Category Archives: Yazaryan, Ara

Wrapping Things Up

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— Written by Ara Yazaryan

Following extensive data collection, my research has yielded some interesting results. After sorting through several sheephead stomach contents, I have discovered some interesting trends. Sheephead tend to eat a lot of urchins! Their stomachs were full of spines and tests. They also have a high affinity for bivalves and algae covered in bryozoans. It was also interesting to directly observe that smaller individuals consumed more bivalves, whereas larger sheephead ate many more and larger urchins. I am currently still processing all this data to derive conclusions and make it ready for our upcoming research symposium.

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An Anacapa Sheephead that I caught, dissected and analyzed. Its stomach was filled with mostly algae, as well as a salt-and-pepper urchin.

In the future, I think it would be interesting to continue studying the Sheephead of Anacapa. By increasing sample size and studying more individuals, the composition of this diverse kelp forest community can be assessed. Other fish species could also be studied, using their guts to further elaborate our understanding of kelp forest food webs.
Overall, this research is important for quantifying the many branches that make up the kelp forest community structure. By studying the interrelated dependence and predator-prey interactions, the fine intricacies of kelp forest community structure will be revealed. The vital role that sheephead play in this community will also be further quantified. By limiting urchins and helping control other populations of invertebrates, sheephead play a vital role in helping maintain the kelp forest. Dare I say that they may even be considered a keystone species…?

Data collection has been completed, the microscope has been shut off, and the stomach contents are finally analyzed. Unfortunately, my time here in the Caselle laboratory as a REU researcher is drawing to a close. However, this summer full of fishy adventures will be remembered forever. The interactions, experiences, and techniques I have attained here have helped to mature me both as an individual and as a scientist. Research has captured me in its grip, and tempted me with its allures. The pursuit of the wonders contained in the unknown, as bottomless as the sea is deep, motivates me to carry onwards.

 

Materials and Methods of Ara’s Fishy Project

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— Written by Ara Yazaryan

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Me and my prized catch, a nice sized male Sheephead (Semicossyphus pulcher)

My experiment, now finalized, is very exciting: I get to study what the Sheephead of Anacapa are eating! My project is a quantitative assessment of Sheephead (Semicossyphus pulcher) stomach contents across several different sites and populations at Anacapa, part of the Channel Island chain. Anacapa has a unique conservation history, as the MPAs established here are of varying ages. One site is 40+ years old, and is one of the oldest Marine Protected Areas in the state of California. Another was established relatively recently, and the remaining areas of the island remain open for public use. Across these three study sites, I seek to determine the diets of Sheephead across different ages and areas.

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A fully dissected and processed Sheephead, complete with gut contents in tray

First, Sheephead were collected from these three sites (with appropriate research licensing of course) via SCUBA spear-fisherman or – much to my angling delight – with hook-and-line. Next, the fish were dissected in lab. Various parts of the fish were saved for future study: the organs, otoliths, eyes, muscle tissue, gonads, and gills. But for my efforts, the stomach intestine was squeezed to release the slurry of partially digested fish food. These stomach contents were then weighed, placed into a Falcon Tube, and preserved in ethanol to prevent decomposition (and the horrendous smell that accompanies it). Upon preservation, I place these stomach contents into an examining tray to view under a dissecting microscope, under a snorkel vent to alleviate the less-than-stellar odour. Using a low-power scope to help me view the small pieces, I correspondingly separate the contents into categories. Based on my findings thus far, the majority of the sheephead gut contents consist of urchin spines and shell fragments, kelp encrusted in bryozoan colonies, small crabs, gastropods, and bivalves. However, a few unique finds have been unveiled: such as unidentified fish spines and scales (Sheephead

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A sample of Sheephead stomach contents under a microscope: a hermit crab, urchin spines and tests, as well as mussel shell fragments can be seen.

are not normally known to be piscivorous), octopi, pieces of gravel and sand, and even a plastic nurdle (a small bead of resin plastic such as polyethylene used in the production of larger plastic objects). Such variable stomach contents, once separated, will correspondingly be assessed to determine the composition by percent volume. Data will then be pooled from many fish from all three sites at Anacapa to determine dietary trends.

Though identifying, separating, and sorting each shell fragment may seem tedious at times, I am nonetheless driven by curiosity and the pursuit of scientific knowledge. Much like the Californian gold miners of old descending into deep, dark mines to unearth unknown treasures; I plunge my tweezers with nervous anticipation into the mushy lumps of partially digested Sheephead guts, facing constant perils and danger. Okay, maybe I am being a tad hyperbolic, but hopefully my point comes across. My stomach content examinations are part of a larger effort to understand fish populations, and the effects MPAs have on fish conservation. So I carry on with my unwavering efforts, to explore the vast unknown wilderness that is the world of fish guts!

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In the midst of gory dissection, complete with gloves, photo courtesy of Dr. Jenn Caselle

Ara’s Fishy Adventures

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— Written by Ara Yazaryan

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Counting dorsal rays of a rockfish

As a research assistant in the Caselle laboratory, my entire experience revolves around fish. My day starts at 9 o’clock, when I report to the lab and march over to the microscope for duty. One of the ongoing projects in the Caselle lab which I have the good fortune to partake in is the SMURF monitoring program at Santa Cruz island. The SMURF discussed here, contrary to the little blue people that may come to mind, is a large black “cushion” of intertwined black fencing material. SMURF stands for Standard Monitoring Unity for the Recruitment of Fishes. This large object is meant to mimic kelp structure, and gives planktonic fish larvae a place to settle and grow. Every two weeks, these SMURFs are netted and the fish are collected and frozen for later study. And this is where my abilities with a microscope come in! One of my primary laboratory responsibilities is to count and sort the SMURF fishes into each respective species. Though some species, such as Cabezon (Scorpaenichthys marmoratus) are instantly recognizable, other families of fish, such as juvenile rockfish (Sebastes) and the Clinids require a closer look. In order to separate them into the respective species, all rockfish must be observed under a dissecting microscope in order to count their fin rays. Each species of rockfish has a unique combination of dorsal and anal fin rays, serving to identify these individuals when they are young and have not yet developed their respective mature morphological features. I examine these fish one-by-one and sort them, and then place them into a final freezer storage.

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Otoliths – note the concentric ring structure

When my eyes need a break from the microscope, I move on to fish dissections. Another of my laboratory responsibilities is extracting the otoliths from fish heads. After opening the brain case, these “ear-stones” are extracted and saved for storage. Eventually, the otoliths will be polished and observed under a microscope. As a fish mature, information about what it eats, rates of growth, and potential environmental stressors is stored inside their otoliths. All this important information can be gleaned by extracting and observing the otoliths.

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Large Male Sheephead (Semicossyphus pulcher) collected at Anacapa Island

The third project that I have just begun to work with is the monitoring of California Sheephead (Semicossyphus pulcher) stomach contents between sites at Anacapa Island. Fish were captured by spear or hook-and-line (much to my inner angler’s delight) and their stomach contents will be examined to determine how MPAs affect their feeding habits and population levels. The overarching goal of these three projects, and the information I aspire most to learn about, is how California fish communities are responding to Global Change. Fishing, climate-change, Ocean warming and acidification, and pollution all have the potential to degrade our rich fish stocks. By studying and monitoring these fish, I hope to gain a better understanding of California’s complex marine ecosystems. In particular, I want to more thoroughly understand how MPAs conserve fish populations, and correspondingly alter dietary structures. I will use the Sheephead (As Dr. Caselle has made very clear, there is no “s” in the middle) as a model organism for this experimentation. I seek to answer the question: Does dietary composition of Sheephead change inside and outside of Marine Protected Areas? Using observation of stomach contents coupled with statistical quantification, I set out to answer this question over the course of my REU program. Though only two weeks have gone by, I feel as if I have gained a year’s worth of scientific immersion. Between lab work, field research, and peer camaraderie, I have gained a much clearer understanding of what research in the marine science field consists of. I look forward to what is to come, and am excited to examine many more fish in the upcoming weeks at UCSB.