Marine Migration of North American Green Sturgeon

Abstract

An understanding of the distribution of North American green sturgeon Acipenser medirostris in coastal waters is crucial to minimize impacts on this vulnerable species from various fisheries. To determine migratory patterns, we tagged 213 subadult and adult green sturgeon in spawning rivers and summer aggregation areas with uniquely coded ultrasonic pingers and observed their coastal movements with arrays of automated hydrophones deployed along the West Coast of North America from southeast Alaska to Monterey Bay, California. Green sturgeon exhibited an annual migration along the continental shelf from U.S. to Canadian waters in the fall and an apparent return migration in the spring. Peak migration rates exceeded 50 km/d during the springtime southward migration. Large numbers of green sturgeon were detected near Brooks Peninsula on northwest Vancouver Island, British Columbia, during May‐June and October‐November. A single fish was detected in southeast Alaska in December. This pattern of detections suggests that important overwintering grounds may be north of Vancouver Island and south of Cape Spencer, Alaska. A high frequency of detection allowed us to estimate that annual survival of tagged green sturgeon was 0.83 in 2004. The rapid, frequent long‐distance migrations by these fish may make them vulnerable to bycatch in bottom trawl fisheries on the shelf waters of western North America.

In situ measurement of coastal ocean movements and survival of juvenile Pacific salmon

“…Only one juvenile BC salmonid was detected on the Alaskan subarray, located some 1,000 km north of QCS, although tagged smolts from the Columbia River and other nonsalmonids were detected there more commonly (21,22). * Steelhead, unlike other species of Pacific salmonids, are thought to move directly offshore (15), so the failure to detect BC steelhead in Alaska may reflect this migration pattern.…”

Effects of acoustic tag implantation on lake sturgeon Acipenser fulvescens: lack of evidence for changes in behavior

“…For example, previous research has not investigated prevalence and duration of surgery effects on behavior after intracoelomic tag implantation in large fish species despite the growing use of acoustic telemetry as a tool for the conservation of sharks (e.g., Carcharodon carcharias; [5]), sturgeons (Acipenser spp. ; [6,7]), and tunas (Katsuwonus spp., Thunnus spp. ; [8]).…”

Estimated Survival of Subadult and Adult Atlantic Sturgeon in Four River Basins in the Southeastern United States

“…Similar approaches have been used to estimate survival rates for Green Sturgeon A. medirostris along the Pacific coast of North America and for Gulf Sturgeon in the Gulf of Mexico and tributary rivers (Lindley et al 2008;Rudd et al 2014). Adult and subadult survival rates are key population parameters, so the availability of comparable but independent estimates from multiple rivers should be very useful in the planning of Atlantic Sturgeon recovery efforts.…”