| Keyword |
Description |
| Vanishing |
Disappear suddenly and completely |
| Mudflats |
A stretch of muddy land left uncovered at low tide. |
| Disturbance |
The interruption of a settled and peaceful condition |
Pacific harbor seals, the playful “sea puppies” with long whiskers, are disappearing fast from Baja California, their southernmost home. A new study led by CICESE, with support from UABC and UDLAP, found a 61.2% drop in just six years: from 7,380 seals in 2016 to 2,863 in 2022. Aerial counts show their colony numbers shrinking too, from 44 sites in 2009 to only four by 2025. Even though the species is not officially endangered, it currently has special protection under Mexico’s NOM-059, which is being reviewed. Scientists say this is the right time to reconsider its status, because a vanishing top predator often signals bigger problems for both land and sea.
Harbor seals live in nearshore waters where they can find food and quickly haul out to rest. They like rocky shores, mudflats, and sandbars near bays and an estuary mouth. Many use the intertidal zone, the strip that is covered at high tide and exposed at low tide. These quiet places help mothers give birth and nurse pups. Harbor seals are smaller and shyer than elephant seals, and they get stressed by noise and people. If boats, cars, or heavy machines come close, seals panic and rush into the water again and again. That wastes energy and may cause them to abandon safe resting spots.
Researchers point to two main pressures. First, when food is scarce, females cannot build enough fat to carry a pregnancy to term or produce milk, so fewer pups survive. Second, constant disturbance — including nearby rock quarrying and more human activity — pushes seals off their haul-out areas at the worst times. To help, experts suggest quiet zones around pupping sites, limits on vehicles and loud work during breeding months, better monitoring, and keeping water clean so prey stays healthy. Updating protections under NOM-059 and funding real enforcement could give the remaining colonies a chance to recover.
Bridging words
These words sound similar in English and Spanish: Why not practice them now?
| English |
Spanish |
| Status |
Estatus |
| Human activity |
Actividad humana |
| Experts |
Expertos |
Time to discuss
- Why are the seals disappearing so quickly?
- How can people avoid disturbing seal colonies?
- Should Mexico strengthen protections for harbor seals?
Let's write
Answer the following questions in one paragraph:
- Describe a simple plan to protect one seal colony during the breeding season.
- Explain how little food can reduce the number of seal pups.
