Understanding Harmful Algal Bloom (HAB) Transport Dynamics by Sampling Toxins in Shellfish

These photos are of shellfish sampling which took place at Martinez Harbor in Contra Costa County, California on December 18, 2025. For this study, shellfish traps were baited and deployed for two days in the water before being retrieved. All shellfish were collected, species identified, and individuals measured with calipers. These photos show P. macrodactylus shrimp which is an invasive shrimp found in the region and commonly caught in the USGS traps. Two of their identifying characteristics are their distinct rostrum, which is the pointed horn-like feature on their head and their orange joints. These specimens were all be sent to a laboratory to test their tissue for toxins caused by Harmful Algal Blooms (HABs).