Micro Plastics, or Major Problem? The Tiny Killers of Fish With The Potential to Result in Unforeseen Ecological Consequences

Oil wells spewing crude oil into the ocean, sea turtles choking on plastic bags, and industry pumping toxic emissions into the atmosphere through their smokestacks are some of the talked about environmental problems due to the fact that they are easily seen; however, some of today’s most daunting ecological issues are comprised of things that cannot be see with the naked eye. Over the last few years the topic of microplastics within the environment, especially the role that they play in aquatic ecosystems, has been of rising concern to scientists because of the potential negative consequences that arise as a result of being consumed by fish.


What are microplastics and where do they come from?

Before we begin discussing the potential ecological impacts pf microplastics, we must first define what we mean when we say “microplastics”. If when you first read the term microplastics and the thought of tiny pieces of plastic popped into your head, then you are correct! The term microplastics can be more thoroughly defined as small pieces of plastic with a length of five millimeters or less1. There are a multitude of sources in which microplastics come from but two of the major contributors to microplastics in the environment are the natural degradation of larger pieces of plastic into smaller pieces of plastic due to exposure of solar radiation, and from the addition of microbeads to personal hygiene products2. The addition of microbeads, which are tiny pieces of polyethylene plastic used for exfoliation, to personal care products has been a practice for over fifty years until they were banned in 2015 under the Obama administration1. Research into the ecological effects of microplastics is a relatively new field of study which comes as a result of the ever-increasing input of plastic wastes into the oceans however, studies have shown that microplastics have the potential to wreak havoc on fish populations.


How are microplastics affecting fish all around the world

Since the topic of microplastics is still considered an emerging field of study, many of the effects of the microplastics on fish health are still unknown. Although this is still a relatively new field of study, several lab studies have shown a link between the ingestion of microplastics with stunted growth rates, reduced appetites, and the potential for reduced reproduction rates3. These studies have also shown a correlation between the ingestion of microplastics by larval fish and an increased mortality rate among those fish as a result of the plastic getting stuck and blocking the fish’s digestive tract3. Another study has shown that microplastics can not only affect fish populations by direct consumption, but microplastics can also decrease the population of fish food sources which ultimately can cause a shift in the population density of the fish species. This study showed that when Daphnia magna, a freshwater planktonic crustacean, are exposed to microplastics that their growth rates and reproduction rates are reduced and that these reductions are passed to the next generation which can significantly reduce their populations4. These studies have shown that microplastics can have both direct and indirect negative effects on fish populations.


Photo 1: A rainbow runner that consumed 18 plastic pieces

From Fish to Humans, A Microplastic Invasion May Be Taking a Toll

Credit: Dr. Marcus Eriksen Gyres Institute



Why you should care

Now, you may be thinking “I don’t even like fishing” or “I don’t eat fish so why should I care” so here are a few reasons as to why you should care about this emerging problem. Fish provide food for approximately three billion people worldwide, and with the potential of microplastics causing a reduction in the populations of many fish species world wide some areas may be subject to decreased food storages. Commercial and recreational fishing is a multi-billion-dollar industry within the US which provides a stable economic environment for many areas, so we as a nation need to try to minimize the negative effects of microplastics on aquatic ecosystems in order to maintain a stable economic well-being in those areas. We also need to realize that even if you don’t eat fish, some of your food sources may consume fish which allows for the microplastics found within fish to be consumed by you indirectly through the bioaccumulation, the process where contaminants move up the food web by consuming prey items containing the contaminants, of the microplastics5.


What can I do to help?

The major driving force which can reduce the impacts of microplastics on fish populations is to help prevent additional plastic from being introduced into the environment and to reduce the current amount of plastic already out in the environment. Every individual can make an impact to prevent an increase in the amount of microplastics in the environment by doing any of the following6.

  • Reduce the amount of single-use plastics you use on a daily basis. By using reusable products, you can decrease the amount of trash that you produce which reduces the likeliness of your trash being introduced into the environment.
  • Support cleanup efforts. By cleaning up litter before it reaches the ocean and other waterways, you are preventing the larger plastic items from degrading into the microplastics size categorization.
  • Inform others about the potential harmful effects of microplastics. Education is key to making your efforts a success. By educating others, they will realize the importance of the issue and will likely spread the word to others.
  • Lobby for bans on single use plastics and support organizations which strive to eliminate plastic pollution. Preventing the manufacturing of single use plastics can dramatically reduce the amount of plastic that ends up in the environment. It is much easier to prevent the problem than it is to try to clean up the problem.





1.) (2018, June). What are microplastics?. Retrieved from https://oceanservice.noaa.gov/facts/microplastics.html

2.) (N.d.) What Are Microplastics?. Retrieved from https://www.greenmatters.com/t/microplastics

3.) Parker, L. (N.d.) Baby fish have started eating plastic. We haven’t yet seen the consequences. Retrieved from https://www.nationalgeographic.com/magazine/2019/05/microplastics-impact-on-fish-shown-in-pictures/

4.) Martins, A., and Guilhermino, L. (2018, August). Transgenerational effect and recovery of microplastics exposure in model populations of the freshwater cladoceran Daohnia magna Straus. Retrieved from https://www.sciencedirect.com/science/article/pii/S0048969718308088

5.) Thompson, A. (2018, September). From Fish to Humans, A Microplastic Invasion May Be Taking a Toll. Retrieved from https://www.scientificamerican.com/article/from-fish-to-humans-a-microplastic-invasion-may-be-taking-a-toll/

6.) Hutchinson, B. (N.d.). 7 Ways To Reduce Ocean Plastic Pollution Today. Retrieved from https://www.oceanicsociety.org/blog/1720/7-ways-to-reduce-ocean-plastic-pollution-today



Image Source

1.) Thompson, A. (2018, September). From Fish to Humans, A Microplastic Invasion May Be Taking a Toll. Retrieved from https://www.scientificamerican.com/article/from-fish-to-humans-a-microplastic-invasion-may-be-taking-a-toll/


Is Everything a Bluegill?

Brooke Tracy, Ohio State University, College of Food, Agriculture, and Environmental Sciences. September 25th, 2019

To the untrained eye, it is very tempting to call any small fish a Bluegill, especially in Ohio. As a kid, I went fishing with my dad and I was just excited to catch a fish, I didn’t really care what it was. My dad would call it a Bluegill or a bass and we’d take a picture and toss it back to its happy little fishy pond. Now, I am majoring in Forestry, Fisheries, and Wildlife at Ohio State University, and identifying fish has become an interest of mine. I want to provide some tips on how to tell the difference between a Bluegill and some of Ohio’s other sunfish for those of you who are less familiar with fish ID.

Figure 1: Bluegill

Figure 1 is a photo of a Bluegill. There are a few key things to look for when identifying a Bluegill. 1.) The dorsal fin, which is the fin on the top of the fish, starts out spiny. Be careful, those spines are the easiest way to get pricked when you’re taking one of these fish off a hook. 2.) The second half of the dorsal fin is made up of soft rays, with no spines. 3.) The body of a Bluegill has vertical blueish stripes, and depending on the fish, these can be more or less obvious. 4.) And finally, the Bluegill has blue gills, which are located under the ear and behind the mouth of the fish. Additionally, the Bluegill is usually between 6-10 inches long. Seems easy enough, right? Let’s look at another sunfish.

Figure 2: Green Sunfish

Figure 2 is a photo of a Green Sunfish. Notice any differences between the Green and the Bluegill? They have the same body shape overall, with slightly different tails. The Green Sunfish has a more rounded caudal fin, which is just the name for the tail fin. Also note that the body color is much more green than that of the Bluegill, and the vertical lines on the body are much less noticeable. The gills on the Green Sunfish don’t stand out, but they have beautiful blue streaking (striations) on their face. Compared to the Bluegill, the Green Sunfish are generally much smaller, usually between 3-7 inches long.

Figure 3: Orange Spotted Sunfish

Figure 3 is a photo of an Orange Spotted Sunfish. Aren’t they pretty? The Orangspot has the same “sunfish shaped body” as the Bluegill and the Green, but this one has beautiful orange fins and a silvery blue body. They also have Orange spots on their cheeks and body. This fish is even smaller than the Green Sunfish, usually being only 2 or 3 inches long.

Why Bother?

Fish identification is important when you’re out there fishing on your own because some species are threatened or endangered. When species are in danger of extinction, regulations are put in place that limits what you’re allowed to catch, that way the fish populations that are in danger have a chance to recover without being in danger of humans. If you mistakenly take the wrong fish you could worsen their state of concern as well as receive a monetary fine. Make sure you know what you’re catching!

Your Turn!

Below are a few unlabeled pictures for you to try to identify on your own. Pay attention to the tail shape as well as the body and face markings. Good luck!















*You can find the answers under the sources and photo credits. Happy fishing!


Wildlife, Ohio DNR Division of. “Ohio.gov / Search.” Ohio DNR Division of Wildlife, wildlife.ohiodnr.gov/species-and-habitats/species-guide-index/fish/bluegill-sunfish.      (Figure 1 was obtained from this source)

Wildlife, Ohio DNR Division of. “Ohio.gov / Search.” Ohio DNR Division of Wildlife, wildlife.ohiodnr.gov/species-and-habitats/species-guide-index/fish/green-sunfish.      (Figure 2 was obtained from this source)

Wildlife, Ohio DNR Division of. “Ohio.gov / Search.” Ohio DNR Division of Wildlife, wildlife.ohiodnr.gov/species-and-habitats/species-guide-index/fish/orangespotted-sunfish.     (Figure 3 was obtained from this source)

Photo Credit

  1. Photo © Steve Harwood/Flickr
  2. https://alchetron.com/Orangespotted-sunfish#-
  3. Photo credit: J.D. Wilson, https://www.flickr.com/photos/57809070@N03/
  4. Photo by Nate Tessler, http://vtichthyology.blogspot.com/2016/09/green-sunfish-is-one-tough-sparring.html


  1. Bluegill
  2. Orange Spotted Sunfish
  3. Trick Question! This is a Bluegill-Green Sunfish Hybrid, which means the two species intermixed. That’s why it resembles both a Bluegill and a Green Sunfish. Good job if that one was tough!
  4. Green Sunfish


Are Fish Friends, or Are Fish Food?

Are Fish Friends, or Are Fish Food? 

Having a sustainable diet and knowing where your food comes from is one way to contribute to combatting climate change and preserving ecosystems. Eating fish can contribute to a healthy diet, can be culturally significant, and is more sustainable than eating other meats such as beef. However, it is important to consume fish in a way that protects these resources for now and the future. Below is a (solo) podcast that talks about these issues including sustainable fishing and fish as part of our population’s diets. 


As mentioned in the podcast, there are many ways to avoid these dilemmas. Below are a few helpful links to get you started on your sustainable fish-eating journey:

Sustainable Fish Harvesting Labeling Organizations:

Marine Stewardship Council- https://www.msc.org/

Aquaculture Stewardship Council- https://www.asc-aqua.org/about-us/about-the-asc/

Best Aquaculture Practices-https://www.bapcertification.org/

Seafood Watch lists and describes species of fish that are more sustainable to eat depending on where you are from: https://www.seafoodwatch.org/

Ohio Division of Natural Resources Fishing Licenses:




Kituyi, M. & Thomson, P. “90% of fish stocks are used up – fisheries subsidies must stop emptying the ocean”. World Economic Forum. July 2018. Retrieved from: https://www.weforum.org/agenda/2018/07/fish-stocks-are-used-up-fisheries-subsidies-must-stop/ on 22 September 2019.

Leal, D. R. “Community-Run Fisheries: Avoiding the “Tragedy of the Commons” 1998. 19 (3), 225-245.

McDermott, A. “ Eating seafood can reduce your carbon footprint, but some fish are better than others” Oceana. February 2018. Retrieved from: https://oceana.org/blog/eating-seafood-can-reduce-your-carbon-footprint-some-fish-are-better-others on 22 September 2019.

Stehfest ,E., Bouwman, L., Vurren, D. P., Elzen, M. G. J., Eikhout, B., & Kabat P. 2008. “Climate Benefits of changing diet”. Springer. 95 (1-2), 83-102. 

When Water Management Pays Off: A Win for Fish in the Ohio River

Government agencies and NGOs pour money into the management of waterways every year.  The Ohio Department of Natural Resources (ODNR) alone has four ongoing watershed restoration projects, including Riparian Corridor Protection, Channel Restoration, Alternate Cattle Water Sources, and Dam Removal.  While these projects are numerous, the results of restoration and management are often hard to immediately see.  However, a new study led by Dr. Mark Pyron, a researcher at Ball State University, sheds light on how the management of the Ohio River Basin has led to benefits for fish populations.

The Ohio River Basin, shown below in Figure 1, has been altered dramatically by agricultural use and urban development over the last two centuries.  Prior to the passage of the Clean Water Act in 1972, restrictions on what could be dumped into the waterway were few and far between.  Pollution levels were high in the river basin and negatively impacted aquatic habitat for fishes. Today, the water quality in the Ohio River Basin is improving.  Discharges into the Ohio River from direct sources, also known as point sources, are heavily regulated by agencies such as the EPA.  The Ohio River Valley Sanitation Commission (ORSANCO) is another agency committed to improving the water quality and aquatic habitat in the Ohio River Basin.  One way ORSANCO does this is through the long-term monitoring of fish populations in the river.  Yearly monitoring allows scientists and management officials to see how conservation initiatives, like the Clean Water Act or ODNR restoration projects, are paying off for fish.

Figure 1: Ohio River Basin (Pyron et al 2019)

Using 57 years of fish population data from ORSANCO, Dr. Pyron and colleagues investigated how the composition of fish in the Ohio River Basin has changed over the last half century.  Their study, entitled “Long-term fish assemblages of the Ohio River: Altered trophic and life history strategies with hydrologic alterations and land use modifications”, found that there have been significant changes in Ohio River fish populations over the last 50 years.  More specifically, there has been an increase in the species richness, or number of species present, with year.  In the study, 135 species of fish across 19 families were identified, with the most common species being the Gizzard Shad (Dorosoma cepedianum), Emerald Shiner (Notropis atherinoides), Freshwater Drum (Aplodinotus grunniens), Channel Shiner (Notropis wickliffi), Channel Catfish (Ictalurus punctatus), Threadfin Shad (Dorosoma petenense), Skipjack Herring (Alosa chrysochloris), Common Carp, Bluegill (Lepomis macrochirus), and White Bass (Morone chrysops) (Pyron et al 2019).

Emerald Shiner. Photo by ODNR (http://wildlife.ohiodnr.gov/species-and-habitats/species-guide-index/fish/emerald-shiner).

Researchers think that the increase in the number of fish species present in the Ohio River could be evidence that the management of the basin for improved water quality is working.  As agriculture around the Ohio River Basin has decreased and forests have increased, runoff into the river has also decreased and led to less turbid, or clearer, waters.  Less turbid water allows for better predation in fish that use vision to catch their prey, and forests increase the presence of insects, which are commonly consumed by fish.  The availability of new resources allows more fish to be present in the river.

Ohio River Basin. Photo by ORSANCO (http://www.orsanco.org/)

While results from the study have shown an overall increase in the number of fish species present, they have also shown that human alterations to the Ohio River waterway have impacted the types of fish species present.  More piscivores, or fish that eat other fish, were found in the river each year.  This could be due to the presence of dams that slow the flow of water and create lake-like conditions where piscivores normally thrive.

Overall, the study conducted by Dr. Pyron and his colleagues emphasizes that the management of the Ohio River Basin has been beneficial to fish conservation.  However, as the climate continues to change and humans continue to impact waterways, it is necessary to conduct further investigations into how humans can influence fish populations and conserve their habitat into the future.


  1. About Us. ORSANCO. Online. Retrieved September 24, 2019 from http://www.orsanco.org/
  2. Aquatic Stewardship. ODNR. Online. Retrieved September 24th, 2019 from http://wildlife.ohiodnr.gov/species-and-habitats/aquatic-stewardship
  3. Pyron, M., Mims, M. C., Minder, M. M., Shields, R. C., Chodkowski, N., and Arts, C. C. 2019. Long-term fish assemblages of the Ohio River: Altered trophic and life history strategies with hydrologic alterations and land use modifications. PLOS ONE 14(6):e0218915. Retrieved September 24, 2019 from https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0211848
  4. Summary of the Clean Water Act. EPA. Online. Retrieved September 24, 2019 from https://www.epa.gov/laws-regulations/summary-clean-water-act
  5. Van Velzer, R. 2019, May 7. Fish Diversity Making a Comeback in The Ohio River. WFPL. Online. Retrieved September 24, 2019 from https://wfpl.org/fish-diversity-making-a-comeback-in-the-ohio-river/

Invasive Round Goby Impact in Lake Erie

In addition to the ongoing problem of algae blooms, for years Lake Erie has been impacted by the invasive Round Goby (Neogobius melanostomus) (Bunnell et al., 2005). Having been introduced in the early to mid-90’s as a result of ship ballast water, the invasive Round Goby has had both positive and negative impacts on the Lake Erie ecosystem (State of Michigan) because of a complex relationship with native and other invasive species. Being able to change its diet based on available food sources, as well as being competitive, makes Round Goby a successful invader to the Lake Erie ecosystem (Sea Grant).

Retrieved from: http://www.seagrant.umn.edu/ais/gobies_invade

The primary food source of Round Goby in Lake Erie has been Zebra Mussels (Dreissena polymorpha), since their introduction (Bunnell et al., 2005). Zebra Mussels have contributed to the success of Round Goby in Lake Erie, being an abundant food source, and invasive Round Goby have helped in preying on this invasive mussel species. Even though Round Goby prey upon Zebra Mussels, this alone does not help with removing the population of invasive Zebra Mussels, which negatively impacts the phytoplankton (Sea Grant). With Round Goby successfully surviving off of Zebra Mussels, Round Goby themselves have been a food source for native fish species such as Smallmouth Bass (Micropterus dolomieu) (Bunnell et al., 2005), walleye, and trout (Sea Grant). Many times when people think of invasive species they only see them as destroying the native ecosystem, but the invasive Round Goby has also positively impacted the Lake Erie ecosystem in a way that some native species have been declared to no longer be endangered, such as the Lake Erie Water Snake (Nerodia sipedon insularum) (Bunnell et al., 2005).

Retrieved from: http://www.seagrant.umn.edu/ais/zebramussels_threaten

While the invasive Round Goby is thriving in Lake Erie because of abundant food source of Zebra Mussels, they also compete with native fish species for prey and use native fish as another food source. One case in which Round Goby are negatively impacting native fish species is that they compete with native fish, such as Sculpins (Sea Grant), darters and logperch (Bunnell et al, 2005) which has a negative impact on native fish populations. Round Goby have also been found to use small native fish as a food source, in addition to Zebra Mussels, such as sculpins, darters, and logperch in which they also compete with for food (Sea Grant).

Invasive Round Goby have been successful in negatively impacting the Lake Erie ecosystem and native fish populations, and because of this successful establishment, there has been little to no success in removing Round Goby.  One way to manage invasive Round Goby is to make sure that they do not spread to new watershed ecosystems, where methods such as electrical and chemical barriers may be used (Bunnell et al, 2005). There is also importance in preventing the spread of other invasive species by having regulations on ballast water in waterways, so that non-native species do not get dumped into an ecosystem, potentially to become an invasive species population (Sea Grant).

Since the introduction of the invasive Round Goby into Lake Erie, both native species and non-native fish species have both been positively and negatively impacted as a result of complex relationships. Round Goby have been successful in the Lake Erie ecosystem because of readily available food sources of invasive Zebra Mussels and native fish populations, reducing populations of native fish species. Careful considerations need to be made in following regulations on dumping ballast water in watersheds as well as human stocking introductions of species in order to prevent non-native species from establishing and reducing native species.


Bunnell, David B, et al. “Canadian Journal of Fisheries and Aquatic Sciences.” Canadian Journal of Fisheries and Aquatic Sciences – 62(1):15 – PDF, 2005, https://www.nrcresearchpress.com/doi/pdf/10.1139/f04-172.

Lydersen, Kari. “The Round Goby, an Uninvited Resident of the Great Lakes, Is Doing Some Good.” The New York Times, The New York Times, 27 May 2011, https://www.nytimes.com/2011/05/27/us/27cncgoby.html.

Mychek-Londer, Justin G, et al. “Ecological Impacts Of Invasive Round Goby (Neogobius Melanostomus) In The Laurentian Great Lakes And Beyond: Summary Of Presentations At IAGLR 2014.” Lake Scientist, 19 Nov. 2014, https://www.lakescientist.com/ecological-impacts-invasive-round-goby-neogobius-melanostomus-laurentian-great-lakes-beyond-summary-presentations-iaglr-2014/.

Ray, William J., and Lynda D. Corkum. “Predation of Zebra Mussels by Round Gobies, Neogobius Melanostomus.” SpringerLink, Kluwer Academic Publishers, Nov. 1997, https://link.springer.com/article/10.1023/A:1007379220052.

“Round Gobies Invade North America.” Minnesota Sea Grant, http://www.seagrant.umn.edu/ais/gobies_invade.

“Status and Strategy for Round Goby Management.” State of Michigan , https://www.michigan.gov/documents/deq/wrd-ais-neogobius-melanostomus_499884_7.pdf.

What Are the Current Pressures Impacting Lake Erie. 2005, https://archive.epa.gov/solec/web/pdf/erie.pdf.

“Zebra Mussels Threaten Inland Waters: Minnesota Sea Grant.” Zebra Mussels Threaten Inland Waters | Minnesota Sea Grant, http://www.seagrant.umn.edu/ais/zebramussels_threaten.

Seafood Fraud: Catfished by your Date, and then your Dinner

You’ve heard about the bait and switch in your dating apps, but have you considered it at your favorite seafood restaurant?

Photo courtesy of Boston Magazine.

Fish and other seafood are major sources of nutrition for much of the world’s population. The United States is behind China as the second largest consumer of seafood worldwide. More than 90% of the seafood consumed by the United States is imported (3), and just 2% of it is inspected annually (2). Oceana conducted a major study in 2013 using DNA analyses to examine the accuracy of seafood labeling in various markets. The study collected samples from a range of grocery stores and restaurants across the country in 21 different states. This study found that of the 1,215 samples analyzed, 33% were mislabeled (4). The study relaunched in 2018 to determine whether the issue still persists and found that it does – with 21% of the 449 samples mislabeled(5). While the rate has decreased, the issue is proven to still be prevalent.

Chart courtesy of Oceana.

Red Snapper had one of the highest rates of mislabeling of all the fish species examined at 87% mislabeling. Of all the specimens labeled as Red Snapper examined, 28 different species of fish were identified during the DNA analysis. Seventeen of which didn’t even fall into the snapper family (4).

Chart courtesy of Oceana.

Overall, restaurants were found to have higher rates of mislabeling at 38%, than grocery stores at 18%. Sushi venues in particular had a mislabeling rate at a staggering 74% (4). Another 2017 study by UCLA looked at mislabeling in sushi restaurants in Los Angeles and found that 77% of Red Snapper, Halibut, Yellowfin tuna and yellowtail were mislabeled; and every restaurant examined had at least one instance of mislabeling (6).

Mislabeling of fish can result in many ecological, economic and human health consequences. Some fish were labeled as an entirely different species, which is especially problematic when an endangered or illegally caught fish is being advertised as one that is more sustainable. This can contribute to population loss of certain species and can have major ecosystem ramifications.The supply chain for the fishing industry is complex, and it is widely unknown at which point in this chain the fraud is occurring (6). A study by the world economic forum found that 30% of fish caught globally are caught illegally, which can result in a $10-$23.5 billion economic loss (1).

Consumers are not only unable to make informed and accurate choices in their fish consumption – their health could be harmed as well. People may think they’re ordering a wild caught fish when they actually receive a farmed fish, sometimes from regions like Asia with less stringent chemical regulations for farm-raised fish (3). Some fish are advised to be avoided by certain groups due to their high mercury levels. Consuming fish with high mercury levels can be dangerous for health, especially for groups like young children or pregnant women. This was exemplified in the substitution of high mercury fish like tilefish for snapper (4).

While there are regulations and systems in place like the Seafood Import Monitoring Program to monitor the harvest and sale of fish, they are not always effective. Illegal fishing and overfishing are great threats to the marine environment. Inaccurate labeling by sellers of seafood can have many consequences. Next time you order Red Snapper, you may want to ask, is it really Red Snapper?



  1. Brett, A., & Lee, V. (2019). Ending Illegal Fishing: Data Policy and the Port State Measures Agreement. World Economic Forum.
  2. GAO. (2009). Seafood Fraud: FDA Program Changes and Better Collaboration among Key Federal Agencies Could Improve Detection and Prevention. United States Government Accountability Office. GAO-09-258
  3. Gibbens, S. (2019, March). What is seafood fraud? Dangerous—and running rampant, report finds. National Geographic.
  4. Warner, K., Timme, W., Lowell, B., & Hirshfield, M. (2013). Oceana Study Reveals Seafood Fraud Nationwide. Oceana.
  5. Warner, K., Roberts, W., Mustain, P., Lowell, B., & Swain, M. (2019). Casting a Wider Net: More Action Needed to Stop Seafood Fraud in the United States. Oceana.
  6. Willette, D. A. (2017). Using DNA barcoding to track seafood mislabeling in Los Angeles restaurants. Conservation Biology, 31(5).

Return of the Darters

The Longhead Darter (scientific name, Percina macrocephala) had not been found in Ohio since 1939. Now, in the upper Muskingum River system, that’s changed.

A team of researchers from the Stream and River Ecology (STRIVE) Lab at The Ohio State University has been working since 2016 to reintroduce fish like the Longhead Darter to rivers where they were historically, but are not currently, found. They do this through the process of translocation – finding an abundant source population of the species and moving a large group of those individuals to the desired location.1

Andrew Nagy, a research assistant for STRIVE lab, has been working on the fish translocation project since early 2018. He says that the lab has chosen to focus on state-listed fish species – those identified as threatened, endangered, or extirpated (locally extinct) – including the Longhead Darter and Tippecanoe Darter (Etheostoma tippecanoe), as well as other species that are particularly sensitive to water quality, like the Bluebreast Darter (Etheostoma camurum). Fish of these species may have struggled to survive the intensive pollution that was historically pervasive in Ohio rivers.


Tippecanoe Darter (Etheostoma tippecanoe). Image from Ohio Department of Natural Resources.


In many ways, Ohio was the birthplace of federal regulation on water pollution in the U.S., largely encompassed by the Clean Water Act. Through much of the 19th and 20th centuries, industrial pollution severely damaged aquatic ecosystems across the nation; by the 1950s and 1960s, there were no fish to be found in the section of the Cuyahoga River between Akron and Cleveland.­­2 In 1969, a pollution-induced fire on the Cuyahoga (one of many over the previous century) gained national attention and finally galvanized the public into action to improve water quality across the U.S. As a result, in 1972, extensive amendments made to the Federal Water Pollution Control Act of 1948 made it recognizable as the Clean Water Act we know today.3 With more rigorous regulation on dumping pollutants and widespread cleanup efforts, streams, rivers, lakes, wetlands, and coastal waters slowly became healthier and more hospitable to fish and other organisms that had once inhabited them. That wasn’t the end of the story, though. Even with the water quality improving to a state that could theoretically sustain them, fish were blocked from parts of their geographic range by anthropogenic barriers like dams.1 The habitat was there, but the fish weren’t.


A low head dam on Muskingum River. Dams like this one can keep fish from returning to parts of their historical geographic range. Photo by littlesis43756 / Creative Commons.

That’s where the research group comes in, intervening to restore ecosystems that have lost some of their key players. “Although keeping the environment in good condition via general things like reducing pollution and limiting human alteration is important,” says Nagy, “it is often not enough.  In many cases, we need to take specific action to repair damage that we’ve already done.” For three years in a row, the team has attempted to do just that, translocating Bluebreast Darters from large populations in the Muskingum River system to various locations in the Licking River System.1 They have also begun the same process with the Tippecanoe and Longhead Darters, says Nagy, moving fish from the Scioto River and even the Allegheny River in Pennsylvania to the Muskingum River.

The hope is that the reintroduced populations will eventually be self-sustaining, reproducing and expanding their range without ongoing intervention. Nagy says things look promising. During follow-up surveys at release sites, the team found evidence of natural reproduction in both Bluebreast and Tippecanoe Darters. As for the Longhead Darters, while there are still no signs of reproduction, fish have at least survived through the full breeding season.

No one can say for sure whether the project will reach its ultimate goal. For now, though, the team presses on with translocations and surveys, enjoying the work in various forms. For Nagy, a streamside snack of native pawpaws from a nearby grove makes the successes all the sweeter. “Few things are as satisfying for me as sitting next to a river on a cool fall afternoon, enjoying fresh fruit directly after a successful survey of a fish that I helped reintroduce.”



  1. OSU Stream and River Ecology (STRIVE) Lab. (2018). Rare Fish Reintroduction via Translocation. Retrieved from https://u.osu.edu/strive/field-photos/darter-reintroduction/.
  2. U.S. Environmental Protection Agency (USEPA). (2019, April 1). Introduction to the Clean Water Act. Retrieved from https://cfpub.epa.gov/watertrain/moduleFrame.cfm?parent_object_id=2569.
  3. U.S. Environmental Protection Agency (USEPA). (2017, August 8). History of the Clean Water Act. Retrieved from https://www.epa.gov/laws-regulations/history-clean-water-act.

It’s a bird! It’s a plane! No, it’s a Carp!

‘Asian carp’ is an umbrella term for four invasive species of carp native to Asia that include bighead, grass, bullhead and silver carp. Asian carp were brought to the States as a way for farm ponds, sewage lagoons and aquaculture facilities to control for algae, parasites and aquatic macrophytes (Baerwaldt et al, n.d.). They established themselves in the Mississippi river system after flood events and are rapidly making their way to the Great Lakes.

Map of Asian Carp distribution around the Mississippi and Ohio River Basin. Image courtesy of the ACRCC  Asian Carp Action Plan for Fiscal Year 2018

The Great Lakes fisheries can be valued up to $7 billion dollars annually and Silver carp threaten that market (Golowenski, 2019). Silver carp are filter feeders that can consume 5-20% of their body weight regularly, making them a formidable adversary against native species in the fight for food, and the cumulative feeding habits of Asian carp could reduce the turbidity that native fish depend on (Baerwaldt et al, n.d.). Adult Silver carp do not have predators in the Mississippi river system, and because this species reaches adulthood quite rapidly their window of vulnerability is quite low (ACRCC, n.d.).

Silver carp (Hypophthalmichthys molitrix ) are a particular interest of mine because of their tendency to jump out of the water when startled by boat motors. Weighing up to 20 pounds and with the ability to jump 9-10 feet out of the water, they are a hazard to the safety of recreational boaters.

Silver carp jump in the Fox River after being startled by boat motors. Image courtesy of the Asian Carp Regional Coordinating Committee, 2016.

Some ways carp are being managed by the Asian Carp Regional Coordinating Committee (ACRCC) is through electric barriers, contract fishing, and a new development of sound technology. A study by the University of Minnesota demonstrated that Asian carp have been deterred from barriers when low frequency noises were emitted, while native fish species are not known to be affected (Pennekamp, 2017).  These methods alone would not prevent the introduction of Silver carp to the Great Lakes, but in conjunction may be enough. Personally, my favorite method of Silver carp control comes from the town of Bath, Illinois. Since 2005 the tiny town has been home to the annual Original Redneck Fishing Tournament. Equipped with dip nets and sometimes football padding, boaters take to the water in droves and try to snag the flying fish out of the air. Silver carp are a schooling species so the boaters will drive close together to ensure the fish start leaping. There are 4 heats and contestants have up to two hours to fill their boat with as many fish as they can grab. There is a prize of $1000 for the team that catches the most fish and past tournaments have been able to remove over 1500 Silver carp out of the river in the span of two day. Silver carp are edible and considered delicacies in some Asian communities but are not commonly consumed by Americans. If this was implemented in Ohio, a cookout contest could be used in conjunction with the tournament to introduce Silver carp into the midwestern diet. Obviously, this method of control would not work alone but it is a way to increase awareness, raise funds, and decrease the population.


Asian Carp Regional Coordinating Committee. (2018). Asian Carp Action Plan for Fiscal Year 2018 (pp. 1276).

Baerwaldt, K., Credico, J., Kromrey, R., & Monroe, E. (n.d.). Asian Carp eDNA Monitoring. U.S. Fish and Wildlife Service

Golowenski, D. (2019, September 8). Outdoors: Asian carp threat remains for Great Lakes. Retrieved from https://www.dispatch.com/sports/20190907/outdoors–asian-carp-threat-remains-for-great-lakes

National Geographic, Redneck Fishing Tournament. (2010). Retrieved from https://www.youtube.com/watch?v=0bZ_9B_RlGY

Pennekamp, T. (2017, November 13). Broadcasting underwater noise may be a sound solution for repelling Asian carp on Mississippi River. Retrieved from https://www.guttenbergpress.com/articles/2017/11/13/broadcasting-underwater-noise-may-be-sound-solution-repelling-asian-carp

Muskellunge Recovery in Ohio

The great and powerful muskie

The muskellunge (Esox masquinongy), also known as muskie, is a large predatory freshwater fish that is native to Ohio. Mature fish weigh from 7 to over 30 pounds and have an average length of 29 to 43 inches. They are a member of the pike family (Esocidae), and have a green, yellow, and brown coloration with dark stripes. A key distinguishing feature that sets them apart from other members of the pike family is that only half of their cheek has scales. (2,3)

Muskellunge (Encyclopædia Britannica, Photo credit Doug Stamm)

Muskies are long and narrow, shaped somewhat like a torpedo. This shape allows them to move quickly through the water to chase down prey. With this large, powerful form, they can put up a good fight when caught, making them a highly coveted fish by anglers for the challenge they offer. For instance, the largest recorded muskellunge caught in Ohio was over 55 pounds and over 50 inches in length. (1-3)



Muskellunge attempting to get over dam (Photo credit Richard Hurd 2014)The return of the muskellunge

The return of the Muskellunge

In the early 20th century, the muskellunge was viewed under the myth of super-abundance as a commercial fish. This means there were no regulations on how many or what size fish could be taken, nor was there any thought to maintaining their habitat. Dams were added in rivers, which disrupted spawning routes, and wetlands were removed to allow for farming or building sites. As a result of this, muskellunge populations in Ohio began to diminish. (1,3)

In the 1950s, the Ohio Division of Natural Resources (ODNR) began restoration efforts of muskie populations by hatching and raising muskellunge and using them to restock different locations throughout Ohio. Habitat loss for the muskellunge does not allow wild muskies to successfully reproduce. Because of this, the ODNR collects eggs and sperm from mature fish and allows the young muskies the hatch to develop in a controlled environment until they are about 10 inches in length, and then reintroduces them into their natural environment. This program, along with a daily catch limit, has allowed the muskie population in Ohio to stabilize. (2-6)

Up for the challenge?

In efforts to help maintain the muskellunge population, anglers are also encouraged to catch and release fish that are less than 30 inches even though there is no state size limit. This allows the muskie a better chance of reaching sexual maturity, which is 3 years for males and 4 years for females. If you are interested in catching a muskie, you can find them in lakes and streams throughout Ohio, such as Alum Creek, Caesar Creek, and Little Muskingum River. They can be found in shallow water during the spring and fall and in deeper water as temperatures increase throughout the summer. They prefer pristine water with a non-muddy, stony bottom. They also like to hide near logs and vegetated areas. (1-3,5)

(Photo credit Zack Hall)


Thanks to the ODNRs restocking program, you have the opportunity to get out there and enjoy the thrill of landing a trophy muskie!





  1. Farrell, J, M., Klindt R, M., Casselman, J, M., LaPan, S, R., Werner R, G., & Schiavone, A. (2006). Development, implementation, and evaluation of an international muskellunge management strategy. Environmental Biology of Fishes, 79:111–123. DOI 10.1007/s10641-006-9091-7.


  1. “Muskellunge”, Ohio History Central, September 20, 2019. https://ohiohistorycentral.org/w/Muskellunge


  1. “Muskellunge Fishing in Ohio”. Ohio Department of Natural Resources, Division of Wildlife. Accessed 9/20/2019. https://wildlife.ohiodnr.gov/portals/wildlife/pdfs/publications/fishing/pub133.pdf


  1. Nohner, J, K., & Diana, J, S. (2015). Muskellunge Spawning Site Selection in Northern Wisconsin Lakes and a GIS-Based Predictive Habitat Model, North American Journal of Fisheries Management, 35:1, 141-157, DOI: 10.1080/02755947.2014.977471


  1. “Ohio Fishing Regulations (2019-2020)”. Ohio Department of Natural Resources, Division of Wildlife. Accessed 9/20/2019. http://wildlife.ohiodnr.gov/portals/wildlife/pdfs/fishing/2019-20%20Ohio%20Fishing%20Regs_WEB.pdf


  1. “The Division of Wildlife’s Muskellunge Management”. (2012). Ohio Department of Natural Resources, Division of Wildlife. Accessed 9/23/2019. http://wildlife.ohiodnr.gov/fishing/fishing-clubs-and-programs/muskie-management



Burbots: One of Erie’s Most Overlooked Species

Picture from American Fisheries Society.

What do you get when you cross a catfish and an eel? The result is an Ohio-native fish called the burbot. Burbots (Lota lota) are the only member of the cod family (Lotidae) that live completely in freshwater (Stapanian et al., 2008). In Ohio, burbots are found primarily in Lake Erie (Rice, D. & Zimmerman, B., 2019). Populations of this species are difficult to study due to their choice in habitat. Burbot need cooler water temperatures in order to survive and reproduce. They spend the warmer months in the deeper, eastern basin of Lake Erie where the water is cooler. In the cooler months, burbot move into shallower waters in the central and western basins of the lake (Trautman, 1997).

Although global burbot populations are doing well, many regional populations are threatened or extirpated. Burbots have been extirpated from Europe and the United Kingdom and are threatened or endangered in most of North America. In Ohio, they are listed as a species of concern. (Ohio Department of Natural Resources, 2012). Because burbot are not a popular commercial fish species, few have considered the species when deciding upon management plans.

One factor that has a large, negative impact on Lake Michigan, Huron and Ontario burbot populations is the sea lamprey. Before sea lamprey populations were controlled and their numbers reduced as a result, they mercilessly preyed upon burbots, causing burbot populations to decline dramatically. In Lake Erie, the main factor influencing the decline in burbot population has been due to a combination of decreased water quality—a result of pollution—habitat degradation, and past overexploitation (Stapanian et al., 2010).

Why is it important that we conserve this species? While they may not be the best game or commercial fishing species, burbot are a fantastic indicator species. An indicator species is an organism that serves as a measure of the environmental conditions that exist in a given locale; meaning, the organism helps highlight certain characteristics within its environment (Encyclopædia Britannica, 2016). Because they are very sensitive to disturbance (changes in their environment), burbot populations can be monitored to help gain insight as to how human actions are impacting burbots’ environment (Stapanian et al., 2010). Burbot population numbers in their cold month habitats can also serve as an indicator of the impacts of climate change. Less burbot will be found in shallow waters as the water temperature rises. Along with burbot, these rising water temperatures can have negative, long-lasting impacts on other biota in Lake Erie.

Link to NOAA CoastWatch Great Lakes Water Temperature Statistics: https://coastwatch.glerl.noaa.gov/statistic/

Picture from Wyoming Fish and Game Department.

In order to help conserve our burbots here in Ohio, there are some easy things we can do to help. We can improve our water quality by reducing the amount of pollution entering our waterways—this can be done by recycling, creating less one-use-plastic waste, becoming educated on the impacts of industrial runoff, etc. We can also help combat habitat degradation by supporting local, regional, state, and national organizations and agencies that are fighting to conserve lands and restore those that were damaged.

Fascinating, borderline bizarre, and scientifically invaluable, the burbot is an Ohio species that deserves our attention. By studying their behaviors, humans are aided by burbots in determining habitat quality in Lake Erie. In this way, we can help conserve their populations and the populations of many aquatic species for generations to come.



Encyclopædia Britannica. 2016. Indicator species. Encyclopædia Britannica, inc. https://www.britannica.com/science/indicator-species. Accessed: 9/23/19

Ohio Department of Natural Resources. 2012. Division of Wildlife. Burbot. http://wildlife.ohiodnr.gov/species-and-habitats/species-guide-index/fish/burbot. Accessed 9/24/19.

Rice, D. & Zimmerman, B. 2019. A Naturalist’s Guide to the Fishes of Ohio. Ohio Biological Survey, Columbus.

Stapanian, M., Bronte, C., Ebener, M., Lantry, B.F. & Stockwell, J.D.. (2008). Status of Burbot populations in the Laurentian Great Lakes. American Fisheries Society. 59:111-130. https://www.fws.gov/midwest/Fisheries/scientific-pubs/p-2007-4.pdf. Accessed 9/24/19.

Stapanian, M. A., Paragamian, V. L., Madenjian, C. P., Jackson, J. R., Lappalainen, J. , Evenson, M. J. & Neufeld, M. D. (2010), Worldwide status of burbot and conservation measures. Fish and Fisheries, 11: 34-56. doi: 10.1111/j.1467-2979.2009.00340.x. Accessed 9/23/19.

Trautman, M. B. 1957. The fishes of Ohio. Ohio State University Press, Columbus.





Shining Sharks

Sharks glow in the dark. This may seem absurd, but recent research into the biofluorescence of fish has uncovered a startling new world of glowing fish. There are currently over 180 fish species that are biofluorescent. This means that the fish can absorb one wavelength of light, then reemit that light but at a lower energy wavelength (Sparks et al. 2014). The most common is absorbing blue light, which is the only type of light in most marine systems and emitting green light. They do this in order to be seen. Many fish, including sharks, have yellow filters in their eyes that would accentuate the biofluorescence of other fish(Sparks et al. 2014).

Park et al

Exactly how this happens in fish is mostly unknown. Only the chemistry behind eel fluorescence has been found until recently researchers unlocked how the swell shark and the chain catshark are able to glow (Park et al. 2019). Traditionally, green fluorescent proteins (GFPs) and other similar proteins have been found to enable bioluminescence, some of which have led to important innovations within the medical community (Park et al. 2019). But the researchers discovered a new type of protein, brominated tryptophan molecules, that enable these sharks to get their glow on. They discovered 8 new molecules in the sharks’ skin that are bioluminescent by using a battery of different methods to determine the shape and makeup of the different molecules, many of which are found more often in a chemistry lab than a biology lab (Park et al).

Park et al 2019

These molecules would seem to also play a dual role for the sharks. Not only do they fluoresce, but some of them actually have antibacterial properties (Park et al. 2019). This is especially important for the swell shark and catshark as they live on the seafloor, which has a much higher concentration of bacteria than the water above. Having these molecules in their skin may actually protect the shark from illnesses contracted from bacteria. There are other properties of these molecules that are unknown, and many other potential molecules in other fish that have yet to be discovered. These sharks and their amazing biology just may shed some light onto other avenues of exploration not just in the field of fish biology, but in fields such as chemistry and medicine.


  1. Park, H. B. et al. Bright Green Biofluorescence in Sharks Derives from Bromo-Kynurenine Metabolism. iScience 0, (2019).
  2. Sparks, J. S. et al. The Covert World of Fish Biofluorescence: A Phylogenetically Widespread and Phenotypically Variable Phenomenon. PLOS ONE 9, e83259 (2014).