Catfish in the South Delta - Hydroacoustic Technology, Inc.

Catfish in the South Delta: Investigations into Species Interaction
Laura Rudolph (1), Veronica Wunderlich (2), and Kevin Kumagai (1)
(1) Hydroacoustic Technology, Inc. (HTI), 715 NE Northlake Way, Seattle, WA; (2) CA Dept. of Water Resources, Delta Conveyance Fish Science, 1416 9th St., Sacramento, CA
Email : support@HTIsonar.com
Results Continued…
Abstract
Display Methods
North American catfish (Ictaluridae) are native to areas east of the Rocky Mountains. Since catfish are
an introduced species to the Sacramento-San Joaquin Delta, conflicts may arise with native fish
species such as threatened and endangered Pacific salmonids (Oncorhynchus spp.). Acoustic tagging
was used to better understand species interactions, between predatory fishes and native fish species.
By tagging the predators of juvenile salmonid populations, researchers may gain a better
understanding of the feeding and schooling behaviors of these species. While predatory fishes such as
striped bass (Morone saxatilis) and largemouth bass (Micropterus salmoides) were predominately
tagged, catfish were also tagged. In this poster, we examine catfish movement in and around the
Clifton Court Forebay in Tracy, California using an acoustically tagged catfish as our primary example.
Catfish movement is graphically displayed in Eonfusion providing a snapshot of migration and/or
feeding behavior in the South Delta. Ultimately, understanding species interaction may help mitigate
predation and restore endangered native fish populations in the Sacramento-San Joaquin Delta.
Catfish movements were graphically displayed in the Clifton Court Forebay and surrounding areas
using Eonfusion (Figures 3-8). In addition, fish salvage for the State Water Project (SWP) and the
Central Valley Project (CVP) (CDFW 2015) were graphed and synchronized with the catfish
movement detections (Figures 6-8).
Site Location
The field work took place at the Clifton Court Forebay (forebay) in Tracy, California (Figure 1). The
forebay serves as necessary water storage for the State of California. On the southeastern side of the
forebay, Area 1 (Figure1), the radial gates open and close allowing water to flow from the SacramentoSan Joaquin Delta (Delta) into the Clifton Court Forebay. As the gates open, fish can pass through the
gates and into the forebay, or swim back into the Delta. Fish may be salvaged at the Skinner Fish
Facility if they do not exit the forebay through the radial gates.
Results
Catfish 8119.01 was caught on May 31st, 2013 and was classified as a white catfish (Ameiurus
catus) with a length of 48.5 centimeters, and a weight of 3.8 pounds. The fish began near the radial
gates where it was released (Figure 4). It then travelled across the forebay and into the intake
canal. After being detected in the intake canal, the catfish found its way back to the radial gates and
then traveled out of the forebay and into West Canal (Figure 5). The fish was detected in West
Canal and at the Old River south (ORS1) site (Figure 6). This pattern of swimming up and down
West Canal and then towards the radial gates continued for months. On August 27th, 2013 the
catfish is detected back inside the forebay at the downstream radial gates site. This demonstrates
the catfish’s ability to swim within the forebay array freely, potentially searching for food and
exhibiting predatory-like behavior. By observing this catfish’s movement we can better determine
whether or not the fish is displaying predatory-like behavior.
Figure 3.
Eonfusion snapshot provides
a visual of every site where
catfish 8119.1 has been
detected in the Clifton Court
Forebay array. The bottom
bar provides the time line
this catfish was detected in
the system.
Salvage data from the State Water Project and the Central Valley Project were graphically
displayed to show the correlation between catfish movement and the increase in threadfin
shad (Dorosoma petenense) salvaged from CVP (Figure 7). The catfish was detected at
ORS1 (Figure 6) presumably when the shad began to travel south toward the collection
facility. The catfish was no longer detected when the large spike in shad is salvaged, and
we assume that the catfish continued south with the prey (Figure 7). Then after the spike,
the catfish returned to the Clifton Court Forebay, and was detected at ORS1 and the radial
gates upstream location (Figure 8).
Figure 6.
Last catfish
detection in the
Clifton Court
Forebay array
before traveling
out of the hydrophone detection
range for a short
period of time,
presumably
traveling south
for prey.
Figure 7.
Large spike in
salvage data from
the Central Valley
Project. The
catfish’s absence
from Clifton Court
may be connected
with the spike in
threadfin shad, and
its potential search
for food.
Figure 1. Clifton Court Forebay, Tracy CA. Pin points mark hydrophone array for the Clifton
Court Forebay Predation Study.
Field Methods
Figure 4.
First detection of catfish
8119.01 at the radial gates
down-stream location.
Hook and line sampling was the primary capture method. The catfish highlighted in this
poster was caught using bait in Area 3 of the Clifton Court Forebay (Figure 1). Once caught,
the fish was anesthetized using AQUI-S 20E. The catfish (similar to the fish pictured in Figure
2) was then tagged using a combination acoustic tag (period and sub code of 8119.01) with
an integrated PIT tag. The fish was additionally Floy tagged for quick visual identification in
case of recapture. Once recovered, the catfish was released back into the Clifton Court
Forebay at the point of capture.
Figure 5.
First detection of catfish
8119.01 outside of the
Clifton Court Forebay at
radial gates upstream
on June 28th, 2013 at
4:05 AM. (First
documentation of a
tagged catfish leaving
the Clifton Court
Forebay.)
Figure 8.
Catfish detections
(returning to the
hydrophone array
presumably after
following the
increased number of
shad south, that were
salvaged at the Tracy
Collection Facility).
Conclusion
Catfish movement in and out of the Clifton Court Forebay was documented. This movement may have
been in response to prey availability (i.e., threadfin shad). Using tools such as acoustic tags and
Eonfusion, we can create detailed timelines of when and where fish travel in and around the Clifton
Court Forebay. This information is helpful in understanding more about catfish behavior, as well as
what factors motivate this behavior. By incorporating environmental factors with catfish movement we
can create a more complete picture of why the catfish are driven to various areas of the south delta,
such as prey.
Figure 2. White Catfish (Ameiurus catus). Image Courtesy: Veronica Wunderlich, (CA DWR)
References
California, Department of Fish and Wildlife. "Bay Delta Region (East)." Web. 26 Mar. 2015.
Salvage Monitoring
http://www.dfg.ca.gov/delta/apps/salvage/
Acknowledgements
A big thank you to California Department of Water Resources, Delta Conveyance Fish - Science
Section, Biotelemetry and Special Investigations Unit for driving the efforts to make this research
possible.