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

Leopard shark

• Reported as being more active at night (Manley 1995; Ackerman et al. 2000; Hight and Lowe 2007; Carlisle and Starr 2010; Nosal et al. 2013a)
• In some locations, aggregating sharks may shift habitat use, using warm, shallow water during the day and moving to deeper foraging areas at night (Manley 1995; Hight and Lowe 2007; Nosal et al. 2013a; Nosal et al. 2014)
  • In other locations, sharks may find preferred temperatures and foraging areas in the same habitat and do not show the same daytime/nighttime shift in habitat use (Carlisle and Starr 2010)

Spotted gully shark

• Suspected to be more active at night, based on feeding patterns and catch data (Smale and Goosen 1999)

Leopard shark

• Home range
  • Small home range, but may travel long distances (Ebert et al. 2013)
  • Show strong seasonal site fidelity (Carlise and Starr 2009; Nosal et al. 2013a; Nosal et al. 2014; Carlisle et al. 2015)
  • Warm waters, especially those with low wave energy and little current, appear to attract leopards sharks (during the day); the sharks show daily and seasonal fidelity to these aggregation sites (Manley 1995; Hight and Lowe 2007; Nosal et al. 2013a; Nosal et al. 2014)
  • Manley (1995) observed that nighttime activity spaces for leopard sharks at Santa Catalina Island were, on average, three times larger than daytime activity spaces
• Abundance
  • Occurs year-round in some locations, such as along open coasts of southern California (Smith and Horeczko 2008)
    • May be largely resident in some locations, such as San Francisco Bay (Smith and Abramson 1990; Smith and Horeczko 2008)
  • During spring and summer, the leopard shark is seasonally abundant in bays, estuaries, and some coastal areas; these habitats function as breeding and foraging grounds (Hopkins and Cech 2003; Hight and Lowe 2007; Carlise and Starr 2009; Carlisle et al. 2015, except as noted)
    • In late summer/winter, sharks move out to coastal waters, as water temperatures and salinities change
  • In San Diego/La Jolla, California (Nosal et al. 2014)
    • Females most abundant June-early December
    • Males most abundant late April-early October
• Aggregations
  • The leopard shark aggregates seasonally, through much of its range; sexes segregate—males and females form separate groups (Manley 1995; Ebert 2003; Ebert and Ebert 2005; Hight and Lowe 2007; Nosal et al. 2014)
    • Females tend to use warm, shallow water, particularly during the afternoon; may gain reproductive, growth, metabolic, or digestive benefits (Hight and Lowe 2007; Nosal et al. 2014)
    • Sometimes referred to as “refuging” behavior (Manley 1995)
      • Males and young sharks usually not seen in these areas
    • Groups may form and disappear quickly (Ebert 2003)
  • Fidelity to aggregation sites
    • Some individuals return to the same aggregation site repeatedly, sometimes for multiple, successive years (Nosal et al. 2014; also see Hight and Lowe 2007)
    • Not all individuals show fidelity to particular thermal refuges over time; may use several warm water aggregation sites, if available, or move to other geographic regions (Hight and Lowe 2007)
• Longer-range movements
  • Leopard sharks are highly mobile (Love 1996), but genetic and movement pattern evidence suggests large scale movements are limited (Lewallen et al. 2007; Barker et al. 2015; Carlisle et al. 2015)
  • Known to cross deep channels, such as between mainland California and Santa Catalina Island (Hight and Lowe 2007; Nosal et al. 2014)
  • One leopard shark tagged in San Francisco Bay was recaptured in Santa Monica Bay 10 years later (Smith and Horeczko 2008)
  • Potentially return to the same nursery areas where they’re born (natal philopatry) (Carlisle et al. 2015); limited evidence found by Lewallen et al. (2007)
• Depth usage
  • Usually found on or near the ocean bottom, but appear to use surface waters, at times, as well (Love 1996; Nosal et al. 2016)
    • Also see Aggregations, above
  • Evidence that leopard sharks follow thermoclines (horizontal temperature gradients) while crossing deep water (Nosal et al. 2016)
  • A leopard shark’s sense of hearing may help it determine the depth of a shallow continental shelf (Nosal et al. 2016)
• Navigation
  • Leopard sharks shown to use olfactory cues to navigate in the open ocean (Nosal et al. 2016)
  • Other sensory abilities, such hearing low-frequency noise or detection of geomagnetic cues, may also be important navigational cues (Nosal et al. 2016)
• Influence of environmental factors on seasonal habitat use
  • Nosal et al. (2014) found that surface water temperatures influenced the arrival and departure of leopard sharks to aggregation sites near San Diego, California
    • Movements also influenced by changing daily and seasonal light levels (photoperiod)
• Influence of environmental factors on short-term habitat use
  • Leopard sharks use waters with a range of physical properties (Carlisle et al. 2015)
    • At fine scales, are influenced by temperature, salinity (salt concentrations in water), and dissolved oxygen (oxygen concentrations in water) levels (e.g., Hopkins and Cech 2003; Hight and Lowe 2007; Carlisle and Starr 2010)
  • Tides
    • In bays and estuaries of northern/central California, show strong directional movements with the tides (Ackerman et al. 2000; Ebert 2003; Carlisle and Starr 2010)
      • May swim with the tide to increase the size of their foraging area (also helps save energy) or swim against the tide to stay close to mudflats with abundant prey
    • Along exposed coastlines, tides influence movements between sand flats and rocky reefs (Nosal et al. 2013a)

Spotted gully shark

• Home range
  • Limited data
  • Some individuals recaptured; may suggest some degree of residency/philopatry (in some individuals, at least) (Dunlop and Mann 2014; Soekoe 2016)
  • Some sharks recaptured 15 or more years after first being tagged (Dunlop and Mann 2014)
• Aggregations
  • Often many pregnant females present (Ebert et al. 2013)
• Longer-range movements
  • Dunlop and Mann (2014) report one shark that traveled over 900 km (560 mi)

Leopard shark

• Form seasonal aggregations in shallow water (Love 1996; Hight and Lowe 2007; Nosal et al. 2014)
  • See Movements and Dispersal
  • See Interspecies Interactions
• Often segregate by sex and size (Castro 2011)
• May forage in a loose group (Ebert and Ebert 2005)

Spotted gully shark

• Form aggregations in shallow water during summer (e.g., False Bay and Cape Peninsula in South Africa) (Compagno 2009; Best et al. 2013; Ebert et al. 2013)

Leopard shark

• Actively swim most of the time, but may also be seen resting on sand (Ebert et al. 2013)
• When swimming in shallow water (less than 6 m or 20 ft) along open coasts, tend to swim parallel to shore (Nosal et al. 2013a)
• In an aggregation, sometimes roll upside down (for about a second), exposing pale underside (Klimley 2003; Nosal et al. 2013a)
  • Creates a “bright flash”; possible means of visual communication (Klimley 2003)
  • Exact function unknown; has been observed during schooling and mating (Smith 2005)
• Relationship to humans
  • Timid and harmless; flees when disturbed or startled by snorkeler/diver movements and bubbles (Castro 2011)
  • If provoked, harassed, or hooked by a fisher, will defend itself

Spotted gully shark

• Relationship to humans
  • Harmless (Compagno 1986)

Leopard shark

• Mixed species aggregations: group together with smoothhounds, dogfish sharks, sevengill sharks, and bat rays (Love 1996; Smith and Horeczko 2008)
  • Sometimes forages with these species (Ebert and Ebert 2005)

Leopard shark

• Turning (Porter et al. 2011)
  • A flexible body allows a leopard shark to make tight turns
    • Flex their bodies in different places to make different kinds of turns
  • Use this ability while foraging in narrow tidal creeks and on mudflats, or to escape predators
• Swimming speeds
  • In Elkhorn Slough, about 0.5 kph (0.3 mph), on average (Ackerman 1971; Carlisle and Starr 2010); similar to other bottom-dwelling sharks and rays, including bat rays (Myliobatis californica) and angel sharks (Squatina californica)
  • On Catalina Island, Manley (1995) documented average swimming speeds of 0.11 kph (0.07 mph) during the day and 0.36 kph (0.22 mph) at night
    • Some sharks were stationary for part of the day
  • In open water, Nosal (2016) documented average swimming speeds of 1.8-2.2 (range: 1.3-2.8) kph, or 1.1-1.4 (range: 0.8-1.7) mph
• Conservation of energy
  • Aggregating in calm water may allow leopard sharks to save energy that would otherwise be used to swim against moving water (currents, waves, tides, etc.) (Nosal et al. 2013a)

During summer, female leopard sharks spend many daytime hours in warm, shallow water.

The group of sharks in this aerial photograph are swimming in water only a few feet deep.

Image credit: © Andrew P. Nosal. All rights reserved. Used with permission from the artist.

Image location: La Jolla, San Diego, California