Historia 8 tortugas ingles

PRESENTS

FUTURE FOR BAJA CALIFORNIA’S GREEN SEA TURTLES PROMISING

INSTRUCTIONS:

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THE GREEN SEA TURTLE (Chelonia mydas)

BONE STRUCTURE

GENERAL FACTS

Uper view 1 meter

Class: reptile Diet: mainly herbivorous Average lifespan: 50-100 years Size: up to 1 m Weight: up to 150 Kg East Pacific population segment: • Smaller • Darker pigmentation

CONSERVATION STATUS:

VARIABLE DIET

Throughout its life, this long-lived specie occupies various habitats separated by thousands of kilometers. This life-history, makes research in this species’ biology and population dynamics particularly complex. Overfishing took it to the brink of extinction, but thanks to conservation efforts, populations have increased in recent years.

Adult green sea turtles are the only herbivorous sea turtles. However, as juveniles they are omnivorous.

(SEA TURTLES IN THE MEXICAN PACIFIC)

LIFE CYLE

This species is a survivor: its path to the sea is filled with dangers from incubation until adulthood.

MULTICOLORED CARAPACE

Mexican law: endangered IUCN: endangered

The shell can be up to one meter long, and has black, grey, green, brown, and yellow coloration.

Breeding seasons happen at regular intervals of two, three or even five years.

REPRODUCTIVE PHASE

Low view

IN NUMBERS

1,500

COASTAL AREA

HAWKSBILL Eretmochelys imbricata

LEATHERBACK Dermochelys coriacea Mexican law: endangered IUCN: endangered

LOGGERHEAD Caretta caretta Mexican law: endangered IUCN: endangered

ANATOMY

They prefer lagoons or bays with abundant vegetation.

BIRTH

KILÓMETERS: distance covered during migrations

GREEN TURTLE Chelonia mydas

Between 15 and 50 years can go by between the moment turtles first reach the sea until their return to the beach where they were born.

3-5

YEARS: duration of the migratory cycle

100

Mexican law: endangered IUCN: endangered

JUVENILE PHASE

EGGS that can be laid by a sea turtle in a single nest. They take six to eight weeks to hatch.

Migratory cycles between feeding and nesting areas begin

1 OUT OF

1,000-10,000

Return to the beach where they were born

hatchlings reaches adulthood

OLIVE RIDLEY Lepidochelys olivacea

As juveniles, green sea turtles enter feeding areas, where they can spend decades until they reach reproductive age.

Ley mexicana: threatened IUCN: vulnerable

TO LEARN MORE

THE GREEN SEA TURTLE PHOTOSTORY

RELATED STORIES

DATAMARES

TIMELINE RETURN TO HOME

THE GREEN SEA TURTLE (Chelonia mydas)

BONE STRUCTURE

GENERAL FACTS

Uper view 1 meter

Class: reptile Diet: mainly herbivorous Average lifespan: 50-100 years Size: up to 1 m Weight: up to 150 Kg East Pacific population segment: • Smaller • Darker pigmentation

CONSERVATION STATUS:

VARIABLE DIET

Throughout its life, this long-lived specie occupies various habitats separated by thousands of kilometers. This life-history, makes research in this species’ biology and population dynamics particularly complex. Overfishing took it to the brink of extinction, but thanks to conservation efforts, populations have increased in recent years.

Adult green sea turtles are the only herbivorous sea turtles. However, as juveniles they are omnivorous.

(SEA TURTLES IN THE MEXICAN PACIFIC)

LIFE CYLE

This species is a survivor: its path to the sea is filled with dangers from incubation until adulthood.

MULTICOLORED CARAPACE

HAWKSBILL Eretmochelys imbricata Mexican law: endangered IUCN: endangered

The shell can be up to one meter long, and has black, grey, green, brown, and yellow coloration.

Nesting season Nesting usually occurs in summer.

The temperature of the sand determines the hatchlings’ sex.

LEATHERBACK Dermochelys coriacea Mexican law: endangered IUCN: endangered

LOGGERHEAD Caretta caretta

Low view

IN NUMBERS

1,500

Birth When a hatchling leaves the egg, it stimulates others with its movements so they will do the same, and leave the nest as a group.

ANATOMY

COASTAL AREA

They prefer lagoons or bays with abundant vegetation.

KILÓMETERS: distance covered during migrations

3-5

GREEN TURTLE Chelonia mydas

In each nesting season, a sea turtle can lay one

to eight nests.

YEARS: duration of the migratory cycle

100

EGGS that can be laid by a sea turtle in a single nest. They take six to eight weeks to hatch.

Returning home Females return to the beach where they were born to lay their eggs. The cycle repeats it self as a process, and at the same place.

1 OUT OF

1,000-10,000 hatchlings reaches adulthood

Mexican law: endangered IUCN: endangered

Getting to know the ocean After leaving the nest, hatchlings instinctively go towards the ocean. Generally, they swim towards open water.

Sexual maturity Sea turtles can take 10 to 50 years to reach sexual maturity, depending on the species. When this happens, they migrate to tropical and subtropical waters to mate and nest.

It’s estimated that only one in every thousand turtles reaches adulthood.

Mexican law: endangered IUCN: endangered

OLIVE RIDLEY Lepidochelys olivacea Ley mexicana: threatened IUCN: vulnerable

= 10 TURTLES

TO LEARN MORE

THE GREEN SEA TURTLE PHOTOSTORY

RELATED STORIES

DATAMARES

TIMELINE RETURN TO HOME

THE GREEN SEA TURTLE (Chelonia mydas)

Throughout its life, this long-lived specie occupies various habitats separated by thousands of kilometers. This life-history, makes research in this species’ biology and population dynamics particularly complex. Overfishing took it to the brink of extinction, but thanks to conservation efforts, populations have increased in recent years.

GENERAL FACTS

Uper view 1 meter

Class: reptile Diet: mainly herbivorous Average lifespan: 50-100 years Size: up to 1 m Weight: up to 150 Kg East Pacific population segment: • Smaller • Darker pigmentation

BONE STRUCTURE

A HARD HELMET

CONSERVATION STATUS:

A sea turtle’s skull is very strong, and its beak has a higher density which gives it a strong bite. They can’t pull their head or flippers into their shells.

(SEA TURTLES IN THE MEXICAN PACIFIC)

LIFE CYLE

This species is a survivor: its path to the sea is filled with dangers from incubation until adulthood.

SHELL

The bony parts of the shell conform a shield in a cupular form with thick plates that protect the entire anatomy of the turtle.

Mexican law: endangered IUCN: endangered

Breeding seasons happen at regular intervals of two, three or even five years.

REPRODUCTIVE PHASE

IN NUMBERS

1,500

KILÓMETERS: distance covered during migrations

The phalanges of their fins are elongated to give power when swimming, and provide a powerful boost.

LIKE HANDS

3-5

YEARS: duration of the migratory cycle

Although they are not visible, the fin bones form five fingers, similar to the human extremities.

Migratory cycles between feeding and nesting areas begin

1,000-10,000

Return to the beach where they were born

hatchlings reaches adulthood

LOGGERHEAD Caretta caretta

GREEN TURTLE Chelonia mydas

Between 15 and 50 years can go by between the moment turtles first reach the sea until their return to the beach where they were born.

Mexican law: endangered IUCN: endangered

JUVENILE PHASE

1 OUT OF

Mexican law: endangered IUCN: endangered

BIRTH

100

EGGS that can be laid by a sea turtle in a single nest. They take six to eight weeks to hatch.

LEATHERBACK Dermochelys coriacea

Mexican law: endangered IUCN: endangered

ANATOMY

FINS

HAWKSBILL Eretmochelys imbricata

OLIVE RIDLEY Lepidochelys olivacea

As juveniles, green sea turtles enter feeding areas, where they can spend decades until they reach reproductive age.

Ley mexicana: threatened IUCN: vulnerable

TO LEARN MORE

THE GREEN SEA TURTLE PHOTOSTORY

RELATED STORIES

DATAMARES

TIMELINE RETURN TO HOME

THE GREEN SEA TURTLE (Chelonia mydas)

Throughout its life, this long-lived specie occupies various habitats separated by thousands of kilometers. This life-history, makes research in this species’ biology and population dynamics particularly complex. Overfishing took it to the brink of extinction, but thanks to conservation efforts, populations have increased in recent years.

GENERAL FACTS

Uper view 1 meter

Class: reptile Diet: mainly herbivorous Average lifespan: 50-100 years Size: up to 1 m Weight: up to 150 Kg East Pacific population segment: • Smaller • Darker pigmentation

BONE STRUCTURE

ARMORED

CONSERVATION STATUS:

Its heart is protected by its humeri and carapace structure. Its lungs are in the upper section.

(SEA TURTLES IN THE MEXICAN PACIFIC)

LIFE CYLE

This species is a survivor: its path to the sea is filled with dangers from incubation until adulthood.

ELASTIC MUSCLES

The musculature of his back allows him to move with ease and elasticity with a powerful flutter.

Mexican law: endangered IUCN: endangered

Breeding seasons happen at regular intervals of two, three or even five years.

REPRODUCTIVE PHASE

Low view

IN NUMBERS

1,500

DIGESTIVE SYSTEM

HAWKSBILL Eretmochelys imbricata

LEATHERBACK Dermochelys coriacea Mexican law: endangered IUCN: endangered

LOGGERHEAD Caretta caretta Mexican law: endangered IUCN: endangered

ANATOMY

Your intestines and stomach are very small due to your diet.

BIRTH

KILÓMETERS: distance covered during migrations

GREEN TURTLE Chelonia mydas

Between 15 and 50 years can go by between the moment turtles first reach the sea until their return to the beach where they were born.

3-5

YEARS: duration of the migratory cycle

100

Mexican law: endangered IUCN: endangered

JUVENILE PHASE

EGGS that can be laid by a sea turtle in a single nest. They take six to eight weeks to hatch.

Migratory cycles between feeding and nesting areas begin

1 OUT OF

1,000-10,000

Return to the beach where they were born

hatchlings reaches adulthood

OLIVE RIDLEY Lepidochelys olivacea

As juveniles, green sea turtles enter feeding areas, where they can spend decades until they reach reproductive age.

Ley mexicana: threatened IUCN: vulnerable

TO LEARN MORE

THE GREEN SEA TURTLE PHOTOSTORY

RELATED STORIES

DATAMARES

TIMELINE RETURN TO HOME

COMPLEX PAST AND PROMISING FUTURE FOR BAJA CALIFORNIA’S GREEN SEA TURTLES

Green sea turtles were a sustainable food source in the Baja California peninsula for millenia, but overfishing in the 20th Century to satiate the demand in cities along the U.S.-Mexico border drastically reduced their populations. Scientific monitoring began in the early 2000’s, and baseline abundance data corresponds to a reduced population. In order to understand population tendencies in the present, we must first understand long-term human impacts on this species.

TIMELINE

MAP OF THE STUDY AREA

At a regional level, the study area covers ~ 14,400 km2 in the central desert, and includes two key C. mydas feeding areas that made important contributions to the 20th Century fishery.

By working closely with expert fishers and analyzing historical documents and archaeological data, we reconstructed human impacts over three centuries at two key green sea turtle feeding areas in Baja California, and found encouraging signs for this population.

BAHÍA DE LOS ÁNGELES

GUERRERO NEGRO/LAGUNA OJO DE LIEBRE

Estimated captures (turtles/year)

Estimated captures (turtles/year)

10000

9000

UNITED ESTATES

8000

7000

6000

B.C.N 5000

GULF OF B.C.

4000

3000

SONORA

a

2000

IMPORTANT EVENTS

1000

b 10

1700

1720

1740

1760

1780

1800

1820

1840

1860

1880

1900

1920

1940

1960

1980

2000

2020

HISTORICAL CATEGORIES

B.C.S PACIFIC OCEAN

PREHISPANIC

MISSIONAL

SECULAR

MODERN FISHERIES

Important events:

Important events:

Important events:

Important events:

Bahía de los Ángeles (a) and Guerrero Negro/Laguna Ojo de Liebre (b) Secondary research sites - Missions

Since at least 12,000 years before the present, hunter-gatherers like the Cochimí inhabited the deserts and coasts of the peninsula. Marine resources, and sea turtles in particular, were a fundamental part of their diet and had symbolic importance.

Mining communities Ensenada: Main commercial site Secondary commercial sites

Sea turtles were a key food source during this turbulent period. Jesuit missionaries, envoys of the Spanish crown, arrived in the 18th Century. Epidemics led to mass mortality of the native population, and Manila galeons sailed the coasts, pursued by British pirates.

The missions were closed after Mexican independence, and the permanent human population remained low. Sea turtles continued to be an important food source for whalers and miners, and some small-scale commercial sea turtle fisheries existed.

The rapid growth of cities along the U.S.-Mexico border created an important demand for sea turtle meat. New technologies such as outboard motors and sea turtle nets, along with improved roads, allowed the demand to be satiated efficiently. The fishery collapsed within decades.

Limits of the study area We thank the communities of Bahía de los Ángeles and Guerrero Negro for their trust and partnership. While carrying out this work (2012-2014), M.M.E.C. received an academic grant from the Mexican National Council for Science and Technology-CONACYT for her studies in the Graduate Program in Ocean Sciences and Limnology at the National Autonomous University of Mexico (PCMyL-UNAM).

We are very grateful to Grupo Tortuguero de las Californias A.C., Reserva de la Biósfera El Vizcaíno, Área Natural Protegida de Flora y Fauna Isla del Golfo, and Exportadora de Sal S.A. for logistical support and for kindly providing monitoring data. Field research was primarily funded by grant 2012-383 from the Walton Family Foundation to Grupo Tortuguero de las Californias. This story is based on a peer-reviewed paper published in Fish and Fisheries (Early-Capistrán et al., 2018. https://doi.org/10.1111/faf.12236).

TO LEARN MORE

THE GREEN SEA TURTLE PHOTOSTORY

RELATED STORIES

DATAMARES

TIMELINE RETURN TO HOME

COMPLEX PAST AND PROMISING FUTURE FOR BAJA CALIFORNIA’S GREEN SEA TURTLES

Green sea turtles were a sustainable food source in the Baja California peninsula for millenia, but overfishing in the 20th Century to satiate the demand in cities along the U.S.-Mexico border drastically reduced their populations. Scientific monitoring began in the early 2000’s, and baseline abundance data corresponds to a reduced population. In order to understand population tendencies in the present, we must first understand long-term human impacts on this species.

TIMELINE

MAP OF THE STUDY AREA

At a regional level, the study area covers ~ 14,400 km2 in the central desert, and includes two key C. mydas feeding areas that made important contributions to the 20th Century fishery.

By working closely with expert fishers and analyzing historical documents and archaeological data, we reconstructed human impacts over three centuries at two key green sea turtle feeding areas in Baja California, and found encouraging signs for this population.

BAHÍA DE LOS ÁNGELES

GUERRERO NEGRO/LAGUNA OJO DE LIEBRE

Estimated captures (turtles/year)

Estimated captures (turtles/year)

10000

9000

UNITED ESTATES

8000

7000

6000

B.C.N 5000

GULF OF B.C.

4000

3000

SONORA

a

2000

IMPORTANT EVENTS

1000

b 10

1700

1720

1740

1760

1780

1800

1820

1840

1860

1880

1900

1920

1940

1960

1980

2000

2020

B.C.S PACIFIC OCEAN

Bahía de los Ángeles (a) and Guerrero Negro/Laguna Ojo de Liebre (b) Secondary research sites - Missions Mining communities Ensenada: Main commercial site Secondary commercial sites

1960

Limits of the study area

Market formation for sea turtle products in border cities (Tijuana, Ensenada, and Mexicali).

1965

Introduction of outboard motors and sea turtle nets to the study region.

1980

Scientific monitoring and beach protection begins at the main nesting areas in Michoacán (Colola and Maruata)

1990

Total ban on all sea turtle captures in Mexico.

2001

Scientific monitoring of sea turtles begins in the study region.

TO LEARN MORE

THE GREEN SEA TURTLE PHOTOSTORY

RELATED STORIES

DATAMARES

TIMELINE RETURN TO HOME

COMPLEX PAST AND PROMISING FUTURE FOR BAJA CALIFORNIA’S GREEN SEA TURTLES

Green sea turtles were a sustainable food source in the Baja California peninsula for millenia, but overfishing in the 20th Century to satiate the demand in cities along the U.S.-Mexico border drastically reduced their populations. Scientific monitoring began in the early 2000’s, and baseline abundance data corresponds to a reduced population. In order to understand population tendencies in the present, we must first understand long-term human impacts on this species.

TIMELINE

MAP OF THE STUDY AREA

At a regional level, the study area covers ~ 14,400 km2 in the central desert, and includes two key C. mydas feeding areas that made important contributions to the 20th Century fishery.

By working closely with expert fishers and analyzing historical documents and archaeological data, we reconstructed human impacts over three centuries at two key green sea turtle feeding areas in Baja California, and found encouraging signs for this population.

BAHÍA DE LOS ÁNGELES

GUERRERO NEGRO/LAGUNA OJO DE LIEBRE

Estimated captures (turtles/year)

Estimated captures (turtles/year)

10000

9000

UNITED ESTATES

8000

7000

6000

B.C.N 5000

GULF OF B.C.

4000

3000

SONORA

a

2000

IMPORTANT EVENTS

1000

b 10

1700

1720

1740

1760

1780

1800

1820

1840

1860

1880

1900

1920

1940

1960

1980

2000

2020

HISTORICAL CATEGORIES

B.C.S

PREHISPANIC

PACIFIC OCEAN

MISSIONAL

SECULAR

MODERN FISHERIES

Bahía de los Ángeles (a) and Guerrero Negro/Laguna Ojo de Liebre (b) Secondary research sites - Missions

ROCK PAINTING

HARPOON

Mining communities

Bone harpoon from the Comodú period (250 A.D.-1750) in Laguna Ojo de Liebre. Sea turtles were a key food source for the first inhabitants of the Baja California peninsula, and were hunted from rafts using stone or bone harpoons such as this one.

(Adapted from Ritter et al. 2001).

Ensenada: Main commercial site Secondary commercial sites

Limits of the study area

REPRESENTATIONS OF SEA TURTLES Graphic representation of a sea turtle in rock painting from the Bahía de los Ángeles region. The site contains materials from approximately 960-790 years before the present.

(Ritter et al. 2011). Photo: Michelle María Early Capistrán.

Graphic representations of sea turtles from the Comondú/Cochimí culture. Sea turtles appear in art and funeral offerings, suggesting symbolic or religious importance.

(Adapted from Seminoff et al. 2001).

TO LEARN MORE

THE GREEN SEA TURTLE PHOTOSTORY

RELATED STORIES

DATAMARES

TIMELINE RETURN TO HOME

COMPLEX PAST AND PROMISING FUTURE FOR BAJA CALIFORNIA’S GREEN SEA TURTLES

Green sea turtles were a sustainable food source in the Baja California peninsula for millenia, but overfishing in the 20th Century to satiate the demand in cities along the U.S.-Mexico border drastically reduced their populations. Scientific monitoring began in the early 2000’s, and baseline abundance data corresponds to a reduced population. In order to understand population tendencies in the present, we must first understand long-term human impacts on this species.

TIMELINE

MAP OF THE STUDY AREA

At a regional level, the study area covers ~ 14,400 km2 in the central desert, and includes two key C. mydas feeding areas that made important contributions to the 20th Century fishery.

By working closely with expert fishers and analyzing historical documents and archaeological data, we reconstructed human impacts over three centuries at two key green sea turtle feeding areas in Baja California, and found encouraging signs for this population.

BAHÍA DE LOS ÁNGELES

GUERRERO NEGRO/LAGUNA OJO DE LIEBRE

Estimated captures (turtles/year)

Estimated captures (turtles/year)

10000

9000

UNITED ESTATES

8000

7000

6000

B.C.N 5000

GULF OF B.C.

4000

3000

SONORA

a

2000

IMPORTANT EVENTS

1000

b 10

1700

1720

1740

1760

1780

1800

1820

1840

1860

1880

1900

1920

1940

1960

1980

2000

2020

HISTORICAL CATEGORIES

B.C.S

PREHISPANIC

PACIFIC OCEAN

MISSIONAL

SECULAR

MODERN FISHERIES

Bahía de los Ángeles (a) and Guerrero Negro/Laguna Ojo de Liebre (b) Secondary research sites - Missions

HISTORICAL MAPS

Mining communities

MISSIONARY TEXTS Map of the Gulf of California (circa 1750) by missionary Fernando Consag, which includes Bahía de los Ángeles and the Cochimí Nation.

Missionaries kept detailed records that allowed us to calculate sea turtle consumption during this time period.

Ensenada: Main commercial site Secondary commercial sites

Limits of the study area

BUCCANEER DIARIES Jesuit missionaries recorded the peninsula’s flora and fauna, including sea turtles, in great detail.

Natural history texts from this period provide and interesting glimpse into the past.

(Venegas 1757).

Sea turtles were an important food source for pirates, as they could be kept alive for weeks or months.

Their diaries and logbooks contain detailed description of where, how, and how many turtles were captured during their voyages.

(Cooke 1712).

TO LEARN MORE

THE GREEN SEA TURTLE PHOTOSTORY

RELATED STORIES

DATAMARES

TIMELINE RETURN TO HOME

COMPLEX PAST AND PROMISING FUTURE FOR BAJA CALIFORNIA’S GREEN SEA TURTLES

Green sea turtles were a sustainable food source in the Baja California peninsula for millenia, but overfishing in the 20th Century to satiate the demand in cities along the U.S.-Mexico border drastically reduced their populations. Scientific monitoring began in the early 2000’s, and baseline abundance data corresponds to a reduced population. In order to understand population tendencies in the present, we must first understand long-term human impacts on this species.

TIMELINE

MAP OF THE STUDY AREA

At a regional level, the study area covers ~ 14,400 km2 in the central desert, and includes two key C. mydas feeding areas that made important contributions to the 20th Century fishery.

By working closely with expert fishers and analyzing historical documents and archaeological data, we reconstructed human impacts over three centuries at two key green sea turtle feeding areas in Baja California, and found encouraging signs for this population.

BAHÍA DE LOS ÁNGELES

GUERRERO NEGRO/LAGUNA OJO DE LIEBRE

Estimated captures (turtles/year)

Estimated captures (turtles/year)

10000

9000

UNITED ESTATES

8000

7000

6000

B.C.N 5000

GULF OF B.C.

4000

3000

SONORA

a

2000

IMPORTANT EVENTS

1000

b 10

1700

1720

1740

1760

1780

1800

1820

1840

1860

1880

1900

1920

1940

1960

1980

2000

2020

HISTORICAL CATEGORIES

B.C.S

PREHISPANIC

PACIFIC OCEAN

MISSIONAL

SECULAR

MODERN FISHERIES

Bahía de los Ángeles (a) and Guerrero Negro/Laguna Ojo de Liebre (b) Secondary research sites - Missions

WHALING LOGBOOKS

Mining communities

NATURAL HISTORY TEXTS Example of a logbook from a whaling vessel (1864). Whalers caught turtles for food or commerce, and registered captures in detail. In Laguno Ojo de Liebre, whalers captured between 2 and 100 sea turtles annually between 1858 and 1873.

Ensenada: Main commercial site Secondary commercial sites

Limits of the study area

GREEN SEA TURTLE FISHING, 1920 Illustration of green sea turtle in an 18th Century natural history text.

Taxonomic categories have varied across time, but historical sources distinguished this species because of the gastronomic value of its meat.

(La Cépède 1803).

Green sea turtles were caught in Laguna Ojo de Liebre. Several attempts to establish commercial fisheries in this period failed due to the lack of market demand.

(Averett 1920).

TO LEARN MORE

THE GREEN SEA TURTLE PHOTOSTORY

RELATED STORIES

DATAMARES

TIMELINE RETURN TO HOME

COMPLEX PAST AND PROMISING FUTURE FOR BAJA CALIFORNIA’S GREEN SEA TURTLES

Green sea turtles were a sustainable food source in the Baja California peninsula for millenia, but overfishing in the 20th Century to satiate the demand in cities along the U.S.-Mexico border drastically reduced their populations. Scientific monitoring began in the early 2000’s, and baseline abundance data corresponds to a reduced population. In order to understand population tendencies in the present, we must first understand long-term human impacts on this species.

TIMELINE

MAP OF THE STUDY AREA

At a regional level, the study area covers ~ 14,400 km2 in the central desert, and includes two key C. mydas feeding areas that made important contributions to the 20th Century fishery.

By working closely with expert fishers and analyzing historical documents and archaeological data, we reconstructed human impacts over three centuries at two key green sea turtle feeding areas in Baja California, and found encouraging signs for this population.

BAHÍA DE LOS ÁNGELES

GUERRERO NEGRO/LAGUNA OJO DE LIEBRE

Estimated captures (turtles/year)

Estimated captures (turtles/year)

10000

9000

UNITED ESTATES

8000

7000

6000

B.C.N 5000

GULF OF B.C.

4000

3000

SONORA

a

2000

IMPORTANT EVENTS

1000

b 10

1700

1720

1740

1760

1780

1800

1820

1840

1860

1880

1900

1920

1940

1960

1980

2000

2020

HISTORICAL CATEGORIES

B.C.S

PREHISPANIC

PACIFIC OCEAN

MISSIONAL

SECULAR

MODERN FISHERIES

Bahía de los Ángeles (a) and Guerrero Negro/Laguna Ojo de Liebre (b) Secondary research sites - Missions

THE HARPOONER’S ART

Mining communities

ALEJANDRO ARCE Juan Romero explains the art of sea turtle fishing with harpoons. For centuries, sea turtles were captures with limited technology that required great ability, and restricted captures.

Video: Gerardo Garibay Melo and Michelle María Early Capistrán

Ensenada: Main commercial site Secondary commercial sites

Limits of the study area

TURTLE PEN Interview with Alejandro Arce, who fished along both coasts of the Baja California peninsula for over 40 years. The knowledge accumulated by experts such as him can help us understand long-term change in the oceans.

Photo: Gerardo Garibay Melo

A pen where sea turtles were stored before being shipped to border cities. Improved fishing technologies and roads increased captures exponentially compared to past centuries.

Photo: Díaz family, Bahía de los Ángeles

TO LEARN MORE

THE GREEN SEA TURTLE PHOTOSTORY

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DATAMARES

TIMELINE RETURN TO HOME

PhotoStory Photo credit:

Michelle María Early Capistrán / Gerardo Garibay Melo

The overexploitation of sea turtles in Baja California was a relatively recent event, and older fishers still observed sea turtle abundance before large-scale human impacts occurred. Fishers’ living memory provides important information about past ecosystems, which allows us to establish conservation goals for the future. Green sea turtle populations have increased after decades of protection, but further research is needed to evaluate their current population status. However, there is reason for optimism.

Fishers with an exceptionally large green sea turtle. Unknown date, probably between 1950 and 1960. Photo: Galván family, Bahía de los Ángeles.

Harpoon used for sea turtle fishing until the 1960s. Its use required great ability: the harpooner stood on the prow, signaling the turtle’s position, and threw the harpoon with just enough force to perforate the shell without breaking it. During new moons in summer, they would follow the bioluminiscent stellae left behind my swimming turtles.

Interview with Pablo Murillo, fisher and net weaver from Bahía de los Ángeles. The techniques and gear used by sea turtle fishers was developed through decades of systematic observation of sea turtles’ behavior and their interactions with the marine environment.

Interview with Alejandro Arce, a fisher from Bahía de los Ángeles. Expert fishers, like him, have knowledge gathered over generations living in connection with the sea, which is indispensable for understanding the past and looking towards the future.

Jesús Romero Castillo, chronicler of Guerrero Negro, at the old port. During his decades of work, he has rescued much of the region’s history.

Victor Cortés baits hooks at dawn.

Collaborative work between fishers and scientists can contribute to healthy oceans for future generations.

Today, some fishers in Bahía de los Ángeles and Guerrero Negro participate in sea turtle monitoring, using the same net design developed by their parents and grandparents. Photo: José Arce Smith.

Alberto Abreu (left) and Antonio Reséndiz take blood samples from a sea turtle, circa 1993. Reséndiz was a pioneer in the investigation of sea turtles in the region, and his dedication has been an inspiration for the generations of turtles that have followed him .

Photo: A. Abreu and R. Briseño

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