If you read my previous blog post, you may remember that I spent my summer out on Santa Catalina Island at the Wrigley Marine Science Center (WMSC), a research facility owned and operated by the University of Southern California (USC). While there, I began my thesis research examining the effect of male limitation on the reproductive output of blackeye gobies, a temperate sex-changing fish. While we were able to successfully set up the project, we were unable to collect any useable data.
A blackeye goby (Rhinogobiops nicholsii). My study species for this project. Source: Ron's Critter of the Day.
Undeterred, we returned to WMSC this past January in an attempt to get the project up and running again. The artificial reefs we had built and used this past summer were still in place so our first order of business was to collect some fish. To get my project going, we would need to catch approximately 500-700 blackeye gobies. Much to our dismay, we found that the number of blackeye gobies on the surrounding natural reefs was too low to continue with the project in the winter. On the first few dives at our collection sites, we didn’t see any blackeye gobies.
Dr. Mark Steele (one of the principal investigators on this project) has been working with gobies around Catalina Island for the majority of his career and had never seen abundances this low before. If you recall from my previous post, the major problem that we had with blackeye gobies this summer was that they didn’t want to spawn. We think that this may have been due to the incredibly warm water temperatures this summer. If our fish weren’t spawning, it’s very likely that the natural populations of blackeye gobies weren’t spawning as well. This may have been what caused the low numbers of blackeye gobies that we saw in January.
I will be returning to WMSC this summer in another attempt to obtain some useable data. I am confident that this field season will provide more favorable results as long as there are a sufficient number of gobies for use in this study. While it’s likely that the water temperatures will still be warm, moving the reefs deeper in the water column (to 60 feet as opposed to the 30 feet that they were at last summer) may help combat this.
I’m looking forward to spending another summer out on Catalina and can’t wait to get back in the water again!
The beautiful view from the helipad at Wrigley Marine Science Center (WMSC).
Understanding how people use the ocean and its resources is not straightforward. Some fish for a job. Some fish for fun. Some don’t fish at all and use the waters for recreation, tourism, or science. How can we manage the ocean when so many different groups (stakeholders) have different needs and wants?
Last semester, students explored these issues in the Fisheries Biology and Resource Management seminar course taught by Dr. Scott Hamilton (Ichthyology) and Dr. Rick Starr (Fisheries and Conservation Biology). We learned that many fisheries around the world are overexploited, such as the decline of Nassau Grouper in the Bahamas, Common Thresher sharks around the world, and the Brown Sea Cucumber in the Galápagos Islands.
However, not all is “doom and gloom” – success stories in fisheries management do exist. The Orange Roughy in Australia is thought to be in recovery, and some studies suggest that globally, more fisheries are recovering from overexploitation.
The class featured discussions with weekly speakers, in-depth presentations from each of us on a fishery of our choice, and even a field trip to a Pacific Fishery Management Council meeting in Sacramento. For me, the seminar speakers were the real highlight of the course. We heard from experts in stock assessment, management, fishing, and conservation working as scientists, managers, environmental lawyers, and entrepreneurs. I learned that jobs in this field are more diverse than I initially realized, and the speakers provided an excellent opportunity to think about potential career paths outside of academia.
Here’s what other students had to say:
"Since many of our speakers were past MLML students sharing their current involvement in fishery issues, this made the course feel more like a window into our career futures!"
“I thoroughly enjoyed the fisheries course at MLML. It was an extremely enriching class that gave me insight into multiple complex components of fisheries and fisheries management. As a first year fisheries student, the presentation and paper of a specific fishery was particularly helpful… and helped spark ideas for potential thesis topics.”
– Bonnie Brown, Fisheries and Conservation Biology Lab
The 2015 Fisheries Biology and Resource Management seminar class provided an excellent opportunity for us to learn of the complexities in this field, and real-world application of management principles. The course is only offered every few years, so if any future students are reading this blog post, I recommend taking it if you can!
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!
Puerto Montt is surrounded by farmland, volcanoes, and fjords, with the Andes looming the distance, making for amazing views on our flights in and out. Photo: Heather Fulton-Bennett
In early January of this year, I boarded a plane bound for Puerto Montt, Chile. It was my first time to South America and my first time crossing the equator. Though Chile is an amazing vacation destination, I was headed there for an even better purpose - research! Myself and five other MLML graduate students were fortunate to have the opportunity to take a ten-day intensive field course at the Universidad de Los Lagos in Puerto Montt. The course, Global Kelp Ecosystems, is taught every three years in partnership with MLML and the Universidad de Los Lagos. Five instructors co-teach the course, including Drs. Michael Graham and Scott Hamilton of MLML, Dr. Alejandro Bushman from the Universidad de Los Lagos, and Drs. Silvain Faugeron and Alejandro Pérez-Matus from the Pontifica Universidad Católica de Chile. In addition to MLML students, four Chilean graduate students and one French graduate student studying in Chile also took the course.
The 2015 Global Kelp Systems class in Pucatrihue, Chile.
After a day-and-a-half of travel with an unbelievable amount of luggage (including dive gear) we all arrived in Chile.
There are few times that I would willingly wake up while it is still dark outside. The day of our ichthyology field trip aboard the R/V Point Sur was one of those days. Not only would it be my first time aboard the Point Sur, it would also be my last before its retirement after 28 years of service at Moss Landing Marine Labs. Suffice to say, I was pretty excited to have this opportunity.
Regular 4 a.m. wakeup calls are brutal even for the coolest fishing survey. Once the boat is steaming towards our destination, very few things can come between me and my precious snooze time. But this morning I heard words that had me on my feet in a hurry: “Killer whales!”
Science crew and volunteer fishermen alike clamored onto the deck and pressed ourselves against the boat railings, scanning the early morning horizon as our captain maneuvered us in for a closer look. Suddenly we saw them – two black jackknives of dorsal fins appeared over the rolling swells. We spotted two small orcas (another term for killer whale), their heads surging forward through the waves. Their characteristic white eye spots stood out like warpaint in fearsome contrast against their sleek black bodies. I watched in disbelief and euphoria as their heads broke the water’s surface once, twice, and again before they disappeared from sight.
Photo by Chad King (SIMoN)
Since I wasn’t able to snap a decent photo of my own, this one is courtesy of SIMoN and the Monterey Bay Sanctuary, who generously host a marine photo library for public use.
Though orcas are found in all the world’s oceans and are not unheard of in Monterey Bay, to actually see them here is rare and really quite special. Orcas are voracious hunters – as far as their prey are concerned, they earn their nickname, “wolves of the sea,” and probably the Latin meaning of their scientific name, Orcinus orca: “from hell!” Orcas near Monterey, like the ones I saw, sometimes hunt gray whales passing through on their migration from Mexico to Alaska with their new calves (ie, easy targets).
But even their ruthless reputation just added to my enthusiasm, which somehow always gets the best of me around whales and charismatic wildlife. Cheering and clapping at the sight of my first orcas, I threw my fist in the air and shouted “Jump!,” – you know, like in Free Willy? Apparently these orcas had never seen the movie, since they missed their cue.
Still, it was a good miniflashback for me, remembering how I used to dream of being like the kid in that movie, who lived by the ocean and got to spend time with awesome marine life, lucky duck. And now I am that kid, getting to see the real deal on days like this, roaming free. Such sweet job perks even make the 4 a.m. wake-up call worth it – at least until tomorrow morning.
By Stephen Pang, Ichthyology Lab
"Since many of our speakers were past MLML students sharing their current involvement in fishery issues, this made the course feel more like a window into our career futures!"
“I thoroughly enjoyed the fisheries course at MLML. It was an extremely enriching class that gave me insight into multiple complex components of fisheries and fisheries management. As a first year fisheries student, the presentation and paper of a specific fishery was particularly helpful… and helped spark ideas for potential thesis topics.”
