Mysids of the Salish Sea

Abstract

The resilience of marine life is increasingly challenged by environmental changes. Due to exploitative fishing practices, urbanization along coastal regions, and other pollutive human actions , the structural and functional features of our marine environments have been sacrificed. At this accelerated rate of habitat loss, methods of fast and efficient bio monitoring are greatly needed in order to protect our marine ecosystems. Biodiversity assessment of marine zooplankton are beneficial for understanding environmental changes within marine ecosystems, as they play a crucial role in the pelagic food web and are rapid responders to ecological change. To gather information on biodiversity within the Salish Sea we performed a plankton tow on June 28th, 2025 around 1330 , located at the dock at Friday Harbor Laboratories (FHL). This was followed by another plankton tow shortly after dusk , at approximately 2300, which was compared to our daytime samples. These plankton samples were split into two divisions, half were sent for traditional environmental DNA (eDNA) metabarcoding and the remaining half were hand sorted to identify unique morphospecies. As an extension of this metabarcoding project, I carried out a species focused project on identification of the order Mysida. There are approximately 1200 documented species of mysids currently , often under sampled in traditional methods of DNA barcoding. Mysid specimens were collected sole ly from the night time plankton tow. Given their horizontal and diel migration patterns , they are less likely to be found in day time plankton sample s. Two morphologically different species of mysids were photographed using compound microscopy and sent for DNA sequencing. Elev en specimens were preserved in 95% ethanol and mounted for scanning electron microscopy. SEM was utilized to uncover diagnostic features, with the aim to identify each individual species. Specifically looking for spines on the antenna! scale, telson morphology , and statocysts. Due to beam alignment malfunctioning on the NeoScope JCM 5000, electron microscopy images were limited given these recurrent maintenance issues. This unfortunately led to poor image quality , leading to an inability to ID the mysid specimens. Nonetheless biodiversity assessments of marine zooplankton are essential, as they remain significantly underdocumented. Despite the long history of zoological research and routine DNA barcoding at FHL, prior DNA barcoding efforts revealed over 47% of daytime plankton samples were not barcoded. Given the significance of zooplankton for understanding environmental changes within marine ecosystems, eDNa serves as a powerful tool for non-in vasive biodiversity assessments.