Pacific nurse shark in Los Cabos

How to recognize it

A large shark with a broad, flattened, rounded head, small eyes, a small mouth set under the snout and a pair of fleshy barbels hanging in front of it. The two dorsal fins are rounded, similar in size and set far back, and the long tail, about a third of the total length, has almost no lower lobe. Adults are yellowish brown to grayish brown with a paler belly; young ones have small dark spots, smaller than the eye, and faint saddles on the back.

Biology

The Pacific nurse shark is found only in the eastern Pacific, from the southern tip of Baja California and the Gulf of California to Peru, including Cocos and Malpelo islands. It lives over rocky reefs, sand flats and near mangroves, from the surface to about 30 m, and spends almost all its time on the bottom. Until 2015 it was lumped with the Atlantic nurse shark; it differs in body proportions, with the dorsal fins closer together and set further forward, and in its teeth, which have more side points.

It eats bottom animals: fish, crabs and shrimp, octopus and squid, snails, clams and sea urchins. Its biology is still poorly known. In Santa Elena Bay, Costa Rica, 28 tagged sharks of 0.85 to 2.6 m returned to the bay year after year and used its warmer water as a refuge when seasonal upwelling chilled the surrounding sea, sometimes gathering in tight groups.

How it's caught in Los Cabos

The Pacific nurse shark is a snorkel and dive shark, not a fishing target, and it is seldom reported around Los Cabos. Look for it resting on sand or under rocky ledges in shallow water, especially at Cabo Pulmo. Watch without touching: it looks sluggish, but a nurse shark that is grabbed or cornered can bite and hold on.

If one is hooked by accident, we release it. Best practice: circle hooks that aren’t stainless steel, keep the shark in the water, unhook it quickly or cut the leader close to the hook, and hold it facing forward while the boat moves slowly so water runs over its gills. Never lift a big shark by the tail or gills.

Rules, records & conservation

Top Anglers practices catch-and-release for all sharks.

Don't confuse it with

The Pacific lemon shark is also yellowish brown with two similar-sized dorsal fins, but it has no barbels, a pointed snout and a large lower tail lobe, and it swims rather than lying on the bottom. Horn sharks, which some Mexican fishers also call gata, are much smaller and have a spine at the front of each dorsal fin.

Questions

By Max VargasTop Anglers, Cabo San Lucas · international judge at big game fishing world championships · reviewed October 2026

Sources

• Del Moral-Flores et al. 2015, description of Ginglymostoma unami (Rev. Mex. Biodiversidad)
• Eschmeyer’s Catalog of Fishes: Ginglymostoma unami
• FishBase: Ginglymostoma unami
• Smithsonian STRI: eastern Pacific fishes, Ginglymostoma unami
• Ayres et al. 2021, drone shark surveys in Cabo Pulmo (J. Fish Biol.)
• Madrigal-Mora et al. 2024, Pacific nurse shark site fidelity (Mar. Ecol. Prog. Ser.)
• Save Our Seas Foundation: Pacific nurse shark project
• Florida Museum: nurse shark
• ISRA factsheet: Cabo Pulmo Important Shark and Ray Area
• Florida Museum, International Shark Attack File: species implicated
• NOM-029-PESC-2006 (PROFEPA)
• NOM-017-PESC-1994, 2013 amendment (DOF)
• Shark closed season agreement, 2012 (DOF)

Top illustration: Top Anglers. Photos: iNaturalist contributors, credited on each photo.