programs of the fish conservation and culture...

8/4/2014

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Programs of the Fish Conservation and Culture Laboratory

Joan Lindberg1, Tien-Chieh Hung1, Meredith Nagel1,2

1 Fish Conservation and Culture Laboratory, UC Davis2 Aquatic Health Program, UC Davis

Delta Smelt (Hypomesus transpacificus)

• Endemic to Bay‐Delta

• Endangered species status

• Annual life‐span

• Spawning season February – June

• Asynchronous batch‐spawner (multiple clutches)

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Main Programs of FCCL

• Delta Smelt Refuge Program– Develop and implement genetic breeding and rearing program

• Research Program and Collaborative studies– Reproductive biology, behavior studies, growth and development

studies

• Aquaculture Program– Produce Delta Smelt and Longfin Smelt for on‐site and off‐site research

Selected studies

• Spawn responses to naturalistic substrates and water velocities

• Effects of light and turbidity on feeding, growth, and survival of larval Delta Smelt

• Effects of temperature and salinity on the choices of Delta Smelt

• Effects of food‐limitation on the life‐stages of Delta Smelt

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Spawn Responses to Naturalistic Substrates and Water Velocities

Joan Lindberg1, Brittany Kammerer1,2, Bradd Baskerville-Bridges1


Experimental Spawning Tanks

Two zones of velocity, over two years, 100 fish/tank

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ET B T AT P W

Ln

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Substrate

1.4 cm/sec

8.8 cm/sec

4a 23b

A

4b

23b23b

23a3a

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ET C T S P W

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15.8 cm/sec

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2a12a

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1a1a

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Substrate types:

Empty trays (ET)Bare tank floor (B)Tule plant stalks (T)Artificial tules (AT)Pebble (P)Dead wood (W)Cobble (C)Sand (S)

Deposition of Eggs

• Most of the eggs were found on the substrates (58.5±14.6%) as opposed to the trays (4.5±4.1%).

• More eggs were deposited on the pebble and sand.

• Delta Smelt choose to spawn on substrates in the high flow velocity, each year.

Results Summary

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Effects of Light and Turbidity on Feeding, Growth, and Survival of Larval Delta Smelt

Galen Tigan, Tien-Chieh Hung, Joan Lindberg

Fish Conservation and Culture Laboratory, UC Davis

Baskerville-Bridges et al. (2000)

Delta Smelt First Feeding Study

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• Three levels of turbidity (2.0, 5.5, and 9.0 NTU) and light intensity (2.0, 6.75, and 9.0 µmole/m2/sec).

• Sampled on Day 10, 20, 30, and 40.

40-day Rearing Study

Survival (%) Growth rate (mm/day)

Survival and Growth

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Growth rate (mm/day)

DPH

2.0µmol/9.0NTU(2)

9.0µmol/9.0NTU(2)

9.0µmol/9.0NTU(1)

6.75µmol/5.5NTU(2)

4.5µmol/2.0NTU(1)

9.0µmol/2.0NTU(1)

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Feeding Preference

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Number of larvae

10 DPH

9.0 µmole9.0 NTU(1)






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Number of larvae

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• The presence of turbidity and light triggered feeding in Delta Smelt larvae.

• The survival and growth rate are higher for Delta Smelt larvae in the rearing trial with high turbidity conditions.

• The co‐feeding period is shorter for Delta Smelt larvae reared under low turbidity conditions.

• Future work: different life stages and species (Longfin Smelt)

Results Summary

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Effects of Temperature and Salinity on the Choices of Adult Delta Smelt

Tien-Chieh Hung1,*, Swee Teh2, Saikrithika Gandhi2, Joan Lindberg1


Shuttlebox System

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Acclimated to 14ºC Acclimated to 17ºC

Fish Choice at Several Temps5 and 3 trials/ treatment

23ºC 25ºC

Fish Choice at Several Salinity

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• Temperature trials– 23ºC for fish acclimated to 14ºC

– 25ºC for fish acclimated to 17ºC

• Salinity trials– No significant movement to a specific salinity

– Avoiding high salinity, as the salinity increased

• Future work– Other stimuli: turbidity, toxicity, other

Results Summary

Investigating the Effects of Food-Limitation on the Life-Stages of Delta Smelt

Meredith Nagel1,2, Joan Lindberg1, Swee Teh2


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Food web interactions: bottom‐up conceptual model of the Pelagic Organism Decline

Declining Fish Abundances in the Delta

Declining Fish Populations

• Invasive species• Drought

• Reduced food availabilityfor pelagic fish

• Changes in zooplankton abundance and community composition

Adult Population

• Reproductive development

• Seasonal fecundity

• Overall fish health

Subsequent Generation

• Egg and larval quality

• Larval development and survival

• Maternal provisioning

Quantifying the Effects of Food-Limitation

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• Potential low food availability in fall, coupled with warmer temperatures

• Less is known about winter food‐limitation

Mar

Winter Food-Limitation ?

Experimental Design

• Three replicates, control and food‐limited (n=3)

• 250 fish per tank

• Each fish is uniquely tagged

Photos by Marade Sandford

Adult Delta Smelt Winter Food-Limitation Study

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• 10 ‐12 fish dissected for biomarker assays

• 40 fish measured for weight and length every 2 weeks

• Constant temperature at 12°C

Dec Jan Feb March April May June

8 week food‐limitation period

Collect fecundity, histology, and biomarker data

12° C

10° C

Experimental Design

Control tanks fed 2% of body weight per day

Food‐limited tanks fed 2% of body weight 4 days/week (40% reduced ration)

C1 FL1 C2 C3 FL2 FL3

Experimental Design: Food-limitation

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– Eggs expressed

– Measured for weight, length, and ova weight

– Females returned to tank

– Estimate the number of eggs

C1 FL1 C2 C3 FL2 FL3

Experimental Design: Fecundity Indices

• RNA/DNA – short term energy storage

• Triglycerides (TAG) – long term energy storage

• Histopathology

• Estradiol – maturation

• Fatty‐Acid analysis

• Disease

Nutritional and General Health Biomarkers

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020406080

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1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

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Weight (g)

Frequency Distribution Control Groups in March

020406080

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1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

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Frequency Distribution Food-Limited Groups in March

Results:

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45 50 55 60 65 70 75 80 85 90 95

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Length (mm)

Frequency Distribution of Length in Control Groups

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Frequecy Distribution of Length in Food-Limited Groups

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• No significant difference in condition factor

Results: Spawning

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Control Food-Limited

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Average Weight at First Clutchp = 0.01n = 3

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Results: Spawning

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Total Number of Spawned Females

ControlFood-Limited

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Average First Clutch Size

p = 0.02n = 3

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1st Clutch 2nd Clutch 3rd Clutch

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Total Number of Eggs per Clutch

Control

Food-Limited

Total difference of 114,440 eggs spawned

Results: Fecundity

• Omega‐3’s important in growth, neural development, and immune system functions

• Omega‐3/Omega‐6 ratios may have pivotal role in egg and larval quality

2013 Pilot Study: Fatty Acid Analysis

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Σn-6 Σn-3

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Percent Composition of Omega-3 (n-3) and Omega-6 (n-6) Fatty

Acids in EggsControlFood-Limited

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Control

Food-Limited

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Results: Spawning and Clutch Interval

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1/30/14 2/20/14 3/13/14 4/3/14 4/24/14 5/15/14

Nu

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ipe

Fem

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Spawn Date

Number of Ripe Females for Control and Food-Limited Groups

Control Clutch 1Food-Limited Clutch 1Control Clutch 2Food-Limited Clutch 2

• Smaller individuals leads to fewer offspring

• Adult food‐limitation may affects larval survival by:

– Egg and larval quantity and quality

• Impacting population abundances in subsequent year

Photo by Marade Sandford

Potential Implications for Delta Smelt

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• How does food‐limitation impact other life‐stages of the delta smelt?

Juveniles ?

?

Moving Forward…. New Questions!

• The number of fish surviving to maturity to enter the

adult population

Density‐Independent Density‐Dependent

• Temperature

• Food conditions

• Competition

• Predation

What is Recruitment?

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• Changes in fish populations are primarily driven by variability in recruitment

• Eggs and larvae suffer the greatest losses – most considered natural mortality

Population Dynamics

Zooplankton Larval SurvivalJuvenile Recruits Adult Population

Smaller adults, fewer individuals spawning, fewer eggs

AdultsEggs and LarvaeLower quality, reduced survival

JuvenileHigher mortality, smaller fish, decreased recruitment

Food-Limitation and Population Dynamics

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Juvenile food‐limitation: Impacts on recruitment and population dynamics?

• Small alterations to juvenile growth and survival can have massive repercussions on recruitment and the adult population

Objectives:Evaluate food‐limitation on the old and young cohort of a season in terms of:

1.) Growth2.) Survival3.) Subsequent impacts on adult fecundity4.) Temperature

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Extra slides

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1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Nu

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Weight (g)

Frequency Distribution in March

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