Annual Report:

Juvenile fish monitoring during the 2014 and 2015 field seasons within the San 

Francisco Estuary, California

Todd Miller, Denise Barnard, Jonathan Speegle, Jessica Adams, 

Catherine Johnston, Julie Day* and Lori Smith

U.S. Fish and Wildlife Service

Lodi Fish and Wildlife Office

Delta Juvenile Fish Monitoring Program

850 South Guild Ave, Suite 105

Lodi, CA 95240

(209) 334-2968

October 2017

*Corresponding author: 

julie_day@fws.gov

U.S. Fish and Wildlife Service
ii

EXECUTIVE SUMMARY

The Delta Juvenile Fish Monitoring Program (DJFMP) has monitored juvenile Chinook Salmon 

Oncorhynchus tshawytscha within the San Francisco Estuary (Estuary) since 1976 using a 

combination of surface trawls and beach seines. Since 2000, three trawl sites and 58 beach seine 

sites have been sampled weekly or biweekly within the Estuary and lower Sacramento and San 

Joaquin Rivers. The objectives of the DJFMP Annual Report for the 2014 (August 1, 2013 to 

July 31, 2014) and 2015 (August 1, 2014 to July 31, 2015) field seasons were to (1) report water 

quality information collected concurrently while monitoring fish during the 2014 and 2015 field 

seasons, (2) document the fish assemblage structure at monitoring sites, (3) determine the 

abundance and distribution of naturally and hatchery produced juvenile Chinook Salmon 

migrating into and out of the Delta, (4) document the length frequency distributions of unmarked 

juvenile Chinook Salmon captured, and (5) discuss how the relative abundance indices of 

unmarked winter-run sized or older juvenile Chinook Salmon occurring near Sacramento 

informed real-time Delta Cross Channel (DCC) water operation decisions. 

Environmental parameters. We generally observed high variation in water quality parameters 

across all trawl sites and seine regions. We observed slightly higher water temperatures in 2015

than in 2014, frequently exceeding 25°C in the summer months of both years. We also observed 

highly variable dissolved oxygen values in the lower San Joaquin River during the 2014 field 

season, which decreased to <3 mg/L during the winter, and increased to above 12 mg/L in the 

spring months. In general, turbidity was lower within the Central Delta and South Delta seine 

regions relative to other regions throughout most of the field seasons. Little distinct inter-annual 

patterns were observed in water conductivity in trawl sites or seine regions. Despite small 

variations in water temperature and conductivity between the 2014 and 2015 field seasons, there 

was a strong contrast in seasonal flow regimes between the two years. The 2014 field season was 

characterized by low variation in seasonal flows and a near absence of strong peak flow events in 

fall and winter months in comparison to 2015. 

Fish assemblage. The fish assemblage was dominated by nonnative resident fish, and there was 

an overall decrease in fish captured during the 2015 field season compared to 2014. In general, 

anadromous-pelagic-nonnative species dominated at Chipps Island and resident pelagicnonnative fish dominated at the Mossdale Trawl Site. In contrast, anadromous-pelagic-native 

fish were relatively more abundant at the Sacramento Trawl Site. The mean yearly catch-per-unit 

effort estimates among beach seine regions demonstrated that fish densities for most assemblage 

groups were relatively high during the 2014 field season and decreased slightly in 2015.

Proportional unmarked origin of Chinook Salmon. We estimated the origin of unmarked juvenile 

Chinook Salmon using the known ratio of unmarked to marked individuals in hatchery release 

groups, and observed that nearly all juvenile salmon runs captured using beach seines since the 

2000 field season were of natural origin. Conversely, most of the hatchery origin fish were 

captured using trawls. This suggests that hatchery juvenile Chinook Salmon may be less likely to 

occur in unobstructed near shore habitats within the San Francisco Estuary than natural origin 

juvenile Chinook Salmon.
iii

Sacramento Catch Index. The DJFMP calculated a Sacramento Catch Index (SCI) using the 

relative abundance indices of unmarked winter-run sized or older juvenile Chinook Salmon near 

Sacramento. The SCI did not trigger any modified DCC operations in the 2014 field season. 

However, the Sacramento Trawl SCI or the Sacramento Beach Seine SCI exceeded the threshold 

of the salmon decision process on 10 sampling dates during the 2015 field season. This, in 

conjunction with other criteria, either triggered or maintained the closure of the DCC gates on 8

occasions.

Liberty Island Seine. The DJFMP conducted beach seining at Liberty Island from March 2010 

through February 2012 under the BREACH III agreement with the California Department of 

Fish and Wildlife. Sampling has continued from February to June in 2013 to 2015. The 

BREACH III study was intended to provide information regarding how abiotic and biotic factors 

control vegetation colonization and expansion and subsequent responses by higher trophic levels. 

In addition, DJFMP sampling at Liberty Island provides baseline data that can serve as a 

reference site for future restoration efforts at Liberty Island and other north Delta sites in 

conjunction with the EcoRestore (previously Bay Delta Conservation Plan) and the Fish and 

Wildlife Service Operational Criteria and Plan Biological Opinion, respectively. Results from the 

2014 and 2015 field seasons showed trends consistent with the inter-annual variation observed 

collectively from the six seine regions, with juvenile Chinook exhibiting over an order of 

magnitude higher mean catch per unit effort (CPUE) from the 2014 field season to 2015. 

Seasonally, most of this difference occurred during the months of February and March, which is 

also consistent with results from other seine region sites across the North Delta.

The suggested citation for this report is:

Miller, T.W., D. Barnard, J. Speegle, J. Adams, C. Johnston, J.L. Day and L. Smith. 2017. 

Annual report: juvenile fish monitoring during the 2014 and 2015 field seasons within the San 

Francisco Estuary, California. Lodi Fish and Wildlife Office, United States Fish and Wildlife 

Service, Lodi, California. 145p.
iv

TABLE OF CONTENTS

Executive Summary......................................................................................................................................ii

Acknowledgements.......................................................................................................................................v

Acronyms.....................................................................................................................................................vi

Long-Term Monitoring.................................................................................................................................1

Introduction...............................................................................................................................................1

Methods ....................................................................................................................................................2

Monitoring Locations............................................................................................................................2

Trawl Methodology ..............................................................................................................................5

Beach Seine Methodology ..................................................................................................................10

Fish Processing ...................................................................................................................................12

Water Quality......................................................................................................................................13

Fish Assemblage .................................................................................................................................14

Estimate of Hatchery and Natural Origin Juvenile Chinook Salmon .................................................14

Relative Abundance Calculations.......................................................................................................17

Length Frequency ...............................................................................................................................20

River Flow Conditions........................................................................................................................21

Results and Discussion ...........................................................................................................................21

Water Quality......................................................................................................................................22

Fish Assemblage .................................................................................................................................32

Juvenile Chinook Salmon ...................................................................................................................39

Monitoring for Delta Cross Channel Operations........................................................................................65

Introduction.............................................................................................................................................65

Methods ..................................................................................................................................................66

Results and Discussion ...........................................................................................................................69

Liberty Island Beach Seine .........................................................................................................................72

Introduction.............................................................................................................................................72

Methods ..................................................................................................................................................72

Results and Discussion ...........................................................................................................................74

Water Quality......................................................................................................................................74

Fish Assemblage .................................................................................................................................79

Juvenile Chinook Salmon ...................................................................................................................81

References...................................................................................................................................................82

Appendix A.................................................................................................................................................86

Appendix B...............................................................................................................................................134
v

ACKNOWLEDGEMENTS

All fish sampling presented in this report was conducted for the Interagency Ecological Program 

(IEP) for the San Francisco Estuary and funded by the California Department of Water 

Resources and the U.S. Bureau of Reclamation. Members of the IEP include three state agencies 

(the California Department of Water Resources, California Department of Fish and Wildlife, and 

State Water Resources Control Board) and six federal agencies (the U.S. Bureau of Reclamation, 

U.S. Geological Survey, U.S. Fish and Wildlife Service, National Marine Fisheries Service, U.S. 

Army Corps of Engineers, and the U.S. Environmental Protection Agency).

We also acknowledge and extend gratitude to the many biological science field technicians, boat 

operators, interns , and volunteers who spent countless hours under all weather conditions to 

collect these data. We would like to especially thank Brett Anderson, Judith Barkstedt, Erica 

Campos, Emily Celery-Butlin, Philip Choy, Jeffrey Cullen, Dustin Dinh, David Dominguez, 

Kate Erly, Kyle Fronte, Michael Gala, Ashleigh Glover, Andrew Goodman, Christopher Hart, 

Jack Ingram, Carlie Jackson, Katherine Jardine, David LaPlante, Jerrica Lewis, Sean Luis, Sheng 

Ly, Mike Marshall, Jerad Mauldin, Angie Mungia, Paul Miklos, Colleen Moore, Trishelle 

Tempel (Morris), Greg Nelson, Mollie Ogaz, Jacob Osborne, Tony Parra, Oliver Patton, Sintia 

Shahbaz, Pam Tarelli, Denny To, Phil Voong, Spencer Wernett and William (Alex) Woolen for 

biological sampling; Jackie Hagen, Curtis Hagen, Ron Hagins, Patrick Hapgood, Bill Powell, 

and Rick Williams for boat operation; and Angelina Bourandas for helping oversee data entry 

and quality control during the 2014 and 2015 field seasons. We would also like to thank Patricia 

Brandes, Matthew Dekar, Joseph Kirsch, Lori Smith, and Kim Webb for improvements to earlier 

drafts of this report.

Disclaimer: The mention of trade names or commercial products in this report does not constitute 

endorsement or recommendation for use by the federal government.
vi

ACRONYMS

The following acronyms have been used in this report:

CI—Confidence interval

CDFW—California Department of Fish and Wildlife

CDWR—California Department of Water Resources

CPUE—Catch-per-unit effort

CVP—Central Valley Project

CWT—Coded wire tag

DAT—Data Assessment Team

DCC—Delta Cross Channel

DJFMP—Delta Juvenile Fish Monitoring Program

DOSS—Delta Operations for Salmon and Sturgeon working group

ESA—Endangered Species Act

FL—Fork length

IEP—Interagency Ecological Program

KDTR—Kodiak trawl

KLCI—Knights Landing Catch Index

LDC—Length-at-capture-date criteria

LFWO—Lodi Fish and Wildlife Office

MWTR—Mid-water trawl

NMFS—National Marine Fisheries Service

PSMFC—Pacific States Marine Fisheries Commission

RM—River mile

RMIS—Regional Mark Information System

SCI—Sacramento Catch Index

SD—Standard deviation

SE—Standard error

SJRGA—San Joaquin River Group Authority

SWP—State Water Project

SWRCB—State Water Resources Control Board

USBR—United States Bureau of Reclamation

USFWS—United States Fish and Wildlife Service

USGS—United States Geological Survey

WOMT—Water Operations Management Team
1

LONG-TERM MONITORING

Introduction

The San Francisco Estuary (Estuary) is notably the largest estuary in California and provides 

spawning habitat, nursery habitat, and migratory pathways for over 40 freshwater, estuarine, 

euryhaline, marine, and anadromous fish species (Moyle 2002). Historically, the Estuary was 

maintained by natural runoff from an estimated 40% of California's surface area (Nichols et al. 

1986). However, increases in agriculture and urbanization throughout California over the last 

century, coupled with California's Mediterranean climate (i.e., wet winters and dry summers), 

have necessitated intense water management within the Estuary and its watershed. The damming 

of most rivers, confinement of channels, and water diversions and exports has subjected the 

Estuary to artificial flow regimes that can have profound impacts on aquatic habitats and 

organisms (Stevens and Miller 1983; Nichols et al. 1986; Brandes and McLain 2001; Bunn and 

Arthington 2002; Kimmerer 2002; Feyrer and Healey 2003). As a result, fish species of 

management concern within the Estuary have been monitored and studied, in part, by the Delta 

Juvenile Fish Monitoring Program (DJFMP) of the Lodi Fish and Wildlife Office (LFWO, 

formerly Stockton Fish and Wildlife Office) to assess and minimize the effects of water 

operations on fish populations.

The DJFMP, as part of the Interagency Ecological Program, has been monitoring populations of 

juvenile Chinook Salmon Oncorhynchus tshawytscha (hereafter Chinook) within the 

Sacramento-San Joaquin Delta (Delta) and its watershed since 1976 (Dekar et al. 2013). The 

DJFMP and its goals have evolved based on water management needs and endangered species 

listings. Prior to 1992, the DJFMP conducted annual monitoring between April and June to 

assess the effects of water operations on the inter- and intra-annual abundance and distribution of 

primarily juvenile fall-run Chinook within the Delta and lower Sacramento River. Following the 

listing of Sacramento River winter-run Chinook as endangered by the State of California in 1989 

(CDFW 2005) and by the National Marine Fisheries Service in 1994 (59 FR 440), the DJFMP 

expanded the long-term sampling program to one that operated between October and June to

collect more information on all races of juvenile Chinook in the Estuary. The DJFMP was further 

expanded in 1995 to sample year-round, in part, to expand the temporal and geographic 

monitoring of resident fish and Central Valley Steelhead Oncorhynchus mykiss (Dekar et al. 

2013). Today, year-round monitoring continues with an emphasis on populations of all races of 

Chinook in the Delta per the monitoring and reporting terms of the Biological Opinion and 

Conference Opinion on the Long-Term Operations of the Central Valley Project (CVP) and State 

Water Project (SWP, NMFS 2009a).

In general, the fish data collected by the DJFMP are intended to provide basic biological and 

demographic information that can be used to assess trends over time. The first section of this 

report will focus on the DJFMP’s long-term observations of juvenile Chinook and fish 

assemblage structure. The objectives of the annual report for the 2014 (August 1, 2013 to July 

31, 2014) and 2015 (August 1, 2014 to July 31, 2015) field seasons were to (1) report water 

quality information collected concurrently while monitoring fish during the 2014 and 2015 field 

seasons, (2) document the fish assemblage structure at monitoring sites, (3) determine the 
2

abundance and distribution of naturally and hatchery produced juvenile Chinook migrating into 

and out of the Delta, and (4) document the length frequency distributions of unmarked juvenile 

Chinook. Although the water quality data are intended to document the spatial and temporal 

variation of potential fish habitat characteristics within the Estuary and lower rivers, rigorous 

fish-habitat analyses are beyond the scope of this report.

Methods

Monitoring Locations

The San Francisco Estuary consists of three distinct segments: the Sacramento-San Joaquin 

Delta, Suisun Bay, and San Francisco Bay (Moyle 2002). During the 2014 and 2015 field 

seasons, the DJFMP sampled fishes at 3 trawl sites and 56 beach seine sites located within the 

lower Sacramento and San Joaquin Rivers, at and between the entry and exit points of the Delta, 

Liberty Island, and within the San Francisco Bay (Figure 1; Table A.1). 

We used surface trawls to examine the relative abundance of fishes migrating into and out of the 

Delta. Trawl sites were located at the entry (Sacramento and Mossdale trawl sites) and exit 

(Chipps Island Trawl Site) points of the Delta (Figure 1Figure 1; Table A.1). In general, the 

DJFMP sampled each trawl site three days per week, with ten tows per day throughout the 2014 

and 2015 field seasons. Trawl sites were generally sampled Monday, Wednesday, and Friday 

each week throughout the field season to maximize temporal coverage. The California 

Department of Fish and Wildlife (CDFW) has traditionally sampled the Mossdale Trawl Site, 

following similar methodologies, in place of the DJFMP between April and June (SJRGA 2009). 

Data collected from both the DJFMP and CDFW at the Mossdale Trawl Site are included in this 

report.

We used beach seines to quantify the spatial distribution of fishes occurring in unobstructed 

shallow near-shore habitats (e.g., beaches and boat ramps ≤ 1.2 m in depth) throughout the lower 

Sacramento and San Joaquin Rivers, Liberty Island, and the Estuary. Beach seine sites were 

stratified into six geographic seine regions: (1) Lower Sacramento River, (2) North Delta, (3) 

Central Delta, (4) South Delta, (5) Lower San Joaquin River, and (6) San Francisco and San 

Pablo Bay (Figure 1; Table A.1). Seine regions were delineated by proximity to canals or water 

bypasses where fish may be diverted from historical migration routes.

In this dynamic system, occasional changes in river flow or environmental conditions prevent 

sampling or make it necessary to temporarily relocate seine sites (e.g., tidal conditions, or 

submerged or floating aquatic vegetation blocking access to sites). If new seine sites were 

needed, we attempted to relocate the site to another location with similar habitat (e.g., 

hydrogeomorphic characteristics) that was less than 100 m from the original site.

Accessibility of beach seine sites in the San Joaquin River Seine Region varied in difficulty 

between flow conditions. During the 2000–2015 field seasons, when the discharge of the lower 

San Joaquin River dropped below 51 m3/s boat access to specific beach seine locations became 

difficult, so only sites that were accessible from land were sampled (Table A.1). To 
3

accommodate for the inaccessible sites we sampled alternative sites, some of which were over 

100 m from the original sampling locations. We discontinued the use of alternative sites in the 

San Joaquin River Seine Region in the 2014-2015 field seasons in order to decrease biases in fish 

abundance and distribution patterns caused by changing sites during variable flow conditions; 

and only the sites that were sampled when the river was above 51 m3/s during the 2000–2013

field seasons were sampled throughout the entire 2014 and 2015 field seasons. More information 

on monitoring site modifications can be found in the LFWO Metadata file at 

https://www.fws.gov/lodi/juvenile_fish_monitoring_program/jfmp_index.htm.

In general, we sampled fishes at the beach seine sites one day per week, one time per day 

throughout the 2014 and 2015 field seasons within all seine regions except the Lower San 

Joaquin River and the San Francisco and San Pablo Bay seine regions. The beach seine sites that 

were located within the Lower San Joaquin River Seine Region were generally sampled one day 

per week, one time per day from January 1 to July 31 and one day every two weeks from August 

1 to December 31. The beach seine sites that were located within the San Francisco and San 

Pablo Bay Seine Region were generally sampled one day every two weeks, one time per day 

throughout the 2014 and 2015 field seasons based on the low occurrence of fish species of 

management concern.
4

Figure 1. Sites sampled during the 2014 and 2015 field season within the lower Sacramento and 

San Joaquin Rivers and San Francisco Estuary.
5

Trawl Methodology

We sampled at trawl sites using Kodiak (KDTR) and mid-water (MWTR) trawls. The DJFMP 

exclusively uses a MWTR at the Chipps Island Trawl Site and a KDTR at the Mossdale Trawl 

Site. The DJFMP exclusively used a MWTR at the Sacramento Trawl Site prior to 1994, and has 

used a KDTR from October to March and a MWTR for the remainder of each field season 

thereafter (Dekar et al. 2013). The KDTR has been used in place of the MWTR at the 

Sacramento Trawl Site from October to March to maximize the capture of larger Chinook and to 

provide more robust juvenile winter-run Chinook catch indices (Dekar et al. 2013). 

During each sampling day, we attempted ten 20-minute tows between approximately 7am and 

1pm at all trawl sites. All tows were conducted mid-channel and facing upstream at the 

Sacramento and Mossdale trawl sites, which constitute a reach length of approximately 6.5 km 

and 3 km, respectively. In contrast, tows were generally conducted facing both upstream and 

downstream in the north, south, and middle portions of the channel at the Chipps Island Trawl 

Site based on tidal influence on net water velocities. The Chipps Island Trawl Site constitutes a 

reach length of approximately 4 km. The MWTR and KDTR nets were towed by one and two 

boats, respectively, in the top few meters of the water column at a speed necessary and distance 

apart (for KDTR) to ensure that the net mouth remained fully extended and submerged. The 

measure of the distance traveled during each tow was recorded using a calibrated mechanical 

flow meter (General Oceanics, Model #2030) deployed alongside the boat. In general, the 

Sacramento MWTR net was towed at speeds between 0.7–1.0 meters per second (m/s), the 

Chipps Island MWTR net was towed at speeds between 0.9–1.12 m/s, and the KDTR nets were 

towed at speeds between 0.45–0.67 m/s at both the Mossdale and Sacramento trawl sites. 

The Sacramento MWTR net was composed of six panels, each decreasing in mesh size towards 

the cod end (Figure 2). The mesh size for each panel ranged from 20.3 cm stretch at the mouth to 

0.6 cm stretch just before the cod end. The cod end was composed of 0.3 cm weave mesh. The 

fully extended mouth size was 4.15 by 5 m. Two depressors and hydrofoils enabled the net to 

remain at the top few meters of the water column while sampling. Depressors were made of 0.7 

cm thick stainless steel (one on each side of the net lead line) and were attached to the net with 

shackles to extend the bottom line of the mouth. Hydrofoils were made of 0.7 cm thick 

aluminum plates with split floats (one on each side of the net float line) and were attached to the 

net with shackles to extend the top of the net at the water surface. On each side of the net, the 

depressor and hydrofoil were connected to the boat using a 30.5 m Amsteel rope bridle (0.64 cm 

diameter). The net was fished approximately 30 m behind the boat. 

The MWTR net used at the Chipps Island Trawl Site was larger and similar in construction to the 

MWTR net used at the Sacramento Trawl Site (Figure 3). There were five panels, each with 

decreasing mesh size towards the cod end. The mesh size for each panel ranged from 10.2 cm 

stretch at the mouth to 2.5 cm stretch just before the cod end. The cod end was composed of 0.8 

cm knotless material. The fully extended mouth size of the Chipps Island MWTR net was 7.64 

by 9.65 m. The depressors and hydrofoils of the Chipps Island MWTR were larger and were 

connected to the boat identically to those on the Sacramento MWTR. On each side of the net, the 

depressor and hydrofoil were connected to the boat using a 30.5 m Amsteel rope bridle (0.6 cm 
6

diameter) attached to a 15.2 m tow rope (0.95 cm diameter). As a result, the Chipps Island 

MWTR net was fished approximately 45 m behind the boat. 

The KDTR nets used at the Mossdale and Sacramento trawl sites were composed of five panels, 

each decreasing in mesh size towards a live box at the cod end (Figure 4A). The mesh size for 

each panel ranged from 5.1 cm stretch at the mouth to 0.6 cm stretch just before the live box. The 

live box (36 cm wide by 36 cm tall by 49 cm long) was composed of 0.18 cm thick aluminum 

that was perforated with 0.46 cm diameter holes. The live box contained several internal baffles 

to minimize fish mortality and stress due to flow pressure. The fully extended mouth size of the 

KDTR nets were 1.96 by 7.62 m. A float line and lead line enabled the nets to remain at the top 

few meters of the water column while sampling. Additionally, at the front of each wing of the net 

was a 1.83 m metal bar with floats at the top and weights at the bottom to keep depth constant 

while sampling. The KDTR nets were towed behind two boats sitting approximately 4.5 m apart 

(Figure 4B). The KDTR nets were connected to the boats using a 2.3 m rope bridle (2.4 cm 

diameter) attached to a 30.5 m tow rope (0.95 cm diameter), which was attached to the metal bar 

on each side of the net. The net was fished approximately 31 m behind the boats. 

At the end of each MWTR tow, the net was retrieved by the towing vessel using winches to 

collect all the fishes observed in the cod ends. At the end of each KDTR tow, the two towing 

vessels (i.e., net and chase boats) would maneuver alongside each other, and the chase boat 

would transfer its tow rope to the net boat. Subsequently, the crew on the chase boat would travel 

downstream to the live box connected to the KDTR, retrieve, secure, and pull the live box from 

the water into the boat (Figure 5). All fishes collected from the cod end or live box were placed 

in a holding container filled with river water for processing. Lastly, the crew would determine 

the condition of each tow as either “normal” (defined as no twists, snags, or tears in the net, little 

to no [<5%] debris in/on the net, and no [<5%] blockage between the mouth of the net to the live 

box), “fair” (defined as partial twists, snags, or small tears in the net, some [5–25% coverage] 

debris in/on the net, or partial [5–25%] blockage between the mouth of the net to the live box), or 

“poor” (defined as complete twists, snags, or large tears in the net, heavy [>25% coverage] 

debris in/on the net, or near complete [>25%] blockage between the mouth of the net to the live 

box).
7

Figure 2. Schematic drawing of the (A) mid-water trawl net and (B) hydrofoils and depressors 

used at the Sacramento Trawl Site during the 2014 and 2015 field seasons.

Depressor

20.3 cm stretch 

mesh

10.2 cm 

stretch mesh

7.6 cm 

stretch mesh

5.1 cm 

stretch mesh

2.5 cm 

stretch mesh

1 cm stretch 

mesh

0.3 cm weave 

mesh cod end

Mouth opening

4.15 x 5 m 

Hydrofoil

Hydrofoil

Depressor

15.2 cm

30.5 cm

53.3 cm

Split 20.3 x 15.2 cm 

float secured with

stainless bolts

15.2 cm

Hydrofoil—top view Hydrofoil—side view

Float

Depressor—top view Depressor—side view

30.5 cm

45.7 cm

19.1 cm

5.1 cm

Curved

steel

foot

1.3 cm holes

Float

19.1 cm

30.5 m 

bridle ropes

(A)

(B)
8

Figure 3. Schematic drawing of the (A) mid-water trawl net and (B) hydrofoils and depressors 

used at the Chipps Island Trawl Site during the 2014 and 2015 field seasons.

22.9 cm

10.2 cm 

stretch mesh

7.6 cm 

stretch mesh

5.1 cm 

stretch mesh

2.5 cm 

stretch mesh

0.8 cm 

weave mesh 

cod end

3.8 cm 

stretch mesh

Mouth opening

7.64 x 9.65 m

Depressor

Hydrofoil

Hydrofoil

Depressor

40.6 cm

61.0 cm

Split 38.1 x 15.2 cm 

float secured with 

stainless bolts

22.9 cm

Hydrofoil—top view Hydrofoil—side view

Float

Depressor—top view Depressor—side view

45.7 cm

61.0 cm

22.9 cm

6.4 cm

Curved

steel

foot

1.3 cm holes

Float

22.9 cm

(A)

(B)

30.5 m 

bridle ropes
9

Figure 4. Schematic drawing of the (A) Kodiak trawl net used and (B) position of the boats 

during Kodiak trawling at the Sacramento and Mossdale trawl sites during the 2014 and 2015 

field seasons.

Figure 5. The Kodiak trawl (A) live box (B) being retrieved, (C) secured, and (D) 

pulled into the vessel.

5.1 cm

stretch mesh

3.8 cm 

stretch mesh

2.5 cm

stretch mesh

1.3 cm

stretch mesh

0.6 cm

stretch mesh

Live box 

Mouth opening

1.96 x 7.62 m

1.83 m metal bar

Float line

Lead line

Float 

2.3 m bridle 

ropes

30.5 m 

tow rope

(A)

(B) Top of metal bars

Tow rope Net

4.5 m
10

Beach Seine Methodology

Sampling at beach seine sites was conducted approximately between 7am and 1pm. We sampled 

using a 15.2 by 1.3 m beach seine net with 3 mm delta square mesh, a 1.2 m bag in the center of 

the net, and a float line and lead line attached to 1.8 m tall wooden poles on each side. In general, 

beach seines were deployed along the shoreline by two crew members within unobstructed 

habitats including boat ramps, mud banks, and sandy beaches. 

Rollers were added to the lead line of the beach seine to prevent the net from sinking into fine 

substrates, which would otherwise impede the completion of the seine haul. Based on comments 

within the beach seine database, this occurred at a total of 11 seine sampling events between 

August and September of the 2014 field season. 

The beach seines were generally deployed by two crewmembers starting from the downstream 

portion of each site to limit disturbance (e.g., displacement of sediment into the site). Crew 

member 1 pulled the seine into the water, perpendicular from the shoreline, as crew member 2 

secured the opposite end of the seine to the shoreline (Figure 6A). After reaching a depth of up to 

1.2 m, a distance of up to 15 m, or an obstacle; crew member 1 stopped and measured the 

distance (i.e., length) to the shoreline and depth to the nearest 1 m and 0.1 m, respectively 

(Figure 7). Obstacles were defined as any structure that could compromise safety or gear 

efficiency; e.g., steep banks or holes, fast water current, submerged aquatic vegetation, or large 

woody debris. If the depths of the seine varied between measurements, the seine depth was 

obtained by averaging the two depth measurements. Next, crew member 2 carried their end of 

the seine to crew member 1 and placed it in the same location as crew member 1. The seine was 

then distributed from that point upstream and as parallel to the shoreline as possible by crew 

member 1 (Figure 6B). Lastly, crew members 1 and 2 pulled the ends of the seine simultaneously 

toward and perpendicular to the shoreline while attempting to maintain the starting width (Figure 

6C). The net was continuously pulled towards the shoreline until the lead line of the seine bag 

was on shore (Figure 6D). After the seine haul was completed, all fish were collected from the 

bag and other parts of the seine and placed in a holding container filled with river water for 

processing. The crew would then determine the condition of the sample as either “normal” 

(defined as no twists, snags, or tears in the net, and the seine was pulled steadily while keeping 

the lead line in contact with the substrate and float line at or above the water’s surface), “fair” 

(defined as partial twists, snags, or small tears in the net, but the seine was pulled steadily while 

keeping the lead line in contact with the substrate and float line at or above the water surface), or 

“poor” (defined as complete twists, snags, or large tears in the net, or the seine was not pulled 

steadily, or the lead line was not in contact with the substrate, or float line was below the water 

surface).
11

Figure 6. Photographs of the Delta Juvenile Fish Monitoring Program (DJFMP) conducting a 

beach seine at station SR024E on the bank of the Sacramento River: seine (A) deployed 

downstream of site, (B) distributed upstream parallel to the shoreline (C) pulled in toward the 

shoreline, and (D) position at the end of a haul.

Figure 7. Schematic diagram of beach seine measurements: (A) three-dimensional view and (B)

overhead view.

Length

Width

Shore

Depth 1 Depth 2

(B)

Width

Shore

Depth 1

Depth 2

Length

(A)

(C) (D)

(A) (B)
12

Fish Processing

We identified all fish in each sample that were ≥ 25 mm fork length (FL) to species or race, with 

the exception of five species that were readily identified at ≥ 20 mm FL: Sacramento Splittail 

Pogonichthys macrolepidotus, Three-spine Stickleback Gasterosteus aculeatus, Western 

Mosquito Fish Gambusia affinis, Rainwater Killifish Lucania parva, and Sacramento Sucker 

Catostomus occidentalis. Prior to release at the site of capture, we measured fish to the nearest 1 

mm FL. If greater than 50 individuals of a Chinook race, as designated by the river length-atcapture-date criteria (LDC, see paragraph below), or other species listed under the Endangered 

Species Act (ESA) were captured, a subsample of 50 individuals was randomly measured for FL 

and the rest were counted and not measured (referred to as a “plus count”). If greater than 30 

individuals of a non-listed species were captured, a subsample of 30 individuals was randomly 

measured for FL and the rest were counted and not measured. Fish that could not be accurately 

identified in the field were preserved and brought back to the laboratory. The identification of 

preserved fishes was then confirmed with the use of dichotomous keys or with the aid of a 

microscope.

Only juvenile Chinook with missing (clipped) adipose fins were considered marked fish. In 

general, fish possessing other forms of marks or tags (e.g., stain dye, disc tags, acoustic tags) 

were not included within this report to further minimize the influence of recaptures and/or 

unnatural occupancy induced by other fishery investigations. Stain dye marked juvenile Chinook 

released near the Mossdale Trawl Site were only used to estimate trawl efficiency (see “Absolute 

Abundance Calculation” section). All clipped juvenile Chinook observed during the 2014 and 

2015 field seasons were considered hatchery-reared and were brought back to the lab to process 

the coded wire tag (CWT). 

Recovered CWTs can provide important biological information to natural resource managers 

(e.g., an individual's race, hatchery of origin, and the date and location released). Therefore, all 

clipped Chinook were euthanized in the field and brought back to the laboratory. We then 

removed, read, and recorded the tag code of all CWTs recovered. We obtained corresponding tag 

information (e.g., race and release location) from the Regional Mark Information System (RMIS) 

maintained by the Pacific States Marine Fisheries Commission (PSMFC 2017). Details regarding 

CWT recoveries during the 2014 and 2015 field seasons can be found in “Appendix A” section. 

The race of all unmarked juvenile Chinook was determined using the river LDC developed by 

Fisher (1992) and modified by Greene (1992). The assumptions associated with the river LDC 

for the Sacramento-San Joaquin River basin include that (1) spawning of fall-run Chinook occurs 

between October 1–December 31, (2) spawning of late fall-run Chinook occurs between January 

1–April 15, (3) spawning of winter-run Chinook occurs between April 16–August 15, (4) 

spawning of spring-run Chinook occurs between August 16–September 30, and (5) growth rate 

of juveniles is identical among all races of Chinook (Fisher 1992). Although one or more of 

these assumptions are likely violated (Fisher 1994; Yoshiyama et al. 1998), the river LDC is 

currently widely used by managers, and is the only cost effective and logistically feasible way to 

differentiate between the different races of juvenile Chinook in the field. Fisher (1994) noted that 

Chinook races within the Central Valley do appear to spawn at distinctly separate time periods 

except for fall- and spring-run due to the loss of headwater habitats (e.g., resulting from dams), 
13

forced coexistence, and subsequent hybridization within the Sacramento River basin (Cope and 

Slater 1957; Slater 1963). As a result, many of the Chinook characterized as spring-run by the 

river LDC may actually be fall-run. Additionally, some genetic analyses of DNA genotypes have 

demonstrated the inaccuracy of the river LDC that has been used to determine Chinook races 

within the San Francisco Estuary, especially between fall- and spring-run salmon (e.g., Banks et 

al. 2000; Greig et al. 2003; Banks et al. 2014). Although the LDC does an adequate job of 

identifying winter run, many of the fish falling within the winter run size using the LDC, are 

actually from another run (Pyper et al, 2013). We used the river LDC to differentiate between 

unmarked winter-run sized and a combined group of fall-, late fall-, and spring-run sized juvenile 

Chinook. The race designations used in this report should be considered a rough approximation 

and not interpreted as definitive. See the following section called “Estimate of Hatchery and 

Natural Origin Juvenile Chinook Salmon” for information on how unmarked hatchery versus 

natural origin Chinook are determined. 

All juvenile Chinook collected at the Mossdale Trawl Site and within the Lower San Joaquin 

River Seine Region were classified as fall-run regardless of their length at the date of capture, 

and thus included in the fall-, late fall-, and spring-run group, because fall-run Chinook are 

reportedly the only race to still occur within the San Joaquin River and its main tributaries 

(Yoshiyama et al. 1998). Although the South and Central Delta seine regions are located within 

the San Joaquin River basin, there is potential for late fall-, winter-, and spring-run juveniles of 

Sacramento River origin to migrate into the interior delta through Georgiana Slough, the Delta 

Cross Channel (DCC), Three-Mile Slough and in the lower San Joaquin River. Therefore, the 

river LDC was still used to determine the race of juvenile Chinook within the South and Central 

Delta seine regions. 

Water Quality

We measured water temperature, dissolved oxygen, turbidity, and conductivity immediately 

before each trawl and during or after each seine haul during the 2014 and 2015 field seasons. We 

have consistently measured water temperature at all monitoring sites during or immediately 

before each sampling occasion since the late 1970s. Additionally, we have consistently measured 

dissolved oxygen, turbidity, and conductivity at all monitoring locations since January of 2012. 

We used a YSI 85 or YSI PRO 2030 meter to measure water temperature to the nearest 0.1 ̊C, 

dissolved oxygen to the nearest 0.01 mg/L, and conductivity to the nearest 0.01 

microsiemen/centimeter (μS/cm) for freshwater or millisiemen/centimeter (mS/cm) for salt 

water. Turbidity was measured using a HACH 2100Q turbidity meter to the nearest 0.01 

nephelometric turbidity unit (NTU). All measurements or samples were collected 20–30 cm 

below the surface of the water.

We presented the raw temperature, dissolved oxygen, turbidity, and conductivity estimates by 

month for each trawl site and beach seine region during the 2014 and 2015 field seasons as box 

plots (median and percentiles) to demonstrate the spatial and temporal variability of the water 

quality conditions representative of our monitoring sites during sampling.
14

Fish Assemblage

We classified fish species into seven distinct assemblage groups based on shared origin, habitat 

requirements, and life history strategies (Moyle 2002): (1) anadromous-benthic-native, (2) 

anadromous-pelagic-native, (3) anadromous-pelagic-nonnative, (4) benthic-native, (5) benthicnonnative, (6) pelagic-native, and (7) pelagic-nonnative (Table A.2). All juvenile unmarked 

Chinook captured were considered members of the anadromous-pelagic-native group. No 

marked Chinook or marked steelhead were included in any of the assemblage groups, though 

unmarked hatchery Chinook and unmarked Steelhead were included (see next subsection, 

Estimate of Hatchery and Natural Origin Juvenile Chinook Salmon).

Estimate of Hatchery and Natural Origin Juvenile Chinook Salmon

In general, hatcheries have used CWTs, indicated by clipped adipose fins, to mark all hatchery 

produced late fall-, winter-, and spring-run juvenile Chinook in the Central Valley (Kevin 

Niemela, USFWS, personal communication; Williams 2006). However, a small proportion of 

late fall-, winter-, and spring-run Chinook fin clips are missed during tagging at the hatchery, and 

recorded in RMIS as unmarked (Kevin Niemela, USFWS, personal communication; PSMFC 

2017). Conversely, the marking and CWT tagging rates of hatchery reared juvenile fall-run 

Chinook have varied considerably (5–95%; Johnson 2004). Starting in 2007, Central Valley 

hatcheries began implementing the constant fractional marking of hatchery produced juvenile 

fall-run Chinook, where at least 25% of individuals within each hatchery release group are 

marked and have a CWT inserted (Nandor et al. 2010). Because unmarked hatchery reared 

juvenile Chinook are still being released into the Central Valley, there is considerable uncertainty 

concerning the origin (i.e., naturally or hatchery produced) of unmarked juvenile Chinook 

observed during DJFMP monitoring. This uncertainty impacts the program’s ability to inform 

research or management decisions concerning natural origin juvenile Chinook (Williams 2006; 

Dekar et al. 2013). 

Therefore, we developed an equation to estimate the origin of juvenile Chinook observed during 

the 2000 to 2015 field seasons. We applied the equation to all races of juvenile Chinook to 

account for any possible unmarked proportion of a hatchery release group, either caused by 

intentional unmarking (fall-run), or fin clip failure during tagging (late fall-, winter-, and springrun).We estimated the number of unmarked hatchery origin juvenile Chinook (Hs) for each 

sample (e.g., trawl tow or seine haul) and race group as: 

Hs = ∑(Cg x Pg)

( 1 )

where s indexes an individual sample (i.e., a beach seine haul or trawl tow), g indexes a CWT 

release group, Cg represents the total number of marked individuals collected from the CWT 

release group, and Pg represents the proportion of unmarked to marked individuals within the 

CWT release group. Pg was obtained from state and federal hatchery records (PSMFC 2017). 

The primary assumption of this approach was that marked and unmarked individuals within a 

CWT release group have identical capture probabilities and availability during sampling. 
15

We included juvenile Chinook that were reported as fall- and spring-run hybrids in hatchery 

records in the combined fall-, late fall-, and spring-run group. We also included all other hybridrun juvenile Chinook without race descriptions in this group based on unlikely hybridization 

between winter-run Chinook and other races (Slater 1963). Additionally, we omitted any CWT 

release groups that were associated with “wild type” origin juvenile Chinook based on these 

groups being experimental and rare. 

We then summed the total number of unmarked hatchery origin juvenile Chinook observed 

within a sample day for each race group and monitoring site (Hd). Subsequently, we estimated 

the number of natural origin juvenile Chinook for each race group and monitoring site within a 

sample day (Wd) as:

Wd = Od − Hd

( 2 )

where Od denotes the total number of unmarked juvenile salmon observed during a sample day 

for a race group and monitoring site. If the estimated number of unmarked hatchery origin 

individuals exceeded the total number of unmarked juvenile Chinook observed for a race group 

during a sample day at a monitoring location (occurred in < 1% of samples), we designated all 

unmarked individuals observed as unmarked hatchery individuals. All clipped juvenile Chinook 

included in the analysis were considered to be of hatchery origin.

Prior to 2000, large groups of unmarked fall-run juvenile Chinook were regularly released by the 

state and federal hatcheries throughout the Delta that were not associated with any marked group 

(Kevin Niemela, USFWS, personal communication; PSMFC 2017). Consequently, our approach 

to estimate the number of natural and hatchery origin juvenile Chinook at our monitoring 

locations could not be applied to our catch data for the fall-, late fall-, and spring-run group prior 

to 2000. As a result, all unmarked fall-, late fall-, and spring-run fish observed prior to the 2000 

field season were considered to have an unknown origin. After 2000, groups containing only 

unmarked individuals were released at Battle Creek, Sacramento River, Feather River, and 

downstream of Chipps Island. We assumed that unmarked releases downstream of Chipps Island 

would not bias our estimation of fish origin because most juvenile Chinook were likely actively 

migrating downstream and observations of CWT individuals released at these locations are 

minimal. 

To minimize the impact of unmarked hatchery releases at other locations, we estimated periods 

of time when individuals from these unmarked hatchery release groups likely occurred within the 

Delta. We considered all unmarked individuals observed while monitoring during these periods 

of time to have unknown origin. We estimated periods of occupancy within the Delta using the 

observed travel times of individual CWT fish released from each of the locations where groups 

containing only unmarked hatchery fish have been released (i.e., Battle Creek, Feather River, 

Sacramento River at Verona, and Sacramento River at Red Bluff Diversion Dam) to the entry 

(Sacramento Trawl Site) and exit (Chipps Island Trawl Site) locations of the Delta (Table 1). To 

incorporate uncertainty, we defined the periods of occupancy using the time (i.e., days) between 

when the first and last 2.5% of marked fish were detected at either Sacramento or Chipps Island

relative to the release date of unmarked hatchery groups (Table 1). CWT fish released in the 

Sacramento River at Verona and the Red Bluff Diversion Dam took longer to reach the Chipps 

Island and Sacramento trawl sites than CWT fish released at Battle Creek or Feather River. The 

longer travel times may have been the result of fewer observations of CWT fish originating from 
16

the Sacramento River at Verona and the Red Bluff Diversion Dam release sites, resulting in 

higher uncertainty in the estimated days of occupancy within the Delta. Alternatively, the 

releases at Verona and the Red Bluff Diversion Dam may have contained higher proportions of 

fry (Pat Brandes, USFWS, personal communication), which move less quickly through the Delta 

than smolts (Kjelson et al. 1982) and may have caused the longer travel times.

Table 1. The estimated period (days) of occupancy of CWT fish between when CWT fish were 

released at locations where unmarked releases occurred and captured at the Chipps Island and 

Sacramento trawl sites during the 2000–2015 field seasons. See Tables A.20 and A.21 for further 

detail on race designations.

Release 

location

Capture 

location 

(trawl site)

N (# of 

CWT fish 

observed)

Days between 

capture of first 

2.5% of fish 

and release date

Days between 

capture of last 

2.5% of fish 

and release date

Estimated 

days of 

occupancy 

within Delta

Battle 

Creek

Chipps 

Island 5936 7 30

25

Sacramento 2832 5 21

Feather 

River

Chipps 

Island 1296 4 33

33

Sacramento 190 2 35

Sacramento 

River at 

Verona

Chipps 

Island 67 24 76

74

Sacramento 107 2 28

Sacramento 

River at 

Red Bluff 

Diversion 

Dam

Chipps 

Island 121 28 75

71

Sacramento 30 4 66
17

Relative Abundance Calculations

We standardized the samples collected within a day for each assemblage and for the origin 

groups of winter-run sized and the fall-, late fall-, and spring-run sized group of juvenile 

Chinook to catch-per-unit effort (CPUE) as fish per unit volume sampled (fish/10,000 m3) using 

the following equations:

Seine CPUEd =

∑(Catchs)

∑(0.5 · Depths

· Widths· Lengths)

· 10,000 ( 3 )

Trawl CPUEd =

∑(Catchs)

∑(Distance traveleds

· Net mouth area)

· 10,000 ( 4 )

where s indexes individual samples (i.e., a beach seine haul or trawl tow), and d indexes sample 

days. Effort was measured by the volume of water sampled by a beach seine, KDTR, or MWTR. 

By assuming a constant slope from the shore to the maximum seine depth, the volume of the 

water sampled using beach seines was calculated by using 0.5 multiplied by the depth. Because 

the MWTR and KDTR nets do not open completely while under tow and net mouth dimensions 

vary within and among tows (USFWS 1993), we used previously quantified estimates of mean 

net mouth area for this report. The mean net mouth area for MWTR nets used for the Chipps 

Island and Sacramento trawl sites were obtained from 3–4 physical measurements taken while 

sampling and were reported as 18.58 m2and 5.08 m2, respectively (USFWS 1993). The mean net 

mouth area for KDTR nets used for the Mossdale and Sacramento trawl sites were obtained by 

extrapolating from the mean net mouth area of the MWTRs and were reported as 12.54 m2

(USFWS 1998). 

We examined the spatial and temporal trends of the relative abundance by averaging and 

comparing CPUE estimates at monthly and yearly scales. The primary assumption associated 

with these CPUE comparisons is that gear efficiency (i.e., detection probabilities) is constant 

over time at each trawl or seine site, and comparable among trawl sites and seine regions. We 

treated Chinook races and origin groups or assemblage groups, seine regions, trawl sites, and 

gear types separately for all mean CPUE calculations. Because the number of samples collected 

varied within and among weeks for sites within seine regions and trawl sites, data were 

summarized using weekly, monthly, and yearly CPUE averages to minimize the overweighting 

of sample days and/or locations. To limit the bias of diel effects or variable gear efficiency on 

CPUE value comparisons, we only averaged samples collected between 07:00 am and 04:00 pm, 

and excluded those of poor condition (i.e., compromised gear deployment) within our 

calculations.

The mean weekly CPUE was calculated for each trawl site and seine region as the sum of the 

daily CPUE for a trawl or seine site during each sample week divided by the number of days 

sampled each sample week. Subsequently, the mean weekly CPUE values were averaged among 

seine sites within regions. A sample week was defined as Sunday to Saturday. However, sample 

weeks including the first or last day of the field season only included days falling within the field 

season. The mean monthly CPUE was calculated as the sum of the mean weekly CPUE for a 

trawl site or seine region during each calendar month divided by the number of sample weeks 
18

sampled each calendar month. If a sample week occurred in more than one calendar month, the 

sample week was assigned to the calendar month that contained the start of the sample week. We 

switch between gear types (KDTR and MWTR) at Sacramento Trawl Site during October and 

April each field season. The last sample week of March of the 2014 field season included the 

first two sampling days with the midwater trawl in April. Therefore, we presented the monthly 

CPUE averages for both KDTR and MWTR samples during March of the 2014 field season. The 

last sample week of September and March of the 2015 field season included the first two 

sampling days of October and April, respectively. Therefore, we presented the monthly CPUE 

averages for both KDTR and MWTR samples during September and March of the 2015 field 

season. This also resulted in the KDTR CPUE for September and the MWTR CPUE for March 

of the 2015 field season at the Sacramento Trawl Site each being generated from only 2 sample 

days, occurring within one week. Similarly, the MWTR CPUE for March of the 2014 field 

season also had only two sample days, occurring within one week. The mean yearly CPUE was 

calculated as the sum of the mean monthly CPUE for a trawl site or seine region during each 

field season divided by the number of months sampled each field season.

We calculated and graphed the mean monthly CPUE of Chinook and assemblage groups to make 

intra-annual comparisons during the 2014 and 2015 field seasons. For inter-annual comparisons 

of CPUE for juvenile Chinook and assemblage groups, we calculated and graphed mean yearly 

CPUE values starting in the 2000 field season for most trawl sites and seine regions. Confidence 

limits were omitted from the CPUE figures since uncertainty could not be accurately quantified 

after the computational series of averages. Thus, values presented are estimates and may 

incorporate a high degree of uncertainty. 

In general, sampling methods have remained consistent from before the 2000 field season to the 

present, including year-round sampling and standardized methods and gears. However, we 

calculated mean yearly CPUE values for the Mossdale Trawl Site only during the 2004 through 

2015 field seasons for juvenile Chinook and assemblage groups because the start of year-round 

sampling did not occur until January 2003. Prior to the 2004 field season, the only months 

consistently sampled at the Mossdale Trawl Site were April through June. We have not reported

April through June data prior to 2004 because these data have been already reported annually by 

the CDFW. We also calculated mean yearly CPUE values during the 1995 through 2013 field 

seasons year-round for both race groups of juvenile Chinook at the Chipps Island Trawl Site, 

based on the site’s historical context for monitoring juvenile salmonids. Prior to the 1995 field 

season, the Chipps Island Trawl Site was only consistently sampled from April through June to 

target juvenile fall-run Chinook smolts. We calculated mean yearly CPUE values using April 

through June at the Chipps Island Trawl Site during the 1978 through 2015 field seasons for 

juvenile fall-, late fall-, and spring-run Chinook to extend our historical coverage. Though the 

relative abundances for the fall-, late fall-, and spring-run race groups are not presented 

individually, the total catch of each race of juvenile Chinook caught in the 2014 and 2015 field 

seasons can be found in Tables A.3 and A.4.

Absolute Abundance Calculation

The absolute abundances of juvenile Chinook of each length at date group of winter-run sized 

salmon and the combined fall-, late fall-, and spring-run sized salmon group immigrating into 
19

and emigrating out of the Delta were estimated on a monthly scale from the 1978 to 2015 field 

seasons using the data collected at the Sacramento, Mossdale, and Chipps Island trawl sites. 

Annual comparisons of the absolute abundance of juvenile Chinook were limited to years and 

months when sampling was relatively consistent. The monthly absolute abundance (N) of (1) 

marked, (2) natural origin, (3) hatchery origin, and (4) unknown origin juvenile Chinook for both 

juvenile winter-run sized, and fall-, late fall-, and spring-run sized group were estimated using 

the methods modified from USFWS (1987) as:

Ni =

ni

ti· TRR ̅̅̅̅̅̅

( 5 )

where i indexes months, ni represents the total number of juveniles collected at the trawl site 

during a month, ti represents the fraction of time the trawl site was sampled during a month, and 

TRR ̅̅̅̅̅̅ represents the mean trawl recovery rate at the trawl site. The assumption of this approach is 

that juvenile salmon are equally distributed in time as they migrate past the trawl sites and are 

never recaptured. It also assumes that the efficiency of the trawls is constant in space (i.e., 

throughout all sampling conditions) and time (i.e., within and among months).

The trawl recovery rate TRR ̅̅̅̅̅̅ for the Chipps Island trawl was estimated using the capture of CWT 

juvenile Chinook released approximately 10 and 12 km upstream of the Chipps Island Trawl Site 

at Sherman Island or Jersey Point. We estimated the TRR for the Sacramento trawl using the 

capture of CWT juvenile Chinook released approximately 4 and 8 km upstream of the 

Sacramento Trawl Site at Miller Park and the Broderick Boat Ramp, respectively. The TRR ̅̅̅̅̅̅ was 

calculated separately for the MWTR and KDTR nets used at the Sacramento Trawl Site to reflect 

possible differences in net efficiency. Lastly, we estimated the TRR for the Mossdale trawl using 

the capture of CWT and dye marked juvenile Chinook released approximately 3 km upstream of 

the Mossdale Trawl Site at Mossdale Crossing. The TRR for each trawl site was calculated as:

TRRk =

nrecovered

navailable

( 6 )

where k indexes release groups at a release site, nrecovered represents the total number of CWT 

juvenile Chinook within a release group collected at the trawl site, and navailable represents the 

number of CWT juvenile Chinook within a release group available for collection at the trawl site. 

Recognizing that the TRR can vary among release groups based on differences in sampling 

effort, navailable was estimated for each release group as:

navailable = nreleased · t ( 7 )

where nreleased represents the total number of CWT juvenile Chinook within a release group and t 

represents the fraction of time the trawl site was sampled from the first recovery to the last 

recovery of CWT juvenile Chinook in the release group. The assumption of this approach is that 

juvenile Chinook within a release group are equally distributed in time and have 100% survival.

A release group was defined as a group of similarly tagged or marked (CWT or spray dyed) 

juvenile Chinook that had the same hatchery origin and were released at the same location and 
20

time. A total of 131 CWT releases have occurred at Sherman Island or Jersey Point between the 

1989 and 2015 field seasons. Forty-seven CWT releases have occurred at Miller Park and 

Broderick Boat Ramp between the 1988 and 2009 field seasons. We calculated the TRR ̅̅̅̅̅̅ for the 

Chipps Island Trawl Site and the Sacramento Trawl Site using the recoveries from all the groups 

released at Sherman Island and Jersey Point, and at Miller Park and Broderick Boat Ramp, 

respectively, to maximize sample size and obtain a more robust estimate. The average fork 

lengths for the release groups near Chipps Island and Sacramento trawl sites ranged from 70–179 

mm and 56–138 mm, respectively, which corresponds to the majority of unmarked juvenile 

Chinook historically collected at these locations. All CWT release group data were obtained 

through the Regional Mark Information System (PSMFC 2017). To maximize sample size, we 

estimated the TRR ̅̅̅̅̅̅ for the Mossdale Trawl Site using the recoveries of all CWT and spray dye 

release groups. Although the stain dye releases often reused marks (i.e., dye colors) within 

seasons, these releases were spaced at least 7 days apart and we determined that approximately 

98% of CWT individuals released at Mossdale Crossing were detected at the Mossdale Trawl 

Site within 7 days from being released. A total of five CWT releases have occurred at Mossdale 

Crossing since the 2003 field season. There were two releases that were listed as Jersey Point, 

however RMIS notes that a proportion of the fish were released at Mossdale due to truck 

malfunction (PSMFC 2017). These fish were not included in the efficiency estimate because of 

the uncertainty associated with their release information. In addition, the CDFW has released 48 

stain dye marked groups of hatchery reared juvenile Chinook at Mossdale Crossing to estimate 

trawl efficiency at the Mossdale Trawl Site since the 1997 field season (SJRGA 2009; Steve 

Tsao, CDFW, personal communication).

The TRR ̅̅̅̅̅̅ was calculated for each trawl site as an average of TRRs weighted by the number of 

individuals within each release group. To incorporate uncertainty in the estimated TRR ̅̅̅̅̅̅, the 

monthly absolute abundance estimates were calculated using the TR̅̅̅̅̅R̅ and its 95% confidence 

interval (CI). The intervals should be considered minimum confidence limits because they only 

incorporate the uncertainty associated with the TRR ̅̅̅̅̅̅ estimates. We calculated absolute 

abundance estimates at the Chipps Island Trawl Site from April through June during the 1978 

through 2015 field seasons for the fall-, late fall-, and spring-run sized juvenile Chinook group. 

We also calculated annual absolute abundance estimates during the 1995–2015, 2000–2015, and 

2004–2015 field seasons at the Chipps Island, Sacramento, and Mossdale trawl sites, 

respectively, for both winter-run sized and the fall-, late fall-, and spring-run sized groups of 

Chinook.

Length Frequency

We plotted length frequency distributions to assess temporal size shifts for all unmarked juvenile 

Chinook Salmon during the 2014 and 2015 field seasons for each seine region and trawl site. In 

cases where Chinook were “plus counted” (i.e., only counted and not measured within a sample) 

the FLs of the unmeasured fish were obtained by extrapolating from the fish that were measured 

within the sample. For example, if 100 individuals were plus counted within a sample and 20% 

of the measured individuals had a FL of 45 mm, we assumed that 20 of the 100 plus counted 

individuals also possessed a FL of 45 mm. Because we categorized the race of unmarked 

juvenile Chinook using the river LDC, we reported the length frequency distribution of all 
21

unmarked juvenile Chinook together for each seine region and trawl site without any race

distinction to avoid bias. 

River Flow Conditions

River flow data were obtained from the USGS and CDWR (USGS 2014; CDWR 2014). We 

obtained mean daily discharge data at the Colusa (River Mile [RM] 144) and Freeport (RM 48) 

gauging stations on the lower Sacramento River, and at the Vernalis (RM 114) gauging station 

on the lower San Joaquin River to represent the primary flow inputs into the Estuary. Further, 

estimates of the daily Delta outflow past Chipps Island towards the San Francisco Bay, which 

takes into account water exports, were obtained from Dayflow (CDWR 2014). We also obtained 

water year type classifications for the Sacramento and San Joaquin River basins from the 

California Data Exchange Center (CDWR 2014b). 

We presented the mean monthly CPUE of Chinook races and fish assemblage groups along with 

mean monthly discharge during the 2014 and 2015 field seasons. Similarly, we compared the 

yearly CPUE of Chinook races and fish assemblage groups along with mean yearly discharge at 

each trawl site and seine region. The CPUE of fishes within the Lower Sacramento River Seine 

Region, North Delta Seine Region, and the Sacramento Trawl Site were compared to discharge 

data measured at Freeport. The CPUE data from the Lower San Joaquin River Seine Region, 

South Delta Seine Region, Central Delta Seine Region, and the Mossdale Trawl Site were 

compared to discharge data measured at Vernalis. Finally, the CPUE of fishes within the Chipps 

Island Trawl Site and San Francisco and San Pablo Bay Seine Region were related to estimated 

Delta outflow. These comparisons were selected to broadly represent what fish experience, in 

terms of average daily flow, at the sampling locations.

Results and Discussion

During the 2014 and 2015 field seasons, 9,038 trawl samples were collected without any 

malfunctions in gear that would preclude effective sampling by the net. We completed 2,801 

trawls at the Chipps Island Trawl Site, 3,239 trawls at the Mossdale Trawl Site, and 2,998 trawls 

at the Sacramento Trawl Site. The trawl tows were evenly distributed throughout the 2014 and 

2015 field seasons (Tables A.5 and A.6). As a result, we considered the inter- and intra-annual 

trawl catch comparisons robust due to minimal spatial and temporal bias. 

During the 2014 and 2015 field seasons, 3,977 seine samples were collected without any gear 

malfunctions that would undermine catch performance by the net. There was considerable spatial 

and temporal variability in the number of samples collected at sites within nearly all seine 

regions during the 2014 and 2015 field seasons (Tables A.7–A.18), similar to the 2010 to 2013 

field seasons (Speegle et al. 2013, Barnard et al. 2015). For example, on average approximately 

60% and 40% of the historically sampled sites within the South Delta Seine Region were 

effectively sampled during sample weeks within the 2014 and 2015 field seasons, respectively 

(Tables A.13 and A.14). The number of samples collected within the South Delta Seine Region 

during the 2014 (n=293) and 2015 (n=205) field seasons were considerably lower than the 

previous decade's annual average (mean= 329, SE=15.7). In addition, on average approximately 

70% and 58% of the historically sampled sites within the Lower San Joaquin Seine Region were 
22

effectively sampled during sample weeks within the 2014 and 2015 field seasons, respectively 

(Tables A.15 and A.16). As a result, catch data associated with these seine regions may contain 

both inter- and intra-annual bias. 

Throughout the 2014 and 2015 field seasons, the inability to effectively sample seine sites 

resulted from the expansion of submerged, emergent, and floating aquatic vegetation, and low 

river discharge (Table A.19). The DJFMP is currently investigating the feasibility of 

implementing a stratified random sampling design for boat electrofishing to supplement beach 

seining within the San Francisco Estuary. New sampling methods are needed to establish nonbiased representative catch data within all near-shore littoral habitats within the lower rivers and 

Delta, not just those at beaches and boat ramps.

Within this report, seine catch data were primarily used to evaluate the general temporal and 

spatial distribution patterns (i.e., occupancy) of fish within the San Francisco Estuary. Although 

the spatial and temporal variability of the samples collected within seine regions can affect 

occupancy patterns (e.g., discerning between false absence and true absence within sites and 

regions; differential detection probability between sites), the DJFMP seine catch data documents 

the presence of fishes at a given time and location (Tables A.5–A.18). However, detection 

probability and the probability of reporting false absences (present but not captured) remain 

unknown.

Water Quality

We collected 52,274 water quality samples during the 2014 and 2015 field seasons: 13,121 water 

temperature, 13,073 conductivity, 13,015 dissolved oxygen, and 13,065 turbidity samples. The 

intra-annual variability in water temperature was consistent among the beach seine regions and 

trawl sites during the 2014 and 2015 field seasons (Figures 8 and 9). Temperature ranged from 

3.6 to 29.6°C among our seine regions and trawl sites during the 2014 field season and 5.7 to 

28.8°C during the 2015 field season. Water temperatures, on average, were highest within the 

lower San Joaquin River, South Delta and Central Delta regions relative to other regions during 

the summer of both field seasons. Further, the summer temperatures were, on average, higher 

during the 2015 field season relative to the 2014 field season within all regions. Temperatures 

often exceeded 25°C during the summer (June through August) of the 2014 and 2015 field 

seasons; critically dry years within both the Sacramento River and San Joaquin River Basins

(Table A.19).

We observed dissolved oxygen values ranging from 2.1 to 20.7 mg/L among our seine regions 

and trawl sites during the 2014 field season and 2.2 to 18.46 mg/L among our seine regions and 

trawl sites during the 2015 field season (Figures 10 and 11). In general, dissolved oxygen was 

slightly higher during the winter season and lower during the summer season for all seine regions 

and trawl sites during both field seasons. Spring of the 2014 field season had a very wide range 

of dissolved oxygen levels, especially in the Lower San Joaquin River and South Delta seine 

regions (Figure 10). The most variation in the 2015 sampling season was in the spring in the San 

Joaquin River seine region as well. During the 2014 field season, we observed the dissolved 

oxygen increase to above 12 mg/L on average in the San Joaquin seine region in August. All 
23

regions had individual readings above 12 mg/L and below 4 mg/L at various times throughout 

the year, though not consistently enough to be reflected in the monthly averages. Both extremes 

tended to occur February through June. This is likely due to agricultural nutrient inputs 

supporting increased primary production followed by increased bacterial respiration supported 

by excess nutrients or increased detritus from aquatic plants and algae (Dunne and Leopold 

1978).

Turbidity samples ranged from 0.1 to 520 NTU and 0.8 to 823 NTU during the 2014 and 2015

field seasons, respectively (Figures 12 and 13). In general, the turbidity was lower within the 

Central Delta and South Delta seine regions relative to other regions throughout most of 2014 

and lower in the South Delta and San Joaquin seine regions throughout most of 2015. In 

addition, the turbidity varied considerably within the San Pablo Bay Seine Region possibly due 

to wind and wave erosion during the spring and summer seasons. We also observed increased 

turbidity in December and February during the 2015 field season in all seine regions and trawl 

sites, possibly resulting from increased precipitation and discharge. 

Conductivity varied considerably among trawl sites and seine regions during the 2014 and 2015

field seasons (Figures 14 and 15). We observed that conductivity was highest across all months 

within the San Francisco and San Pablo Bay Seine Region as well as the Chipps Trawl site. This 

was expected because the San Francisco and San Pablo Bay Seine Region is the closest in 

proximity to the Pacific Ocean and is the seine region most similar to a marine environment. 

Conversely, the conductivity within the Lower Sacramento River and North Delta seine regions, 

and at the Sacramento and Mossdale trawl sites, were lower and more consistent relative to other 

monitoring locations, which may be due to these sites being less exposed to tidal exchange. The 

conductance within the Central Delta and South Delta seine regions, and at the Chipps Island 

Trawl Site, were the most variable within and among months, possibly due to agricultural inputs, 

water operations, and tidal exchange. Few distinct inter-annual patterns were observed. 
24

(B) 2014 Field season

Beach seine regions

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Region 2

(A) 2014 Field season

Trawl sites

Water temperature (°C)

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Mossdale Trawl Site

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul 

C S M

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul 

1 2 3 4 5 6 

C S M C S M C S M C S M C S M C S M C S M C S M C S M C S M C S M

1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 

Region 1

Region 2

Region 3

Region 4

Region 5

Region 6

Figure 8. Water temperature data collected by month during sampling at the (A) Chipps Island 

(C), Sacramento (S), and Mossdale (M) trawl sites and within the (B) Lower Sacramento River 

(Region 1), North Delta (Region 2), Central Delta (Region 3), South Delta (Region 4), Lower 

San Joaquin River (Region 5), and San Francisco and San Pablo Bay (Region 6) seine regions 

during the 2014 field season. The boxes represent the 25th and 75th percentiles, the line within 

the box represents the median, the whiskers represent the 10th and 90th percentiles, and points 

represent outliers.
25

(B) 2015 Field season

Beach seine regions

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Region 2

(A) 2015 Field season

Trawl sites

Water temperature (°C)

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Chipps Island Trawl Site

Sacramento Trawl Site

Mossdale Trawl Site

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul 

C S M

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul 

1 2 3 4 5 6 

C S M C S M C S M C S M C S M C S M C S M C S M C S M C S M C S M

1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 

Region 1

Region 2

Region 3

Region 4

Region 5

Region 6

Figure 9. Water temperature data collected by month during sampling at the (A) Chipps Island 

(C), Sacramento (S), and Mossdale (M) trawl sites and within the (B) Lower Sacramento River 

(Region 1), North Delta (Region 2), Central Delta (Region 3), South Delta (Region 4), Lower 

San Joaquin River (Region 5), and San Francisco and San Pablo Bay (Region 6) seine regions 

during the 2015 field season. The boxes represent the 25th and 75th percentiles, the line within 

the box represents the median, the whiskers represent the 10th and 90th percentiles, and points 

represent outliers.
26

(B) 2014 Field season

Beach seine regions

0

5

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20

Region 2

(A) 2014 Field season

Trawl sites

Dissolved oxygen (mg/L)

0

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Chipps Island Trawl Site

Sacramento Trawl Site

Mossdale Trawl Site

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul 

C S M

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul 

1 2 3 4 5 6 

C S M C S M C S M C S M C S M C S M C S M C S M C S M C S M C S M

1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 

Region 1

Region 2

Region 3

Region 4

Region 5

Region 6

Figure 10. Dissolved oxygen data collected by month during sampling at the (A) Chipps Island 

(C), Sacramento (S), and Mossdale (M) trawl sites and within the (B) Lower Sacramento River 

(Region 1), North Delta (Region 2), Central Delta (Region 3), South Delta (Region 4), Lower 

San Joaquin River (Region 5), and San Francisco and San Pablo Bay (Region 6) seine regions 

during the 2014 field season. The boxes represent the 25th and 75th percentiles, the line within 

the box represents the median, the whiskers represent the 10th and 90th percentiles, and points 

represent outliers. 
27

(B) 2015 Field season

Beach seine regions

0

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20

Region 2

(A) 2015 Field season

Trawl sites

Dissolved oxygen (mg/L)

0

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Sacramento Trawl Site

Mossdale Trawl Site

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul 

C S M

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul 

1 2 3 4 5 6 

C S M C S M C S M C S M C S M C S M C S M C S M C S M C S M C S M

1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 

Region 1

Region 2

Region 3

Region 4

Region 5

Region 6

Figure 11. Dissolved oxygen data collected by month during sampling at the (A) Chipps Island 

(C), Sacramento (S), and Mossdale (M) trawl sites and within the (B) Lower Sacramento River 

(Region 1), North Delta (Region 2), Central Delta (Region 3), South Delta (Region 4), Lower 

San Joaquin River (Region 5), and San Francisco and San Pablo Bay (Region 6) seine regions 

during the 2015 field season. The boxes represent the 25th and 75th percentiles, the line within 

the box represents the median, the whiskers represent the 10th and 90th percentiles, and points 

represent outliers.
28

(B) 2014 Field season

Beach seine regions

0

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500

Region 1

Region 2

Region 3

Region 4

Region 5

Region 6

Region 2

(A) 2014 Field season

Trawl sites

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Chipps Island Trawl Site

Sacramento Trawl Site

Mossdale Trawl Site

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul 

C S M

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul 

1 2 3 4 5 6 

C S M C S M C S M C S M C S M C S M C S M C S M C S M C S M C S M

1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 

Figure 12. Turbidity data collected by month during sampling at the (A) Chipps Island (C), 

Sacramento (S), and Mossdale (M) trawl sites and within the (B) Lower Sacramento River 

(Region 1), North Delta (Region 2), Central Delta (Region 3), South Delta (Region 4), Lower 

San Joaquin River (Region 5), and San Francisco and San Pablo Bay (Region 6) seine regions 

during the 2014 field season. The boxes represent the 25th and 75th percentiles, the line within 

the box represents the median, the whiskers represent the 10th and 90th percentiles, and points 

represent outliers. 
29

(B) 2015 Field season

Beach seine regions

0

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500

Region 2

(A) 2015 Field season

Trawl sites

Turbidity (NTU)

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Chipps Island Trawl Site

Sacramento Trawl Site

Mossdale Trawl Site

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul 

C S M

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul 

1 2 3 4 5 6 

C S M C S M C S M C S M C S M C S M C S M C S M C S M C S M C S M

1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 

Region 1

Region 2

Region 3

Region 4

Region 5

Region 6

Figure 13. Turbidity data collected by month during sampling at the (A) Chipps Island (C), 

Sacramento (S), and Mossdale (M) trawl sites and within the (B) Lower Sacramento River 

(Region 1), North Delta (Region 2), Central Delta (Region 3), South Delta (Region 4), Lower 

San Joaquin River (Region 5), and San Francisco and San Pablo Bay (Region 6) seine regions 

during the 2015 field season. The boxes represent the 25th and 75th percentiles, the line within 

the box represents the median, the whiskers represent the 10th and 90th percentiles, and points 

represent outliers.
30

(B) 2014 Field season; 

beach seine regions

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(A) 2014 Field season;

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Mossdale Trawl Site

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul 

1 2 3 4 5 6 

C S M C S M C S M C S M C S M C S M C S M C S M

1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 

Region 1

Region 2

Region 3

Region 4

Region 5

Region 6

C S M C S M C S M C S M

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul 

Figure 14. Conductivity data collected by month during sampling at the (A) Chipps Island (C), 

Sacramento (S), and Mossdale (M) trawl sites and within the (B) Lower Sacramento River 

(Region 1), North Delta (Region 2), Central Delta (Region 3), South Delta (Region 4), Lower 

San Joaquin River (Region 5), and San Francisco and San Pablo Bay (Region 6) seine regions 

during the 2014 field season. The boxes represent the 25th and 75th percentiles, the line within 

the box represents the median, the whiskers represent the 10th and 90th percentiles, and points 

represent outliers. The y-axis is presented on a common log scale. 
31

(B) 2015 Field season; 

beach seine regions

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1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul 

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul 

C S M C S M C S M C S M C S M C S M C S M C S M C S M C S M C S M C S M

Figure 15. Conductivity data collected by month during sampling at the (A) Chipps Island (C), 

Sacramento (S), and Mossdale (M) trawl sites and within the (B) Lower Sacramento River 

(Region 1), North Delta (Region 2), Central Delta (Region 3), South Delta (Region 4), Lower 

San Joaquin River (Region 5), and San Francisco and San Pablo Bay (Region 6) seine regions 

during the 2015 field season. The boxes represent the 25th and 75th percentiles, the line within 

the box represents the median, the whiskers represent the 10th and 90th percentiles, and points 

represent outliers. The y-axis is presented on a common log scale.
32

Fish Assemblage

A total of 519,813 fishes, representing 82 species, was collected within samples (beach seines 

and trawls) used for assemblage analyses during the 2014 and 2015 field seasons (does not 

include marked or unidentified fish; Tables A.3 and A.4). Sixty-three percent (n=328,642) of the 

fishes were observed during the 2014 field season. Approximately 77% (n=256,256) and 86% 

(n=166,020) of the fishes captured during the 2014 and 2015 field seasons, respectively, were 

identified as species not native to the San Francisco Estuary. Of the 79 species observed, from

the 2014 field season the most abundant species were the Inland Silverside Menidia beryllina, 

juvenile Chinook Oncorhynchus tshawytscha, Red Shiner Cyprinella lutrensis, Threadfin Shad 

Dorosoma petenense, and American Shad Alosa sapidissima, comprising 89% of the total annual 

catch. For 2015, this changed slightly with dominant species being Inland Silverside, Threadfin 

Shad, American Shad, Red Shiner, and Sacramento Sucker, comprising 84% of the catch.

In general, anadromous-pelagic-nonnative fishes dominated the catch at the Chipps Island Trawl 

Site during the 2014 and 2015 field seasons (Figure 16). Within this group, the American Shad 

was the most common species observed at the Chipps Island Trawl Site, and comprised 63% 

(n=9,149) and 59% (n=7,462) of the fishes captured during the 2014 and 2015 field seasons, 

respectively (Tables A.3 and A.4). Anadromous-pelagic-nonnative fishes (e.g., American Shad) 

dominated the catch at the Chipps Island Trawl Site from January and February, and June to 

December (Figure 16), with anadromous-pelagic-native fishes (e.g., juvenile Chinook) 

dominating the catch during most of the months between March and May in 2014, and April 

2015. The mean yearly CPUE estimates suggested that anadromous-pelagic-native fishes have 

declined steadily at the Chipps Island Trawl Site since the 1996 field season (Figure 16C). 

Relative to 2015, the 2014 field year displayed low seasonal variability in water discharge, and 

this may explain some of the differences between in-community composition of the catch 

(measured as CPUE) between the two years. The low flows in 2014 would have favored some 

nonnative pelagic species and the near absence of juvenile salmon in the catch until March 

suggests that low flows delayed downriver movement. In contrast, the 2015 field season 

exhibited higher seasonal variation in flow and showed an earlier (December) and overall more 

protracted occurrence of juvenile salmon in the trawls. 

During the 2014 and 2015 field seasons, the most common species captured at the Sacramento 

Trawl Site was juvenile Chinook (81%, n=25,213; Tables A.3 and A.4). We observed that these 

anadromous-pelagic-native fishes were generally captured between February and April in 2014, 

and were more variable in 2015 with highest CPUE in December, February and April. CPUE 

peaked in February during both field seasons (Figure 17). Nonnative anadromous and resident 

pelagic fishes were observed in proportionally lower densities from February to May in 2014, 

and from February to April in 2015. The notable difference between 2014 and 2015 was the 

historical high in CPUE of pelagic natives (i.e. juvenile Chinook) and pelagic nonnatives in 

2014. Part of this difference may be due to the contrasting seasonal flow regimes between the 

two years, with the 2014 field year displaying low seasonal variability in water discharge relative 

to 2015 which would have favored nonnative pelagic species. Moreover, juvenile Chinook from 

the 2014 field season first occurred in February, whereas they were observed in November 2015, 

suggesting that higher flow regimes in 2015 initiated earlier downriver migration and a more 

temporally protracted downriver migration of the population. 
33

The Inland Silverside was overall the most common species observed and comprised 51% 

(n=268,425) of the fishes captured at the Mossdale Trawl Site and in the Lower Sacramento 

River, North Delta, Central Delta, South Delta, and Lower San Joaquin River seine regions 

during the 2014 and 2015 field seasons (Tables A.3 and A.4). As a result, the pelagic-nonnative 

fishes dominated the observed fish assemblage within the Mossdale Trawl Site and most seine 

regions throughout both field seasons (Figures 18–20). We observed the majority of fishes at the 

Mossdale Trawl Site in January and August for 2014, and June and July in 2015 (Figure 18). 

Pelagic native fishes dominated the observed assemblage in February to April of the 2014 field 

season when anadromous-pelagic-native fishes (e.g., juvenile Chinook) were present, whereas 

this was only observed in December 2014 and February in the 2015 field season. In addition to 

pelagic-nonnative fishes, the mean monthly CPUE estimates suggest that the fish assemblage 

within the North Delta and Lower Sacramento River seine regions contained considerable 

densities of anadromous-pelagic-native fishes from February to March and benthic-native fishes 

(e.g., lamprey and Sacramento Sucker; Tables A.3 and A.4) from April to June (Figure 19). The 

mean yearly CPUE estimates among beach seine regions and the Mossdale Trawl demonstrated 

that fish densities for anadromous pelagic native and pelagic non-natives were historically high 

during the 2014 field season, exceeding levels observed since 2000. Following the 2014 field 

season, CPUE sharply decreased to levels that were comparable to the decadal low level 

observed in 2010 (Figures 18 and 20). 

Within the San Francisco and San Pablo Bay Seine Region, the Topsmelt Atherinops affinis was 

the most common fish species observed and comprised 61% (n=10,372) of all fishes captured 

during both the 2014 and 2015 field seasons (Tables A.3 and A.4). The mean monthly CPUE 

estimates suggest that pelagic-nonnative fishes were observed in higher proportions within and 

among all field seasons relative to other assemblages groups (Figures 19 and 20). Nearly all 

fishes observed within this seine region, including Topsmelt, are considered marine fish,

presumably due to the higher conductivity within the region (Figures 14 and 15). In general, we 

cannot discern any temporal patterns from monthly or yearly CPUE estimates in this region for 

any fish assemblage group due to relatively low catch numbers. 

The 2014 field season showed substantively higher CPUE in both pelagic native and non-native 

species, both from 2015 and from previous years’ catch to 2000 (Figures 17-20). For pelagic 

native species this was largely due to very high CPUE of juvenile Chinook from seine regions 1, 

2 and 3 and the Sacramento trawl site between February and April. For pelagic non-native fishes, 

the overall greater CPUE in the 2014 field was attributed to very high catches of Inland 

Silversides and Threadfin Shad from the South Delta (Region 5, Mossdale) in both seines and 

trawls, and Red Shiners from seines. The substantial difference between the two years may be 

attributed to the difference in their respective flow regimes, where 2014 exhibited a lower annual 

flow and reduced seasonal variability relative to the 2015 field season. As seen between 2014 

and 2015, both the magnitude and timing of seasonal flows across the region would have varying 

effects on the distribution and abundance of certain species. For example, in 2014 the lack of 

distinguished peak flow events in the winter months likely influenced the first occurrence of 

downriver migrating juvenile Chinook, which occurred later in the field season (February) 

relative to 2015 (December)(Figure 17C). Moreover, reduced flows and retention of juvenile 

Chinook up river may have caused a greater pulse event once fish started to migrate downstream, 
34

which is apparent from the sudden and substantive increase in CPUE of pelagic natives in 

February and March in 2014 relative to 2015. The high CPUE of both native and non-native 

pelagics from the 2014 field season may have been attributed to lower river volumes and 

increased catch efficiencies, and this is evidenced by the fact that CPUE of both native and nonnative pelagics showed the greatest differences in CPUE between 2014 and 2015 in beach seines 

and trawls from the Sacramento River, whereas this difference between years was not observed 

in the lower Delta where volumes are more tidally influenced. 

The overall higher densities of fishes in the 2014 field season correspond to reduced and delayed 

high peak flows occurring later in the year than in 2015 (around 400 m3/sec in March of the 2014 

field season for Delta Outflow and the discharge at the Sacramento River at Freeport versus 880 

m

3

/sec in December of 2015; Figures 16–20). The increased discharge observed at the 

Sacramento Trawl Site in 2015 may also explain the earlier occurrence of anadromous-pelagicnative fishes. In contrast, the increased outflow in February through March may explain the 

overall increased fish densities captured at Chipps Island in 2014. The later flows in the 2014 

field season may have also extended the occurrence of the anadromous-pelagic-native fishes in 

the beach seines (Figure 19).
35

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Pelagic-nonnative

Figure 16. The mean monthly and yearly CPUE (bars) of juvenile fish assemblages captured in 

MWTRs at the Chipps Island Trawl Site, and the estimated mean monthly and yearly Delta

outflow (solid line) during the (A) 2014, (B) 2015, and (C) 1995 through 2015 field seasons.

Year
36

(A) 2014 field season

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(C) 2000 - 2015 field seasons

Figure 17. The mean monthly and yearly CPUE of juvenile fish assemblages captured in 

MWTRs (solid bars) and KDTRs (striped bars) at the Sacramento Trawl Site, and the mean 

monthly and yearly Sacramento River discharge at Freeport (solid line) during the (A) 2014, (B) 

2015, and (C) 2000 through 2015 field seasons.
37

(A) 2014 field season

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(C) 2004 - 2015 field seasons

Figure 18. The mean monthly and yearly CPUE (bars) of juvenile fish assemblages captured in 

KDTRs at the Mossdale Trawl Site, and the mean monthly and yearly San Joaquin River 

discharge at Vernalis (solid line) during the (A) 2014, (B) 2015, and (C) 2004 through 2015 field 

seasons.
38

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2012_CPUE_PN 

2012_CPUE_PNN 

Col 12 vs 2012_Outflow 

2012_Freeport 

2012_Vernalis 

Region:

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul

1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 

Region:

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul

1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 

(B) 2015 field season

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Anadromous-benthic-native

Anadromous-pelagic-nonnative

Anadromous-pelagic-native

Benthic-native

Benthic-nonnative

Pelagic-native

Pelagic-nonnative

Figure 19. The mean monthly CPUE (bars) of juvenile fish assemblages captured within the 

Lower Sacramento River (1), North Delta (2), Central Delta (3), South Delta (4), Lower San 

Joaquin River (5), and San Francisco and San Pablo Bay (6) beach seine regions, and the 

estimated mean monthly and yearly Delta outflow (dashed line), Sacramento River discharge at 

Freeport (solid line), and San Joaquin River discharge at Vernalis (dotted line) during the (A) 

2014 and (B) 2015 field seasons.
39

CPUE (fish/10,000 m

3

)

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 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Region: 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6

Benthic-native

Benthic-nonnative

Pelagic-native

Pelagic-nonnative

Anadromous-benthic-native

Anadromous-pelagic-native

Anadromous-pelagic-nonnative

Figure 20. The mean yearly CPUE (bars) of juvenile fish assemblages captured within the Lower 

Sacramento River (1), North Delta (2), Central Delta (3), South Delta (4), Lower San Joaquin 

River (5), and San Francisco and San Pablo Bay (6) beach seine regions, and the estimated mean 

monthly and yearly Delta outflow (dashed line), Sacramento River discharge at Freeport (solid 

line), and San Joaquin River discharge at Vernalis (dotted line) during the 2000 through 2015

field seasons.

Juvenile Chinook Salmon

We captured 50,646 and 5,399 juvenile Chinook during the 2014 and 2015 field seasons, 

respectively (Tables A.3 and A.4). During the 2014 field season, 49,490 individuals were 

unmarked, of which 0.37% (n=181) were identified as winter-run sized, 94.66% (n=46,845) as 

fall-run sized, 4.96% (n=2,457) as spring-run sized, and 0.01% (n=7) as late fall-run sized using 

the length at date criteria; a total of 157 individuals were not raced (Table A.3). Of the 1066

marked (i.e., clipped adipose fin) juvenile Chinook recovered during 2014, 98% (n=1052) 

contained a readable CWT (Table A.20). During the 2015 field season, 4,578 individuals were 

unmarked, of which 2.56% (n=117) were identified as winter-run sized, 58.56% (n=2,681) as 

fall-run sized, 38.16% (n=1,747) as spring-run sized, and 0.72% (n=33) as late fall-run sized 

Chinook (Table A.4). Of the 726 marked juvenile Chinook recovered during 2015, 96% (n=700) 

contained a readable CWT (Table A.21). 

We recovered a total of 31 and 174 marked juvenile winter-run Chinook containing a CWT 

during the 2014 and 2015 field seasons, respectively, within the Sacramento Trawl Site, and the 

Chipps Island Trawl Site. All recovered CWT winter-run Chinook had been released by the 

Livingston Stone National Fish Hatchery, which released 193,264 (190,905 marked and with a 

CWT) and 609,311 (590,623 marked and with a CWT) juvenile winter-run Chinook in the 

Year
40

Central Valley during the 2014 and 2015 field seasons, respectively (PSMFC 2017). The number 

of marked and tagged fish reported in parentheses comes from the hatchery and accounts for tag 

loss before release.

We recovered a total of 325 and 47 marked juvenile spring-run Chinook tagged with CWTs

during the 2014 and 2015 field seasons, respectively, within the Lower Sacramento River, North 

Delta, and Central Delta seine regions, and the Sacramento, Chipps Island, and Mossdale Trawl 

Sites (Tables A.20 and A.21). All recovered CWT spring-run Chinook had been released by the 

Feather River Fish Hatchery, which released 2,296,788 (2,275,716 marked and with a CWT) and 

1,763,479 (1,745,811 marked and with a CWT) juvenile spring-run Chinook in the Central 

Valley and the Suisun and San Pablo Bays during the 2014 and 2015 field seasons (PSMFC 

2017). 

We recovered a total of 549 and 464 marked juvenile fall-run Chinook containing a CWT during 

the 2014 and 2015 field seasons, respectively, within the Lower Sacramento River, North Delta, 

Central Delta, and San Francisco-San Pablo Bay seine regions, the Sacramento, Chipps Island, 

and Mossdale Trawl Sites (Tables A.20 and A.21). In the 2014 field season, 28,279,571

(7,671,718 marked and with a CWT) hatchery reared juvenile fall-run Chinook were released 

into the Central Valley (48.5%) and the San Francisco area bays (51.5%) in the combined release 

efforts of the Coleman National Fish Hatchery, Feather River Fish Hatchery, Mokelumne River 

Fish Hatchery, Nimbus Fish Hatchery, and Merced River Fish Facility (PSMFC 2017). In the 

2015 field season, 26,080,867 (6,593,909 marked and with a CWT) hatchery reared juvenile fallrun Chinook were released into the Central Valley (65.7%) or the San Francisco area bays 

(34.3%) in the combined release efforts of the Coleman National Fish Hatchery, Feather River 

Fish Hatchery, Mokelumne River Fish Hatchery, Nimbus Fish Hatchery, and Merced River Fish 

Facility (PSMFC 2017). 

We recovered a total of 147 and 15 marked juvenile late fall-run Chinook containing a CWT 

during the 2014 and 2015 field seasons, respectively, within the Lower Sacramento River and 

North Delta seine regions, the Sacramento Trawl Site, and the Chipps Island Trawl Site (Tables 

A.20 and A.21). All recovered CWT late fall-run Chinook were released by the Coleman 

National Fish Hatchery, which released 984,977 (960,075 marked) and 1,094,719 (1,056,322

marked) juvenile late fall-run Chinook in the Central Valley during the 2014 and 2015 field 

seasons (PSMFC 2017). Nearly all of the juvenile Chinook captured using beach seines since the 

2000 field season were estimated to be of natural origin using equations 1 and 2 (see “Estimate 

of Hatchery and Natural Origin Juvenile Chinook Salmon” section; 93.5% natural origin, 1.4% 

hatchery origin, 5.0% unknown origin). While hatcheries typically release smolt-sized fish and 

few fry (PSMFC 2017), both fry- and smolt-sized Chinook were observed in the beach seines 

(see “Fork Length Distributions” section). 

Winter-Run Distribution and Relative Abundance

Nearly 100% of all juvenile winter-run Chinook produced by the Livingston Stone National Fish 

Hatchery have been released marked and containing a CWT since production began in 1995 

(PSMFC 2017). We estimated that natural origin juvenile winter-run sized Chinook were 
41

captured in relatively low numbers at the Chipps Island Trawl Site, the Sacramento Trawl Site, 

and in the Lower Sacramento River, North Delta, Central Delta, and South Delta seine regions 

during the 2014 and 2015 field seasons (Figures 21–24). Although genetic analyses have 

determined that the river LDC is fairly accurate for winter-run Chinook designation, it should be 

noted that significant numbers of individuals from other races are included within the winter-run 

criteria (Pyper et al. 2013), thus the abundance is significantly over-estimated using the river 

LDC. 

Consistent with the 2012 and 2013 field seasons (Barnard et al. 2015), in both 2014 and 2015 

winter-run sized juvenile Chinook were generally captured from November through April at the 

Sacramento Trawl Site and December through April at the Chipps Island Trawl Site (Figures 21

and 22). The CPUE at the Sacramento Trawl Site peaked in February into March during the 2014 

and 2015 field seasons. Conversely, the CPUE at the Chipps Island Trawl Site peaked during 

March in 2014, and February during the 2015 field season. There was no discernible trend with 

respect to a time-lag in peak CPUE at the Sacramento Trawl Site and the Chipps Island Trawl 

Site during both years. The Sacramento River discharge, on average, showed a gradual increase 

from January and peaking in March of the 2014 field season, whereas the 2015 field season 

showed higher flow variability and higher peak flows in December and February. The influence 

of flow regimes between 2014 and 2015 can be seen in the strong difference in timing of winterrun juvenile Chinook capture, with the 2015 field year showing a more protracted distribution 

from November to April at Sacramento and December to April in Chipps, whereas 2014 showed 

occurrences in February and March at Sacramento, and February to April at Chipps (Figures 21

and 22). The mean yearly CPUE at the Sacramento Trawl Site has increased considerably since 

the record low observed during the 2011 field season (Figure 22), and mean yearly CPUE at the 

Chipps Island Trawl Site increased in 2014 and nearly doubled in the 2015 field season (Figure 

21).

Estimated natural origin winter-run sized Chinook were captured using beach seines in February 

and March during the 2014 field season, whereas their occurrence in 2015 was more seasonally 

protracted to the months of November, December, February and March (Figure 23). We did not 

observe any marked winter run in the beach seines during the 2014 field season. In 2015, the 

mean monthly CPUE of natural origin winter-run juveniles peaked in the Lower Sacramento 

River and North Delta seine regions in December compared to February during the 2014 field 

season (Figure 23). Conversely, the monthly CPUE in the Central Delta and South Delta seine 

regions peaked either in February (2015) or March (2014). The mean yearly CPUE estimates 

suggested that natural origin juvenile winter-run Chinook were consistently observed in higher 

densities within the Lower Sacramento River Seine Region relative to other seine regions since 

the 2000 field season (Figure 24).
42

1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

0.00

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R1_2012_CPUE_FSLF_Est_Wld 

R1_2012_CPUE_FSLF_Est_Hatch 

R1_2012_CPUE_FSLF_CWT 

Sample_Month vs 2012_Freeport_Monthly 

(B) 2015 field season

Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul

CPUE (fish/10,000 m

3

)

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Estimated natural origin

Estimated hatchery origin

Marked

(C) 1995 - 2015 field seasons

Figure 21. The mean monthly and yearly CPUE (bars) of juvenile hatchery winter-run and 

winter-run sized Chinook Salmon captured in MWTRs at the Chipps Island Trawl Site, and the 

estimated mean monthly and yearly Delta outflow (solid line) during the (A) 2014, (B) 2015, and 

(C) 1995 through 2015 field seasons.

Year
43

(A) 2014 field season

Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul

0.0

0.1

0.2

0.3

0

200

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(B) 2015 field season

Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul

CPUE (fish/10,000 m

3

)

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Mean discharge (m

3/sec)

0

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2000 2002 2004 2006 2008 2010 2012 2014

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1400

Estimated natural origin

Estimated hatchery origin

Marked

(C) 2000 - 2015 field seasons

Figure 22. The mean monthly and yearly CPUE of juvenile hatchery winter-run and winter-run 

sized Chinook Salmon captured in MWTRs (solid bars) and KDTRs (striped bars) at the 

Sacramento Trawl Site, and the mean monthly and yearly Sacramento River discharge at 

Freeport (solid line) during the (A) 2014, (B) 2015, and (C) 2000 through 2015 field seasons.

Year
44

(A) 2014 field season

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(B) 2015 field season

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Region:

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul

1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 

Estimated natural origin

Estimated hatchery origin

Marked

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul

1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 

Figure 23. The mean monthly CPUE (bars) of hatchery and juvenile winter-run sized Chinook 

Salmon captured within the Lower Sacramento River (1), North Delta (2), Central Delta (3), 

South Delta (4), Lower San Joaquin River (5), and San Francisco and San Pablo Bay (6) beach 

seine regions, and the estimated mean monthly and yearly Delta outflow (dashed line), 

Sacramento River discharge at Freeport (solid line), and San Joaquin River discharge at Vernalis 

(dotted line) during the (A) 2014 and (B) 2015 field seasons.

Month
45

CPUE (fish/10,000 m

3

)

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Mean discharge (m

3/sec)

0

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 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Region: 123456 123456 123456 123456 123456 123456 123456 123456 123456 123456 123456 123456 123456 123456 

Estimated natural origin

Estimated hatchery origin

Marked

123456 123456 

Figure 24. The mean yearly CPUE (bars) of juvenile hatchery winter run and winter-run sized 

Chinook captured within the Lower Sacramento River (1), North Delta (2), Central Delta (3), 

South Delta (4), Lower San Joaquin River (5), and San Francisco and San Pablo Bay (6) beach 

seine regions, and the estimated mean monthly and yearly Delta outflow (dashed line), 

Sacramento River discharge at Freeport (solid line), and San Joaquin River discharge at Vernalis 

(dotted line) during the 2000 through 2015 field seasons.

Fall-, Late Fall-, and Spring-Run Distribution and Relative Abundance

We captured juvenile fall-, late fall-, or spring-run sized Chinook in nearly all seine regions and 

trawl sites during the 2014 and 2015 field seasons (Tables A.3 and A.4). Until the 2000 field 

season, hatchery fish were often released in groups within the watershed that did not have any 

marked individuals containing a CWT (Kevin Niemela, USFWS, personal communication; 

PSMFC 2017). As a result, we were unable to determine the origin of large numbers of fish 

captured at the Chipps Island and Sacramento trawl sites prior to the 2000 field season. 

At the Chipps Island Trawl Site, juvenile fall-, late fall-, or spring-run sized Chinook were 

captured between February and May in 2014, and between December and May in the 2015 field 

season (Figure 25). Individuals were captured from February through June at the Sacramento 

Trawl Site in the 2014 field season whereas the occurrence of juvenile Chinook in the 2015 field 

season commenced as early as November and continued into May. This difference between years 

may be attributed to the difference in timing and magnitude of peak flow events, where 2015 

showed overall lower discharge but more pronounced peak flow events between the months of 

November to June relative to 2014 (Figure 26). We observed a greater proportion of hatchery 

fish (estimated and marked) relative to natural origin fish during the 2015 season at Chipps 

Island, whereas the Sacramento trawl site generally showed higher proportions of estimated 

natural origin fish. In the 2014 field season fish of natural origin dominated at both trawl sites. 

Year
46

The majority of fish captured at the Mossdale Trawl Site that occurred between March and June 

were considered to be natural origin due to few hatchery releases occurring in the San Joaquin 

Basin (PSMFC 2017; Figure 27). At all the trawl sites, the peak-mean monthly CPUE 

representing natural origin individuals occurred from January through May for 2014, and from 

February through April for the 2015 field season. The mean yearly CPUE at the Chipps Island 

Trawl Site has declined annually since the 2011 field season, however the 2014 CPUE was 

nearly equal to the historical averages (Figures 25 and 28). This assumes that catch efficiency at 

Chipps Island did not vary between variable flow years of 2011 (a high flow year) and 2012 to 

2015 (low flow years; Table A.19). The mean yearly CPUE at the Sacramento trawl site in 2014 

was a historic high from 2000, which was subsequently followed by historically low CPUE in 

2015 (Figure 26). From the Mossdale Trawl Site, CPUE in the 2014 field season had decreased 

over three-fold from the 2013 field year, and CPUE further dropped from 2014 to historically 

low numbers from 2004 (Figures 26 and 27). Although these races are grouped for consistency 

within this report, all juvenile Chinook captured at Mossdale are assumed to be fall-run. 

Estimated natural origin juvenile fall-, late fall-, or spring-run Chinook were generally captured 

using beach seines between February and May during the 2014, and November and April 2015

field seasons (Figure 29). We observed few marked fish during both field seasons. The mean 

monthly CPUE of natural origin fall-, late fall-, or spring-run Chinook peaked in the Lower 

Sacramento River and North Delta seine regions during February and March in 2014, and 

December to March in 2015. The mean yearly CPUE estimates suggested that natural origin 

juvenile fall-, late fall-, or spring-run Chinook were consistently observed in higher densities 

within the Lower Sacramento River and North Delta seine regions, and to a lesser extent the 

Central Delta seine regions, relative to other seine regions since the 2000 field season (Figure 

30).
47

(A) 2014 field season

Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul

0

1

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4

5

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(B) 2015 field season

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6 Mean discharge (m

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1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

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Estimated natural origin

Estimated hatchery origin

Marked

Unknown

(C) 1995 - 2015 Field Seasons

Figure 25. The mean monthly and yearly CPUE (bars) of juvenile fall-, late fall-, and spring-run 

Chinook Salmon captured in MWTRs at the Chipps Island Trawl Site, and the estimated mean 

monthly and yearly Delta outflow (solid line) during the (A) 2014, (B) 2015, and (C) 1995 

through 2015 field seasons. 

Year
48

(A) 2014 field season

Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul

0

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Marked

Unknown origin

(B) 2015 field season

Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul

CPUE (fish/10,000 m

3

)

0

1

2

4

5 Mean discharge (m

3/sec)

0

200

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600

800

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1400

(C) 2000 - 2015 field seasons

Figure 26.The mean monthly and yearly CPUE (bars) of juvenile fall-, late fall-, and spring-run 

Chinook Salmon captured in MWTRs (solid bars) and KDTRs (striped bars) at the Sacramento 

Trawl Site, and the mean monthly and yearly Sacramento River discharge at Freeport (solid line) 

during the (A) 2014, (B) 2015, and (C) 2000 through 2015 field seasons. 

Year
49

(A) 2014 field season

Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul

0.00

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5.00

6.00

0

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Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul

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3

)

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Mean discharge (m

3/sec)

0

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2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

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3.5

0

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250

300

Estimated wild origin

Estimated hatchery origin

Marked

Unknown origin

(C) 2004 - 2015 field seasons

Figure 27. The mean monthly and yearly CPUE (bars) of juvenile fall-, late fall-, and spring-run 

sized Chinook Salmon captured in KDTRs at the Mossdale Trawl Site, and the mean monthly 

and yearly San Joaquin River discharge at Vernalis (solid line) during the (A) 2014, (B) 2015, 

and (C) 2004 through 2015 field seasons. Juvenile Chinook Salmon captured at Mossdale are 

assumed to be fall-run only.

Year
50

1980 1985 1990 1995 2000 2005 2010 2015

CPUE (fish/10,000 m

3

)

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2

4

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8

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12

14

Mean discharge (m

3/sec)

0

500

1000

1500

2000

2500

Estimated natural origin 3000

Estimated hatchery origin

Marked

Unknown origin

Figure 28. Mean yearly CPUE (bars) of juvenile fall-, late fall-, and spring-run sized Chinook 

Salmon captured in MWTRs at the Chipps Island Trawl Site, and the estimated mean monthly 

and yearly Delta outflow (solid line) during April–June of the 1978–2015 field seasons.

(A) 2014 field season

0

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Region:

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul

1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 

(B) 2015 field season

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1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 

Estimated natural origin

Estimated hatchery origin

Marked

Unknown origin

Figure 29. The mean monthly CPUE (bars) of juvenile fall-, late fall-, and spring-run sized

Chinook Salmon captured within the Lower Sacramento River (1), North Delta (2), Central Delta 

(3), South Delta (4), Lower San Joaquin River (5), and San Francisco and San Pablo Bay (6) 

beach seine regions, and the estimated mean monthly and yearly Delta outflow (dashed line), 

Sacramento River discharge at Freeport (solid line), and San Joaquin River discharge at Vernalis 

(dotted line) during the (A) 2014 and (B) 2015 field seasons.

Month
51

CPUE (fish/10,000 m

3

)

0

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6000

7000

Mean discharge (m

3/sec)

0

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 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Region: 123456 123456 123456 123456 123456 123456 123456 123456 123456 123456 123456 123456 123456 123456 

Estimated natural origin

Estimated hatchery origin

Marked

Unknown origin

123456 123456 

Figure 30. The mean yearly CPUE (bars) of juvenile fall-, late fall-, and spring-run sized 

Chinook Salmon captured within the Lower Sacramento River (1), North Delta (2), Central Delta 

(3), South Delta (4), Lower San Joaquin River (5), and San Francisco and San Pablo Bay (6) 

beach seine regions, and the estimated mean monthly and yearly Delta outflow (dashed line), 

Sacramento River discharge at Freeport (solid line), and San Joaquin River discharge at Vernalis 

(dotted line) during the 2000 through 2015 field seasons.

Absolute Abundance

Among the 130 release groups used to estimate the TRR ̅̅̅̅̅̅ at the Chipps Island Trawl Site, 

12,655,350 fish were marked with a CWT (PSMFC 2017). Release groups ranged in size from 

22,911 to 717,966 individuals. The TRR ̅̅̅̅̅̅ at the Chipps Island Trawl Site was estimated to be 

0.48% ± 0.08% (mean ± 95% CI), using CWT recoveries from 1989 to 2015. The duration of 

recoveries of CWT fish within a release group spanned, on average, 10.1 days.

We used 42 release groups to estimate the TRR ̅̅̅̅̅̅ of the MWTR at the Sacramento Trawl Site. 

Within these release groups, 2,398,810 fish were marked with a CWT. Release groups ranged in 

size from 34,480 to 104,516 individuals. The duration of recoveries of CWT fish within a release 

group spanned, on average, 10.8 days. Two of the release groups did not have any individuals 

captured at the site. The TRR ̅̅̅̅̅̅ of the Sacramento MWTR was estimated to be 0.82% ± 0.35%, 

using CWT releases from 1988 to 2009. We used 5 release groups to estimate the TRR ̅̅̅̅̅̅ of the 

KDTR at the Sacramento Trawl Site, where a total of 300,960 fish were marked with a CWT 

(PSMFC 2015). Release groups ranged in size from 48,987 to 69,490 individuals. The duration 

of recoveries of CWT fish within a release group spanned, on average, 4.9 days. The TRR ̅̅̅̅̅̅ of the 

KDTR was estimated to be 0.74% ± 0.87% between 1996 and 2006. 

Year
52

There were 53 release groups used to estimate the TRR ̅̅̅̅̅̅ at the Mossdale Trawl Site. Among these 

release groups, 438,529 individuals were marked either with stain dye (Steve Tsao, CDFW, 

personal communication) or an adipose fin clip and contained a CWT (PSMFC 2017). Release 

groups ranged in size from 1,195 to 74,411 individuals. The TRR ̅̅̅̅̅̅ was estimated to be 2.88% ± 

3.00%, using CWT and stain dye releases from 1997 to 2015. The duration of recoveries of 

marked fish within a release group spanned, on average, 1 day. Six of the release groups did not 

have any recoveries. While the TRR ̅̅̅̅̅̅ rate for the CWT groups (0.64% ± 0.83%) at Mossdale was 

comparable with the estimate for the Chipps Island and Sacramento trawl sites (0.48% ± 0.08% 

and 0.82% ± 0.35%, respectively; see above), the TRR ̅̅̅̅̅̅ of the stain dye groups were considerably 

higher (6.52% ± 4.93%). The increased recoveries may be due to unintentional targeting of 

marked fish or a time effect. In general, CWT releases at Mossdale occurred at random relative 

to sampling at the Mossdale Trawl Site, whereas spray dye fish were released at the beginning of 

a sample day (SJRGA 2009). 

The TRR ̅̅̅̅̅̅ had a negative lower 95% confidence limit for both the Sacramento Trawl Site 

(KDTR) and the Mossdale Trawl Site, which is due to relatively small sample sizes coupled with 

considerable variation among samples. Because a negative or zero value of TRR ̅̅̅̅̅̅ results in an 

absolute abundance of infinity, and the lower TRR ̅̅̅̅̅̅ confidence limit was used to estimate the 

upper absolute abundance confidence limit, we assigned the lower TRR ̅̅̅̅̅̅ confidence limit as 

0.10% in order to provide absolute abundance confidence limits. This value was chosen based on 

a conservative comparison to the lower TRR ̅̅̅̅̅̅ confidence limits at the Chipps Island and 

Sacramento (MWTR) trawl sites (0.40% and 0.47%, respectively; see above). We highly 

recommend further investigation of the efficiency of each of the trawls to obtain more precise 

and accurate absolute abundance estimates that can be used to inform future management 

decisions within the San Francisco Estuary and its watershed.

We estimated, on average, a total of 172,753 (83% natural origin, 16% marked) and 260,630

(17% natural origin, 82% marked) juvenile winter-run sized Chinook immigrating into the Delta 

at the Sacramento Trawl Site during the 2014 and 2015 field seasons, respectively (Figure 31). 

However, a total of 243,554 (80% natural origin, 20% marked) and 367,238 (31% natural origin, 

69% marked) juvenile winter-run sized Chinook were estimated to emigrate from the Delta at 

Chipps Island during the 2014 and 2015 field seasons, respectively (Figure 32). Since we 

estimated that more winter-run sized Chinook exited the Delta than entered the Delta in 2014 and 

2015, no reproduction of winter-run Chinook can occur in the Delta, and no hatchery releases of 

winter-run Chinook were made downstream of the Sacramento Trawl Site; from our data we 

believe that either the absolute abundance of winter-run Chinook at Chipps Island is overestimated or the absolute abundance at the Sacramento Trawl Site is under-estimated. It might be 

more likely that the absolute abundance at Chipps Island is over-estimated, since the river LDC 

has been shown to over-estimate a higher number of genetic winter-run at Chipps Island than at 

the Sacramento Trawl Site (Dekar et al. 2013). Regardless, it is apparent that the abundance of 

winter-run sized Chinook at Chipps Island is highly variable and has declined considerably since 

the 1990s (Figure 32). 

The mean yearly absolute abundance of all juvenile fall-, late fall-, and spring-run sized Chinook 

immigrating into the Delta at Sacramento was estimated to be 38,409,509 and 1,580,919 

individuals during the 2014 and 2015 field seasons, respectively (Figures 33 and 34). We 
53

estimated, on average, a total of 37,946,318 (98.2% natural origin, 1.1% hatchery origin, 0.5% 

marked) and 1,555,565 (92.3% natural origin, 0.02% hatchery origin, 7.6% marked) juveniles at 

the Sacramento Trawl Site during the 2014 and 2015 field seasons (Figure 33). Additionally, 

463,191(100% natural origin) and 25,354 (96.4% natural origin, 3.5 marked) juveniles were 

estimated at the Mossdale Trawl Site during the 2014 and 2015 field seasons (Figure 34). At the 

Chipps Island Trawl Site, we estimated a total of 9,770,455 (71.9.5% natural origin, 19.3% 

hatchery origin, 8.7% marked) and 7,430,738 (23.7% natural origin, 50.6% hatchery origin, 

25.6% marked) juveniles emigrating from the Delta during the 2014 and 2015 field seasons 

(Figure 35).

The absolute abundance estimates for juvenile Chinook presented in this report likely contain 

bias from several sources, in addition to potentially inaccurate race designations caused by the 

application of the LDC. Firstly, we assumed that unmarked individuals were never recaptured. 

However, nine CWT individuals in 2014 and five CWT individuals in 2015 that were released 

downstream of Chipps Island (San Pablo Bay) were captured by the Chipps Island MWTR 

(Tables A.20 and A.21). This points to the possibility of recapturing fish multiple times at one 

location, a violation of our assumption. Therefore, our abundance estimates may be overestimated to an unknown degree. Secondly, we may have under-estimated the absolute 

abundance of juvenile Chinook at each of the trawl sites due to the possible size selectivity of the 

MWTR’s and KDTR’s cod end design and mesh. Thirdly, we assumed that juvenile Chinook 

were equally distributed in time, which is unlikely due to diel migratory patterns. Several studies

have shown primarily nocturnal migratory behavior in juvenile Chinook (Gaines and Martin 

2002; Williams 2006 and references therein), while some studies in the Delta have provided 

evidence for diurnal migration of juvenile Chinook during the spring (Buchanan 2015; Wilder 

and Ingram 2006). While Bradford and Higgins (2001) mostly observed nocturnal activity, 

additional observations of a variety of diel activity patterns in the Bridge River of British 

Columbia led them to conclude that diel activity is caused by individual fish responding to finescale habitat attributes and is difficult to generalize. Given that the DJFMP only samples during 

the day, any diel activity patterns of juvenile Chinook could produce an unknown effect on the 

estimate of absolute abundance at all sampling locations. More investigation is needed to 

understand the effect of diel migratory patterns of juvenile Chinook on catch efficiency.
54

Figure 31. Mean absolute abundance estimates and their 95% confidence intervals for juvenile 

winter-run sized Chinook Salmon at the Sacramento Trawl Site when (A) MWTRs (solid bars) 

and (B) KDTRs (striped bars) were used during the 2000–2015 field seasons. The y-axis is 

presented on a common log scale.

1

10

100

1,000

10,000

100,000

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

log ( Absolute Abundance )

Estimated Wild

Estimated Hatchery

CWT Marked

(A) MWTR

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

1.E+05

1.E+06

1.E+07

1.E+08

1.E+09

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

log (Absolute Abundance )

(B) KDTR 109

108

107

106

105

104

103

102

101

100

100

105

104

103

102

101
55

Figure 32. Mean absolute abundance estimates and their 95% confidence intervals for juvenile 

winter-run Chinook Salmon at the Chipps Island Trawl Site during the 1995–2015 field seasons. 

Years with asterisks indicate that 1 or 2 months of that field season were not sampled, which 

may bias the low annual estimate.

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

Absolute Abundance

Estimated Wild

Estimated Hatchery

CWT Marked

Year
56

Figure 33. Mean absolute abundance estimates and their 95% confidence intervals for juvenile 

fall-, late fall-, and spring-run Chinook Salmon at the Sacramento Trawl Site when (A) MWTRs 

(solid bars) and (B) KDTRs (striped bars) were used during the 2000–2015 field seasons. The yaxis is presented on a common log scale.

1

10

100

1,000

10,000

100,000

1,000,000

10,000,000

100,000,000

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

log ( Absolute Abundance )

Estimated Wild Estimated Hatchery CWT Marked Unknown (A) MWTR

1

10

100

1,000

10,000

100,000

1,000,000

10,000,000

100,000,000

1,000,000,000

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

log (Absolute Abundance )

(B) KDTR

Year

100

101

102

103

1004

105

106

109

108

107

108

107

106

105

104

103

101

100

102
57

Figure 34. Mean absolute abundance estimates and their 95% confidence intervals for juvenile 

fall-, late fall-, and spring-run Chinook Salmon at the Mossdale Trawl Site during the 2004–2015

field seasons. The y-axis is presented on a common log scale. Juvenile Chinook Salmon captured 

at Mossdale are assumed to be fall-run only.

1

10

100

1,000

10,000

100,000

1,000,000

10,000,000

100,000,000

2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

log(Absolute Abundance)

Estimated Wild Estimated Hatchery CWT Marked Unknown

100

101

102

103

104

105

106

107

108

Year
58

Figure 35. Mean absolute abundance estimates and their 95% confidence intervals for juvenile 

fall-, late fall-, and spring-run Chinook Salmon at the Chipps Island Trawl Site (A) during April–

June during the 1978–2015 field seasons and (B) year-round during the 1995–2015 field seasons. 

Years with asterisks indicate that 1 or 2 months of that field season were not sampled, which 

may bias low the annual estimate. 

0

10,000,000

20,000,000

30,000,000

40,000,000

50,000,000

60,000,000

70,000,000

19781979198019811982198319841985198619871988198919901991199219931994199519961997

1998*

19992000200120022003200420052006

2007*

20082009201020112012201320142015

Absolute Abundance

Estimated Wild

Estimated Hatchery

CWT Marked

Unknown

0

5,000,000

10,000,000

15,000,000

20,000,000

25,000,000

30,000,000

35,000,000

40,000,000

45,000,000

50,000,000

Absolute Abundance

Estimated Wild

Estimated Hatchery

CWT Marked

Unkown

(A) April - June of 1978 - 2015

(B) 1995 - 2015 field seasons

Year
59

Fork Length Distributions

Unmarked juvenile Chinook varied considerably in size between seine regions and trawl sites 

during the 2014 and 2015 field seasons (Figures 36–40). At the Chipps trawl site and at 

Mossdale, juvenile Chinook tended to be larger in 2015 relative to 2014. However, the apparent 

size difference between years was not observed at Sacramento. The majority of salmon were 

identified as fry (FL<70 mm; Kjelson et al. 1982) and individuals were slightly larger (1–6 mm 

FL) within most seine regions and trawl sites during the 2015 field season. The FL distribution 

of unmarked juvenile Chinook captured during both the 2014 and 2015 field seasons ranged 

from 37–567 mm using the MWTR at the Chipps Island Trawl Site (Figure 36). At the Mossdale 

Trawl Site, the FL of fish captured by the KDTR ranged from 34–165 mm (Figure 36). Fish 

captured by the KDTR and MWTR at the Sacramento Trawl Site ranged from 25–143 mm and 

34–300 mm (FL), respectively (Figure 37). For beach seines, the range was 27‒142 mm in 2014

and 29‒189 mm during the 2015 field season (Figures 38–40). In contrast to beach seine catches, 

the majority of fishes captured by MWTR trawls in 2014 and 2015 were identified as smolts 

(FL≥70 mm; Kjelson et al. 1982). However, fishes captured within the KDTR at the Sacramento 

Trawl Site during both years were generally identified as fry. Our results are largely consistent 

with the observations made between the 2010 to 2013 field seasons (Speegle et al. 2013, Barnard 

et al. 2015) and indicate that fry- and smolt-sized individuals occupy both open water midchannel and near shore littoral habitats. 

Although our data and other investigations (e.g., Kjelson et al. 1982) imply that fry may prefer 

near-shore littoral habitat and that smolts may prefer to occupy open water mid-channel habitat 

during the day, these patterns could be confounded by the influence of sample bias from variable 

gear efficiencies (Bayley and Peterson 2001). For example, each trawl site was sampled using 

varying trawl nets (i.e., Chipps Island=MWTR, Mossdale=KDTR, and Sacramento=KDTR and 

MWTR), cod-end designs (i.e., Mossdale=live box, Chipps Island=mesh, and Sacramento=mesh 

and live box), and cod-end mesh sizes (i.e., Chipps Island MWTR=0.8 mm, Mossdale and 

Sacramento KDTR=0.46 mm, and Sacramento MWTR=0.3 mm), which can greatly affect the 

gear efficiency for different size classes of fish. Furthermore, the beach seine methods used by 

the DJFMP are thought to select for smaller individuals based on the fact that larger individuals 

are more likely able to avoid the gear during sampling. Thus, the DJFMP has completed, and 

will continue to perform studies on how gear efficiency varies among gear types, methods, and 

locations.
60 0 50 100 150 200

0

20

40

60

80

100

120

0 50 100 150 200

0

20

40

60

80

100

120

0 50 100 150 200

Catch count

0

20

40

60

80

100

120

140

Fork length (mm)

0 50 100 150 200

0

2

4

6

8

10

(A) Chipps Island Trawl Site

2014

n = 2285

(B) Chipps Island Trawl Site

2015

n = 1541

(C) Mossdale Trawl Site

2014

n = 1331

(D) Mossdale Trawl Site

2015

n = 73

Figure 36. Fork length distributions for juvenile Chinook Salmon captured in MWTRs at the 

Chipps Island Trawl Site and KDTRs at the Mossdale Trawl Site during the 2014 and 2015 field 

seasons.
61 0 50 100 150 200

0

20

40

60

80

100

120

0 50 100 150 200

0

2

4

6

8

10

0 50 100 150 200

Catch count

0

300

600

900

1200

1500

1800

2100

2400

Fork length (mm)

0 50 100 150 200

0

20

40

60

80

100

120

140

160

(A) Sacramento Trawl Site (MWTR)

2014

n = 1572

(B) Sacramento Trawl Site (MWTR)

2015

n = 72

(C) Sacramento Trawl Site (KDTR)

2014

n = 22,365

(D) Sacramento Trawl Site (KDTR)

2015

n = 607

Figure 37. Fork length distributions for unmarked juvenile Chinook Salmon captured in MWTRs 

and KDTRs at the Sacramento Trawl Site during the 2014 and 2015 field seasons.
62

0 20 40 60 80 100 120 140

0

200

400

600

800

1000

1200

1400

1600

0 20 40 60 80 100 120 140

0

20

40

60

80

100

0 20 40 60 80 100 120 140

Catch count

0

200

400

600

800

1000

1200

1400

Fork length (mm)

0 20 40 60 80 100 120 140

0

20

40

60

80

100

120

(A) Region 1

2014

n = 10,047

(B) Region 1

2015

n = 951

(C) Region 2

2014

n = 11,232

(D) Region 2

2015

n = 1173

Figure 38. Fork length distributions for unmarked juvenile Chinook Salmon captured in beach 

seines within the Lower Sacramento River (Region 1) and North Delta (Region 2) beach seine 

regions during the 2014 and 2015 field seasons.
63 0 20 40 60 80 100 120 140

0

10

20

30

40

0 20 40 60 80 100 120 140

0

1

2

3

4

5

0 20 40 60 80 100 120 140

Catch count

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Fork length (mm)

0 20 40 60 80 100 120 140

0

20

40

60

80

100

(A) Region 3

2014

n = 356

(B) Region 3

2015

n = 51

(C) Region 4

2014

n = 7

(D) Region 4

2015

n = 0

Figure 39. Fork length distributions for unmarked juvenile Chinook Salmon captured in beach 

seines within the Central Delta (Region 3) and South Delta (Region 4) beach seine regions 

during the 2014 and 2015 field seasons.
64

0 20 40 60 80 100 120 140

0

20

40

60

80

100

0 20 40 60 80 100 120 140

0

1

2

0 20 40 60 80 100 120 140

Catch count

0

20

40

60

80

100

Fork length (mm)

0 20 40 60 80 100 120 140

0

1

2

(A) Region 5

2014

n = 0

(B) Region 5

2015

n = 2

(C) Region 6

2014

n = 0

(D) Region 6

2015

n = 1

Figure 40. Fork length distributions for unmarked juvenile Chinook Salmon captured in beach 

seines within the Lower San Joaquin River (Region 5) and San Francisco and San Pablo Bay 

(Region 6) beach seine regions during the 2014 and 2015 field seasons.
65

MONITORING FOR DELTA CROSS CHANNEL OPERATIONS

Introduction

The DCC was constructed by the U.S. Bureau of Reclamation (USBR) in 1951 at Walnut Grove, 

California. The DCC was designed to facilitate the transfer of fresh water from the Sacramento 

River southwards through the channels of the Mokelumne River system towards the south Delta. 

Ultimately, water is diverted to the CVP and SWP pumps at Tracy which provide water for 

agricultural, municipal, and industrial uses within the Central Valley and southern California. 

The DCC gates enable USBR operators to increase the amount of Sacramento River water for

export. Historically, the DCC gates remained open, except during periods of high Sacramento 

River flow (20,000 to 25,000 cfs at Freeport) when risks of channel scouring or downstream 

flooding warranted their closure. The USBR currently operates the DCC gates in the open 

position to (1) improve the transfer of water from the Sacramento River to the CVP and SWP 

pumping facilities, (2) improve water quality in the southern Delta, and (3) to reduce the amount 

of Sacramento River flow needed to repel saltwater intrusion into the western Delta.

The operation of the DCC gates alters river flows throughout the Estuary and thereby influences 

the migration pathways and survival of emigrating juvenile Chinook (Kjelson and Brandes 1989; 

Kimmerer 2008; Newman and Brandes 2010; Perry et al. 2010). Juvenile salmon of all runs can 

be diverted into the central Delta when the DCC gates are open. In the central Delta, juvenile 

Chinook experience lower survival rates than if they stay on the mainstem Sacramento River 

(Brandes and McLain 2001; Newman and Brandes 2010). The lower survival in the central Delta 

may be due to water export, high water temperatures, predation and pollution (Moyle, 1994, 

Kimmerer 2008, Newman and Brandes, 2010). Because ESA-listed species, including springrun and winter-run Chinook, are affected by DCC operations, the state and federal fishery 

agencies have called for the closure of the DCC gates to reduce the entry of juvenile salmon into 

the central Delta. 

In 1978, the State Water Resources Control Board (SWRCB) instituted a decision (D-1485) to 

amend the water right permits of the CDWR and USBR for the SWP and the CVP facilities, 

respectively (SWRCB 1978). This decision mandated that in addition to reducing direct water 

diversion at the project pumps and releasing stored or natural water flows, DCC gate operations 

could be used to ensure adequate river flow for salinity control and to improve water quality for 

fish and wildlife in the estuarine ecosystem. The 1995 Water Quality Control Plan (WQCP) for 

the San Francisco Estuary (95-1) included specific guidelines for the operation of the DCC gates 

for the protection of threatened or endangered fish (SWRCB 1995), which were reaffirmed by 

the SWRCB in 1999 (D-1641) and the 2006 WQCP for the San Francisco Estuary (SWRCB 

2006). Recovery and Biological Opinions for the protection of juvenile winter-run and springrun Chinook were the basis for the salmon decision processes in controlling DCC gate operations 

for the protection of ESA-listed species (NMFS 2009b). 

Further modifications of DCC gate operations were instituted through the 2009 NMFS RPA, 

with 2011 amendments (NMFS 2011) that resulted from 2010 independent review panel report 

(Anderson et al. 2010). The current DCC operation plan (NMFS 2011, Action IV.1.2) mandates 

that the DCC gates be closed from October through November if fish species of management 
66

concern are present. Contingent upon water quality conditions, the DCC gates remain closed 

from December through January except during experiments approved by NMFS investigating 

fish migration patterns occurring from December 1 through December 14 (Table 2). The NMFS 

RPA mandates DCC closures from February 1 to May 20 for a maximum of 14 days between 

May 21 and June 15 if requested (NMFS 2011).

To facilitate coordination among the fishery resource agencies and project operators, a salmon 

decision process (refer to NMFS 2011 for the current process, Action IV.1.2) was drafted by 

NMFS to minimize the impact of the DCC on emigrating salmonids and Green Sturgeon 

Acipenser medirostris. Once the salmon decision process is triggered, depending on the 

magnitude of the catch and the water quality, recommendations are made to USBR through the 

Delta Operations for Salmonids and Sturgeon group (DOSS) to close the DCC gates (Table 2). 

The DOSS group is a technical advisory group made up of NMFS, USFWS, CDWR, CDFW and 

USBR (NMFS 2011, Action IV.5). The Knights Landing Catch Index (KLCI) and the 

Sacramento Catch Index (SCI) are the criteria upon which the first action is based for closing the 

DCC gates. The KLCI is calculated using catch data from the CDFW rotary screw trap located at 

Knights Landing. The SCI is generated from beach seine and trawl catch data collected by the 

DJFMP on the Sacramento River. 

The catch data are provided to the DOSS group through the Data Assessment Team (DAT) 

report. The SCI, used alone or in conjunction with the KLCI or increases in the average daily 

flow rates, may trigger various actions of the Salmon Decision Process (Table 2). In this section 

of the report, we will discuss how the relative abundance indices of unmarked winter-run sized 

or older juvenile Chinook occurring near Sacramento informed real-time DCC water operation 

decisions. 

Methods

The SCI was calculated using unmarked juvenile Chinook catch data collected either at the 

Sacramento Trawl Site or within the Sacramento Area Seine Region (Table 1; Figure 41). In 

general, the Sacramento Trawl Site was sampled three days per week from October through 

January during the 2014 and 2015 field seasons. In addition, eight beach seine sites located 

within the Sacramento Area Seine Region were sampled three days per week from October 

through December and one day per week in January (Tables A.23 and A.24). The increased 

sampling frequency of the beach seines during October through December was intended to better 

detect winter-run sized or older juvenile Chinook migrating near the DCC and inform real-time 

water diversion decisions (NMFS 2011). The frequency of sampling at the Sacramento Trawl 

Site did not increase during this period, but each year the Sacramento trawluses a KDTR in place 

of the MWTR between October and March to sample larger juvenile Chinook. The sampling 

methodologies and fish processing methods were the same as described earlier within the “LongTerm Monitoring” section. The race of all unmarked juvenile Chinook was categorized using the 

river LDC developed by Fisher (1992) and modified by Greene (1992).
67

Table 2. The Salmon Decision Process (NMFS 2011, RPA Action IV.1).

Time Trigger Action

Oct 1–Nov 30 Water quality criteria met, Knights Landing Catch Index 

(KLCI) and/or Sacramento Catch Index (SCI) > 3 and ≤ 5

Close Delta Cross Channel (DCC) gates for 3 days

 within 24 hours

Water quality criteria met, KLCI and/or SCI > 5 Close DCC gates until index < 3

Water quality criteria not met, KLCI and/or SCI > 3 DOSS elevates decision to NMFS & Water

 Operations Management Team (WOMT)

Dec 1–Dec 14

Water quality criteria are met

DCC gates closed, may be opened for Delta Action 

8

Water quality criteria not met, and KLCI and/or SCI < 3 Open DCC gates until water quality criteria met

Water quality criteria not met, and KLCI and/or SCI > 3 DOSS elevates decision to NMFS & WOMT

Dec 15–Jan 31 No triggers needed DCC gates closed

NMFS-approved experiments conducted DCC gates may be opened for 5 days

Feb 1–May 20 D-1641 mandatory gate closure DCC gates closed per water quality criteria

May 21–Jun 15 D-1641 gate operations criteria DCC gates closed for 14 days, if NMFS warrants
68

Figure 41. Sampling sites used to trigger Delta Cross Channel closures sampled during the 2014

and 2015 field season within the lower Sacramento River.
69

The SCI represents the number of winter-run size or larger juvenile Chinook captured within a 

day at the Sacramento Trawl Site or within the Sacramento Area Seine Region standardized to 

one day of effort and is calculated as:

SCIdG =

∑ CatchdG

SamplesdG

· SEG

(8)

where d indexes a sample day, G indexes gear type (i.e., seine or trawl), CatchdG represents the 

number of winter-run sized or larger juvenile Chinook Sample captured using gear type G during 

sample day d, SamplesdG represents the number of seine hauls or trawl tows completed during 

sample day d using gear type G, and SEG represents the standard number of samples completed 

using gear type G during a typical sample day (SEseine=8 and SEtrawl=10). All samples regardless 

of their condition (e.g., good, poor, etc.) were used for SCI estimates for each sample day.

Results and Discussion

Unmarked winter-run sized or larger juvenile Chinook were first detected within the Sacramento 

Area Beach Seine Region near the DCC water diversion gates during November 2014 for the 

2015 field season (Figure 42); none were observed in the 2014 field season (August 1, 2013 to 

July 31, 2014). The DJFMP Sacramento Catch Index did not trigger any DCC operations in the 

2014 field season. However, the Sacramento Trawl SCI or the Sacramento Beach Seine SCI 

exceeded the threshold of the salmon decision process on 8 sampling dates during the 2015 field 

season (Table 3; Figure 42). This either triggered or maintained the closure of the DCC gates in 

conjunction with the KLCI and water quality indices on 8 occasions (DCC operational logs and 

final DOSS notes; Barbara Byrne, NOAA, personal communication). 
70

Table 3. Salmon Decision Process trigger events (Sacramento Catch Index=SCI, Knights 

Landing Catch Index=KLCI) by sample day and gear type (beach seine or trawl) during the 2014

and 2015 field seasons.

Sample

date

SCI

(seine)

SCI

(trawl) Action IV.1.2

11/05/2014 2.00

11/07/2014

11/10/2014

11/12/2014

11/14/2014 2.29

11/17/2014

11/19/2014 1.14

11/20/2014 1.14

11/24/2014

11/26/2014

11/28/2014 2.00

12/01/2014 1.00

12/03/2014 4.57 2.00 SCI index triggered a recommendation to close gate for 7 days

12/05/2014 9.14 4.00 SCI indices triggered a recommendation to close gate for 7 days

12/08/2014 5.00 18.00 SCI indices triggered a recommendation to close gate for 7 days

12/09/2014 8.00 SCI index triggered a recommendation to close gate for 7 days

12/10/2014 4.57 SCI index triggered a recommendation to close gate for 7 days

12/12/2014 8.00 SCI index triggered a recommendation to close gate for 7 days

12/15/2014

12/16/2014 2.00

12/17/2014 5.71 SCI index triggered a recommendation to close gate for 7 days

12/19/2014 8.00 SCI index triggered a recommendation to close gate for 7 days

12/22/2014 7.00 2.00 SCI index triggered a recommendation to close gate for 7 days

12/24/2014 9.14 SCI index triggered a recommendation to close gate for 7 days

12/29/2014

12/31/2014

01/02/2015 1.14

01/05/2015

01/07/2015

01/09/2015

01/12/2015

01/14/2015

01/16/2015

01/20/2015

01/21/2015

01/23/2015

01/26/2015

01/27/2015 1.14
71

(A) 2014 field season

Oct Nov Dec Jan Feb Mar 

0

5

10

15

20

Seine SCI 

Trawl SCI 

Min trigger 

Max trigger 

(B) 2015 field season

Oct Nov Dec Jan Feb Mar 

Catch indeces

0

5

10

15

20

Figure 42. Sacramento Catch Index (SCI) estimates generated by the catch of winter-run size or 

larger juvenile Chinook Salmon in the Sacramento Trawl Site and within the Sacramento Area 

Beach Seine Region during the (A) 2014 and (B) 2015 field seasons and the minimum (blue 

dashed line) and maximum (red dashed line) SCI values required to trigger recommendations to 

close the Delta Cross Channel gates.

Month
72

LIBERTY ISLAND BEACH SEINE

Introduction

The Delta Juvenile Fish Monitoring Program (DJFMP) conducted field efforts at Liberty Island 

from March 2010 through February 2013 under the BREACH III agreement with the California 

Department of Fish and Wildlife, and this has since been integrated within DJFMP’s regular 

beach seine monitoring across the Delta. The DJFMP sampling at Liberty Island provides 

baseline data that can serve as a reference site for future restoration efforts at Liberty Island and 

other north Delta sites in conjunction with the EcoStore (formerly Bay Delta Conservation Plan)

and the Fish and Wildlife Service Operational Criteria and Plan Biological Opinion, respectively. 

The BREACH III study was intended to provide information regarding how abiotic and biotic 

factors control vegetation colonization and expansion and subsequent responses by higher 

trophic levels. Considering the uncertainty of biological responses to restoration efforts (Brown 

2003; Grimaldo et al. 2012), the sampling at Liberty Island provides important information 

regarding the design and implementation of restoration projects, particularly within an adaptive 

management framework. Therefore, it is critical to understand habitat factors that influence the 

abundance and occupancy of fishes over broad spatial and temporal scales. The objectives of the 

Liberty Island monitoring program were to (1) document the temporal and spatial distribution of 

native and non-native fishes and (2) evaluate the occupancy of Delta Smelt, Longfin Smelt, 

Sacramento Splittail, and juvenile Chinook Salmon.

Methods

We used beach seines (15 m × 1.2 m with 3 mm delta square mesh) to determine the distribution 

and relative abundance of juvenile and small adult fishes within shallow and unobstructed nearshore habitats of Liberty Island from October 2013 to September 2015. Beach seining and water 

quality methods followed those already established by the DJFMP and described in the 

“Methods” section. In general, we identified all fishes captured to species that were greater than 

25 mm in fork length (FL). We sampled a total of 21 fixed sites each month (10 - 11 sites per 

trip, two trips per month) distributed among four quadrants within Liberty Island (Figure 43). 

Ten sites were selected from locations previously sampled during a pilot study conducted from 

2002-2005 in the southern quadrants of Liberty Island (Hansen et al. 2005). In 2010, eleven new 

sites were selected in the northern quadrants of Liberty Island to maximize spatial coverage. 

Liberty Island was broken up into four quadrants based on habitat types and exposure. The 

southern quadrants of Liberty Island are tidally influenced however they remain inundated at low 

tide. The southeast quadrant of Liberty Island is susceptible to the effects of wind and wave 

erosion, whereas the southwest quadrant is more protected from those effects and tends to have 

more submerged aquatic vegetation (SAV). The northern quadrants of Liberty Island are heavily 

influenced by tide and are mostly characterized by exposed mudflats at low tide with a few 

channels and areas of inundation less than a meter. The northern quadrants have immense stands 

of emergent vegetation as well as large areas of SAV. Erosion due to wind and wave processes is 

limited to the southeast corner of the northeast quadrant of Liberty Island. 
73

Figure 43. Beach seine sites within sampling quadrants at Liberty Island from 2014 and 2015 

field seasons (Appendix B).
74

Results and Discussion

Water Quality

We collected 1,354 water quality samples during the 2014 and 2015 field seasons in the Liberty 

Island seine region: 342 water temperature, 336 conductivity, 336 dissolved oxygen, and 340 

turbidity samples. The intra-annual variability in water temperature was consistent among 

Liberty Island seine sites during the 2014 and 2015 field seasons and similar to the variability 

observed in the other seine regions and trawl sites (Figure 44). Water temperature ranged from 

4.4 to 27.7°C among Liberty Island seine sites during the 2014 field season and 5.4 to 26.0°C 

during the 2015 field season. 

 

We observed dissolved oxygen values ranging from 2.0 to 17.1 mg/L among Liberty Island seine 

sites during the 2014 field season and 6.5 to 14.2 mg/L among sites during the 2015 field season 

(Figure 45). In general, dissolved oxygen was slightly higher during the winter season and lower 

during the summer season for all Liberty Island seine sites during both field seasons. January 

2014 had the greatest range of dissolved oxygen levels. The most variation in the 2015 sampling 

season occurred in March. Similar to the other seine regions and trawl sites, upper and lower 

extremes tended to occur January/February through June. 

Turbidity samples ranged from 6.1 to 1,000 NTU and 0.4 to 417 NTU during the 2014 and 2015 

field seasons, respectively (Figure 46). With the exception of several anomalously high turbidity 

values in May of the 2014 field season, highest mean turbidity values occurred within the months 

of February, March and July, whereas for 2015 highest values were in December and February, 

with both years coinciding with peak flow events. Overall, temporal trends in turbidity were 

similar to those observed from other seine regions and trawl sites across the Delta. 

Conductivity ranged from 118.2 to 478 μS/cm and from 23.7 to 645 μS/cm during the 2014 and 

2015 field seasons, respectively (Figure 47). For the 2014 field season, highest mean 

conductivity occurred from the months of February to April, whereas in 2015 this was more 

protracted with similarly high values between the months of January to April. Overall, the range 

of conductivity values observed from the Liberty Island region was most similar to the ranges 

observed at the Sacramento and Mossdale trawl sites and the Lower Sacramento and North Delta 

seine regions. 
75

Water Temperature (oC)

0

5

10

15

20

25

30

35

2014 Field season

2015 Field season

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul 

Figure 44. Water temperature data collected by month during sampling at the Liberty Island 

seine region during the 2014 and 2015 field seasons. The boxes represent the 25th and 75th 

percentiles, the line within the box represents the median, the whiskers represent the 10th and 

90th percentiles, and points represent outliers.

Month
76

Dissolved oxygen (mg/L)

0

5

10

15

20

2014 Field season

2015 Field season

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul 

Figure 45. Dissolved oxygen data collected by month during sampling at the Liberty Island seine 

region during the 2014 and 2015 field seasons. The boxes represent the 25th and 75th 

percentiles, the line within the box represents the median, the whiskers represent the 10th and 

90th percentiles, and points represent outliers. 

Month
77

Turbidity (NTU)

0

200

400

600

800

1000 2014 Field season

2015 Field season

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul 

Figure 46. Turbidity data collected by month during sampling at the Liberty Island seine region 

during the 2014 and 2015 field seasons. The boxes represent the 25th and 75th percentiles, the 

line within the box represents the median, the whiskers represent the 10th and 90th percentiles, 

and points represent outliers. 

Month
78

Conductivity (μS/cm,log)

10

100

1000

2014 Field season

2015 Field season

 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul 

Figure 47. Conductivity data collected by month during sampling at the Liberty Island seine 

region during the 2014 and 2015 field seasons. The boxes represent the 25th and 75th 

percentiles, the line within the box represents the median, the whiskers represent the 10th and 

90th percentiles, and points represent outliers. The y-axis is presented on a common log scale. 

Month
79

Fish Assemblage

From the 2014 and 2015 field seasons a total of 28,896 fishes representing 29 species were 

collected by beach seine sampling within the Liberty Island seine region (this does not include 

marked or unidentified fish; Tables B.2 and B.3). Proportionally, from both years 58%

(n=16,697) of the fishes were observed during the 2014 field season. Species not native to the 

San Francisco Estuary accounted for approximately 97% (n=16,133) and 99.5% (n=12,138) of 

the total catch during the 2014 and 2015 field seasons, respectively. During the 2014 field 

season, the most abundant species were the Inland Silverside Menidia beryllina, juvenile 

Chinook Salmon Oncorhynchus tshawytscha, and Yellowfin Goby Acanthogobius flavimanus, 

comprising 96% of the total annual catch. For 2015, this changed slightly with dominant species 

being Inland Silverside, Threadfin Shad Dorosoma patenense, and Striped Bass Morone 

saxatilis, comprising 96% of the catch. 

Pelagic-nonnative fishes dominated catches in the Liberty Island region during both the 2014 and 

2015 field seasons (Figure 48). Within pelagic-nonnative fishes, the Inland Silverside was the 

most common species observed, comprising 91.7% (n=15,312) and 91.4% (n=11,144) of total 

catches during 2014 and 2015, respectively (Tables B.2 and B.3). The Inland Silverside was also 

the most common species observed at the Mossdale Trawl Site and in the Lower Sacramento 

River, North Delta, Central Delta, South Delta, and Lower San Joaquin River seine regions 

during the 2014 and 2015 field seasons (Tables A.3 and A.4). Within the Liberty Island region, 

the percentage of catch by month in both 2014 and 2015 was dominated by pelagic-nonnative 

fishes, which often exceeded 90% of the total. Some exceptions to this were in March 2014, 

when 38% of the catch was anadromous-pelagic-native (i.e. juvenile Chinook) and in May 2014 

when 34.6% of catch was composed of benthic-nonnative fishes (i.e. predominantly Yellowfin 

Goby). The mean yearly CPUE estimates for 2014 and 2015 indicated that pelagic-nonnative 

fishes increased in the Liberty Island region compared to previous sampling years (2003-2005 

and 2010-2013; Figure 49). The increased dominance of pelagic-nonnative fishes was also 

reflected in the mean yearly CPUE estimates at the Mossdale trawl site, especially in 2014. 

The mean yearly CPUE for juvenile Chinook in 2014 was more than an order of magnitude 

greater than in 2015 (Figures 48 and 49), and also greater than in every other year of sampling in 

the Liberty Island region (Figure 49). The higher CPUE of anadromous-pelagic-native fishes in 

2014 compared to 2015 is consistent with the trends exhibited in 2014 and 2015 from the other 

seine regions in the North Delta (Figure 20). Most of the difference was driven by CPUE in the 

months of February and March, also consistent with the trends observed in the other seine 

regions in the North Delta (Figure 19).
80

Figure 48. Mean monthly CPUE (bars) of juvenile fish assemblages captured within the Liberty 

Island seine region, and the estimated mean monthly Sacramento River discharge at Freeport 

(solid line) during the (A) 2014 and (B) 2015 field seasons.
81

Figure 49. Mean yearly CPUE (bars) of juvenile fish assemblages captured within the Liberty 

Island seine region, and the estimated mean yearly Sacramento River discharge at Freeport (solid 

line), during the 2003 through 2005 and 2010 through 2015 field seasons.

Juvenile Chinook Salmon

We captured 431 and 11 juvenile Chinook Salmon during the 2014 and 2015 field seasons, 

respectively (Tables B.2 and B.3). During the 2014 field season one individual was categorized 

as winter-run sized, 426 (99%) were fall-run sized, and four were spring-run sized (Table B.2)

based on the LDC. In 2015, all juvenile Chinook captured in the Liberty Island region were fallrun sized (n=11; Table B.3). No marked juvenile Chinook were collected during either 2014 or 

2015 (Table B.4). Since sampling began in 2003 in the Liberty Island seine region, a total of 13 

marked juvenile Chinook have been recovered (seven in 2003, one in 2004, one in 2010, three in 

2011, and one in 2012; Table B.4). 
82

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86

APPENDIX A

Table A.1. Sites sampled during the 2014 and 2015 field seasons categorized by gear (beach 

seine or trawl) and region. Station codes refer to body of water (first 2 letters; AR=American 

River, DS=Disappointment Slough, GS=Georgiana Slough, LP=Little Potato Slough, 

MK=Mokelumne River, MR=Middle River, MS=Mayberry Slough, OR=Old River, SA=San 

Francisco Bay, SB=Suisun Bay, SF=South Fork of Mokelumne River, SJ=San Joaquin River, 

SP=San Pablo Bay, SR=Sacramento River, SS=Steamboat Slough, TM=Three Mile Slough, 

WD=Werner Dredger Cut, or XC=Delta Cross Channel), river mile (3 digits), and location 

within site (last letter; N=north, S=south, W=west, E=east, or M=mid channel). For example, 

Colusa State Park is on the Sacramento River (SR) at river mile 144 on the west bank (W).

Site code Site name County

Coordinates (UTM) First 

year 

sampled 

annually

Zone Northing Easting

Region 1: Lower Sacramento River Seine

SR144W Colusa State Park Colusa 10 S 4341652 585032 1981

SR138E Ward's Landing Colusa 10 S 4338873 591787 1981

SR130E South Meridian Sutter 10 S 4329625 594819 1981

SR094E Reels Beach Sutter 10 S 4301235 610500 1981

SR090W Knights Landing Yolo 10 S 4295506 610842 1981

SR080Ea VeronaaSutter 10 S 4293731 620049 1981

SR071EaElkhornaSacramento 10 S 4281359 619626 1981

SR119E Tisdale Sutter 10S 4320172 601969 2012

Region 2: North Delta Seine

SR060Eb Discovery Parkb Sacramento 10 S 4273503 629820 1976

AM001Sb American Riverb Sacramento 10 S 4273377 630121 1976

SR049Eb Garcia Bendb Sacramento 10 S 4259863 627056 1976

SR043W Clarksburg Yolo 10 S 4249352 629186 1976

SS011N Steamboat Slough Sacramento 10 S 4240586 624600 1992

SR024E Koket Sacramento 10 S 4233475 626473 1976

SR017E Isleton Sacramento 10 S 4224781 621633 1976

SR014W Rio Vista Solano 10 S 4227355 617119 1976

SR012W Sandy Beach Solano 10 S 4222029 614333 2007

MS001N Sherman Island Sacramento 10 S 4212733 606513 1976

Region 3: Central Delta Seine

SJ005N Eddo's Sacramento 10 S 4212249 614110 1976

SJ001S Antioch Dunes Contra Costa 10 S 4208157 606855 1979

XC001N Delta Cross Channel Sacramento 10 S 4234115 630930 1976

GS010E Georgiana Slough Sacramento 10 S 4231900 628914 1976

MK004W B&W Marina Sacramento 10 S 4220909 624418 1979
87

Table A.1. Continued

Coordinates (UTM) First 

year 

sampled 

annually

Site code Site name County Zone Northing Easting

SF014E Wimpy's San Joaquin 10 S 4232068 632064 1976

TM001N Brannan Island Sacramento 10 S 4219577 615378 1976

DS002S King's Island San Joaquin 10 S 4213457 635248 1979

LP003E Terminous San Joaquin 10 S 4219075 631488 1979

Region 4: South Delta Seine

SJ051E Dos Reis San Joaquin 10 S 4188374 648601 1994

SJ041N Dad's Point San Joaquin 10 S 4202181 645287 1979

SJ032S Lost Isle San Joaquin 10 S 4206624 636393 1993

SJ026S Medford Island San Joaquin 10 S 4212589 630739 2002

OR023E Union Island San Joaquin 10 S 4187462 627498 1997

OR019E Old River San Joaquin 10 S 4193094 625167 1993

OR014W Cruiser Haven Contra Costa 10 S 4198087 626927 1993

OR003W Frank's Tract Contra Costa 10 S 4210312 624458 1993

MR010W Woodward Island San Joaquin 10 S 4198130 629336 1979

WD002W Veale Tract Contra Costa 10 S 4201793 622619 1993

Region 5: Lower San Joaquin River Seine

SJ083Wc N. of Tuolumne RivercStanislaus 10 S 4164462 660960 1994

SJ077E c Route 132cStanislaus 10 S 4167222 656395 1994

SJ074W cSturgeon BendcSan Joaquin 10 S 4170903 654784 1994

SJ068W c Durham SitecSan Joaquin 10 S 4173594 652327 1994

SJ063W c Big BeachcSan Joaquin 10 S 4176666 650093 1994

SJ058Wd Weatherbeed San Joaquin 10 S 4181923 649451 1994

SJ056Ed Mossdaled San Joaquin 10 S 4183536 649043 1994

SJ079Ee San Luis Refugee

Stanislaus 10 S 4166449 657914 2008

SJ076We N. of Route 132e

Stanislaus 10 S 4168198 656679 2008

SJ074Ae Sturgeon Bend 

Alternatee San Joaquin 10 S 4170228 654634 2008

Region 6: San Francisco and San Pablo Bay Seine

SA007E Berkeley Frontage Rd Alameda 10 S 4189562 561459 1997

SP001W China Camp Marin 10 S 4206179 546771 1997

SA009E Keller Beach Contra Costa 10 S 4196872 553964 1998

SP000W McNear's Beach Marin 10 S 4205405 547852 1997

SA008W Paradise Beach Marin 10 S 4194678 546872 1997

SP003E Point Pinole East Contra Costa 10 S 4206789 556219 1998
88

Table A.1. Continued.

Coordinates (UTM) First 

year 

sampled 

annually

Site code Site name County Zone Northing Easting

SA010W San Quentin Beach Marin 10 S 4199230 544068 1997

SA004W Tiburon Beach Marin 10 S 4193885 544413 1997

SA001M Treasure Island

San 

Francisco 10 S 4185026 555671 1997

Region 7: Sacramento Area Seine 

SR062E Sand Cove Sacramento 10 S 4273283 626860 1994

SR057E Miller Park Sacramento 10 S 4269001 629279 1994

SR055E Sherwood Harbor Sacramento 10 S 4265358 628190 1994

Trawls

SR055M Sacramento Sacramento 10 S 4265084 628299 1988

SJ054M Mossdale San Joaquin 10 S 4182898 649315 1996

SB055M,N,S Chipps Island Contra Costa 10 S 4211218 595531 1976

a

Site was included within both Region 1 and Region 7 from Oct 1 to Jan 31.

b

Site was included within both Region 2 and Region 7 from Oct 1 to Jan 31.

c

Site was sampled when San Joaquin River discharge was > 51m3/s during the 2000–2012 field 

seasons, and year-round during the 2013 field season.

d

Site was sampled throughout the field season during 2000–2013.

e

Site was sampled when San Joaquin River discharge was ≤ 51m3/s during the 2000–2012 field 

seasons.
89

Table A.2. Fish species, common names, and assemblage groups. Fish species are listed in phylogenetic order. 

Common name Genus Species Assemblage group

River Lamprey Lampetra ayresii Anadromous-benthic-native

Western Brook Lamprey Lampetra richardsoni Benthic-native

Pacific Lamprey Lampetra tridentatus Anadromous-benthic-native

Spiny Dogfish Squalus acanthias Benthic-native

Gray Smoothhound Mustelus californicus Benthic-native

Brown Smoothhound Mustelus henlei Benthic-native

Leopard Shark Triakis semifasciata Benthic-native

Pacific Electric Ray Torpedo californica Benthic-native

Thornback Ray Platyrhinoidis triseriata Benthic-native

Big Skate Raja binoculata Benthic-native

Bat Ray Myliobatis californica Benthic-native

Green Sturgeon Acipenser medirostris Anadromous-benthic-native

White Sturgeon Acipenser transmontanus Anadromous-benthic-native

American Eel Anguilla rostrata Benthic-nonnative

Northern Anchovy Engraulis mordax Pelagic-native

American Shad Alosa sapidissima Anadromous-pelagic-nonnative

Pacific Herring Clupea pallasii Pelagic-native

Threadfin Shad Dorosoma petenense Pelagic-nonnative

Pacific Sardine Sardinops sagax Pelagic-native

Goldfish Carassius auratus Pelagic-nonnative

Red Shiner Cyprinella lutrensis Pelagic-nonnative

Common Carp Cyprinus carpio Benthic-nonnative

Tui Chub Gila bicolor Pelagic-native

California Roach Hesperoleucus symmetricus Pelagic-native

Hitch Lavinia exilicauda Pelagic-native

Hardhead Mylopharodon conocephalus Pelagic-native

Golden Shiner Notemigonus crysoleucas Pelagic-nonnative
90

Table A.2. Continued.

Common name Genus Species Assemblage group

Sacramento Blackfish Orthodon microlepidotus Pelagic-native

Rosyface Shiner Notropis rubellus Pelagic-nonnative

Fathead Minnow Pimephales promelas Pelagic-nonnative

Sacramento Splittail Pogonichthys macrolepidotus Benthic-native

Sacramento Pikeminnow Ptychocheilus grandis Pelagic-native

Speckled Dace Rhinichthys osculus Pelagic-native

Sacramento Sucker Catostomus occidentalis Benthic-native

White Catfish Ameiurus catus Benthic-nonnative

Black Bullhead Ameiurus melas Benthic-nonnative

Yellow Bullhead Ameiurus natalis Benthic-nonnative

Brown Bullhead Ameiurus nebulosus Benthic-nonnative

Blue Catfish Ictalurus furcatus Benthic-nonnative

Channel Catfish Ictalurus punctatus Benthic-nonnative

Northern Pike Esox lucius Pelagic-nonnative

Whitebait Smelt Allosmerus elongatus Pelagic-native

Wakasagi Hypomesus nipponensis Pelagic-nonnative

Surf Smelt Hypomesus pretiosus Pelagic-native

Delta Smelt Hypomesus transpacificus Anadromous-pelagic-native

Night Smelt Spirinchus starksi Pelagic-native

Longfin Smelt Spirinchus thaleichthys Anadromous-pelagic-native

Pink Salmon Oncorhynchus gorbuscha Anadromous-pelagic-nonnative

Coho Salmon Oncorhynchus kisutch Anadromous-pelagic-native

Kokanee (lacustrine 

Sockeye Salmon)

Oncorhynchus nerka Pelagic-nonnative

Steelhead Oncorhynchus mykiss Anadromous-pelagic-native

Chinook Salmon Oncorhynchus tshawytscha Anadromous-pelagic-native

Brown Trout Salmo trutta Anadromous-pelagic-nonnative
91

Table A.2. Continued. Common name Genus Species Assemblage group

Plainfin Midshipman Porichthys notatus Benthic-native

Pacific Tomcod Microgadus proximus Pelagic-native

Striped Mullet Mugil cephalus Pelagic-native

Topsmelt Atherinops affinis Pelagic-native

Jacksmelt Atherinopsis californiensis Pelagic-native

Inland Silverside Menidia beryllina Pelagic-nonnative

Rainwater Killifish Lucania parva Pelagic-nonnative

Western Mosquitofish Gambusia affinis Pelagic-nonnative

Threespine Stickleback Gasterosteus aculeatus Anadromous-pelagic-native

Bay Pipefish Syngnathus leptorhynchus Pelagic-native

Brown Rockfish Sebastes auriculatus Benthic-native

Lingcod Ophiodon elongatus Benthic-native

Prickly Sculpin Cottus asper Benthic-native

Riffle Sculpin Cottus gulosus Benthic-native

Pacific Staghorn Sculpin Leptocottus armatus Benthic-native

Tidepool Sculpin Oligocottus maculosus Benthic-native

Saddleback Sculpin Oligocottus rimensis Benthic-native

Cabezon Scorpaenichthys marmoratus Benthic-native

White Bass Morone chrysops Pelagic-nonnative

Striped Bass Morone saxatilis Anadromous-pelagic-nonnative

Sacramento Perch Archoplites interruptus Pelagic-native

Green Sunfish Lepomis cyanellus Pelagic-nonnative

Pumpkinseed Lepomis gibbosus Pelagic-nonnative

Warmouth Lepomis gulosus Pelagic-nonnative

Bluegill Lepomis macrochirus Pelagic-nonnative

Redear Sunfish Lepomis microlophus Pelagic-nonnative

Smallmouth Bass Micropterus dolomieu Pelagic-nonnative

Spotted Bass Micropterus punctulatus Pelagic-nonnative
92

Table A.2. Continued.

Common name Genus Species Assemblage group

Redeye Bass Micropterus coosae Pelagic-nonnative

Largemouth Bass Micropterus salmoides Pelagic-nonnative

White Crappie Pomoxis annularis Pelagic-nonnative

Black Crappie Pomoxis nigromaculatus Pelagic-nonnative

Yellow Perch Perca flavescens Pelagic-nonnative

Bigscale Logperch Percina macrolepida Pelagic-nonnative

Pacific Pompano Peprilus simillimus Pelagic-native

White Croaker Genyonemus lineatus Pelagic-native

Barred Surfperch Amphistichus argenteus Pelagic-native

Calico Surfperch Amphistichus koelzi Pelagic-native

Redtail Surfperch Amphistichus rhodoterus Pelagic-native

Kelp Perch Brachyistius frenatus Pelagic-native

Shiner Perch Cymatogaster aggregata Pelagic-native

Black Perch Embiotoca jacksoni Pelagic-native

Striped Seaperch Embiotoca lateralis Pelagic-native

Spotfin Surfperch Hyperprosopon anale Pelagic-native

Walleye Surfperch Hyperprosopon argenteum Pelagic-native

Silver Surfperch Hyperprosopon ellipticum Pelagic-native

Tule Perch Hysterocarpus traskii Pelagic-native

Dwarf Surfperch Micrometrus minimus Pelagic-native

White Seaperch Phanerodon furcatus Pelagic-native

Rubberlip Seaperch Rhacochilus toxotes Pelagic-native

Pile Perch Rhacochilus vaccaPelagic-native

Penpoint Gunnel Apodichthys flavidus Benthic-native

Saddleback Gunnel Pholis ornata Benthic-native

Red Gunnel Pholis schultzi Benthic-native

Wolf-Eel Anarrhichthys ocellatus Benthic-native

Striped Kelpfish Gibbonsia metzi Pelagic-native
93

Table A.2. Continued.

Common name Genus Species Assemblage group

Crevice Kelpfish Gibbonsia montereyensis Pelagic-native

Giant Kelpfish Heterostichus rostratus Pelagic-native

Yellowfin Goby Acanthogobius flavimanus Benthic-nonnative

Arrow Goby Clevelandia ios Benthic-native

Tidewater Goby Eucyclogobius newberryi Benthic-native

Longjaw Mudsucker Gillichthys mirabilis Benthic-native

Cheekspot Goby Ilypnus gilberti Benthic-native

Bay Goby Lepidogobius lepidus Benthic-native

Shokihaze Goby Tridentiger barbatus Benthic-nonnative

Shimofuri Goby Tridentiger bifasciatus Benthic-nonnative

Chameleon Goby Tridentiger trigonocephalus Benthic-nonnative

Pacific Sanddab Citharichthys sordidus Benthic-native

Speckled Sanddab Citharichthys stigmaeus Benthic-native

Bigmouth Sole Hippoglossina stomata Benthic-nonnative

California Halibut Paralichthys californicus Benthic-native

Pacific Halibut Hippoglossus stenolepis Benthic-native

California Tonguefish Symphurus Atricauda Benthic-native

Butter Sole Isopsetta isolepis Benthic-native

Rock Sole Lepidopsetta bilineata Benthic-native

English Sole Parophrys vetulus Benthic-native

Starry Flounder Platichthys stellatus Benthic-native

Diamond Turbot Pleuronichthys guttulatus Benthic-native

Sand Sole Psettichthys melanostictus Benthic-native
94

Table A.3. Total of individuals observed in samples used to assess the fish assemblage structure during the 2014 field season. Counts 

are grouped by species and trawl site or seine region. Fish species are listed in phylogenetic order. Beach seine regions represent sites 

as assigned in Table A.1.

Fish species

Trawl site Beach seine region

Sacramento

Mossdale

Chipps 

Island

1 2 3 4 5 6

River Lamprey Lampetra ayresii 1 0 0 0 0 0 0 0 0

Pacific Lamprey Lampetra tridentatus 3 1 1 0 0 0 0 0 0

Lamprey unknown Lampetra spp. 1 0 0 2 1 0 0 0 0

Leopard Shark Triakis semifasciata 0 0 0 0 0 0 0 0 2

Thornback Ray Platyrhinoidis triseriata 0 0 0 0 0 0 0 0 2

Northern Anchovy Engraulis mordax 0 0 95 0 0 0 0 0 2780

American Shad Alosa sapidissima 73 1415 9149 1 25 11 3 0 2

Pacific Herring Clupea pallasii 0 0 152 0 0 0 0 0 143

Threadfin Shad Dorosoma petenense 351 10682 1747 792 584 2633 606 1031 1

Goldfish Carassius auratus 1 0 0 0 0 1 0 0 0

Red Shiner Cyprinella lutrensis 0 92 0 1226 41 1 67 41745 0

Common Carp Cyprinus carpio 3 5 1 30 0 4 1 5 0

Hitch Lavinia exilicauda 0 0 0 14 28 27 0 0 0

Hardhead Mylopharodon conocephalus 0 0 0 13 1 1 0 0 0

Golden Shiner Notemigonus crysoleucas 11 53 5 335 47 59 85 28 0

Fathead Minnow Pimephales promelas 2 0 0 1267 10 1 0 19 0

Sacramento Splittail Pogonichthys 

macrolepidotus 1 471 28 711 534 81 0 188 0

Sacramento Pikeminnow Ptychocheilus 

grandis 4 5 0 744 164 14 3 13 0

Sacramento Sucker Catostomus 

occidentalis 0 2 0 4814 2839 11 4 283 0
95

Table A.3. Continued.

Fish species

Trawl site Beach seine region

Sacramento

Mossdale

Chipps 

Island 

1 2 3 4 5 6

White Catfish Ameiurus catus 4 57 1 0 1 0 2 0 0

Black Bullhead Ameiurus melas 0 0 0 0 4 3 0 0 0

Brown Bullhead Ameiurus nebulosus 0 0 0 1 9 2 2 0 0

Channel Catfish Ictalurus punctatus 2 271 0 10 1 0 0 3 0

Wakasagi Hypomesus nipponensis 12 0 7 0 1 0 0 0 0

Surf Smelt Hypomesus pretiosus 0 0 5 0 0 0 0 0 0

Delta Smelt Hypomesus transpacificus 21 0 203 0 81 1 0 0 0

Longfin Smelt Spirinchus thaleichthys 0 0 111 0 0 0 0 0 0

Steelhead Oncorhynchus mykiss 273 11 80 18 11 2 0 0 0

 Unmarked Steelhead 9 6 14 0 0 0 0 0 0

 Marked Steelhead 264 0 66 18 11 2 0 0 0

 Acoustic Tag Steelhead 0 5 0 0 0 0 0 0 0

Juvenile Chinook Salmon Oncorhynchus 

tshawytscha 24369 1503 2810 10356 11238 363 7 0 0

 Unmarked winter-run 71 1 72 29 7 1 0 0 0

 Unmarked fall-run 23112 1040 886 10285 11171 344 7 0 0

 Unmarked spring-run 753 290 1311 39 53 11 0 0 0

 Unmarked late fall-run 0 0 5 1 1 0 0 0 0

 Unmarked not raced 0 157 0 0 0 0 0 0 0

 Marked w/ CWT 432 12 535 2 6 7 0 0 0

 Acoustic Tag 1 3 1 0 0 0 0 0 0

Plainfin Midshipman Porichthys notatus 0 0 0 0 0 0 0 0 1

Topsmelt Atherinops affinis 0 0 128 0 0 0 0 0 6168
96

Table A.3. Continued.

Fish species

Trawl site Beach seine region

Sacramento

Mossdale

Chipps 

Island 

1 2 3 4 5 6

Inland Silverside Menidia beryllina 4078 49612 6 6962 36497 15172 23229 34391 2

Rainwater Killifish Lucania parva 0 0 0 1 126 89 243 0 41

Western Mosquitofish Gambusia affinis 0 1 0 248 924 256 301 1347 0

Threespine Stickleback Gasterosteus 

aculeatus 0 0 9 0 361 12 0 0 26

Bay Pipefish Syngnathus leptorhynchus 0 0 0 0 0 0 0 0 101

Prickly Sculpin Cottus asper 0 0 0 2 25 65 47 2 0

Pacific Staghorn Sculpin Leptocottus armatus 0 0 3 0 46 92 0 0 206

Tidepool Sculpin Oligocottus maculosus 0 0 0 0 0 0 0 0 1

Cabezon Scorpaenichthys marmoratus 0 0 0 0 0 0 0 0 2

Striped Bass Morone saxatilis 1 679 409 0 57 133 68 34 4

Green Sunfish Lepomis cyanellus 0 0 0 2 1 0 1 0 0

Pumpkinseed Lepomis gibbosus 0 0 0 0 0 0 0 0 1

Warmouth Lepomis gulosus 0 0 0 0 0 0 2 0 0

Bluegill Lepomis macrochirus 9 1846 1 42 68 150 297 299 0

Redear Sunfish Lepomis microlophus 0 95 0 99 22 447 599 57 0

Smallmouth Bass Micropterus dolomieu 0 0 0 10 50 4 0 0 0

Spotted Bass Micropterus punctulatus 1 3 0 120 129 17 3 28 0

Largemouth Bass Micropterus salmoides 1 5 1 213 83 396 396 69 0

White Crappie Pomoxis annularis 0 2 1 2 0 0 0 0 0

Black Crappie Pomoxis nigromaculatus 2 1 0 78 5 1 0 6 0

Bigscale Logperch Percina macrolepida 0 0 0 312 48 84 39 3 0
97

Table A.3. Continued.

Fish species

Trawl site Beach seine region

Sacramento

Mossdale

Chipps 

Island

1 2 3 4 5 6

White Croaker Genyonemus lineatus 0 0 0 0 0 0 0 0 8

Barred Surfperch Amphistichus argenteus 0 0 0 0 0 0 0 0 132

Shiner Perch Cymatogaster aggregata 0 0 1 0 0 0 0 0 50

Black Perch Embiotoca jacksoni 0 0 0 0 0 0 0 0 3

Walleye Surfperch Hyperprosopon argenteum 0 0 0 0 0 0 0 0 75

Tule Perch Hysterocarpus traskii 5 1 7 20 183 148 7 0 0

Dwarf Surfperch Micrometrus minimus 0 0 0 0 0 0 0 0 179

Rubberlip Seaperch Rhacochilus toxotes 0 0 0 0 0 0 0 0 1

Crevice Kelpfish Gibbonsia montereyensis 0 0 0 0 0 0 0 0 1

Yellowfin Goby Acanthogobius flavimanus 0 2 3 0 150 119 3 0 10

Arrow Goby Clevelandia ios 0 0 0 0 0 0 0 0 41

Cheekspot Goby Llypnus gilberti 0 5 0 0 0 0 0 0 6

Bay Goby Lepidogobius Lepidus 0 0 0 0 0 0 0 0 1

Shokihaze Goby Tridentiger barbatus 0 0 0 0 0 0 0 0 1

Shimofuri Goby Tridentiger bifasciatus 0 11 8 0 55 93 73 0 22

California Halibut Paralichthys californicus 0 0 0 0 0 0 0 0 7

English Sole Parophrys vetulus 0 0 0 0 0 0 0 0 59

Starry Flounder Platichthys stellatus 0 0 1 0 0 0 0 0 0

Diamond Turbot Pleuronichthys guttulatus 0 0 0 0 0 0 0 0 14

Sand Sole Psettichthys melanostictus 0 0 0 0 0 0 0 0 7

California Tonguefish Symphurus atricauda 0 0 0 0 0 0 0 0 4

Unidentified fish 0 0 0 0 1 0 0 0 0
98

Table A.4. Total of individuals observed in samples used to assess the fish assemblage structure during the 2015 field season. Counts 

are grouped by species and trawl site or seine region. Fish species are listed in phylogenetic order. Beach seine regions represent sites 

as assigned in Table A.1.

Fish species

Trawl site Beach seine region

Sacramento

Mossdale

Chipps 

Island

1 2 3 4 5 6

River Lamprey Lampetra ayresii 6 0 0 0 0 0 0 0 0

Pacific Lamprey Lampetra tridentatus 102 4 0 0 0 0 0 0 0

Lamprey unknown Lampetra spp. 96 0 0 0 13 1 0 0 0

Northern Anchovy Engraulis mordax 0 0 341 0 0 0 0 0 1841

American Shad Alosa sapidissima 75 8136 7462 1 29 6 5 0 13

Pacific Herring Clupea pallasii 0 0 164 0 0 0 0 0 12

Threadfin Shad Dorosoma petenense 235 18116 1577 927 433 1481 3186 500 0

Goldfish Carassius auratus 1 0 0 4 0 0 0 0 0

Red Shiner Cyprinella lutrensis 0 16 0 1230 39 4 58 12139 0

Common Carp Cyprinus carpio 11 0 0 9 0 0 0 2 0

California Roach Hesperoleucus symmetricus 0 0 0 1 0 0 0 0 0

Hitch Lavinia exilicauda 0 0 1 10 7 43 0 0 0

Hardhead Mylopharodon conocephalus 0 0 0 26 1 0 0 0 0

Golden Shiner Notemigonus crysoleucas 1 12 1 38 29 158 117 42 0

Fathead Minnow Pimephales promelas 0 0 0 210 8 0 0 0 0

Sacramento Splittail Pogonichthys 

macrolepidotus 7 196 246 595 691 75 0 13 0

Sacramento Pikeminnow Ptychocheilus 

grandis 83 0 2 993 407 175 34 0 0

Sacramento Sucker Catostomus occidentalis 1 1 0 7768 918 5 0 92 0

White Catfish Ameiurus catus 3 57 0 0 3 0 0 0 0
99

Table A.4. Continued.

Fish species

Trawl site Beach seine region

Sacramento

Mossdale

Chipps 

Island

1 2 3 4 5 6

Black Bullhead Ameiurus melus 0 0 0 0 2 1 0 0 0

Brown Bullhead Ameiurus nebulosus 1 1 0 0 0 0 0 0 0

Channel Catfish Ictalurus punctatus 0 55 0 1 0 0 0 0 0

Wakasagi Hypomesus nipponensis 2 0 0 1 1 0 0 0 0

Delta Smelt Hypomesus transpacificus 0 0 12 0 39 0 0 0 0

Longfin Smelt Spirinchus thaleichthys 0 0 245 0 1 0 0 0 0

Steelhead Oncorhynchus mykiss 11 25 81 1 4 1 0 0 0

 Unmarked Steelhead 1 17 3 0 0 0 0 0 0

 Marked Steelhead 10 0 78 1 4 1 0 0 0

 Acoustic Tag 0 8 0 0 0 0 0 0 0

Juvenile Chinook Salmon Oncorhynchus 

tshawytscha 844 78 2175 1057 1188 53 0 2 2

 Unmarked winter-run 20 0 35 42 19 1 0 0 0

 Unmarked fall-run 601 5 371 768 894 40 0 2 0

 Unmarked spring-run 66 68 1108 237 257 10 0 0 1

 Unmarked late fall-run 5 0 22 3 3 0 0 0 0

 Spray dyed 0 3 0 0 0 0 0 0 0

 Marked w/ CWT 152 2 639 7 15 2 0 0 1

Plainfin Midshipman Porichthys notatus 0 0 1 0 0 0 0 0 0

Striped Mullet Mugil cephalus 0 0 0 0 0 1 0 0 5

Topsmelt Atherinops affinis 0 0 12 0 0 0 0 0 4204

Jacksmelt Atherinopsis californiensis 0 0 17 0 0 0 0 0 11

Inland Silverside Menidia beryllina 320 4467 0 8076 30232 9800 33960 11566 55
100

Table A.4. Continued.

Fish species

Trawl site Beach seine region

Sacramento

Mossdale

Chipps 

Island

1 2 3 4 5 6

Rainwater Killifish Lucania parva 0 0 0 0 439 53 118 0 20

Western Mosquitofish Gambusia affinis 1 0 0 306 508 89 125 271 0

Threespine Stickleback Gasterosteus 

aculeatus 3 0 7 10 17 5 0 0 8

Bay Pipefish Syngnathus leptorhynchus 0 0 0 0 0 0 0 0 49

Prickly Sculpin Cottus asper 0 0 0 3 7 9 6 0 0

Pacific Staghorn Sculpin Leptocottus armatus 0 0 0 0 0 3 0 0 48

Cabezon Scorpaenichthys marmoratus 0 0 0 0 0 0 0 0 1

Striped Bass Morone saxatilis 5 887 906 0 128 85 81 37 4

Green Sunfish Lepomis cyanellus 0 1 0 3 1 0 1 0 0

Warmouth Lepomis gulosus 1 0 0 0 0 1 0 0 0

Bluegill Lepomis macrochirus 32 1270 12 63 49 245 370 806 0

Redear Sunfish Lepomis microlophus 11 223 1 21 52 613 717 145 0

Smallmouth Bass Micropterus dolomieu 0 1 0 49 27 5 0 3 0

Redeye Bass Micropterus coosae 0 1 0 0 0 0 0 0 0

Spotted Bass Micropterus punctulatus 0 8 0 244 82 16 17 21 0

Largemouth Bass Micropterus salmoides 10 17 3 139 73 294 206 79 0

White Crappie Pomoxis annularis 0 0 0 8 0 0 0 0 0

Black Crappie Pomoxis nigromaculatus 3 3 1 6 2 0 1 2 0

Bigscale Logperch Percina macrolepida 0 1 0 291 13 64 16 0 0

White Croaker Genyonemus lineatus 0 0 0 0 0 0 0 0 1

Barred Surfperch Amphistichus argenteus 0 0 0 0 0 0 0 0 118

Calico Surfperch Amphistichus koelzi 0 0 0 0 0 0 0 0 1
101

Table A.4. Continued.

Fish species

Trawl site Beach seine region

Sacrament

o

Mossdale

Chipps 

Island

1 2 3 4 5 6

Shiner Perch Cymatogaster aggregata 0 0 0 0 0 0 0 0 8

Black Perch Embiotoca jacksoni 0 0 0 0 0 0 0 0 3

Walleye Surfperch Hyperprosopon argenteum 0 0 0 0 0 0 0 0 144

Tule Perch Hysterocarpus traskii 11 0 4 22 176 154 10 0 0

Dwarf Surfperch Micrometrus minimus 0 0 0 0 0 0 0 0 63

White Seaperch Phanerodon furcatus 0 0 0 0 0 0 0 0 1

Crevice Kelpfish Gibbonsia montereyensis 0 0 0 0 0 0 0 0 2

English Sole Parophrys vetulus 0 0 0 0 0 0 0 0 4

Starry Flounder Platichthys stellatus 0 0 6 0 9 10 0 0 6

Diamond Turbot Pleuronichthys guttulatus 0 0 0 0 0 0 0 0 11

Sand Sole Psettichthys melanostictus 0 0 0 0 0 0 0 0 7

California Tonguefish Symphurus atricauda 0 0 1 0 0 0 0 0 0

Unidentified fish 0 5 0 0 0 0 0 0 1
102

Table A.5. Number of sample days and average number, standard deviation, and range of trawls 

per sample day for trawl sites within sample weeks during the 2014 field season.

Chipps Island (SB018M,N,S) Mossdale (SJ054M) Sacramento (SR055M)

Sample 

week

Sample 

days

Average 

trawls per 

sample day 

(SD)

Range Sample 

days

Average 

trawls per 

sample day 

(SD)

Range Sample 

days

Average 

trawls per 

sample day 

(SD)

Range

7/28/2013 1 10 (0) 10 1 10 (0) 10 1 10 (0) 10

8/4/2013 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

8/11/2013 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

8/18/2013 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

8/25/2013 3 10 (0) 10 3 10 (0) 10 3 8.67 (2.31) 6-10

9/1/2013 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

9/8/2013 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

9/15/2013 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

9/22/2013 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

9/29/2013 1 10 (0) 10 1 10 (0) 10 1 10 (0) 10

10/13/2013 1 10 (0) 10 1 10 (0) 10 1 10 (0) 10

10/20/2013 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

10/27/2013 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

11/3/2013 3 10 (0) 10 3 7 (5.20) 1-10 3 10 (0) 10

11/10/2013 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

11/17/2013 2 10 (0) 10 3 10 (0) 10 3 10 (0) 10

11/24/2013 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

12/1/2013 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

12/8/2013 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

12/15/2013 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

12/22/2013 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

12/29/2013 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

1/5/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

1/12/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

1/19/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

1/26/2014 3 7.33 (4.62) 2-10 3 10 (0) 10 3 10 (0) 10

2/2/2014 3 10 (0) 10 3 9 (1.73) 7-10 6 10 (0) 10

2/9/2014 3 10 (0) 10 2 10 (0) 10 7 10 (0) 10

2/16/2014 3 10 (0) 10 2 10 (0) 10 7 10 (0) 10

2/23/2014 3 10 (0) 10 3 10 (0) 10 5 10 (0) 10

3/2/2014 3 9.67 (0.58) 9-10 3 10 (0) 10 3 10 (0) 10

3/9/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

3/16/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

3/23/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10
103

Table A.5. Continued.

Chipps Island (SB018M,N,S) Mossdale (SJ054M) Sacramento (SR055M)

Sample 

week

Sample 

days

Average 

trawls per 

sample day 

(SD)

Range Sample 

days

Average 

trawls per 

sample day 

(SD)

Range Sample 

days

Average 

trawls per 

sample day 

(SD)

Range

3/30/2014 3 10 (0) 10 5 10 (0) 10 3 10 (0) 10

4/6/2014 3 10 (0) 10 5 10.8 (1.79) 10-14 3 10 (0) 10

4/13/2014 3 10 (0) 10 5 10 (0) 10 3 10 (0) 10

4/20/2014 3 10 (0) 10 5 10 (0) 10 3 10 (0) 10

4/27/2014 3 10 (0) 10 5 10 (0) 10 3 10 (0) 10

5/4/2014 2 10 (0) 10 5 10 (0) 10 2 10 (0) 10

5/11/2014 2 10 (0) 10 5 10 (0) 10 2 10 (0) 10

5/18/2014 2 10 (0) 10 5 10 (0) 10 2 10 (0) 10

5/25/2014 2 10 (0) 10 4 10 (0) 10 2 10 (0) 10

6/1/2014 2 10 (0) 10 3 10 (0) 10 2 10 (0) 10

6/8/2014 2 10 (0) 10 3 10 (0) 10 2 10 (0) 10

6/15/2014 2 10 (0) 10 3 10 (0) 10 2 10 (0) 10

6/22/2014 2 10 (0) 10 3 10 (0) 10 2 10 (0) 10

6/29/2014 3 9 (1.73) 7-10 3 10 (0) 10 3 10 (0) 10

7/6/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

7/13/2014 3 9.33 (1.15) 8-10 3 10 (0) 10 3 10 (0) 10

7/20/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

7/27/2014 2 10 (0) 10 2 10.5 (0.71) 10-11 2 10 (0) 10
104

Table A.6. Number of sample days and average number, standard deviation, and range of trawls 

per sample day for trawl sites within sample weeks during the 2015 field season.

Chipps Island (SB018M,N,S) Mossdale (SJ054M) Sacramento (SR055M)

Sample 

week

Sample 

days

Average 

trawls per 

sample day 

(SD)

Range Sample 

days

Average 

trawls per 

sample day 

(SD)

Range Sample 

days

Average 

trawls per 

sample day 

(SD)

Range

7/27/2014 1 10 (0) 10 1 10 (0) 10 1 10 (0) 10

8/3/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

8/10/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

8/17/2014 3 10 (0) 10 3 10 (0) 10 3 10.33 (0.58) 10-11

8/24/2014 3 10 (0) 10 2 10 (0) 10 3 10 (0) 10

8/31/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

9/7/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

9/14/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

9/21/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

9/28/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

10/5/2014 3 10 (0) 10 3 10 (0) 10 3 9 (1.73) 7-10

10/12/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

10/19/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

10/26/2014 3 10 (0) 10 2 10 (0) 10 3 10 (0) 10

11/2/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

11/9/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

11/16/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

11/23/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

11/30/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

12/7/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

12/14/2014 2 10 (0) 10 3 10 (0) 10 3 10 (0) 10

12/21/2014 2 10 (0) 10 2 10 (0) 10 2 10 (0) 10

12/28/2014 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

1/4/2015 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

1/11/2015 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

1/18/2015 3 7 (5.20) 1-10 3 10 (0) 10 3 10 (0) 10

1/25/2015 3 10 (0) 10 3 9.33 (1.15) 8-10 3 10 (0) 10

2/1/2015 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

2/8/2015 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

2/15/2015 3 10 (0) 10 2 10 (0) 10 3 10 (0) 10

2/22/2015 3 8.33 (2.89) 5-10 3 10 (0) 10 3 10 (0) 10

3/1/2015 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

3/8/2015 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

3/15/2015 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

3/22/2015 3 8.67 (2.31) 6-10 3 10 (0) 10 3 10 (0) 10
105

Table A.6. Continued.

Chipps Island (SB018M,N,S) Mossdale (SJ054M) Sacramento (SR055M)

Sample 

week

Sample 

days

Average 

trawls per 

sample day 

(SD)

Range Sample 

days

Average 

trawls per 

sample day 

(SD)

Range Sample 

days

Average 

trawls per 

sample day 

(SD)

Range

3/29/2015 3 10 (0) 10 5 10 (0) 10 3 10 (0) 10

4/5/2015 3 10 (0) 10 5 10 (0) 10 3 10 (0) 10

4/12/2015 3 10 (0) 10 5 10 (0) 10 3 10 (0) 10

4/19/2015 3 10 (0) 10 5 10 (0) 10 3 10 (0) 10

4/26/2015 3 10 (0) 10 5 10 (0) 10 4 9.75 (0.5) 9-10

5/3/2015 2 10 (0) 10 5 10 (0) 10 2 10 (0) 10

5/10/2015 2 10 (0) 10 4 10 (0) 10 6 10 (0) 10

5/17/2015 2 10 (0) 10 4 10 (0) 10 2 10 (0) 10

5/24/2015 2 10 (0) 10 4 10 (0) 10 2 10 (0) 10

5/31/2015 2 10 (0) 10 3 10 (0) 10 2 10 (0) 10

6/7/2015 2 10 (0) 10 3 10 (0) 10 2 10 (0) 10

6/14/2015 2 10 (0) 10 3 10 (0) 10 2 10 (0) 10

6/21/2015 2 10 (0) 10 3 10 (0) 10 2 9 (1.41) 8-10

6/28/2015 3 10 (0) 10 3 10 (0) 10 2 10 (0) 10

7/5/2015 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

7/12/2015 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

7/19/2015 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10

7/26/2015 3 10 (0) 10 3 10 (0) 10 3 10 (0) 10
106

Table A.7. Beach seine sites where fish samples were collected at least once within a sample 

week in the Lower Sacramento River Seine Region during the 2014 field season.

Sample Station code

week SR071E SR080E SR090W SR094E SR119E SR130E SR138E SR144W

7/28/2013 X X X X X X

8/4/2013 X X X X X X X X

8/11/2013 X X X X X X X X

8/18/2013 X X X X X X X

8/25/2013 X X X X X X X

9/1/2013 X X X X X X

9/8/2013 X X X X X X

9/15/2013 X X X X X X X

9/22/2013 X X X X X X X

10/13/2013 X X

10/20/2013 X X X X X X X

10/27/2013 X X X X X X X

11/3/2013 X X X X X X X

11/10/2013 X X X X X X X

11/17/2013 X X X X X

11/24/2013 X X X X X

12/1/2013 X X X X X

12/8/2013 X X X X X X

12/15/2013 X X X X X

12/22/2013 X X X X X

12/29/2013 X X X X X X

1/5/2014 X X X X X X

1/12/2014 X X X X X

1/19/2014 X X X X X

1/26/2014 X X X

2/2/2014 X X X X

2/9/2014 X X X X X X

2/16/2014 X X X X X X X

2/23/2014 X X X X X X

3/2/2014 X X X X X X

3/9/2014 X X X X X X

3/16/2014 X X X X X

3/23/2014 X X X X X X

3/30/2014 X X X X X X

4/6/2014 X X X X X X

4/13/2014 X X X X X X

4/20/2014 X X X X

4/27/2014 X X X X
107

Table A.7. Continued.

Sample Station code

week SR071E SR080E SR090W SR094E SR119E SR130E SR138E SR144W

5/4/2014 X X X X

5/11/2014 X X X X X

5/18/2014 X X X X

5/25/2014 X X X X X

6/1/2014 X X X X X X

6/8/2014 X X X X X

6/15/2014 X X X X X

6/22/2014 X X X X X

6/29/2014 X X X X X

7/6/2014 X X X X X X X

7/13/2014 X X X X X X

7/20/2014 X X X X X X

7/27/2014 X X X X X X
108

Table A.8. Beach seine sites where fish samples were collected at least once within a sample 

week in the Lower Sacramento River Seine Region during the 2015 field season.

Sample Station code

week SR071E SR080E SR090W SR094E SR119E SR130E SR138E SR144W

8/3/2014 X X X X X X

8/10/2014 X X X X X X

8/17/2014 X X X X X X

8/24/2014 X X X X X

8/31/2014 X X X X X X

9/7/2014 X X X X X

9/14/2014 X X X X X

9/21/2014 X X X X X

9/28/2014 X X X X X X

10/5/2014 X X X X

10/12/2014 X X X X X X

10/19/2014 X X X X X X

10/26/2014 X X X X X

11/2/2014 X X X X X X

11/9/2014 X X X X X X

11/16/2014 X X X X X

11/23/2014 X X X X X X X

11/30/2014 X X X X X X

12/7/2014 X X

12/14/2014 X X X X X

12/21/2014 X X X

12/28/2014 X X X

1/4/2015 X X X X

1/11/2015 X X X X X

1/18/2015 X X X X X X

1/25/2015 X X X X

2/1/2015 X X X X X

2/8/2015 X X X X

2/15/2015 X X X X

2/22/2015 X X X X X

3/1/2015 X X X X X X

3/8/2015 X X X X

3/15/2015 X X X X

3/22/2015 X X X X X

3/29/2015 X X X X X X

4/5/2015 X X X X

4/12/2015 X X X X X

4/19/2015 X X X X X X
109

Table A.8. Continued.

Sample Station code

week SR071E SR080E SR090W SR094E SR119E SR130E SR138E SR144W

4/26/2015 X X X X X X

5/3/2015 X X X X X X

5/10/2015 X X X X X

5/17/2015 X X X X X

5/24/2015 X X X X

5/31/2015 X X X X X

6/7/2015 X X X

6/14/2015 X X X X X X

6/21/2015 X X X X X

6/28/2015 X X X X X X

7/5/2015 X X X X

7/12/2015 X X X X X X

7/19/2015 X X X X X

7/26/2015 X X X X
110

Table A.9. Beach seine sites where fish samples were collected at least once within a sample 

week in the North Delta Seine Region during the 2014 field season.

Sample Station code

week AM001S MS001A MS001N SR012W SR014W SR017E SR024E SR043W SR049E SR060E SS011N

8/4/2013 X X X X X X X X X

8/11/2013 X X X X X X X X X X

8/18/2013 X X X X X X X X X

8/25/2013 X X X X X X X X X

9/1/2013 X X X X X X X X X

9/8/2013 X X X X X X X X X X

9/15/2013 X X X X X X X X X X

9/22/2013 X X X X X X X X X X

10/13/2013 X X X

10/20/2013 X X X X X X X X X

10/27/2013 X X X X X X X X X

11/3/2013 X X X X X X X X X

11/10/2013 X X X X X X X X X X

11/17/2013 X X X X X X X X X X

11/24/2013 X X X X X X X X X

12/1/2013 X X X X X X X X X

12/8/2013 X X X X X X X X X X

12/15/2013 X X X X X X X X X

12/22/2013 X X X X X X X X X X

12/29/2013 X X X X X X X X X X

1/5/2014 X X X X X X X X X X

1/12/2014 X X X X X X X X X X

1/19/2014 X X X X X X X X X X

1/26/2014 X X X X X X X

2/2/2014 X X X X X X X X X X

2/9/2014 X X X X X X X X X X

2/16/2014 X X X X X X X X X

2/23/2014 X X X X X X X X X X

3/2/2014 X X X X X X X X X

3/9/2014 X X X X X X X X X

3/16/2014 X X X X X X X X X X

3/23/2014 X X X X X X X X X

3/30/2014 X X X X X X X

4/6/2014 X X X X X X X X X

4/13/2014 X X X X X X X X X

4/20/2014 X X X X X X X X X X

4/27/2014 X X X X X X X X X

5/4/2014 X X X X X X X X X X

5/11/2014 X X X X X X X

5/18/2014 X X X X X X X X X X

5/25/2014 X X X X X X X X

6/1/2014 X X X X X X X X

6/8/2014 X X X X X X X

6/15/2014 X X X X X X X X X X

6/22/2014 X X X X X X X X

6/29/2014 X X X X X X X X X X

7/6/2014 X X X X X X X X X

7/13/2014 X X X X X X X X X X

7/20/2014 X X X X X X X X X

7/27/2014 X
111

Table A.10. Beach seine sites where fish samples were collected at least once within a sample 

week in the North Delta Seine Region during the 2015 field season.

Sample Station code

week AM001S MS001A MS001N SR012W SR014W SR017E SR024E SR043W SR049E SR060E SS011N

7/27/2014 X X X X X X

8/3/2014 X X X X X X X X X

8/10/2014 X X X X X X X X

8/17/2014 X X X X X X X X

8/24/2014 X X X X X X X X X

8/31/2014 X X X X X X X X X

9/7/2014 X X X X X X X X X

9/14/2014 X X X X X X X X X X

9/21/2014 X X X X X X

9/28/2014 X X X X X X X X X

10/5/2014 X X X X X X X X X X

10/12/2014 X X X X X X X

10/19/2014 X X X X X X X X

10/26/2014 X X X X X X X X

11/2/2014 X X X X X X X

11/9/2014 X X X X X X X

11/16/2014 X X X X X X X X X

11/23/2014 X X X X X X X X X

11/30/2014 X X X X X X X X X

12/7/2014 X X X X X X X

12/14/2014 X X X X X

12/21/2014 X X X X X X

12/28/2014 X X X X X X

1/4/2015 X X X X X X X X

1/11/2015 X X X X X X

1/18/2015 X X X X X X X X X

1/25/2015 X X X X X X X

2/1/2015 X X X X X X X X X

2/8/2015 X X X X X X X X

2/15/2015 X X X X X X X

2/22/2015 X X X X X X X X

3/1/2015 X X X X X X X X X

3/8/2015 X X X X X X X X

3/15/2015 X X X X X X X X X

3/22/2015 X X X X X X X X

3/29/2015 X X X X X X X X

4/5/2015 X X X X X X X X X

4/12/2015 X X X X X X X X

4/19/2015 X X X X X X X X

4/26/2015 X X X X X X X X X X

5/3/2015 X X X X X X X

5/10/2015 X X X X X X X X X X

5/17/2015 X X X X X X

5/24/2015 X X X X X X X X

5/31/2015 X X X X X X

6/7/2015 X X X X X X X X

6/14/2015 X X X X X X X X

6/21/2015 X X X X X X X X X

6/28/2015 X X X X X X X

7/5/2015 X X X X X X X X X

7/12/2015 X X X X X X X X

7/19/2015 X X X X X X X

7/26/2015 X X X X X X X
112

Table A.11. Beach seine sites where fish samples were collected at least once within a sample 

week in the Central Delta Seine Region during the 2014 field season.

Sample Station code

week DS002S GS010E LP003E MK004W SF014E SJ001S SJ005N TM001N XC001N

8/4/2013 X X X X X X X

8/11/2013 X X X X X X X X

8/18/2013 X X X X X X X

8/25/2013 X X X X X X X X

9/1/2013 X X X X X X X X X

9/8/2013 X X X X X X X

9/15/2013 X X X X X X X X

9/22/2013 X X X X X X X

10/20/2013 X X X X X X X

10/27/2013 X X X X X X X

11/3/2013 X X X X X X X

11/10/2013 X X X X X X X

11/17/2013 X X X X X X X X

11/24/2013 X X X X X X X X

12/1/2013 X X X X X X

12/8/2013 X X X X X X X

12/15/2013 X X X X X X X

12/22/2013 X X X X X X X

12/29/2013 X X X X X X X X X

1/5/2014 X X X X X X X

1/12/2014 X X X X X X X X X

1/19/2014 X X X X X X X X

1/26/2014 X X X

2/2/2014 X X X X X X

2/9/2014 X X X X X X X X

2/16/2014 X X X X X X X X X

2/23/2014 X X X X X X X

3/2/2014 X X X X X X X

3/9/2014 X X X X X X X X X

3/16/2014 X X X X X X X X

3/23/2014 X X X X X X

3/30/2014 X X X X X X X X X

4/6/2014 X X X X X X X X X

4/13/2014 X X X X X X X X

4/20/2014 X X X X

4/27/2014 X X X X X X X

5/4/2014 X X X X X X X X X

5/11/2014 X X X X X X X X

5/18/2014 X X X X X X X

5/25/2014 X X X X X X

6/1/2014 X X X X X X X

6/8/2014 X X X X

6/15/2014 X X X X X X

6/22/2014 X X X X X X X

6/29/2014 X X X X X X X

7/6/2014 X X X X X X X X

7/13/2014 X X X X X X X

7/20/2014 X X X X X X X X

7/27/2014 X X X X
113

Table A.12. Beach seine sites where fish samples were collected at least once within a sample 

week in the Central Delta Seine Region during the 2015 field season.

Sample Station code

week DS002S GS010E LP003E MK004W SF014E SJ001S SJ005N TM001N XC001N

7/27/2014 X X

8/3/2014 X X X X X X X X

8/10/2014 X X X X X X

8/17/2014 X X X X X X X

8/24/2014 X X X X X X

8/31/2014 X X X X X X X X

9/7/2014 X X X X X X

9/14/2014 X X X X X

9/21/2014 X X X X X X X

9/28/2014 X X X X X

10/5/2014 X X X X X

10/12/2014 X X X X X

10/19/2014 X X X X X

10/26/2014 X X X X X

11/2/2014 X X X X X X

11/9/2014 X X X X X X

11/16/2014 X X X X X X X

11/23/2014 X X X X X

11/30/2014 X X X X

12/7/2014 X X

12/14/2014 X X

12/21/2014 X X X X

12/28/2014 X X X X X X

1/4/2015 X X X X X

1/11/2015 X X X X X X X X X

1/18/2015 X X X X

1/25/2015 X X X X X X

2/1/2015 X X X X X X

2/8/2015 X X X X X X

2/15/2015 X X X X X X

2/22/2015 X X X X X X

3/1/2015 X X X X X X X X X

3/8/2015 X X X X X X X

3/15/2015 X X X X X X X

3/22/2015 X X X X X X X X

3/29/2015 X X X X X X X X

4/5/2015 X X X X X X X

4/12/2015 X X X X X X X

4/19/2015 X X X X X X

4/26/2015 X X X X X X X X X

5/3/2015 X X X X X

5/10/2015 X X X X X X X

5/17/2015 X X X X X X

5/24/2015 X X X X X X X X

5/31/2015 X X X X X X X

6/7/2015 X X X X X X

6/14/2015 X X X X X X X

6/21/2015 X X X X X X
114

Table A. 12. Continued.

Sample Station code

week DS002S GS010E LP003E MK004W SF014E SJ001S SJ005N TM001N XC001N

6/28/2015 X X X X X X

7/5/2015 X X X X X X

7/12/2015 X X X X X X

7/19/2015 X X X X

7/26/2015 X X X X X X
115

Table A.13. Beach seine sites where fish samples were collected at least once within a sample 

week in the South Delta Seine Region during the 2014 field season.

Sample Station code

week MR010W OR003W OR014W OR019E OR023E SJ026S SJ032S SJ041N SJ051E WD002W

7/28/2013 X X X X X X X X X

8/4/2013 X X X X X X X X X

8/11/2013 X X X X X X X

8/18/2013 X X X X

8/25/2013 X X X X X X X X

9/1/2013 X X X X X X X X X

9/8/2013 X X X X X

9/15/2013 X X X X X X X X

9/22/2013 X X X

10/20/2013 X X X X

10/27/2013 X X X X X X X X

11/3/2013 X X X

11/10/2013 X X X X X

11/17/2013 X X X X

11/24/2013 X X X X

12/1/2013 X X X X

12/8/2013 X X X X

12/15/2013 X X X X X X X X X

12/22/2013 X X X

12/29/2013 X X X X X X X X

1/5/2014 X X X

1/12/2014 X X X X X X X X

1/19/2014 X X X

1/26/2014 X X X X X X X X

2/2/2014 X X X X

2/9/2014 X X X X X X X X

2/16/2014 X X X X X X X

2/23/2014 X X X X X X X

3/2/2014 X X X

3/9/2014 X X X X X X X X X X

3/16/2014 X X X X

3/23/2014 X X X X X X X X X

3/30/2014 X X X X X X X

4/6/2014 X X X X X X X X X

4/13/2014 X X X X X X X X X X

4/20/2014 X X X X X X

4/27/2014 X X X X X X

5/4/2014 X X X X X
116

Table A.13. Continued.

Sample Station code

week MR010W OR003W OR014W OR019E OR023E SJ026S SJ032S SJ041N SJ051E WD002W

5/11/2014 X X X X X X X X X

5/18/2014 X X X X X X X X

5/25/2014 X X X X X X

6/1/2014 X X X X

6/8/2014 X X X X X X

6/15/2014 X X X X X X X

6/22/2014 X X X X X X

6/29/2014 X X

7/6/2014 X X X X X X X

7/13/2014 X X X X

7/20/2014 X X X X

7/27/2014 X X X X
117

Table A.14. Beach seine sites where fish samples were collected at least once within a sample 

week in the South Delta Seine Region during the 2015 field season.

Sample Station code

week MR010W OR003W OR014W OR019E OR023E SJ026S SJ032S SJ041N SJ051E WD002W

8/3/2014 X X X X X

8/10/2014 X X X

8/17/2014 X X X X X X

8/24/2014 X X X

9/7/2014 X

9/14/2014 X X X X X

9/21/2014 X

9/28/2014 X X X

10/5/2014 X X X

10/12/2014 X X X X

10/19/2014 X X X X X

10/26/2014 X X

11/2/2014 X X X X X X X

11/9/2014

11/16/2014 X X X

11/23/2014 X X

11/30/2014 X X

12/7/2014 X

12/14/2014 X X X X

12/21/2014 X

12/28/2014 X

1/4/2015 X X

1/11/2015 X

1/18/2015 X X X X X

1/25/2015 X X X X

2/1/2015 X X X X X

2/8/2015 X X

2/15/2015 X X X X X X

2/22/2015 X X X X

3/1/2015 X X X X X

3/8/2015 X X

3/15/2015 X X X X X X X X X X

3/22/2015 X X X

3/29/2015 X X X X X X X X X

4/5/2015 X X X X

4/12/2015 X X X X X X X X

4/19/2015

4/26/2015 X X X X X X X X X
118

Table A.14. Continued. 

Sample Station code

week MR010W OR003W OR014W OR019E OR023E SJ026S SJ032S SJ041N SJ051E WD002W

5/3/2015 X X

5/10/2015 X X X X X X X X

5/17/2015 X X

5/24/2015 X X X X X X

5/31/2015 X X X X X X

6/7/2015 X X X X X

6/14/2015 X X

6/21/2015 X X X X X X X

6/28/2015 X X X X X X X

7/5/2015 X X X X

7/12/2015 X X

7/19/2015 X X X X X X

7/26/2015 X X X X X X X
119

Table A.15. Beach seine sites where fish samples were collected at least once within a sample 

week in the Lower San Joaquin River Seine Region during the 2014 field season. 

Sample Station code

week SJ056E SJ058W SJ063W SJ068W SJ074W SJ076W SJ077E SJ083W

7/28/2013 X X X X X X

8/4/2013 X X X X X

8/11/2013 X X X X X

8/18/2013 X X X X X

8/25/2013 X X X X X

9/1/2013 X X X X

9/8/2013 X X X

9/15/2013 X X X

9/22/2013 X X X X X

10/20/2013 X X X X X X X

10/27/2013 X X X X X X

11/3/2013 X X X X X X X

11/10/2013 X X X X X X X

11/17/2013 X X X X X X X

11/24/2013 X X X X X X X

12/1/2013 X X X X X X X

12/8/2013 X X X X X X X

12/15/2013 X X X X X X X

12/22/2013 X X X X X X X

1/5/2014 X X X X X

1/12/2014 X X X X X

1/19/2014 X X X X X

1/26/2014 X X X X X X X

2/2/2014 X X X X X X X

2/9/2014 X X X X X X X

2/16/2014 X X X X X X X

2/23/2014 X X X X X

3/2/2014 X X X X X X X

3/9/2014 X X X X X X

3/16/2014 X X X X X

3/23/2014 X X X X X

3/30/2014 X X X X X X

4/6/2014 X X X X X X

4/13/2014 X X X X

4/20/2014 X X X X X X

4/27/2014 X X X X X

5/4/2014 X X X X X X

5/11/2014 X X X X X X
120

Table A.15. Continued.

Sample Station code

week SJ056E SJ058W SJ063W SJ068W SJ074W SJ076W SJ077E SJ083W

5/18/2014 X X X X X

5/25/2014 X X X X X

6/1/2014 X X X X X

6/8/2014 X X X X X

6/15/2014 X X X X X

6/22/2014 X X X X X

6/29/2014 X X X X X

7/13/2014 X X X X X

7/27/2014 X X X X X
121

Table A.16. Beach seine sites where fish samples were collected at least once within a sample 

week in the Lower San Joaquin River Region during the 2015 field season. 

Sample Station code

week SJ056E SJ058W SJ063W SJ068W SJ074W SJ076W SJ077E SJ083W

8/10/2014 X X X X X

8/24/2014 X X X X X

9/7/2014 X X X X X

9/21/2014 X X X X X

10/5/2014 X X X X X

10/19/2014 X X X X X

11/2/2014 X X X X X

11/16/2014 X X X X X

11/30/2014 X X X X X

12/14/2014 X X X X X

12/28/2014 X X X X X

1/4/2015 X X X X X

1/11/2015 X X X X X

1/18/2015 X

1/25/2015 X X X X X

2/1/2015 X X X X X

2/8/2015 X X X X X

2/15/2015 X X X X

2/22/2015 X X X X X

3/1/2015 X X X X X

3/8/2015 X X X X X

3/15/2015 X X X X X

3/22/2015 X X X X X

3/29/2015 X X X X X

4/5/2015 X X X X

4/12/2015 X X X X X

4/19/2015 X X X X X

4/26/2015 X X X X X

5/3/2015 X X X X

5/10/2015 X X X

5/17/2015 X X X X

5/24/2015 X X X X X

5/31/2015 X X X X X

6/7/2015 X X X X X

6/14/2015 X X X X X

6/21/2015 X X X X X

6/28/2015 X X X X

7/12/2015 X X X X X

7/26/2015 X X X X X
122

Table A.17. Beach seine sites where fish samples were collected at least once within a sample 

week in the San Francisco and San Pablo Bays Region during the 2014 field season. 

Sample Station code

week SA001M SA004W SA007E SA008W SA009E SA010W SP000W SP001W SP003E

7/28/2013 X X X X X

8/4/2013 X X X

8/11/2013 X X X X X

8/18/2013 X X X

8/25/2013 X X X X

9/1/2013 X X X

9/8/2013 X X X X

9/15/2013 X X X

9/22/2013 X X X X

10/20/2013 X X X

10/27/2013 X X X X

11/3/2013 X X X X X

11/10/2013 X X X X

11/17/2013 X X X X X

11/24/2013 X X X X

12/1/2013 X X X X X

12/8/2013 X X X X

12/15/2013 X X X X

12/22/2013 X X X X

12/29/2013 X X X X X

1/5/2014 X X X X

1/12/2014 X X X X

1/19/2014 X X X X

1/26/2014 X X X X X

2/2/2014 X X X X

2/9/2014 X X X X X

2/16/2014 X X X

2/23/2014 X X X X

3/2/2014 X X X X

3/9/2014 X X X X

3/16/2014 X X X

3/23/2014 X X X X X

3/30/2014 X X X

4/6/2014 X X X X

4/13/2014 X X X

4/20/2014 X X X X

4/27/2014 X X X

5/4/2014 X X X X
123

Table A.17. Continued.

Sample Station code

week SA001M SA004W SA007E SA008W SA009E SA010W SP000W SP001W SP003E

5/11/2014 X X X

5/18/2014 X X X X

5/25/2014 X X X

6/1/2014 X X X

6/8/2014 X X X

6/15/2014 X X X X

6/22/2014 X X X X

6/29/2014 X X X

7/6/2014 X X X X

7/13/2014 X X

7/20/2014 X X X X

7/27/2014 X X
124

Table A.18. Beach seine sites where fish samples were collected at least once within a sample 

week in the San Francisco and San Pablo Bays Region during the 2015 field season.

Sample Station code

week SA001M SA004W SA007E SA008W SA009E SA010W SP000W SP001W SP003E

8/3/2014 X X X X

8/10/2014 X X

8/17/2014 X X X X

8/24/2014 X X X

8/31/2014 X X X

9/7/2014 X X X X

9/14/2014 X X X X

9/21/2014 X X X X X

9/28/2014 X X X

10/5/2014 X X X X X

10/12/2014 X X X

10/19/2014 X X X X X

10/26/2014 X X X

11/2/2014 X X X X X

11/9/2014 X X X

11/16/2014 X X X X X

11/23/2014 X X X

11/30/2014 X X X X X

12/14/2014 X X X X X

12/21/2014 X X

12/28/2014 X X X X X

1/4/2015 X X

1/11/2015 X X X

1/18/2015 X X X

1/25/2015 X X X X X

2/1/2015 X X X

2/8/2015 X X X X

2/15/2015 X X X

2/22/2015 X X

3/1/2015 X X X

3/8/2015 X X X

3/15/2015 X X X

3/22/2015 X X

3/29/2015 X X

4/5/2015 X X

4/12/2015 X X X X

4/19/2015 X X

4/26/2015 X X X X
125

Table A.18. Continued. 

Sample Station code

week SA001M SA004W SA007E SA008W SA009E SA010W SP000W SP001W SP003E

5/3/2015 X X

5/10/2015 X X X X

5/17/2015 X X

5/24/2015 X X X

5/31/2015 X X X X X

6/7/2015 X X X X

6/14/2015 X X

6/21/2015 X X X X

6/28/2015 X X X X

7/5/2015 X X X X

7/12/2015 X X X

7/19/2015 X X X X

7/26/2015 X X
126

Table A.19. Water year types for the Sacramento and San Joaquin River basins from 1978 to 

2015 (CDWR 2016). Water year types were classified as wet (W), above normal (AN), below 

normal (BN), dry (D), and critically dry (C).

Water year Water year type

Sacramento River San Joaquin River

1978 AN W

1979 BN AN

1980 AN W

1981 D D

1982 W W

1983 W W

1984 W AN

1985 D D

1986 W W

1987 D C

1988 C C

1989 D C

1990 C C

1991 C C

1992 C C

1993 AN W

1994 C C

1995 W W

1996 W W

1997 W W

1998 W W

1999 W AN

2000 AN AN

2001 D D

2002 D D

2003 AN BN

2004 BN D

2005 AN W

2006 W W

2007 D C

2008 C C

2009 D BN

2010 BN AN

2011 W W

2012 BN D
127

Table A.19. Continued.

Water year Water year type

Sacramento River San Joaquin River

2013 D C

2014 C C

2015 C C
128

Table A.20. Recoveries of all coded wire tagged juvenile winter-, fall-, late fall-, and spring-run 

Chinook Salmon by the DJFMP and fish facilities during the 2014 field season by release 

location and hatchery of origin. The hatcheries of origin included the Coleman National Fish 

Hatchery (ColemNFH), Livingston Stone National Fish Hatchery (LivinNFH), Feather River 

Fish Hatchery (FeathFH), Mokelumne River Fish Hatchery (MokeFH), San Joaquin River 

Conservation Hatchery (SanJoaqFH), and Merced River Fish Facility (MercFF; PSMFC 2017).

 

Recovery location

Release location

(hatchery of origin)

Region 1Region 2Region 3Region 4Region 5Region 6

Sacramento 

Trawl Site

Mossdale

Trawl Site

Chipps Island

Trawl Site

DJFMP total

Winter-run

 Caldwell Park (LivinNFH) 0 0 0 0 0 0 13 0 18 31

Fall-run

Battle Creek (ColemNFH) 0 0 0 0 0 0 89 0 66 155

Sac. R. at Rio Vista (ColemNFH) 0 2 0 0 0 0 0 0 157 159

Sac. R. at Rio Vista (FeathFH) 0 1 0 0 0 0 0 0 12 13

Wickland Oil Net Pen (FeathFH) 0 0 0 0 0 0 0 0 8 8

Yolo Bypass (FeathFH) 0 0 0 0 0 0 0 0 1 1

San Joaq. R. Jersey Pt. (MercFH) 0 0 6 0 0 0 0 0 71 77

San Joaq. Shrm. Is. Net Pen (MokeFH) 0 0 0 0 0 0 0 0 129 129

San Joaq. R. Friant Net (SanJoaqFH) 0 0 0 0 0 0 0 1 0 1

San Joaq. R. Ab. Merced (SanJoaqFH) 0 0 0 0 0 0 0 6 0 6

Late fall-run

Battle Creek (ColemNFH) 3 9 0 0 0 0 47 0 88 147

Spring-run

Feather at Gridley (FeathFH) 2 12 2 0 0 0 90 0 112 1

Feather Boyds pump ramp (FeathFH) 0 0 0 0 0 0 294 0 27 321

Mare Is. Net Pen (FeathFH) 0 0 0 0 0 0 0 0 1 1

San Joaq. R. at Merced (FeathFH) 0 0 0 0 0 0 0 2 0 2

Unknown 0 0 1 0 0 0 3 3 7 14
129

Table A.21. Recoveries of all coded wire tagged juvenile winter-, fall-, late fall-, and spring-run 

Chinook Salmon by the DJFMP during the 2015 field season by release location and hatchery of 

origin. The hatcheries of origin included the Coleman National Fish Hatchery (ColemNFH), 

Livingston Stone National Fish Hatchery (LivinNFH), Feather River Fish Hatchery (FeathFH), 

Mokelumne River Fish Hatchery (MokeFH), Nimbus Fish Hatchery (NimbFH), and Merced 

River Fish Facility (MercFF; PSMFC 2017).

 

Recovery location

Release location

(hatchery of origin)

Region 1Region 2Region 3Region 4Region 5Region 6

Sacramento 

Trawl Site

Mossdale Trawl 

Site

Chipps Island 

Trawl Site

DJFMP total

Winter-run

 Caldwell Park (LivinNFH) 4 4 0 0 0 0 86 0 80 174

Fall-run

Sac. R. at Rio Vista (ColemNFH) 0 2 0 0 0 0 0 0 271 273

Mare Is. Net Pen (FeathFH) 0 0 0 0 0 1 0 0 3 4

San Joaq R. Jersey Pt (MercFH) 0 0 0 0 0 0 0 0 36 36

San Joaq Shrm. Is. Net Pen

(MokeFH)

0 0 0 0 0 0 0 0 149 149

Wickland Oil Net Pen (NimbFH) 0 0 0 0 0 0 0 0 2 2

Late fall-run

Battle Creek (ColemNFH) 0 0 0 0 0 0 2 0 13 15

Spring-run

Feather at Gridley (FeathFH) 0 2 0 0 0 0 28 0 0 30

Feather Boyds pump ramp 

 (FeathFH)

0 1 0 0 0 0 13 0 1 15

San Joaq. R. Ab. Merced

(FeathFH)

0 0 0 0 0 0 0 2 0 2

Unknown 1 0 0 0 0 0 7 0 18 26
130

Table A.22. Total adult Chinook Salmon escapement estimates by race for the Sacramento and 

San Joaquin River basins from 1978 to 2015 (CDFW 2016).

Year Winter-run Fall-run Late fall-run Spring-run

1978 25,012 156,962 12,479 8,126

1979 2,364 227,646 10,284 3,116

1980 1,156 172,137 9,093 12,464

1981 22,797 260,259 6,718 22,105

1982 1,281 230,706 6,899 27,890

1983 1,831 205,290 15,089 7,958

1984 2,763 262,907 10,388 9,599

1985 5,407 356,304 10,180 15,221

1986 2,596 297,820 8,301 25,696

1987 2,185 301,583 16,571 13,888

1988 2,878 268,436 13,218 18,933

1989 696 182,350 12,872 12,163

1990 430 87,853 8,078 7,683

1991 211 132,455 8,263 5,926

1992 1,240 110,413 10,131 3,044

1993 387 165,423 1,267 6,076

1994 186 220,667 889 6,187

1995 1,297 330,168 489 15,238

1996 1,337 351,551 1,385 9,083

1997 880 402,797 4,578 5,193

1998 2,992 246,026 42,419 31,649

1999 3,288 414,259 15,758 10,100

2000 1,352 485,681 12,883 9,244

2001 8,224 624,631 21,813 26,663

2002 7,441 872,669 40,406 25,043

2003 8,218 590,992 8,882 30,697

2004 7,869 386,848 14,150 17,150

2005 15,839 437,693 16,282 23,093

2006 17,296 292,954 15,089 12,906

2007 2,541 97,168 18,843 11,144

2008 2,830 71,291 10,372 13,387

2009 a4,537 53,129 10,196 4,429

2010 a1,596 163,189 9,986 4,623

2011 a827 227,598 8,448 7,774

2012 a2,671 340,819 5,986 22,426

2013 a6,084 447,621 9,004 23,696
131

Table A.22. Continued.

Year Winter-run Fall-run Late fall-run Spring-run

2014 a3,015 256,220 13,050 9,901

2015 a3,440 152,663 9,347 5,635

a

indicates years containing preliminary data
132

Table A.23. The number of juvenile fish samples collected (i.e., number of days samples were 

collected) at seine sites by sample week in the Sacramento Area Beach Seine Region during the 

2014 field season.

Sample Station code

week AM001S SR049E SR055E SR057E SR060E SR062E SR071E SR080E

10/13/2013 1 1 1 1 1 1 1 1

10/20/2013 1 3 3 3 3 3 3 3

10/27/2013 1 3 3 3 3 3 3 3

11/3/2013 1 3 3 3 3 3 3 3

11/10/2013 1 3 3 3 3 3 3 3

11/17/2013 1 3 3 3 3 3 3 3

11/24/2013 1 3 3 3 3 3 3 3

12/1/2013 1 3 3 3 3 3 3 3

12/8/2013 1 3 3 3 3 3 3 3

12/15/2013 1 3 3 3 3 3 3 3

12/22/2013 1 3 3 3 3 3 3 3

12/29/2013 1 3 3 3 3 3 3 3

1/5/2014 1 3 3 3 3 3 3 3

1/12/2014 1 3 3 3 3 3 3 3

1/19/2014 1 3 3 3 3 3 3 3

1/26/2014 1 3 3 3 3 3 3 3
133

Table A.24. The number of juvenile fish samples collected (i.e., number of days samples were 

collected) at seine sites by sample week in the Sacramento Area Beach Seine Region during the 

2015 field season.

Sample Station code

week AM001S SR049E SR055E SR057E SR060E SR062E SR071E SR080E

10/5/2014 1 3 3 3 3 3 3 3

10/12/2014 1 3 3 3 3 3 3 3

10/19/2014 1 3 3 3 3 3 3 3

10/26/2014 1 3 3 3 3 3 3 3

11/2/2014 1 3 3 3 3 3 3 3

11/9/2014 1 3 3 3 3 3 3 3

11/16/2014 1 3 3 3 3 3 3 3

11/23/2014 1 3 3 3 3 3 3 3

11/30/2014 1 3 3 3 3 3 3 3

12/7/2014 1 3 3 3 3 3 3 3

12/14/2014 0 2 2 2 2 2 2 2

12/21/2014 1 2 2 2 2 2 2 2

12/28/2014 1 3 3 3 3 3 3 3

1/4/2015 1 2 2 2 2 2 2 2

1/11/2015 0 1 1 1 1 1 1 1

1/18/2015 1 1 1 1 1 1 1 1

1/25/2015 0 1 1 1 1 1 1 1
134

APPENDIX B

Table B.1. Sites sampled during the 2014 and 2015 field seasons in the Liberty Island region. 

Station codes refer to body of water (first 2 letters; LI = Liberty Island), river mile (3 digits), and 

location within site (last letter; W=west, E=east).

Coordinates (UTM)

Site code Site name County Zone Northing Easting First Year Sampled 

Annually

LI001E Liberty Island Solano 10 S 4233484 615314 2003

LI001W Liberty Island Solano 10 S 4237405 614211 2003

LI002E Liberty Island Solano 10 S 4233976 615669 2003

LI002W Liberty Island Solano 10 S 4236504 614473 2003

LI003E Liberty Island Solano 10 S 4234947 616186 2003

LI003W Liberty Island Solano 10 S 4235240 614589 2003

LI004E Liberty Island Solano 10 S 4236068 616215 2003

LI004W Liberty Island Solano 10 S 4234667 614948 2003

LI005E Liberty Island Solano 10 S 4237032 616606 2003

LI005W Liberty Island Solano 10 S 4233771 614947 2003

LI006E Liberty Island Solano 10 S 4237439 616681 2010

LI006W Liberty Island Solano 10 S 4237938 614369 2010

LI007E Liberty Island Solano 10 S 4238168 616711 2010

LI007W Liberty Island Solano 10 S 4237974 614799 2010

LI008E Liberty Island Solano 10 S 4238755 616557 2010

LI008W Liberty Island Solano 10 S 4238529 614390 2010

LI009E Liberty Island Solano 10 S 4239755 616494 2010

LI009W Liberty Island Solano 10 S 4238968 614405 2010

LI010E Liberty Island Solano 10 S 4240225 616485 2010

LI010W Liberty Island Solano 10 S 4240155 614452 2010

LI011E Liberty Island Solano 10 S 4241450 616478 2010
135

Table B.2. Total of individuals observed in samples used to assess the fish assemblage structure 

during the 2014 field season. Counts are grouped by species. Fish species are listed in 

phylogenetic order. 

Fish species Liberty Island 

American Shad Alosa sapidissima 69

Threadfin Shad Dorosoma petenense 97

Common Carp Cyprinus carpio 3

Fathead Minnow Pimephales promelas 7

Splittail Pogonichthys macrolepidotus 3

Sacramento Pikeminnow Ptychocheilus grandis 6

Sacramento Sucker Catostomus occidentalis 6

White Catfish Ameiurus catus 6

Channel Catfish Ictalurus punctatus 1

Delta Smelt Hypomesus transpacificus 6

Chinook Salmon Oncorhynchus tshawytscha 431

 Unmarked winter-run 1

 Unmarked fall-run 426

 Unmarked spring-run 4

Inland Silverside Menidia beryllina 15312

Rainwater Killifish Lucania parva 1

Western Mosquitofish Gambusia affinis 6

Prickly Sculpin Cottus asper 22

Pacific Staghorn sculpin Leptocottus armatus 2

Striped Bass Morone saxatilis 218

Bluegill Lepomis macrochirus 1

Redear Sunfish Lepomis microlophus 3

Spotted Bass Micropterus punctulatus 2

Largemouth Bass Micropterus salmoides 21

Bigscale Logperch Percina macrolepida 21

Tule Perch Hysterocarpus traskii 88

Yellowfin Goby Acanthogobius flavimanus 310

Shimofuri Goby Tridentiger bifasciatus 55
136

Table B.3. Total of individuals observed in samples used to assess the fish assemblage structure 

during the 2015 field season. Counts are grouped by species. Fish species are listed in 

phylogenetic order. 

Fish species Liberty Island 

American Shad Alosa sapidissima 45

Threadfin Shad Dorosoma petenense 451

Common Carp Cyprinus carpio 6

Golden Shiner Notemigonus crysoleucas 5

Splittail Pogonichthys macrolepidotus 10

Sacramento Pikeminnow Ptychocheilus grandis 29

Sacramento Sucker Catostomus occidentalis 5

Wakasagi Hypomesus nipponensis 1

Delta Smelt Hypomesus transpacificus 2

Chinook Salmon Oncorhynchus tshawytscha 11

 Unmarked fall-run 11

Inland Silverside Menidia beryllina 11144

Rainwater Killifish Lucania parva 1

Western Mosquitofish Gambusia affinis 53

Prickly Sculpin Cottus asper 2

Striped Bass Morone saxatilis 153

Bluegill Lepomis macrochirus 15

Redear Sunfish Lepomis microlophus 32

Smallmouth Bass Micropterus dolomieu 1

Largemouth Bass Micropterus salmoides 33

Black Crappie Pomoxis nigromaculatus 1

Bigscale Logperch Percina macrolepida 77

Tule Perch Hysterocarpus traskii 2

Yellowfin Goby Acanthogobius flavimanus 34

Shimofuri Goby Tridentiger bifasciatus 86
137

Table B.4. Recoveries of coded wire tagged juvenile Chinook Salmon by the DJFMP in the 

Liberty Island seine region from 2003 to 2015 by release location and hatchery of origin. The 

hatcheries of origin included the Coleman National Fish Hatchery (ColemNFH), Feather River 

Fish Hatchery (FeathFH), and Nimbus Fish Hatchery (NimbFH) (MercFF; PSMFC 2014).

Field 

Season Release location (hatchery of origin) Race

Number of 

individuals 

recovered

2003 Sac. R at Vierra's Resort (FeatFH) Fall-run 1

Sac. R at Elkhorn Boat Ramp (FeatFH) Fall-run 1

Sac. R at West Sacramento (FeatFH) Fall-run 3

Feather at Live Oak (FeatFH) Fall-run 1

Unknown Unknon 1

2004 Yolo Bypass (FeatFH) Fall-run 1

2005 no recoveries 0

2010 Coleman NFH (ColemNFH) Late fall-run 1

2011 Coleman NFH (ColemNFH) Late fall-run 1

Sac. R at Discovery Park (NimbFH) Fall-run 2

2012 Coleman NFH (ColemNFH) Late fall-run 1

2013 no recoveries 0

2014 no recoveries 0

2015 no recoveries 0
138

Table B.5. Seine sites where fish samples were collected at least once within a sample week in the Liberty Island Seine Region during 

the 2014 field season.

Station code

Sample

week

LI001ELI001WLI002ELI002WLI003ELI003WLI004ELI004WLI005ELI005WLI006ELI006WLI007ELI007WLI008ELI008WLI009ELI009WLI010E

8/11/2013 X X X X X X

8/25/2013 X X X X X X X

9/8/2013 X X X X X

9/22/2013 X X X X X X

10/20/2013 X X X X X

11/3/2013 X X

11/10/2013 X X X X X X

11/24/2013 X X X X X X

12/1/2013 X X

12/8/2013 X X X X

12/15/2013 X X X X X X X X X

12/29/2013 X X X X

1/12/2014 X X X X X X X X X

1/26/2014 X X X X X

2/2/2014 X X X X X X

2/16/2014 X X X X X X X X

3/2/2014 X X X X X X X X X X

3/16/2014 X X X X X X X X

3/30/2014 X X X X X X X X X X

4/13/2014 X X X X X X

4/27/2014 X X X X X X X X X X X X X

5/11/2014 X X X X X X X

5/25/2014 X X X X X X X X X X

6/8/2014 X X X X X X X X X

6/22/2014 X

6/29/2014 X X X X X X

7/6/2014 X X X X X X X

7/20/2014 X X X X
139

Table B.6. Seine sites where fish samples were collected at least once within a sample week in the Liberty Island Seine Region during 

the 2015 field season.

Station code

Sample 

week

LI001ELI001WLI002ELI002WLI003ELI003WLI004ELI004WLI005ELI005WLI006ELI006WLI007ELI007WLI008ELI008WLI009ELI009WLI010E

8/10/2014 X X X X X X X

8/24/2014 X X X X X X X

8/31/2014 X X X X X X X X X

9/14/2014 X X X X X X

9/28/2014 X X X X X X X X X

10/12/2014 X X X X X X X X

10/26/2014 X X X X X X

11/9/2014 X X X X X X X

11/23/2014 X X X X X X X X

11/30/2014 X X X X X X

12/14/2014 X X X X X X

12/28/2014 X X X X X X X

1/11/2015 X X

1/25/2015 X X X X X X

2/8/2015 X X X X X X X X

2/15/2015 X X X X X X X

3/1/2015 X X X X X X

3/15/2015 X X X X X

3/29/2015 X X X X X X

4/5/2015 X X X X X X

4/12/2015 X X X X X

5/10/2015 X X X X

5/24/2015 X X X

6/14/2015 X X X X

6/21/2015 X X X X

7/5/2015 X X X X X X

7/19/2015 X X X