GALAPAGOS BULLHEAD SHARK

Taxonomy:

Phylum– Chordata

Class– Chondrichthyles

Subclass– Elasmobranchii

Infraclass– Euselachii

Superorder– Selachimorpha

Order– Heterodontiformes

Common Name– Bullhead Sharks

Family– Heterodontidae

Common Name– Bullhead Sharks

Genus– Heterodontus

Species– quoyi

Status: IUCN Red List DATA DEFICIENT

Average Size and Length: They are born around 17 cm. Mature males measure around 48 cm. The maximum recorded has been 61 cm and possibly 107 cm.

The egg case is 11 cm long.

Teeth and Jaw: The small front teeth are pointy and sharp for grabbing prey. The side teeth are flat, perfect for cracking and grinding shells.

Head: They have a large head and a stubby snout. The nostrils do extend to the mouth. There are small spiracles behind the eyes.

Demographic, Distribution, Habitat, Environment and Range: The Galapagos Bullhead shark can be found in the east Pacific on the coast and around the islands near Peru and the Galapagos Islands. There might be another Heterodontus species from Peru which is Heterodontus peruanus, but these two cannot be separated as of this time for lack of materials examined. They live in rocky habitats and coral reefs in tropical climates. They rest on ledges of vertical rocks and surfaces between 16-30 m inshore continental and insular waters. Like all sharks, the Galapagos shark depends heavily on its surrounding environment, and is extremely sensitive to any changes such as climate change. The Galapagos shark depends on cold upwellings of sea water around the Galapagos Islands. That means that changes in water temperature would have a direct impact on the life of this uncommon species.

Diet: They mainly feed on crabs and possibly other small invertebrates and fish.

Ram-Suction Index: Like the other members of its family, the Galapagos Bullhead shark is more than likely high on the suction side of the index. They more than likely suck in prey and water from rocks and crevices and use their unique different teeth to pierce the prey with its sharp front teeth when the jaw extends, and crush and grind it with its molar like back teeth.

Aesthetic Identification: The Galapagos Bullhead shark is light grey or brown with large black spots that are larger than half of the eye diameter. Those spots are smaller and less distinct in young sharks. There are mottled dark spots or blotches under the eyes. There is no light bar between the eyes. The origin of the first dorsal fin is over the pectoral fin inner margins. Both dorsal fins have spines. They have very large pectoral fins and an anal fin.

Biology and Reproduction: They are thought to be oviparous like the rest of their family. Not much else is known about the reproduction habits of the Galapagos Bullhead shark.

The shark embryos are protected within tough, auger or spiral-shaped eggs. This shape enables them to be wedged into rock crevices for protection from predators. The females wedge them in when they are soft, and after a few days the egg cases harden and are very difficult to move. When the egg cases are soft, they are lighter in color. When they harden, they become a much darker caramel brown color.

Behavioral Traits, Sensing and Intelligence: The Behavior of the Galapagos Bullhead shark is mostly unknown; however, some research suggests they may have some similar behavioral traits as other members of their family. They are nocturnal. They rest on cracks and crevices during the day, and are actively moving and hunting around their environment at night.

Speed: More than likely, they are poor swimmers, sluggish and slow moving just as the other members of their family are. The more than likely use their large pectoral fins to help it walk across the seabed and rocky surfaces and hold on to the rocks when hanging vertically. They probably have the ability to rest motionless on the bottom, while eating and breathing at the same time, like the other members of its family.

Galapagos Bullhead Shark Future and Conservation: There is not enough data to evaluate them. Despite their current status, one group is striving to gather more data and protect this beautiful and unique species of shark. The Galapagos Bullhead Shark Project are putting efforts in place. As of the end of 2017, the project has made significant progress, with a total of 100 individuals being tissue sampled and photographed throughout the nine identified nursery areas for bullhead sharks in Galapagos, across six islands. A new “hot-spot” for bullhead sharks was also discovered in 2017 on Española.

As a key part of all Galapagos Conservation Trust (GCT) projects is to engage with local stakeholders and community members, the team has actively sought their involvement with the project. Subsequently, the research cruises were carried out in partnership with three local students, three Ecuadorian researchers, seven international volunteers and Marine Park Rangers, who helped plan and implement all data collection.

The team has successfully collaborated with scientists from Peru to try and establish whether the bullheads found off mainland Peru are indeed a separate species. Tissue samples from both populations are currently being analyzed at the Galapagos Science Center in San Cristobal, with their results potentially evidencing another endemic species to the Archipelago.

Click here to read more about the project and the Galapagos Conservation Trust

Galapagos Bullhead Shark Recorded Attacks on Humans: Harmless to humans (unless stressed), the Galapagos Bullhead shark poses no threat. Their spines can impose a painful wound if not careful.