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
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
2. Mann, G. R. Tucuxi Dolphin. 2019
3. Operation Wallacea. Conservation
Research Expeditions. https://www.opwall.com/ (2020).
4. PROMPERU. Pacaya Samiria Nature 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.
8. da Silva, V. et al. Inia geoffrensis.
The IUCN Red List of Threatened Species 2018: e.T10831A50358152.
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,
10. Maugeri, S. fishing with bottom gillnets. FOOD
AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS FAO
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
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
15. Mongabay - EcoWatch. Brazil’s Amazon River
Dolphin Faces Extinction After Fishing Moratorium Ends.