Steelhead Archival and Acoustic Tag Project

Objective 1

Capture and tag out-migrating post-spawn steelhead kelts, Kenai Peninsula, Alaska. 

Map of Study Area: Kenai Peninsula, Alaska

This study focuses on three geographically proximate streams and the near-shore environments at the mouths of these streams on the Kenai Peninsula, Alaska.  The mouths of the three streams are located within 56 km of coastline and all drain into Cook Inlet.  The Alaska Department of Fish and Game (ADF&G) operates a weir on the Ninilchik River where they capture an average of 280 out-migrating steelhead kelts.  Extensive sport fisheries for steelhead occur in the Anchor River and Deep Creek.  In the Anchor River, over 20% of steelhead are repeat spawners.  Although, fish will not be captured and tagged in the Anchor River during the first two years of this study, tag recovery may occur in recreational fisheries in this river.

Through a cooperative agreement with ADF&G, the USGS will operate the weir on the Ninilchik River from May through June (2002-2004) to capture out-migrating steelhead kelts.    Steelhead kelts in Deep Creek will be collected with hook-and-line or seine.  Our 2002 objectives are to tag sixty steelhead kelts at the Ninilchik River weir and 15 steelhead kelts from Deep Creek.  Fifty fish will be implanted with acoustic tags and 25 fish will be implanted with archival tags.  The acoustic and archival tags will be surgically implanted using techniques which have been refined to minimize mortality and stress.  All fish will be double tagged with PIT tags at time of surgical implanting.  The use of PIT tags will enhance the identification and re-capture of returning tagged kelts.

             The ADF&G Ninilchik River Fish Weir With Up and Down Stream Traps

In the spring of 2002, 50 adult steelhead on the Ninilchik River were tagged with V8SC coded acoustic pingers manufactured by VEMCO.  The cylindrical acoustic tags are 30 mm long and 9 mm in diameter. The tags are programmed for a random pulse interval between 30 and 90 seconds and, with a lithium battery, will have a life expectancy of 125 days.  All tags will transmit at the same frequency (69 kHz) and unlike conventional acoustic tags that transmit a single ping, coded acoustic tags transmit a burst of 6 pings followed by an off time interval.  The burst of 6 pings encodes an identification number that can be decoded by a receiver and stored into non-volatile memory.  The duration of the off time interval is programmed to vary randomly about 10%, thus the pulse from multiple tags will only overlap briefly.

LOTEK type LTD_1110 archival tags (below) were implanted in 25 steelhead kelts.  The tubular archival tags are 32 mm long and 11 mm in diameter and are equipped with an external inactive light stalk.  The LTD_1110 archival tags record temperature and pressure for up to 24 months.  The data is stored as overlapping non-volatile memory.  In addition,  8 beta type LTD_2410 archival tags were implanted into steelhead kelts.  The LTD_2410  is equipped with an external active light stalk and collects temperature, pressure and ambient light data for 24 months.  The archival data collected will be used to provide inference on preferred marine habitat and migration patterns of steelhead in the North Pacific.

     LOTEK LTD_1110 Archival Tag Used For Collecting Fish Habitat Data

Click on thumbnails for larger versions of the pictures below

Inserting archival tag	An archival tagged steelhead with external light stalk	Taking scales for aging tagged steelhead

(continued to Objective 2)

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