Study: Hatchery Pinks Crowd Wild Sockeyes
- Details
- Category: News
- Created on Monday, 04 March 2024 13:45
- Hits: 487
By NATHANIEL HERZ
Northern Journal
A new analysis of nearly 25,000 fish scales offers more evidence that the millions of pink salmon churned out by Alaska fish hatcheries could be harming wild sockeye salmon populations when they meet in the ocean, according to the scientists who authored the study.
The new peer-reviewed paper, published last week in the ICES Journal of Marine Science, analyzed growth rates that could be deduced from the fish scales, similar to trees’ yearly growth rings.
Pink salmon are seen in an undated photo. (NOAA Fisheries photo)
The paper was built on a unique aspect of the life cycle of pink salmon, which are primarily targeted by commercial fishermen: their abundance is high in odd-numbered years, and lower in even-numbered years. Those booms and busts allowed authors Peter Rand and Gregory Ruggerone to tease out whether sockeye salmon — which are more highly valued by sport and personal use fishermen — were growing at lower rates during odd years, when pink salmon are more numerous.
Their analysis showed that was the case across the Gulf of Alaska — a dynamic that Rand and Ruggerone describe as a “zero-sum game” between the two species. It found that yearly growth of sockeye was depressed by as much as 17% at times when pink salmon abundance was high.
“This is the first time we’ve looked at populations across coastal Alaska, and we see the same signal in all of them,” Rand said in an interview. “It’s quite compelling.”
There’s been increasing debate in recent years about the impacts on other salmon species of growing populations of pink salmon, and Ruggerone last year published a review paper that documented what it called “consistent and strong” evidence of competition. The pinks have been benefiting from warming ocean waters and are also boosted by hatcheries around Alaska that raise them to bolster harvests by commercial fishermen.
The number of pinks returning annually from the North Pacific Ocean rose to nearly 800 million in 2021, up from 170 million in the early 1970s, with hatcheries contributing some 80 million fish each year, the authors wrote in their new study.
Some policymakers, Ruggerone said, have been holding out for more documentation of competition between hatchery pinks and wild salmon, and the new paper should serve as additional evidence, he added.
A spokesperson for the Alaska Department of Fish and Game, whose commissioner has said it’s an “open question” if there’s a relationship between hatchery-raised pinks and wild king salmon populations, said no one was available Thursday to comment on the new study.
––––––––––––––––
Nathaniel Herz welcomes tips at
This email address is being protected from spambots. You need JavaScript enabled to view it.
or (907) 793-0312. This article was originally published in Northern Journal, a newsletter from Herz. Subscribe at this link.
Thanks to the generosity and expertise of the the Central Council of Tlingit and Haida Indian Tribes of Alaska broadband department, Tidal Network ; Christopher Cropley, director of Tidal Network; and Luke Johnson, Tidal Network technician, SitkaSentinel.com is again being updated. Tidal Network has been working tirelessly to install Starlink satellite equipment for city and other critical institutions, including the Sentinel, following the sudden breakage of GCI's fiberoptic cable on August 29, which left most of Sitka without internet or phone connections. CCTHITA's public-spirited response to the emergency is inspiring.
Login Form
20 YEARS AGO
September 2004
Photo caption: A replica of the sign reading “Annahootz Head Chief of the Sitka Tribe” in this 1904 photo of the Kaagwaantaan Wolf House is among items to be rededicated Oct. 23-24 at the 100-year anniversary celebration of the Last Potlatch of 1904. The sign was part of the Wolf House artifact collection loaned to Sitka National Historical Park in 1963.
50 YEARS AGO
September 1974
A seminar course, Topics of Aquaculture will be offered by Sheldon Jackson College. ... Dennis Lund, an SJC aquaculture program instructor, will coordinate the seminar..