California Sea Lion Diet Data from San Clemente and San Nicolas Islands, 1981-Present

Since 1981, the Southwest Fisheries Science Center Marine Mammal and Turtle Division has analyzed sea lion scats and spewings collected seasonally at two Channel Islands rookeries. Otoliths and cephalopod beaks recovered from these samples are used to identify, count, and size the fish and squid consumed by California sea lions. This long-term study provides insights into the diet and foraging ecology of a key marine predator in southern California.

Use Cases

• Modeling seasonal diet variation based on quarterly sample collection mentioned in the description
• Analyzing prey species composition based on otolith and beak identification
• Estimating prey size distribution from otolith and beak measurements
• Comparing foraging ecology between a large and a small rookery (San Nicolas vs. San Clemente Island)

Strengths

• Long-term data collection spanning from 1981 to the present
• Seasonal sampling in winter, spring, summer, and autumn provides temporal resolution
• Data originates from two distinct rookery sites for potential comparison

Limitations

• Column-level documentation is absent; field semantics must be inferred after download
• Row count is unknown, which may limit suitability assessment
• Data format is PDF, which may require extraction for computational analysis

Provenance

Source

National Oceanic and Atmospheric Administration, Department of Commerce

Collection Method

Analysis of scats (fecal samples) and spewings (vomitus) collected at rookeries, with prey identified via otoliths and cephalopod beaks.

Time Range

1981 to present

Freshness

Last updated 2026-03-14 23:06:46.512243; freshness should be verified

Geography

San Clemente Island and San Nicolas Island, Channel Islands, southern California