[OANNES Foro] Declining fish biodiversity in Peruvian Amazon affecting human nutrition

[Mario Cabrejos]

*Declining fish biodiversity in Peruvian Amazon affecting human nutrition*

by Liz Kimbrough <https://news.mongabay.com/by/liz-kimbrough-2/>

28 May 2021

https://news.mongabay.com/2021/05/declining-fish-biodiversity-in-peruvian-amazon-affecting-human-nutrition/?utm_source=Mongabay+Newsletter&utm_campaign=e9c1d7db22-Newsletter_2020_04_30_COPY_01&utm_medium=email&utm_term=0_940652e1f4-e9c1d7db22-77237718&mc_cid=e9c1d7db22&mc_eid=b698d4520b


As the biodiversity of freshwater fish declines, what does this mean for
human nutrition?


Declining fish diversity in the Loreto department of the Peruvian Amazon
could affect nutrition for many of the region’s 800,000 people, according
to new study published in the journal *Science Advances*
<https://advances.sciencemag.org/content/7/22/eabf9967.full>.


In Loreto, people eat fish at least once a day, or about 52 kilograms (115
pounds) of fish per year, and rely on fish as a major source of protein,
fatty acids and essential vitamins and minerals such as iron and calcium.


“If fish decline, the quality of the diet will decline,” the study’s senior
co-author, Shahid Naeem, director of Columbia University’s Earth Institute
Center for Environmental Sustainability told Columbia Climate School
<https://news.climate.columbia.edu/?p=91586&shareadraft=baba91586_60903e7d374f9>.
“Things are definitely declining now, and they could be on the path to
crashing eventually.”


[image: A fishmonger processes a dorado catfish (Brachyplatystoma
rousseauxii) in the Belén Market in Iquitos, Peru. This fish is long
distant migrant that is vulnerable to overfishing and dam development.
Photo by Sebastian Heilpern.]


To assess the region’s fish, researchers set out to the early morning
markets. The study’s lead author, then-Columbia Ph.D. student Sebastian
Heilpern, visited fishing docks and ports at 3:30 am, as well as two major
retail markets in the towns of Belén and Iquitos later in the morning. On
those morning excursions, Heilpern and another student bought a few samples
of every fish species they could find. In the end, they found 56 out of
around 60 of the region’s known food species.


“I like to imagine the field work going a bit like playing Pokemon Go,”
Heilpern told Mongabay. “Like any ecological community, catches are
dominated by a handful of species and then have a long tail of rare ones,
and it quickly came down to getting those rare ones.”


After making his morning purchases, Heilpern shipped the fish on ice to a
lab in Lima, Peru where the tissues were analyzed for protein, fat, and
minerals. This data was compared to the probability of that species
surviving ongoing environmental degradation. The researchers then ran
scenarios of how people’s diets would be affected by the loss of specific
fish species.


In Loreto, fishers have been catching less large migratory fish species,
which are being replaced by smaller fish. Although protein levels are
roughly the same, smaller fish contain more omega-3 fatty acids but less
iron and zinc, overall—an issue in a region where people already have high
rates of anemia and malnutrition.


[image:
https://imgs.mongabay.com/wp-content/uploads/sites/20/2021/05/28023327/Community-Landing-scaled.jpg]A
fisherman pre-processes fish with help from a local boy before selling his
catch in a community along the Ucayali river in Loreto Peru.  The boy is
holding a boquichico (Prochilodus nigricans), a common but declining
migratory fish species.


This begs the question, why can’t people just eat different foods? Inland
communities are already transitioning toward eating more farmed fish and
chicken, but these foods may not be an adequate replacement for the range
of nutrients these communities get from a diverse diet of wild fish.


In another recent study <https://www.nature.com/articles/s43016-021-00242-8>,
Heilpern and colleagues found that farmed substitutions can undermine human
nutrition, exacerbating iron deficiencies and limiting essential fatty acid
supplies. Farming is also harder on the environment, requiring more energy
input and generating pollution in a system that is already stressed.
Additionally, farmed fish and chicken may cost more.


“Inland fish are fundamental for nutrition in many low-income and
food-deficit countries, and of course landlocked countries,” John Valbo
Jørgensen, an expert on inland fisheries with the UN Food and Agriculture
Organization told Columbia Climate School
<https://news.climate.columbia.edu/?p=91586&shareadraft=baba91586_60903e7d374f9>.
“Many significant inland fisheries, including those of Peru, take place in
remote areas with poor infrastructure and limited inputs. It will not be
feasible to replace those fisheries with farmed animals including fish.”


[image: A landing representing one night's fishing effort in the Tamshiyacu
Tahuayo Regional Conservation Area in Loreto, Peru. From left to right,
species are: palometa (Characiformes: Mylossoma duriventre), doncella
(Siluriformes: Pseudoplatystoma fasciatum), three boquichicos
(Characiformes: Prochilodus nigricans), palometa, two sardinas
(Characiformes: Triportheus sp.) and fasaco (Characiformes: Hoplias
malabricus). The ruler is in centimeters. Photo by Sebastian Heilpern]


“I think the main, big-picture message from the paper is how critical
diversity in our food supply is for delivering the range of nutrients
required for a healthy diet,” said Ruth DeFries, a professor at Columbia
University and one of the authors of the study in *Science Advances* told
Mongabay. And that diversity is under threat.


According to the World Wildlife Fund, one-third of global freshwater fish
species are threatened with extinction
<https://wwf.panda.org/discover/our_focus/freshwater_practice/the_world_s_forgotten_fishes/>,
and 80 species are already known to be extinct, Kevin Krajick reports
for Columbia
Climate School
<https://news.climate.columbia.edu/?p=91586&shareadraft=baba91586_60903e7d374f9>
.


Freshwater biodiversity is threatened by overfishing; dam development,
which blocks the passage of large, migratory species; deforestation; and
pollution from sources such as agriculture, urbanization, and mining. “Add
onto these factors climate change,” Heilpern told Mongabay, “and you have a
system that, barring major changes, will be stressed.”


Preserving biodiversity is not only a goal of conservation, Heilpern notes,
“but also a means towards sustainable fisheries and food
security…Conserving freshwater biodiversity can help achieve aquatic food
production and maintain nutrient supplies in places where people are highly
dependent on them.”


Ultimately, the researchers say, protecting fisheries will require
investing in practices and policies that protect key freshwater habitats,
maintain the connectivity of rivers and streams and enact temporary
moratoriums on the capture of overharvested species.


*A passenger and cargo-carrying ferry is docked in the port of Iquitos,
along the Amazon River. These ferries are the main conduits bringing fish
from distant locations in the region and supplying much of the ciy of
Iquitios. Photo by Sebastian Heilpern*.


Although the study in *Science Advances*
<https://advances.sciencemag.org/content/7/22/eabf9967.full> focused on
regional fish, other wild foods such as plants, insects, and bushmeat are
also an important source of nutrition across the globe, particularly for
Indigenous, rural, and low-income urban people.


“Regulations and public health policies need to consider biodiversity’s
vital role in sustaining nutritional benefits for over 2 billion people
dependent on wild foods across the globe,” the authors write. “Biodiversity
is notably absent from global and regional policies linking wild foods with
food security.”


“Only when biodiversity is valued alongside harvested biomass and revenue
will people be able to secure and sustain the full set of nutritional
benefits provided by wild foods.”


*Citation:*

Heilpern, S., DeFries, R., Fiorella, K., Flecker, A., Sethi, S.A., Uriarte,
M., Naeem, S. (2021). Declining diversity of wild-caught species puts
dietary nutrient supplies at risk. *Science Advances*, 7: eabf9967. DOI:
10.1126/sciadv.abf9967
<https://advances.sciencemag.org/content/7/22/eabf9967.full>

*Banner image** of boy and fish on the Ucayali River in Loreto Peru by
Sebastian Heilpern.*

*Liz Kimbrough** is a staff writer for Mongabay. Find her on Twitter: *
*@lizkimbrough_* <https://twitter.com/lizkimbrough_>

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