History  Need to mark fish to get survival & exploitation rates for Treaty negotiations, to determine differential survival of various release strategies & to determine distribution in fisheries  Started marking in BC with 1967 brood  Use alpha-numeric tags, mainly on chinook and coho  Use fin clips, mainly on other species except adipose clips on coho

Types of Marking  Coded-wire tags (CWT)  Fin clips: adipose (Ad), right or left ventral (RV/LV), right or left maxillary (RM/LM)  Otoliths (has rings like a scale)  Calcein- fluorescent dye in fins  Passive-induced transponder (PIT) tags

Tagging Pros & Cons  Lots of codes available- can identify different stocks or release strategies  Can get survival and exploitation rates for individual stocks or release strategies  Application is expensive  Recovery may be expensive Fishery sampling is expensive Fishery sampling is expensive Escapement sampling may not be very expensive if at fence or hatchery rack Escapement sampling may not be very expensive if at fence or hatchery rack

Finclipping Pros and Cons  Can use as visual I.D.- for mass marking  Application less expensive than CWT  Few options for distinguishable codes  Can’t get survival & exploitation rates  Higher mortality from ventral/maxillary clips than from tagging  Can’t determine age class if use same clip every year - need scales too

Otolith Pros and Cons  Very inexpensive to apply  No external visual I.D.  Few options for distinguishable codes  Sampling and reading of otoliths is expensive  Can’t determine age class if use same mark every year - need scales too

Magnified Otolith

Number to Tag/Mark  For coho fry, need to tag at least 40K for distribution, 80K for survival & exploitation rates (lower survival on fry release)  Tag minimum 20K coho smolts or 75K chinook smolts for distribution in fisheries  Tag 40K coho or 200K chinook smolts for survival & exploitation  For chum fry need minimum 100K finclips

Costs of Marking  Tags cost $.09 per fish  Contractor AdCWT application costs about $.12 per fish  Adipose clip costs about $.05 per fish  Tagging machines cost about $24,000 for the tag injector and $14,000 for the QCD (checks tag retention)

CWT Recovery Data Availability  Mark Recovery Program (MRP) reports- can get details down to exact sport catch locations and recoveries by week and statistical area for commercial fisheries  SEP1 reports- Summary of fishery recoveries with escapement data added; includes survival & exploitation rates

Tag Recovery Data # Observed  Observed is the number of a particular tag code actually found in a sample of fish in the catch or escapement  # observed in sport catch is # turned in or # found in creel survey  Mark rate is the % tagged in the total sampled

Tag Recovery Data # Estimated  The # estimated accounts for tags in the unsampled part of catch or escapement  Calculated as # observed / sample rate  Sample rate is % sampled of total catch or escapement (100% if all sampled)  Aim for 20% sample rate in commercial fisheries  Use sport awareness factor (creel survey)

Tag Recovery Data # Expanded  The number expanded accounts for the unmarked fish released with a given tag group  It is calculated from the number estimated / number released with tags * total number released (in a given release group)

Example of Estimation and Expansion of Observed Tags  Tag Code (2000 brood Cowichan R chinook): 25,175 tagged of 99,829 total release  Observed in 2003 escapement: 3 tags in dead pitch sample of 527 and total river spawners= 2,494  Estimated= 3/527*2,494= 14  Expanded= 14/25,175*99,829= 56

Information from Tagging/Marking  Identification of hatchery fish  Distribution in fisheries  Enhanced contribution  Harvest or exploitation rate  Survival rate

Identification of Hatchery Fish  For use in brood stock collection  For use in hatchery mark-selective fisheries

Distribution in Fisheries  For interest- to see where a particular stock is caught  Determine what fisheries to close or reduce to help preserve stocks of concern  Determine what stocks are caught in mixed stock fisheries

Chinook Distribution in Fisheries and Escapement,

Coho Distribution in Fisheries and Escapement,

Enhanced Contribution  Determine whether the hatchery component in a river has exceeded some target (50%)  Determine how well the hatchery stock is performing (in conjunction with survival rate)

Harvest/Exploitation Rate  Harvest rate is the % of fish surviving to adulthood caught in one fishery  Exploitation rate is the overall % of fish surviving to adulthood caught in all fisheries  Determine harvest rates in individual fisheries for each stock  Track harvest & exploitation rates to make sure we’re not over-fishing

Survival Rate  Determine differential survival for different release strategies  Determine differential survival for wild versus hatchery releases  Track the trend in survival for warning of any problems developing

Quinsam River Survivals Smolt 0+ and Seapen 0+ (median seapen/smolt = 1.1) Smolt 0+ Seapen 0+

Cowichan Chinook Survival Survival Smolt 0+ and Seapen Brood Year 2 late river 5 seapen