| Keyword |
Description |
| Disturbance |
Change that breaks the calm |
| Intertidal |
The coastal zone that is exposed at low tide and covered at high tide |
| Estuary |
A coastal area where freshwater mixes with seawater, often sheltered and rich in food |
Pacific harbor seals, the whiskered “sea puppies” of the West Coast, are disappearing fast from their southernmost home in Baja California. New research led by the public institute CICESE, with UABC and UDLAP, reports a 61.2% drop on the peninsula in just six years: from 7,380 seals in 2016 to 2,863 in 2022. Aerial surveys taken between April and June show that the number of breeding and resting sites has collapsed from 44 colonies in 2009 to only four in 2025. The species is not listed as endangered, but it does have special protection under Mexico’s NOM-059 standard, which is under review. Scientists now urge authorities to reconsider the seal’s conservation status.
Harbor seals rely on nearshore waters, especially the subtidal and intertidal zones, where they can forage and then haul out to rest, molt, and nurse pups. They favor bays and estuary mouths and often gather on rocky shores, mudflats, and sandbars. A single colony can include dozens to hundreds of animals using the same site year after year. Unlike the much larger elephant seal, harbor seals are smaller, quieter, and highly sensitive to disturbance. If people, vehicles, or noisy machinery approach too closely, seals repeatedly flush into the water, wasting energy and sometimes abandoning places that mothers need for pupping.
Researchers point to two pressures that combine into a dangerous spiral. First, if food availability is low, females cannot build the fat reserves needed to carry a pregnancy to term or to produce enough milk, so fewer pups survive. Second, persistent disturbance — including nearby rock quarrying and increased human presence — pushes seals off haul-out sites during critical periods. Both forces mirror a wider signal: coastal ecosystems are under stress, and when top predators struggle, it is often because the web of prey, habitat, and quiet space is fraying.
Protecting harbor seals means protecting the coast itself. Practical steps include creating quiet zones around pupping and molting areas, restricting heavy equipment and vehicle access during breeding months, improving monitoring of colonies by air and land, and safeguarding prey and water quality in bays and estuaries. Education for boaters, anglers, and tourists can reduce close approaches and noise. Given the sharp decline on the Baja Peninsula, updating protections under NOM-059 — and funding enforcement — would help stabilize remaining colonies while scientists continue to track trends and identify the most at-risk sites.
Bridging words
These words sound similar in English and Spanish: Why not practice them now?
| English |
Spanish |
| Special protection |
Protección especial |
| Conservation status |
Estado de conservación |
| Tourists |
Turistas |
Time to discuss
- Why are harbor seals important to coastal ecosystems?
- What human activities should be limited near seal colonies?
- Should Mexico upgrade the harbor seal’s protection status?
Let's write
Answer the following questions in one paragraph:
- Design a simple conservation plan for one Baja haul-out site, explaining actions, timing, and who should be involved.
- Explain how food availability affects seal reproduction, using examples from the study.
