true

ISRA FACTSHEETS

NORTH AMERICAN PACIFIC

ISRA FACTSHEETS

NORTH AMERICAN PACIFIC

Santa Monica Bay ISRA

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Santa Monica Bay ISRA

Santa Monica Bay

Summary

Santa Monica Bay is located in southern California, United States of America. This split area is situated in the Southern California Bight. The habitat is characterised by the presence of sandy beaches, low-relief rock reefs, small creeks, and small harbours. Within this area there are: threatened species and reproductive areas (White Shark Carcharodon carcharias).

Santa Monica Bay

Santa Monica Bay

DESCRIPTION OF HABITAT

Santa Monica Bay is located in southern California, United States of America (USA). The area is situated in the Southern California Bight, in Los Angeles County. It is a split area that extends in the south from Redondo Beach to Marina del Rey and from Carbon Beach to Malibu in the north. The area is characterised by the presence of sandy beaches, low-relief rock reefs, small creeks (e.g., Ballona Creek), and small harbours along the coastline.

The area is influenced by the California Current, a surface current carrying water equatorward along the North America coast and is characterised by low temperatures, low salinities, and high dissolved oxygen (Lynn & Simpson 1987). Local surface winds, coastal upwelling during the boreal spring, surface heating, and topography produce high variability in stratification, thermocline depth, and micro-scale cells of water (Di Lorenzo 2003).

This Important Shark and Ray Area is benthic and pelagic and is delineated from inshore and surface waters (0 m) to 10 m based on the bathymetry of the area.

CRITERION A

VULNERABILITY

One Qualifying Species considered threatened with extinction according to the IUCN Red List of Threatened Species regularly occurs in the area. This is the Vulnerable White Shark (Rigby et al. 2022).

CRITERION C

SUB-CRITERION C1 – REPRODUCTIVE AREAS

Santa Monica Bay is an important reproductive area for one shark species.

Data from fishery catches, satellite and acoustic telemetry monitoring, unmanned aerial vehicle (UAV) surveys, and environmental DNA (eDNA) surveys have confirmed the regular presence of White Sharks in the area (Lowe et al. 2012; Anderson et al. 2021; Rex et al. 2023; McCauley et al. 2024; Merson et al. 2025). These indicate that southern California contains spatiotemporally dynamic centres of primary and secondary nursery habitat for young-of-the-year (YOY) and juvenile White Sharks. Juveniles form aggregations at locations that are inter-annually variable along the coast, with individuals exhibiting increased site fidelity, residency levels, and spatially restricted movements for periods up to eight years (Anderson et al. 2021). Santa Monica Bay represents one of the largest and interannually active sites on the California coast where YOY and juvenile White Shark aggregations are regularly and predictably observed (Lowe et al. 2012; Anderson et al. 2021; Rex et al. 2023).

Catch data from multiple fisheries operating in nearshore waters between 1936–2009 revealed that the broader area of the Southern California Bight is a nursery area for White Sharks (Lowe et al. 2012). Of 369 records, 39% (n = 144) were neonate/YOY measuring <175 cm total length (TL; Cailliet et al 1985; Malcolm et al. 2001), 21% (n = 77) were juveniles, 5% (n = 18) were adults, and the rest were of unreported size. Inside the Southern California Bight, Santa Monica Bay was identified as a hotspot for catches of YOY and juvenile White Sharks especially during the summer (Lowe et al. 2012).

Between 2010–2026, the California State University – Long Beach (CSULB) Shark Lab tagged 378 White Sharks across southern California. Of these, 40 (10.6%) were neonate (<150 cm TL; Ebert et al. 2021), 61 (16.1%) were YOY, and 243 (64.3%) were juveniles at the time of tagging (CSULB Shark Lab unpubl. data 2026). In Santa Monica, seven YOY White Sharks were tagged with tagging effort being lower here compared to other areas across the California coast. However, 98 YOY and juvenile White Sharks tagged in other locations have been detected 222,024 times from 2010 to 2026 highlighting the area as a hotspot for these early life-stages (CSULB Shark Lab unpubl. data 2026). In addition, UAV survey data between 2011–2025 revealed the regular presence of aggregations composed of up to 15 individuals (YOY and juveniles) present at one time and confirmed from acoustic telemetry (Rex et al. 2023; CSULB Shark Lab unpubl. data 2026).

Santa Monica Bay

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