Weedline: A Sargassum Blog

PS-19-05 Daily Log

June 4, 2019 (Day 8)*

*Note: these will be posted on a one-day delay, i.e., this report is for yesterday’s activities. 

We hope you enjoyed yesterday’s blog entry. Remember we also post throughout the day on the @larvalfishlabTwitter account, so follow us there as well!

Well here we are, Day 8, the last day of sampling of our last cruise for this project. Tomorrow will be steaming home, packing and unloading samples, gear, and supplies (probably in the rain) –you know, boring stuff. So this will be the last installment of our cruise blog.


Photo: Carla Culpepper

Through the magic of remote sensing, and the keen eyes of the guys on the bridge, we woke this morning to a series of pretty large Sargassummats located approximately 30 nautical miles south-southwest of the birdsfoot delta. Okay, there’s a lot of science that goes into these satellite images, but they seem pretty magical to us. The mats were teeming with fishes. Large Mahi Mahi were schooling between mats, and we could see many juvenile jacks, filefishes and triggerfishes under the Sargassumcanopy as we cruised closely by to inspect potential sampling targets. All indications were that this was going to be another great day.


Graduate student, Courtney Stachowiak, takes measurements of a fish collected by sabiki fishing.

We began as usual by collecting CTD profile data and water samples, followed by a near perfect neuston net tow along the long edge of a large Sargassum mat. This tow yielded numerous chubs, jacks, filefishes, and other species we’ve grown accustomed to in the weedlines. We scooped up a pretty good chunk of the mat, so it took several hours to rinse through the algae and collect the fishes and invertebrates. Sargassum mats drifted by the vessel as we worked, and one of these mats had a young green sea turtle rafting on top. It’s flippers spread out, it looked like it was asleep, or at least oblivious to our presence. We tweeted a picture of the carefree turtle, and friend-of-the-lab and turtle expert Dr. Kate Mansfield (@UCFTurtleLab) replied that they commonly see this behavior. Floating on top of the Sargassum hides them from predators lurking in the waters below, and the warmth provides a perfect and cozy nap environment. So fair winds and following seas, little turtle!


A green sea turtle spotted from the boat resting on a Sargassum mat (Photo: Sandra Huynh)


The science team look for fish collected in the purse seine. (Photo: Sandra Huynh)

We worked in a Sabiki hook-and-line sampling set before lunch, and caught quite a few juvenile amberjacks and Blue Runners (Hardtails). Having still not collected many triggerfishes, in spite of our best efforts, we pulled out the (sometimes loved, sometimes dreaded) plankton purse seine! Conceptually, the idea is simple. Our seine is a 10-m long by 3-m deep curtain of 1-mm mesh that can be used to encircle a small patch of Sargassum and “pursed” to collect larger fishes that easily evade the neuston net. Deploying the purse seine off the small boat, however, does take some practice and we were admittedly rusty. The first attempt actually went very well, and collected a few smaller juvenile amberjacks as well as a Grey Triggerfish (yes!). The next several attempts, however, were not so great. Finding the right size mat is important, and many little things have to go right for it to work, and we just didn’t have the best of luck today. But it was a valiant effort by the small boat team on yet another very hot day, and their efforts are greatly appreciated.

By mid-afternoon we were faced with a decision as to what to sample next. Based on the remote sensing imagery, we appeared to be very close to the “tide line”, where the green coastal waters abut the dark blue offshore waters, and there appeared to be high Sargassum biomass. We steamed north in search of Sargassum along this feature, but could not find any significant weedlines. After searching for a couple of hours, we turned back south to find open, blue waters again just before sunset and completed two deuceton net tows, the last field collections for our project.


The science team celebrate their last net tow of the cruise (Photo: Sandra Huynh)

It was a bittersweet feeling, leaving that last station. There’s a lot left to do on this project now that the field collections are completed, and we will be working on our data analyses over the next year. But there’s just nothing like the thrill of being on the water, searching for Sargassum, and wondering what will come up in the net next time. Of the four cruises, this has been one of the most successful, as we’ve sampled everyday we’ve been out. Just a tremendous job by the science team and by the vessel crew.

Science Team 1

Science Team members: Eric Haffey, Caitlin Slife, Dr. Kevin Dillon, Emily Gipson, Glenn Zapfe, Patricia Colon, Courtney Stachowiak, Sandra Huynh

Science Team 2

Science team members: Dr. Mengqiu Wang, April Hugi, Glenn Zapfe and Carla Culpepper, Zabe Premo, Olivia Lestrade, Minghai Huang


R/V Point Sur crew: Marty Chauvin, Casey Hurt, Kevin Piazza, Josh Jansen, Josh Bierbaum, Nic Allen, J.D. Ellington

We hope you enjoyed our blog. Should you have any questions, please feel free to get in touch. And while this is the end of our cruise blog, it’s not the end of the project; we will do our best to provide additional project updates on our website and twitter page, so please stay in touch.


Dr. Frank Hernandez (Photo: Sandra Huynh) 

Thanks again, it’s been great sharing our work with a wide audience.

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Weedlines: A Sargassum Blog

PS-19-05 Daily Log

June 3, 2019 (Day 7)*

*Note: these will be posted on a one-day delay, i.e., this report is for yesterday’s activities.

We hope you enjoyed yesterday’s blog entry. Remember we also post throughout the day on the @larvalfishlabTwitter account, so follow us there as well!

Another scorcher today on the water. The sun was unrelenting, and there was barely a breeze out today. The only upside was the near glass-like sea state, which makes for nice working conditions, especially for our small boat operations. It’s hard to imagine a vast area like the Gulf of Mexico having such conditions, but the water’s surface was so smooth it was actually difficult to locate Sargassumin the distance, as there were no wave crests and troughs to break the horizon. Fortunately, we found ourselves surrounded by Sargassum yet again at the northernmost extent of the Loop Current in an area located approximately 70 nautical miles south-southeast of the Louisiana birdsfoot. So of course we got right down to work.


The neuston collecting sargassum in the beautiful blue water (Photo: Sandra Huynh)


PhD student, Zabe Premo, filters water in the R/V Point Sur lab. (Photo: Sandra Huynh)

First, we collected our CTD profile and water samples at the edge of a large Sargassum weedline, and with no wind it was relatively easy to stay on station without disrupting the algae. As the sun rose higher in the sky, the ‘blueness’ and clarity of the water became apparent, and we could see schools of adult Mahi Mahi swimming at depth from patch to patch. We then towed our neuston net along the same weedline and collected numerous juvenile fishes, including Whitespotted Filefish, Grey Triggerfish, Scrawled Filefish, and small jacks, among other species. The small boat team departed to take reflectance observations in Sargassumand open water habitats, and those remaining on board completed a Sabiki hook-and-line set. For the first time during the cruise, we did not catch many fishes with the Sabiki rigs, perhaps only five or so amberjacks. We also did not see a lot of larger juveniles swimming around–perhaps due to those adult Mahi cruising the weedlines…..?


R/V Point Sur Marine tech, Josh Bierbaum, was able to snap this beautiful picture of dolphins leading the small boat back to the mother ship. (Photo: Josh Bierbaum)

Or perhaps due to another set of visitors that arrived shortly after our fishing set. While fishing we could see a small pod of dolphins swimming, leaping, and all. around having a good time in the distance. About a half hour or so after our fishing set, they had made their way to the vessel, and as best as we could tell these were rough-toothed dolphins (we have lots of pictures if any experts want to help us out!). One of the dolphins seemed to be having a particularly good time, and we watched as it repeatedly tossed an object in the air and retrieve it. It looked to be a small fish, and once we captured a few pictures (thanks to Casey Hurt’s excellent photography skills) we could actually identify it as a Grey Triggerfish, one of our target species! We’re not sure if the dolphin ever consumed the triggerfish, or if it just toyed with it for a while. We did see some of the larger dolphins in this group chase and feed on adult Mahi Mahi, which was exciting. We often encounter dolphins at sea during our cruise, but mostly as they are riding our bow as we transit between stations. We’ve not seen them forage within the mats before, though given the number of potential prey within Sargassum, this is not surprising. And whether dolphins use Sargassum habitats regularly or opportunistically is unknown. In any event, today was once again a reminder of how much there is yet to learn about the role of Sargassum in offshore environments.


The talented R/V Point Sur Second Mate and photographer, Casey Hurt, was able to snap this amazing picture of a dolphin playing with a trigger fish. 

After all of the marine mammal excitement, and a quick lunch, we decided to collect another neuston sample in this region. This was one of those decisions that seemed like a good idea at the time, but given the heat and the amount of time it took to process a second neuston sample, the science team was pretty worn out at day’s end. After a well-deserved dinner break, we collected our open water station samples, which are not nearly as time-consuming and laborious, as well as a pair of deuceton net samples (and more billfish larvae!). There was a particularly nice sun set this evening, which always puts a smile on your face.


Hernandez lab members spend countless hours rinsing and sieving down the sargassum to preserve for analysis back in the lab. (Photos: Sandra Huynh)

It’s our seventh straight day of sampling, and the weariness is starting to set in, though I know we’ll all be sad when we start steaming for home tomorrow evening. Tomorrow we will likely sample again near the birdsfoot region, perhaps along the ‘tide line’, or Mississippi River plume edge, where there is usually a convergence zone.

So please join us again as we begin to wrap up our final cruise.

Weedlines: A Sargassum Blog

PS-19-05 Daily Log

June 2, 2019 (Day 6)*

*Note: these will be posted on a one-day delay, i.e., this report is for yesterday’s activities.

We hope you enjoyed yesterday’s blog entry. Remember we also post throughout the day on the @larvalfishlabTwitter account, so follow us there as well!


Photo: Sandra Huynh

Welcome back to the offshore waters of the Gulf of Mexico, where the price you pay for calm seas and light winds is blazing sun and stifling heat. We are going through sunscreen and Gatorade like crazy, but having fun and getting lots of great data on this, the last cruise for our NOAA RESTORE Sargassum project.

Last night we steamed west, having earlier followed the southward flow of the Loop Current to within 100 miles of the Cuban EEZ! Our sampling permits don’t work down there, so we needed a new direction. Our westward track had us crossing the ‘loop’ over night, and by breakfast we had arrived near the northerly flow of the Loop Current. Finding ourselves in relatively open water, we decided to do our open water station first. Following our CTD cast and water sample collections, we towed the neuston, deuceton, and frame trawl nets, and in each instance we collected relatively few larvae or juvenile fishes. So pretty much a ‘desert’ in the open water area inside the ‘loop’ today, at least in our location.


April Hugi records data which is one of the most important jobs on a research cruise. (Photo: Sandra Huynh)

After completing the open water ops, we steamed further west to get closer to the northerly flow of the Loop Current. We decided to sample in a region where there were numerous, small-to-medium Sargassum patches. After collecting our CTD and water samples, we towed our neuston net along a small weedline and had one of our largest fish hauls of the trip, with juvenile Bermuda Chubs, Sergeant Majors, jacks, Orangespotted Filefishes, and Sargassum fish, among others. This sample was processed while the small boat team collected reflectance measures from Sargassum and open water habitats. While floating among the Sargassum patches, we did not notice many larger juvenile fishes, and we did not see many during a quick scan of our camera rig video. Because of this, and the lack of any larger patches in the area, and the fact that it was getting late in the day, we decided to forgo our Sabiki fishing set. We tried fishing the baited Sabiki rigs for 10-15 minutes to see if we could collect anything at all, and we did manage to get a Rough Triggerfish and a Blue Runner for diet analyses, so not a total loss. But in general, the larger juveniles were lacking in this area, or at least unavailable using our samplers.


IMG_2161Having had a long day, we relaxed for a few minutes before dinner, and afterwards we collected to deuceton net samples along the eastern edge of the north-flowing portion of the Loop Current. These worked well as we collected several more billfish larvae and their zooplankton prey field. The early evening was spent cleaning up, refreshing the ethanol preservative in collected samples, and other routine chores to ensure our data are secure and that we are ready to do it all again tomorrow.



The science team launches the ‘dueceton’ net at sunset.  (Photo: Sandra Huynh) 

And speaking of tomorrow, we’re setting a course north to a region just south of the Louisiana birdsfoot, where our remote sensing imagery suggests relatively high Sargassum biomass. It’s a long transit, but we’ll have a little assistance from the Loop Current!



Weedlines: A Sargassum Blog

PS-19-05 Daily Log

June 1, 2019 (Day 5)*

*Note: these will be posted on a one-day delay, i.e., this report is for yesterday’s activities.

We hope you enjoyed yesterday’s blog entry. Remember we also post throughout the day on the @larvalfishlabTwitter account, so follow us there as well!

IMG_2124 2

Early in the morning R/V Point Sur deckhand, Kevin Piazza, spotted what ended up being the largest Sargassum patch that we have ever encountered to make for a great day of sampling! (Photo: Captain Nicholas Allen) 

Wow, today we found the Mother of all Sargassum mats approximately 240 nautical miles south-southeast of Pensacola, Florida. Unfortunately we did not have a small drone or other means of accurately estimating its size, but it was the largest we’ve seen to date in our project. It was located in a region where the Loop Current is essentially running in to itself, and perhaps on the verge of pinching off an eddy (though the Loop Current is notoriously unpredictable). Here there are currents converging in this particular region, which makes for a high probability of Sargassum aggregation, and we were fortunate to find lots of it today.


Small boat ops embark to set the camera rig and collect water within the sargassum using a Beta Niskin sampler. (Photo: Sandra Huynh)

The size of the mat was pretty daunting, and we were not sure where to start at first. We decided to drop off a camera rig along one edge of the mat to get a feel for what types of fishes were present. While the camera was recording, we motored to the other end of the mat and collected our CTD profile and water samples. Afterwards a quick scan of the


The CTD provides many sorts of samples for the science team and becomes a very busy place upon recovery. (Photo: Sandra Huynh)

video revealed that the Sargassumwas very ‘thick’, nearly a meter deep. This reduced the visibility under the mat, creating a dark blue/black shaded environment under the canopy. High abundances of fishes were observed, but unfortunately we could not identify them due to the poor visibility. We then collected a neuston sample by towing across one of the mat edges, and collected a number of fishes, including Tripletail, filefishes, and small jacks, among others. This was one of our largest fish collections in the neuston net so far this cruise. Given the many fish we were seeing, we were excited about our hook-and-line Sabiki fishing set. And there was certainly a lot of action there, as we reeled in the amberjacks, sometimes four or five at a time! There were other fish there, including triggerfishes, but they could not beat the “AJs” to the hooks, so we did not sample them well. But overall, we had quite a successful sampling set here.



Co-investigator Glenn Zapfe, graduate student Courtney Stachowiak, R/V Point Sur marine technician Josh Bierbaum, and graduate student Minghai use the sabiki rigs to catch juvenile Sargassum associated fishes. 


Glenn Zapfe and Carla Culpepper look on as Emily Gipson and Eric Haffey assist with the launching of the ‘deuceton’ net. (Photo: Sandra Huynh)

Once again finding open water was a challenge, though we managed to find gaps in the Sargassum to collect our CTD profile, water samples, and our neuston net sample. Unfortunately we did not collect many fish in the neuston net. However, the ‘deuceton’ came through with lots of larvae tonight. In fact, two deuceton tows collected over 40 billfish larvae! With the adjoining smaller net we collected common prey for billfish, including copepods and cladocerans, so we’re excited about studying their trophic ecology in this region of the Gulf.

As we’ve done the past few nights, we decided to tow the frame trawl to end our evening. Now that we were in >3,000 m water depth, we decided to send the net a bit deeper than usual, and wow, did we collect some wonderful specimens! We’ll tweet some images of these in the coming days as we sort through them, but among the highlights was a beautiful, deep ocean cusk-eel larva with a long, trailing gut (which is thought to mimic siphonophores, and therefore offer a measure of protection from predators–though that’s only a guess as to its function). We caught several very long (>150 mm) eel leptocephali, as well as lanternfishes, larval surgeonfishes, and many other species we’ve yet to identify. So stay tuned for more cool pics!


Caitlin Slife and Eric Haffey check out some critters collected with the Methot net. (Photo: Sandra Huynh)

We’ve passed the midway point of our cruise, which has already been a great success by most measures. Tomorrow we will likely sample in the ‘lower’ Loop Current region again, but perhaps to the west of our current location where the Loop Current is running towards the north. Afterwards we can ride this conveyor belt towards home. But we have a few days yet, so more Sargassum collections are ahead. Thanks for following along!



Weedlines: A Sargassum Blog

PS-19-05 Daily Log

May 31, 2019 (Day 4)*

*Note: these will be posted on a one-day delay, i.e., this report is for yesterday’s activities.

We hope you enjoyed yesterday’s blog entry. Remember we also post throughout the day on the @larvalfishlabTwitter account, so follow us there as well!

Overnight we steamed from our previous location towards the west to an area roughly 140 nautical miles south-southeast of Pensacola, Florida. As we woke up on Day 4 we found ourselves in an area with quite a bit of scattered Sargassum clumps and mats. The only question was which features to sample, so again, we’ve had great luck in locating Sargassum during this cruise. Seas were very calm, less than 1-foot in wave height, and slight winds. All of this pointed to perfect conditions for sampling. We also knew it was


A sea turtle with larval jacks in tow (Photo: Sandra Huynh)

going to be another very hot day on the water. While scanning the horizon and choosing potential Sargassum mats to sample, we were greeted by a large loggerhead sea turtle that arrived with its own entourage of juvenile fishes swimming under and behind it. It the open ocean, you get flotsam wherever you can, and these juvenile jacks seemed content to follow the turtle, even in the presence of ample Sargassum. After checking us out for few minutes and finding us relatively uninteresting, the loggerhead swam off with her/his minions trailing behind. Out of an abundance of caution, we turned and idled away in the opposite direction to choose a Sargassum feature to sample and minimize any further potential interactions.



Graduate student, Courtney Stachowiak, collects abiotic data from the ship’s many data acquisition systems. 

After we collected water samples and our CTD profile, we deployed our neuston net and sampled along a line of small-medium Sargassum patches. We successfully collected several juvenile Grey Triggerfishes (yeah!), as well as more Sargassumfish and small jacks. After processing the neuston sample, the small boat team departed to collect reflectance observations and the remaining members of the science team completed a Sabiki rig hook-and-line sampling set. Numerous adult mahi mahi were cruising the weedlines, so we had to reel the fish in quickly to land them. Again, we collected over 30 juvenile amberjacks  (species to be determined), but no other species. We decided to opportunistically sample by continuing to fish our Sabiki rigs, but this time with little bits of squid on the hooks. In doing so, we attracted and collected several Rough Triggerfish that we would not have collected otherwise. We may go back to this technique later, if needed.


Juvenile Almaco and Lesser Amber Jacks caught with sabiki rigs. (Photo: Sandra Huynh)

After lunch we processed the hook-and-line fishes, and collected more algal reflectance observations on the small boat before we steamed away to locate ‘open’ water, which like yesterday, was just not going to happen. We were really surrounded by Sargassum, so we did the best we could to collect water samples and a neuston net sample while avoiding clumps of Sargassum. All sampling ops went well, although we caught relatively few fish larvae in both the neuston and ‘deuceton’ net samples. There was lots of Trichodesmiumin this area as well, which can really clog nets and decrease filtering efficiency; this may partially explain the low larval numbers. In any event, we hope to find a ‘real’ open water station or two before the cruise ends, in part because we tend to find lots of cool billfish larvae in those areas (so stay tuned for that!).


A cephalopod paralarvae (Photo: Carla Culpepper)

Having completed all of our scheduled ops for the day, we gathered on deck after dinner to deploy the frame trawl again. And once again we were not disappointed! Among the many cool fish larval stages we collected were barracudina, cardinalfish, snake mackerel, eels, mahi mahi, and remora. And for inverts, a small pelagic octopus was a highlight, as well as several Ceratapsis montrosa, a relatively rare (and purple!) mysis stage of the deep pelagic shrimp Plesiopenaeus armatus. Although the larval stage Ceratapsis are relatively small, they have been found in the diets of large pelagic fishes, such as yellowfin, bluefin, and blackfin tuna!

Tomorrow we will likely continue to the south and west to search for Sargassum (and open water) habitats in the Loop Current.


A small Barracudina caught in the methot net. (Photo: Sandra Huynh)

Weedlines: A Sargassum Blog

PS-19-05 Daily Log

May 30, 2019 (Day 3)*

*Note: these will be posted on a one-day delay, i.e., this report is for yesterday’s activities.

We hope you enjoyed yesterday’s blog entry. Remember we also post throughout the day on the @larvalfishlabTwitter account, so follow us there as well!

We had another very successful day on the water, thanks to the tremendous efforts of the science team and vessel crew. As the song goes, “the heat was hot”– it was a real scorcher on the water today, but everyone persevered. Very fortunate to have such a wonderful team and a tremendous crew on the Point Sur.


Emily Gipson and Eric Haffey rinsing the Sargassum of any animals and plastics. (Photo: Sandra Huynh)

Today we were once again in the eastern Gulf of Mexico, approximately 90 nautical miles due south of Panama City, Florida. There was quite a bit of Sargassum in the area, however it was not consolidated into large mats as before, but rather long, then and often “patchy” weedlines. After searching around a bit, we decided to sample along one of these weedlines and a moderately sized mat of Sargassum. We were definitely in dark blue water at this site (salinity was approximately 36). This sample yielded numerous Sergeant Majors, Sargassum fish, and small filefishes, but unfortunately none of our target, commercial species of interest. One Sargassumfish from this sample was the smallest we’ve ever collected, about 1 cm in length (and a big
hit on Twitter, so thanks everyone!). After processing this sample and having a quick lunch, the optical oceanography group went out in the small boat to collect reflectance observations, and the remaining scientists on board attempted to hook-and-line sample a relatively sparse aggregation of Sargassum. Three small amberjacks were collected, and few other fishes were observed. Overall the habitat was just too spread out to be sampled effectively via hook-and-line, but we gave it our best effort.


The science team was very excited about spotting a Manta Ray swimming around the boat! (Photo: Sandra Huynh)

Sampling at today’s Sargassum station attracted several more visitors to the R/V Point Sur. A pair of Atlantic Pantropical Spotted Dolphins were observed swimming along a weedline, and a whale spout was observed in the distance. A pair of cattle egrets, obviously lost, circled the vessel and finally landed for a rest. And then there was the Manta Ray! It swam along the starboard side of the vessel for a few minutes, nearly surface once or twice. We did our best to get pictures but she/he was a bit shy. Still, that was a first for most of us, so we were quite happy about the visit.


A couple of cattle egrets took a rest on the vessel for a bit in the afternoon. (Photo: Sandra Huynh)

After wrapping up our sampling ops at the Sargassumstation, we moved to an ‘open water’ location, which was really ‘mostly open water’, as there were many small, fragmented clumps of Sargassum scattered about. We did our best to avoid Sargassum, but finding a true open water site was not going to happen today; we were simply surrounded. The standard ops proceeded well, including our CTD cast, water sample collection, and neuston net tow. We also completed two ‘deuston’ net tows as well; all net tows were relatively thick with Trichodesmium (also called ‘sea sawdust’), which is a cyanobacteria common in offshore, oceanic waters in subtropical and tropical areas. So we could see larval fish eyeballs in the samples, but we really won’t know what we have in these samples until they are sorted back in the laboratory.


The science team recovering the methot net (Photo: Sandra Huynh)

Having wrapped up our primary sampling ops, we decided to deploy the Methot frame trawl after dinner. This is our largest net sampler (5-square meter aluminum frame with a 3.1-mm knotless mesh net) that is towed at a relatively fast speed (4 knots) compared to other larval and juvenile fish samplers. Theoretically, the frame trawl is used to collect the more evasive juvenile fishes in the open water habitats that are too fast to be collected in our smaller plankton nets. For us, however, it has not sampled juvenile fish very well, and tonight was no exception. However, in spite of its relatively large mesh


The science team determine the identity of the larval fish with the help of a microscope (Photo: Sandra Huynh)

size, the frame trawl often collects the coolest fish larvae and invertebrates. Tonight we collected an incredible assortment of larval fish specimens, including barracudinas, groupers, flounders, eels, and lanternfishes, among others. We also collected several pyrosomes, salps, pteropods, and heteropods. What a way to end a great day on the water.


Overnight the plan is to steam towards the west and hopefully reach the northern edge of the Loop Current. So be sure to check out tomorrow’s blog post, and thanks for following.


Dr. Frank Hernandez and co-investigator, Glenn Zapfe, work together to identify some of the organisms caught in the methot net. (Photo: Sandra Huynh) 


Weedlines: A Sargassum Blog

PS-19-05 Daily Log

May 29, 2019 (Day 2)*

*Note: these will be posted on a one-day delay, i.e., this report is for yesterday’s activities. 

We hope you enjoyed yesterday’s blog entry. Remember we also post throughout the day on the @larvalfishlabTwitter account, so follow us there as well!

Now on to today’s action (Day 2), which includes several non-fishy visitors …


Some of our non-fishy visitors (Photo: Sandra Huynh)

We couldn’t have asked for a better start than the one we had today. There’s nothing quite like waking up, walking up to the wheelhouse, and seeing rafts of Sargassum all around. Our decision to take advantage of the relatively calm conditions to the east of yesterday’s sampling region really paid off. Kudos to the R/V Point Sur night crew! Plenty of Sargassum, seas less than 1 foot, and winds around 5 knots–perfect conditions.


The CTD sampling the surface water just below the Sargassum. (Photo: Sandra Huynh)

We started the day with a CTD cast, followed by a neuston tow through the weedline. The neuston tow went well. Shortly after getting the net on board, we drifted along with the Sargassum as we processed the net sample. During this time, a juvenile sea turtle (unknown species) was observed swimming away from a nearby mat towards a more distant Sargassum features. Such encounters serve as a reminder that Sargassum is home to many species, not just fishes. And it’s also the reason we take great precautions when sampling with our nets to avoid any incidental captures of turtles.


(Photo: Sandra Huynh)

Following the neuston tow, we did a standardized hook-and-line sampling set, which for us includes four anglers fishing along side a Sargassum mat for 30 minutes using small hook Sabiki rigs. We do this to collect some of the larger juveniles that typically evade our neuston net. Today it worked very well. So well in fact that we cut our fishing time short; after 15 minutes we had 35 fishes, all Seriola spp. (amberjack species), and most were likely Almaco Jacks (though we will confirm identifications later through morphometric and molecular analyses). These fishes are definitely too fast for our nets, which is why we often use multiple gear types when we sample Sargassum (and other) habitats.


Graduate student, April Hugi, dropping a sabiki line to catch juvenile Sargassum associated fishes. (Photo: Sandra Huynh)

Seas were calm enough to deploy the small boat for additional sampling operations. Using the small boat, we were able to place our floating camera rig into a large Sargassum patch, where it recorded video for approximately two hours. During this time, algal reflectance measurements were also collected from the small boat; these data are used to groundtruth and validate our remote sensing (satellite) observations, as well as improve the algorithms used to detect Sargassum from space.


Dr. Frank Hernandez (Photo: Sandra Huynh)

Having had such a great start, we decided to collect an extra neuston net sample from a very large Sargassum mat at today’s station. Here we picked up several Sargassumfish, Sergeant Majors, and a Sargassum pipefish. As with a few trips last year, we are finding the Grey Triggerfish to be elusive–we see some larger juveniles swimming under the mats at times, yet we have only collected one so far in a net, and none during the sabiki fishing. Hopefully the video survey will provide some abundance estimates for this species; again, a great example of why we use multiple gears!




The maiden voyage of the “deuceton.” (Photo: Sandra Huynh)

After collecting more reflectance data from the Sargassum mat, we set a course for an open water station where we collected water samples and a CTD profile, as well as an open water neuston sample, which was loaded with larval fishes, including larval goatfishes, which are distinctive in their countershading coloration. We also experimented with a new, “double neuston” net, or as we call it, the “deuceton net”. Like our standard neuston net, this frame has a 2 x 1 m opening fitted with a 505 micron mesh net; but the frame also has a smaller, 0.5 x 1 m opening fitted with a 150 micron mesh net. The idea here is that the larger net collects fish larvae and the smaller net will collect zooplankton prey concurrently. And it worked ! Two tows yielded numerous larvae, including several billfish larvae, and a beautiful “blue dragon” nudibranch. We’re hoping this additional net adds to our knowledge of the planktonic food webs of open ocean waters adjacent to Sargassum habitats.

It was a long day to say the least, but a very successful one. Our plan is to steam south-southeast from our current location to take advantage of favorable seas in the eastern Gulf and high Sargassum biomass.


Photo: Sandra Huynh

Weedlines: A Sargassum Blog

Meet the Scientists

We’re winding down on Day 2 of searching for Sargassum! We have a mixture of Sargassum veterans and a few new faces for this leg. Check out who’s on board and learn a little bit about our science team, and thanks for following along on our blog!

Frank HernandezDr. Frank Hernandez (Chief Scientist, Lead Investigator, USM)

Dr. Hernandez is an Associate Professor in the Department of Coastal Sciences at the University of Southern Mississippi where his research focus is in fisheries oceanography. His research interests include larval and juvenile fish ecology, biophysical processes that influence recruitment dynamics, fish-habitat associations, planktonic food webs, and the impacts of environment/climate variability and anthropogenic disturbances on the ecology of fish early life stages. He spends way too much time at his desk or in meetings, and is therefore thrilled to be going offshore again in search of Sargassum.

Kevin DillonDr. Kevin Dillon (Co-Investigator, USM)

Dr. Kevin Dillon is a chemical oceanographer and associate professor in USM’s Division of Coastal Science. His research interests include carbon/nutrient cycling and food webs in aquatic environments and the impact of anthropogenic stressors to these ecosystems. In this study he is using bulk stable isotopes (13C and 15N) as well as compound specific stable isotopes of amino acids to elucidate food web dynamics in Sargassum communities.  He is grateful for this brief escape from the lab for some well-deserved time at sea with his PhD students exploring the mysteries of Sargassum.

Glenn Zapfe (Co-Investigator, NOAA)

Glenn ZapfeGlenn is the lead of the Plankton Unit at NOAA’s Mississippi Laboratories in Pascagoula, Mississippi. He oversees the plankton portion of the Southeast Area Monitoring and Assessment Program (SEAMAP) which includes surveys conducted to provide fishery independent data for stock assessments. His interests include examining the role Sargassum plays in affecting larval abundance and distribution of commercially important species such as grey triggerfish and dolphinfish.


Carla CulpepperCarla Culpepper (Research Technician, USM)

Carla is a technician and lab manager of the Fisheries Oceanography and Ecology Lab in the Department of Coastal Sciences at the University of Southern Mississippi. Her research interests are in plankton dynamics in the northern Gulf of Mexico, particularly, the interactions between zooplankton and ichthyoplankton. This is her eighth cruise aboard the R/V Point Sur!


Eric Haffey (Research Technician, USM)

Eric HaffeyEric is a technician who joined the lab January of 2017 identifying larvae fish as part of the CONCORDE project. Prior to being a part of our lab he worked at the Baruch Field Laboratory USC in South Carolina working with planktonic samples and early life stage tarpon. He is excited to embark on his third sargassum cruise aboard the R/V Point Sur.


Olivia Lestrade

Olivia Lestrade (Graduate Student, USM)

Olivia is a Master’s student in the Fisheries, Oceanography, and Ecology lab at the University of Southern Mississippi. Her research focuses on microplastic impacts to early life stage fishes associated with floating Sargassum habitats. She has been a fish out of water her whole life and has a passion for understanding and exploring the Gulf of Mexico.


Courtney StachowiakCourtney Stachowiak (Graduate Student, USM)

Courtney is working to obtain her MS in Coastal Sciences at the University of Southern Mississippi’s Gulf Coast Research Lab. Her research is funded by the NOAA RESTORE program and is focused on assessing the juvenile fish community assemblages associated with Sargassum, and targeting important fishery species to quantify age and growth parameters. She hopes to pursue a career in fisheries research as she enjoys field sampling, and she is looking forward to her third research cruise aboard the R/V Point Sur.

Zabe PromoElizabeth (Zabe) Premo (Graduate Student, USM)

Zabe is a PhD student in the Department of Coastal Studies at the University of Southern Mississippi working under the advisement of Dr. Kevin Dillon, and is undertaking research focused on stable isotope ecology and marine nutrient cycling. She is funded by NOAA RESTORE, and her main efforts as part of this project focus on bulk and compound specific stable isotope analysis of biological samples to investigate trophic structure associated with Sargassum features. Zabe is extremely grateful for the opportunity to go to sea, and intends to unabashedly geek out with each new Sargassum sighting.

Mengqiu WangMengqiu Wang (Graduate Student, USF)

Mengqiu started the project as a PhD candidate but completed her degree and remained as a post doctoral research scientist in the College of Marine Science at University of South Florida. Her dissertation focused on studying the distributions, abundances, and transport of Sargassum in the Intra-Americas Seas and North Atlantic. Most of her study was based on “reading and interpreting” satellite images and she is eager to continue to decipher more about Sargassum with field measurements.

Caitlin Slife


Caitlin Slife (Graduate Student, USM)

Caitlin is a PhD graduate research assistant in Dr. Dillon’s chemical oceanography and biogeochemistry laboratory at the University of Southern Mississippi. She is a stable isotope ecologist whose research is focused on modeling trophic webs via bulk isotope and nutrient analysis. Throughout the year, her field work typically only goes offshore for a few days, so she is very excited to spend an extended period offshore working on Sargassum.


April Hugi April Hugi (Graduate Student, USM)

April joined the Hernandez lab as an intern in the summer of 2018 and started graduate school in the fall. She is interested in larval fish ecology, fish-habitat associations, and ecosystem-based fisheries management. Her eventual goal is to pursue a career where she can link her two passions of marine science and visual art to help bridge the communication gap between the public and the scientific community.



SAN_8450Emily Gipson

Emily joined the larval fish lab as a masters student in Fall of 2018 after receiving her bachelors from the University of Central Florida. Her thesis focuses on larval and juvenile deep-sea fishes from the northern Gulf of Mexico. She will be using gut contents and a combination of bulk and compound specific stable isotope analysis to study their feeding ecology.



Minghai Huang SAN_8220

Minghai is a Ph.D. student in College of Marine Science at University of South Florida. His current research focuses on studying the connection between the Atlantic Ocean, Caribbean Sea and Gulf of Mexico through meso-scale eddies. Most of his study was based on the numerical model output and altimetry results. He is excited to gain sea-going experience during this cruise.



Patricia Colón

Patricia is an intern who recently graduated from the University of West Florida with her Bachelor’s degree in Marine Biology. Her zodiac sign is Pisces and her favorite invertebrates are squids. She is interested in plastic pollution and how it may affect abyssal trench environments and the organisms that live there. She also likes the idea of being a professor at a university. This is her first time being on a research vessel, so almost everything excites her.


Sandra Huynh (Guest Scientist)SAN_8621.JPG

Sandra is an alumna of the Hernandez lab and is stoked about joining the lab again on her first research cruise on the R/V Point Sur as a volunteer visiting scientist. After working for the Hernandez lab, she obtained her Master’s degree in Marine Resource Management from Oregon State University and currently works for the Mississippi Department of Marine Resources at the Grand Bay National Estuarine Research Reserve, where she still works with plankton as much as possible!

Nudibranch (Sea Turtle, Guest Lovie)

NudibranchNudibranch is going on her third research cruise, courtesy of Frank’s daughter, Beatrice. Nudibranch will help in several important ways. First, she will use her sea turtle powers to help the team locate Sargassum at sea. Second, she will help scan the weedlines and ensure that our sampling region is “turtle free”, and that we are okay to deploy our nets. Lastly, she will keep Beatrice’s dad company, so that he will not be lonely and miss his family so much.


Weedlines: A Sargassum Blog

PS-19-05 Daily Log

May 28, 2019 (Day 1)*

*Note: these will be posted on a one-day delay, i.e., this report is for yesterday’s activities.

Welcome back to Weedlines, our daily cruise blog that documents our Sargassum research activities aboard theR/V Point Sur. This will be the last cruise for our NOAA RESTORE Sargassum Project, so we hope to make the best of our time at sea. We’re glad you’re joining us for the ride, and we would like to remind you that we also post updates on the @larvalfishlabTwitter account, so follow us there as well!


The sargassum collected with the neuston net to be sorted by the science team. (Photo: Sandra Huynh)


The R/V Point Sur as the sun sets over the Port of Gulfport (Photo: Carla Culpepper)

As a reminder, the overall goals of our project are to understand the nursery role function of Sargassum habitats for the juvenile stages of numerous managed fish species, and use this information along with remote sensing estimates of Sargassum biomass to develop habitat indices for species and ecosystem assessments. Among the many commercially and recreationally important fish species we encounter are Grey Triggerfish, Tripletail, Greater Amberjack, Lesser Amberjack, and Mahi Mahi. In addition, juvenile sea turtles are often associated with floating Sargassum mats, so although sea turtles are beyond the scope of this project, the utility of our habitat indices extends beyond fishes. These are just a few of the reasons why we are so excited about this work!

Now on to today’s news.

We left the Port of Gulfport shortly after midnight. Remote sensing observations and first-hand reports indicated that Sargassum is plentiful in the northern Gulf right now, which is great news. The not so great news is that the sea conditions are not optimal. Forecasts across much of the northern Gulf call for 3-5 or 4-6 foot seas during the early part of this week, along with wind speeds ranging from 10-20 knots. For a vessel the size of the R/V Point Sur, these conditions are not a problem. However it is hard to effectively sample Sargassum habitats in these conditions. First, even moderately rough seas can break apart Sargassum weedlines and mats into smaller, scattered clumps, which are more difficult to collect with our plankton nets. Also, it is hard to visually locate Sargassum on the horizon as weedlines dip into wave troughs. Lastly, sample collection is made more difficult in moderate-to-rough seas; the neuston net comes out of the water in the wave troughs, reflectance measures are hampered by turbulent conditions, and in general it is more difficult for the vessel to maintain a position near weedlines and mats for operations like hook-and-line fishing and CTD casts. So not only do we have to consider where to Sargassum is today, we also needed to determine if we could collect samples in the first place.


Caitlin Slife gives a thumbs up so she completes her water collection. (Photo: Sandra Huynh)

This sampling compromise sent us to relatively shallow waters (<100 m depth) approximately 60 miles or so south of Dauphin Island, Alabama. After searching all morning in ‘bumpy’ seas (3 feet or so), we located an area with numerous weedlines shortly before lunch. Everyone jumped into action and the sampling began! We made our CTD cast adjacent to the weedline to collect temperature and salinity data, as well as water samples for analyses of nutrients. We then towed our neuston net through a Sargassum mat to collect algae and juvenile fishes. Much of the Sargassum appeared ‘healthy’, but unfortunately we did not collect many fishes. We did net a few amberjack and other carangid juveniles, a tripletail, and an early juvenile mahi mahi. We’re not sure why there were so few fish this time. Maybe it had something to do with the several small sharks that schooled around us all day (?). Or perhaps it was due to the relatively low salinity in this area (around 28 ppt). In any event, it took us a while to rinse and pick our way through the entire sample, and before we knew it we had to move on to our open water sampling station. We repeated our sampling ops here, collecting many larval fishes in the neuston net (including mahi mahi).


A tripletail collected with the neuston net (Photo: Sandra Huynh)

Given the rough start, the day was an overall success. We did not collect everything we wanted, but we made the best of a less than ideal situation, and got quite a bit done. For tomorrow (Day 2), our plan is to hang around the eastern Gulf, as the seas here have calmed and the forecast looks promising; as does the remote sensing images, which show high Sargassum biomass to the east of our current position.

Kudos to my science team and the crew of the Point Sur for getting this cruise off to a great start!


The science team washing down the neuston net after an open water tow (Photo: Sandra Huynh)



Weedlines: A Sargassum Research Blog

PS-18-07 Daily Log

July 16, 2018 (Day 8)*

*Note:these will be posted on a one-day delay, i.e., this report is for yesterday’s activities.

Wow, it’s hard to believe we’ve been at this for 8 days now! Below is a summary of today’s activities aboard the R/V Point Sur, another outstanding day on the water.


The camera rig in a patch of Sargassum with the R/V Point Sur in the background taken from small boat ops.

We really hit the Sargassum jackpot today. Thanks to some helpful guidance from our remote sensing team, by 0830 this morning we had located a region of the Gulf with very high Sargassum biomass, the most we’ve seen during this project by far. As we slowly approached the mats to pick a few nice sampling targets, we were greeted by large schools of fish–Triggerfishes, Filefishes, Amberjacks, other small tunas and jacks, and more. Just an amazing number of fishes, many of them adults, though there were quite a few juveniles as well. We were in the bluest of blue water, so they were easy to see, and we got to work!


The ROV being deployed as fish swim nearby.

Our sampling ops proceeded well, including the CTD cast, water sample collection, and camera rig survey. The Sabiki rig fishing was so productive we cut our fishing time in half after collecting many juvenile (small and large) Amberjack species (Seriolaspp.). We conducted an ROV survey under one of the large mats and observed scores of fishes, including Tripletails, Mahi Mahi, and numerous Filefish and Triggerfish species. Although very hot today, the sea conditions were absolutely perfect, glassy smooth, so we decided to try our luck with the purse seine. After one set that didn’t quite work out, the second purse seine set collected a large amount of Sargassum, along with Sargassumfish, Tripletail, Rainbow Runner, Filefishes, and other species. A very nice haul–thanks to a lot of effort (kudos to everyone who made that happen!). We wrapped up our sampling for the day (and for this cruise) with an open water station, where in addition to CTD data and water samples, we collected more cool fishes in the neuston net, including larval Billfish, Flyingfish and Mahi Mahi, among others.

Purse seine

And that’s it. We have set a course for Gulfport and expect to arrive at our home port around 1800 or so on Tuesday evening. This will be the last daily report for this cruise, as tomorrow will be spent cleaning our gear, packing samples and equipment, downloading vessel data, and cleaning up the lab and state rooms for the next group coming aboard. Not nearly as exciting as the previous 8 days.


I want to thank the Captain and crew of the R/V Point Surfor another wonderful cruise; we certainly could not accomplish our work without you guys. It’s been a productive and fun cruise, as always. And thanks to our funding agency, the NOAA RESTORE Act Science Program, for making this research possible.


First Mate JD Ellington, Assistant engineer/deck operations Mark McMullan, Captain Nicholas Allen, Chief Engineer Josh Jansen, Marine Technician Josh Bierbaum, Chef Alex Forsythe

And thanks to everyone who followed along with us during this cruise and our previous cruise in May. We hope you enjoyed the blog. We’ll be on the water again 2019, so don’t forget about us. Between now and then, we’ll be working up our samples, processing data, and preparing manuscripts for publication. We also plan to attend several state and federal management meetings to update fisheries biologists on our research, and work with them to incorporate our findings into population assessments for managed species.

P.S. from the Chief-Scientist

Science Team.jpg

Science Team.png

Frank.jpgI can’t express enough my gratitude to all of the young scientists aboard the R/V Point Sur during our cruises this year. They have worked tirelessly, without complaint, in summer heat and in the rain. They are diligent and serious about the work we are doing, and at the same time their good cheer and gumbo of personalities has made these trips some of the most enjoyable I’ve ever had. To go to sea on a large research vessel is, for some, a once in a lifetime experience. For this summer’s group of undergraduate interns, graduate students, research technicians, and postdocs, I sincerely hope this is not the case, and that they enjoy many such opportunities in the future, perhaps even leading their own cruises one day. Until then, you are always welcome to hop on board with me, anytime!