Trophic transfer of microplastics from copepods to jellyfish in the marine environment

By Meagan Ando​, SRC intern

 Our oceans face great threats in this day and age. The list is quite expansive, but one such threat is microplastics. Microplastics are tiny bits of plastic, usually around the size of a sesame seed or smaller, that originate from everyday items such as water bottles or straws that find their way into the ocean (Image 1). Because of their size proximity to plankton, many marine organisms ingest these microplastics unknowingly, which can easily accumulate and be passed through trophic levels from zooplankton to fish and to other larger marine animals (Cole et al., 2013; Farrell and Nelson, 2013). Trophic levels are sequential stages in a food chain that comprises primary producers and subsequent primary, secondary, and sometimes tertiary consumers. Each predator/prey interaction involves a fraction of the amount of energy produced/consumed on the previous trophic level, making it possible for the exchange of these microplastics from level to level. This can be quite alarming, especially if these microplastics end up in the fish you eat for dinner in your home. That’s why the study of microplastic transfer between trophic levels is necessary. Although there was some information known regarding this topic, Costa et al. (2020) set out to answer more questions and fill the gap of knowledge regarding the microplastic transfer among zooplankton. This information about zooplankton was vital due to the fact that they are an important link between the primary producing phytoplankton (Turner, 2004), that use the process of photosynthesis to create energy, and the higher trophic levels (Costa et al., 2020).  

In order to simulate a trophic level transfer system, the group created a simple two-level trophic cascade using the nauplii zooplankton species of the T. fulvus copepod as the prey and the ephyrae stage of the Aurelia species of jellyfish as predator (Costa et al., 2020). We know these species for being easy to study because of their large abundance, ease of culturing methods, and their role as excellent models in the evaluation of microplastic contamination. In short, they exposed the zooplankton nauplii to polyethylene microplastics for 6 hours and then offered to the ephyrae jellyfish for 24 hours in order to simulate the consumption of prey in the wild. The amount of consumed microplastics in the zooplankton were examined and verified using fluorescent microscopes to confirm that the nauplii were contaminated and that there was something for the jellyfish to be polluted with. In order to test the negative side effects of the microplastic contamination in the jellyfish, they evaluated both immobility and pulsation frequency in hopes of shedding some light on what ecotoxicological effects these tiny bits of plastics could have on a predator in a short time. Such results were determined using a recording system along with a video graphic analyzer. Immobility percentages, including those jellyfish that were completely motionless, were recorded, along with the pulsation frequency that was calculated using a recording of pulsations in a time frame of 1 minute (Costa et al., 2020). 

Overall, the results found that the jellyfish had in fact ingested microplastics, confirming this physical trophic transfer (Image 2). Quite interestingly, there were not any significant ecological responses because of the influx of microplastics in the jellyfish population; immobility percentages were not statistically significant, and pulsation frequencies were only slightly decreased (Figure 1). To conclude, this group of researchers found that the trophic transfer of microplastics is clear through the indirect ingestion by predators and is significant in the ocean because of the ability of these jellyfish to carry heavy metals in their gelatinous tissues. Also, they agreed that a longer exposure time frame (over 24 hours) could lead to more visible, measurable ecotoxicological effects (Costa et al., 2020). This information is vital in protecting the health and well-being of not only the oceans and the organisms that inhabit it but also our very own family and friends. We can all help take steps in the reduction of microplastics in the environment by reducing our plastic usage (by using reusable items such as water bottles and bags) and recycling those items in which we use. 

Figure 1: Graphic visual showing the pulsation frequencies between uncontaminated jellyfish and jellyfish containing the contaminated copepods (Costa et al., 2020).

Image 1: Example of everyday plastics found on a beach (Tim Hüfner).

Image 2: Set of images showing the trophic transfer after 24 hours. Image A shows the control jellyfish, completely free of contamination. Images B,C show copepod clusters within the jellyfish with white arrows pointing to the polyethylene microplastics (Costa et al., 2020).

Works cited 

Cole, M., Lindeque, P., Fileman, E., Halsband, C., Goodhead, R., Moger, J., et al. (2013). Microplastic ingestion by zooplankton. Environ. Sci. Technol. ​47, 6646–6655. 

Costa, E., et al. (2020). Trophic transfer of microplastics from copepods to jellyfish in the marine environment. Frontiers in Environmental Science​​. Vol. 8. 

Farrell, P., and Nelson, K. (2013). Trophic level transfer of microplastic: Mytilus edulis ​(L.) to Carcinus maenas ​(L.). Environ. Pollut. ​177, 1–3. 

Tim Hüfner via Unsplash. 

Turner, J. T. (2004). The importance of small planktonic copepods and their roles in pelagic marine food webs. Zool. Stud. ​43, 255–266. 

Social adaptive capacity: How coastal fishers will respond to a changing environment

By Peter Aronson, SRC intern

As a pandemic has devastated the entire planet, scientists warn that the accelerating impacts of climate change in the future could be similar, or worse, as they are anticipated to lower productivity in many ecosystems (Asch et al., 2017). This will lead to severe changes to ecosystem services, with dire consequences for humanity (Vitousek, 1997). In the face of global environmental catastrophe, human societies’ futures will depend on social adaptive capacity: the adjustments to current, perceived, or anticipated social and environmental change (Janssen and Ostrom, 2006). By understanding the roles and extents of what determines social adaptive capacity in different circumstances, actions taken to reduce the impacts of environmental changes can be identified (D’agata et al., 2020). Not much research has been done in this area, so a group of scientists studied the social and ecological determinants of social adaptive capacities for fishing communities in East Africa at multiple scales. 

Coastal fishing communities and other resource-dependent communities will face challenges from climate change in coming years. (Cun, 2020).

Researchers conducted surveys with members of over 650 households across 29 fishing-dependent communities in Madagascar and Kenya. They created a composite index of Adaptive Capacity (AC) which ranks households in AC according to a number of indicators. They then assessed the relationship between the index and several social-economic and environmental determinants that were predicted to affect social adaptive capacity at multiple scales (D’agata et al., 2020). They also observed the ecological conditions and management strategies in adjacent coral reef ecosystems using transects to conduct visual surveys of fish and estimate percent coral coverage. They used this data to assess fish biomass and total percent coral cover for all reefs surrounding villages to determine the overall ecological condition.

Markets and market accessibility can be very economically beneficial to fishers and strengthen their social adaptive capacity. (WikiCommons, 2020).

They found that market accessibility was the most influential factor determining fishers’ AC, with middlemen playing an important role (D’agata, 2020). This was followed by climate stress, which decreased AC by about 20%. They also surveyed households on whether they’d change their fishing activities in response to a hypothetical 50% decrease in fish catch. Overall, 95% of surveyed households would stay in fisheries by fishing at a certain level or changing fishing grounds or gear. Households with higher AC scores were more likely to change fishing gear, fish less, or stop fishing, while those with lower AC scores were more likely to keep fishing or fish more if facing halved catches (D’agata, 2020). Interestingly, ecological conditions were not consistently associated with social adaptive capacity, with an inverse relationship observed for 80% of fisher households (D’agata, 2020). This suggests the relationships within social-ecological systems may be complex and could be promotive of social-ecological traps. Scientists are worried that households with lower social adaptive capacities and better ecological conditions will be tempted to exploit resources faster, which will be beneficial in the short term but will lead to resource degradation and poverty in the long term (Cinner, 2011). Further, communities with higher social adaptive capacity, degraded environments, and low interest in exiting fisheries, can be trapped in poverty due to decreasing ecosystem services (Cinner, 2011). Those in poor social-economic conditions with low social adaptive capacity and a degraded environment may already be trapped in poverty (D’agata, 2020). In the future, similar studies should continue to monitor the complex social-ecological relationships, as global environmental changes will have strong social and ecological impacts (Birkeland, 2015; Cinner et al., 2018).   

Works cited

Asch, R.G., Cheung, W.W.L., and G. Reygondeau. 2017. Future marine ecosystem drivers, biodiversity, and fisheries maximum catch potential in Pacific Island countries and territories under climate change. Mar. Policy.

Birkeland, C. 2015. Coral reefs in the anthropocene. Coral Reefs in the Anthropocene.

Cinner, J.E. 2011. Social-ecological traps in reef fisheries. Glob. Environ. Chang. Part A 21, 835–839.

Cinner, J.E., W. N. Adger, E. H. Allison, M. L. Barnes, K. Brown, P. J. Cohen, S. Gelcich, … and T. H. Morrison. 2018. Building adaptive capacity to climate change in tropical coastal communities. Nat. Clim. Chang. 8, 117–123. 

Cun, C. 2020. Kurau fishing village in Central Bangka [Photograph]. WikiCommons.

D’agata, S., E. S. Darling, G. G. Gurney, T. R. McClanahan, A. N. Muthiga, A. Rabearisoa, and J. M. Maina. 2020. Multiscale determinants of social adaptive capacity in small-scale fishing communities. Environmental Science & Policy, 108, 56-66.

Janssen, M.A. and E. Ostrom. 2006. Resilience, vulnerability, and adaptation: a cross-cutting theme of the international human dimensions programme on global environmental change. Glob. Environ. Chang. Part A 16, 237–239. 

Vitousek, P.M. 1997. Human domination of Earth’s ecosystems. Science 277, 494–499.

WikiCommons 2020. The fish market in Mwanza, Lake Victoria [Photograph].

Coral Stress and Conservation

By Morgan Asmussen, SRC intern

The oceans are vital to Earth and its inhabitants as it covers more than seventy percent of the planet and holds about ninety-seven percent of Earth’s water. Climate change, however, is linked to human habits and activity in our daily lives. Climate change occurs with the increase of greenhouse gases due to human activities that involve the burning of fossil fuels for sources of heat and energy, the production of industrial products, raising livestock, fertilizing crops and even deforestation (Trenberth 2001). All of these human activities then cause a buildup of greenhouse gases to heat up our atmosphere. With rising composition of gases in the atmosphere causes the ocean to absorb an excess amount of carbon dioxide and methane leading to many consequences specifically impacting the survivability of coral species on a global scale.  

The ocean regulates global climate and makes the Earth habitable for humans and all of its inhabitants. Carbon dioxide levels that have been measured in Earth’s atmosphere have been at an all-time high and most likely ties to human activity (Rogers 2018). The greenhouse effect is then amplified due to the large amount of gases such as carbon dioxide and methane which hold heat within the atmosphere and warm the Earth. Initially this was seen as beneficial for Earth as a large diverse population of species was then able to flourish at warm temperatures. However, as time went on and temperatures continued to rise, the presence of greenhouse gases rose almost thirty percent (Rogers 2018). Earth contains absorbent oceans which trap this heat and prevent it from reaching uninhabitable temperatures. With higher values of carbon dioxide, the chemistry of the ocean then began to alter which inevitably effected its inhabitants. With rising gas comes ocean acidification leading to a decrease in growth rates and structural integrity of coral reefs.

A warming ocean puts more thermal stress on its organisms causing corals to bleach. Raising the oceans’ temperatures just a few degrees Celsius can cause coral to die. It is similar to human response to an unknown threat. Humans produce a fever and attempt to flush the body as rapidly as possible to remove any foreign bodies. Corals do the same when it comes to a rise in temperature of the waters in which they live in. When the temperature of water rises, corals flush out the essential algae within their polyps as a response to the stress. These algae produce food for the corals, therefore, when corals no longer have access to this symbiotic relationship they begin to bleach. With excess bleaching of coral species comes devastation of marine ecosystems and eventually a negative impact to humankind’s lifestyle, food sources, and living environment as these changes will not just be detrimental to corals and other marine species (Poloczanska et al. 2013). 

One of the most widely used procedures of coral conservation and restoration that has been implemented is coral nurseries and transplants which has been utilized to restore coral populations. Coral transplants are a growing practice in which researchers restore old, dead coral with healthy coral grown by humans. Although this has been successful in many locations, scientists found that transplantation of coral fragments is best utilized when there is (1) a “phase shift” within the communities that have been dominated by soft corals and/or macroalgae which limits the hard corals access to sunlight, (2) natural recruitment is limited within the colony at hand, (3) when donor coral colonies are available and healthy, and (4) when the water quality is favorable in order to promote growth and survival of the donor coral (Rinkevich 2005).

Coral Fragment (Source: Meaghan Johnson,

Corals themselves are vital for the ocean’s ecosystems to survive but they also provide many health benefits for humans. It has been found that corals have possible cancer fighting components. For instance, there is currently a drug called prostaglandin that comes from sea fans and another drug called bryostatin that comes from coral rhizomes which also fights cancer. There has been other medicinal product as a result of marine organisms which have helped researchers with diseases such as Alzheimer’s disease, arthritis and heart disease. Humankind has only explored about eight percent of all world oceans and it has already provided the human species with so much to benefit their health. There is so much that coral reefs have to offer making them even more vital for not just human survival but all species survival. Coral reefs provide includes their ability to serve as a natural breakwater that protects people from large waves and dangerous cyclones that might have otherwise devastated the United States of America’s coastlines. Coral breakwaters are proven to be better than the ones that man can produce, because they’re growing and rebuilding themselves at all the times (Tobler 2012).

Coral Nursery (Source: NOAA Fisheries,

Thirty-eight million people worldwide are currently employed by the fish industry would then left be jobless if there was a devastation if coral and fish populations which may be a reality on the current path Earth and its atmosphere is on. The Caribbean would lose its main source of income if corals were to disappear which would leave people with nowhere to turn. Even human health would suffer due to the medical benefits that corals provide and the advancements the medical world has found through animal species such as sea cucumbers, jellyfish and as discussed previously, coral. There would be complete disruption of biodiversity most likely resulting in mass extinction throughout the animal kingdom (Richardson 2012). Over 62 million people would no longer have the surge protection that corals provide from rises sea level and numerous other unfathomable losses our planet won’t be able to sustain due to coral extinction. 

Coral restoration and conservation are essential for the survival of ocean ecosystems and human economies worldwide. Practices such as transplants and coral nurseries are necessary procedures in attempt to reverse the anthropogenic effects of climate change. They have become very common within the marine science field and support the recovery of the oceans.

Works Cited

Poloczanska ES, Brown CJ, Sydeman WJ; Kiessling W and Schoeman DS. (2013). Global imprint of climate change on marine life. Nature Climate Change 10:919-925

Rogers JW (2018) Climate Change: Science and Threats. The Ocean Portal 2:1-12

Richardson AJ, Brown CJ, Brander K, Bruno JF and Buckley L. (2012). Climate change and marine life. Biology Letters 8:907-909

Rinkevich, Baruch. “Conservation of Coral Reefs through Active Restoration Measures:  Recent Approaches and Last Decade Progress.” Environmental Science & Technology, vol. 39, no. 12, 2005, pp. 4333–4342.

Tobler C, Visschers VH and Siegerist M. (2012). Consumers’ knowledge about climate change. Dordrecht 114:189-209

Trenberth KE (2001) Stronger evidence of human influence on climate: The 2001 IPCC assessment. Environment 43:8-10

Teaching Ocean Stewardship through Board Games

By Megan Buras, SRC intern

When you think about ocean conservation, the last thing that probably comes to mind is board games, but scientists from Northern Germany have found a creative way to link the two (Koenigstein et al. 2020). In order to teach students the cognitive skills required to solve marine sustainability problems, they have developed Ocean Limited, an immersive tabletop game that focuses not only on being educational, but linking ocean stewardship to the actions of each individual. Students play as different characters, such as a shipping company CEO, a journalist, the mayor of a coastal town, a commercial fisher, or even an aquaculture farmer. Each character has an objective to accomplish and has specific actions they can take to fulfill their goal. Depending on the players’ choices, their actions can cause environmental impacts. As time progresses, game events occur (ranging from invasive species’ population booms to oil tanker spills) that impact players’ economic activities and income. Mirroring real-world sustainability issues, the game requires players to collaborate to mitigate these negative impacts. When Ocean Limited was play-tested with students in high school and environmental education groups, they found it was very successful at having players actively take part in a way that promotes an understanding of the interdependency of ocean users and their own direct and indirect environmental impacts (Koenigstein et al. 2020).

A group of students play testing Ocean Limited (Source: Koenigsteing et al. 2020)

This game was specifically developed to be played face-to-face to encourage student participation and minimize distractions that digital games often provide (Koenigstein et al. 2020). However, the global pandemic has required educators to be more creative with actively engaging their students at a distance. While Ocean Limited might not be an option for teachers at this time, other digital games focusing on ocean and environmental stewardship exist. FishBanks is an online multiplayer fishery management game that can teach players to manage renewable resources sustainably while tying in economic context (Newton et al. 2015). Games such as Keep Cool and Climate Quest are other online alternatives that focus more on global climate change policies and protecting fragile ecosystems, but still have a strong emphasis on active participation (Creutzig et al. 2020).

FishBanks is a web-based fishery management game where players must find a balance between maximizing profits and sustainably handling fish stocks (Image source: Meritt Thomas on Unsplash)

Through Ocean Limited, these scientists could show that educating people with games provides a direct understanding of complex real-world issues (Koenigstein et al. 2020). As technology advances, it will open more doors of opportunity to expand how we can teach others environmental stewardship in a meaningful and impactful way.

Works cited

Creutzig, F., and F. Kapmeier. 2020. Engage, don’t preach: Active learning triggers climate action. Energy Research & Social Science 70:101779.

Koenigstein, S., L.-H. Hentschel, L. C. Heel, and C. Drinkorn. 2020. A game-based education approach for sustainable ocean development. ICES Journal of Marine Science.

Newton, E. 2015. A Brief Analysis of Fishbanks and Natural Resource Management Decision-Making Simulation Games: Converting a current NRM game into a web-based application.

How Engine Noise Can Protect Marine Protected Area

By Konnor Payne, SRC intern

Marine Protected Areas (MPAs) are internationally recognized areas of the ocean, with laws in place to protect natural or cultural resources. For instance, the Great Barrier Reef, where goals are to conserve endangered or commercially viable species, promote ecosystem health, and restore species diversity. As of 2018, there were 13,000 MPAs worldwide, contributing to approximately 6.6% of the world’s oceans (Kline et al., 2020). In theory, MPAs provide a haven for habitats of great significance, but in practice, surveying the area to ensure this is costly and resource-demanding. To ensure the laws in an MPA are upheld, either manned surface patrols or aerial patrols are required. Strong enforcement of MPA laws have been associated with a rapid increase in the numbers and density of otherwise targeted species (Kline et al., 2020). However, most methods of monitoring cannot be used every hour of every day, which leaves the MPAs susceptible to illegal fishing and pollution. 

This Marine Protected Area in Australia serves as a sanctuary for the species that live there. (Riccardo Trimeloni via

In this study led by Dr. Kline, a research team proposes a cost-effective and efficient solution to protecting our MPAs. The study tests a passive acoustic monitoring (PAM) system using three acoustic recorders (Soundtrap 3000) which can detect the acoustic signatures produced by the propeller blades and engines of boats. The PAM system was installed in Australia within Cod Grounds Marine Park (CGMP) and Solitary Islands Marine Park National Zone (SIMP NPZ), chosen for their proximity to boat ramps and significant vessel usage. Illegal fishing is known to occur here, as these locations are home to snapper, pearl perch, and yellowtail kingfish (Kline et al., 2020). From July 1st to September 12th, 2018, the PAM recorded the sounds of 41 vessels within CGMP and 34 vessels within SIMP NPZ. By analyzing the acoustics picked up in the water, the researchers could give a rough generalization of the size and behavior of the vessels recorded. They could only accomplish this with strong enough acoustic signatures, which likely excluded vessels that were drowned out by biological noises. 

Illegal fishing counteracts the goals of Marine Protected Areas (Tadeu Jnr via

Patrols were set to maximize vessel detection by being most active during holidays, weekends, lunar cycles, early mornings, and evenings, when infractions were most expected. However, the study found that the vessels within the CGMP in noncompliance were most active on Thursdays and Saturdays on a regular schedule between the hours of 6-11 am AEST. Within the SIMP NPZ, a similar consistent pattern was found on Thursdays between the hours of 3-6 pm AEST. These patterns indicate that people may be taking an extended weekend to capitalize on fishing from Thursday through the weekend (Kline et al., 2020). The incorporation of PAM systems in MPAs to provide the data of where and when illegal vessels are fishing coupled with manned patrols could significantly reduce the illegal activities and boost deterrence. If real-time acoustic systems could be utilized, the acoustic recorders could triangulate the location of vessels within MPA boundaries that would alert the park managers.  

Works Cited 

Jnr, Tadeu. Landscape Photography of Sailing Boat During Golden Hour.

Kline, L. R., DeAngelis, A. I., McBride, C., Rodgers, G. G., Rowell, T. J., Smith, J., … & Van Parijs, S. M. (2020). Sleuthing with sound: Understanding vessel activity in marine protected areas using passive acoustic monitoring. Marine Policy, 120, 104138.

Trimeloni, Riccardo. Body Wave of Water Near Rocks.

The Power of Propagules: Restoring Coastal Marine Ecosystems

By Nina Colagiovanni, SRC intern

As the health and extent of coastal marine ecosystems are at risk worldwide, scientists are working diligently to reverse the damage done. Propagules––structures such as fruits, seeds, larvae and more––act to propagate an organism into the next stage of its life-cycle. They can last from days to months or remain dormant until satisfactory conditions are present. However, scientists are still learning more about how propagules can be used successfully. Research conducted by Vanderklift et al. in 2020 has analyzed the life histories of main habitat-forming taxa in six coastal marine ecosystems: mangrove forests, tidal marshes, seagrass meadows, kelp forests, coral reefs and bivalve reefs. 

But you may wonder, why is this research important? Well, restoration efforts will help increase survival rates of species that cannot thrive in degraded ecosystems. And, in addition, ecological restoration can be a nature-based solution to problems that humans face, such as food security and climate change (Vanderklift et al. 2020).

A mangrove tree in the Florida Keys [Photo by Hayden Dunsel via Unsplash]

One example of propagule usage is mangroves, pictured in Figure 1. Mangrove trees are a diverse group of small trees or shrubs that occur worldwide. Their propagules can float for up to a few days, allowing currents to disperse them, and this is a major advantage (Vanderklift et al. 2020). Mangroves also offer a variety of other traits in which scientists can use to establish restoration techniques, some of which have been used for a long time..

Examples of how propagules are used in restoration [Source: Vanderklift et al. 2020]

Figure 2 shows eight ways in which propagules are prepared and used in restoration. A majority of these methods rely on collection and planting, such as in (a) and (b), while others like (c) use nurseries or aquaria and are more time-consuming (Vanderklift et al. 2020).

This research expressed many challenges faced by scientists. Unlike mangroves, coral reefs––pictured in Figure 3 below––pose a bigger task for scientists. Research has found that while corals regrow from their fragments, it can be both labor-intensive and limiting to specific coral taxa (Vanderklift et al. 2020). While some recovery techniques are worthwhile, they will rarely fully replace a lost habitat (Elliot et al. 2007). But as some of the greatest threats to biodiversity include habitat loss and disturbance, scientists must understand and assess restoration methods (Milbrandt et al. 

A coral reef in the Red Sea [Photo by Francesco Ungaro via Unsplash]

Propagules can restore a large area of a specific ecosystem, as well as be dispersed to different locations. Thus, they are a powerful tool for researchers. Not only does the health and extent of coastal marine ecosystems rely on the locations analyzed in this research, but working to reverse the degradation will also aid in resolving problems that humans face, such as food security, climate change and susceptibility to natural disasters (Vanderklift et al. 2020). While better techniques are still being explored, propagules will continue to aid in coastal marine ecosystem restoration efforts on a global scale.

Works cited

Elliott, M., Burdon, D., Hemingway, K. L., & Apitz, S. E. (2007). Estuarine, coastal and marine ecosystem restoration: confusing management and science–a revision of concepts. Estuarine, Coastal and Shelf Science, 74(3), 349-366.

Milbrandt, E. C., Thompson, M., Coen, L. D., Grizzle, R. E., & Ward, K. (2015). A multiple habitat restoration strategy in a semi-enclosed Florida embayment, combining hydrologic restoration, mangrove propagule plantings and oyster substrate additions. Ecological Engineering, 83, 394-404.

Vanderklift, M. A., Doropoulos, C., Gorman, D., Leal, I., Minne, A. J., Statton, J., … & Wernberg, T. (2020). Using propagules to restore coastal marine ecosystems. Frontiers in Marine Science, 7, 724.

The Importance of Connectivity in Marine Reserve Performance

By John Proefrock, SRC intern

Marine Reserves are essential parts of ocean conservation across the world. They provide protection for sensitive species and prevent overfishing in areas essential for the recovery of those species. The effects of overfishing include a massive disruption of the marine food web which can cause dangerous rises in primary producers due to the removal of predators in the upper trophic levels (Scheffer, M. et al 2005) The benefits of individual marine reserves have been shown, but reproduction patterns are variable between each reserve, which leads to fluctuations in the replenishment of each individual population. A large-scale study of the effect of a group of reserves on the population replenishment of highly pressured species had yet to be conducted, which is what the Australian Research Council Centre of Excellence for Coral Reefs aimed to accomplish. The study focused on the contribution of four marine reserves to the repopulation of coral grouper (Plectropomus maculatus) on the Great Barrier Reef. The investigation of the contribution of each reserve was performed by analyzing the age of sampled fish and determined that there were 6 distinct spawning events across the 4 reserves.

A coral grouper (Plectropomus maculatus), also known as the coral trout, is a common fish throughout Australian waters, including the Great Barrier Reef. (Source: Wikimedia Commons)

They calculated the population size and reproduction from each reserve using this data, along with underwater observations and genetic analysis. Using the collected data, it was clear that the individual reserves do generate a large proportion of the local population. However, the benefits were unpredictable in terms of timing and location. 

The interesting finding from this study came when looking at the relationship between these spawning events. Each reserve produced a new generation (i.e., a cohort) at a different time. This asynchronous portfolio of reserves allows for a reliable replenishment of the coral grouper population on the Great Barrier Reef since the larval dispersion from each reserve benefits all the others. This is similar to the effect of diversifying a stock portfolio in order to protect against dips in the stock market. If there are multiple sources of coral grouper larva dispersing, then there will be more stable recruitment to the adult population. Overfishing has been an ever-present issue in marine since the 1950s, as the demand for oceanic protein has risen, and with it has come the overexploitation of these resources which may never recover if left unprotected (Coll et al. 2008). 

A sablefish (Anoplopoma fimbria) on the seafloor. This is a commonly harvested fish in the North Pacific. (Source:

Using this study, we can improve the management of many fish populations. For example, sablefish (Anoplopoma fimbria) in the Canadian Pacific were managed based on retention of biomass, with no attention being paid to the longevity of the population. However, the productivity of younger fish was significantly lower than that of older fish (Beamish et al. 2006) As the older fish were removed disproportionately, the per-year replenishment of the population slowly declined. These studies can help to better inform marine conservation for other fish species and ensure that there is a steady output and replenishment of these key protein sources for families around the world. The future of our ocean ecosystems depends on the actions taken now to protect these crucial resources from decimation.

Works Cited

Scheffer, M., Carpenter, S., & Young, B. (2005). Cascading effects of overfishing marine systems. Trends in Ecology & Evolution, 20(11), 579-581. doi:10.1016/j.tree.2005.08.018

Coll, M., Libralato, S., Tudela, S., Palomera, I., & Pranovi, F. (2008). Ecosystem Overfishing in the Ocean. PLoS ONE, 3(12). doi:10.1371/journal.pone.0003881

Beamish, R., Mcfarlane, G., & Benson, A. (2006). Longevity overfishing. Progress in Oceanography, 68(2-4), 289-302. doi:10.1016/j.pocean.2006.02.005

The Great Barrier: The Road to Blue Restoration

By Oliver Topel, SRC intern

This blog post covers the scientific paper Blue Restoration–Building Confidence and Overcoming Barriers, written by Phoebe J. Stewart Sinclair et al. The main subject of this paper is a process called “Blue Restoration,” which is the interventions made for the rehabilitation of marine and coastal habitats. Some examples of these are salt marshes, coral reefs, and tidal flats. Until recent years, restoration efforts have been focused more on terrestrial areas, but this focus is slowly shifting to encompass marine areas. For blue restoration to be effective, however, practitioners must overcome five distinct barriers: environmental (land conversion, water quality, human-made issues), technical (site selection and potential capacity), social (public perception and community engagement), economic (financing and insurance), and political (government policies). 

Figure 1, image of the five classes of barriers (Source: Sinclair et al. 2020)

While these barriers are difficult to overcome, doing so could lead to exponential improvement in marine and coastal habitats. If blue restoration is successful, it would not only lead to great improvements to biodiversity, but could even mitigate anthropogenic climate change.

In order to expand upon these barriers, the research paper examines four restoration efforts, two of which taking place in Sulawesi, Indonesia, with the other two based in Chesapeake Bay, United States. The four restoration sites illustrate barriers, how to work around them, and how to solve issues. One of these was a coral reef in Sulawesi, Indonesia. Storms, coral mining, and other disturbances caused a coral rubble field, displaying a technical barrier (Williams et al., 2019). The project solved this by deploying structures known as ‘spiders’ (see picture below) to stabilize the rubble and support transplanted coral. After two years, live coral cover went from less than 10% to greater than 60%. 

Figure 2, image of ‘spider’ structures, Source: Frontiers in Marine Science

The second of these took place in a shellfish ecosystem in Chesapeake Bay, United States, where oyster restoration was at the center of this project. The eastern oyster (see image below) provides food, water filtration, and more to the local ecosystem and to fisheries. However, due to overfishing and disease, oyster populations have dropped to less than 10% of the average (Wilberg et al., 2011). This being a political barrier, increasing the eastern oyster’s numbers has been a collaboration across several jurisdictions. These efforts are believed to restore the populations of both finfish and shellfish by 2025 (Chesapeake Bay Program, 2019).

Figure 3, image of eastern oysters, Source: NOAA Fisheries

With these projects and many more throughout the world, conservationists and marine affairs workers are putting significant time and effort into the blue restoration. Understanding the five classes of barriers is essential in assuring success of the blue restoration, because even if one barrier is overcome, another can easily undo the headway made. Spreading the information about the successes of these projects is very important, allowing to inspire and educate people on the importance of the blue restoration and all the good it can do for the Earth.

Works cited

Stewart-Sinclair, P. J., Purandare, J., Bayraktarov, E., Waltham, N., Reeves, S., Statton, J., … & Lovelock, C. E. (2020). Blue Restoration–Building Confidence and Overcoming Barriers. Frontiers in Marine Science, 7, 748.

Williams, S. L., Sur, C., Janetski, N., and Hollarsmith, J. (2019). Large-scale coral reef rehabilitation after blast fishing in indonesia: coral reef rehabilitation. Restor. Ecol. 27, 447–456. doi: 10.1111/rec.12866

Wilberg, M. J., Livings, M. E., Barkman, J. S., and Morris, B. T. (2011). Overfishing, disease, habitat loss, and potential extirpation of oysters in upper Chesapeake Bay. Mar. Ecol. Prog. Ser. 436, 131–144. doi: 10.3354/meps09161

Chesapeake Bay Program (2019). Chesapeake Progress. Available online at:

Traditional knowledge of Fishers versus an environmental disaster from mining waste in Central Brazil

By Rebecca Varnam, SRC intern

In recent years, the depths of human impacts on the environment have become even more clear (Nyssen, 2004). These impacts are not just specific events that occur in single, isolated locations, but rather multiple events that occur around the world, and in multiple different forms (Phillips, 2001). Here, I am going to focus specifically on a study from Oliviera et al. (2020) on how mining waste released into the Doce River affected artisanal fisheries, following the collapse of a dam associated with the Samarco Mineração (SA) mining company (Figure 1). Assessed are the three different regions in Central Brazil; Conceição da Barra (CB), Regência (RG), and Barro do Riacho (BR). 

Map of Doce River, including the Southeastern Brazil dam setup and the collapsed dam location that caused the release of mining waste closest to the three regions assessed in this paper: CB, RG, and BR (Magris, 2019).


Scientists spent about four months performing assessments and interviews in the three central Brazilian regions mentioned above. The procedure began with habitat assessments in each location based on observation and research on the areas before, during, and after the disaster. They completed 120 interviews-to avoid bias, these were performed individually and using a standard questionnaire (Oliviera et al., 2020). The information was then gathered and organized to allow scientists to make conclusions on the impacts this disaster had within this area. 

Overall, most fishers mentioned the following, “1) fishing was suspended, 2) the catch was contaminated and its volume decreased and 3) there was degradation in the Doce River basin as far as the river mouth” (Oliviera et al., 2020, p. 4) (Figure 2). These three impacts play a role in not just the environmental health of these designated regions, but also success in the fishing market.

Doce River after the dam collapse in Central Brazil, (B) “Toxic Mud” that accumulated in Doce River (Oliviera et al., 2020).

You may wonder why it was important for these scientists to perform this study. First, there are about 40 million people worldwide that have livelihoods that rely on marine fisheries (FAO, 2018). With this many people relying on fisheries, it is important that changes to this industry are available to not only help the environment but also to protect these families from economic deficits. Second, mining companies establishing in a region can increase aquatic environmental concerns such as increased pollution, contamination, and changing landscapes and ecosystems, which can also affect fisheries within the region (Kossoff et al., 2014). With these environmental concerns and impacts on fisheries, there is an increased need for more research to find the most sustainable and safe methods for mining and dam usage.

In conclusion, this environmental disaster, recognized by most to be the fault of SA mining company, has affected fishers in CB, RG, and BR regions to reduce their fishing practices to only supply for their families as they do not have the money to access other food sources. Fishers are also struggling, as a majority do not have the education to access other job opportunities. Further assessments on the continued impact of this disaster is necessary along with more employment opportunities provided by the SA mining company for those struggling to provide for their families (Olivier et al., 2020). 

Works cited

Kossoff, D., Dubbin, W. E., Alfredsson, M., Edwards, S. J., Macklin, M. G., & Hudson-Edwards, K. A. (2014). Mine tailings dams: Characteristics, failure, environmental impacts, and remediation. Applied Geochemistry, 51, 229-245. doi:

FAO, The State of World Fisheries and Aquaculture 2018 – Meeting the Sustainable Development Goals, Food and Agriculture Organization of the United Nations, Rome, Italy, 2018.

Nyssen, J., Poesen, J., Moeyersons, J., Deckers, J., Haile, M., & Lang, A. (2004). Human impact on the environment in the Ethiopian and Eritrean highlands—a state of the art. Earth-Science Reviews, 64(3), 273-320. doi:

Oliveira, P. D. C., Di Beneditto, A. P. M., Quaresma, V. d. S., Bastos, A. C., & Zappes, C. A. (2020). Traditional knowledge of Fishers versus an environmental disaster from mining waste in Central Brazil. Marine Policy, 120, 104129. doi:

Magris, R. A., Marta-Almeida, M., Monteiro, J. A. F., & Ban, N. C. (2019). A modelling approach to assess the impact of land mining on marine biodiversity: Assessment in coastal catchments experiencing catastrophic events (SW Brazil). Science of The Total Environment, 659, 828-840. doi:

Phillips, J. D. (2001). HUMAN IMPACTS ON THE ENVIRONMENT: UNPREDICTABILITY AND THE PRIMACY OF PLACE. Physical Geography, 22(4), 321-332. doi:10.1080/02723646.2001.10642746


I can hear you: the effects of shipping on the behavior of Arctic cod (Boreogadus saida)

By: Victor Bach Muñoz


When people think about noise in the ocean, they may think about negative effects on species that are known to be vocal in popular culture, like cetaceans (Ellison et al. 2012). However, whales and dolphins are not the only species affected by the increasingly abundant anthropogenic marine noises, as studies on fish have previously demonstrated (Simpson et al. 2016). Much of this marine noise comes from boat traffic, which quadrupled in only two decades at the beginning of the century, raising concerns among scientists about how marine communities may be affected (Tournadre 2014). However, until now, the Artic marine habitats had remained relatively spared by the this increase in shipping activities, mainly due to the Arctic’s sea ice cover. However, climate change has been severely affecting the Arctic sea ice extent during summer months, reducing it by 49% from the 1979 to 2000 baseline average in 2012 (Overland & Wang 2013). This phenomenon is now opening greater boat traffic opportunities through the Northwest Passages, including the Parry Channel (Figure 1).

Figure 1: Map of the Northwest Passage routes and location of Resolute Bay, Nunavut, Canada (Source: Ivanova et al. 2012)

In 2012, Ivanova et al. conducted a study in Resolute Bay, Canada, to find out if sound from ships was influencing the movement patterns of an important polar species: the Arctic cod (Boreogadus saida). The researchers recorded the sound produced by the different types of ships traveling through the bay and tagged 85 Arctic cods (Figure 2) with acoustic transmitters (although only 77 where ultimately used to obtain data). Acoustic receivers in the bay where then used to triangulate the position of the tagged fish as the experiment unfolded, resulting in 11.852 detections between the months of July and September. The movements of Arctic cods where then compared to several variables including ship noise but also marine mammal presence, daily dissolved oxygen, water temperature, salinity, wind speed and wind direction. The results showed that the fish were having a negative response to the noise produced by ships, relocating to other parts of the bay away from those. Furthermore, the potential behavioral changes for the species could have extended ramifications to the many polar inhabitants that depend on it, from seabirds and toothed whales to all Arctic indigenous people.

Figure 2: Two Arctic cods (Boreogadus saida), also known as polar or boreal cods (Photo by Wikifranki from the Creative Commons)

As our planet’s ecosystems keep being affected by climate change, mankind is likely going to look for ways to make the best out of a bad situation. However, while the retreat of Arctic sea ice may offer new possibilities for shipping through the Northwest Passages, it is important to consider the impact that those newly more abundant human activities could have on those relatively pristine environments. While we navigate the surface in look for progress, the underwater communities that provide food and life are listening to our uproar, and it may be just too loud for them.


Work cited:

Ellison, W. T., Southall, B. L., Clark, C. W., & Frankel, A. S. (2012). A new context‐based approach to assess marine mammal behavioral responses to anthropogenic sounds. Conservation Biology26(1), 21-28.

Ivanova, S. V., Kessel, S. T., Espinoza, M., McLean, M. F., O’Neill, C., Landry, J., … & Fisk, A. T. (2019) Shipping alters the movement and behavior of Arctic cod (Boreogadus saida), a keystone fish in Arctic marine ecosystems. Ecological Applications, e02050.

Overland, J. E., & Wang, M. (2013). When will the summer Arctic be nearly sea ice free?. Geophysical Research Letters40(10), 2097-2101.

Simpson, S. D., Radford, A. N., Nedelec, S. L., Ferrari, M. C., Chivers, D. P., McCormick, M. I., & Meekan, M. G. (2016). Anthropogenic noise increases fish mortality by predation. Nature communications7, 10544.

Tournadre, J. (2014). Anthropogenic pressure on the open ocean: The growth of ship traffic revealed by altimeter data analysis. Geophysical Research Letters41(22), 7924-7932.