Karah Nazor: The Glowing Dolphins of the Channel Islands and Interview with UCSC Graduate Student Ilysa “Ily” Iglesias, May 31, 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 31, 2019

Game Plan and Trawling Line: Channel Islands San Nicolas Line

I am up on the flying bridge and I just saw two humpback whales spouting, an albatross soaring and a large Mola Mola on the sea surface.  In this blog I will write about an amazing once in a lifetime experience that from last night- May 31, 2019. The first haul was called off due to an abundance of Pacific White-Sided Dolphins, Lagenorhynchus obliquidens, (as reported by the inside marine mammal watch prior to net deployment), so we motored on ahead to the second station, but dolphins chased the ship all the way there, too.  One strategy to encourage marine mammals to leave is for the ship to stop moving with the hope that the dolphins become disinterested and vacate the area. This pod was intent on having a party at the ship so Keith Sakuma encouraged everyone to just go outside to observe and enjoy the dolphins! 

Fishing on this survey takes place at nighttime (so the fish do not see the net) and Scripps graduate student Kaila Pearson and I stepped outside on the side deck into the darkest of dark nights. Kaila and I carefully placed one foot in front of the other because we couldn’t see our feet and where to step next. I was afraid I would trip. When I asked Keith Hanson if we should use a flashlight to safely make our way up to the top deck, he suggested that we stay in place for a few minutes to allow our eyes to adjust. Within 5 minutes or so objects around us started to present themselves to us within the black void.  We could eventually see our feet, each others faces, the dolphins, and even the finer features of the sea surface.

Within a few minutes Ily Iglesias reported seeing bioluminescence, a type of chemiluminescence that occurs in living things, such as the familiar green glow of lightening bugs in the Summer in the South.   This glow results from oxidation of the protein luciferin (present in photophore cells/organs) by the enzyme luciferase.  It its excited state, lucifern emits light.  This reaction is known to occur in some marine bacteria, dinoflagellates (single celled photosynthetic organisms), squid, deep sea fish, pyrosomes and jellyfish, and I am fortunate to have observed many of these creatures already on this research cruise (see photos below).  Some animals have photophore organs and generate their own luciferin, while others are hosts to bioluminescent bacteria.

deepsea longfin dragonfish
The large photo organ is a large green circle under the eye of the deepsea longfin dragonfish, Tactostoma macropus.
California lanternfish
California lanternfish, Symbolophorus californiensis, with photophores under the lateral line and the ventral surface.
California lanternfish photophores
California lanternfish photophores
Blue lanternfish
Blue lanternfish, Tarletonbeania crenularis, collected from a bongo net at 265 meters. Photophores line the ventral surface of the body.
Cranchia scabra
Cranchia scabra “baseball squid” with large photophores lining the eyes.
Chiroteuthis veranii squid
Chiroteuthis veranii squid

When dinoflagellates floating on the sea surface are agitated, they glow.  At first when I was trying really hard to see this, I noticed a couple of tiny flashes of green light, sort of like lightening bugs, but it wasn’t anything super obvious. In time, I noticed clouds of faint light, sort of like a glowing mist floating the water’s surface, that moved up and down with the swell.  I hypothesized that dinoflagellates on the sea surface were being agitated by the passage of waves through them and Ily suggested that it was caused by schools of anchovies.

Since the dolphins were intent on staying, we decided to head to the next station.  I knew that as the ship began to move that the bow would be breaking through surface water that had previously been undisturbed, and I predicted the bioluminescence would be much more intense.

As we took off, the dolphins began to bow surf and, as I predicted, the dinoflagellates were activated and this time their glow was a bright white.  As the dolphins surfaced to breath, their skin became coated with the glowing algal cells, creating an effect as if they were swimming in an X-ray machine.  The dolphins were literally glowing white swimming in a black sea! We were so entranced and excited by the beauty, we screamed in delight. I am sure the dolphins heard us cheering for them. They too, seemed excited and could see each other glowing as well.

Next we saw the faint cloud of dinoflagellates caused by Northern anchovies (Ily was right) up ahead of us. As the ship encountered the school of small (~ 3-6 inch) fish, they also started to glow really bright and it was easy to see all of the individual fish in the school. The dolphins could also see the glowing fish and split off in different directions to hunt them.  There were hundreds of fish that dispersed as they were being chased creating a pattern of short white glowing lines somewhat like the yellow lane markers on the highway.

The display was unlike anything I have ever witnessed. It was like the Aurora Borealis of the sea.  Despite our best efforts, our cell phone cameras were unable to pick up the bioluminescent signal, however, we do not need photos because the patterns of light will be forever embedded in our minds. The dolphins eventually tired from the surf and chase and departed. Ily said the experience was “an explosion of light that overwhelmed the senses” while Flora said it was “better than fireworks.”

With no marine mammal sightings at the third station, we completed a five minute haul in the deep channel and collected a huge white bin of anchovies (see photo of Keith Hanson with this catch below). In this catch we found a few Mexican lampfish, 3 king of the salmon, a lot of of large smooth tongues, a lot of salps, a few pyrosomes and one purple striped jellyfish.  The purple-striped jelly (Chrysaora colorata) is is primarily preyed upon by Leatherback turtles. Haul 2 was conducted over shallower water near San Nicolas Island and we only found salps and four small rockfish in the catch.  After these two hauls, we called it a night and wrapped up at 4:15 a.m.

Scientist Spotlight: Ilysa Iglesias, NMFS SWFSC FED/ University of California Santa Cruz (UCSC)

Ilysa “Ily” is a doctoral student who works in John Field’s Lab at UCSC.  She is studying the fish we are collecting on this cruise as part of her research. She is very knowledgeable about all of the survey research objectives. She is also one of the most positive and gregarious people I have every met. Ily grew up in Santa Cruz, CA, and enjoys surfing, hiking, gardening and raising chickens.   Ily is a fan of early marine explorer Jacques Cousteau, who often wore a red beanie/toboggan and a blue shirt. Ily came prepared and brought six red hats (that she knit herself) for each of the members of the sorting team. Ily’s favorite fish is the hatchetfish. She was thrilled when we found on in the catch!

Ilysa with hatchetfish
Ilysa Iglesias with deepsea marine hatchetfish
deepsea marine hatchetfish
A deepsea marine hatchetfish caught in the bongo which was deployed to depth of 265 meters.

Ily obtained a Bachelor’s degree from UC Berkeley in integrated biology and a Masters Degree from the University of Hawaii in Zoology with a specialization in marine biology.  Her thesis was on the function of intertidal pools as a nursery habitat for near-shore reef fish. She compared otoliths (fish bone ears) of fish reared inside and outside of tide pools and compared their growth rates.  Otoliths can be used to the age of the fish much like counting rings on a tree and stable isotope analysis reveals information about where the fish were reared.

Ily, Flora and Kristin have all used otoliths in their research and taught me how to locate and collect the sagittal otolith from anchovies and myctophids. It is a tiny ear bone (one of three) that is positioned near the hindbrain of fish.  See photos below of the otoliths we collected. This is a technique that I will definitely take back to my classroom and teach my McCallie students.

Otoliths we collected and observed under the dissecting microscope.
Photomicrograph of otoliths
Photomicrograph of otoliths we collected from blue lanternfish (top) and Northern Anchovy (bottom) and observed under the dissecting microscope.

After obtaining her masters degree, Ily was Conservation Fellow for the Nature Conservancy in HI and worked in octopus fisheries before returning home to join NOAA’s salmon team and then the rockfish team as a Research Associate.  Ily has just completed the first year of her doctoral work in the Field Lab and expects to complete the program within 5 years.

On this cruise, Ily is collecting small fish called Myctophids for her research. These are small bioluminescent fish that live at depths of 300 and 1,500 m in the bathypelagic zone. In this survey, we encounter these deep sea dwellers during their nightly vertical migration up to the edge of the photic zone at depths we are targeting.  They are likely chasing their prey (krill) on this upward journey. It is amazing to me they are able to withstand the pressure change. Mcytophids are also known as lanternfishes and have bioluminescent photophores dispersed on their bodies. The fish sorting team analyzes the position of these organs to help distinguish between the different species. There are 243 known species of myctophids, making these little fishes one of the most diverse vertebrates on Earth.  They are so abundant in the sea that they make up 65% of the ocean’s biomass, but most people have never heard of them!

In 2014- 2015 there was an anonymously high sea surface temperatures off of the Pacific Coast known as The Blob.  Marine scientists are still elucidating the effect of the hot water had on fish populations and ecosystems. Ily explains that “atmospheric forcing caused changes in oxygen and temperature resulting in variability in the California current.”  The water was less nutrient dense and caused a reduction in phytoplankton. This disruption of primary production propagated up the trophic cascade resulting in die offs of zooplankton, fish, marine mammals and birds.  

Ily is using the catch records and acoustics data from the rockfish survey to study changes in distribution and abundance of myctophids from before, during and after The Blob (2013-2019).  She aims to understand if and how their trophic position of myctophids was affected by the unusually high sea surface temperatures.   Using elemental analysis isotope ratio mass spectrometry to analyze the Carbon and Nitrogen atoms incorporated into fish muscle, Ily can determine what the myctophids were eating each year.

Lisbeth Uribe, August 5, 2008

NOAA Teacher at Sea
Lisbeth Uribe
Onboard NOAA Ship Delaware II
July 28 – August 8, 2008

Mission: Surfclam and quahog survey
Geographical Area: Southern New England and Georges Bank
Date: August 5, 2008

Chief Scientist Vic Nordahl, Chief Boatswain Jon Forgione and Chief Engineer Patrick Murphy discussing the best way to reattach the pump power cable to the dredge.
Chief Scientist Vic Nordahl, Chief Boatswain Jon Forgione and Chief Engineer Patrick Murphy discussing the best way to reattach the pump power cable to the dredge.

Ship Log 

In the last 48 hours the engineers, crew and scientists have had to re-attach the power cable to the dredge (see photograph), fix the cracked face plate of the pump, replace the blade and blade assembly, change the pipe nozzles that direct the flow of water into the cage, and work on the dredge survey sensor package (SSP). Dredging is hard on the equipment, so some mechanical problems are to be expected. The main concern is for lost time and running out of critical spare parts.  So far we have had great success with making the repairs quickly and safely.

Science and Technology Log 

Collecting Tow Event and Sensor Information for the Clam Survey 
Over the weekend I was moved up to the bridge during the towing of the dredge. I was responsible for logging the events of each tow and recording information about the ship and weather in a computerized system called SCS (Scientific Computer System). I listened carefully to the radio as the lab, bridge (captain) and crane operator worked together to maneuver the dredge off the deck and into the water, turn on the pumps, tow the dredge on the seafloor bottom, haul the dredge up, turn off the pump and bring the clam-filled dredge back on deck. It is important that each step of the tow is carefully timed and recorded in order to check that the tows are as identical as possible.  The recording of the events is then matched to the sensor data that is collected during dredge deployment. As soon as the dredge is on deck I come downstairs to help clean out the cage and sort and shuck the clams.   

Lisbeth is working on the bridge logging the events of each tow into the computer system.
Lisbeth is working on the bridge logging the events of each tow into the computer system.

My next job assignment was to initialize and attach to both the inside and outside of the dredge the two mini-logger sensors before each tow. Once the dredge was back on deck I removed both mini-loggers and downloaded the sensor data into the computers. Both sensors collect pressure and temperature readings every 10 seconds during each tow. Other sensors are held in the Survey Sensor Package (SSP), a unit that communicates with onboard computers wirelessly.  Housed on the dredge, the SSP collects information about the dredge tilt, roll, both manifold and ambient pressure & temperature and power voltage every second. The manifold holds the six-inch pipe nozzles that direct the jets of water into the dredge.  Ideally the same pump pressure is provided at all depths of dredge operation. In addition to the clam survey, NOAA scientists are collecting other specimens and data during this cruise.

Two small black tubes (~3 inches long), called miniloggers, are attached to the dredge. The miniloggers measure the manifold (inside) and ambient (outside) pressure and temperature during the tow.
Two small black tubes (~3 inches long), called miniloggers, are attached to the dredge. The miniloggers measure the manifold (inside) and ambient (outside) pressure and temperature during the tow.

NOAA Plankton Diversity Study 
FDA and University of Maryland Student Intern Ben Broder-Oldasch is collecting plankton from daily tows.  The plankton tows take place at noon, when single-celled plants called phytoplankton are higher in the water column. Plankton rise and fall according to the light. Plankton is collected in a long funnel-shaped net towed slowly by the ship for 5 minutes at a depth of 20 meters. Information is collected from a flow meter suspended within the center of the top of the net to get a sense of how much water flowed through the net during the tow. Plankton is caught in the net and then falls into the collecting jar at the bottom of the net.  In the most recent tow, the bottle was filled with a large mass of clear jellied organisms called salps. Ben then filters the sample to sort the plankton by size. The samples will be brought back to the lab for study under the microscope to get a sense of plankton species diversity on the Georges Bank.

An easy way to collect plankton at home or school is to make a net out of one leg of a pair of nylons. Attach the larger end of the leg to a circular loop made from a metal clothes hanger.  Cut a small hole at the toe of the nylon and attach a plastic jar to the nylon by wrapping a rubber band tightly around the nylon and neck of the jar.  Drag the net through water and then view your sample under a microscope as soon as possible.

Biological Toxin Studies 

NOAA Scientist Amy Nau hauls the plankton net out of the water using the A-frame. (Upper insert: flow meter; lower insert: plankton in the collection bottle after the tow).
NOAA Scientist Amy Nau hauls the plankton net out of the water using the A-frame. (Upper insert: flow meter; lower insert: plankton in the collection bottle after the tow).

Scientists from NOAA and the Food & Drug Administration (FDA) are working together to monitor clams for biological toxins. Clams and other bi-valves such as oysters and mussels, feed on phytoplankton. Some species of phytoplankton make biological toxins that, when ingested, are stored in the clam’s neck, gills, digestive systems, muscles and gonadal tissues.  If non-aquatic animals consume the contaminated clams, the stored toxin can be very harmful, even fatal.  The toxin affects the gastrointestinal and neurological systems. The rate at which the toxins leave the clams, also known as depuration rate, varies depending on the toxin type, level of contamination, time of year, species, and age of the bivalve. Unfortunately, freezing or cooking shellfish has no effect on the toxicity of the clam. The scientists on the Delaware II are collecting and testing specimens for the two biological toxins that cause Amnesia Shellfish Poisoning (ASP) and Paralytic Shellfish Poisoning (PSP).

NOAA Amnesia Shellfish Poisoning (ASP) Study 
A group of naturally occurring diatoms, called Pseudo-nitzschia, manufacture a biological toxin called Domoic Acid (DA) that causes Amnesia Shellfish Poisoning (ASP) in humans.  Diatoms, among the most common organisms found in the ocean, are single-celled plankton that usually float and drift near the ocean surface. NOAA scientist Amy Nau collects samples of ocean water from the surface each day at noon. By taking water samples and counting the numbers of plankton cells, in particular the Pseudo-nitzschia diatoms, scientists can better determine if a “bloom” (period of rapid growth of algae) is in progress. She filters the sample to separate the cells, places the filter paper in a test tube with water, adds a fixative to the tube and sets it aside for further study in her lab in Beaufort, NC. 

Scientist Amy Nau filters seawater for ASP causing dinoflagellates.
Scientist Amy Nau filters seawater for ASP causing dinoflagellates.

FDA Paralytic Shellfish Poisoning (PSP) Study 
Scientists aboard the Delaware II are also collecting meat samples from clams for an FDA study on the toxin that causes paralytic shellfish poisoning. When clams ingest the naturally occurring dinoflagellate called Alexandrium catenella, they accumulate the toxin in their internal organs. When ingested by humans, the toxin blocks sodium channels and causes paralysis. In the lab, testing for the toxin causing PSP is a lengthy process that involves injecting a mouse with extracts from shellfish tissue.  If the mouse dies, scientists know the toxin is present. The FDA is testing the accuracy of a new quick test for the toxin called the Jellet Test Kit. After measuring and weighing a dozen clams from each station on the Georges Bank, Ben and Amy remove and freeze the meat (internal organs and flesh) from the clams to save for further testing by scientists back on land. At the same time, they also puree a portion of the sample and test it using the Jellet strips for a quicker positive or negative PSP result.

Personal Log 

Pilot whales sighted off the bow!
Pilot whales sighted off the bow!

The problems that we have experienced with regard to the dredge over the past few days are an important reminder of the need for the scientists and crew to not only be well prepared but also flexible when engaged in fieldwork. All manner of events, including poor weather and mechanical difficulties, can and do delay the gathering of data. The Chief Scientist, Vic Nordahl, is constantly checking for inconsistencies or unusual patterns, particularly from the dredge sensor readings, that might need to be addressed in order to ensure that the survey data is consistent and accurate. The time required to repair the dredge meant I was able to do a load of laundry. Dredging is very dirty work! Good thing I am using old shirts and shorts. I also caught up on a few emails using the onboard computers. Though the Internet service can be slow at times it is such a luxury to be able to stay in touch with friends and family on land. I still have two very special experiences that I wish to share before ending my log.

Late in the evening a couple of days ago, as we steamed toward our next tow station, I was invited to peer over the bow. The turbulence in the water was causing a dinoflagellate called Noctiluca to sparkle and glow with a greenish-blue light in the ocean spray.  The ability of Noctiluca and a few other species of plankton and some deep-sea fish to emit light is called bioluminesense. A few days later we had the great fortune to see five pilot whales about 100 meters away, gliding together, their black dorsal fins slicing through the water, occasional plumes of air bursting upward through their blowholes (nostrils located on the tops of their heads).

Answers to the previous log’s questions: 

1. What is the depth and name of the deepest part of the ocean? The Mariana Trench in the Pacific Ocean is 10,852 meters deep, (deeper than Mount Everest is tall – 8,850 meters).  Speaking of tall mountains, the tallest mountain in the world is not Mount Everest, but the volcano Mauna Kea (Hawaii).  It reaches 4,200 meters above sea level, but its base on the sea floor is 5,800 meters below sea level.  Its total height (above base) is therefore 10, 000 meters!

2.What is the longest-lived animal on record? In 2007, an ocean quahog was dredged off the Icelandic coast.  By drilling through and counting the growth rings on its shell, scientists determined it was between 405 and 410 years old. Unfortunately it did not survive the examination, so we do not know how much longer it would have lived if left undisturbed. This ancient clam was slightly less than 6 inches in width.