7/9/2023 0 Comments Water column geo duckThis species is also long-lived, the oldest individual on record being approximately 168-y old (Bureau et al. It is the largest infaunal clam in the world, growing up to 3.25 kg whole weight and living up to a meter below the sediment surface (Goodwin & Pease 1987). It lives in the low intertidal zone and subtidally as deep as 110 m, buried in sand, silt, and gravel (Goodwin & Pease 1989, Bureau et al. The Pacific geoduck clam Panopea generosa (Gould, 1850) is distributed from Alaska to Baja California (58-28 N) (Bernard 1983). KEY WORDS: benthic impact, eelgrass, geoduck, clam, harvest, Panopea generosa This study indicated little effect of commercial geoduck harvesting practices beyond short-lived resuspension of sediment on the two harvested plots. In addition, no significant response in eelgrass parameters was observed. No changes were observed, however, in any of the measured sediment or infaunal variables on or near the harvested plot or in adjacent eelgrass. Suspended sediments were increased by harvesting, but generally limited to the footprint of the harvested area, and were not greater than those created by wind/storm conditions. Sedimentation rates during harvesting were examined and compared with those of natural occurrence. Eelgrass parameters studied included shoot length, shoot density, and biomass. Sediment and infaunal qualities examined included: grain size, percent organics, total nitrogen, total organic carbon, sulfide content, redox potential, and infaunal community structure. Harvest of the subtidal plot occurred at one year and mock harvest of the intertidal plot occurred after one preimpact sample. Sediment samples were collected inside the impacted plots and at intervals up to 75 m away while eelgrass samples were collected adjacent to the impacted plots and at intervals up to 50 m away, seasonally over 2 y. The present study was conducted on one intertidal and one subtidal plot to assess potential effects of commercial-scale geoduck harvesting on the sedimentary benthic environment and nearby eelgrass beds. This type of disturbance could have significant effects on the local benthic environment, but has been little examined. To extract these clams, harvesters use pressurized water jets to dislodge surrounding sediments. ABSTRACT The Pacific geoduck Panopea generosa is the largest burrowing clam in the world and adults can live up to a meter below the sediment surface.
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