Marine Mammals and Predators in Costa Rica

This project has been amended to incorporate several health and safety measures to allow responsible fielding of teams during the COVID-19 pandemic. Please refer to the COVID Disclosure Form for more details. 

BEFORE FIELDING 

• Vaccination against COVID-19 is required for all participants. Staying up to date with your vaccinations, including receiving booster doses if available, is strongly encouraged. 
• Become familiar with and abide by the local COVID requirements up to date vaccinations, including boosters, mandatory quarantine, or other guidelines. 
• Do not travel to your Earthwatch expedition or program if you: 
  • are experiencing symptoms consistent with COVID-19 (cough, shortness of breath or difficulty breathing, fever, chills, muscle pain, sore throat, or new loss of taste or smell), 
  • are confirmed or suspected as having COVID-19 within the past 10 days
  • have been in close contact with someone suspected or confirmed as having COVID-19 in the past 10 days 
• You are highly encouraged to take a COVID-19 test one day before or the morning of your rendezvous, before meeting up with your team.

WHILE IN THE FIELD 

• Face masks will be required in line with local regulations and/or when instructed by project leadership. In areas or on projects where mask use is no longer required, the use of face masks will be optional. Any individual who wishes to continue to mask will be supported in that decision. 
• Participants and project staff will continue to wash or sanitize hands frequently and maintain physical distance whenever possible. 
• All team members will be asked to monitor their own health through daily health checks. 
• Recreational activities may be limited or require additional face mask requirements to reduce the risk of exposure to team members or to the local community.
• Meals and activities will take place outside whenever possible. 
• Ventilation will be increased indoors and within enclosed vehicles whenever possible

Golfo Dulce, a fiord-like embayment on the southern Pacific coast of Costa Rica, provides an ideal habitat for marine top predators such as cetaceans (whales and dolphins) (Oviedo 2007, Oviedo & Solis 2008, Oviedo et al. 2015, 2018 Pacheco-Polanco et al. 2015). The gulf has long benefited from the large protected terrestrial areas of the Osa Peninsula and adjacent mainland. However, tourism, development, and other human activities are encroaching on this critical habitat and the many species that depend on it. 

There is mounting evidence that Marine Protected Areas (MPAs) increase the health and abundance of key marine species and are therefore considered to be one of the best ways to safeguard the health of coastal ecosystems. But to designate Golfo Dulce as an MPA, scientists first need to understand and demonstrate the importance of this critical ecosystem. 

For more than 15 years, scientists have gathered data on species such as migratory humpback whales, and resident bottlenose and pantropical spotted dolphins, in this marine habitat to evaluate their abundance and distribution. Their findings have led to the establishment of some restrictive measures limiting shipping activities in the gulf area, but more research is clearly needed to guide future development and management strategies. There is a need for an increased focus on the ecological understanding and the preservation of inshore cetaceans in general since they are exposed to the majority of anthropogenic impacts by sharing the coastal habitat interface. 

The preservation of the beauty and well-being of Golfo Dulce’s marine ecosystem benefits everyone—it can help local agencies manage tourism in the area in a sustainable way, which will generate income for the local community and give tourists the opportunity to learn about one of Costa Rica’s great treasures without destroying it. The research conducted by Earthwatch teams will help scientists to assess the importance of this marine habitat and design management plans to protect it.

Unlike in the open ocean, the confined nature of Golfo Dulce makes it possible for us to observe whales and dolphins at the surface for extended periods of time. Through our research, we seek to assess these species’ population sizes and structures, their distribution and habitat preferences, and their socio-behavioral patterns and the ways in which they utilize this habitat. This information will help us develop conservation plans to protect the marine biodiversity in the gulf in the future. Additionally, Golfo Dulce being a low oxygen basin (anoxic), where marine predators thrive, will help us to understand the complex dynamic of possible scenarios of climatic changes driving the expansion of low oxygen zones in the Pacific Ocean and how upper trophic level organisms would respond under this future potential environmental disruption. In other words, Golfo Dulce is a small-scale model of what will come for tropical marine ecosystems. 

Objective 1: Increase the biological information on coastal cetaceans’ critical habitat in Golfo Dulce using behavior sampling and photo-identification. Specifically, this objective seeks to:

• Document changes in habitat-use of known areas of critical importance for dolphins such as foraging areas, breeding and calving habitats, and other areas.
• Document changes in habitat-use within key areas for calving and breeding humpback whales

Objective 2: Deepen the knowledge of the food web that exists in Golfo Dulce to better understand the ecological role of species within a trophic web. 

Our research team will lead you in all research tasks, including observing cetaceans, making photo identifications, recording vocalizations, and collecting data. When you first arrive at camp, you’ll receive an orientation and intensive training on research methods, and during the days that follow, you’ll work in small teams or pairs on the following tasks:

• Observing Cetacean Behavior. We will travel on board a 27-foot (nine-meter) motorboat a few days per team to make observations of whales and dolphins. You’ll record the position of cetaceans and any boats we spot (to help us assess how vessel traffic affects cetacean behavior) with a handheld GPS unit. You’ll also record the size, composition, and behavior of the dolphin and whale groups we see. And at the beginning and end of each survey period, as well as every half-hour throughout it, you’ll record environmental data like water surface temperature and sea condition. In excellent sea condition, you will also help in recording cetaceans’ vocal behavior using a hydrophone. Wildlife sightings are extremely likely, but not guaranteed. While the chance of seeing dolphins is extremely high, whales are a bit less predictable with respect to the timing of their arrivals. We will focus on studying the whales from the southern Pacific. Generally, they arrive in early August and depart in mid-October to their foraging grounds. Migration patterns vary and sightings during these months cannot be guaranteed.
• Documenting the Trophic Web in Golfo Dulce. You’ll help record and describe the species in multi-predator assemblages. We will observe aggregations of schooling fish and predators such as dolphins, seabirds, and sharks. We will collect data on species composition of the aggregations, the length of the event, and the location. 
• Sorting Photos and Identifying Individual Cetaceans. You’ll then help us sort photos by species and attempt to match individuals we’ve sighted with photos of individuals in our photo ID catalog. We use photo ID management software for the matching process, which displays the encounter history of each individual we’ve already identified, along with a high-quality photo of the dorsal fin, which clearly shows natural marks such as notches and nicks. These marks help distinguish between individuals.
• Working with the Local Community: You may help present to and develop and run educational activities for local schools and other community stakeholders, giving you the opportunity to get to know some of the people who live around Golfo Dulce.

Note: All teams will work with dolphins, but only some teams will work with whales. Whales from the southern Pacific generally arrive in early August and depart in mid-October. These are general patterns and vary from season to season. The team has observed much more variation each year, and whale sightings are not guaranteed.

DAILY ACTIVITIES

Weather and research needs can lead to changes in the daily schedule. We appreciate your cooperation and understanding. 

After breakfast, the team will begin their work for the day. Each day’s tasks will rotate between dolphin and whale surveys, trophic web work and sorting and cataloging photos for individual identification. For whale and dolphin surveys, the team will usually establish a priority species of the day and focus on finding that species first. The team will change focus to other species throughout the day as time and conditions allow. Photographs for photo-ID and behavior-acoustic sampling are conducted with each of the focus species.

Lunch is eaten on the boat or in the field. You may help us carry light equipment to the boat and load it on. Photo-identification sessions will take approximately two hours, though groups will be on the boat for up to five hours. Everyone on the boat will have a specific task, such as handling video and photo equipment, recording instrument readings, such as GPS coordinates or keeping track of dolphins’ babies, specifically those of identified resident females. Always ask if you need to switch tasks or rest. 

Once we are back to the camp, we check equipment and store audios, footage and photos collected during the surveys. There will be free time to rest and get out of the sun in the afternoon, followed by data entry and photo ID matching in the evening. The team will eat dinner together, where a discussion on the day’s results and events and the impact on the current research-conservation project is encouraged.

You’re most likely to encounter the target whale and dolphin populations during the following times:

• Spotted Dolphins: year-round
• Bottlenose Dolphins: year-round
• Humpback Whales (Southeast Pacific Population): early August through mid-October; peak presence in August and September

ITINERARY

• Day 1: Arrival; tour of our home base; settling in; orientation and training
• Day 2: Training on dolphin and whale behavior sampling and dolphin photo-identification (including both fieldwork and lab work at camp) and/or possible dolphin survey
• Days 3–7: Boat survey and photo-ID lab work at camp
• Day 8: Time off to explore or photo-ID lab work at camp
• Day 9: Departure

* Please note that not every expedition has couples’ or singles accommodations available. Please call or email Earthwatch to check for availability prior to reserving your space(s) on the team.

SLEEPING

• 2022 Adult Teams: Volunteers will stay at locally run cabins called El Chontal, situated in the small community of Rincon. Participants will be assigned single bedrooms within the accommodations. The hostel provides sheets, pillows, blankets, and a bath towel (however, bringing an extra one will be wise). 
• 2023 Teen/Student Teams & Select Adult Teams (Feb–Mar 2023): Volunteers will stay at locally-run cabins called El Chontal, situated in the small community of Rincon. Cabins will be shared between two or more volunteers of the same gender. The hostel provides sheets, pillows, blankets, and a bath towel (however, bringing an extra one will be wise).
• 2023 Adult Teams (July–Dec 2023): Volunteers will stay at a small hotel in the port town of Golfito called Vista Castillo Hotel. Rooms will be shared between two or more volunteers of the same gender. Due to the layout of rooms, some volunteers may sleep in bunk beds.  

* Earthwatch will honor each person’s assertion of gender identity, respectfully and without judgment. For both teen and adult teams, where logistics dictate single-sex accommodations or other facilities, participant placements will be made in accordance with the gender identity the participant specified on their Earthwatch Participant form and/or preferences indicated in discussions with Earthwatch.

BATHROOMS

For all teams, bathrooms are shared between 2–3 same-gender volunteers. Hot water showers and flush toilets are available.

There is no bathroom on the boat. The boat is small and does not have an inside cabin. There will be a bucket available for bathroom use in the event someone cannot wait for land. This is standard for small boats and routine for the crew. Everyone aboard will make sure to turn away and provide as much privacy as possible.

ELECTRICITY

Electricity is 120 volts, 60 hertz, Type A and Type B plugs (as in the U.S.). You may charge electronic equipment, but please avoid plugging in many appliances at once.

PERSONAL COMMUNICATIONS

There is cell reception at both the El Chontal cabins and in Golfito. Please check with your service provider regarding coverage in Costa Rica. Golfito has payphones available, but they do not accept prepaid calling cards from foreign countries. If you’d like to make calls during your stay, you should pick up an international prepaid card when you arrive in Costa Rica. The U.S. standard voltage used for small appliances, hair dryers, electronic equipment, etc. is 120 volts, 60Hz, supplied through type A or B sockets.

Please note: Earthwatch encourages volunteers to minimize outgoing calls and immerse themselves in the experience; likewise, family and friends should restrict calls to urgent messages only. Emergency communications will be prioritized.

DISTANCE TO THE FIELD SITE

Teams based in Rincon will depart from the Puerto Jimenez pier for conducting research activities on the boat and travel to different areas in Golfo Dulce. The drive from Rincon to Puerto Jimenez is approximately 30 minutes.  

Teams based in Golfito will depart directly from the dock at the hotel to access various research sites. 

FOOD AND WATER

You’ll enjoy typical Costa Rican fare on this expedition, including rice and black beans, meat, vegetables, fruit, coffee, and juice. The team will eat breakfast and dinner together at the accommodations and will pack lunches to take into the field each day. The local staff will do all meal prep.

TYPICAL MEALS

The following are examples of foods you may find in the field. Variety depends on availability. We appreciate your flexibility.

• Breakfast: Gallo pinto (rice and beans, the best in the country), plantains, fresh cheese, eggs
• Lunch: Sandwiches, fruit (e.g., watermelon, pineapple, bananas)
• Dinner: Costa Rican-style rice and chicken, salad, pasta with homemade sauce
• Snacks: Each breakfast and dinner will be accompanied by amazing fresh, local fruit juice. The local grocery store is always well stocked with ice cream at our request; the local brand Dos Pinos is very good. You will have the opportunity to buy snacks during the day.
• Beverages: We keep a container of filtered water exclusively for the use of participants. We refill the bottle regularly. We encourage constant hydration and water consumption. You’ll sweat a lot even when not exerting yourself, so it’s a good idea to replenish essential electrolytes by drinking a sports drink (e.g., Gatorade) at least once a day.

SPECIAL DIETARY REQUIREMENTS

Please alert Earthwatch to any special dietary requirements (e.g., diabetes, lactose intolerance, nut, or other food allergies, vegetarian or vegan diets) as soon as possible, and note them in the space provided on your volunteer forms.

This expedition can accommodate most special diets with advance notice. We can provide full options for vegetarians and even vegans, some other dietary requirements such as gluten-free food might be a challenge in Golfo Dulce and Osa Peninsula in general. However, if volunteers, due to very specific diets, bring food complements we gladly assist with special meals preparation.

The information that follows is as accurate as possible, but please keep in mind that conditions may change.

The camp is on flat terrain, but any hikes (optional) will likely be in hilly areas. The site is about 10 meters above sea level.

The general climate throughout the year is humid and tropical, with a rainy season that extends from May to early November. The dry season runs from mid-November to April, but even during this period, it’s still very humid with regular afternoon showers.

GENERAL CONDITIONS

For weather and region-specific information, please visit Wunderground.com and search for your project location.

All participants must be able to: 

• Enjoy being outdoors most of the day in variable weather, in the potential presence of wild animals and insects.
• Tolerate 30°C (85°F) heat and high humidity levels.
• Spend long hours sitting on a boat (some may experience seasickness) for an average of 5 hours per day with only access to a bucket on the boat to relieve yourself for 3–4 days per team.
• Search for dolphin signs (jumps, unusual ripples in the water, movements) on the surface of the water, while moving aboard the survey boat and on a screen while sitting at a ground station.
• Carry personal daily supplies such as lunch, water, and some small field equipment.
• Climb into and down out of a minibus and ride, seated with the seatbelt fastened, for up to 1.5 hours a day (team dependent).
• Follow verbal and/or visual instructions independently or with the assistance of a companion.
• Take an active role in your own safety by recognizing and avoiding hazards if and when they arise (including, but not limited to, those described in Earthwatch materials and safety briefings). Always comply with project staff instructions and recommended safety measures.
• Be able to effectively communicate to the staff if you are experiencing distress or need assistance.
• Be able to get along with a variety of people from different backgrounds and ages, often in close proximity, for the duration of your team.
• Be comfortable being surrounded by a language and/or culture that is different from your own.

EMERGENCIES IN THE FIELD

We have a VHF radio on the boat, mobile phones and two-way radios in some areas, and a landline phone at the cabins. Project staff members are not medical professionals.

Earthwatch has a 24-hour, 7-day-a-week emergency hotline number. Someone is always on call to respond to messages that come into our live answering service.

IMMUNIZATIONS & TRAVEL VACCINATIONS

Please be sure your routine immunizations are up to date (for example: diphtheria, pertussis, tetanus, polio, measles, mumps, rubella, and varicella) and you have the appropriate vaccinations for your travel destination. Medical decisions are the responsibility of each volunteer and his or her doctor. Visit the Center for Disease Control and Prevention or the World Health Organization for guidance on immunizations. 

If traveling from countries or regions where yellow fever is endemic, you must have a certificate of vaccination.

Vaccination against COVID-19 is required for all participants. Staying up to date with your vaccinations, including receiving booster doses as applicable is strongly encouraged. 

TRANSPORTATION

We may encounter poor road conditions and landslides. Only qualified drivers will transport volunteers in project vehicles; we ensure project vehicles are well maintained. Seat belts must be worn at all times. Volunteers are not permitted to drive.

HIKING

Hiking may be offered as an optional recreational activity. You’ll likely traverse uneven terrain and hike uphill in humid tropical conditions; there is a risk of sprains, strains, or breaks due to falling or tripping. You should never walk ahead of the local guide and should follow the guide’s instructions. Wear comfortable, closed-toed shoes when walking. At night, carry a personal headlamp or flashlight.

ANIMALS

Poisonous snakes live in the area, but we have never had a snakebite incident. You’ll likely encounter many insects; wear long-sleeved shirts and long pants and apply insect repellent frequently to avoid bites. Those with insect allergies should bring the proper emergency treatment and inform staff of the problem and the location of the treatment.

CLIMATE/WEATHER

Dehydration, heat exhaustion, sunburn, and other heat-related illnesses can occur, but you can protect yourself by drinking sufficient water, wearing high-SPF sunscreen, and wearing appropriate clothing. Dehydration from sweating can be a problem; please bring your own water bottles that you can easily carry and refill them with electrolyte packets. Because of the high humidity, people who use a hearing aid device may find it doesn’t work properly. Consider purchasing a hearing aid dehumidifier.

PROJECT TASKS/EQUIPMENT

Tripping over ropes on the boat or injury from equipment is possible. You will receive a full safety briefing on arrival; please follow all staff instructions. A first aid kit will be available on the boat.

WORKING ON A BOAT

There is a risk of sprains, strains, or breaks from stepping in and out of the boat, or during adverse sea conditions. We will use a ladder when entering and exiting the boat. Hazards may result from falling overboard. Some volunteers may get seasick; please bring seasickness medication as a precaution. Boarding and stepping out of an inflatable craft and/or sitting onboard when the sea is choppy may cause problems for those with mobility or spinal conditions. These volunteers should carefully consider participation on the project. In addition, volunteers with back, knee, and hip problems, or pregnant women, may face difficulties or discomfort not only when they step on board and leave the boat, but also during navigation under choppy sea conditions. Life jackets will be available to each participant and must be worn whenever leaving the inner basin of the gulf and as directed by project staff. Appropriate footwear must be always worn while on deck and the vessel is underway.

PERSONAL SECURITY

Avoid areas designated as off limits by project staff.

SWIMMING

Swimming may be possible during recreational time if volunteers are competent swimmers and project staff has vetted the location. You may only swim in known, safe environments, close to the boat while it is at anchor, and under the supervision of project staff. Do not swim alone.

DISTANCE FROM MEDICAL CARE

It may take an hour or more to arrange transport and reach the hospital. If you have a chronic condition which could require immediate medical care (e.g., heart conditions, kidney problems, severe asthma, etc.), or if you are pregnant, please discuss your participation on this expedition with your physician.

DISEASE

Diseases found in Costa Rica may include malaria, dengue fever, Zika, tuberculosis, filariasis, leishmaniasis, onchocerciasis, trypanosomiasis, schistosomiasis, strongyloidiasis, hepatitis, leptospirosis, chikungunya, and typhoid. Please see the U.S. Centers for Disease Control and Prevention (cdc.gov) or the World Health Organization (who.int) websites for more information on these conditions and how to avoid them. You can decrease your risk of most diseases above by avoiding mosquito bites, practicing good hygiene, and drinking only bottled or filtered water when appropriate. If you feel ill once you return from your trip, make sure you inform your doctor that you have recently returned from a tropical region. A note on vaccinations and treatment: Malaria is not present at the project area.

COVID-19 DISEASE RISKS

COVID-19 is an infectious coronavirus disease, which has caused a world-wide pandemic since its discovery in late 2019. Although most people who have COVID-19 will experience mild to moderate respiratory illness, COVID-19 can also cause severe illness and even death. Some groups, including older adults and people who have certain underlying medical conditions, are at an increased risk of severe illness. The COVID-19 virus spreads from person to person via close contact, primarily through exposure to the respiratory droplets of an infected person.  

Projects and participants fielding with Earthwatch commit to a number of enhanced safety measures described in the COVID Disclosure Form, including wearing face masks when required by local guidelines or requested by team leadership, regular hand washing, and daily health checks. 

Proof of vaccination is required to join this project.

DISEASE

Other diseases found in Costa Rica may include malaria, dengue fever, Zika, tuberculosis, filariasis, leishmaniasis, onchocerciasis, trypanosomiasis, schistosomiasis, strongyloidiasis, hepatitis, leptospirosis, chikungunya, and typhoid. Please see the U.S. Centers for Disease Control and Prevention (cdc.gov) or the World Health Organization (who.int) websites for more information on these conditions and how to avoid them. You can decrease your risk of most diseases above by avoiding mosquito bites, practicing good hygiene, and drinking only bottled or filtered water when appropriate. If you feel ill once you return from your trip, make sure you inform your doctor that you have recently returned from a tropical region. A note on vaccinations and treatment: Malaria is not present at the project area.

RENDEZVOUS LOCATION

Puerto Jimenez Airport, Puerto Jiménez, Costa Rica OR Golfito, Golfito, Costa Rica*

*Please Note: The rendezvous location is team dependent. Teams based at El Chontal in Rincon will rendezvous at the Puerto Jimenez Airport, and those staying at Vista Castillo in Golfito will rendezvous at Golfito Airport. Registered participants may view rendezvous and departure details in their Expedition Logistics Document. This document will populate in your MyEarthwatch Portal once it becomes available. 

* Additional information will be provided by Earthwatch to meet your team. Please do not book travel arrangements such as flights until you have received additional information from Earthwatch.

ABOUT YOUR DESTINATION

Earthwatch strongly recommends that travelers investigate their destination prior to departure. Familiarity with the destination’s entry/exit requirements, visas, local laws, and customs can go a long way to ensuring smooth travel. The U.S. Department of State's Traveler’s Checklist and Destination Guides are helpful resources. For LGBTI travelers, the U.S. Department of State's LGBTI Travelers page contains many useful tips and links.

COUNTRY AND PROJECT ENTRY REQUIREMENTS

You are responsible for reviewing and abiding by the local COVID guidelines and regulations for your destination. This may include proof of testing upon arrival or departure, up to date vaccinations against COVID-19, including boosters, mandatory quarantine, or other requirements.

For information regarding Costa Rica, please visit: https://cr.usembassy.gov/covid-19-information/.  

Entry visa requirements differ by country of origin, layover, and destination, and do change unexpectedly. For this reason, please confirm your visa requirements at the time of booking and, again, 90 days prior to travel. Please apply early for your visa (we recommend starting 6 months prior to the start of your expedition). Refunds will not be made for volunteers canceling due to not obtaining their visa in time to meet the team at the rendezvous. You can find up to date visa requirements at the following website: www.travisa.com.

If a visa is required, participants should apply for a TOURIST visa. Please note that obtaining a visa can take weeks or even months. We strongly recommend using a visa agency, which can both expedite and simplify the process. 

Generally, passports must be valid for at least six months from the date of entry and a return ticket is required.

ARTICLES

• Oviedo Lenin. 2007. Dolphin sympatric ecology in a tropical fjord: habitat partitioning by bathymetry and topography as a strategy to coexist. Journal of the Marine Biological Association. U.K. 87: 1327–1335.
• Oviedo, Lenin et al. 2008. “The song of the southeast pacific humpback whale (Megaptera novaeangliae) off Las Perlas Archipelago, Panama: preliminary characterization.” Aquatic Mammals. 34: 458-463
• Oviedo, Lenin and Mauricio Solis. 2008. “Underwater topography determines critical breeding habitat for humpback whales near Osa Peninsula, Costa Rica: implications for Marine Protected Areas.” Revista de Biología Tropical. 56(2): 591-602
• Bessesen, B., Oviedo, L., Burdett Hart, L., Herra-Miranda, D., Pacheco-Polanco J.D., Baker, L., Saborío-R, G., Bermúdez-Villapol, L. & A. Acevedo-Gutiérrez. 2014. Lacaziosis-like disease among bottlenose dolphins Tursiops truncatus photographed in Golfo Dulce, Costa Rica. Diseases of Aquatic Organisms. 107(3): 173-180.
• David Herra-Miranda, Oviedo, L., Pacheco-Polanco, J.D. and M. Iñiguez. 2015. Spatial analysis of coastal cetaceans’ critical habitats in Golfo Dulce, Costa Rica: considerations for a marina construction project. IWC/66a/SC/E9. Paper presented at the 66th International Whaling Commision Meeting in San Diego, California 2015.
• Oviedo, L. Fernandez, Marc., Herra-Miranda, David., Pacheco-Polanco, J.D., Hernandez Camacho, C and D. Aurioles. 2018. Habitat partitioning mediates the coexistence of sympatric dolphins in a tropical fjord-like embayment. Journal of Mammalogy.
• Pelayo-González L., Oviedo L., Márquez-Artavia A., Herra-Miranda D., Pacheco-Polanco J. D., Bessesen B., Guzmán H. M. (2022) Habitat use of south-eastern Pacific humpback whales (Megaptera novaeangliae; Borowski 1781) in Golfo Dulce, Costa Rica. Marine and Freshwater Research. https://doi.org/10.1071/MF21357

BOOKS

• Kricher, John. A Neotropical Companion. 2nd ed. Princeton, N.J.: Princeton University Press, 1999. (The best book on the beauty of the tropical rainforest.)
• Hoyt, Erich. Seasons of the Whale. Moray, Scotland: Colin Baxter, 1998. (The best book on the life of the humpback whale.)

FIELD GUIDES

• Shirihai, Hadoram and Brett Jarrett. 2006. Whales, Dolphins, and Other Marine Mammals of the World. Princeton, N.J.: Princeton University Press.
• Folkens, Pieter A. 2002. Guide to Marine Mammals of the World. New York: Knopf.
• Garrigues, Richard and Robert Dean. 2007. The Birds of Costa Rica: A Field Guide. Ithaca, N.Y.: Cornell University Press.

PROJECT-RELATED WEBSITE

• instagram.com/dolphinsgd
• cetaceansgolfodulce.blogspot.com
• facebook.com/CEICdolphins
• http://www.golfodulce.org/biodiversity.html

LITERATURE CITED

• Oviedo, L. (2007). Dolphin sympatric ecology in a tropical fjord: habitat partitioning by bathymetry and topography as a strategy to coexist. Journal of Marine Biological Association of the United Kingdom 87, 1-9.
• Oviedo L. and M. Solis. (2008) Underwater topography determines critical breeding habitat for humpback whales near Osa Peninsula, Costa Rica: implications for Marine Protected Areas. Revista de Biología Tropical 56, 591-602.
• Oviedo, L. Herra-Miranda, D., Pacheco-Polanco, D., Figgener, C. Marquez-Artavia, A., Quirós Pereira, W. and M. Iñiguez. (2015). Diversidad de cetáceos en el paisaje marino-costeros de Golfo Dulce, Península de Osa, Costa Rica. Revista de Biología Tropical, 63 (2), 395-406.
• Oviedo, L. Fernandez, Marc., Herra-Miranda, David., Pacheco-Polanco, J.D., Hernandez Camacho, C and D. Aurioles. 2018. Habitat partitioning mediates the coexistence of sympatric dolphins in a tropical fjord-like embayment. Journal of Mammalogy