- Deep Sea Fauna
- Environmental Variability
- Consequences of DWHOS
- Student Research
- DEEPEND Publications
Recent blog posts
We are in the home stretch for this DEEPEND cruise with only one trawl left to process on our last day out here at sea. This cruise has been just as productive as every other trip we have conducted with lots of hard work, long hours, and rewarding finds! Here are some fun facts from our six cruises out here in the Gulf of Mexico:
We have found great diversity of species for the major taxa: 61 cephalopod species, 120 crustacean species and 627 fish species! These are important numbers as in the past the midwater habitat was not considered a particularly diverse region.
Here are the winners for the most abundant animal in each category:
Most abundant fish: Cyclothone sp.
Most abundant crustacean: Euphausiids
Most abundant cephalopod: Pterygioteuthis sp. (P. gemmata and P.giardi)
With regards to operations, here’s what we know:
Number of miles traveled: ~6496 miles on the R/V Point Sur out here in the big blue!
Total number of MOC trawls successfully deployed and retrieved: 122
Total number of hours the MOC was in the water: 671 hours
We have 1764 hours of acoustics data collected.
We have ~40,000 species and team photos from Dante Fenolio’s efforts.
Photo: Acoustics attached to the MOC for deployment
What have we found so far? We have found five cephalopod species and more than 20 species of fish that are new to science (descriptions are in the works) and we have approximately 180 fish species that are new records for the Gulf. We have found that each time out here, we have been surprised about how changeable the water conditions have been as we go down the water column- from moving across eddy features to observing and documenting the outward flow of the Mississippi River. We have found that hard work is exhausting but absolutely rewarding as we have so much science to share with all that we have found so far! We have been able to support more than 30 students, research technicians, and post docs through the DEEPEND program to date. This has been essential to maintaining our productivity for the last four years.
So, how has all of this amazing science been possible? We give a HUGE thank you to NOAA/NRDA and GoMRI for this opportunity to explore this unknown region of the Gulf. We now have eight years of continuous data in the same region, using the same methods which allows us to explore connections, gaps, and patterns that occur within and between these depth layers.
We also thank Captain Nic and the crew of the R/V Point Sur for their tireless work to keep our science moving each and every cruise. We wouldn’t have any science to share without you guys along the way! Thank you!
Each DEEPEND team member wants to thank their home institutions for their support for this effort over the last four years. These cruises have an extremely surprising and enlightening endeavor and we have lots more science to report on from these efforts. We expect to have research output and publications continuing for at least the next ten years. Where would we be without Matt Johnston, our data manger and land connection while on our cruises? Thanks to him for all his efforts! April Cook, our rockstar project manager has kept us all in line for the last four years and continues to do so, thank you! And, we can’t go without thanking our amazing director, Tracey Sutton- his work ethic combined with humor has allowed us all to grow as a team over the years, thanks, Tracey!!
Photos: April and Tracey sorting a sample; Tracey with a Mahi
Keep checking in on us for more news, publications, and highlights from the DEEPEND science team as we continue to “fish for answers”…. Until we sail again!
My name is Nina Pruzinsky. I am a graduate research assistant in Dr. Tracey Sutton’s Oceanic Ecology Lab at Nova Southeastern University. I defended my master’s thesis on the “Identification and spatiotemporal dynamics of tuna (Family: Scombridae; Tribe: Thunnini) early life stages in the oceanic Gulf of Mexico” in May and will continue working in Dr. Sutton’s lab post-graduation. In my thesis, I determined characteristics that differentiate juvenile tuna species, which have been previously poorly described, and then mapped the distributions of the most abundant species (little tunny, blackfin tuna, frigate tuna, and skipjack tuna) collected in the Gulf of Mexico from 2010-2011 and 2015-2017.
Photo: Nina with a juvenile little tunny
With that being said, this is my first DEEPEND cruise! I am ecstatic to be a part of the team that is out surveying the Gulf’s deep pelagic ecosystem. I have worked with these specimens in the lab for the past two and a half years, and it is incredible to see the specimens when they first come up in the nets! The different coloration patterns and photophores of these deep-sea fish are amazing to see! On this DEEPEND cruise, I am working as the database manager and work alongside Natalie Slayden. Our job is to back process the fish specimens identified by taxonomists Drs. Tracey Sutton and Jon Moore. Check out Natalie’s blog below to learn more about our jobs at sea.
In regards to my research, I am continuing to sample the larval and juvenile tuna in the Gulf of Mexico. Scombrid counts on this cruise exceed all other DEEPEND cruises thus far! On this cruise, we have collected various scombrid species and life stages. The majority of our catch has consisted of larval and juvenile little tunny. Due to the collaboration with C-Image III, we have also fished/caught adult tunas as well. As Heather mentioned, we are collected tissue samples of these adults for C-Image III and for stable isotope analyses conducted by Travis Richards.
Photo: Mixed larval tuna species (mostly little tunny)
We have collected larval and juvenile frigate and bullet tuna. At the juvenile stage, these two species cannot be differentiated; thus, we are running genetic analyses to determine which species this specimen is (see picture below). Additionally, we found a skipjack tuna in the stomach of one of the adult little tunny that Max Weber caught on the cruise! The MOCNESS also collected a larval skipjack as well. We also caught an adult bonito, and Gray Lawson, our MOCNESS operator, caught an adult yellowfin tuna. It is exciting to see the diversity of tuna species collected this trip!
Photos: Max and Nina with a little tunny; Bottom photo: Gray with a yellowfin tuna
As I spent the majority of my thesis surveying larval and juvenile tunas, this cruise was the first time I saw adult tunas. We had several schools circling the boat, which was very exciting!! Hoping for more tuna sightings and catches as the cruise continues! J
The DEEPEND program has provided the opportunities for collaboration in so many areas over the last four years! In the education and outreach arena, we have been working with the Oregon Coast Aquarium (http://aquarium.org/education/oceanscape-network/) who highlights DEEPEND work and created our DEEPEND Vertical Distribution poster. This collaboration was made possible by one of our EO team members, Ruth Musgrave, who oversees our K-6 education components. We have worked with middle and high school teachers from Florida to Texas through our Teacher-At-Sea program and have remained in contact with many of them years after their at-sea experiences. We have also collaborated through community efforts such as the St. Petersburg Science Festival where both DEEEPEND and C-Image consortia shared space to enlighten children and adults about our offshore projects through interactive games and question and answer sessions.
Photos: DEEPEND Vertical Migration Poster and 2) C-IMAGE II and DEEPEND teams at the St. Petersburg Science Festival
Throughout the four years, our research efforts have also expanded outside of our consortium and other GoMRI groups. For example, in my case, I have been collaborating with other cephalopod researchers around the world about things we are discovering here in the GoM. From new species descriptions to future publications, I have truly benefitted from the DEEPEND work we have conducted to date!
One exciting new collaboration is the alignment of DEEPEND and C-Image III (http://www.marine.usf.edu/c-image/) consortia to tackle an existing gap in the offshore datasets we’ve been collecting. If you look to the DEEPEND shiptracker on our website, you will see the stations we are visiting for our MOC10 sampling work. What is great is that on August 10th, the C-IMAGE III team will head out to the same stations we’ve visited to conduct their longlining project. A total of 36 pelagic longline sets will be made with two gear sets per station (one during daylight and a second at night). This add-on longline survey will evaluate the abundance, food habits, and population demography of the predators, to take tissue samples for toxicology studies, and to evaluate the stomach fullness, species composition and to obtain genetic samples of prey items.
Photo: C_IMAGE III Director, Steve Murwawski catching a Red Snapper on a previous C-IMAGE cruise
Basically, C-IMAGE III will be collecting stomachs for a subsest of our consortia teams to examine to attempt to fill the gap of knowledge between our deep-sea organisms and their large pelagic fishes. What is the gap? Food web connections are difficult as there are many, many variables involved with who eats whom, when does everybody eat, at what depth are they eating, etc. If we can connect the DEEPEND organisms with these more shallow top predators, we will gain a better sense of the energy transfer that occurs between these two groups. We will be working with this new project when everyone is back on land and in the labs!
Assessing marine ecosystems health requires multiple tools to study in an integrative way environmental pollution and impacts across different biological levels. One of the main challenges is to link physical, chemical and biological components in large-scale ecosystems when little information is available. For example, the Deepwater Horizon oil spill in 2010, contaminated the water column in the Gulf of Mexico from the epipelagic (0-200 m) to the mesopelagic (200 -1000) and bathypelagic (>1000 m) habitats; but assessment of the impact to the deep-pelagic GoM was hampered due to a lack of comprehensive data regarding diversity, abundance, distribution, and pollutants baseline-content of pelagic fauna. Several programs since the spill (e.g. DEEPEND Consortium) have improved our knowledge and understanding of the deep-pelagic ecosystem, the largest habitat in the Gulf of Mexico, and on Earth. However, information regarding the source, composition and inputs of chemical contaminants to deep pelagic fauna is still absent. Chemical contaminants can alter biological diversity and ecosystem functioning, therefore are key for linking long-term population dynamics and environmental stressors.
As part of the DEEPEND Consortium, my role is to establish a time series of chemical composition in deep-pelagic fauna (fishes, shrimps, cephalopods) collected after the Deepwater Horizon spill. For this study, the analysis of polycyclic aromatic hydrocarbons (PAHs) was chosen because: 1) these compounds are common in crude oil; 2) are persistent in the environment; 3) their composition can be used to broadly detect the source of contamination; and 4) can be toxic to fauna. PAHs are a large group of organic compounds organized in multiple aromatic rings typically found as complex mixtures. They are present in petroleum, coal, wood, and their combustion products. When present in high amounts, for example after an oil spill in the ocean, PAHs can cause lethal and sub-lethal effects on fauna like juvenile and adult fishes, potentially increasing mortality, skeletal malformations, genetic damage, immunotoxicity, etc.
Recently, with the collaboration of different programs, we were able to establish a decadal assessment of PAHs in mesopelagic fish tissues as indicators of environmental contamination in the deep-pelagic ecosystem. The results generated from this study indicate deep-pelagic fishes were exposed to elevated concentrations of PAHs after the Deepwater Horizon spill (2010-2011). In 2015-2016, PAH concentrations were close to the levels measured in 2007; but only for muscle tissues, because elevated concentrations were found in ovaries containing eggs. The high concentrations of PAHs found in 2010-2011 (muscle tissue), and 2015-2016 (eggs) are within the range of PAH concentrations found to cause lethal and sublethal effects on fishes. These results suggest a long-term sink for oil in deep pelagic organisms, potentially greater than shallower counterparts. Our findings demonstrate the importance of monitoring the persistence of organic contaminants in deep pelagic organisms. However, our study also indicates the need for more extensive ecosystem-based efforts of the deep-pelagic ocean (> 10 years) to better understand the long-term impacts across multiple levels of biological organization.
Here are some of the animals I am examining for PAH contamination:
1) Cyclothone obscura; 2) Onychoteuthis banksii,; 3) Histioteuthis corona
For DEEPEND, I am one of the taxonomists that identify the cephalopods (squid and octopus) that are collected from the MOCNESS nets. I am also collecting two other mollusc groups, pteropods (Sea Butterflies) and heteropods (Sea Elephants). Once animals are identified, tissue could go to one or more of the following places for further DEEPEND study: Stable isotope analysis (examples food web interactions among fauna), PAH (studying possible contaminants), or genetic barcoding for species identification verification and genetic diversity analysis.
Photo 1: A Sea Elephant, Carinaria sp.
Photo 2: A sample of Sea Butterflies (pteropods)
One of the advantages of using the MOCNESS is that we can collect organisms at discreet depths to analyze patterns on a fine scale. All focus animals: fishes, crustaceans, gelatinous organisms, and cephalopods are examined to piece together a more complete picture of the midwater column dynamics as they all contribute to the carbon moving from the surface waters to the deep-sea floor.
Team Mollusca are looking at vertical migration patterns for our three groups. Past studies on cephalopod vertical migration involve very few individuals per species so it is important to make the most of the large collection we have to further analyze these patterns. Our findings suggest that there is no one set vertical migration pattern by group but the patterns differ by species. For example, deep-sea pelagic octopods and the Vampire Squid are not found above 600m in the water column while the Moon Squid and Firefly squid move from the mesopelagic (200-1000m) to the epipelagic (0-200m) nightly, presumably for feeding purposes. We are noticing similar patterns in the heteropods, some migrate upwards and some do not. Pteropod analysis is underway at this time, stay tuned!
Here are some of the molluscs that are migrators and non-migrators,
Non-migrators: Japetella diaphana and Vampyroteuthis infernalis
Migrators: Selenoteuthis scintallins and Pterygioteuthis sp.
In the DEEPEND, we apply many techniques to learn about the animals that live in the depths of the twilight zone. One of the types of equipment we use is called an echosounder. While this may sound like a strange instrument, its actually quite common and in fact is on most fishing boats, and often called the ‘fish finder’ or the ‘bottom machine’. We use a similar type of fish finder that is powerful enough to send and receive sound to the depths of the ocean and use the data we collect to study the patterns of the animals in the deep scattering layers (DSLs). In the figure, the daily migration event can be seen with many of the animals within the DSL moving from the depths into the surface at night. Interestingly, not all animals move up at night and some remain at depth and the use of the acoustic devices helps us to better understand how the DSLs change in space and time.
Photo 1: Output from the echosounder of the DSL layer moving up at dusk
Photo 2: Examples of collected animals in the MOCNESS that the echospunder attempts to pick up. Interestingly, squid and octopods don't create a strong enough signal for the echosounder to pick up.
While the echosounder provides important data about the timing, extent and intensity of the migration patterns and the DSL in general, acoustics are limited in their ability to discriminate among species. Because of this limitation, we use net to collect samples to identify the community of organisms which also permits us to describe the diversity of species that we encounter. The mesopelagic community in the Gulf of Mexico is hyperdiverse with greater than 800 species of fishes, crustaceans and other invertebrates.
Indeed, the most prominent piece of equipment that we rely on is the MOCNESS which allows us to collect specimens at through the water column.
The echosounders on the ship provide a picture of large patterns in the ocean so we can learn about the processes that are important at broad scales. However, it is often useful to be able to zoom into the layers and see the individuals that live in those deep areas and to look at them one-on-one. To achieve this, we have attached an autonomous battery-powered echosounder onto the frame of the MOCNESS and added two transducers that collect acoustic data very close to the individuals (~20-40m). By placing the echosounder closer to the animals at depth, we can actually count and measure individuals and learn about their behavior in the dark without the need for any lights. We are learning a tremendous amount from the data we have collected on these animals and are excited to see what tonight’s sampling event shows us!!
Photo: Echosounder attached to the MOCNESS and output screen of individual animals
Hi! My name is Natalie Slayden, and I am a Master’s student at Nova Southeastern University working as a Research Assistant in Dr. Tracey Sutton’s Oceanic Ecology Lab. This DEEPEND cruise is my first research cruise!
Photo: Natalie and Nina prepping the MOC
On this DEEPEND cruise, I am a part of the fish processing team. The process begins with the boat pulling the MOCNESS which is a net system consisting of six nets. One net fishes open the entire time, while the other five nets open and close at different depths allowing us to determine where we catch certain species by depth in the water column. Once the nets are pulled out of the water, the fishes are brought into the lab per net. Dr. Tracey Sutton sorts and identifies each fish to species. I then weigh, measure, and preserve the fishes based on how they will be utilized. All this information is entered into the DEEPEND database by my partner in crime, Nina Pruzinski. Several universities use these fishes for varying projects.
For my thesis project, I am looking at the otoliths (ear stones) of non-vertically migrating deep-pelagic fishes to determine their age. I will also describe the otolith patterns and correlate those patterns to the life history of the fishes. Fishes have otoliths to help them orient themselves within the water column and detect sound. The otoliths have rings that can be counted to determine age. The rings can represent days, months, years, or a single meal. The fishes I will use for my project are frozen so that I can remove and analyze the otoliths once I get back to the lab at Nova Southeastern University. Below are some pictures of the fishes that I will be using for my age and growth study!
Photo 1: Nannobranchium lineatum (Lanternfish species)
Photo 2: Chauliodus sloani (Viperfish species)
On DEEPEND cruises we spend most of our time doing science-related activities that you may have read about in previous blogs. Believe it or not, we do occasionally have down time and we have to figure out how to fill it. There is a TV in the galley that is quite popular to hang around and watch during meal times and late at night. My favorite DEEPEND pastime however, is fishing!
Photo: Max on the hunt for his first tuna
DEEPEND researchers assemble a stack of rods and reels before every cruise in the hopes we will stumble across some good fishing action. This is not guaranteed and I have been skunked on previous DEEPEND cruises. On afternoons when the net is not in the water and we are in transit to another station trolling is the go-to method of fishing. We have already landed on small tuna on this cruise while trolling.
Photo: The rod and reel assemblage area of the lab
Typically the best fishing takes place when a school of fish or some sort of floating structure (like sargassum or floating boards) is spotted. Floating structure often attract small baitfish, which in turn attract larger predators. Already this cruise we have stumbled across a school of Chicken (small) Mahi and Little Tunny. I have landed two Mahi and a Little Tunny, which was my first ever tuna species caught on a rod and reel!
Phptps: Ocean Triggerfish; Travis with a Little Tunny; Bpttom photo: Little Tunny
Photo: Laura on a DEEPEND cruise
I went on the very first DEEPEND cruise. I was in the second year of my PhD and I couldn’t believe my advisor, Dr. Heather Bracken-Grissom, was sending me to initialize collection protocols for the crustacean genetics portion of the proposed research. Because research cruises are the best (only) means of collecting our target specimens, they are very important. Moreover, every cruise is an opportunity to collect for multiple projects. When I went out that first time, I was collecting for five or six research projects…it was a lot of pressure.
Since then, the DEEPEND cruises have been a staple of my graduate school career. I’ve been on five of the six cruises. It’s difficult to describe what these cruises are like: a flurry of collection activity, a sleep-deprived science bender, a two-week oceanic boot camp. They are challenging and rewarding and they shape what sorts of questions DEEPEND can ask and address. Over the course of these cruises, I’ve collected thousands of specimens and used them to illuminate the connections between the midwater Gulf and the Atlantic.
Last month, I successfully defended my doctoral dissertation. In the days preceding the event, many DEEPEND scientists reached out to wish me luck. And along with all the concrete, quantifiable benefits of these research cruises, these communications emphasized again the myriad qualitative benefits: I’m a better scientist for having been a part of DEEPEND. On that first cruise I was a slightly under-prepared, over-eager graduate student on a ship full of experienced researchers and scientists who immediately supported and accepted me as one of them. They encouraged me and offered me a place at their table. The collaborations and relationships established on these cruises will last my entire professional career.
One month before this cruise left dock, I accepted an NIH postdoctoral fellowship at the University of Colorado. One month after we return to dock, I’ll move to Denver and take up the position in the Computational Biosciences Department. The talk I gave during the application process was comprised entirely of my work with DEEPEND – a talk refined through rehearsals with DEEPEND scientists and GOMOSES presentations.
This post is getting a little longer than I intended, so I’ll end it the way I end most cruises: with gratitude. GOMRI, DEEPEND, FIU, R/V Point Sur, Dr. Bracken-Grissom, thank you. Thank you for letting me roll with you.
Photos: Laura hard at work during DEEPEND cruises. So many crustaceans to identify and sample!
When the nets come up, it’s time to sort…. Each net is processed one net time so we don’t mix up samples between one net and another. The entire process can take anywhere from four to six hours depending on how full each cod end is. We first identify the organisms and then they go to Nina and Natalie for data entry. Animals are being used for multiple studies once we are back on our labs: DNA barcoding, genetic diversity studies, stable isotope analysis, contaminant analysis and vertical distribution studies.
Here is just a sample of some unique specimens we’ve collected so far!
Photo 1: Nina and Natalie at the data entry station
Photo 2: A sample of the over 600 euphausiids (krill) that team crusty had the pleasure of counting from one net
Photo 3: A selection of bristlemouths and a hatchetfish that was going to processing for the PAH study
Photo 4: Nina with a Fangtooth fish
Photo 5: The mollusca collected on one of the tows- 4 small pelagic snails, one small Vampire squid and a Chiroteuthis mega (deep-sea squid)
One of the new projects onboard this DEEPEND trip is the use of a drone to capture images and video from a different perspective around the Point Sur. Thomas Wheeler is a full time drone operator who contracts with different science and engineering projects that require drone work. This trip, he is assisting Ryan Killackey and Dante Fenolio who are creating a documentary titled “Life in the Dark” which focuses on various organisms that create light.
Why use a drone? Drones are quickly becoming a standard tool that we use in all areas of science. It is very important to capture the true nature of organisms in their habitat and drones can do that with little interference. In addition, using a drone broadens the scanning area for a project so more area can be covered. Lastly, drone footage captures large amounts of data that will be analyzed and used by scientists. The different perspective that drones capture provide the public spectacular images and video of events not often seen by anyone other than the scientists.
Thomas loves that this job allows him to travel to different venues and allows him to contribute to science while doing something he loves. The eternal challenge for drone work of course, is to be able to collect data in a safe manner, in this case, not allow the drone to fall to the bottom of the ocean!
Facts about Thomas’s drone, the Inspire 2 (lovingly named Zephyr):
Battery airtime: 25 minutes
Range: up to 4 miles
Here are pictures that Jon Moore took from the initial deployment and retrieval on Day 1 of this trip, Enjoy!
Photo 1: Inspire 2 ready for launch
Photo 2: Thomas piloting the first mission Photo 3: Ryan collecting the drone on the return
When the MOC10 comes up to the ship, it is time for the whole science team to leap into action. To someone not familiar to the process, it may appear to be utter chaos but each person on the team has a role and things usually run like clockwork. I say “usually” because occasionally, there is a hang-up. One hang-up has been the equipment that runs the MOC last night and today. There has to be communication between the equipment on the net frame to the computer that monitors the entire process for a successful tow. We have a wonderful MOC operator, Gray, who is the master of this equipment and has been out with us for every cruise. He has been working hard to make sure our science can happen! He has spent hours trying to troubleshoot and solve the mystery problem and so far, we have been able to deploy the nets! Thank you, Gray for all of your hard work with this!
Our MOC operator, Gray, prepping the nets
We are waiting for the second trawl of the trip to come up now and we will processing our deep-sea organisms soon! Stay tuned for some animal highlights in the following posts… We collect things from microbes to large fishes and here is a couple of photos from today!
Photo 1: Jon Moore, Tracey Sutton, Tammy Frank sorting a sample Photo 2: Travis Richards catching a Blue Runner
Hi everyone, after checking to make sure all gear, crew, and science team were onboard the R/V Point Sur, we left the dock just after midnight and we have arrived at our first station! Today, the team spent time calibrating the multibeam sonar and putting the nets onto the MOCNESS frame. You will hear more soon from the acoustics team about the sonar and I will describe the MOCNESS for you now.
Well Wishes from the Restore Sargassum Team as we moved gear into the lab
MOCNESS is an acronym for a Multiple Opening and Closing Net and Environmental Sensing System, which will deploy six nets in the water from the surface down to 1500m (~4500 ft). One net at a time opens at a specified depth (1200-1500m, 1000-1200m, 600-1000m, 200-600m, 0-200m), and net 1 which stays open as the whole system goes down to 1500m. At each depth, a net is open for 45 minutes, moving through the water and collects organisms in the cod end (container at end of each net). The whole thing is brought back onto the deck where the science team then processes the collections. We spent a couple of hours today setting up the MOCNESS nets and cod ends in a light rain and we are now ready for our first deployment which is tonight!
Assembling the nets is a team effort
This trawl we are doing tonight is the 100th trawl of the DEEPEND cruises. What an accomplishment! The nets will go down at 9pm and we will be ready to sort through the samples at 3am when processing begins.
Stay tuned for how the 100th trawl goes!
Hello, everyone! The DEEPEND team is preparing and packing up gear for our next DEEPEND cruise which will be July 18th through August 2nd. We are heading out on the R/V Point Sur from Gulfport, MS and are excited to get back out on the big blue! We will have the shiptracker and real-time surface currents maps per usual on the DEEPEND homepage and we will be blogging along the way with our progress and discoveries! Hope you can virtually join us for our adventure, stay tuned!
My name is Natalie Slayden. I am a Master’s student at Nova Southeastern University working in Dr. Tracey Sutton’s Oceanic Ecology Lab. I am studying the age and growth of deep-pelagic fishes, with case studies of meso- and bathypelagic species from the Gulf of Mexico.
All fishes have three pairs of otoliths. Otoliths are often referred to as ear stones and are located in the cranial cavity of fishes. Otoliths come in different shapes and sizes depending on the species. Therefore, otoliths can be used to identify fish species. Fishes have otoliths to help them detect sound & orient themselves in the water column. Otoliths can tell us a lot about a fish’s life history and they can also be used to determine age.
Left: Both sides of an otolith from the species Ceratoscopelus warmingii (Rivaton & Philippe, 1999). Right: Awesome picture of a Ceratoscopelus warmingii taken by Danté Fenolio.
Have you ever heard of tree rings? Trees have rings that can be counted to reveal how old they are. Otoliths have rings too! These rings can be formed daily, monthly, yearly, or during events such as feeding. Like tree rings, otolith rings can be counted to determine age. Most previous research has focused on aging coastal fishes. Now, I am working to age some mesopelagic (200 – 1000 m) and bathypelagic (deeper than 1000 m) fishes.
Above: The otolith rings of three different species (Gartner, 1991)
Fisheries have become interested in deep-sea fishes to utilize them as feed for aquaculture and as oil for omega dietary supplements. Since they are a target for fisheries, it is important that we understand how long these deep-sea fishes live. Some deep-sea fishes have rings that are formed daily. Most of these fishes with daily rings perform a daily diel vertical migration, meaning they swim from the depths up towards the surface waters at night to feed and then swim back down to the depths at dawn to avoid visual predators. Lanternfishes are one group of fishes that undergo this migration pattern and usually have an age of one year or less. We think that the daily rings are formed due to light or temperature changes that occur during their daily vertical migration. However, for fishes that do not vertically migrate and remain at depth, it is uncertain what their otolith rings represent. Are they daily or yearly? Could they represent a single meal?
So, for my thesis project I will attempt to determine what an otolith ring represents for a non-vertically migrating deep-sea fish. Second, I will be describing the otolith ring patterns and correlating those patterns to the life history of my case study fishes. Lastly, I will be providing age estimations for a number of mesopelagic and bathypelagic fishes.
Hello, everyone! My name is Kristian Ramkissoon, and I am a graduate student working in the Oceanic Ecology Lab with Dr. Tracey Sutton. As a member of the lab, I am currently studying the species composition, abundance, and vertical distribution of the deep-sea fish genus Cyclothone, whose combined numbers make it the most abundant vertebrate on the planet. This study of Cyclothone in the Gulf of Mexico is one of the first of its kind. So what are Cyclothone? The name Cyclothone refers to a specific genus of fish which includes a number of different species. They are more commonly known as bristlemouths. Below are some of the more common species that we have collected in the Gulf of Mexico.
From left to right:(Top Row) Cyclothone pseudopallida, Cyclothone braueri,
(Bottom Row) Cyclothone obscura, Cyclothone pallida
Bristlemouths are close relatives of another abundant group of deep-sea fishes, the dragonfishes, and can similarly be found within the meso- and bathypelagic zones of the ocean. Unlike their more infamous cousins, however, Cyclothone are much smaller in size and much less active (many of the Cyclothone we encounter on our cruises are hardly an inch long!)
Cyclothone pallida against a ruler and under the microscope.
Collectively, these fishes have a near-ubiquitous distribution, with various species found throughout the world’s oceans. This worldwide presence, along with their status as the most abundant known vertebrate, make understanding Cyclothone important for understanding the ecology of the deep sea. As a part of my research into the world of bristlemouths, I spent a lot of time learning the unique features that distinguish each species from one another. Some of the common traits that I used to distinguish between different Cyclothone species were skin color, tooth shape, and gill morphology. To date we have identified thousands of individual Cyclothone down to the species level, keeping close counts and measures of each!
Pigmentation found on the head of (A) Cyclothone alba, (B-C) Cyclothone atraria, (D-F) Cyclothone braueri, and (G-J) Cyclothone pseudopallida.
Body, pigmentation, and photophores of Cyclothone pseudopallida.
So far, my research has revealed quite a few interesting things about these tiny denizens of the deep! For one, we have confirmed that Cyclothone in the Gulf of Mexico, similarly to those elsewhere in the world, do not vertically migrate. Additionally, the taxonomic data collected, in combination with data from the MOCNESS (Multiple Opening Closing Net and Environmental Sensing System) seem to suggest that all six species commonly found within the first 1500 meters of the northern Gulf of Mexico occupy relatively tight and distinct depth ranges. This information tells us that Cyclothone, unlike many other deep-living predators who migrate daily, may subsist entirely on what is found at their respective depth ranges (in the deep, this can be very little!). In addition, we are attempting to assess the impact that hydrographic features such as the Loop Current and eddies formed by it may have on the distribution of Cyclothone within the Gulf of Mexico.
My name is Matt Woodstock. I am a master’s student at Nova Southeastern University studying under Dr. Tracey Sutton. My thesis project is about the trophic ecology and parasitism of mesopelagic (open ocean, 200 – 1000 m depth) fishes in the Gulf of Mexico.
Mesopelagic fishes are important consumers of small crustaceans (shrimp-like animals) and are prey of oceanic predators (e.g. tunas and billfishes). Some mesopelagic fishes undertake a diel vertical migration, meaning these fishes migrate up into the near-surface waters at night and then migrate back down into the deep, dark depths during the day. These fishes migrate so that they can avoid visual predators in the epipelagic (0-200 m) during the day but take full advantage of the abundant food supply there at night under the cover of darkness. Other mesopelagic fishes do not vertically migrate and remain deep at night. A lot of animals participate in this daily movement and it is regarded as the largest daily animal migration on Earth!
A hatchetfish (left) and a lanternfish (right). The hatchetfish does not undergo a daily vertical migration, but the lanternfish does. Images courtesy of DEEPEND/Dante Fenolio.
So what exactly do I study? My job is to dissect a wide variety of fishes and identify their gut contents and parasites. The gut contents obviously tell us what the fish has recently eaten, but the parasites I am interested in are transmitted through their diet. Certain parasites, called endoparasites, live within another animal (a host) and must go through different animals to complete their life cycle. If I find a lot of the same parasite in the same species of fish that means that fish has eaten the same prey item for the majority of its life. If I find a lot of different parasites within a species, then the diet of that fish may have shifted at some point in its life, or that fish may have a general diet where it eats many different types of prey. Results from this type of study allow us to make conclusions about the connectivity and stability of different ecosystems.
Two roundworms from fishes on DEEPEND cruises. On the left picture, notice the white, swirly looking object. This parasite is attached to the intestine, where it feeds on the digested nutrients of the host’s food.
The coolest part about my project is that many of the fishes I study have never been examined for parasites before. That means that I am the first person to see a parasite within that fish before (or I am at least the first person to write it down)! I am also studying the external parasites, called ectoparasites, of these fishes as I find them. These parasites are unique because they spend part of their lives searching for a host to latch onto, and then they attach themselves to a host for the remainder of their life (normally)! They also make for a great picture!
Two types of external parasites from fishes captured during DEEPEND cruises. These parasites will attach themselves to the host through the scales and feed on the host’s tissue or previously digested food.
My name is Rich Jones and I am a master’s student in Dr. Jon A. Moore’s lab at the Florida Atlantic University’s Honors College. Dr. Moore is an ichthyologist who has been working closely with DEEPEND since the beginning helping to identify some of the obscure and poorly studied deep-sea fishes collected from these depths. For myself, as someone who has always been excited about biodiversity, this work has been one of the greatest privileges of my life. Some of the fishes we have identified have only been seen by a handful of people before in the history of the world. The opportunity to study the habits of these rare animals with a comprehensive suite of data, let alone hold them in your hand, is a unique pleasure of working with DEEPEND. Some of the fishes we caught were less rare, but equally as mysterious in how poorly studied they are. One such obscure group entrusted to our lab were the Paralepididae, commonly known as “barracudina” due to their superficial resemblance to small barracuda (they are not related to barracuda). Samples collected by DEEPEND and NOAA cruises have presented a rare and unique opportunity to study these enigmatic little fishes, and I have spent the past few years getting to know them through my thesis research investigating their basic life history in the deep Gulf of Mexico.
Pictured here is a duck-billed barracudina (Magnisudis sp.) in its natural habitat, deep in the ocean. Duck-billed barracudina are some of the largest of the barracudinas and can grow to lengths of about one meter (3 feet). They are members of the sub-group known as “scaly” barracudina because they have more scales than the other varieties. This photograph is an extremely uncommon example of a live barracudina, taken by the NOAA Okeanos Explorer’s Remotely Operated Vehicle (or ROV) as it descended through the mid-water to survey the deep seafloor of the Gulf of Mexico.
At first, I knew nothing about barracudina. I wanted to focus on them for my master’s thesis research simply because they were so poorly studied. Once I began to get to know them, I learned that there are a lot of amazing and strange things that make these little fish special. Many of the smallest species are almost completely transparent in life, lacking all but a few scales. Some of those transparent species possess a unique type of bioluminescence along their bellies which is derived from their liver tissues. They use this bioluminescence to counter-shade their silhouettes against the dim light down-welling into the deep sea. They are all simultaneous hermaphrodites which means that they are both males and females at the same time throughout their entire lives. This type of reproductive mode is extremely rare among vertebrates but likely a useful quality in the deep-sea where encounters with potential mates are rare. They are very closely related to lancetfish (Alepisauridae) which are some of the biggest and baddest fish found in the deep pelagic. They can grow to lengths greater than 2.5 meters (8 feet)! Unlike barracudina, lancetfish are well studied because they are frequently caught as bycatch in pelagic long-line fisheries. So much so that they are often considered a pest to that fishery! The lancetfish’s smaller relatives, the barracudina, are not directly caught by the long-line fishers themselves but are frequently documented in the stomachs of those fishers’ targets, swordfish and big-eye tuna. In fact, several barracudina species were first described by science based on specimens found in the stomachs of fish bought at fish markets.
Pictured here is a juvenile javelin barracudina (Lestrolepis intermedia) collected during a DEEPEND cruise. This species is one of the “naked” barracudina, so called because they lack most scales and are highly translucent. This species has a unique bioluminescent organ that runs along its belly in a straight line and an additional photophore spot just in front of each eye. In life, these fish glow a faint yellow color. Observations from submersible expeditions in the 1950’s reported that this species exhibits a unique swimming behavior in which it orients itself vertically in the water column, rapidly switching its orientation from upwards to downwards.
Part of the reason barracudina are so poorly studied is because they are only infrequently captured in net trawls, and the specimens that are caught by nets are usually smaller representatives for their species. Given that they are infrequent and small in net sampling but frequent and large in the guts of certain top-predator fishes could mean that they are more common than we know and that they are just fast enough swimmers to avoid the nets. It could also be that barracudina are generally uncommon and just one of many important prey types to those deep-diving delicacies of the fish market. Either way, barracudina are under-appreciated, and as our impacts on the ocean increase, whether from industrial fishing, climate change, or oil spills, we will need to know more about the favorite prey of our favorite seafood to inform us about the sustainability of those treasured pelagic resources.
To that end, my work with barracudina has two main goals: (A) identify ecological patterns among the barracudina species in the Gulf of Mexico and (B) develop an easy to use key for identifying these often difficult-to-distinguish species. Regarding their ecology, I am asking some very basic questions: (1) What depths do the different species inhabit? (2) Do they vertically migrate? (3) How easily can they avoid the nets? (4) What do adult barracudina eat? And (5) Where in the water column are adults and juveniles found, respectively?
A picture of a typical sample from a MOCNESS tow that includes the common naked barracudina (Lestidiops affinis; center of photo) among other mesopelagic fishes like lanternfish and bristlemouths. While barracudina are not the most abundant, small swimmers of the deep sea, they are still relevant as they are a favorite food item for deep-diving tunas, billfishes, whales, and sharks.
What I have found is partly to be expected and partly surprising. It is not surprising, for example, that net avoidance is common among barracudina. The NOAA cruises immediately after the Deepwater Horizon oil spill utilized two different net types to sample the deep Gulf. One was a high-speed rope trawl and the other a multiple opening and closing net and environmental sensing system (or MOCNESS), which the DEEPEND cruises also employed. The mouth area of the MOCNESS is fairly small and because the net mesh size is only 3mm in diameter it cannot be towed very fast. This increases the potential for net avoidance by larger, faster swimmers. The rope trawl, on the other hand, had a much larger mouth area and could be towed much faster which made it more difficult to avoid. The rope trawl caught significantly more and significantly larger barracudina than the MOCNESS, which was to be expected.
Another unsurprising, but important, finding was that different barracudina species occupy distinctly different layers of the water column. It seems that there is a general distinction between where in the depths you find the “scaly” and “naked” barracudina types. The smaller, translucent or “naked” types are significantly more common near the surface in the lower epipelagic while the larger “scaly” types are almost exclusively found in the twilight zone of the mesopelagic. However, while the naked barracudina are much more common near the surface, they can be found throughout the water column all the way to the deepest, darkest depths. Comparing abundances caught at depth between day and night, there does appear to be a slight, but far from significant, amount of vertical migration in barracudina. I suspect that the reason there appears to be any vertical migration at all in these species may be that they are chasing their food, most of which does vertically migrate to the surface waters at night to feed.
Dietary habits also had a similar distinction between the two main types of barracudina. After dissecting the stomachs of several hundred adult specimens, I found that the naked ones seemed to be exclusively eating migrating mesopelagic fishes while the scaly types were eating mostly deep-sea shrimps. This is somewhat surprising because we would expect that small fishes, like barracudina, living in the deep sea would eat whatever they encounter and would not be very picky. It is likely that these differences in dietary habits and apparent selectivity are the result of a combination of their preferred habitats and their unique feeding behaviors, which continue to remain unclear. Rare observations from the voyages of the French submersible Bathyscaphe Trieste in the 1950’s reported that one barracudina species (Lestrolepis intermedia) indeed swims quite rapidly through the water column, “like silvery javelins”, occasionally halting to “float along like erect pieces of asparagus”, rapidly changing their orientation from looking upwards to looking downwards. It is unknown whether this is a unique hunting behavior or predator avoidance behavior or both. It is also unclear whether all barracudina species exhibit this odd behavior.
The apparent differences in distribution and diet I have found among the barracudina in the Gulf of Mexico could prove to be useful information as the different species appear to reflect distinct aspects of the deep-pelagic ecosystem where they live. The presence or absence of certain barracudina from a given area or large fish’s stomach could be used to help make inferences about the state of the greater pelagic environment. In managing an entire ecosystem, fishery managers rely on suites of different indicator species to inform them about the ecosystems that sustain our living ocean resources. For these suites of indicators to be effective, however, managers need to able to correctly identify them to their respective species. Many barracudina, especially the naked ones, are very difficult to identify to species and the keys that exist to diagnose them often require counting the number of vertebrae they have which is not an easy thing for most managers to do. As such, another goal of my research is to provide an easy-to-use dichotomous key that relies on simple measurements and illustrations of pigments to aid quick but accurate identification to species. Helping me to complete this goal is Ray Simpson, a post-doctoral researcher based at the Yale Peabody Museum, who is an excellent illustrator.
An illustration of the Spotback Barracudina (Uncisudis advena) by Ray Simpson
A picture of one of the largest (>15cm) ever recorded specimens of the Gulf of Mexico Bullis’s Barracudina (Stemonsudis bullisi). This endemic species had previously only been known and described from two juvenile specimens around 6cm long.
Like the DEEPEND consortium itself, the over-arching goal of my research is to contribute to a baseline of data that will inform future research and monitoring efforts in the deep Gulf of Mexico. In this way, even our simplest findings are superlative: three of the nineteen barracudina species captured in our samples represent first records for those species in the Gulf of Mexico, and the overall ranges of several other species have been expanded significantly thanks to our sampling efforts. We captured the largest specimens ever recorded for one species which is only known from the Gulf of Mexico. Hopefully publishing these results in an open-access outlet will provide useful information to managers when the next spill happens or when changes in deep-sea fisheries management need specific monitoring criteria. Regardless, it has been a real pleasure working with these odd little swimmers from the shadowy depths.
Check out Ray Simpson’s website here: http://www.watlfish.com/
It is an online outlet for Ray’s illustrations and an exhaustive list of Fishes of the Western North Atlantic which reads like a field guide.
My name is Ronald Sieber. I am a Master’s student at Nova Southeastern University working under Dr. Tamara Frank in the Deep Sea Biology Lab. I work with Dr. Frank as a graduate research assistant studying deep sea shrimp in the northern Gulf of Mexico. My work pertains to the general distribution and abundance of the deep sea shrimp family Benthesicymidae.
The family Benthesicymidae consists of 39 species across five genera, the most speciose of which are Gennadas (16 species) and Benthesicymus (15 species). Thus far we have collected two genera (Gennadas and Bentheogennema) consisting of six species. While the family in general can be identified by a blade-like rostrum and a bearded appearance due to the presence of setae tufts, the individual species can only be identified by the shape and structure of the genitalia. The structures are known as petasma (for males) and thylecum (for females).
Image of Bentheogennema intermedia displaying the truncate and blade-like rostrum typical of all members of the family Benthesicymidae. Adapted from Orrell and Hollowell, 2017.
Petasma (a) and thylecum (b) for Gennadas bouvieri adapted from (Kensley 1971) and Bentheogennema intermedia from (Perez Farfante and Kensley 1997). Petasmas are composed of three variously shaped lobes while thyleca are composed of various processes and flaps on the 6th, 7th, and 8th sternites that are species specific and easily identifiable.
This study is trying to establish a broader understanding of the Benthesicymidae assemblage in this region of the Gulf of Mexico. It will also look into potential abundance shifts for the individual species to see if there have been any increases or decreases in quantity over the seven years that samples have been collected. Also, this study is looking into the potential impact that the Loop Current poses to the vertical migration of the Benthesicymidae. This current, which is sporadically present in the region of study, causes an abrupt shift in water temperature that is unfavorable for these shrimp. While initial results show an impact in abundance due to Loop Current presence, further statistical analyses are required to show the potential migration shifts that the current poses.
My name is Nina Pruzinsky. I am a Master’s student at Nova Southeastern University, where I am working under Dr. Tracey Sutton. Also, I am a graduate research assistant in Dr. Sutton’s Oceanic Ecology Lab, where I am studying the identification and spatiotemporal distributions of tuna early life stages (larvae and juveniles) in the Gulf of Mexico.
Tuna are ecologically, economically and recreationally important fishes. You may know them for their large size, high speeds, and highly migratory behaviors. Fishermen enjoy catching these are fish because they average 2.5 m in size and 250 kg in weight!! They are top-predators in many coastal and oceanic environments, feeding on fish, squid and crustaceans.
Check out this video of tuna from the Blue Planet II series.
Several species have been placed on the IUCN Red List of Threatened Species. For example, Northern Atlantic bluefin tuna is listed as endangered, yellowfin and albacares as near-threatened, and bigeye as vulnerable. Several tuna species spawn in the Gulf of Mexico due to its warm temperatures and unique hydrographic features improving the survival of their eggs and larvae.
So what exactly am I studying for my thesis?
First, I am identifying features that describe the early life stages of different tuna species. The morphology (“the study of form” or appearance of physical features) of tuna early life stages is poorly-described. Collecting fishes at these small size classes (3-125 mm SL) is very rare due to limited sampling across their wide-range of habitats. However, it is extremely important because if we do not know how to identify a fish when it is young, we cannot protect it and ensure it lives to its adult reproductive stage. So, my first task was to create an identification guide for these small fishes. The key features used for identification include: pigmentation patterns, body shape, ratios of different body parts, and fin ray counts.
To date, I have identified 11 different tuna species. These include: little tunny, blackfin tuna, bluefin tuna, yellowfin tuna, frigate tuna, bullet tuna, skipjack tuna, wahoo, Atlantic chub mackerel, Atlantic bonito, and king mackerel. Pictures of these fishes are included below. You can see how differently their early life stages look compared to their adult stages.
Larval and adult little tunny.
Larval and adult blackfin tuna.
Larval and adult king mackerel.
Larval and adult wahoo.
The second part of my project is to identify the spatiotemporal distributions of larval and juvenile tunas. Once we know what species we have, then we can identify where it is found, in what season it spawns, what type of environmental features it prefers, and so on. Basically, I am gaining knowledge about its habitat preferences, so we can help protect future populations and increase recruitment levels.
There are some small tuna species such as little tuna and blackfin tuna that do not have stock assessments nor management plans currently developed. Thus, learning about the environmental conditions that affect their distributions is essential in assessing their populations. It is evident that we still have a lot of knowledge to gain about these size classes.
This summer, I participated in an ichthyoplankton cruise in the Gulf of Mexico. Left: Jason and I are collecting organisms from the bongo net. Middle: I am holding a juvenile frigate tuna collected with a dipnet. Right: I am identifying a larval tuna under the microscope in the lab onboard.