NOAA Teacher at Sea
Chris Murdock
Aboard NOAA Ship Oregon II
June 7 – 20, 2017
Mission: SEAMAP Groundfish Survey
Geographic Area of Cruise: Gulf of Mexico
Date: June 19, 2017
Weather Data from the Bridge:
Latitude: 29 20.49 N
Longitude: 94 3136 W
Air temp: 30.3 C
Water temp: 29.1 C
Wind direction: 175.74 degrees
Wind speed: 9.5 knots
Wave height: 1 meter
Sky: Overcast
Science and Technology Blog
Counting the amount of fish in the sea is an incredibly daunting task. After all, the oceans do cover the majority of our planet. This is however, an absolutely essential task if we are to protect these fragile ecosystems. To accomplish this, the trawl catch must be sorted. Once each trawl is brought onto the deck, the science crew takes over. We are responsible for sorting the catch. Before we do that, we must weigh the entire catch prior to sampling.
That not only gives the scientists important information about the abundance of life at each station, but it also allows the watch leader to see if we can cut the catch. This means that the sample size is larger than what is needed, so we cut the total catch in half with a few exceptions. The other option would be to sort and record the entire catch, and that happens anytime the total weight is under 25Kg. First and foremost, we never leave out a species, so in the process of cutting the catch we sort through to look for species with only one individual present. After we pull out individuals, we then pull out all Peneaus (commercial shrimp) species. Finally, we pull out all species that are labeled as “select” in our program. This means that a scientist has particular interest in them back on land, and we are required to gather specific data about every individual of that species caught. Some examples of those that we have come across so far are all snapper species, as well as the Sphryna tiburo (the bonnethead).
Once the catch is sampled, we can then begin to sort the catch. We sort everything into a series of buckets, all into different species. Once the catch is successfully sorted, we need to count every organism represented for EACH species. Sometimes this can be as little as one individual. Other times there can be as many as 2000 individuals! Each different species’ total weight and count is then added to a program called FSCS (Fisheries Scientific Computer System and pronounced “fiscus”), which automatically records various aspects like weight and length that will eventually be entered into a national stock assessment database. Check out this video of the Oregon II crew sorting a catch: https://www.youtube.com/watch?v=yKLPv2W3Ao4
There are two roles we play in the sorting process: The “cutter” and “recorder”. The cutter’s job is to actually measure the fish, while the recorder’s job is to pull the correct species up and to record the sex and maturity of the fish being sorted. Let me start by explaining the cutter in more detail. The cutter will take a fish and line it up snout to tail on a magnetic measuring board called a Limnoterra machine.
Using a magnetic wand, you press it onto the board to record its length. The way to measure a species varies greatly from species to species. Some examples of lengths are total length (From snout to tip of tail), standard length (from snout to the end of the body, just before the caudal fin begins), Fork length (From the snout to where the caudal fin “forks”) and width (typically done with crabs, and is the width of its body).
Once the length is recorded, it is weighed and then sexed. To sex a fish, you make an incision from the anal opening towards the anterior end (towards the head). Females have two sacs typically full of translucent eggs, where males have two thin sacs full of white sperm. If the fish is immature or too small to tell, a mark of “unknown” is assessed. Some fish can also be assigned a maturity level. This ranges from running ripe (spawning) or spent (already released eggs/sperm). Again, a mark of unknown is available, but commonly we have to mark “not taken” because assigning maturity can be very difficult for small fish.
The recorder is responsible for selecting the correct species in FSCS and then making sure the proper length, weight, sex and maturity are all recorded. Typically the recorder instructs the cutter what to do. For most species, only a length is required and weight/sex/maturity are taken every six organisms for a total number of 20. That means that even if we had to count 800 Loligo plei (a type of squid) we only have to measure up to twenty. If the species was marked originally as select, we take a weight and sex of every individual. The recorder is also responsible for printing labels for species that are to be kept. Not every scientist has the ability to be on every research cruise, so typically certain species they want to study further are marked into FSCS. Once we obtain the species, we set aside the number they desire, label them and place the total amount into the freezer. This is absolutely vital to perform more complex research like diet and genetic analysis that simply cannot be done on the boat in real time.
Once every species is entered and measured, we run a station check to confirm that each species is accounted for in the system and that all the measurements add up. If weights fluctuate too greatly, or total numbers are higher or lower than originally stated, we must go back in and correct this issue. As soon as it is confirmed that all numbers look good we dump the haul back into the water. Ideally, we try and return as many species as possible alive, but this simply is not a possibility for a majority of the organisms we pull up. Understandably, this is a hard concept for a lot of people to comprehend. Make no mistake, studies like this are ensuring the long-term health of the Gulf of Mexico, and every scientist on this ship has the best interest of ocean life in mind.
Personal Log:
I have really loved my time aboard the Oregon II so far. Each day we pull up something new that I haven’t seen before. At first I thought 12 hour shifts would go by very slowly, but in fact it has been the opposite. Almost every night after my shift I find myself staying back and watching the next few trawls come on deck. The differences of day versus night catches are not surprisingly very different. Just like on land, it is a whole new planet at night under the sea. The night shift so far has gotten a bigger variety of shrimp, where we typically get the larger diurnal fish that are active during the day. The day shift also has the luxury of seeing the transitional period at dusk where a lot of the species that are active during the day travel to the bottom and the species normally inactive during the day begin to become active. Our total catches generally are smaller in a weight sense, but we routinely have 40-50 different species in every single trawl.
I am starting to fall into the rhythm of things on board too. I repeatedly hear that the Oregon II is the smallest and eldest ship in the fleet, but that the crew on here is like family. I have nothing to compare it to in terms of size, but this boat truly does feel like a family. That is one of the many reasons I love the school staff and students at Regina, so I could not picture being on a better ship. I haven’t known any of these people for more than a week, but I feel like I know each one of them on a personal level and that makes this entire experience so much more enjoyable.
I have always been a huge shark fan. Anyone who knows me can attest to that. There is something about the power of sharks that fascinates me. I also think they are incredibly misunderstood creatures that get a terribly bad rap for being especially good, evolutionary speaking. Their lineage dates back hundreds of millions of years, so it is not surprising, yet people take their viciousness the wrong way. Part of me wanted this cruise to be focused on sharks because of my passion for them. Andre told me I would more than likely get to see a shark or two in the course of the weeks at sea, but that they are typically rare to pull up in this kind of research cruise. You can imagine how happy I was when we pulled up those two bonnetheads! I said to myself “this is it. Soak this moment up because you probably won’t get another moment like this again”. Then yesterday happened.
Our first haul of the day was quite large, and as I ran out to help get it on deck I grabbed a few buckets to get ready. As the net was being emptied I saw something drop that was noticeably larger than the rest of the stock. I shook the bucket to see it better, and to my amazement an immature sandbar shark was staring up at me! I couldn’t believe it. There was even a pretty decently sized Moray eel, (Insert species)!
The next catch wasn’t anything special, but after that things got interesting. The deck came over the radio “You guys are going to want to get out here, this next catch is a big one.” So the scientists all went out, we put on our hard hats and life vests and started preparing the buckets. I fired up my GoPro and got ready. As soon as the cod end broke the surface you could see the characteristic anvil-shaped head of the bonnethead shark. The further the net came up, the more anvils I saw. Two, three, four, FIVE bonnetheads I counted as we brought them on board. I soon found out that I had miscounted, and as we emptied the net we actually had ten sharks. Ten adult sharks were an arm’s length away from me. The awe was short lived, and we had to get back to sorting the catch. I barely had time to process all of that when we got another monster haul.
As the next catch was emptied on deck, we got another big surprise: NINE MORE BONNETHEADS! Let that sink in for a second. A shark lover from Iowa was getting the experience of his dreams, and within the span of three hours we pulled up twenty sharks. The sandbar we were able to safely release, but all of the bonnetheads we kept for research. Why keep so many sharks for research purposes instead of release them you ask? Many of you are probably confused and wonder how this could be good for their population. The answer is quite simple: We need to learn as much about these species as possible if we are going to accurately protect them, and sometimes that requires looking at stomach contents or running genetic samples. By understanding what they eat and where they have been, we can make a more comprehensive plan to protect these amazing creatures in the future.
As I enter my final five days on board the Oregon II, I am trying as hard as I can to take in every second of this experience. Truth be told, I expected two weeks out at sea to feel like a long time. In reality, I find myself scrambling to hang on to my time here. I may never get another opportunity like this again, and being able to show my students how it is not too late to save the oceans is incredibly humbling. For those of you back in Iowa reading this and wondering “how does this all relate to me”? Stay tuned to further posts and you might just be amazed at how a small flyover farming state like Iowa can have monumental impacts on life in the Gulf.
Did you know?
Lizard Fish (Pictured here is Synodus foetens the “inshore lizard fish”) are equipped with multiple rows of interior razor-sharp teeth that are used to pull prey further into their mouths as they feed.
Species Identified Today:
