Leopard Shark (Triakis semifasciata) and Spotted Gully Shark (T. megalopterus) Fact Sheet: Diet & Feeding

Leopard shark

• Leopard sharks have a broad diet that varies by location, season, and body size (Smith and Horeczko 2008)
  • Feed opportunistically on benthic (bottom-dwelling), locally abundant prey (Talent 1976; Castro 2011)
• Mainly eat invertebrates, small bony fishes, and eggs of fish and squid (Ackerman 1971; Russo 1975; Talent 1976; Love 1996; Webber and Cech 1998; Ebert 2003; Ebert and Ebert 2005; Smith and Horeczko 2008; Castro 2011; Nosal et al. 2013a)
  • Molluscs: clams, clam siphons, California market squid, octopus
  • Crustaceans: crabs (Cancer, Hemigrapsus, etc.), shrimp
  • Innkeeper worms (Urechis), polychaete worms
  • Bony fishes: anchovies, herring, smelts, croakers, perch, rockfish, flatfish, sculpins midshipmen, gobies
  • Fish eggs (of jacksmelt, topsmelt, and herring)
    • May make up a large proportion of a leopard shark’s diet (Russo 1975)
  • Small sharks and rays (e.g., smoothhound sharks, shovelnose guitarfish, bat rays)
• Large adults (over 100 cm or 39 in) feed mostly on fish (also fish eggs); smaller adults and juveniles eat more crustaceans (especially shore crabs), clam siphons, innkeeper worms, and fish eggs (Ackerman 1971; Talent 1976; Ebert 2003)
• In one study in La Jolla, California market squid (formerly Loligo opalescens, now Doryteuthis opalescens) were the most important component of the diet of leopard sharks (Royer et al., unpublished data; Andy Nosal, personal communication, 2017, unreferenced)
• In one population, Ebert and Ebert (2005) found evidence that adult female leopard sharks make a diet shift after giving birth; hypothesized that this prevents competition with young for the same food resources
• In Elkhorn Slough, thought to have a less diverse diet today compared to the 1970s due to habitat alteration by humans and possible competition with sea otters (Kao 2000; Carlisle et al. 2007)

Spotted gully shark

• Mainly eats crabs, bony fishes, cephalopods (squid/octopus), and other molluscs; rarely small sharks and rays (Sauer and Smale 1991; Smale and Goosen 1999; Compagno 2009; Soekoe 2016)
• Diet is broad; feeding abilities are adaptable (Soekoe 2016)
• Small individuals feed on crustaceans; during growth, diet expands to include bony fishes and molluscs (Smale and Goosen 1999; Soekoe 2016)
  • Larger individuals able to feed on larger bony fishes
  • Smale and Goosen (1999) observed that the diet of spotted gully shark changes with age and size
    • Small spotted gully sharks less than 1 m (3 ft) long mainly fed on Cape rock crabs, Plagusia chabrus
    • Individuals larger than 1 m (3 ft) fed on larger Cape rock crabs and cephalopods (e.g., the reef-dwelling Octopus vulgaris and Loligo vulgaris reynaudi)
    • For individuals larger than 1.4 m (4.6 ft), about half of prey consumed were bony fishes (mainly rocky reef fishes)
    • Sharks and rays are a diet item of larger spotted gully sharks
• Some populations dependent on Cape rock lobsters (Jasus lalandii), after linefish fisheries removed much of the species’ natural bony fish prey (Soekoe 2016)

Leopard shark

• Leopard sharks prey on more mobile prey as they grow in size and gain hunting experience (Lowry et al. 2007)
• Often use quick, sharp movements to capture prey (Ebert and Ebert 2005)
• Bite off the siphons of clams (Talent 1976)
• Suck prey (e.g., clam siphons, innkeeper worms) out of burrows by pressing snout into the mud/sand  (Russo 1975; Talent 1976; Manley 1995; Webber and Cech 1998; Ebert and Ebert 2005)
  • Use body as leverage to pull the siphon/clam out of the mud (Ebert 2003)
  • Larger sharks able to do this more effectively compared to young or juvenile sharks (Ebert and Ebert 2005)
• Suction created when mouth opens; helps pull non-burrowing prey into mouth (Lowry et al. 2007)
• Observed feeding on schooling fish by swimming counter to the direction of the fish, darting into the school with mouth open (Ebert 2003)
• Tidal influences on foraging behavior
  • In bays and estuaries, leopard sharks forage over mudflats with incoming tides; move to deeper water as the tide goes out (Ackerman et al. 2000; Carlisle and Starr 2010; Carlisle et al. 2015)

Spotted gully shark

• Forage along the seafloor on reefs and probably sandy habitat (Smale and Goosen 1999; Soekoe 2016)
• Feed at night when nocturnal prey, such as Cape rock lobster (Jasus lalandii), are active (Smale and Goosen 1999; Soekoe 2016)
• Spawning aggregations of squid may attract foraging spotted gully sharks (similar to some populations of leopard sharks in La Jolla) (Smale and Goosen 1999)
• Teeth used for grasping and/or crushing (not cutting) (Soekoe 2016)
  • During development, teeth shape and size change from being molar- or plate-like (to crush sessile prey) to pointed (to grasp and manipulate swimming prey)
• Lack of bite marks on prey suggests this shark may use suction feeding for pulling prey into its mouth (Soekoe 2016)

A leopard shark's mouth is positioned on the underside of its snout, helping it to feed on prey that live in the sand or mud.

Also note the nostril flaps ("nares") that direct water into the shark's nose and enhance its sense of smell.

Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved. Note: This is a cropped image.