Fewer Whales, Warmer Ocean: A 2026 Alert for Golfo Dulce

Local whale-watching guides are reporting unusually few humpback whale sightings in Golfo Dulce this season. At the same time, the Eastern Tropical Pacific is experiencing exceptional ocean warming. The connection is not yet proven, but it deserves close attention.

August is normally one of the most reliable months for encountering humpback whales in Golfo Dulce.

In 2026, something appears different.

Experienced local guides have reported that humpbacks have been considerably harder to find. On one recent morning, according to local reports, only one of approximately 30 to 40 boats searching the area encountered a whale.

Some guides have also observed that whales appear to be spending less time inside Golfo Dulce than in previous seasons.

These observations are important. But they need to be interpreted carefully.

Fewer sightings do not necessarily mean fewer whales

There is currently no scientific population estimate demonstrating that fewer humpback whales have migrated to Costa Rica in 2026.

The whales may instead be changing where they spend their time, how long they remain inside Golfo Dulce or when they move between different parts of Costa Rica's southern Pacific coast.

One possible factor deserves particular attention: ocean temperature.

NOAA's August 2026 Marine Heatwave Outlook reports marine heatwave conditions in the Eastern Pacific. For the Eastern Tropical Pacific, NOAA estimates a 90–100% probability of marine heatwave conditions continuing through the remainder of 2026.

At the same time, El Niño conditions are strengthening across the tropical Pacific.

That does not prove that warm water is driving humpback whales away from Golfo Dulce.

But recent scientific research has already shown that humpback whale occurrence and migration timing in Costa Rican waters can be associated with changing environmental conditions.

The combination makes the unusual observations of 2026 scientifically interesting.

Why Golfo Dulce matters

Golfo Dulce is an important breeding and nursery habitat for humpback whales migrating from the Southern Hemisphere.

Whales from the endangered Central American population also use Costa Rica's Pacific waters during another part of the year.

This makes the region an exceptional natural laboratory for understanding how a changing Pacific Ocean may affect humpback migration.

But observations become scientifically valuable only when they are recorded consistently.

Knowing that somebody saw three whales on one day and none the next tells us relatively little unless we also know how long they searched, how far they travelled and under what environmental conditions.

2026 could become an important reference year

At #SaveGolfoDulce, we believe the unusual 2026 season reinforces the need for systematic long-term monitoring.

Future observations should record not only the number of whales encountered, but also:

• survey duration and distance

• GPS location

• group composition and presence of calves

• sea and weather conditions

• water temperature

• whale behaviour

• vessel activity

Over several seasons, consistent data could help distinguish normal annual variation from longer-term changes in whale distribution and migration.

For now, the correct conclusion is not that Golfo Dulce is “losing its whales.”

The correct conclusion is that something unusual may be happening, and we should be measuring it.

Protecting Golfo Dulce begins with understanding how this extraordinary ecosystem is changing.

Sources

Local observations reported by The Tico Times and El Observador CR, 24 August 2026.

NOAA Physical Sciences Laboratory, Marine Heatwave Forecast Monthly Report, August 2026.