Project Objectives

• The purpose of this project is:
• 1st- to estimate the number of salmon smolts being consumed by Northern Pike Minnows within the Lower Yakima River
• 2nd- to develop an Index of Catch Per Unit Effort for relative abundance measures.
• Lastly, to track movement of NPM that have been pit/radio tagged in our sections

Consumption data

• During tagging, every 5th fish is sacrificed so that stomach contents may be taken and examined for fish and insect proportions.
• Preliminary in field “estimates” are made by eye, to determine the ratio of fish to invertebrate in the stomach.
• Further examination by microscope will be conducted at the lab to retrieve more accurate determination of species in gut.

Removal of stomach for analysis

Removal and storage of stomach contents.

Analysis of contents via stained hard structures

Identification to species

2004 Stomach Contents

2005 Juvenile Passage Data

Catch Per Unit Effort: Developing an Index of Relative Abundance

Why use an index?

• Usually considered a “short cut”
• Less expensive
• Less time consuming
• Other methods such as “Peterson mark- recapture fail to provide valid estimates

Slide 12

Slide 13

What factors can effect CPUE?

Environmental and Biological Factors include:

• Conductivity
• Turbidity
• Flow **
• Weather
• Temperature
• Need to protect adult Spring Chinook from electro fishing damage (= loss of NPM due to premature recovery from stun affect)

Slide 16

River Flow Above Parker dam (Sunnyside dam), taken near Umtanum

River Flow below Parker dam

Comparison of current water year with previous and average water years at Parker.

CPUE Total for March 25th - May 24th 2004

Catch per Unit Effort for March – June 1, 2005

High water Period Below Dam 2004

Low Water Period Below Dam due to water withdrawal 2004

Tracking Movement

• Fish are collected and marked in pool habitats within 1-mile sections, separated by 2-mile buffers (total of 9 sections)
• Entire reach from Naches River confluence to Toppenish Creek(33.3miles) is shocked to track movement between sections
• Shocking schedule:
• *Once a Month in Spring
• *Once in Summer
• *Once in Fall
• *Once in winter
• This year starting April 1, 20 radio tags were placed on fish caught throughout the various sample sections. The lifespan on these tags is 390 days at 4 second intervals, and should yield additional information we could not get with shocking of pit tagged fish.
• ** i.e.- tributary migrations

Tag methodology: External attachment of tag on left side of dorsal fin

Tag is anchored on right side of fish with a plastic saddle

The end result- tag lies on the side of the dorsal resulting in minimal damage to the fish

Tracking of radio tags

Locations of tags 79-89

Locations of tagged fish

• For the May 21 tracking, tags 82 & 85 where found in the same section and pool they were tagged in.
• Radio tags 79,80,84,86,87,88,89: these tags were found very close to original pools where tagging occurred. In only 2 cases did fish move, #79 moved 1383 meters upstream, and #84 also moved about 1453 meters upstream.

Movement: more questions created than answered….

• Fish often stay put, with a predisposition to stay in pools where they were tagged.
• Anomaly seen: often, tags disappeared for periods of time from the main stem, only to suddenly reappear a few days later.
• Question: do they disperse to tributaries during low water events, and if so, which ones?

Conclusions

• Consumption: still pending, but salmon smolts have been found in larger NPM.
• CPUE: Depends on several factors, but prey presence/absence and river flow (Q) seem to effect this index the most.
• Movement: Northern Pike Minnow seem to be site tenacious for the most part, but this is highly dependent on water levels. Radio tagging has revealed that many tags disappear when water levels drop, only to reappear suddenly with water increase. This may be an indication of tributary usage during lower flows. Aerial flights are planned to help reveal these movement patterns.

Acknowledgements

• Many thanks to Joe Jay Pinkham and Linda Lamebull for tireless determination and patience while in the field.
• Special thanks to USACE Bob Wertheinmer for introduction to radio tag attachment methods and technical support.

Questions