Wednesday, November 8, 2023

Ships Killing Bay Sturgeon

This sturgeon’s tail was cut off in a likely vessel strike. 
Bay Bulletin, Endangered Atlantic Sturgeon Threatened By Ship Strikes In Busy James River
Early 2024 will mark 20 years since the first evidence came to light that Endangered Atlantic sturgeon, believed to be wiped out in the James River, were still spawning there.

The Rice Rivers Center at Virginia Commonwealth University (VCU)has been keeping a close eye on the river’s stock of these “living fossils”, which haven’t changed much since they swam around in the time of the dinosaurs.

As the 2023 fall spawning run wraps up, Chesapeake Bay Magazine talked with the
Center’s sturgeon expert Dr. Matt Balazik about a concerning trend that parallels a larger issue with endangered whales along the Atlantic coast: vessel strikes. In Balazik’s latest update from Nov. 4, he notes, “Lots of ship strikes are being reported.”

Researchers count on citizen scientists to gather information about possible vessel strike victims they find and even salvage the fish carcass for study. Balazik says, “Data suggest that relatively there are a lot of carcasses floating around right now so please keep a lookout and report your discoveries.”

The ship strikes on adult (spawning age) sturgeon have been concerns for years. The James has considerable traffic, from U.S. Navy vessels around Hampton Roads to bulk carriers visiting Hopewell and multiple tugs pushing barges as far up as the Richmond Intermediate Terminal. While sturgeon hug the bottom when at rest and feeding, they swim 4-5 meters (13-16’) deep, just about the depth of many vessels’ large, powerful, slow-turning propellers.

Odd as it may seem, the VCU team has been placing ultrasonic tags in carcasses to see how they drift, in order to begin assessing how many sturgeon get hit each year. It’s a difficult research problem, but it’s important to gain mortality insight about a fish that can spawn for decades—unless its life is cut short.

VCU has implanted more than 200 ultrasonic tags on sturgeon during a catch and release process. The ultrasonic markers “talk” for up to ten years each to several coordinated arrays of receivers up and down the Atlantic coast. Researchers caught a sturgeon this fall that was tagged on Oct. 11, 2013. They say the battery in his tag should die any day now.

So, why didn't they swap out the battery, or at least retag the fish. 

The Wombat has Rule 5 Sunday: One Last Glimpse Of Bikini up at The Other McCain.

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