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Deep Inlet Notice
To Deep Inlet THA Fishery User Groups:
A reminder about boat traffic and anchoring near island homes in the Deep Inlet area.
Please review our plan:
Berry Island Resident Impact and Noise Reduction Plan
UAS Invites Students to Join their Alaskan Aquaculture Semester Program
The University of Alaska Southeast is recruiting students to join their transformative, hands-on Fall semester aquaculture program. It is an adventurous, intensive field semester that provides students with a great opportunity to build regional industry connections and learn exactly what it takes to launch your own ocean farming business.
Please visit the UAS website at this link http://aquaculturesemester.alaska.edu/ to learn more.
NSRAA Board Nominations Open
Attention Southeast Alaska Salmon Permit Holders
NSRAA invites you to nominate commercial fisherman representatives to fill six Board of Director seats that expire in March 2022. See the letter below for full details. The Nomination Form can be downloaded at this link, Nominee Form. You should also receive this form and letter by postal mail. The completed form can be scanned and emailed to scott_wagner@nsraa.org or faxed to (907) 747-1470. These are due by the close of the first day of the fall Board of Directors meeting, 5pm November 18th. We look forward to hearing from you.
NSRAA Initiates Predator Study at Hidden Falls
Marine survival of chum salmon that return to Hidden Falls Hatchery have exhibited a declining trend since the early 1990’s and early predation by rockfish is hypothesized to be the primary cause. In spring 2021, NSRAA took first steps to address the decline by identifying the most prevalent rockfish species and their present and past consumption of hatchery fry relative to other prey at sites where hatchery fish are released. The most numerous rockfish were Black, Dusky, Quilback, and Silvergray rockfish in Kasnyku Bay where the largest chum releases occurred (see tables below) and these same species were most common at the release site near Whitewater Bay, except sculpin replaced Silvergray rockfish in being one of the highest numbered predators.
Catch rates using hook-and-line for the most common species did not significantly change before and during the time when 2g chum fry were released at both sites (see figures below). No change in catch rate was detected near Whitewater Bay when 4g chum fry were released at this site either. However, a significant increase in rockfish catch occurred at Kasnyku Bay during the 4g chum fry release in June. These results match observations that included no visual evidence of predation except when 4g chum fry were released at Kasnyku Bay when rockfish were observed feeding in large schools on chum fry at the water surface. Initial results of stomach contents obtained from captured predators the Alaska Department of Fish and Game permitted for sampling corroborate these findings, as chum fry were in around half the stomachs from rockfish captured on days surface feeding was observed.
Next steps are to conduct stable isotope analyses on tissues sampled from the permitted rockfish species. The turnover rate of stable isotopes in tissues of predators varies between species, fish age and size, and body part sampled, but is generally slow. Therefore, isotope analysis can be used to identify predator diets before capture for comparison to stomach contents at capture to determine if the hatchery releases cause predator shifts in diet. Isotope analysis can tell us this because hatchery fish are raised on fish food that has a unique carbon signature compared to prey in the marine environment, and the difference can be detected in the tissues (liver, muscle, fin, scales), and eye lenses sampled from the captured rockfish. The tissues inform the short term (days to months) prey items and the eye lenses can tell us how often hatchery fish were in the predator’s diet since the predator’s birth. This is possible because the eye lens grows from a core at birth by forming layers with time like an onion. The layers are delaminated and dried and isotope analysis performed as done with tissues to determine if hatchery fish were consumed. The fish whose eye lenses were extracted will also be aged by removing the otolith and counting annuli on it. The otolith nuclei indicates age zero when the lens core is created and the outer lens and annuli represent the fish diet and age at death, so the number of shifts in diet in the predators life can be determined from birth to time of capture.
The proportion of hatchery fish in the predator’s diet controls the carbon signature in the predator’s flesh. The stronger the hatchery carbon signature, the higher the consumption of hatchery fish. However, one factor is that upon release, hatchery fish no longer feed on hatchery food but capitalize on natural prey in marine waters and so gradually lose their unique carbon signature. Therefore, around 1,000 chum fry from each release group were held in an anchored net pen to feed on natural prey drifting into their enclosure. We culled 25 fish for isotope analysis the day before the fish were taken off their hatchery diet and an additional 25 per week were culled for two months to quantify rates the fish’s carbon signature becomes indistinguishable from non-hatchery prey. With this information and the isotope analyses from tissues and eye lenses, we can estimate durations and timings in the captured predators lives that hatchery fish were distinguishable and represented different proportions of their diet.
Results of the stable isotope analyses and study findings will be posted as they are developed.
Wed 9/1 Silver Bay Update
In cooperation with ADFG, NSRAA is opening a portion of the Silver Bay THA to common property seine on Thursday, Sept 1, to harvest fall chum salmon surplus to brood stock needs. This past Saturday a large buildup of Bear Cove bound chum staged in the Sawmill Cove area. NSRAA performed limited cost recovery in Sawmill Cove on Saturday Aug 28th to target a buildup of chum salmon staged near Sawmill Creek. The otolith data of this harvest of 190klbs indicated approximately 75% of those chum were Bear Cove bound fish, with the remainder Deep Inlet origin and overall 91% 3-year olds and 56% male. It appears the bulk of the volume was either harvested or left the Sawmill Cove area and has either moved on towards Bear Cove or backed out towards Deep Inlet. There continues to be some fish staged near Sawmill Creek and there will be no salmon stream restrictions for Sawmill Creek during the opening. This opening is to provide common property opportunity to harvest Bear Cove bound chum salmon surplus to brood stock needs. We will continue to monitor chum returns during the egg take at Medvejie and if brood stock numbers in Bear Cove continue to appear sufficient additional area and openings are likely to occur.
Tuesday 8/24 Update-Crawfish Inlet will open Thursday (8/26) for seine
The NSRAA Crawfish Inlet SHA will open Thursday (8/26) for seine. Openings in the Crawfish Inlet SHA for seine will mirror the Deep Inlet seine rotation with the exception of an hour later start time of 7am. ADFG has determined that it is warranted to open West Crawfish at this time as well and the West Crawfish area will be be open for seine the same days as the Crawfish Inlet SHA. Openings will continue through September 24th, 2021 or unless modified by subsequent ADFG Advisory Announcement. Cost recovery is still ongoing in both West Crawfish and Crawfish Inlet but it is anticipated to be completed on Wednesday (8/25). Most recent sex ratio sample available from Sunday 8/22 was 47% male in West Crawfish.
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