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"Pig in a poke (gato por liebre)": The "mota" (Calophysus macropterus) Fishery, Molecular Evidence of Commercialization in Colombia and Toxicological Analyses


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Overfishing has affected the population abundance trends of many commercial fish species. In the Amazon, the fishery of a catfish commonly known as "mota" or "piracatinga" (Calophysus macropterus) has become an important economic activity in the region as this species has replaced a number of other overexploited great catfish species in the markets. Due to this high exploitation, ways in which to increase captures have been identified. One strategy is to use decomposing animal carcasses as bait. Such strategy has increased the hunting pressure on endangered species such as caimans and river dolphins. We investigated which catfish species are currently commercialized in Colombian fish markets using DNA barcoding, and measured mercury concentration in the tissues of fish molecularly identified as C. macropterus. We collected 86 fish samples in markets of four Colombian cities. Sixty-eight of these were identified molecularly as C.macropterus. The mercury concentration of 29 such samples was analyzed. Samples presented total Hg concentrations higher than the limit for human consumption established by the WHO (0.5 μg/g). These results are worrisome and suggest that (1) C. macropterus is a widely used fish species for human consumption in Colombia and (2) C. macropterus has high concentrations of total Hg, making its consumption a public health risk. Results presented here suggest that C. macropterus has replaced capaz in most Colombian markets. This fishery threatens wild species of river dolphins and caimans, and is also a public health risk given the high mercury levels we found in a subsample of these fishes.
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‘‘Pig in a poke (gato por liebre)’’: The ‘‘mota’’ (Calophysus
macropterus) Fishery, Molecular Evidence
of Commercialization in Colombia and Toxicological Analyses
Cristian Salinas,
Juan Camilo Cubillos,
Rigoberto Go
Fernando Trujillo,
and Susana Caballero
Laboratorio de Ecologı
´a Molecular de Vertebrados Acua
´ticos-LEMVA, Biological Sciences Department, Universidad de los Andes,
Carrera 1 No. 18A-10, Bogota
´, Colombia
Chemistry Department, Universidad de los Andes, Carrera 1 No. 18A-10, Bogota
´, Colombia
´n Omacha, Calle 86A No. 23-38, Bogota
´, Colombia
Abstract: Overfishing has affected the population abundance trends of many commercial fish species. In the
Amazon, the fishery of a catfish commonly known as ‘‘mota’’ or ‘‘piracatinga’’ (Calophysus macropterus) has
become an important economic activity in the region as this species has replaced a number of other over-
exploited great catfish species in the markets. Due to this high exploitation, ways in which to increase captures
have been identified. One strategy is to use decomposing animal carcasses as bait. Such strategy has increased
the hunting pressure on endangered species such as caimans and river dolphins. We investigated which catfish
species are currently commercialized in Colombian fish markets using DNA barcoding, and measured mercury
concentration in the tissues of fish molecularly identified as C. macropterus. We collected 86 fish samples in
markets of four Colombian cities. Sixty-eight of these were identified molecularly as C.macropterus. The
mercury concentration of 29 such samples was analyzed. Samples presented total Hg concentrations higher
than the limit for human consumption established by the WHO (0.5 lg/g). These results are worrisome and
suggest that (1) C. macropterus is a widely used fish species for human consumption in Colombia and (2) C.
macropterus has high concentrations of total Hg, making its consumption a public health risk. Results pre-
sented here suggest that C. macropterus has replaced capaz in most Colombian markets. This fishery threatens
wild species of river dolphins and caimans, and is also a public health risk given the high mercury levels we
found in a subsample of these fishes.
Keywords: Calophysus macropterus, DNA barcoding, total mercury, Colombia, Inia geoffrensis
The worldwide problem of overfishing has affected the
population abundance trends of many commercial fish
(Pauly et al. 2002). For this reason, there is a constant need
to find new species to replace commercially important
species in the market which are now scarce and sometimes
Electronic supplementary material: The online version of this article (doi:
10.1007/s10393-013-0893-8) contains supplementary material, which is available to
authorized users.
Cristian Salinas and Juan Camilo Cubillos share first authorship on this manuscript.
Published online: January 14, 2014
Correspondence to: Susana Caballero, e-mail:
EcoHealth 11, 197–206, 2014
DOI: 10.1007/s10393-013-0893-8
Original Contribution
2013 International Association for Ecology and Health
endangered (Myers and Worm 2003). This problem is
common in the Amazon, where the fishery of a catfish
commonly known as ‘‘mota’’ (Colombia), ‘‘simi’’ (Peru) or
‘‘piracatinga’’ (Brazil) (Calophysus macropterus, Lichten-
stein, 1819) has become an important economic activity in
the region and this species has replaced a number of other
overexploited large catfish species from the Amazon and
other rivers, including the Magdalena River in Colombia
(Petrere et al. 2004).
The use of this particular species to fill the market
niche previously occupied by the large catfish species from
the Amazon and the Magdalena is partly due to the fact
that this species is included in the Pimelodidae family,
where the large catfish species for human consumption
have also been classified, with around 40 species (Bogota
Gregory and Maldonado-Ocampo 2006). This is due to the
fact that catfish from this family may be similar in size and
they may look alike. Also, the widespread distribution of C.
macropterus in the Amazon region (Salinas and Agudelo
2000) increases the chance for its capture in ‘‘black’’ and
‘‘white’’ water rivers (these river names depend on the
amount of sediments, tannins, and pH characteristics of
rivers in the Amazon region) (Saint-Paul et al. 2000).
This widespread distribution may be partly the result
of its ecological role, as it is considered a scavenger Pe
and Fabre
´(2009). For this reason, it is frequently found
close to human settlements, feeding on animal remains
(Salinas and Agudelo 2000). C. macropterus has an average
size of 20.5 cm in length and an average weight of 300 g
(Carvalho et al. 2009). Because of its size, it is an ‘‘ideal’’
species to exploit for high demand for fish. The fisheries
effort for this species is around 627.43 tons per month in
Southern Amazonia (mostly in Brazil), making it one of the
most exploited catfish of the whole Amazonian region
(Alonso et al. 2007). Due to this high exploitation, several
methods to increase captures have been identified. One of
these strategies has been expanding the capture range to
include the Peruvian (Ortega et al. 2001), Brazilian
(Carvalho et al. 2009), and Colombian Amazon (Ortiz-
Zuluaga et al. 2006), including rivers such as the Putumayo
(Colombia) (Gonza
´lez et al. 2006) and also the low ‘‘Lla-
nos’’ of Venezuela (Castillo 1996). A second strategy,
considering low capture rates in some regions, is to use
decomposing animal carcasses as bait to attract this fish
(Trujillo et al. 2007).
The latest strategy has now increased the hunting
pressure on species such as caimans (Melanosuchus niger
and Caiman crocodilus) and river dolphins (Inia geoffrensis
y Sotalia fluviatilis), because its flesh is used as bait for C.
macropterus (Estupin
˜an et al. 2003; Silveira and Viana 2003;
Trujillo et al. 2007). Hunting these animals is relatively easy
and there is a market for this bait in some Amazonian
regions (Herna
´ndez-Rangel 2010). This hunting pressure
increases exploitation of these endangered species. It has
been estimated that around 1,500 dolphins are killed each
year to support this fishing practice (da Silva et al. 2008).
Currently, there are no available abundance estimates for
river dolphins in their whole distribution in the Amazon
and Orinoco basins, so it is unclear what percentage of the
total river dolphin population is being affected by this
fishing practice. Surveys along the main Amazonian and
Orinoco tributaries have been developed since 2006 in
order to determine their current abundance in most of
their distribution (Trujillo et al. 2010). For caimans,
available information suggests that around 150 tons of bait
were used in this fishery in 2001 (Silveira and Viana 2003).
In general, dolphin meat has been used for bait in
several places around the world including Chile (Goodall
and Jordan 1986) and Peru, where dolphin and porpoise
meat is used as bait in shark fisheries (Mangel et al. 2010).
This meat has two desirable characteristics for use as bait,
increasing its preference over other types of bait such as
caiman meat or cattle viscera for C. macropterus fishery.
First, the meat is very rich in fat, something that appears to
attract this fish and second, the strong odor that this meat
emits when decomposing attracts fish to a particular fishing
location in a short time (Estupin
˜an et al. 2003). Fishermen
targeting other fish species perceive dolphins as competi-
tors; therefore, they hunt them and sell them to C. macr-
opterus fishermen to use their meat as bait (Loch et al.
The commercialization chain of C.macropterus has
been identified as follows: the fish is obtained along the
Amazon River and some of its main tributaries, including
the Purus, Javari, and Ucayali Rivers. Then, from particular
localities or cities along the river, it is shipped to main
cities. For example, in Brazil, Manaus has been identified as
the main provider to markets in Sao Paulo and Rio de
Janeiro. In Colombia, fishermen bring their catch to a
centralized location in Leticia, from there it is shipped and
distributed mainly to Bogota
´and other main cities (Pe
and Fabre
´2009). Commercialization in cities far away from
the Amazon region can be attributed to the fact that C.
macropterus is considered a low-valued species in Amazo-
nian villages and cities due to its scavenger feeding habits
(Petrere et al. 2004).
198 Cristian Salinas et al.
Regarding its position in the food chain, C.macropterus
can be considered an interesting model organism to study
the levels of mercury exposure at the upper levels of
Amazonian food chains or scavenger organisms that feed
on top predator remains in the region. Also, since C.
macropterus is found scavenging close to human settle-
ments, it may be more exposed to runoff and pollutants.
The Amazon Basin has high natural sources of mercury due
to natural biogeochemical processes (Lechler et al. 2000).
However, due to increasing mining activities (Uryu et al.
2001), particularly artisanal mining, and the change of land
use in the Amazonian region (Lacerda et al. 2004), high
amounts of mercury have leached into the river. This free
inorganic mercury is then converted into organic mercury
forms, such as methyl-mercury that is then bioaccumulated
(accumulates in particular tissues) and biomagnified (in-
creases its concentration) along Amazonian food webs.
These processes represent a toxicological risk for full eco-
systems (Dudgeon et al. 2006; Dorea et al. 2006; Porto et al.
2005; Lailson-Brito Jr. et al. 2008; Cubillos 2009). It is to be
expected that this fish bioaccumulates mercury in high
levels, particularly if it feed on the remains of top predators
such as caimans and river dolphins, animals that have been
shown to concentrate mercury in high levels in their tissues
´ndez-Rangel 2010; Silveira and Viana 2003; Gutleb
et al. 1997; Dove 2009) and in their milk (Rosas and Lehti
1996). For this reason, measuring and monitoring mercury
concentrations in this fish are important considering the
pervasive effects mercury has on human and animal health,
including its neurotoxicity (Malm et al. 1995; Castilhos
et al. 1998; Dove 2009).
In Colombia, there was some information suggesting
that C. macropterus was being commercialized as another
species, the ‘‘capaz’’ from the Magdalena River (Pimelodus
grosskopfii) in the big supermarket chains and also in the
main central markets in Bogota
´and other cities. For this
reason, the aims of this study were: (1) to indentify via
‘‘DNA barcoding,’’ which species of freshwater catfish were
commercialized in Colombian markets, particularly in
´and (2) to determine the levels of mercury con-
centrations in commercialized C. macropterus.
DNA barcoding, a molecular technique based on
sequencing a portion of the mitochondrial DNA cyto-
chrome oxidase I (COI), has been widely used to identify
species and parts of species that may be legally or illegally
traded, including fish species being traded as a different one
in order to increase its price and availability in the market
(Baker 2008). DNA barcodes have allowed identification of
species sold as snapper in a number of markets in the USA
and also to identify tuna and other fish species used in sushi
preparations (Stokstad 2010; Wong et al. 2011). In addi-
tion, the use of DNA barcodes has allowed an under-
standing of the trading tendencies of shark fins in Asian
markets, as well as providing a tool for species trade
monitoring (Abercrombie et al. 2005; Clarke et al. 2006).
DNA barcoding may help to establish the geographical
origin of a particular sample, and also commercialization
or trade routes, in addition to being useful in under-
standing how a particular market or fishery works.
Fish Sampling
Eighty-sixfish specimens were obtainedfrom different sources
(fishermen, distributors, and markets) in eight locations in
Colombia between June and October 2010. Forty-six of these
samples where obtained from ‘‘source’’ localities (a source,
defined as places where the fishing activity is done or where
fishermen bring their catch to be commercialized), and these
samples were morphologically identified using identification
guides and species identification was confirmed by taxonomic
experts in the field. These specimens were also molecularly
identified in order to use them for comparison in further
analyses. These specimens were obtained in the Colombian
Amazon (PuertoNarin
˜o and Leticia), the Colombian Orinoco
(Inirida), Meta Province (Puerto Lo
´pez), and Putumayo
Province (Puerto Ası
´s) (Fig. 1).
Forty specimens were obtained from markets in Bo-
´, Girardot, and Melgar, where they were sold as ‘‘ca-
paz’’ from the Magdalena River. The latest two cities are
located on the Magdalena River, about 98 km southwest
from Bogota
´. They all were sold at different prices and all
were sold under the name ‘‘capaz.’’ A small tissue sample
from each specimen was cut and transferred to 70% etha-
nol and refrigerated at 4C.
DNA Extraction, Amplification, and Phylogenetic
DNA was extracted from tissue samples following a phe-
nol–chloroform protocol from (Sambrook et al. 1989)
modified for small samples by (Baker et al. 1994).
Approximately 558 base pairs (bp) of the mitochondrial
COI gene were amplified via PCR, using the primers
COXFISH F1-R1 (Ward et al. 2005). Bioline Taq Poly-
Pig in a poke (gato por liebre) 199
merase was used and the temperature profile was as follows:
an initial denaturation for 2 min at 94C, followed by 35
cycles at 94C for 30 s, annealing at 59C for 45 s, elon-
gation at 72C for 1 min 20 s, and a final extension 72C
for 15 min. PCR products were run and visualized in a
1.5% agarose gel stained with ethidium bromide. Successful
amplification products were purified via a protocol using a
polyethilenglycol resin and a final wash with 96% ethanol
and sequenced, following the Sanger methodology, on an
ABI3100 at Macrogen Korea.
COI sequences were manually edited and aligned with
previously published COI sequences from different species
from the family Pimelodidae available from GenBank
( (for accession numbers see Sup-
plementary Material Table 1) using the software Geneious
version 5.3.3 (Biomatters Ltd). This dataset was further
used for phylogenetic reconstructions using Neighbor-
Joining (NJ) in PAUP (Swofford 2011). These reconstruc-
tions are considered the standard for DNA barcoding
methodology and species identification in a wide variety of
Figure 1. Sample localities: Putu-
mayo River Basin—1Puerto Ası
Putumayo Province (four sam-
ples). Magdalena River Basin—2
Girardot, Cundinamarca Province
(four samples), 3Melgar, Tolima
Province (five Samples), 4Bogota
Cundinamarca Province (31 sam-
ples). Meta River Basin—5Puerto
´pez, Meta Province. Amazon
River Basin 6Puerto Narin
˜o, 7
Leticia, Amazonas Province (33
samples) and Orinoco River Re-
gion—8Puerto Inı
´rida, Guainı
Province (seven samples).
200 Cristian Salinas et al.
taxa (Hebert et al. 2004; Hellberg and Morrissey 2011; Ross
et al. 2003).
Total Mercury Analyses
From the total of 86 specimens collected in this study, a subset
of 29 frozen samples from specimens molecularly identified as
C. macropterus were included in this analyses. Antero-dorsal
muscle samples were collected and acid-digested following the
protocols described by Sadiq et al. (1991). Total mercury
) concentrations were determined by cold vapor
atomic absorption spectroscopy in a CV-AAS (Perkin-Elmer
AAnalyst 300). Analyses were carried out at the spectroscopy
laboratory of Universidad de los Andes, Bogota
Three replicates per sample (0.5 g of skinless and boneless
flesh) were considered to determine the precision and accu-
racy of Hg concentrations. A standard biological reference
material (DOLT-2 from NRCC Ottawa, Canada) was mea-
sured for calibration purposes and comparisons.
Once the values for mercury concentration were ob-
tained, the mean concentration of mercury was estimated
for each sample and then used for the estimation of the
bioaccumulation curves presented in Figure 3a, b . A two-
way ANOVA was performed in order to determine the
differences in mercury concentration among the localities
presented in this study (Fig. 4).
DNA Barcoding
A total of five different species were identified from the 86
specimens analyzed. Morphological identification made in
the field was confirmed by genetic analyses of 558 bp of the
COI gene. These five species were identified as belonging to
the family Pimelodidae with high similarity percentages
(85–95%) (Table 1). Only C. macropterus showed more
than one COI haplotype and the clade for this species was
supported with a bootstrap value of 100 (Fig. 2). COI se-
quences were also useful to identify the origin of specimens,
taking into consideration sequences from specimens col-
lected in field locations in the Colombian Amazon, Bra-
zilian Amazon, and Colombian Orinoco. In the NJ
reconstruction (Fig. 2), a clade-joining specimen from the
Amazon was clearly separated from specimens from the
Orinoco. C. macropterus is the species which is sold in
higher proportion in the Colombian markets and is studied
as if it was the capaz from the Magdalena River (P. gross-
kopfii), but there is evidence of other species also sold as if
they were capaz. Only three specimens obtained in the
markets in Melgar were identified as the real capaz from the
Magdalena (P. grosskopfii) (Table 1).
Total Mercury Analyses
All samples included in the mercury analyses were inden-
tified as C. macropterus. These samples had Hg
centrations higher than the maximum permissible limit of
0.5 lg/g (WHO 2007) established for human consumption.
The concentration values ranged from 1.33 to 2.28 lg/g.
concentrations compared to fish length and to fish
weight for all sampling sites (including locations of origin
and one market location) are shown in Figure 3a, b.
Analyses for Hg
by length showed that even small fish
(30 cm in length) presented values higher than values
recommended by the WHO. No clear correlation was
found between Hg
concentration and fish weight, with
some lighter fish having higher concentration than some of
Table 1. Summary of specimens analyzed in this study and the percentage of species representation in the sample of 86 specimens
analyzed in total (in bold).
Commercial name Local name Scientific name Number of specimens
Capaz (B)
Capaceta (B) (M) (G)
Mota, Piracatinga, Zamurito, Simi, Picalon,
Capaceta, Barbuchas, mapuro
Calophysus macropterus 78 (90.7%)
Capaz (B) Pirabuton, Blancopobre, Mapuro Brachyplatystoma vaillantii 3(3.5%)
Capaz (B) (M) (G) Capaz Pimelodus grosskopfi 3(3.5%)
Capaz (B) Barbancho, Barbichato, Piramutaba Pinirampus pinirampus 1(1.15%)
Capaz(B) Mapara
´Hypophthalmus marginatus 1(1.15%)
Commercial name refers to the name used for a particular species in the markets of Bogota
´(B), Girardot (G), and Melgar (M). Local name refers to the name
used for a particular species in the Colombian Amazon (Leticia, Puerto Narin
˜o, and Puerto Ası
´s), the Brazilian Amazon (Tabatinga), The Colombian Orinoco
(Puerto Lo
´pez and Puerto Inı
Pig in a poke (gato por liebre) 201
the heavier fish analyzed. The bioaccumulation tendency
was low according to the correlation coefficients. The
variation in Hg
concentration among locations is show
in Figure 4. For instance, Putumayo showed a higher
average of Hg
concentration (2.35 lg/g) compared to
other sampling locations such as Bogota
´, showing the
lowest average of Hg
concentration (1.73 lg/g). How-
ever, there were no significant differences among the
localities with regards to mercury concentrations (ANOVA
P= 0.247, Fig. 4).
In this study, we used multidisciplinary techniques to
evaluate which species of fish are currently used in the
Colombian market to replace the commonly known but
currently scarce and endangered capaz from the Magdalena
River. In addition, we measured mercury levels in a subset
of samples to determine if the consumption of C. macr-
opterus, commonly known as mota or capacete and found
in the Amazon and Orinoco, poses a risk to human health.
Cryptic species of fish, or those morphologically sim-
ilar, pose a challenge for the final consumer given their
inability to clearly identify which species they are pur-
chasing. An example is found in Colombia, where the final
consumer thinks they are purchasing capaz but instead they
are being sold C. macropterus or other species. This hap-
pens when the final consumer thinks they are buying capaz
from the Magdalena River but instead they are being sold
C. macropterus or other species. This is of concern for
several reasons. First, the C. macropterus fishery poses a risk
to the conservation of endangered river dolphins and cai-
mans, since fishermen use these species as bait. Second, as
we show here, the high concentrations of mercury in the
tissues of C. macropterus result in a serious health concern,
particularly in large cities where this fish is consumed in
large quantities. The problem of misleading the public into
consumption of particular species based on deceiving their
decision-making capacity is not unique for this case but has
been widely researched in a number of fisheries around the
world (Filonzi et al. 2010; Wong et al. 2011). For example,
in Brazil, researchers found that 80% of fish filets labeled as
surubim (Pseudoplatystoma spp.) were in reality other than
catfish species (Carvalho et al. 2011). Also, researchers in
New York found that red snapper (Lutjanus campechanus)
was the most commonly mislabeled fish in the market
(Wong and Hanner 2008).
Also, it is common to present the ‘‘substituted’’ fish as
fillets, in which case it is almost impossible to visually
identify the species of origin. Some vendors may also
scratch the side of the fish to remove the spots that allow
differentiating mota from capaz. For this reason, the use of
DNA barcodes to investigate what is sold in the market
provides a precise, fast, and powerful technique for
detecting this kind of fraudulent sale behavior (Galimberti
et al. 2013). Its application in market surveys or monitoring
to ensure quality of the product being sold can be greatly
increased (Holmes et al. 2009). Also, it can detect if
endangered species are commercialized illegally, as was the
recent case when sushi made with whale meat was detected
in a restaurant in the United States (Baker et al. 2010). In
our case, it confirmed the suspicions of replacement of
Pimelodus grosskopfii, capaz from the Magdalena River,
mostly by C. macropterus in markets of Colombia. Three
other fish species from the Pimelodidae family (Pinirampus
pinirampus,Brachyplatystoma vaillantii, and Hypophthal-
mus marginatus) were identified in this study, all being
commercialized, but in an apparently much smaller pro-
portion than C. macropterus. The use of other species to
replace the capaz may be due to fluctuations in its capture
at different times of the year (Go
´mez et al. 2008). All these
Figure 2. Neighbor-joining reconstruction based on COI gene
sequences. Bootstrap support values are on top of branches. Sequences
labeled with (asterisk) correspond to previously published sequences
available from GenBank.
202 Cristian Salinas et al.
species are found in the Amazon and Orinoco basins and
not in the Magdalena River.
Our results support recently published information by
the Colombian government (Ministerio de Agricultura y
Desarrollo Rural—MADR 2010), evidencing higher ex-
ports from C. macropterus originating from Colombia and
its increase in the internal market as well as decreased
numbers on capaz being commercialized in the country,
demonstrating population reductions for this species. The
capaz from the Magdalena River (Pimelodus grosskopfii) is
now classified as a vulnerable species in Colombia (Mojica
et al. 2012). The low availability of capaz from the
Magdalena has increased its market price. Currently, one
(1) pound of capaz costs about $6.25 USD, while the cost
of C. macropterus is about $2.5 USD per pound. The
considerable difference in price between mota and capaz
also resulted in markets preferring to sell the cheaper fish
at a higher cost.
Figure 3. a Bioaccumulation curve
(scatter-plot) of muscle-Hg con-
centrations as a function of body
length presented for all sampling
locations. bBioaccumulation curve
(scatter-plot) of muscle-Hg concen-
trations as a function of body
weight presented for all locations.
Figure 4. Box-plot of the variation in Hg
concentration from specimens among sampling
Pig in a poke (gato por liebre) 203
The final consumer is not capable of telling the two
species apart and is deceived when not informed properly
of what species they are buying. We conducted a small
number of surveys (15 to fish dealers and 20 to final con-
sumers) in the three cities included as the ‘‘market’’ in this
study (Bogota
´, Melgar, and Girardot). Results suggested
that fish dealers (fishermen, restaurant owners, and fish
dealers) were aware of the replacement of capaz by mota
and they successfully identified mota as capacete (see Ta-
ble 1). Final consumers were not aware of the replacement.
Also, it was clear that almost none selling or buying C.
macropterus was aware of the way in which these fish are
captured through the use of river dolphins and caimans as
bait (Alves et al. 2012;Go
´mez et al. 2008; Mintzer et al.
2013; da Silva et al. 2011). An unaware market may be the
cause of approximately 1,150 tons of C. macropterus being
obtained in the Brazilian Amazon each year (Trujillo et al.
2010), overexploiting this fish and causing a significant
decrease in numbers in the populations of the animals used
as bait. This was recently demonstrated for Inia geoffrensis
in the central Brazilian Amazon. In this study, researchers
in the Japura
´and Solimo
˜es Rivers used capture/recapture–
resighting data from marked Inia geoffrensis for a 17-year
period. They estimated that apparent survival of these
dolphins was significantly lower in the years following the
start, about 10 years ago, of the harvesting of these animals
for bait (Mintzer et al. 2013). There are no clear estimates
of how many caimans are killed each year in the Amazon
for bait, but data from 2001 suggested that approximately
150 tons of caimans were used in this fishery, considering
that for each kg of C. macropterus obtained, 1 kg of caiman
bait was used (Silveira and Viana 2003). Ganges river
dolphins (Platanista gangetica) were used as bait (Smith
et al. 1998) and their oil used as fish attractant (Sinha 2002)
in Bangladesh and India in the late 1990s. This caused
population numbers to crash and to this date remain in
very low numbers.
The total mercury concentrations in fish muscle found
in this study were much higher than the ones found in
previous studies in the Amazon region (Malm et al. 1995;
Cubillos 2009). These concentrations were even higher than
the recommended levels allowed for human consumption
by the WHO (0.5 lg/g). No significant differences were
found in mercury concentration among the capture local-
ities, which may suggest two possible models as a way to
explain the high concentrations detected in this study. First,
migratory organisms may be transporting organic mercury
from highly mercury-polluted locations to other regions.
Second, all the regions where samples were collected have
high mercury levels due to geological characteristics, arti-
sanal mining, or to the change in land use as has been
previously suggested by Lechler et al. (2000) and Lacerda
et al. (2004).
In this study, we demonstrated the reliability of DNA
barcoding for species identification and presented evidence
of commercialization of mercury-contaminated fish in
Colombian markets. We believe that regulation of this
fishery, including strong legislation making the use of river
dolphins and caimans as bait illegal, must be implemented
in all nations from the Amazon region, particularly Brazil,
Colombia, and Peru. It is necessary to track the origin and
fishing technique used in the capture of C. macropterus.
The use of cattle viscera represents fish bait alternatives and
it is being currently used in some areas of Colombia (Go
mez et al. 2008). For this reason, a chain of custody,
making clear which bait was used to capture C. macropterus
is necessary in order to allow the final consumer to make an
informed decision. A chain of custody in this context refers
to the tracking of a product from its origin and in every
stage of the supply chain to ensure the end consumers that
the product was obtained from a sustainable source or in
an environmentally sustainable way. Such chains of custody
have been developed for fisheries, as is the case for the
Marine Stewardship Council eco-labeled products (Gul-
brandsen 2009). Also, increased monitoring of fishing
practices and follow up of testing for mercury content is
also needed in order to determine if the trade and con-
sumption should be continued. We suggest that the gov-
ernmental entities working in collaboration with NGOs
and academic institutions should also provide alternatives
to the fishing communities regarding sustainable manage-
ment of aquatic resources and alternatives to the C.
macropterus fishery.
The authors want to thank all the people who in one way or
another helped in developing this study and in sample
collection. We would like to thank Luis Fernando Mejia,
Veronica, and Melany Villate for their collaboration in the
total mercury sample analyses. Funds for this project were
made available by Universidad de los Andes (proyecto
Profesor Asistente, Departamento de Ciencias Biolo
and Departamento de Quı
´mica), Cetacean Society Inter-
national, Whale and Dolphin Conservation Society, Whit-
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... Wildlife (mainly omnivorous and carnivorous species) is exposed to MeHg through their diet (Ullrich et al., 2001;Sarica et al., 2005;de Moura et al., 2012). Mercury bioaccumulation causes concentrations to increase greatly in top predators such as large catfish, black caiman, and mammals such as otters, and dolphins (Markert, 2007;Molina et al., 2010;Bossart, 2011;Salinas et al., 2013;Nuñez-Avellaneda et al., 2014;Mosquera-Guerra et al., 2015. Because many aquatic mammals are at the top of food chains, they are especially threatened by bioaccumulation of mercury (Brum et al., 2021) (Figure 20.14). ...
... Nuñez-Avellaneda et al. (2014) evaluated the presence of total mercury in muscle tissue samples of eleven fish species at four locations in the Colombian Amazon, reporting values that ranged between 0.0116 and 2.0123, mean = 0.3549 mg Hg kg -1 . Mosquera-Guerra et al. (2015) reported that 54% (n = 103) of the total tissue samples of the catfish species Calophysus macropterus (omnivore) from the Amazon had concentrations between 0.11 and 1.66 mg Hg kg -1 , coinciding with the findings of Salinas et al. (2013) for the same catfish species. However, elevated levels of mercury in fish can also occur naturally at locations far from human activities (Marshall et al., 2016). ...
Full-text available
This Report provides a comprehensive, objective, open, transparent, systematic, and rigorous scientific assessment of the state of the Amazon’s ecosystems, current trends, and their implications for the long-term well-being of the region, as well as opportunities and policy relevant options for conservation and sustainable development.
... Wildlife (mainly omnivorous and carnivorous species) is exposed to MeHg through their diet (Ullrich et al., 2001;Sarica et al., 2005;de Moura et al., 2012). Mercury bioaccumulation causes concentrations to increase greatly in top predators such as large catfish, black caiman, and mammals such as otters, and dolphins (Markert, 2007;Molina et al., 2010;Bossart, 2011;Salinas et al., 2013;Nuñez-Avellaneda et al., 2014;Mosquera-Guerra et al., 2015. Because many aquatic mammals are at the top of food chains, they are especially threatened by bioaccumulation of mercury (Brum et al., 2021) (Figure 20.14). ...
... Nuñez-Avellaneda et al. (2014) evaluated the presence of total mercury in muscle tissue samples of eleven fish species at four locations in the Colombian Amazon, reporting values that ranged between 0.0116 and 2.0123, mean = 0.3549 mg Hg kg -1 . Mosquera-Guerra et al. (2015) reported that 54% (n = 103) of the total tissue samples of the catfish species Calophysus macropterus (omnivore) from the Amazon had concentrations between 0.11 and 1.66 mg Hg kg -1 , coinciding with the findings of Salinas et al. (2013) for the same catfish species. However, elevated levels of mercury in fish can also occur naturally at locations far from human activities (Marshall et al., 2016). ...
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Amazon aquatic ecosystems are being destroyed and the threats to their integrity are projected to grow in number and intensity. In this chaper we review a number of these threats. Hydroelectric dams (n=307 existing or under construction) have changed almost every aspect of Amazon aquatic ecosystems, and many more dams are planned (n=239), posing threats to the region’s enormous aquatic biodiversity and fisheries resources. By blocking fish migrations dams affect important commercial species, as well as the flow of sediments and nutrients that sustain aquatic food chains and support fish populations. By altering stream flows and flooding regimes, dams and their reservoirs also disrupt downstream ecosystems, including flooded forests and the floodplain lakes that are essential for breeding of many fish species. The low-oxygen (anoxic) conditions found near reservoir bottoms cannot be tolerated by many fish species. They also favor the formation of highly toxic methylmercury and the production of methane, a powerful greenhouse gas. Small dams and reservoirs can have substantial impacts that are often even greater than large dams on a per-Megawatt (MW) or per-hectare basis. In Brazil the definition of “small” dams has pro- gressively increased from less than 10 to 30 to 50 MW, opening an expanding loophole in the environmen- tal licensing system. Overharvesting of fish for both food and the ornamental trade has depleted fish stocks and altered their ecological roles. Native species are threatened by invasive species that escape from aquaculture operations and potentially from proposed inter-basin river diversions. Deforestation changes chemical and physical properties of streams, including releasing natural deposits of heavy metals (such as mercury from erosion) and eliminating aquatic species that inhabit watercourses in Amazon for- est. Pollution sources include toxins from agriculture and industrial and urban waste, such as plastic, mercury, transition metals like Cu, Cd, Pb, Ni, etc., urban sewage, and various forms of toxic waste. Oil spills have had disastrous consequences in Ecuador and Peru. Gold mining releases large amounts of sed- iments, in addition to releasing mercury and provoking the clearing and degradation of floodplain forests. Roads contribute to the fragmentation of streams and river tributaries as well as generating sediments through soil erosion, in addition to the sediment from the deforestation that roads provoke. Navigational waterways cause multiple impacts on the rivers converted to this use, particularly affecting the reproduction habitats of freshwater species. Climate change impacts aquatic ecosystems through increased temperature and through extreme droughts and floods. Interactions among drivers mean many of these im- pacts are even more harmful to aquatic ecosystems. The authors of this chapter recommend that no more hydroelectric dams with installed capacity ≥ 10 MW should be built in Amazonia, that investments in new electricity generation should be redirected to wind and solar sources, and that all environmental assessments should incorporate synergistic and cumulative impacts in their analyses. In addition to the ecosystem impacts that are the subject of this chapter, the extraordinarily great social impacts of Amazonian dams (Chapter 14) lead to the same conclusion. Fortunately, countries like Brazil have abundant undeveloped wind and solar potential. Keywords: Climate change, dams, fish, invasive species, mercury, oil spills, pollution, river diversion, toxic waste, waterways
... This disparity, among other causes, has led to a pronounced incidence of fraud in the labeling of marine fish products, as has been reported in several studies (Cunha et al., 2015;Xiong et al., 2016;Pardo et al., 2018;Horreo et al., 2019;de Carvalho et al., 2020;Peterson et al., 2021). In Colombia, fish commercialization is controlled by the National Institute for the Vigilance of Drugs and Food (INVIMA), which establishes the use of taxonomic keys (macroscopic characteristics of the whole fish) as the identification protocol for commercial species (Salinas et al., 2014). This regulation presents two problems: the first being related to the incidence of fish identification errors due to physical similarities among some species and the second, to the transformation of the fish into different products (frozen fillets, breaded, precooked, etc.), which do not allow the use of the established identification protocol. ...
... Moreover, in Brazil a rate of 77% fraud was reported in the commercialization of croaker fish (Sciaenidae) (de Brito et al., 2015), and in Spain, Finland, Germany and Iceland, 50% of the analysed seafood samples were found to be sold under the wrong name (Pardo et al., 2018). In Colombia, only two studies have been published on the subject: firstly, Salinas et al. (2014) reported a drastic change in the catfish species sold as "capaz" (Pimelodidae family), as overfishing has led to the introduction of smaller, lesser known species, whose capture involves the killing of river dolphins and caimans to be used as bait. Secondly, Castaño (2015) reported 40% of fish mislabeling in the capital city Bogot a, finding that one out of three fillets sold as common snook belonged to the basa catfish (Pangasius sp). ...
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The common snook Centropomus undecimalis is one of the main commercial fish species in the Caribbean region, including Colombia, where its populations have drastically decreased due to overfishing and environmental degradation. Thus, there is a market imbalance between the availability of snook products and their demand by consumers, which creates an opening for fraudulent actions such as species substitutions. Legislation in Colombia (and most Caribbean countries) lacks effective tools for the easy and rapid detection of frauds. Furthermore, there are very few studies published in scientific journals addressing this issue, of which none include C. undecimalis as the target species. Therefore, in order to investigate the existence of mislabeling in common snook products in Santa Marta, the present study analysed 44 frozen snook fillets from the five commercial brands available in the city. Moreover, 15 fresh snook fillets from six of the main fish markets were also analysed. To discover the frequency of possible frauds in labeling, samplings were carried out in July, September and November of 2019. Sample analyses involved the identification of each fillet at species level through molecular barcodes (16S-rRNA and COI), whose sequences were verified using BLAST and BOLD, and corroborated by a phylogenetic analysis. As a result, an astonishing 98% of the supermarkets fillets were found to be fraudulent, contrasting with a single case registered in the fish shop samples. The species used to substitute snook include the Pacific bearded brotula Brotula clarkae (38 samples), the Nile perch Lates niloticus (4 samples) and the acoupa weakfish Cynoscion acoupa (1 sample). Based on these results, there is a high rate of fraudulent labeling in the marketing of common snook in the city of Santa Marta, which calls for urgent actions to be taken by the corresponding authorities.
... have been hunted illegally for their meat to use as bait for fishing the scavenger catfish Calophysus macropterus (known as blanquillo in Bolivia, piracatinga or douradinha in Brazil, mota or zamurito in Colombia and Ecuador, simi or mota punteada in Peru, and mapurite in Venezuela; Flores et al., 2008;Trujillo et al., 2010;Alves et al., 2012;Cosentino and Fisher, 2016;. This catfish largely replaces either explicitly or implicitly the overfished Pimelodus grosskopfii, or capaz distributed in the Magdalena-Cauca basin in Colombia (Goḿez et al., 2008;Salinas et al., 2014;Mosquera-Guerra et al., 2015); and its trading has spread to domestic markets in Brazil (Cunha et al., 2015), and Venezuela (Diniz, 2011). ...
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Unsustainable fisheries practices carried out in large parts of the Amazon, Tocantins, and Orinoco basins have contributed to the decline in the populations of the Amazon River dolphins (Inia spp.), considered Endangered by the International Union for Conservation of Nature (IUCN). Amazon River dolphin byproducts are often obtained through unregulated fisheries and from stranded and incidentally caught individuals that are traded for the flesh and blubber used for Calophysus macropterus fisheries, traditional and other medicinal purposes, and more recently for human consumption. To identify localities of use of Amazon River dolphins, we conducted a systematic review of the related literature published since 1980, complemented with structured surveys of researchers that allowed the identification of 57 localities for uses of Inia (33 in the Amazon, two in the Tocantins, and 22 in the Orinoco basins), and two more on the Brazilian Atlantic coast, with recent reports of targeted consumption in the upper Orinoco River. Subsequently, the localities of use or bushmeat markets where Amazon River dolphin byproducts are trafficked were identified. This information was integrated with a kernel density analysis of the distribution of the Inia spp. populations establishing core areas. Our spatial analysis indicated that the use of Inia spp. is geographically widespread in the evaluated basins. It is urgent that decision-makers direct policies towards mitigating the socioeconomic and cultural circumstances associated with illegal practices affecting Amazon River dolphin populations in South America. Keywords: amazon basin, Inia spp, artisanal fisheries, conservation, fishery-dolphin interactions, intentional catches, orinoco basin, tocantins basin
... Otros estudios se han enfocado particularmente en la especie Calophysus macropterus. Salinas et al. (2014) analizo 29 muestras de esta especie provenientes de pescadores, distribuidores y de mercados en ocho localidades en Colombia, entre ellos Puerto Asís, Puerto Nariño y Leticia de la Amazonía. Se encontraron concentraciones de mercurio de 1,3 a 2,3 ppm. ...
... En ictiología, las aplicaciones de genética poblacional incluyen mapeo genético e identificación de genes para susceptibilidad a enfermedades, tamizaje poblacional para portadores de enfermedades genéticas, análisis de varios genes que especifican rasgos cuantitativos (QTL), diversidad genética y estructura poblacional. Esta información es utilizada para el manejo pesquero, requerimientos de trazabilidad en el mercado de peces y productos ícticos (Salinas et al. 2014), identificación de especies crípticas (Ríos et al. 2017), programas de reproducción (Hashimoto et al. 2010(Hashimoto et al. , 2011, identificación de escapes en acuicultura (Bignotto et al. 2009, Prado IAvH et al. 2012, 2017 y reforzamiento/repoblamiento de poblaciones naturales (Cardoso de Carvalho et al. 2013, Casey et al. 2016, Dantas et al. 2013, Ovenden et al. 2015. ...
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El conocimiento de la diversidad genética y la estructura poblacional son fundamentales para mejorar el manejo y conservación de los peces. La cuenca del Magdalena se destaca por una alta riqueza íctica que se aprovecha como recurso pesquero y acuícola, la cual contrasta con la cantidad de estudios de genética poblacional de su ictiofauna. Una revisión permitió identificar estudios genético-poblacionales en 14 especies nativas y dos exóticas, y en la última década, el desarrollo de loci microsatélites publicados para 13 de 17 especies. En general, la diversidad genética es alta para los “stocks” naturales de especies de interés pesquero; sin embargo, los coeficientes de endogamia también son altos en el bocachico (Prochilodus magdalenae); el capaz (Pimelodus grosskopfii) y el barbudo (Pimelodus yuma). La mayoría de las especies de peces muestran flujo genico de uno o varios grupos genéticos que cohabitan en la misma área, excepto en algunos casos donde exhiben estructura genética a escalas geográficas locales (la sabaleta, Brycon henni) o regionales (B. henni, P. grosskopfii y P. yuma). además, se desconocen los impactos ecológicos, genéticos y sanitarios de los repoblamientos y la introducción de especies exóticas en la ictiofauna nativa. La falta de datos históricos no permite evidenciar la perdida de diversidad genética; y la ausencia de marcadores moleculares o inconsistencia en su uso, limitan las comparaciones entre los pocos estudios genéticos poblacionales publicados. Se discute la relevancia de continuar el desarrollo de loci de microsatélites específicos para las especies, principalmente las de mayor interés en las pesquerías y desarrollo acuícola. Esto puede brindar una oportunidad a corto plazo para evaluar el estado general de las especies de peces a una escala nacional y la pertinencia de replantear los programas de repoblamiento. **** Knowledge of genetic diversity and population structure are essential to improve the management and conservation of fish stocks. The Magdalena-Cauca River basin stands out for its high fish species richness and abundance used both as a fishery and an aquaculture resource, which contrasts with the number of population genetic studies of its ichthyofauna. Our review found population-genetics studies for 14 native and two exotic commercial species, and microsatellite loci have been published for 13 of 17 species. In general, the genetic diversity of fish is high for the “natural stocks” of species of fishing interest, however, the inbreeding coefficients are high in some species such as the bocachico Prochilodus magdalenae, the capaz Pimelodus grosskopfii and the barbudo Pimelodus yuma. Most fish species show gene flow from one or more genetic groups that coexist in the same area, except in some cases where they exhibit genetic structure at the local (sabaleta, Brycon henni) or regional level (B. henni, P. grosskopfii and P. yuma). In addition, the ecological, genetic and health impacts of the fish stock repopulations and the introduction of exotic and/or transplanted species in the native ichthyofauna are unknown. The lack of historical data does not allow analysis of the possible loss of genetic diversity and the absence of molecular markers or inconsistency in their use limits the comparisons between the few population genetic studies published. The need for continuing the development of specific microsatellite loci for species of greatest interest in fisheries and aquaculture development is discussed. This would provide a short-term opportunity to assess the general status of fish species on a national scale and the need for rethinking stocking programs.
... Using river dolphins as bait is illegal in Peru and we suspect that some of the participants feared legal repercussions if they confirmed the use of these protected species in their fishing communities. The use of river dolphins as bait is consistent with reports from other countries in the region, including Colombia and Brazil, where Inia and caimans have been reported as used as bait in the piracatinga fishery over the last decade (Cunha et al., 2015;Mosquera-Guerra & Trujillo, 2015;Salinas, Cubillos, Gómez, Trujillo, & Caballero, 2014). Mintzer et al. (2015) found that 98% of interviewed fishers knew of the use of dolphins as bait, and 67% of them could identify at least one community, theirs or elsewhere, where directed take was occurring. ...
The freshwater tucuxi (Sotalia flluviatilis) and the Amazon River dolphin (Inia geoffrensis) are endemic to the Amazon-Orinoco river basin. Their conservation is hindered by human disturbance and uncertainty about total population size and distribution. In this study, we used rapid assessment questionnaires to identify threats to river dolphins Peru and to identify priority areas for their further study and conservation. We administered questionnaires to fishers (surveyed 2010 n = 162, 2015 n = 251) and community members (surveyed 2015 only; n = 118) at 12 landing ports of the Peruvian Amazon, asking questions about their knowledge, perception and interactions with river dolphins. Dolphins were observed by interviewed fishers based across all ports except for Aguaytia port, which was subsequently excluded from further analysis. Across the sampled ports in 2010, an average of 86% of fishers (range: 59-100%; n = 8 ports) associated dolphins with negative economic impacts, largely due to net damage with similar findings in the more extensive survey in 2015 (74%, 27-100%; n = 11 ports). Bycatch of dolphins was also reported in 11 ports, with a higher incidence in the Loreto, where up to 10 bycaught individuals per fisher per year were reported for both time periods. The use of dolphins as bait has been practised from at least 2010 (2010: 31% of fishers, 11-57%; 2015: 31%, 0-63%) and is prevalent (>40%) in four of the surveyed ports (Caballococha, Bagazan, Requena and Manantay). Our study can be used as a first reference to guide monitoring of river dolphin populations in priority areas. Future efforts should revisit and extend this survey to other ports in Peru. Doing so will enable detection of trends in fisheries conflicts with river dolphins and improve the estimation of bycatch and direct take of dolphins in the Peruvian Amazon.
... de la escorrentía de la deforestación y el 3% de las emisiones atmosféricas de la quema . La presencia de mercurio en ambientes acuáticos constituye uno de los principales problemas que afectan globalmente los ecosistemas marinos y continentales, como las cuencas del Amazonas y el Orinoco, con registros de este contaminante en peces, nutrias y recientemente en delfines de río y costeros (Rosas & Lethi, 1996 ;Dias Fonseca et al., 2005;Siciliano et al., 2008;Panebianco et al., 2011;Salinas et al., 2013;Nuñez-Avellaneda et al., 2014;Mosquera-Guerra et al., 2015, a, b;Venturieri et al., 2017). Actualmente, los altos niveles de concentraciones de mercurio son un problema de salud pública, ya que los pueblos indígenas y los pescadores de los ríos Tapajos y Teles Pires en la Amazonía brasileña, tienen altos niveles de este contaminante, con valores que excedieron el límite propuesto Capítulo IV 120 para humanos por la OMS (0.5 -1 ), basado en análisis de cabello (Dorea et al., 2005). ...
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River dolphins (Inia and Sotalia) have evolved in the different aquatic ecosystems associated with the Amazon, Grande, Iténez - Mamoré, Araguaia - Tocantis and Orinoco rivers. Aspects related to their distribution, movement ecology, habitat use and threats to conservation for these cetaceans in South America were studied. The distribution models generated for the South American river dolphins, integrated 35,594 presence georeferenced records and 19 environmental variables were integrated in niche models of potential distribution for species in the genera: Inia and Sotalia, using the MaxEnt algorithm. We evaluated the degree of overlap between dolphin´s distribution and dam area of influence (i) under construction, ii) operating, and iii) planned dam projects. We found a differential representation of river dolphin´s distribution within protected areas in the region (overlap, ranging between 4.630 Km2 and 18.386 Km2). On the other hand, we verified a differential degree of overlapping between areas of influence of dam projects and river dolphin´s distribution, with the recently described I. araguaiaensis (54.9 % of its distribution within dam´s influence area) as the most affected species. Already constructed dam areas of influence, accounted for the greatest overlap with river dolpohin´s distribution (2.704 Km2 and 41.843 Km2). Operating dams are currently affecting 19.7% of dolphin´s distribution (145.278 Km2/736.458 Km2). As soon as under constructions projects start operating, we expect an addition of 91.302 Km2 in the area of affectation. Finally, if planned dams are constructed and operating, the affected area will add 177.744 Km2 more. Under this projected scenario, we expect that 56.2% (414.324 Km2/736.458 Km2) of the area of distribution of South American river dolphins would be affected. In 2017 and 2018, we deployed satellite transmitters to 24 specimens of the genus Inia from the Amazon and Orinoco (Colombia), Juruena and Tapajós (Brazil), San Martín (Bolivia), and Marañon (Peru) River basins. On average, tags emitted signals for 103 days, reporting home ranges of 56.5 km2 with 95% of utilization distribution (UD), and maximum movements between locations of 55.7 km. Our results included a high variation among tagged dolphin individuals in terms of the analyzed spatial metrics. However, we did not find statistical differences in the mean values of the analyzed variables among basins. In the same way, we report no statistically significant differences in terms of spatial variables analyzed between sexes. Satellite technology may allow us to better understand the heterogeneity of the use of aquatic habitats at different spatial and temporal scales, highlighting the importance of the hydroscape connectivity and free flowing rivers to maintain healthy due to the extensive requirements of documented habitats. Further, this study reports the presence of mercury in river dolphins genera Inia and Sotalia. Mercury concentrations were analysed in muscle tissue samples, collected from 46 individuals at the Arauca and Orinoco Rivers (Colombia), the Amazon River (Colombia), a tributary of the Itenez River (Bolivia), and from the Tapajos River (Brazil). Ranges of total mercury (Hg) concentration in muscle tissue of the four different taxa sampled was: I. geoffrensis humboldtiana 0.003 – 3.99 (n=21, Me=0.4), I. g. geoffrensis 0.1 – 2.6 (n=15, Me=0.55), I. boliviensis 0.03 – 0.4 (n=8, Me=0.1), and S. fluviatilis 0.1 – 0.87 (n=2, Me=0.5). The highest Hg concentration in our study, was obtained at the Orinoco basin, recorded from a juvenile male of I. g. humboldtiana (3.99 At the Amazon basin, higher concentrations of mercury were recorded, in the Tapajos River (Brazil) from an adult male of I. g. geoffrensis (2.6 and the Amazon River from an adult female of S. fluviatilis (0.87 Finally, our results highlight a potential transformation of the ideal conditions that allow for the establishment of the species, explaining its distribution with predicted values between 46.6 % and 70.1 % for the evaluated timeframe due to the effects of climate change on aquatic ecosystems of the colombian Orinoquia . The Meta River, has the highest value for the index of freshwater ecosystems degradation followed by the Orinoco basin, water quality and species exploitation appear to be the major stressors for dolphins in these areas. Finally, river confluences were identified as conservation hot spots for dolphin populations. In conclusion, my dissertation demonstrates the high intensity of the effects generated by anthropic origin pressures on river dolphin populations in South America, leading to the transformation of large areas of their current distribution as well as potential population-level effects. Climate change will increase the intensity of its negative effects in the coming years, sharpening its effects on the health of aquatic ecosystems and the broad requirements that these cetaceans present, evidenced through satellite monitoring implemented between 2017-2018. Keywords: Climate Change; Distribution; Aquatic Mammals; Total mercury; Satellite telemetry.
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El mercurio (Hg) es un metal pesado tóxico que provoca daños en el sistema nervioso central, altera el comportamiento humano y provoca impacto en la biota acuática. El objetivo del presente trabajo fue evaluar la bioacumulación por Hg en peces y el riesgo por ingesta en una Comunidad Nativa (CN) en la amazonia peruana durante la estación seca y lluviosa. La CN Santa Rosa de Tamaya y Tipishca se encuentra en la cuenca baja del río Abujao. El estudio se realizó con 119 habitantes agrupados en 22 familias, con edades promedio de 9 y 38 años para niños y adultos, respectivamente. Los peces fueron colectados empleando principalmente redes de arrastre y fueron identificados siguiendo el procedimiento morfológico taxonómico estándar. El contenido de Hg en músculo de los peces se hizo mediante espectrometría de fluorescencia atómica. Los resultados muestran que las cuatro especies de mayor consumo por la CN fueron Pterygoplichthys pardalis (Castelnau, 1855) «Carachama» (Loricariidae), Prochilodus nigricans Spix y Agassiz, 1829 «Boquichico» (Prochilodontidae), Pseudoplatystoma punctifer (Castelnau, 1855) «Doncella» (Pimelodidae) y Calophysus macropterus (Lichtenstein, 1819) «Mota» (Pimelodidae). El nivel de exposición fue extremadamente alto y la peligrosidad fue media. La dosis máxima de consumo permisible por semana de metilmercurio (MeHg) según la OMS es de 1.6 μg MeHg/kg/semana. Este límite fue superado por C. macropterus para niños de la CN. Se concluye que el riesgo a la salud del poblador de la CN de la Amazonía peruana por el MeHg es alto.
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The action plan representas a consensus of a river dolphin group of specialist around South America. It concerns about the status of the currently recognized river dolphin species threats to their survival, and measures needed to better understand and address those threats.
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We report three cases of conflicts with fishing activities of freshwater dolphins Inia geoffrensis and Sotalia fluviatilis in the Western Brazilian Amazon. The animals presented several cuts produced by perforating and cutting objects, especially on the dorsum, sides and flukes. The wounds were probably caused by harpoons and machetes, gear commonly used by local inhabitants for fishing and agricultural practices in the Amazon. The carcasses had not been subsequently used in any way, which suggests that the animals were not killed for consumption. Conflicts with fishermen and persistent cultural taboos may have led to the deaths. These records are an indication of a growing situation of conflict with fishing activities that should be taken into consideration in the conservation policy planning of aquatic mammals in the Amazon.
Mercury and methylmercury levels in fish muscle and scats of the giant otter (Pteronura brasiliensis) of Manu National Park, Peru, and in one gold-mining area in the vicinity of its borders were analyzed. In 68% of fish muscles, total mercury levels exceeded the proposed maximum tolerable level of 0.1 mg kg -1 fresh weight in fish for the European otter (Lutra lutra), and 17.6% exceeded 0.5 mg kg -1 fresh weight, the most common standard for human consumption. The ratio of methylmercury to total mercury in fish muscle was from 61.3% up to 96.9%. No methylmercury and only traces of inorganic mercury could be detected in the otter scats. No data for tissue concentrations of the giant otter are available at the moment, but as a high percentage of fish levels exceeded the tolerable level, as given for the European otter, a possible risk of mercury intoxication in the giant otter can be postulated, on the basis of mercury intoxication in free-living otters in Europe and North America described in the past.
— We studied sequence variation in 16S rDNA in 204 individuals from 37 populations of the land snail Candidula unifasciata (Poiret 1801) across the core species range in France, Switzerland, and Germany. Phylogeographic, nested clade, and coalescence analyses were used to elucidate the species evolutionary history. The study revealed the presence of two major evolutionary lineages that evolved in separate refuges in southeast France as result of previous fragmentation during the Pleistocene. Applying a recent extension of the nested clade analysis (Templeton 2001), we inferred that range expansions along river valleys in independent corridors to the north led eventually to a secondary contact zone of the major clades around the Geneva Basin. There is evidence supporting the idea that the formation of the secondary contact zone and the colonization of Germany might be postglacial events. The phylogeographic history inferred for C. unifasciata differs from general biogeographic patterns of postglacial colonization previously identified for other taxa, and it might represent a common model for species with restricted dispersal.
Dolphin interactions with fishermen have increased significantly and pose potential risks to the boto, Inia geoffrensis (Blainville, 1817), and the tucuxi, Sotalia fluviatilis (Gervais & Deville, 1853). The main objective of the present paper was to describe the existing conflicts between river dolphins and fishermen in the municipality of Manacapuru region. Sixteen fishermen were interviewed in Manacapuru, state of Amazonas, Brazil who described a situation of ongoing conflict that may be unsustainable. Two merchants from Manacapuru made unconfirmed reports on a boto carcass trade. Data collection for this study occurred between April 20th and April 25th, 2009, but the first author had been conducting research on river dolphins and fisheries in Manacapuru and nearby cities since the beginning of 2008, in order to gain the trust of the fishermen interviewed. The hunting and deliberate killing of the species is probably more threatening to botos than their incidental capture in fishing gears in the Manacapuru region. This practice may result from the fact that dolphins are prone to damaging fishing equipment, and stealing (and possibly damaging) fish from the nets. They are portrayed negatively in numerous myths and superstitions of traditional Amazonian folklore, making them extremely undesired or even hated, seen as pests, and used in the piracatinga, Calophysus macropterus (Lichtenstein, 1819) fishery as bait. For tucuxis, incidental capture still represents the major threat to their conservation in the region evaluated here.
The Amazon River dolphin (Inia geoffrensis), or boto, is illegally harvested for use as bait in fisheries for the catfish Calophysus macropterus. To determine the effect of this harvest, we estimated apparent survival for a boto population in the central Brazilian Amazon where direct harvest is known to have occurred since 2000. For our analysis, we used capture and recapture/resighting data of 528 marked botos over a 17-year period (1994–2011). Time-dependent models estimated that apparent survival after the first reports of harvest (ϕ = 0.899; SE = 0.007) was significantly lower than in years prior to harvest (ϕ = 0.968; SE = 0.009). The decline in apparent survival suggests that current harvest rates exceed conservation limits and may be unsustainable. This issue requires the attention of natural resource managers from all countries of the Amazon basin, as the harvest is widespread and decline in survival could be mirrored in numerous locales.
The fat, protein, copper, iron, zinc, aluminium, magnesium, manganese, calcium, sodium, potassium, vitamin A and mercury contents were determined in the milk of a lactating Amazon river dolpin (Inia geoffrensis), caught in the Amazon River near Manaus, Brazil. The fat content determined in this study (6.9%) was lower than that reported previously for Inia in Venezuela, and for some captive marine dolphins. The protein concentration (9.6%) was higher than that reported for the Venezuelan Amazon river dolpin, but similar to that of the marine dolphins. Concerning the minerals, only calcium, manganese, sodium and potassium could be compared. The Mg and Ca concentrations were lower, but K was much higher than the values determined for other dolphins, whereas Na was within the reported ranges. The mercury concentration found in the dolphin's milk (176 ng/ml) was very close to the minimum level of methylmercury toxicity for non-pregnant human adults.