Ningaloo Reef Edge is an important feeding area for four shark and one ray species.

This area is an important feeding assemblage for three species of sharks: Grey Reef Shark, Spinner Shark, and Dusky Shark. These species form assemblages in the area by aggregating to feed on schooling fish. Reports on social media have recorded these feeding aggregations with an average of at least 7 individuals (2–15) together on at least 14 occasions between November–April from 2022–2025. A diver who regularly visits this area 3–4 times per week for seven months each year reports observing these aggregations five times annually between November–April (DT Browne pers. obs. 2025).

Research on Whale Sharks within this area spans decades with diverse methods used to examine seasonal aggregations, demographics, and foraging ecology. Overall, this area has been identified among the 25 largest aggregation sites for Whale Sharks globally (Araujo et al. 2022). Early work used aerial surveys and spotter planes to document seasonal aggregations, while hydro-acoustic surveys and water sampling linked their presence to zooplankton availability. Acoustic telemetry, archival, and satellite tagging later revealed fine- and broad-scale movements, complemented by vessel surveys, and photo-identification to describe population structure, site fidelity, and feeding ecology.

Initial observations of Whale Sharks in 1982, 1983, and 1985 had documented a seasonal aggregation in this area (Taylor 1989, 1994). Later studies established this area as a critical feeding ground for Whale Sharks. Aerial surveys (1989–1992) showed seasonal aggregations along the reef front, where sharks swam mainly parallel to the reef in turbid waters (Taylor 1996). The maximum density in any sector of the reef at any one time was four sharks per km². Their arrival coincided with the annual mass coral spawning after the March–April full moon, when zooplankton levels rise (Simpson 1991; Taylor 1996; Rosser & Gilmour 2008). Hydro-acoustic surveys confirmed Whale Shark associations with frontal zones at reef passages, where zooplankton were concentrated (Wilson et al. 2002). Feeding behaviour was frequently observed, including suction and ram filter feeding, with prey such as coral spawn, the tropical krill Pseudeuphausia latifrons, mysids, and jellyfish (Norman 1999; Taylor 2007). Dense schools of the tropical krill, the dominant krill species in faecal DNA samples, were particularly important prey (Taylor 1996; Wilson et al. 2003a, 2003b; Jarman & Wilson 2004). Chlorophyll-a concentrations were also identified as drivers of distribution, as sharks were often sighted in higher-productivity regions (Sleeman et al. 2007). In 2018, vessel-based acoustic surveys and oceanographic profiling linked Whale Shark space use to prey distribution, showing that sharks concentrated feeding activity along reef gutters and pinnacles where copepods and krill were most abundant (D’Antonio et al. 2024).

Research during the mid-1990s showed Ningaloo Whale Shark aggregations dominated by juvenile males (~600–800 cm total length [TL]; range 400–1,200 cm TL), with ~85% males. Females were rarer and smaller (mean 620 cm TL). Photo-identification (1992–2004) recorded 159 sharks (74% male; 300–1,000 cm TL) and a super-population of ~300–500. In 2018, juveniles remained male-biased (68% of 400; 300–900 cm TL) (Norman 1999; Norman & Stevens 2007; Meekan et al. 2006; D’Antonio et al. 2024).

Photo-identification between 1992–2004 showed strong philopatry; 29% of 159 sharks were resighted within the same year, and 33 across years, typically after 1–3 years, with two after 12 years (Meekan et al. 2006). One shark returned over 19 years (1995–2016). This shows that individuals have repeatedly used this area for feeding across decades (Norman & Morgan 2016). Telemetry studies on Whale Sharks in the area since the 1990s have also confirmed characteristic surface-feeding behaviours and close association with the reef (Gunn et al. 1999; Wilson et al. 2001; Gleiss et al. 2011, 2013). Tour-operator data from 2006–2010 also documented a sharp rise in Whale Shark interactions (350% increase; n = 3,254), showing predictable seasonal aggregations between March–July, with encounters concentrated near reef passages within 3–6 km of the reef crest (Anderson et al. 2014). Fine-scale studies in 2018 revealed that tagged sharks used both surface waters and deeper zones (40–60 m), linking their diving behaviour to mesozooplankton distribution and local oceanographic features (D’Antonio et al. 2024).

Since 2015, ventral photographs of Reef Manta Rays sighted in this area have been catalogued in a photo-identification image database along with metadata such as date and location of sighting (Armstrong et al. 2020; AWJ 2025). Photographs from tourism operators are associated with the peak tourism season (April–September) (Armstrong et al. 2020). The behaviour displayed by each individual when sighted was categorised (following Germanov et al. 2019) and was informed by observations reported by tourism operators or trained observers, or through indications of behaviour evident in the photographs. Between 2015–2020, a total of 152 behavioural observations of Reef Manta Rays were recorded at this area (Armstrong et al. 2020). Feeding was the most common reported behaviour with 79.6% of observations (Armstrong et al. 2020).