French Frigate Shoals-Lalo is an important feeding area for two shark species.

Galapagos Sharks commonly feed on Hawaiian Monk Seal Monachus schauinslandi pups mostly during the seven weeks between birth and weaning that commonly occurs in March and April according to direct observations (Johanos et al. 1994; Lowe et al. 2006; Gobush 2010; Baker et al. 2020; Johanos 2020). Beach surveys have been conducted since the early 1980s to monitor seal populations in the North Hawaiian Islands and these data revealed that predation from Galapagos Sharks started to become common in the mid-1990s at Whaleskate Island that held the largest abundance of seal pups (Baker et al. 2020). By 2000, Whaleskate Island was totally submerged and predation increased in Trig Island and started to expand to all other small islands in French Frigate Shoals-Lalo, mostly to East and Gin Islands. Monitoring of 68 Galapagos Sharks tagged with acoustic transmitters between 2008–2010 showed that individuals heavily use shallow lagoon habitats during April around these islands (Blandino 2021). In 2018, Trig and East islands were also submerged but Galapagos Shark predation on seal pups was still observed at the other islands. Between 2018–2019, from 25 dead pups sampled, 16 were due to Galapagos Shark predation (Baker et al. 2020). Galapagos Shark feeding on Monk Seal pups has not been reported for any other of the North Hawaiian Islands and can represent between 15–30% of total mortality for seal pup populations in the French Frigate Shoals-Lalo (Gobush 2010; Baker et al. 2020; Johanos 2020).

Based on direct observations and stomach content analysis (n = 5), it has been reported that Tiger Sharks feed on birds in the area, mostly on Laysan Albatross Phoebastria immutabilis during the fledging season, and this has regularly occurred since the 1970s (Papastamatiou et al. 2006; Lowe et al. 2006; Meyer et al. 2010; Dale et al. 2011; Blandino 2021). Based on acoustic telemetry of 61 Tiger Sharks monitored between 2000–2003 (n = 13) and 2008–2010 (n = 48), individuals were detected at East, Trig, Gin, Round, Shark, and Tern Islands (Lowe et al. 2006; Meyer et al. 2010; Blandino 2021). Tiger Sharks were detected throughout the year, but aggregation clusters and a higher site fidelity was found in shallow lagoon habitats around islands (mainly around East Island) during June and July which overlaps the fledging season for albatrosses (Lowe et al. 2006; Meyer et al. 2010; Blandino 2021). Laysan Albatross use French Frigate Shoals-Lalo as a breeding area from October–July and this is one of the main breeding sites for these species in the Northwestern Hawaiian Islands (Arata et al. 2009). Breeding adults and sub-adults arrive around October to the area and leave it around July along with hatch-year birds. Eggs start hatching around December–January and after one month, adults start to make foraging trips and come back to the area to feed the chicks (Arata et al. 2009). Chick-rearing season runs from February–June when chicks start to fledge (Arata et al. 2009). Predictable shark foraging migrations to the area are consistent with the feeding behaviour reported for the species around the globe and in other areas in the Northern Hawaiian Islands (e.g., Kure Atoll; Heithaus et al. 2007; Werry et al. 2014). Satellite-tagged individuals have shown that some Tiger Sharks leave French Frigate Shoals-Lalo in mid-July when the fledging season is over to areas around the Main Hawaiian Islands, including late-stage pregnant females that go there to pup (Meyer et al. 2010; Papastamatiou et al. 2013).