Sockeye, but not kings

Sonar can tell us when it sees a fi sh, but not 14 whether that fi sh is a sockeye or a king 15 salmon. Because more than 95 percent of the salmon that migrate past the site are sockeye 13 11 we can generate useful estimate data while 12 5 6 1 2 9 counting all sonar-detected fi sh as sockeye. 4 7 8 3 This is not the case for king, which trickle into 10 the in very small numbers alongside droves of sockeye. ADF&G Sonar Sites 6. Crescent 11. Yukon (Pilot) 1. Kenai (RM 8.6) 12. Aniak 2. Kenai (RM 19) 7. Nushagak 8. Kvichak 13. Anvik 3. Anchor 14. Sheenjek 4. Kasilof 9. Copper Copper River Sonar Site 10. Chilkat 15. Yukon (Eagle) 5. Yentna – Miles Lake – How Biologists Use Sonar to Generate Estimates When we operate Sonar site operations begin about the middle of May and usually end July 31. Sonar site Copper River Sonar Site–Miles Lake crew begin operations as soon as possible, sometimes snowmachining equipment to the site and chipping through shore ice to deploy the sonar transducers.

Alaska Department of Fish and Game Division of Commercial Fisheries PO Box 669, Cordova, AK 99574-0669 Fisheries biologist, Steve Moffi tt: (907) 424-3212 steve.moffi tt@.gov For more information on the Have a question, Copper River sonar site and other comment or Alaska Department of Fish and suggestion? Please Game fi sheries sonar sites visit: contact us by phone, www.AlaskaFisheriesSonar.org e-mail or snail mail.

This project was partially funded under award NA08NMF4380597 from NOAA Pacifi c Coastal Salmon Recovery Funds administered by the Alaska Department of Fish and Game, Alaska Sustainable Salmon Fund. Why doesn’t the sonar site… Run sonar continually? Ensonify the middle of the river? Sockeye salmon runs pulse into the Copper River cloaked behind turbid glacial melt water. To The difference in estimates generated while At the Copper River site, sockeye salmon don’t gauge sockeye runs we can’t see we have taken operating sonar continually and estimates swim up the middle of the river. The river’s a lesson from one of Mother Nature’s fi sh-fi nding generated by sampling is very small. But the exceptionally strong currents push sockeye close to experts. Many toothed whales fi nd fi sh by emitting difference in operational costs is huge! Instead of shore, where it takes less energy to swim upstream. high-pitched calls and listening for returning operating sonar continually, we record 10-minute snapshots hourly, which we then expand to echoes. Similarly, we have adopted sonar as a How close to the banks do fish swim? represent a full 24-hour period. tool to detect Copper River sockeye not by sight, 90% swim within... but by sound.  33 ft. 65 ft. 

Site sonar technology South North At the Copper River Bank Bank site we detect fi sh The Copper River is 1,180 ft. wide using a type of   sonar technology known as DIDSON. Where the site is located A boat-mounted survey of the middle of DIDSON is the latest the river found fi sh were all but entirely generation in fi sheries The sonar site is located below the Million Dollar Bridge absent beyond the range of the DIDSON sonar and records between the Childs and Miles Lake Glaciers and approximately transducers. video of migrating 33 miles upstream of the mouth of the Copper River. salmon similar to images produced with ultrasound in hospitals.

Gult of Alaska