Long-Distance summer marine expeditions from Loreto: Witnessing Fin whale courtship beyond the Park Boundaries
Fin whale photographed August 2025 in Loreto outside National Park boundaries by Regina Domingo, Baja Adventures.
The fin whale population in the Gulf of California is truly unique, genetically isolated, non-migratory, and residing year-round in this beautiful semi-enclosed sea. While research has long sought to understand their reproductive patterns, new science combined with recent field observations is providing exciting insights into their seasonal behaviors.
Fin whale photographed August 2025 in Loreto outside National Park boundaries by Regina Domingo, Baja Adventures.
This week, we had a surprising encounter north of Coronados Island, just outside the northern boundary of the park. While following a group of dolphins, two fin whales suddenly appeared and began exhibiting courtship behaviors. It was an incredible, unexpected moment.
We were able to take some photo identifications to share with our researchers, then gave the whales space to continue undisturbed. We hope this signals positive breeding success and that more calves will be born into this unique population in the Gulf of California.
A groundbreaking study, research article : Sex steroid hormones and behavior reveal seasonal reproduction in a resident fin whale population used non-invasive hormone analysis from blubber biopsies to revealed a clear seasonal reproductive cycle for these fin whales. Testosterone in males peaks during late summer, around August, coinciding with observed courtship behaviors, while females show patterns consistent with pregnancy or ovulation during this time. This confirms that mating and reproduction primarily occur in late summer and autumn, even though this is the least biologically productive season in the Gulf.
Fin whales are generally found aggregating in key areas such as Ballenas Channel, Kino Bay, Santa Rosalia, Loreto Bay, and La Paz Bay, which provide essential habitat for feeding and breeding.
These encounter further supported the scientific findings of a summer breeding season and highlighted the importance of protecting critical habitat areas beyond established park boundaries.
The discovery of seasonal reproductive behavior contrasts with other resident whale populations that breed year-round, suggesting adaptive responses to environmental factors such as shifting prey availability.
Fin whale photographed August 2025 in Loreto outside National Park boundaries by Regina Domingo, Baja Adventures.
These findings underscore the need for informed conservation strategies that account for the seasonal cycle and extended habitat use by fin whales in the Gulf of California. By combining innovative hormone research with field observations like ours, we can help ensure the protection and sustainability of this small but remarkable whale population amidst ongoing environmental change.
Baja Adventures is honored to witness such majestic moments and stands committed to supporting conservation efforts that safeguard the future of fin whales and their fragile Gulf of California ecosystem.
Regina Domingo, Baja Adventures, during conversations with our guests