Nina Pruzinsky is a graduate research assistant in Dr. Tracey Sutton's Oceanic Ecology Lab at Nova Southeastern University. She is interested in researching poorly-studied life stages/species/communities. By doing this, her goal is to provide information to conservation and management efforts that can be used to protect and maintain species populations. Nina gets the opportunity to work with fishes throughout the water column; she not only works with deep-sea fishes in Dr. Sutton's lab, but she also studies tuna early life stages in the epipelagic zone for her thesis. Nina's Master's thesis is entitled "Identification and spatiotemporal dynamics of tuna (Family: Scombridae; Tribe: Thunnini) early life stages in the oceanic Gulf of Mexico." This topic allows her to investigate the population dynamics of taxonomically-challenging early life stages of these ecologically, economically and recreationally important fishes.
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.
Left to right: back: Jessica, Alex, Michelle, Cori, Travis, Jillian, and Nina; front: Jason and Rich
HAPPY 4th of JULY!
Scientists still get to celebrate while we’re out at sea! Check out our tattoos! :)
Today is our last day of sampling. We started bright and early again at 6am. It rained a bit, but it was accompanied by a full rainbow arching over the boat. Nice way to start off the morning!
You guys are probably wondering how we collect all of the larval fish I showed you on the last blog post. Well, we deploy a bongo net off the back of the boat and a neuston net off the side. Both nets are brought on board and the samples are washed down into the codends. The contents of the codends are rinsed/poured and put into our sample jars. The samples are brought into the wet lab for a closer look and a potential photo. Some of the larger specimens (e.g., tunas, swordfish) are frozen for genetic analyses.
I set up a GoPro around the boat to show you guys how we sample at each station. Let’s take a look of some of our scientists at work:
Bongo nets and the sunset last night. Neuston net.
Rich is collecting water for the YSI and for the food web study. Nina is reading the water's temperature, salinity, and dissolved oxygen.
Rich, Nina, Jillian, and Jason are retrieving the bongo nets. Everyone's rinsing down the nets, while Michelle is recording the
Jillian is pouring her plankton sample out of the codend. Jason and Nina are rinsing the bongo nets.
Nina and Jessica are putting the sample into the jar. Jessica is looking at a larval tuna under the microscope/taking a picture.
Alex and Cori just retrieved the neuston net. Jillian, Alex, Cori, and Travis are sorting the neuston net sample.
Jason and Travis sorting through Sargassum. Jason and Alex looking at our catch!
Dr. Michelle Sluis is the PI on the cruise. She is recording the data for each tow (e.g., start time, location, etc.) in the pictures above.
Hope you enjoyed the pictures!
Last night we cruised towards our southern transect. We arrived at our first station and began sampling at sunrise (6am). We've hit 10 stations so far today! We collected many of our targeted species and more!
On the boat, we use a camera attached to our microscope to help us take pictures of the tiny fish. Here's some of our catch:
Alex found a siphonophore.
Cori, Travis and Jillian on deck and ready for the next tow!
All smiles here!
My name is Nina Pruzinsky. I’m out in the northern Gulf of Mexico with Texas A&M sampling for fish larvae on the R/V Pelican. We’ll be out here from July 1-5th. The scientists onboard include: Dr. Michelle Sluis (TAMUG), Jessica Lee (TAMUG), Travis Richards (TAMUG), Cori Meinert (TAMUG), Jillian Gilmartin (TAMUG), Alex Southernland (TAMUG), Jason Mostowy (TAMUG), Richard Jones (FAU) and Nina Pruzinsky (NSU).
We left the port at LUMCON at midnight on June 30th and traveled to the first station (Station 48) during the night. We started our sampling around 10am yesterday. We finished nine stations during the day and did two night tows. During the day we are using a neuston net and bongo nets to sample for larval fish. The neuston net tows for 10 minutes at the surface and the bongo nets sample to about 100 m depth. At night, we only tow the neuston net. This way, we can compare the differences between day and night tows at the same station. Additionally, Alex is sampling for gelatinous zooplankton (jellyfish) for genetic analyses, Jillian is Gtowing another plankton net to look at the community structure of zooplankton, and Travis is collecting water samples in order to characterize the food web in the Gulf.
Yesterday we caught tunas, billfish, dolphinfish, flyingfish, eel larvae, remora, frogfish, triggerfish, pufferfish, rough scad, lanternfish (at night) and more! Check out the pictures below! As you can see, all of our fish are extremely small!
Today we started sampling at sunrise around 6am and have completed three stations. We already caught some tuna and dolphinfish larvae!
Stay tuned for more pictures and updates on the cruise!
R/V Pelican before depature.
Larval dolphinfish (mahi-mahi).
Michelle and Cori preparing the neuston net.
Jillian setting up the plankton net along with the bongo nets.
We also were able to dip net a juvenile tuna last night for my thesis!
All nine of us have a specific task once the boat stops at a station. Travis and Jeff collect water samples to bring back to TAMUG; the water samples are filtered in order to characterize the food web in the Gulf. We also gather environmental data, such as salinity and temperature at each station.
Travis and Jeff collecting water samples
The bongo net and neuston net sampling methods are very similar. They only differ in mesh sizes—this allows us to catch different species along with fish of different sizes. Once the nets are brought on board, we thoroughly rinse all the fish to the bottom of the codends. Then the codends are emptied into a bucket, filtered through a net, placed in their station’s designated jar and preserved. The fish are identified back in Dr. Rooker’s lab at TAMUG.
|Retrieving the bongo nets||Rinsing the net|
|Emptying the codend||Jarring the sample|
If the fish is in good condition, it is brought to the dry lab and Kim takes a picture of it. Like this ribbonfish...
We were up early today so we could get our nets in at sunrise! It was 5:54am when we deployed the bongo nets. So far this morning, we completed 3 stations! We’ve been catching a variety of fish in our samples! Here’s a few pictures to show you guys what we are seeing:
Hello from the R/V Blazing Seven!
We are a group of eight student/scientists headed by Dr. Jay Rooker from TAMU - Galveston. We will be conducting ichthyoplankton (e.g., larval fish) tows for the next five days!
Due to some last minute repairs, we had a delayed start yesterday. However, this allowed us to set up and secure all of our nets while we were still docked at Port Fourchon. We left the dock at 1pm yesterday and arrived at our first station at 7:50am today. In order to sample a station, we deploy the bongo nets to 100 m followed by the neuston net at the surface. The bongo nets are towed for 4-8 minutes, and the neuston net is towed for 10 minutes. Once the nets are retrieved, our job is to sort through and jar the samples.
|Bongo nets||neuston net|
We’ve collected several larval fishes in the nets so far. At the first station, we collected a larval mahi-mahi and a larval sargassumfish. We also caught several larval tuna, to my excitement (since I am studying them for my thesis), and we are hoping to catch more! Unfortunately at Station 3, we had to replace our nets since it ripped while it was being towed, but the new net is functioning perfectly! At Station 8, we collected a swordfish! In all, we completed 11 stations today. It was a very successful first day and we’re looking forward to sampling tomorrow! Check back tomorrow for more pictures!
Check back tomorrow for more pictures!
On Friday, March 4, 2016, Mike Novotny and I visited Mr. Kyle Lendick's 6th grade Marine Science classes at New River Middle School. The three classes spent several weeks completing DEEPEND's grade 6-8 lesson plans (found in the Education/Outreach section under Education, Resources, Lesson Plans) before our visit, so the students had already obtained a knowledgeable background regarding the deep sea and our research. Upon our arrival, we could tell that every student was very excited to learn more about our experiences as DEEPEND members.
To start, Mike and I briefly explained how the Deepwater Horizon Oil Spill influenced the need for research and baseline data in the Gulf of Mexico and how we were sampling the Gulf's ecosystem. The students found the discrete depth sampling of the MOCNESS net to be very interesting, and throughout our discussions, I stressed the term diel vertical migration. This was a new term for most students, and they were shocked to hear that it is the world's largest migration! After our short presentation and tons of questions, we split into two groups to talk about at the deep sea fishes we brought in to share with them. With each specimen, we stressed the importance of the adaptations it uses to survive in the deep sea. The students loved the hands-on experience, and their questions were endless! Overall, I had an amazing time teaching the students about the work that we do for the DEEPEND Consortium. It was great to see how students as early as 6th grade were curious about life in the deep sea.
Fun with deep sea fishes!