1. California sea lions: Los Islotes or La Lobera is
a breeding colony north of the Espiritu Santo
Archipelago Marine Area National Park, which
on average hosts around 900 California sea lions
(Zalophus californianus) during the summer
(breeding season). It is the only breeding colony
in the Bay of La Paz and surrounding areas, and
is renowned for its good health and growth
compared to other breeding colonies within the
Gulf of California. It is also an area of great
economic importance for tourism, since the
observation of sea lions performing their
reproductive activities (nursing, giving birth,
copulation, fights between territorial males) and
swimming with this species, is one of the main
tourist attractions in the Bay of La Paz. This
charismatic species is one of the main natural
values of the National Park, not only for its
economic importance but also for its relevant
role in the coastal ecosystems of the Gulf of
California and the Baja California peninsula,
because it acts as a regulator of fish populations
(its prey) in the surroundings of its colonies and
has ideal characteristics for monitoring the
quality of coastal environments.
2. Seabirds: Birds are one of the main objects of
protection that prompted the decree for the
creation of the National Park, as they are
nesting, resting and/or feeding areas for 78
species of marine and aquatic birds, of which 13
are under some category of risk according to
NOM-059-SEMARNAT-2010. Species such as the
yellow-legged kittiwake (Larus livens), the heron
(Ardea herodias santilucae), the brown pelican
(Pelecanus occidentalis), the oystercatcher
(Haematopus palliatus), the osprey (Pandion
haliaetus), frigatebird (Fregata magnificens),
least petrel (Oceanodroma microsoma), black
petrel (Oceanodroma melania) and reddish
egret (Egretta rufescens) use the islands and
islets of the Espiritu Santo Archipelago as
nesting grounds.
3. Habitat rocky reefs: In the Park, benthic
coastal marine habitats between 0 and 25 m
depth represent a total area of 71.4 km2. The
rocky reef habitat occupies more than one fifth
of the total coastal area, with an area of 16 km2
corresponding to 22.38 % of the total. In some
cases the habitat is dominated by sea fans and
sponges, but commonly it is dominated by
macroalgae of the filamentous type, which are
grouped in the functional category of "Turf". In
terms of fish richness, diversity and biomass, the
rocky reefs are more important than the other
coastal benthic habitats in the Park, supporting
on average 85 species of fish and 78 species of
invertebrates, of which 31 species (3 invertebrates and 16 fish) are of commercial
importance.
1. Sealions: Counts conducted
during the breeding season (August)
2016 at Los Islotes recorded a total
of 525 fur seals of which 29 were
adult males, 36 sub-adults, 220
females, 35 juveniles, 162 pups and
43 miscellaneous. The age structure
at Los Islotes was characterised by
mainly females and pups, due to the
fact that it is a breeding colony.
During the breeding season (July) of
2023 at Los Islotes a total of 874 sea
lions were recorded, of which 27
were males, 28 sub-adults, 453
females, 79 juveniles, 261 pups and
25 miscellaneous. The number of
births recorded in 2023 is the
highest reported in the last 10 years,
when births fluctuated between 160
and 200 pups.
2. Seabirds: In contrast to the 6,125
individuals recorded in 2015, in
2022 the abundance of seabirds and
waterbirds recorded was 54,963
individuals. This is due to the
management measures to protect
the breeding sites of the different
birds, such as not landing on nesting
islets, restrictions on approaching
bird colonies and partial closures of
beaches.
3. Rocky reef habitat: In terms of
fish richness, diversity and biomass,
the rocky reefs are more important
than the other benthic coastal
habitats, hosting on average 85 fish
species and 78 invertebrate species,
of which 31 species (3 invertebrate
and 16 fish species) are of
commercial importance. In 2019 The
mean value of the number of fish
species was 14.60 ± 0.41 spp/census
(mean ± standard error). The
average number of organisms at the
sites sampled within the Park was
191.47 ± 13.55 individuals/census.
1. Sealions: Counts conducted during
the breeding season (August) 2016 at
Los Islotes recorded a total of 525 fur
seals of which 29 were adult males, 36
sub-adults, 220 females, 35 juveniles,
162 pups and 43 miscellaneous. The age
structure at Los Islotes was
characterised by mainly females and
pups, due to the fact that it is a breeding
colony. During the breeding season
(July) of 2023 at Los Islotes a total of 874
sea lions were recorded, of which 27
were males, 28 sub-adults, 453 females,
79 juveniles, 261 pups and 25
miscellaneous. The number of births
recorded in 2023 is the highest reported
in the last 10 years, when births
fluctuated between 160 and 200 pups.
2. Seabirds: In 2015 the abundance of
seabirds and waterbirds recorded was
6,125 individuals per year, while species
richness was 32. The average richness
per month was 15.5 species, with
November (20 species) and December
(25 species) being the richest months. In
2022, 64 species of marine and aquatic
birds were recorded, of which 28 are
exclusively marine, 15 shorebirds, 11
shorebirds and 10 terrestrial/coastal
birds. The dominant species in the
community are the frigatebird (Fregata
magnificens), the brown pelican
(Pelecanus occidentalis) and the yellowlegged gull (Larus livens).
3. Habitat rocky reefs: Descriptive
ecological indices of abundance (N),
richness (S), Shannon-Wiener diversity
(H') and Shannon-Wiener diversity (H')
were estimated in 2015 as response
variables and indicators of reef
condition. The mean value of fish
species richness was 20.02 ± 0.67
spp/census (mean ± standard error). The
mean value of fish abundance was
453.35 ± 71.32 individuals/census. The
mean diversity value was 0.85 ± 0.02
decits/census. The mean invertebrate
species richness value was 8.00 ± 0.29
spp/census. The mean invertebrate abundance value was 48.54 ± 3.11
individual/census. The mean diversity
value was 0.68 ± 0.01 decits/census.
1. Sea lions: The "Los Islotes" colony has
increased at an annual rate of 3.8%
reaching approximately 900 individuals in
2023. Despite two significant declines in
2015 and 2019, associated with the
unusual warming period since 2014 and
El Niño 2015, the population recovered
and continued to increase. The number
of births has increased at a rate of 4. In
2023, the number of hatchlings increased
markedly, their body condition was good
and remained within the range reported
for this colony for the last two decades.
2. Seabirds: The richness and abundance
values of the first years of monitoring,
2015 to 2017, with respect to the period
2018 to 2022 have a positive trend
increasing from an average per month of
15.5 species to 23.5 and from 6,125
individuals in 2015 to 54,963 in 2022.
This is due to an increase in monitoring
effort, in addition to the management
measures put in place. A total of 64
species of waterfowl and seabirds were
recorded, with the dominant species
being the yellow-legged gull, brown
pelican and frigate bird.
3. Rocky reef habitat: In the comparison
of the traditional ecological indices of
richness, abundance, diversity and equity
from 2005 to 2019 for both fish and
invertebrates, three decreases in index
values can be observed, one in 2009, one
in 2013 and the third in 2019, but
regardless of the overall fluctuations, a
negative trend can be observed. The
average fish richness decreased from
19.5 sp/transect to 14.6 sp/transect.
Abundance also declined from 570.1
individuals/transect to 191.4
individuals/transect, equity from a value
of 0.8 to 0.6 and diversity from 0.8 to 0.6 decits/census. In invertebrates, as with
fish, there was a large decrease in mean
richness, from 13.7 sp/transect to 5.7
sp/transect. Abundance dropped from
187.0 individuals/transect to 29.1
individuals/transect. In equity from a
value of 0.8 to 0.7 (Figure 35) and in
diversity from 0.8 to 0.5 decits/census.
1. Shelter: The marine habitats allow the
preservation of emblematic species with some
degree of special protection, such as the
California sea lion, frigate, yellow-legged gull
and sea turtles; in addition, the corals provide
coastal protection, habitat for fish and
invertebrates, and breeding grounds for
commercial fish.
2. Production of food: The Park is a feeding and
refuge site for aquatic species, with artisanal
fishing being one of the most important
economic activities, as it helps sustain dozens
of families in the city of La Paz by providing
sustainable fish production.
3. Recreational activities: The ecosystem of the
National Park allows the development of
recreational, educational, observation, and
research activities, such as swimming with sea
lions, observation of bird colonies, observation
of underwater flora and fauna.
1. High visitation in the Park makes
it more urgent to have mechanisms
in place to reduce impacts on the
ecosystem, so the buoy system
helps to limit the number of visitors
per site and thus reduce the
negative impacts of human
activities.
2. The strategy of closing the lobera
during the months of June to August
contributes to maintaining a colony
with less stress, has a more
successful breeding season, avoids
accidents to visitors, and is
considered the healthiest colony in
the Gulf of California. With respect
to reef health, in 2018 the
Integrated Reef Health Index was
"Good", compared to 2014 where
the index was "Poor".
3. The daily yield associated with
fishery production reflects 94.92 kg
representing $105 USD per unit
effort. The fish catch from 2009 to
2013 remained from 1 - 13 ton, with
an increase from 2014 with a peak
in 2016 of 164 ton in the overall
catch and 109 ton catch in the
species of interest.
1. Buoys and swim system: in 2018,
the installation of the buoy system
in the Park was completed, and in
2022 the anchoring system of the
buoys was replaced for greater
efficiency and to improve the
appearance of the seabed, so that
there are currently 44 buoys, of
which 34 are for mooring and 10 for
signalling, for the sites with the
greatest influx of visitors. In 2022,
40,353 visitors were registered in
the Park, which represented an
income of $255,000 USD in fees,
compared to 2018, when an income
of $215,000 USD was registered.
2. In 2017, a total of 535 individuals
of sea lions were recorded at the
Los Islotes colony, by July 2023 a
maximum of 874 were recorded,
making it the fastest growing
breeding colony in the Gulf of
California. With respect to coral
reefs, in 2018, 38.7% coral cover
was reported at the 11 sites within
the park with the highest coral
cover.
3. Between 2009 and 2022, a catch
of fishery species of commercial
interest and general catch of 893.73
tonnes was recorded, where 66.39%
corresponds only to species of
commercial interest with a total of
593.38 tonnes.
1. The colony of sea lions at Los Islotes is the
only one with a sustained growth rate of 3.84%
per year in the entire Gulf of California, which
leads to the export of sea lions to the other
colonies, which will help the repopulation of
this species in the Gulf of California. It
represents a good indicator of the Park's health
to maintain this growth of the colony and
allows the development of tourist activities,
which are carried out in an orderly manner due
to the existing rules.
2. Information gathered by scientific studies
and research improves the knowledge of
species and ecosystems, which contributes to
the implementation of efficient measures for
their conservation. The Park's Public Use
Programme allows an orderly use of all the
important natural values of the park, such as
the observation of the bird colonies, the rocky
and coral reefs, the mobulas and hammerhead
sharks, and the sea lion colony, where there
are clear rules on how to observe each species
or group of species. The accreditation of guides
and captains has been fundamental, so that they are aware of all the Park's regulations and
the care they must take when carrying out
their activities.
3. The trend of the natural values of the Park is
towards the recovery of the species, this is
demonstrated by the increase in the size and
biomass of fish, as shown by the results of the
annual monitoring carried out in the Park, as
well as the return of hammerhead sharks 5
years ago, with schools of more than 200
animals, after an absence of more than 20
years in the area. The protection of the birthing
grounds has helped to maintain the mobula
populations in excellent health with groups of
more than 5000 animals all over the outer side
of the island. In addition, the blue carbon
quantification calculation conducted in 2021
(UABCS/Niparajá) estimated carbon
sequestration in the mangrove and coral
ecosystems to be a total of 2,282.339 tonnes of
carbon per year.
