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Program Element

       Name of study: Striped Bass Summer Abundance Survey (Townet Survey)
 
       Program manager
              Name:    Donald E. Stevens
              Agency:  California Department of Fish and Game
              Address: 4001 N. Wilson Way
                       Stockton CA 95205
 
              Phone: 209-948-7800
 
       Purpose/Objective:
               Measure annual spawning success and evaluation of factors
               affecting abundance and distribution of young striped bass.
 
       Geographic range of field work:
              San Pablo Bay/Suiun Bay/ Delta to RioVista and Stockton.
       Number of sites:
               Currently there are 31 sites.  However others have been
               dropped and added over the years as described unde comments.
       Period of record (Start year): 1959-1996.
               In 1966 no abundance index was obtained because no boat was
	       available to sample with.  In 1983 no valid index was	
               obtained due to high flows flushing the population outside
               of the sampling area.
 
       Size for complete data base for program element in KB (MB):
              Catch files in SAS are 6.2 MB;  The length file in SAS is
              10.5 MB.
       Number of individual files:
              Currently there is one length data file and one catch data
              file for years of record 1959-1996.
 
       Sample frequency per time unit (second, week, month):
              Surveys are conducted at two week intervals starting in June
	      or early July and ending when the average size of striped
	      bass in the catch is 38.1 mm or greater.
       General category of data collected (e.g., media, flow, physical, 
	      common chemicals, metals, pesticides, nutrients, 
              chlorophyll, fish, invertebrates, or phyto/zooplankton):
              Data at each site is collected on the first tow for:
 	      secchi(since 1969; some missing in 1969); specific
	      conductance (since 1969); temperature (1970, 1973 to
	      present). Catch of striped bass for each tow( all years);
              catch of other species for each tow (all years except
       	      1967,1968).  Lengths of striped bass (all years); lengths of
	      other species (collecteed since early 970's) on a consistent
              basis.
 
       Comments about element (e.g., idiosyncracies, changes over time, 
              special events, etc.): Stations were added and dropped in
	      1961.  This changed the water volume weighting factors used
	      to calculate the striped bass abundance index.  These changes
              are found in: Chadwick, H. K. 1964.  Annual abundance of
              young striped bass, Roccus saxatilus, in the Sacramento-San
	      Joaquin Delta.  California Fish and Game 50(2): 69-99.
 
Field Sampling
       Gear type or field instrument used:
              A towed net on skiis is used.  The area of the net mouth
	      opening is 1.51 m2... A complete description of
              specifications is found in: Miller, Lee W. 1977.  An
              evaluation of sampling nets used for striped bass and
              Neomysis in the Sacramento-San Joaquin estuary.  Anadromous
    	      Fisheries Branch.  Administrative Report No. 77-3.  29 p.
              Brief description of sampling procedure, including
              sub-sampling, sorting, identification of organisms  (this 
              should include procedures for transport of sample from field
    	      to lab):
 
              Three 10 minute tows are made at each sampling site 
              except two tows only are made if the striped bass catch
              is zero on the first two tows.  Tows are made against 
	      the current.  All striped bass caught are currently 
	      measured to the nearest mm (original measurements were
              made in tenths of inches).  A subsample of the other 
	      species caught are measured.  All fish caught are 
	      identified and enumerated on the field form.
       Reference to any written protocols and how to obtain a copy:
              A copy of the townet survey protocol can be obtained upon 
	      request to the project manager.
       Changes in gear or procedures which affected the data over time:
              Site number 340 has not been sampled for all years and has 
	      not been included in the abundance index calculation.  
	      Changes from cotton to nylon netting occurred in 1969.  An 
	      evaluation of paired tows with the two nets revealed no 
	      differences in relative efficiency of the two materials.  
	      Another change will need to be evaluated in the future 
	      because both the bobbinet in the cod end and the stretched
              mesh netting in the front end can no longer be purchased.  
	      Suitable substitutes have been located.
 
Laboratory analysis - Chemical
       Name and address of laboratory(s) running analysis:
 
              Current since (date):
              Historical lab (if known) or reference to other documentation:
 
       Analytical methodology for each parameter or group of parameters:
 
       Reference to table which lists detection limits for each parameter:
 
              Current procedure since (date):
              Historical procedures (if known) or reference to other 
	      documentation:
 
       Quality assurance/control (QA/QC) protocols (if brief) or one-line 
	qualifier:
 
       Reference to any written QA/QC protocols and how to obtain a copy:
 
Laboratory analysis - Biological
       Name and address of laboratory(s) running analysis:
              Bay Delta and Special Water Projects Division
              4001 N. Wilson Way
              Stockton, CA 95205
 
              Current since (date): 1969.
              Historical lab(if known) or reference to other documentation:
                     Previous to 1969 work was done by Inland Fisheries 
		     Branch in Sacramento.
       Methodology for each analysis:
 
              Current procedure since (date): NA
              Historical procedures (if known) or reference to other 
	      documentation:
              NA
       Reference used for identification of organisms:
              Miscellaneous field guides:
              Kimsey J.B. and Leonard O. Fisk 1960. Keys to the freshwater 
	      and anadromous fishes of California. California Fish and 
	      Game(46(4):453-479.
              Miller, D. J. and R. N. Lea.  1972. Guide to the Coastal 
	      Marine Fishes of California.  California Fish  Bulletin 
	      Number 157: 249 p.
 
       Location of reference collection (if one exists):
              None
       Reference to table listing scientific name, common name (if any), 
       and code used:
              Table of codes and names to be included with format of files.