link to AFSC home page

link to AFSC home page link to NMFS home page link to NOAA home page

Auke Bay Laboratories (ABL)

AFSC Quarterly
Research Reports
Oct-Nov-Dec 2006
ABL Reports
FMA Reports
NMML Reports
RACE Reports
REFM Reports
Quarterly Index
Quarterly Home

Marine Salmon Interactions Program

Pink Salmon Forecast Information Provided to the Southeast Alaska Region

Catch rates of juvenile pink salmon
Figure 1.  Catch rates of juvenile pink salmon, obtained from Auke Bay Laboratories’ Southeast Alaska Coastal Monitoring surveys, are currently being used to forecast adult returns to the region.

ABL researchers presented data and results from the Southeast Alaska Coastal Monitoring (SECM) project and provided adult pink salmon forecast information at the Purse Seine Task Force meeting in Petersburg, Alaska, on 28 November 2006. The task force meeting is an annual event sponsored by the Alaska Department of Fish and Game (ADF&G), the commercial purse seine fishing fleet, fishing industry processor representatives, and other resource stakeholders from Southeast Alaska communities. At the meeting ADF&G scientists presented an overview of the current commercial pink salmon fishing year, and ADF&G and ABL personnel provided forecasts of the pink salmon harvest in the Southeast Alaska region for 2007 (Fig. 1). An accurate forecast has major economic consequences to the industry because it enables processors and fisherman to devote the proper amount of resources to the anticipated harvest, which has an average exvessel value of about $20 million to the region.

ABL is in a good position to make a pink salmon forecast to the region because of a historical time series of biophysical data collected by the SECM Project. Our SECM research, which focuses on juvenile salmon and their associated epipelagic species and oceanographic parameters, occurs from May to August as juvenile salmon migrate seaward to the Gulf of Alaska from southeastern Alaska. From this information, which now comprises a 10-year time series of data, ABL researchers generated a harvest forecast of 40 million pink salmon to the region for 2007. Important parameters used in this forecast are peak monthly average catch-per-haul of juvenile pink salmon and spring ocean temperatures.

In 2006, for the first time, ADF&G scientists incorporated SECM data to improve their forecast, which previously relied exclusively on running averages of past harvest levels. Prior forecasting of pink salmon harvests by ABL researchers, using SECM data for Southeast Alaska, were quite accurate in 2004 and 2005; however, in 2006 the forecast was well above the actual harvest. Possible explanations for the poor returns to the region in 2006 were the anomalously warm ocean conditions observed in the region in 2005 and the presence of unusual competitor and predator species, such as Pacific sardines, Humboldt squid, and blue sharks in the Gulf of Alaska. After the task force meeting, pink salmon forecast information given by ABL researchers was featured in a radio broadcast that aired on Petersburg public radio station KFSK on 8 December 2006.

By Joe Orsi, Alex Wertheimer, Molly Sturdevant, and Emily Fergusson

Evaluating the Effects of Ventral Fin Clips in Marine Survival of Chinook Salmon

The U.S. section of the Chinook Technical Committee of the Pacific Salmon Commission provides funding to evaluate the effects of ventral fin clips on marine survival schedules of Alaska stream-type Chinook salmon. This project will provide information to address concerns over the deterioration of the coded-wire tag (CWT) system as a tool for coast-wide management of Chinook salmon. At the Little Port Walter (LPW) Marine Research Station on lower Baranof Island in Southeast Alaska, ABL researchers have studied two stocks of Chinook salmon since the late 1970s. The research involves two brood years (BY) (2005BY and 2006BY) from the two stocks, originally from the Chickamin River and the Unuk River. The stocks are maintained separately through the use of CWTs.

For the 2005BY, gametes from returning adult Chinook salmon from both stocks were collected, fertilized, and seeded in incubators at LPW in August 2005. In April 2006, the salmon fry were transferred to freshwater vertical raceways. In September and October 2006, a total of 135,107 Chinook salmon (37,144 Chickamin stock and 97,963 Unuk stock) were fin-clipped and tagged with CWTs at LPW.

Two different mark types were applied to 2005BY smolts: 1) adipose fin clip and CWT (66,845 fish), and 2) adipose fin clip, ventral (pelvic) fin clip, and CWT (68,262 fish). For Chickamin River stock, the mean fork length was 107.5 mm and the mean weight was 15.5 g. For Unuk River stock, the mean fork length was 109.7 mm and the mean weight was 17.2 g. After tagging/clipping, the fish were returned to vertical raceways for overwinter freshwater rearing. The 2005BY smolts will be released into the LPW estuary in May 2007.

For the 2006BY, gametes from returning adults of Chinook salmon of Chickamin River stock and Unuk River stock were collected, fertilized, and seeded in incubators at LPW in August 2006. Egg picking occurred in mid-November 2006. Live eyed eggs in good condition numbered 364,441 for Unuk River stock and 205,262 for Chickamin River stock, which should provide adequate numbers of 2006BY smolts (162,000 Unuk River stock and 54,000 Chickamin River stock) for fin clipping and tagging in the second year of this project. In April 2007, the fry will be transferred to freshwater vertical raceways and tagging/fin clipping will occur in September 2007. Three different mark types will be applied to 2006BY smolts: 1) adipose fin clip and CWT, 2) adipose fin clip, ventral (pelvic) fin clip, and CWT, and 3) ventral (pelvic) fin clip and CWT.

The different tag/clip groups will allow determination of the survival differences relative to type of fin clip. These groups will be evaluated for age-specific distribution, exploitation, and hatchery return rates, and cohort reconstruction will be used to determine if mortality schedules are similar between age groups. If the ventral fin clip does not affect distribution or ocean survival after age 2, then it could be an acceptable external mark to estimate stock-age-fishery specific exploitation rates for untagged fish and could be used for indicator stock marking.

By Adrian Celewycz

<<< previous

next >>>

            Home | FOIA | Privacy | | Accessibility      doc logo