Description

Common Names: Shortfin Mako Shark, Mako Shark. 

Latin Name: Isurus oxyrinchus  

Family: Lamnidae   

Identification: Long conical snout. Large blue/black eyes. Lower jaw contains multiple rows of inwardly curving teeth. Pectoral fin length shorter than length of head. Juveniles often have more rounded dorsal and pectoral fins. Well developed caudal keel. Crescent shaped tail. Back coloration bright blue to purple/slate grey. Underside off white. In the Shortfin Mako Shark population of the Azores and Cape Verde Islands the underside of the snout and jaw of large adults are dusky which is similar to the Longfin Mako's coloration but characteristic analysis confirms that they are definitely Isurus oxyrinchus.

Size: Maximum recorded size 4.45m but more commonly 2m. Size at birth 60-70cm 

Habitat: Coastal and oceanic in depths of up to 500m. Prefers clear water over turbid. Often seen swimming just below the surface with first dorsal fin visible. 

Abundance and distribution: Circumtropical and temperate in waters usually warmer than 16 degrees. Highly migratory with migrations recorded up to 2500mi.

Diet and Behaviour: The shortfin mako shark cruises open water in search of prey species. It's main diet consists of bony fishes and squid. Wounds and scars on the ventral surface and caudal peduncle of swordfish and tuna indicate that Shortfin Mako Sharks often attack from below. As well as a large assortment of bony fishes, Makos also consume a variety of sharks and rays (especially in South Africa) and larger specimens may attack dolphins and small cetaceans.

Reproduction: Ovoviviparous. Recorded litter size 2 - 10 but may be higher. Gestation has been estimated at 14 months. 

Similar species: Longfin Mako (Isurus paucus). The longfin mako shark is distinguished from the shortfin mako shark by its significantly longer pectoral fins, even larger eyes and dark coloration on the underside of the snout and jaw extending about half way to the gills. Its teeth are also somewhat broader.

Reaction to divers: Initially makes fast, close passes in the presence of chum then slows down and retreats to a more wary distance but continues to make occasional passes. Otherwise difficult to approach. Rarely attacks without provocation but has bitten divers and swimmers. Also known to attack boats.

 

Common Names: Great Hammerhead 

Latin Name: Sphyrna Mokarran 

Family: Sphyrnidae   

Identification: Large size. Dorsal fin proportionately very high and falcate. Leading edge of hammer almost straight with central indent. Body brown to greyish brown. Ventral surface pale.    

Size: Maximum length 6 metres. 50 - 70 cm at birth.   

Habitat: In shore and off shore reefs and surrounding tropical ocean environments. Intertidal to 80 meters. 

Abundance and distribution: Circumtropical. 

Behaviour:  Cruises over sand and reefs in search of prey. Pins stingrays to the sand with hammer whilst disabling them. Swims with an exaggerated swaying of the hammer in order to see forward. 

Reproduction: Viviparous. The hammerhead are considered the most highly evolved of the shark families.   

Similar species: Scalloped hammerhead distinguished by more pronounced scalloping of hammer and proportionately smaller fins, Smooth Hammerhead distinguished by total lack of indentations in leading edge of hammer, and Smalleye hammerhead distinguished by small size and highly convex anterior margin of hammer.  

Reaction to divers: Shy. Moves away unless in a baited situation. May become very bold and make close passes at divers but not normally aggressive. Care should be taken due to large size and previously reported attacks on bathers.  

 

Common Names: Blue shark  

Latin Name: Prionace glauca 

Family: Carcharhinidae 

Identification: Slender body with extremely long pectoral fins. Snout long. Eyes large. Back has a distinct deep blue sheen. Underside  pale. 

Size: Maximum length 3.8 metres. 35-44cm at birth.   

Habitat: Tropical and temperate open ocean environments. In some areas migrates into shallow water at night.  

Abundance and distribution: Circumglobal. The Blue shark probably has the greatest range of any shark species. Once extremely abundant, over-fishing has caused a worldwide population crash. 

Behaviour:  Spends much of its time in the open sea where it takes advantage of ocean currents to migrate across long distances. Takes advantage of seasonal food supplies such as the annual squid run off the coast of California. 

Reproduction: Viviparous.   

Similar species: The Atlantic sharpnose shark (Rhizoprionodon terraenovae) has a similar long snout and large round black eyes but lacks long pectoral fins and blue coloration. 

Reaction to divers: Usually encountered in baited situations where it can become aggressive. Large blues have been implicated in attacks. Blue sharks outside of baited situations are rarely encountered by divers.