Tuesday, September 21, 2021

Dazzling Dolphins in Decline: Conflicts between Conservation and Fisheries

 Guest post by recent UTSC MEnvSc graduate, Samantha Lalonde

How do some people seem to know which career they are going to pursue seemingly before they can even walk? Do they just wake up one morning and decide that they want to be a dentist? In my case, I had no idea what I wanted to do all throughout primary school and most of high school. Then, I was presented with a life-changing opportunity.

 In high school, I was offered the chance to volunteer in the Amazon rainforest in Peru with Operation Wallacea3, a conservation research organization. I lived on a riverboat in the Pacaya Samiria National Reserve4 where I completed field surveys of birds, reptiles, fish, and plants with local and international researchers. I quickly realized that I enjoyed doing field work and studying populations of species. But it was one particular morning, while we were gliding peacefully along the narrow river in our small boat, that I realized that I wanted to pursue studies in conservation. A sound broke the silence; the unmistakable sound of a dolphin breaching the surface of the water to breath. It was then that I was introduced to the dazzling pink river dolphin. I had never even heard of these unique charismatic animals until embarking on this trip. But I couldn’t imagine how anyone, after seeing these creatures, could ever harm them.

After pursuing a degree in environmental science and studying the complex ecological, social, and economic factors surrounding conservation science, I now understand that life isn’t as simple as I thought it was in that moment. People have differing beliefs, priorities, and opportunities for education. All of this to say that the Amazonian river dolphins are in decline, and I’m here to explain to past me (and present you since you’re here) why their conservation isn’t such a clear-cut matter.

Boto river dolphin – Mr Devotor / Charismatic Planet1  

Tucuxi river dolphin – Gregory R. Mann / Ocean Treasures2  

The Amazon basin is home to two dolphin species – the boto or Amazon river dolphin and the tucuxi dolphin. The boto dolphin is larger and completely pink, compared to the tucuxi dolphin, which has a pale pink stomach. The International Union for Conservation of Nature5 (IUCN), an organization working on conservation and sustainable use of natural resources, has assessed both dolphin species under the IUCN Red List6. The IUCN Red List provides information on global species habitat and ecology as well as threats they are facing. Tucuxi was classified as “Data Deficient” in 20107, meaning that there is limited information on the threats, ecology, and population trends for this species. Up until recently, the boto dolphin was also listed as “Data Deficient”, but in 2018, it was uplisted to “Endangered”8 due to studies showing large declines in their numbers.

The uplisting of the boto dolphin to “Endangered” by the IUCN was in part influenced by a study by da Silva and colleagues9 in 2018 that looked at long term changes in river dolphin populations. In this study, dolphin surveys were completed monthly from 1994 to 2017 in one of the largest conservation areas of the Brazilian Amazon – the Mamirauá Sustainable Development Reserve (MSDR). Despite being legally protected8 (bans on commercial fishing in the reserve), the number of botos counted during the surveys halved every 10 years, and the number of tucuxi every 9 years. Why was this happening? The areas in which the researchers were doing their surveys had not significantly increased in human population, food sources for the dolphins were still abundant, and the region had not been affected by dams or mining. The researchers concluded that there was no other obvious reason for declines in dolphin populations other than fishery-related mortality. They noted that the human population in Amazonia is growing rapidly, and so too is their demand for fish. The use of gillnets (a wall of netting that hangs in the water column) was found to have greatly increased during the two decades that the researchers study took place.

Gillnets catch fish that swim into it and catch them by their gills S. Maugeri / FAO10

A recently published study by another group of researchers, Campbell and colleagues11, looked into how fisheries and river dolphins are interacting in the Peruvian Amazon. They used questionnaires that asked about fishing habits, fisher interactions with dolphins, and fisher perceptions and beliefs regarding boto and tucuxi dolphins. Community members who were not directly involved in fishing were also given questionnaires to gather information about beliefs and perceptions about river dolphins and the selling of dolphin body parts.

Most fishers interviewed by the researchers had a negative perception of river dolphins and stated that they had had conflicts with dolphins in their fishing areas. The biggest problems they reported were dolphins getting tangled up in their nets and damaging fishing gear, dolphins stealing fish, and boto dolphins being aggressive towards their boats. These have economic impacts for fishers.

A big problem in dolphin conservation is dolphin by-catch, where fishers are trying to catch specific types of fish but unintentionally also catch dolphins. The study estimated a minimum of 182 dolphins being unintentionally caught per year across the fishers they surveyed. Given this, there may be upwards of 2,000 dolphins being bycaught over the entire area they sampled when you take into account the estimated 9735 fishers working in the area. Even this is a conservative estimate, given that the catching of dolphins is illegal, and so the fishers who filled out the questionnaires likely reported fewer catches than they would have otherwise. Bycaught dolphins may be released alive, dead, or kept and sold as bait or for traditional use. A third of fishers reported knowing someone who used dolphin parts as bait, and 56% of community member reported knowing where dolphin parts were sold. However, only 26% of community members stated that they knew that river dolphins were a legally protected species. River dolphins are primarily used as bait for the rapidly expanding piracatinga (catfish) fishery in South America, despite this practice being illegal.

In 2015, the Brazilian government announced a 5-year prohibition12 on the sale and trade of piracatinga with the intention of putting an end to dolphin hunting. River dolphin conservation is challenging because these fishers have no economic alternatives and there is limited presence of governmental organizations and strategies to help deal with this13. Fishing is practiced by most families living by the river in these areas to meet basic needs and is also one of the leading economic activities in the Amazon. The annual revenue of fishing activities is approximately 80 million USD in the Peruvian Amazon basin11. It is not surprising then, that the fishers in the state of Amazonas immediately pushed for a reduced length of the ban14.  Additionally, in their paper, da Silva and colleagues saw no improvement in dolphin numbers from 2015 to 2017, and suggested that this ban was widely ignored9.

I have come a long way since that first glimpse into conservation science all those years ago in Peru. I know now that when we see these types of debates, we have to remember that conservation is complex, and everyone has different opportunities, perceptions, and priorities. Conservation isn’t just about counting animals from a riverboat. Efforts to safeguard species have to consider the ecological, economic, and social factors surrounding an issue to truly be effective. In this case, clear and enforceable regulations have to be put in place by the government to protect river dolphins. The 5-year ban on piracatinga sale, for example, expired in January 2020 and has not been renewed15. Research into population trends must continue, as well as ways to decrease bycatch. Finally, increased efforts must be put into decreasing the economic reliance of fishers on the sales of river dolphins for bait in the Amazon basin.

Although the thought of juggling all these components of conservation can seem daunting at times, the challenge and the reward of successful conservation and management are worth the effort. I can only hope that more people will rise to the challenge to help the animal that ignited my passion for wildlife conservation all those years ago.


1.        Mr Devotor. The Facts of Amazon River Dolphins. https://www.charismaticplanet.com/facts-amazon-river-dolphins/ (2019).

2.        Mann, G. R. Tucuxi Dolphin. 2019 http://otlibrary.com/tucuxi-dolphin/.

3.        Operation Wallacea. Conservation Research Expeditions. https://www.opwall.com/ (2020).

4.        PROMPERU. Pacaya Samiria Nature Reserve. https://www.peru.travel/en/attractions/pacaya-samiria-national-reserve.

5.        IUCN. International Union for Conservation of Nature . https://www.iucn.org/ (2020).

6.        IUCN Red List. The IUCN Red List of Threatened Species. https://www.iucnredlist.org/ (2020).

7.        Secchi, E. Sotalia fluviatilis. The IUCN Red List of Threatened Species 2012. e.T190871A17583369. https://dx.doi.org/10.2305/IUCN.UK.2012.RLTS.T190871A17583369.en (2020).

8.        da Silva, V. et al. Inia geoffrensis. The IUCN Red List of Threatened Species 2018: e.T10831A50358152. https://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T10831A50358152.en (2018).

9.        Da Silva, V. M. F., Freitas, C. E. C., Dias, R. L. & Martin, A. R. Both cetaceans in the Brazilian Amazon show sustained, profound population declines over two decades. PLoS One 13, e0191304 (2018).

10.      Maugeri, S. fishing with bottom gillnets. FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS FAO http://www.fao.org/3/X6935E/X6935E00.htm (1980).

11.      Campbell, E. et al. Coexisting in the Peruvian Amazon: Interactions between fisheries and river dolphins. J. Nat. Conserv. 56, 125859 (2020).

12.      IUCN – SSC Cetacean Specialist Group. Amazon dolphins as fish bait: Brazil introduces a moratorium on piracatinga fishing. https://iucn-csg.org/amazon-dolphins-as-fish-bait-brazil-introduces-a-moratorium-on-piracatinga-fishing/ (2019).

13.      Trujillo, F., Crespo, E., Van Damme, P. A. & Usma, J. S. The Action Plan for South American River Dolphins 2010-2020. (WWF, Fundación Omacha, WDS, WDCS, Solamac, 2010).

14.      InfoAmazonia. Pescadores do Amazonas querem reduzir tempo da moratória da piracatinga (EN: Fishermen from Amazonas want to reduce the moratorium on piracatinga). 2015 https://infoamazonia.org/pt/2015/03/amazon-fishermen-want-to-reduce-time-of-moratorium-on-piracatinga-fish/#!/story=post-12510&loc=-4.389559200000014,-64.55674760000001,7.

15.      Mongabay - EcoWatch. Brazil’s Amazon River Dolphin Faces Extinction After Fishing Moratorium Ends. https://www.ecowatch.com/amazon-river-dolphin-2646191674.html?rebelltitem=1#rebelltitem1 (2020).

Tuesday, June 15, 2021

Increasing diversity of COVID-19 strains: insights into evolutionary divergence and public health

 To be clear, I am not a virologist, nor am I a public health expert. But I do know how to analyze patterns of evolutionary diversity. Research into the SARS-CoV-2 virus that has given rise to the COVID-19 pandemic has greatly enhanced our understanding of global disease dynamics, mRNA vaccines and public health responses to a global crisis. But the COVID-19 pandemic also has the potential to provide fundamental insights into basic ecological and evolutionary processes. 

While a lot has been written about how COVID-19 lock-downs have had noticeable repercussions on air quality and wildlife in cities, the virus lends itself as a microcosm into natural world dynamics. SARS-CoV-2 is now the most studied non-human organism on Earth, and we've witnessed its spread across the globe (which provides insights into invasion biology), it has spread exponentially in populations at times (showcasing the power of models to predict spread), and its rapid diversification is evolution in real time.

Understanding how SARS-CoV-2 strain diversity is generated is of fundamental importance for public health policies. And SARS-CoV-2 is evolving and diversifying. In Ontario, Canada, we have a wonderful resource from Public Health Ontario that publishes data on the evolution of strain diversity and provides a wonderful graphical interface. This interface focuses on the SARS-CoV-2 phylogeny (that is the evolutionary family tree connecting strains to their ancestors) in Ontario.

An example phylogeny

Using their open data, I addressed a simple question, is the evolutionary diversity (measured by the distances separating strains) increasing over time?

To test this, I calculated a statistical measure called the standardized effect size of the mean pairwise distances (SES.MPD) which quantifies the average distances separating strains standardized by random permutations (in this case 500 randomizations) so that a SES.MPD value of 0 means that the evolutionary diversity of a group of strains is no different than a same number of strains randomly selected from the phylogeny. Negative values mean that strains are more closely related on the phylogeny than you expect by chance (referred to as under-dispersed), and positive values mean strains are more distantly related (over-dispersed). I did these calculations for each month since the pandemic hit Ontario (March 2020) and for the seven different regions of Ontario.

Analysis of the standardized effect size of the mean pairwise distances (SES.MPD) of SARS-CoV-2 strains across the seven regions in Ontario since the start of the pandemic. The dashed horizontal line indicates a value of 0 (no different than random expectation) and points outside of the grey box are statistically significantly different than random.

What I found was that early on in the pandemic, the strains were under-dispersed, meaning that they were more closely related and genetically similar than expected by chance. But over time the dissimilarity between strains increases and by May 2021 (the last data in the graphs), many of Ontario's regions had significantly over-dispersed strains. This means that strains found in the populations in May 2021 were generally more dissimilar from one another than early on.

Why this matters is that vaccines and other treatments are typically developed on a single strain or from samples collected at a specific time point. If strains are relatively genetically similar, then it is highly probable that treatments will be successful across the strains. However, as strains diversify and become more dissimilar, then treatments might become less effective overall. 

Had the spreading infection been dominated by single strains, with very few newer strains replacing older ones, we would expect that the SES.MPD values remain below zero, and would make it easier to track strains and adapt treatments.

These patterns are also valuable for insights into ecology and evolution. We often look at SES.MPD values to interpret how different processes structure diversity (like competition, predation, pollution, etc.), but we often don't have good evidence of how historical evolutionary processes can drive SES.MPD differences. The plots above show that rapid evolutionary diversification results in linearly increasing SES.MPD values.

Friday, March 26, 2021

Podcast: Burrow-dwelling solitary bees and the winter of their demise



Guest podcast by UTSC Biology students: Gillian Sauder and Nyx Radu

Burrow-dwelling solitary bees determine their entry into winter diapause based solely based on temperature, this raises the question; are rising global temperatures delaying diapause in these bees? And how will these diapause delays impact their limited energy reserves and survival rates? Find out on the first and only episode of the hit podcast that one person described as "as educational and depressing as a real conservation biology degree" and which alien archaeologists will describe as "an exemplary demonstration of humanity's damning tendency to joke about their problems rather than fix them."  Life: How It's All Dying (Winter Edition) is available now on a blog near you.

Thursday, March 18, 2021

COVID-19 and nature: Is wildlife conservation also in “lockdown”?

Guest post by Nina Adamo, Masters of Environmental Science Candidate at the University of Toronto-Scarborough

Within the surge of news coverage for the COVID-19 pandemic, you may have heard about the increase in the reporting of wildlife sightings in some urban areas across the globe, such as in this CBC article. With less people venturing outside of their homes in efforts to prevent the spread of the coronavirus, the media in multiple countries around the globe have been reporting more sightings of wildlife that are usually rarely or uncommonly seen in suburban and urban areas.6,7 This was the case when a herd of Kashmir goats were seen strolling through the deserted streets of a town in Wales during the lockdown.7

A herd of Kashmir goats roaming the empty streets of a town in Wales.3

This also happened in Toronto, Canada this past summer, where foxes were seen denning in typically busy areas of the city during lockdown.2 To read more about the Tale of Toronto’s boardwalk foxes, check out this article in Maclean’s magazine. What does this unusual and greater number of wildlife sightings in urbanized areas mean for wildlife behaviour and wildlife conservation as a whole?

Fox kits on the boardwalk of Woodbine beach in the city of Toronto, Canada.4

The “rolling lockdowns” implemented as strategies to contain the novel coronavirus have severely restricted human activities, and have had cascading effects through public health systems and economies.6 What is less clear however, is what impacts this sudden change in human behaviour may have on wildlife and what the long-term implications are for the fate of wildlife conservation across the globe and into the future. The interaction between our societal response to COVID-19 and wildlife is a novel and emerging topic that scientists have only just begun to investigate. Unsurprisingly, initial findings tell a complex story, where lockdowns have had both positive and negative impacts on wildlife and the conservation of biodiversity.1,5,6

Initial positive effects of lockdowns on the environment, in general, include reductions in industrial activities and manufacturing, and restrictions on the transport of natural resources, leading to a decrease in global emissions and an increase in air and water quality.1,5 Other studies report decreases in noise pollution leading to an increase in sightings of animals in cities and harbours, along with reduced numbers of animals being killed by ships in waterways and by vehicles on roads.1,6 Similarly, a study conducted in Italy, the first country to implement a lockdown, found a greater proportion of sightings of species such as the crested porcupine in suburban and urban areas in 2020 compared to previous years.6 The same study also found evidence for an increase in the abundance and breeding success of certain species of birds during lockdown in urban areas, likely due to general decrease in the presence of humans.6

A crucial point to consider about all of these positive observed effects is that many of these effects, such as the presence of uncommon animals in urban areas, are likely to only be temporary and prone to reversal once restrictions are lifted and humans begin to revert back to pre-lockdown behaviours.5,6 It is also worth noting that many observed increases in animal numbers under lockdown conditions could have resulted from an increase in observation effort with more people participating in hobbies such as birding due to restrictions on other activities during lockdowns.6 Similarly, the greater detection of bird species could have been attributed to an increase in detection rates because of a reduction of background traffic noise with less traffic volume in lockdown conditions.6

There is great concern that the COVID-19 pandemic will severely hinder efforts to conserve biodiversity in the present as well as in the long term.6 During lockdown, there have been substantial delays in both species at risk management efforts and invasive species control programs,6 reduced funding available for conservation because of overstressed economies, reductions in wildlife-based tourism due to travel restrictions, and governmental capacity generally being prioritized for COVID-19 relief measures.1,5 The pandemic has undoubtedly put a strain on our capacity for conservation, and many initiatives will be playing catch-up to make up for precious lost time, where many of these conservation efforts are focused on species that are already teetering on the brink.

Increased human threats to nature are also expected to occur as a result of the lockdowns.5,6 As more people, especially in rural areas, are forced to navigate pandemic-driven economic downturns, they may have no choice but to turn to protected areas for resources.5 In addition to this, the reduced funding available for hiring patrol staff such as park rangers in protected areas can result in a lower likelihood of detecting poachers and can lead to an increase in illegal killing of wildlife, which has been the pattern already observed in multiple places across the globe including Europe, Africa, and Asia.1,5,6

Schematic of the potential impacts of the COVID-19 pandemic on different areas related to the conservation of wildlife in Africa, with the arrows indicating the directionality of these impacts.5

The surge of research examining the interaction between societal response to COVID-19 and wildlife tells a complex story.6 Although there were some positive effects of the lockdown observed on wildlife, these will likely only be temporary until restrictions are lifted, but the potential negative impacts could have long-lasting effects on the conservation of biodiversity.5,6 Furthermore, activities focused on the conservation of species and habitats can also help to reduce the risk of future pandemics as the restrictions put in place to protect certain species and their habitats can help to reduce our exposure to species that are a high risk for virus transfer to humans, leading to a lower risk of future outbreaks and subsequent pandemics.5

Overall, although the COVID-19 lockdowns have shown some initial positive impacts on the environment and wildlife, there are significant risks associated with these lockdowns that may negatively impact the effectiveness of wildlife conservation. In order to effectively prevent the accelerated loss of biodiversity that could result from lockdowns, countries must ensure funding for conservation actions is not neglected.



  1. Bates, A. E., Primack, R. B., Moraga, P., & Duarte, C. M. (2020). COVID-19 pandemic and associated lockdown as a “Global Human Confinement Experiment” to investigate biodiversity conservation. Biological Conservation, 248, 108665. https://doi.org/10.1016/j.biocon.2020.108665
  2. Dhopade, P. (2020, July 7). The tale of Toronto’s boardwalk foxes. Retrieved from https://www.macleans.ca/society/environment/toronto-boardwalk-foxes-coronavirus-lockdown/  
  3. Furlong, C. (2020, April 5). A herd of Kashmir goats invaded a Welsh seaside resort after the coronavirus lockdown left the streets deserted. Wildlife take to the streets as people stay indoors. [Getty Images]. Retrieved October 26, 2020 from https://www.cbc.ca/news/world/photos-wildlife-animals-take-to-streets-as-people-take-shelter-indoors-1.5519538
  4. Lautens, R. (2020, July 7). A few of the young kits at Woodbine Beach in Toronto; when passersby began taking selfies with the animals, a local wildlife centre intervened. The tale of Toronto’s boardwalk foxes. [Image]. Retrieved October 23, 2020 from https://www.macleans.ca/society/environment/toronto-boardwalk-foxes-coronavirus-lockdown/
  5. Lindsey, P., Allan, J., Brehony, P., Dickman, A., Robson, A., Begg, C., Bhammar, H., Blanken, L., Breuer, T., Fitzgerald, K., Flyman, M., Gandiwa, P., Giva, N., Kaelo, D., Nampindo, S., Nyambe, N., Steiner, K., Parker, A., Roe, D., … Tyrrell, P. (2020). Conserving Africa’s wildlife and wildlands through the COVID-19 crisis and beyond. Nature Ecology & Evolution, 4(10), 1300–1310. https://doi.org/10.1038/s41559-020-1275-6
  6. Manenti, R., Mori, E., Di Canio, V., Mercurio, S., Picone, M., Caffi, M., Brambilla, M., Ficetola, G. F., & Rubolini, D. (2020). The good, the bad and the ugly of COVID-19 lockdown effects on wildlife conservation: Insights from the first European locked down country. Biological Conservation, 249, 108728. https://doi.org/10.1016/j.biocon.2020.108728
  7. Wildlife take to the streets as people stay indoors. (2020, April 5). Retrieved from https://www.cbc.ca/news/world/photos-wildlife-animals-take-to-streets-as-people-take-shelter-indoors-1.5519538