Long-distance spring expeditions in Loreto: Unveiling the Gulf of California’s resident Fin whales
Fin whale photographed in Loreto by Regina Domingo, Baja Adventures expedition wildlife guide.
Aboard the Puma, our long distance expeditions venture into the most remote islands of Loreto Bay National Park, Montserrat and Santa Catalina. The Gulf of California’s nutrient-rich waters—dubbed “The Aquarium of the World” by Jacques Cousteau—host an extraordinary spectacle: resident fin whales (Balaenoptera physalus) cruising alongside their calves, cruising through the Sea of Cortez’s cobalt depths.
The Gulf of California is home to a genetically and acoustically distinct population of resident fin whales (Balaenoptera physalus), which are classified as Vulnerable on the IUCN Red List due to their low genetic diversity and small population size. Estimates suggest there are between 250 and 820 individuals, with key nursery areas located in Bahía de La Paz, the San José Channel, and Ángel de la Guarda Island. These whales feed in highly productive areas such as Loreto, Bahía de los Ángeles, Canal de Ballenas, and Bahía Kino, where seasonal upwellings provide abundant prey like krill and small fish. Unlike migratory populations, these fin whales remain within the Gulf year-round, adapting their movements to seasonal prey availability.
Fin whale photographed in Loreto by Regina Domingo, Baja Adventures expedition wildlife guide.
During the cool season, fin whales travel northward along the western margin of the Gulf of California, where environmental conditions are dominated by a combined north-south current and outgoing tidal currents acting to aggregate euphausiids (Nyctiphanes simplex), which are the principal prey for fin whales in the Gulf of California, . This season is also the breeding season for the euphausiids, producing more than 80% of the calyptopis larval phase in the mid-southern Gulf of California, at Carmen Island , Montserrat and Santa Catalina islands (off Loreto), San Jose Island, in the Baja California Peninsula .
The Year-Round Guardians of the Gulf; Fin Whales in the Gulf of California: Feeding ecology, movements, and conservation
Feeding Habits
Fin whales in the Gulf of California exhibit specialized foraging strategies tied to the region’s seasonal productivity. As filter-feeding baleen whales, they primarily consume euphausiids (krill, notably Nyctiphanes simplex) and small schooling fish like herring and mackerel. Their signature lunge-feeding technique—accelerating with mouths open to engulf up to 70 cubic meters of prey-laden water—allows them to exploit dense prey patches at depths of 100–300 meters during daylight. At night, they shift to shallower dives (<15 m), tracking the vertical migration of krill.
Fin whale photographed in Loreto by Regina Domingo, Baja Adventures expedition wildlife guide.
Seasonal movements in the Gulf year-round, adapting to its dynamic ecosystem.
The movements of these resident fin whales are driven by wind-driven upwellings that boost marine productivity:
Winter–Spring: Concentrate near Loreto and the southern Gulf, where cold-season upwellings create krill-rich zones.
Summer–Autumn: Migrate north to the Mechudo Corridor and Bahía de los Ángeles, following seasonal phytoplankton blooms and prey shifts. Satellite tagging reveals some individuals travel to the Midriff Islands, aligning with elevated chlorophyll levels.
Diel Patterns: Daytime deep dives (100–200 m) target euphausiid swarms, while nocturnal shallow dives (<50 m) focus on fish near the surface.
Fin whale photographed in Loreto by Regina Domingo, Baja Adventures expedition wildlife guide.
Unique traits
Size: Second-largest whale species (up to 27 m, 80 tons).
Vocalizations: Produce 188-decibel calls, among the loudest animal sounds.
Ecological Role: As apex predators, they enhance nutrient cycling by concentrating prey and fecal plumes.
Leopoldo Sanmiguel, Baja Adventures founder looking through binoculars during a long distance marine expedition in Loreto.
Citizen science insights
Our marine expeditions in Loreto contribute data on cetacean movements and prey interactions, aiding conservation strategies for this resilient yet vulnerable population, highlighting the Gulf’s role as a critical year-round habitat for fin whales and other cetaceans.
Regina Domingo, Baja Adventures expedition wildlife guide.
