PROJECT HIGHLIGHT:
This project is evaluating the potential for commercial cultivation of native Pacific littleneck clams in the Morro Bay Estuary in an effort to help expand shellfish production beyond the non-native Manila littleneck clam. Viability of the species is being determined by directly comparing the native Pacific littleneck with the non-native Manila littleneck clam in both field and laboratory trials.
PROJECT SUMMARY:
California ranks 10th in the U.S. for shellfish production, with most efforts focused on the cultivation of oysters, abalones, mussels and clams. Despite the industry’s substantial economic significance, shellfish hatcheries and farms regularly experience disease outbreaks and suffer stressors due to warmer oceans. One promising strategy for increasing the industry’s resilience and mitigating current and future disease threats is to integrate native species into shellfish aquaculture cultivation.
In order to expand sustainable shellfish practices in California, many growers are pursuing cultivation of native species. This interest stems from both the environmental and social benefits associated with cultivating native species, as many can have both commercial and conservation impacts. The native Pacific littleneck clam (Leukoma staminea) is a species that is highly sought after in recreational fisheries, and is of interest to multiple California commercial growers. While there is commercial potential for this species, there are concerns associated with the survivability and shelf life of these clams that may limit long-term commercial success.
This project is testing whether planting native littleneck clams (L. staminea) at higher tidal elevations can improve post-harvest survival during storage and shipping, easing the economic vulnerability of shellfish farmers while fostering their participation in the recovery of a species that has experienced decades of decline. Documenting the viability of native littleneck clams can provide farmers with the confidence they need to commit to purchasing commercial-scale quantities of native seed from hatcheries. Expanding shellfish aquaculture to include a local, native species facing population decline will also boost the ‘social license’ growers need to maintain their industry.
Researchers have, as of early 2025, outplanted native littleneck clams and Manila clams at two tidal heights in Morro Bay and deployed clams in experimental bags to monitor growth and survival. Baseline physiological trials have assessed species tolerance to air stress, helping predict shelf life. One early result is that Manila clams survive nearly twice as long as littleneck clams in cold storage. Larval culturing will be completed in the summer of 2025.
Kevin Marquez Johnson