

Salps What are these strange gelatinous organisms in our catch that look like little puddles of clear jelly with a red, green, yellow, and brown digestive organ in the center?  They are goopy, small and slippery making them difficult to pick up by hand. They float on the sea surface and are ubiquitous in our hauls BUT NOBODY KNOWS ABOUT THEM.

These creatures are called salps and belong to the subphylum Tunicata. Tunicates have a notochord in their early stage of life which makes them members of the phylum Chordata, to which humans also belong. Having a transparent body is a way escape being preyed upon.

A group of salps. This species is dime to quarter sized and this number of salps occupies a volume of ~10-15 ml once placed in a beaker.
Salp digestive organs.

Salps are planktonic tunicates  That can be found as individual salps or in long chains called blastozooids.   The salps shown in the photo below were individuals and were notable in most of our hauls. Individual salps in this pile are dime to quarter sized and occupy a volume of ~10-15 ml. We measured the volume of salps in every haul.

While on the topic of salps, I will tell you about a cool 1 inch long salp parasite I found on my sorting tray (see image below). Keith Sakuma explained that it was a deep sea amphipod called Phronima which is a parasitoid that takes up residence inside of a salp’s body, eats the salp’s organs, and then lays its eggs inside of the salp. The King-of-the-salmon, Trachipterus altivelis, (which we are also catching) uses its protrusible jaw to get inside of the salp just to eat this amphipod!

Phronima amphipod
Phronima amphipod – lives and reproduced in salp after eating the salp’s organs. King-of-the-salmon fish use their protrusible jaws to eat the amphipod.
King-of-the-salmon
King-of-the-salmon, Trachipterus altivelis
King-of-the-salmon jaw protruded
King-of-the-salmon, Trachipterus altivelis, who preys upon phronima living inside of salp, with jaw protruded.
A large haul full of salps.

Another type of salp we keep catching is Thetys vagina, a large solitary species of nektonic salp that feeds on plankton, such as diatoms, and is an important carbon sink in the ocean. Thetys has an external surface, or test, that is covered with bumps and ridges, as seen in the photo below.

Thetys vagina, the twin-sailed salp.
Thetys vagina, the twin-sailed salp.
internal filtering organ
The internal filtering organ of Thetys vagina.
Kristin Saksa examining a larger Thetys
Kristin Saksa examining a larger Thetys vagina, or the twin-sailed salp. The dark colored tentacles are downward facing. This is the siphon where water enters the sac-filled body.

Pyrosomes Pyrosoma atlanticum are another type of planktonic tunicate which are very numerous in most of our hauls. Pyrosomes look like bumpy pink hollow tubes with openings on both ends. They are rigid in structure and easy to pick up by hand, whereas salps are goopy and difficult to pick up by hand.  We have collected some pyrosomes that are 13 inches long, while most are in the 4-6 inch range. The small pyrosomes look like clear Tic Tacs, but they do not taste as such.

Pyrosoma atlanticum
Pyrosoma atlanticum, with an ~6 inch specimen on the left and small pyrosomes on the right.

How can pyrosomes be so ubiquitous just 20 miles or so off of the Central California Coast, but I have never seen one that has floated up on the beach or while swimming?

Pyrosoma atlanticum are also planktonic tunicates, but are colonial organisms made up of many zooids held together by a gelatinous structure called the tunic. One end of the tube is wide open and filters the water for zooplankton and phytoplankton, while the other end is tighter and resembles a diaphragm or sphincter. The pyrosomes we harvested appeared in diverse array of pinks and purples.  Pyrosomes are believed to harbor intracellular bioluminescent bacteria. Pyrosomes are drifting organisms that swim by beating cilia lining the branchial basket to propel the animals through the water and create a current for filter feeding. 

Pyrosome rainbow
Pyrosoma atlanticum assorted by color.
Kristin Saksa
Moss Landing Graduate Student Kristin Saksa excited about the large haul of Pyrosoma atlanticum.
high-five
Pyrosoma atlanticum high-five.

Dawn White: Pinging for Populations, June 29, 2017

 

NOAA Teacher at Sea

 Dawn White

Aboard NOAA Ship the Reuben Lasker

June 19 – July 1, 2017

 

Mission: West Coast Sardine Survey

Geographic Area of Cruise: Pacific Ocean; U.S. West Coast

Date: June 29, 2017

 

Weather Data from the Bridge

Date: June 29, 2017                                                         Wind Speed: 7.7 kts

Time: 6:15 p.m.                                                                 Latitude: 4805.5N

Temperature: 12.7oC                                                      Longitude: 12520.07W

 

Science and Technology Log

The technology present on this ship is amazing and at the same time quite overwhelming.  These systems allow for data to be collected on a wide range of variables both continuously and simultaneously.  Below are a couple of photos of the acoustics room where multiple sensors are monitoring the feedback from sonar systems placed below the ship’s hull.  One of the acoustic probes sends out sound waves in a cone-like formation directly below the ship.  Another unit emits sound waves in a horizontal pattern.  The ship was designed to run as quietly as possible so as to not disturb the marine life present in the waters as the ship passes by and also to reduce the interference of the ship’s sounds with the acoustics feedback.

 

 

Acoustics technician Dan Palance managing the multiple computers that are constantly collecting data.

Multiple programs help to eliminate the “noise” received by the probes until all that remains are images that represent schools of fish and their location relative to the ocean floor.

 

The images above were taken from a poster on board the Reuben Lasker. They illustrate the range of the water column surveyed by the various acoustic systems.

 

The “soundings” are received by the ship, processed and “cleaned up” using a series of program algorithms. The image below shows the feedback received from one of the systems.

Displays of feedback from an acoustics system

Once the background “noise” has been eliminated, the resulting image will show locations of fish, school size, and the depth (y axis) at which they can be found.

Graph of acoustic feedback, with background “noise” eliminated, depicting depth and size of fish schools

 

Extension question for my students reading this:  Approximately how deep are the schools of fish being picked up by the sonar at this location?

Acoustics aren’t the only tools used to try pinpoint the locations of the fish schools.  As I wrote about on an earlier blog, the CUFES egg sampler is used to monitor the presence of fish eggs in the waters that the ship passes over.  Water samples are analyzed every half hour.  If egg samples appear in an area where there is also a strong acoustics signal, then that may be a location the ship will return to for the night’s trawl.  The main focus of this trip is to monitor the anchovy and sardine populations, so extra attention is paid to the locations where those eggs appear in the samples.

Personal Log:

Each time we drop the net for an evening trawl it is always retrieved with a bit of suspense:  What’s going to be in the net this time?  How big is the haul?  Will we capture any of the key species or haul in something completely different?

I can honestly say that while on board there were no two hauls exactly the same.  We continued to capture large quantities of pyrosomes – unbelievable amounts.  Check out the net-tearing load we encountered one night.  We literally had to weigh them by the basketful!

Here I am getting ready to help unload this large catch.

TAS Dawn White prepares to help unload large catch

 

Net-tearing load of pyrosomes!

Above is the codend of the net filled with pyrosomes and fish.  A 5-basket sample was pulled aside for analysis.  The remainder was simply classified and massed.

While I was certainly don’t need to see another pyrosome any time soon, there were plenty of other times when some very unique species made an appearance!

Pacific Jack Mackerel

Solitary Common Salp

TAS Dawn White holds a Blue Shark

Dogfish Shark

Did you know?

The dogfish shark (pictured above) was one of about 50 or so that were caught in the same haul.  We had trawled through a school that was feeding on the small fish found at the ocean surface during the evening hours.  This is the same species of shark that is commonly provided to students for dissection.  Use the search terms “dogfish shark dissection” and see what you find!

Jennifer Fry: March 15, 2011, Oscar Elton Sette

NOAA Teacher at Sea
Jennifer Fry

Onboard NOAA Ship, Oscar Elton Sette

March 12 – March 26, 2012

Mission: Fisheries Study
Geographical area of cruise: American Samoa
Date: March 15, 2012

Pago Pago, American Samoa

Science and Technology Log:

Nighttime Cobb Trawling : Day 4

We began the trawling around 8:30 p.m.  The data we collect tonight will replace the previous trawl on day 2 which was flawed in the method by which the experiment was collected. The Day 2 experiment was when the winch became stuck and the trawl net was left in the water well over 2 ½ hours, long past the 1 hour protocol.

Here’s is what the science team found.

Tonight the trawl nets went into the ocean and were timed as all the other times.

During the sorting we found some very interesting species of fish which included:

  • Pyrosomes: chordate/Tunicate
  • Two Juvenile cow fish (we placed them into a small saltwater tank to observe interesting species caught in the net.)

This is a great place to make further observations of these unique animals.

The data collected included:

Name of fish: Numbers Count Volume (milliliters) Mass (grams)
Myctophids 120 700 650
Non-Myctophids 148 84 115
Crustaceans 77 28 40
Cephalopods: 16 64 50
Gelatinous zooplankton 71 440 400
Misc. zooplankton n/a 840 900

The Cobb trawl net was washed, rinsed and the fish  strained through the net. They were then brought inside the web lab for further sorting.

The white-tailed tropic bird is a regular visitor to the South Pacific islands.

We were close to finishing the sorting, counting, and weighing when suddenly we heard something at the back door of the lab.  Fale, the scientist from American Samoa went to the door and proceeded to turn the latch, and slowly opened the door.  There huddled next to the wall, near some containers was a beautiful black and white Tropic bird, a common bird of this area.  Its distinctive feature was the single white tail feather that jutted out about 1 foot in length.  He looked just as surprised to see us and we were of him.  He did not make a move at all for about 10-15 minutes .  We took pictures and videos to mark the occasion, yet he still didn’t budge or act alarmed.

With a bit more time passing, he began to walk, or more like waddle like a duck. His ebony webbed feet made it difficult to maneuver over the open slats in the deck.  He attempted flight but appeared to get confused with the overhanging roof.

I quickly found a small towel and placing it over his head, gently carried him to a safe spot on the aft deck where he would have no trouble flying away.

The time was about 2:00 a.m. when we were distracted by the ship’s fire alarm, and  we quickly reported to our muster stations.  Luckily, there was no fire and  we returned resuming our trawl data collection.  Upon reaching the wet lab, we noticed at the stern of the ship, our newly found feathered friend had flown off into the dark night.

It was a great way to end our night with  research and early hour bird watching.  How lucky we all are to be in the South Pacific.

Animals Seen:

Ppyrosome

Pictured here is a Pyrosome which many came up in our Cobb net.

Cow fish

Our trawl net caught three juvunile cow fish specimans which were quickly placed in our observation tank for further study.

Tropical bird

The Tropic bird, with its distinctive long tail feather, is common in the South Pacific.