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Abstract The Pismo clam, Tivela stultorum, is an ecologically and economically important species inhabiting sandy beaches and subtidal zones in central and southern California, USA, and northern Baja California, Mexico. This long-lived venerid clam species is of great management, cultural and conservation interest in California where it was harvested for centuries by indigenous people and then nearly extirpated by intense commercial and recreational overfishing in the mid-1900s. A recreational fishery continues today in California; however, T. stultorum faces pressure from poaching, overharvest, and the loss of sandy beaches from rising sea levels and beach erosion. Understanding the susceptibility and resilience of Pismo clams to these pressures is essential for their conservation. We used Pacific Biosciences HiFi long sequencing reads and Dovetail Omni-C proximity reads to assemble a highly contiguous genome of 763 Mb. The genome had a contig N50 of 13 Mb and a scaffold N50 of 38 Mb with a BUSCO completeness score of 95%. Most of the genome sequences (96%) were contained in 19 scaffolds at least 10MB long, consistent with prior evidence that venerid clam genomes are composed of 19 autosomes. This reference genome will enable a more complete understanding of the ecology and evolutionary dynamics of T. stultorum via population genomic analyses, which will help assess risks from climate, fishing, environmental change, and susceptibilities due to life history. Our goal is to better support the continued recovery, informed management and conservation, and future persistence of T. stultorum, a long-lived and highly valued clam species. 

The coastal zone provides foraging opportunities for insular populations of terrestrial mammals, allowing for expanded habitat use, increased dietary breadth, and locally higher population densities. We examined the use of sandy beach resources by the threatened island fox ( Urocyon littoralis ) on the California Channel Islands using scat analysis, surveys of potential prey, beach habitat attributes, and stable isotope analysis. Consumption of beach invertebrates, primarily intertidal talitrid amphipods ( Megalorchestia spp.) by island fox varied with abundance of these prey across sites. Distance-based linear modeling revealed that abundance of giant kelp ( Macrocystis pyrifera ) wrack, rather than beach physical attributes, explained the largest amount of variation in talitrid amphipod abundance and biomass across beaches. δ 13 C and δ 15 N values of fox whisker (vibrissae) segments suggested individualism in diet, with generally low δ 13 C and δ 15 N values of some foxes consistent with specializing on primarily terrestrial foods, contrasting with the higher isotope values of other individuals that suggested a sustained use of sandy beach resources, the importance of which varied over time. Abundant allochthonous marine resources on beaches, including inputs of giant kelp, may expand habitat use and diet breadth of the island fox, increasing population resilience during declines in terrestrial resources associated with climate variability and long-term climate change.