By Kristin Walovich, Pacific Shark Research Center
White Sharks, Manta Rays and Tiger Sharks are easily identifiable to most, but there are more than 1,200 species of sharks, skates, rays and chimaeras, collectively called Chondrichthyans, known to science.
For my Master’s thesis I study a unique group of fish known as ghost sharks, chimaeras or ratfish. They are related to sharks and rays because of their cartilage skeleton, but look quite different. They have large pectoral fins, rabbit-like teeth and a long tapering body (check out an amazing video here). We know very little about these deep-sea creatures, in some cases something as simple as their name.
The Spotted Ratfish is a species of Ghost Shark found in California.
There are 49 species of Ghost Shark, however several additional species are known to exist, but have yet to be officially named. Under Dr. Dave Ebert, director of the Pacific Shark Research Center (PSRC), graduate students at MLML have named five new species of Ghost Shark since 2006. In fact the PSRC has described 25 new species of Chondrichthyans since its inception in efforts to help the 'Lost Sharks' of our oceans. The most recent edition, the Ninja Lanternshark was officially published last month and received quite the media buzz!
Last year fellow graduate student Paul Clerkin and I traveled to South Africa to search for new Ghost Shark species. For more than 15 years local researchers speculated two new species existed in the region, but no one had taken the time to look for them. It may seem counterintuitive, but a museum is a great place to find unknown species. If researcher or fisherman encounters an unidentified chimaera, it's often placed in the museum collection and forgotten.
We arrived at the South African Museum in Cape Town to gather morphometrics, a series of 96 measurements per animals that we use to describe and differentiate species. Together we measured 90 specimens for a total of nearly 9,000 unique measurements. Finding and measuring specimens isn’t as glorious as it sounds, the specimens are preserved in alcohol and stored in large tubs; one never knows what you might find. It’s a smelly job, but stay tuned over the next few months for several new species of Ghost Shark!
The South African Museum houses hundreds upon thousands of fish in their collection.
Able Seaman Pat Breshears of Oregon State University’s R/V Oceanus shuttles Holly Chiswell and Alex Olson out into the haze to collect sea surface microlayer samples offshore of Northern California.
The Chemical Oceanography and MPSL labs set out on their latest cruise this past summer in hopes of bolstering and expanding their search to answer the question: how is monomethylmercury (MMHg) transported into coastal marine fog? For those who missed our first post, a quick review:
MMHg is a neurotoxic form of mercury (Hg) recently discovered in marine advective fog along the central Californian Coast at trace levels, yet still 100 times higher than that of rain. Naturally, monomethylmercury is the byproduct of cellular metabolism in certain anaerobic bacteria; created (or methylated) from available elemental Hg. Oxygen minimum zones in the ocean also show increased levels of MMHg, suggesting its production occurs within microenvironments in these zones. In other words, it’s possible that bacteria that make their living in the anoxic depths of the ocean may be pumping out MMHg from any available elemental Hg in seawater. Elemental Hg (the kind found in old thermometers) is widespread and found globally in trace amounts. Volcanoes and other geologic venting were the main contributors of elemental and reactive forms of Hg to the atmosphere before the Industrial Revolution. Since then, global atmospheric levels of Hg have more than quadrupled. Anthropogenic sources of Hg are responsible for most Hg poisonings worldwide. One event, involving MMHg in waste discharge from a chemical plant, led to thousands of deaths in the small Japanese fishing town of Minamata. This event in the 1950’s, led to elevating global awareness of MMHg pollution. “Minamata’s Disease” is now a term used to describe the symptoms associated with the degradation of the body’s nervous system as a result of high MMHg toxicity. In case you are wondering, these symptoms include:
Tremors
Changes in vision
Deafness
Muscle coordination
Loss of sensation
Memory loss
Personality changes (nervous, irritable, shy)
MMHg is lipid-soluble, meaning it can enter tissue membranes and accumulate in organisms that take it up. This is how a chemical plant’s refuse contaminated Minamata’s local seafood populations, yet this process of biomagnification also occurs naturally. The EPA has suggested moderating consumption of certain fish species of higher trophic levels (upper food chain) and water-filtering organisms (mussels) for a few decades now. Increased atmospheric deposition of Hg from increased industrial activity contributes to the growing Hg levels in seawater, which could potentially expose the global population to MMHg contaminated seafood.
So how does this MMHg we normally see in anoxic (no oxygen) mud bacteria end up in the ocean and then coastal fog?
There are a few suspects in this investigation...
Plankton is prolific in the ocean, and one of the first likely steps for MMHg bioaccumulation into the food web. The genes hgcA and hgcB responsible for methylation in known methylating bacteria (typically sulfate reducing) can be compared to observed plankton species to see if they are genetically capable of producing and excreting MMHg as well. If methylating plankton are identified, then Hg enriched incubations can confirm which species are methylating in the water column, a “Who’s who in the zoo”.
MPSL Lab tech Chris Beebe eyes a colorful plankton tow.Graduate students Holly Chiswell and Kristin Walovich filter samples for an onboard methylation experiment.
The interface between air and sea is a place of biogeochemical shenanigans, where phase changes and aerosol production play a major role in the creation and cycling of organic/inorganic matter and pollutants. This sea surface microlayer (SML) is ~50-100 microns thick, and a zone where insoluble material accumulates, often concentrating trace materials and contaminants. It is from this layer that MMHg may also accumulate, and eventually be vaulted into the atmosphere by wave action, where it would then become the MMHg signal we detect in the fog.
The Chemical Oceanography Lab will be discussing their latest results with other fog researchers as part of a group called FogNet. Here they will examine their data in the context of fog dynamics along the California Coast. Check out some pictures and stay tuned!
Unofficial cruise mascot "Bear" secures the fog sampler for sea.Collecting microlayer samples attempting to capture the air-sea interface.Collecting microlayer samples attempting to capture the air-sea interface.Returning to the R/V Oceanus after microlayer sampling.Resetting the CTD in some splashy weather.Resetting the CTD in some splashy weather.MPSL director Wes Heim helps prepare labels before mustering the science crew on deck.The stern of the R/V Oceanus gets a salt rinse.Collecting fog samples shortly after escaping an offshore fog bank.Collecting fog samples shortly after escaping an offshore fog bank.
The Breakwater Beacon is an iconic landmark of the campus. It looks great lit up at night!
A big part of what makes studying marine science great is being able to travel around the world and see how different ecological systems operate. Although MLML’s location in the heart of Monterey Bay makes it ideal for studying the marine environments of California, as a student studying coral reefs, I relish the opportunity to travel abroad and see different reefs around the world. This past summer, I attended a three week summer workshop at the King Abdullah University of Science and Technology (KAUST), located along the coast of the Red Sea in the Kingdom of Saudi Arabia. In these three weeks, I was able to learn about the research being done in the university’s Red Sea Research Center, as well as spending some time exploring the coral reefs of the Red Sea and learning about the culture of Saudi Arabia.
We spent some days in the classroom learning about various faculty and student research projects, ranging from studies of microbes and genetics to the movement of whale sharks! However, we also spent some time in the field seeing the local reefs firsthand. And let me tell you, as someone with most of my experience in the Caribbean, these reefs did not disappoint! The reefs had amazingly high coral cover, and I was able to see some creatures that you can only find in the Indo-Pacific region.
Some of the reefs we saw were absolutely stunning!
A beautiful giant clam hanging out among the coral
We even got to see some clownfish (I'll spare you the "I found Nemo!" joke)
Despite seeing some amazing creatures and beautiful reefs, many of the large fish species were absent. We didn't see any large groupers or wrasses, and only one snorkeling group saw a shark. Unfortunately, many of the local reefs are fished pretty heavily, with a lot of the fish ending up at the nearby Jeddah fish market, which we got to visit towards the end of the trip. There were all kinds of fishes on display, including the large individuals missing from the reefs we visited. Some projects at KAUST involve monitoring the fish market for catch trends and even occasionally buying fish to use for genetic studies.
Although it was incredible to see the reefs and the marine life associated with the Red Sea, we had a few trips into the nearby city of Jeddah to experience the culture outside of the university's campus. One night, we went to the Al-Balad market in historic Jeddah to shop and see this famous landmark. Out of all the things in the market, I was most impressed with the spice shops. There were mountains of various spices, many of which I never knew existed, including salt that had a sulfur taste to it!
A view of the historic district from a rooftop
Overall, the workshop was a great experience. Aside from learning about cool research, spending time in the water, and the cultural excursions, it really served as a great reminder that science is an international effort. I met scientists from around the world, and I hope to collaborate with some of them in the future. It's very easy to get absorbed in what's happening along our west coast and working with local scientists, so it's good to get out and see what other scientists are doing around the world.
But for now, it's about time to get back to working on that "thesis" thing I've been hearing so much about...
Funny story: I started writing this blog post a month ago, and then was so blindsided by the fury of end-of-semester squeeze that I've only now just gotten around to finishing it. Perhaps you can empathize, and in so doing forgive me my lack of posting. But(!), I've decided to keep it as is. If anything, the benefit of time makes it a bit more complete.
It's a Thursday night around 9:30, and I have just been rudely awakened from an unintentioned nap on my couch. It's my phone buzzing, eager to alert me to the fact that a coworker is requesting a cover at my job as a baker, which runs from 2-7...in the morning. I rise from my supine position and contemplate my schedule: the day which is now drawing to a close began with the sun. I had class from nine to noon, a meeting with my lab supervisor, some lab chores, and a guest seminar in the afternoon, and then I was racing the sunset to collect data in the field for a class project. I started my analysis, putting me home around 8, but I'll need to spend the entirety of the next two days bent over a microscope to get it all done before I dash off to Sacramento for an ecological conference.
"The Thinker," as interpreted by a marine biologist.
So no, I will not be available to cover a shift for work. As I curse myself for having slept in my contacts and consider the day's last coffee, I'm reminded of what we refer to in climbing as Factor 2 fun. There's a whole spectrum and methodology to this, but the general principle is that when something isn't fun to do, but is fun to recall later, it's Factor 2. Which explains, for instance, how one of my favorite climbs I've ever done was in Smith Rock, Oregon, many hundreds of feet high (it took hours), and I wept audibly for most of it. And maybe, it's an apt description for the last three months of life at Moss Landing. For the first time, I have that inevitable thought that every single graduate student in the annals of history had tossed around: “What, in the name of all that is good in this world, have I gotten myself into?”
But before I plant the dagger entirely too far in the heart of academic pursuit, a little context, if you please. I think it's worth discussing the reasons for being so busy. Because when the days are filled up with field trips and research cruises and diving in kelp forests, you can't really complain too much. So, if the goal of my involvement in this blog is to chronicle a “day in the life,” I figured I'd take a little time to talk about my various classes. You can not only get a sense of the process, but also a little background information on the classes themselves, if you're eyeing Moss Landing as a potential graduate school.
Marine Ecology (MS 103)
We put in some early mornings on the John Martin.
This class has been all about tangible skill development, in the sense that each lab is meant to familiarize us with a particular piece of equipment, research technique, or aspect of experimental design. It's fairly hands off, in the sense that once we obtain the data for each experiment the handling of it is left largely up to us. We're expected to coordinate as a class and it's a nice contrast to our individual research projects for the course, during which we are almost entirely self-reliant. I'm working on a parasitic trematode infecting a non-native estuarine snail that we have here in Moss Landing, which plays in well to my lab's theme of invasive species.
Science!
As to the experiments themselves, we've performed chlorophyll analysis of mud samples from the harbor, we've done sampling design using quadrats and UPC (Uniform Point Contact) to monitor motile (moving) and sessile (non-moving) species abundance. We chartered the university's largest boat, the John Martin, to go out trawling and see what we could bring up (result: a lot). And we got our hands dirty dissecting all the bugs and critters out of kelp holdfasts (the "root" of kelp plants that holds it to the rock).
Geological Oceanography (MS 141)
I approached this class a bit tepidly, mostly because I didn't really see much relevance to whatever thesis I might come up with. I'm an invertebrate molecular ecologist. But, I took a marine geology class as an undergraduate and really enjoyed it, and the alternative was physical oceanography, the uttering of which causes me to break into hives.
Class fieldtrip to Pinnacles National Park.
Fortunately, I've been similarly pleased with this foray into geology. The class is interesting and engaging, our professor knowledgeable and eccentric, and I feel a certain affinity for the “fly by the seat of your pants” way this course proceeds. The syllabus is never up-to-date, but that's generally because we're trading out a lecture on igneous rocks for an overnight fieldtrip to Point Reyes. It's plastic, much like the convecting mantle churning away below our feet. I've come, in this way, to learn a lot about places I've been visiting for years. Suddenly a tidepooling excursion on West Cliff in Santa Cruz isn't just about how many crabs I can torment. It includes phrases such as “Miocene authigenic carbonate vent structures” and “biosiliceous unit.” There's an intricate relationship between the geology of a region and its associated ecosystem, and I gravitate towards the multiscopic lens that interdisciplinary approaches lend to a discerning eye.
Samples of cores taken from Elkhorn Slough.
For my class project, we went out to take sediment cores from Elkhorn Slough, a process that was entirely new and exciting for me. We managed to nab about 1,500 years of history, and what it tells us is that the slough, like any habitat, is largely dynamic through time. While human hands have altered it pretty drastically in the last century, the slough was once a lagoon, an estuary, and a nearshore environment, each with its own chemical and biological signature. In an artistic sense, I find the cores to be quite beautiful.
Marine Science Diving (MS 105)
The Scientific Dive class tests out our species ID skills at the Monterey Bay Aquarium.
A class where all you do is dive, what's not to love? This is the class you take if you want to be able to dive for research here at Moss (or beyond), as it awards you with your AAUS (American Academy of Underwater Sciences) Scientific Diver certification. Over the course of the semester it touches upon underwater sampling methodology, species identification, and general diver competence. But really, it's just a class where we talk about diving while eating and then go diving, which has been pretty spectacular. I've been diving locally for years, but through 105 I've added several new dive sites to my roster: Hopkins, Stillwater Cove, Butterfly House, Del Monte Beach, and even the kelp tank exhibit at the Monterey Bay Aquarium! Having dove around the world, I can honestly say that nothing touches my watery heart quite like a healthy kelp forest does.
The Other Stuff
Portrait of lab work, complete with Boba Fett mug.
And then there's all the other Moss Landing-centric stuff that I've gotten up to that are outside of my classes. I took a boating course to be able to drive the whalers we have available for research. I fainted during it, but we'll pretend it's due to the innate beauty of the four-stroke engine we were learning about and not the truth, which is that I'm incapable of “adulting” properly. In any case, the small boats crew has earned my eternal gratitude, and I've been continuously impressed by their approachability and skill at what they do. It's a goal of mine to get more involved in boat operation while here at Moss, and I love that they make it easy for students to get access to and experience with boats. My time on the water has been some of my favorite at Moss Landing thus far.
A nudibranch we found during a kelp holdfast dissection.
November marked the annual meeting of the Western Society of Naturalists (WSN). You can read about it HERE . I'll just add in my bit to say it was a great way to bring scientists together in a creative space. WSN is the platform from which many graduate students present their first poster or give their first talk. I'm hoping I'll be on the docket before long. Next year is the 100th anniversary of the society, being held in Monterey, and promises to be quite the affair.
Lastly, I'm working in my lab, as all students do. For someone who works in an invertebrate molecular ecology lab, I have staggeringly little experience in molecular technique. So, it's definitely been a learning exercise. Over the last three months I've been trained in DNA extraction, which along with subsequent sequencing is the bread and butter of what my lab does. It involves a lot of pipetting, which is...difficult for someone with my level of caffeine consumption. But it's been really exciting to be involved in science that is being conducted in real-time, that is tangible and meaningful.
As we speak I'm sitting in a coffee shop in Las Vegas, contemplating the upcoming year and trying to coalesce a thesis topic out of thin air. It's still a bit early to say, but all signs seem to be pointing towards my involvement with a grant we have aimed at studying biodiversity and promoting education among international scientists. I think this is a good fit for me, as I loved tutoring and think science can always benefit from an atmosphere of inclusion.
Here's to some warm-water diving in 2016.
If it all pans out as I hope it does, 2016 will start with a(nother) trip to Thailand to visit my better half, followed by a 2-week research trip down to Baja California Sur in the spring, and then a summer visit to somewhere in Southeast Asia as part of the aforementioned grant to promote proper research techniques to undergraduates. I've also been elected as Secretary of the Student Body here at Moss, am charged with running the bake sale at the open house, and applied for a job as a Program Assistant for Friends of Moss Landing Marine Lab, who helps raise necessary funding to keep the labs running. So...busy is really the only word I can summon. Stay tuned, dear readers, and we will see what is to become of me. And Happy New Years! I hope 2016 is shaping up well for everyone.
Happy Holidays to all, and what better way to share the season with some festive themed marine animals and some information about them!
Christmas Island Land Crab (Gecarcoidea natalis) Photo credit: Mountainsbeyond.org
This brightly colored land crab is found only on Christmas Island and the Cocos Island and live in the rain forests; they are diurnal despite the lower temperatures and higher humidity. During the wet season (October-December) adult crabs go an arduous migration to the beaches to spawn. There are even road signs in Christmas Island to protect the crabs from during their mating season. Here's a clip about the migration of these interesting invertebrates!
2. Christmas Feather worms (Serpulidae)
Christmas Tree Feather Worms; photo courtesy of Becky
These worms make their own tubes and are commonly found in corals and come in a variety of colors. The colorful 'tree-like' appendages are used to capture food. Any slight pressure change alerts the worm to withdraw those appendages safely into their tubes. They are a common species for aquarium users, but are a challenge to maintain.
3. Sea Angels (Gymnosomata)
While these sea angels won't be singing a chorus, they are a sight to behold. Found in the arctic seas, these translucent and gelatinous gastropods (snails and slugs) have lost their shells, and evolved their 'sticky' foot into 'wings' to swim gracefully in the water column. There are a variety of species and they are no more than a couple several inches long. Below is a clip of how these angels move around!
4. Sea Stars (Asteroidea)
Chocolate-chip sea star (Protoreaster nodosus) photo credit: Marta RubioTexeira
These (usually) five-armed echinoderms are a perfect addition for our list! However do not let its looks deceive you. Sea stars have a very effective way of eating, prying the shell opening and then sticking its whole stomach inside a bivalve (mussel, clam, scallops, or oysters) and slurping the whole organism leaving an empty shell! Here's a link of a time-lapse video of it!
5. Angelfishes (Pomacanthidae)
Juvenile emperor fish (Pomacanthus imperator) (top); adult (bottom) photo from Saltwatersmarts.com
Not to be confused with the freshwater angelfishes, marine angelfishes are found in shallow tropical waters around the world, these ornate and festive looking fishes consist of 87 different species that reside in coral reefs. Juvenile species have a color variation different than the adults. Many of these species are protogynous hermaphrodites, meaning while one male control his harems of females, if that male dies, the largest female will then become a male!
This week marked the 21st Biennial conference of the Society of Marine Mammology (SMM) . For any budding marine mammologist, this conference is a dream come true - many of the great authors and researchers that we read in class and cite regularly are HERE in San Francisco. We have the chance to make some great connections for current and future research.
Moss Landing Marine Laboratories was well represented this year, with many former and present students giving poster or oral presentations. Those that did not present were in attendance, lending support and enthusiasm.
Jackie Lindsey presenting on her sea otter habitat study
One of the unique things about the field of marine science is that it is so interdisciplinary. I was able to attend talks that discussed everything from paleontology to acoustics. I tried to spend a lot of time listening to topics that I am unfamiliar with - when else will I get to hear a complex topic explained by an expert!
Keith Hernandez - presenting on his sea lion diet study
Of course, no conference would be complete without evening events to level out our science-filled brains after a day of talks. This year was spectacular, and we only left when we could no longer stay awake.
View from the top of the hotel - LGBT mixer
Second only to all of the cool science, my favorite part of the conference was a workshop put on (in part) by our own Gitte McDonald and Alison Stimpert.
Gitte McDonald, presenting the results of her porpoise heart rate study
The workshop addressed a myriad of topics under the umbrella of work-life balance. I don't know a single graduate student (in any field) who wouldn't benefit from putting a little thought into this topic. The theme of the 21st SMM was "bridging the past towards the future", and I was proud to see MLML scientists helping to do just that.
I leave you with a picture of our fearless leader, director Jim Harvey, getting into the spirit of the conference.
Jim Harvey in his role as poster pod leader and sea lion "supporter"
Let's do it again soon - I'll see you at SMM Halifax 2017!
The Monterey Bay Aquarium recently welcomed a new Giant Sea Bass (Stereolepis gigas) to their Kelp Gardens exhibit. Unlike its name, this new addition isn't so giant - barely 4 inches long!
Giant sea bass are found along the west coast from Humboldt Bay to Baja California, Mexico and can reach up to 8 feet long. While rarely seen in the Monterey Bay, they are recovering from overfishing and are being seen more in southern California. The aquarium also has a sub-adult in the Kelp Forest tank, and two adults in their Monterey Bay Habitat exhibit. You can see more of this little one here or head to the aquarium yourself!
The Monterey Bay Aquarium is free for residents of Monterey, Santa Cruz, and San Benito Counties through Dec. 13th, so go check out the new arrivals and old favorites!
Another spectacular Western Society of Naturalists conference came and went last month. For those of you who aren’t familiar, WSN is a fun-packed, scientific society that focuses on ecology, evolution, natural history, and marine biology. This year marked the 96th annual meeting which was held in Sacramento and had the largest turnout to date! It seems the attendance at WSN grows every year and it’s really not surprising. The annual conference attracts scientists, not just from the west coast, but from all over the world. This year, there were even a few students all the way from New Zealand giving presentations. The conference is packed with like-minded individuals eager to learn and present new ideas.
The 2015 WSN logo created by Beth and Mary Lenz
This 3-day long conference incorporates a bunch of 15 minute presentations of researchers ranging from undergrads all the way to well esteemed scientists. There are also themed symposiums in the mornings and workshops in the afternoons. This year’s theme for the student symposium was ‘Critical issues and innovative approaches in marine policy along the Northeast Pacific coast’ and “Global Change Marine Ecology” for the presidential symposium.
If you're interested in attending WSN, next year’s 97th annual meeting will be right here in Monterey! 2016 marks the 100th anniversary of the society itself so it’s sure to be quite an exciting conference. Mark your calendars for November 10th-13th 2016.
The conference isn’t just all science. WSNers know how important it is to work hard and play hard so after attending all these talks, what better place to mingle and unwind with a drink or 3 than the Monterey Bay Aquarium? This year's Attitude Adjustment Hour (AAH) will be held at the Monterey Bay Aquarium. You won't want to miss it! There's also the infamous auction held every year to raise money for student travel funds. Thanks to all the participants, booze and aggressively....enthusiastic auctioneers, the 2015 auction raised over $1,500!
For those students concerned about traveling to Monterey, there are Student Travel Funds available to offset the cost of gas and lodging. There are also exciting student awards as incentive to present your ideas. Hope to see you all at next year's WSN conference!
One of the unique consequences of being a student at MLML is the opportunity to participate in research opportunities outside of the institution. Many alumni from MLML end up working at surrounding research agencies and organizations, and thus will turn to the lab to look for students to help out with various projects. For example, while being a student at MLML, I have been able to participate on consulting projects and assorted research cruises, allowing me to gain valuable research experience and insight into my future career goals.
This past month, two of our ichthyology faculty members, Drs. Richard Starr and Scott Hamilton, were contacted by alumnus William VanPeeters, who now works for the California Department of Transportation (Caltrans), to work on an exciting project involving the demolition of a portion of the old Bay Bridge.
Bay Bridge (new bridge, not being demolished), Photo credit: Ryan Fields
This past summer began like any good summer does…with a trip to my favorite taco stand. After driving south from Monterey, I had finally arrived in Los Angeles. Five hours of driving (and waking up far earlier than I would have preferred) had caused me to develop a serious hankering for some carne asada topped with onion and cilantro. Three tacos later, I was finally full and continued south to San Pedro where I made my way aboard the Miss Christi. This 45-foot boat is owned and operated by the University of Southern California (USC) and would be taking me to my home for the summer, Santa Catalina Island (often just called Catalina).
The Wrigley Marine Science Center, my home for the summer. Photo by Dr. Mia Adreani.
Two hours and 22 miles later, the Miss Christi was pulling into Big Fisherman’s Cove on the northeast end of Catalina. This cove is home to the Wrigley Marine Science Center (WMSC), an environmental research and education facility owned by USC. For the next three months, I would be working on my thesis research here.
My work this summer focused on how size-selective harvesting affects the reproductive output of sex-changing fish. Specifically, I’m interested in fish that are called protogynous hermaphrodites. This is a fancy way of saying that these fish are born female and change into males later in life. In the species that I worked with this summer, blackeye gobies (Rhinogobiops nicholsii), this sex change is largely governed by social cues. Typically, a single male will have a harem of females that he spawns with. When the male is removed, the most dominant (usually the biggest) female will change sex and become the new male.
The species that I would be working with this summer, the blackeye goby (Rhinogobiops nicholsii).
Many commercial and recreational fisheries tend to target the largest fish in a population. This is especially problematic with protogynous hermaphrodites since most of the largest individuals in a population are male. This size-selective fishing tends to skew gender ratios in favor of females in exploited populations. My research is trying to figure out at what gender ratio do males start to limit reproductive output (i.e. populations start to produce less new fish). Do we start to see this limitation when there is 1 male for every 5 females? What about 1 male for every 20 females? This is what I’m trying to figure out.
California sheephead (Semicossyphus pulcher) is a popular protogynous hermaphrodite that is the target of multiple fisheries. Size-selective harvesting has led to skewed gender ratios in some heavily exploited populations. Eventually I hope to apply the findings from my research to economically-important species like California sheephead. Photo by Monterey Bay Aquarium.
To test this, artificial reefs were constructed and fish were placed on each reef. Each reef had different gender ratios to simulate varying levels of exploitation (fish with fewer males were more “exploited”). The fish would then (in theory) lay their eggs which would then be examined for fertilized and unfertilized eggs (unfertilized eggs can be distinguished from fertilized eggs based on their cloudy, white appearance). The number of unfertilized and fertilized eggs would then be compared between the different gender ratios. The higher the proportion of unfertilized eggs, the stronger the male limitation.
Tyler Gerome swimming by one of our completed reefs! Photo by Dr. Mia Adreani.
So first things first, we had to build our reefs. A total of 20 reefs were constructed that consisted of cinder blocks and rocks. We collected our rocks from a nearby beach and dropped them (along with our cinder blocks) onto the seafloor in buckets attached to ropes. This was easily the most labor intensive part of the project but was also incredibly gratifying to see these reefs get built from nothing. Cages made out of wire mesh were placed over these reefs to prevent predators from eating our blackeye gobies. We also placed overturned terra cotta flowerpot saucers on each reef. Blackeye gobies readily lay eggs on the underside of these which would make it easy to quantify the number of fertilized and unfertilized eggs.
Tyler Gerome, Alexis Estrada, and Dr. Scott Hamilton collecting rocks that would later be used to construct our reefs. Photo by Dr. Mia Adreani.Dr. Mark Steele and graduate student Alexis Estrada constructing one of the cages that would be going over our reefs. Photo by Dr. Mia Adreani.
Once the reefs were built, we had to put fish on them! Using hand nets and SCUBA gear, we went out to local reefs to collect fish from native populations. Fortunately, blackeye gobies aren’t the brightest fish in the sea and could be easily caught by slowly placing our nets over them as they sat on the sand (they like to hangout on the interface between rocky reef and sand). For me, this was the most fun part of the whole project. By the end of the summer, I believe we had caught around 1,000 blackeye gobies. Suffice to say, I was counting blackeye gobies rather than sheep as I drifted off to sleep each night.
Erika Nava collecting gobies for our reefs! Photo by Dr. Mia Adreani.
We would then return to the lab at WMSC where the gobies were tagged using visual implant elastomer (VIE) tags. These VIE tags are a liquid that is injected underneath the skin. After injection, the liquid cures into a pliable solid that can be easily seen through transparent tissue. These tags allowed us to quickly identify the size and sex of each individual. This was important as we would regularly check up on the fish to make sure that the desired gender ratios for each reef were maintained.
Determining sex, measuring length, and tagging our gobies in the lab! Photo by Alexis Estrada.A VIE tagged blackeye goby on one of the reefs that we built. You can see the tag directly beneath the dorsal fin on the fish's "back".
Once tagged, we released our gobies onto our artificial reefs. We had 20 reefs with 20 fish on each reef. We had 10 different gender ratios (each gender ratio is a different “treatment”) which ranged from 1 male:19 females to 10 males:10 females. Each gender ratio was represented on 2 reefs (these are what we call “replicates”). Once the gobies were released on to the reefs the bulk of our work was done! All that was necessary now was to monitor the saucers for eggs and to maintain the desired gender ratios.
Unfortunately, our gobies didn’t want to cooperate with us. They weren’t laying eggs and without eggs (to compare the proportion of unfertilized eggs between different reefs) we didn’t have any data! We aren’t 100% sure why they weren’t spawning but the leading theory is that the water was too warm. There were some days that temperatures on the bottom were as warm as 70F! That’s just how things go in this field sometimes though…it doesn’t always work out.
While everything may not have gone according to plan this past summer, I still learned a bunch. While I may not have collected any data that I can use for my thesis, I learned what will and what won’t work for this project. I learned how I can streamline the project and I have no doubt that everything will run much smoother in the future. And the most important thing of all, I learned that my advisor has some wicked moves on the dance floor. I look forward to returning to Catalina Island this summer to continue my thesis research.
Erika Nava and me on the surface before one of our collection dives.
Before I sign off, I wanted to thank Dr. Mark Steele, Dr. Mia Adreani, Dr. Will White and my awesome advisor, Dr. Scott Hamilton, who were the reason this project got off the ground in the first place. My research is part of a larger NSF project that the four of them are conducting that will be taking place at Catalina over the next two years. I’d also like to thank our wonderful assistant researchers/volunteers: Alexis Estrada, Tyler Gerome, Katie Neylan, and Erika Nava. They were out there every day with us busting their butts to get this work done. And last but not least, I’d like to thank the Wrigley Marine Science Center and the wonderful people that work there. Without all of these people, none of this would have been possible. See you guys next summer!
All of the amazing people involved with this project! From left to right: Hudson (Scott's son), Dr. Scott Hamilton, Dr. Will White, Erika Nava, Sam Ginther, Alexis Estrada, Dr. Mark Steele, Katie Neylan, Tyler Gerome, Dr. Mia Adreani, and me!
Last year fellow graduate student Paul Clerkin and I traveled to South Africa to search for new Ghost Shark species. For more than 15 years local researchers speculated two new species existed in the region, but no one had taken the time to look for them. It may seem counterintuitive, but a museum is a great place to find unknown species. If researcher or fisherman encounters an unidentified chimaera, it's often placed in the museum collection and forgotten.
Some of the reefs we saw were absolutely stunning!
A beautiful giant clam hanging out among the coral
We even got to see some clownfish (I'll spare you the "I found Nemo!" joke)
A view of the historic district from a rooftop
