Your Hudson guides for today!

Margie Turrin

Laurel Zaima

mkt@ldeo.columbia.edu

lzaima@ldeo.columbia.edu

1. Water �2. Gills �3. Scales �4. Fins�5. Eggs �6. Tail�

Poll #2: What Defines a Fish?

What defines a fish?

2. Gills

4. Fins

6. Tails

3. Scales

5. Eggs

1. Water

Yes! All fish live under fresh or salty water, and they have special adaptations to do so!

2. Gills

4. Fins

6. Tails

3. Scales

5. Eggs

What defines a fish?

Mangrove Killifish

Wikimedia Commons

Yes! All fish have gills to breathe underwater, and this unique feature allows them to live underwater.

Yes! All fish live under fresh or salty water, and they have special adaptations to do so!

4. Fins

6. Tails

3. Scales

5. Eggs

What defines a fish?

Lungfish

Wikimedia Commons

While MOST fish have scales… not all of them do. Keep trying!

Yes! All fish have gills to breathe underwater, and this unique feature allows them to live underwater.

Yes! All fish live under fresh or salty water, and they have special adaptations to do so!

4. Fins

6. Tails

5. Eggs

What defines a fish?

Naked Goby

White Catfish

Florida Museum of Natural History

Florida Museum of Natural History

Yes! All fish have fins to help move and maneuver through their aquatic environment. However, not all fish have the same type or number of fins

While MOST fish have scales… not all of them do. Keep trying!

Yes! All fish have gills to breathe underwater, and this unique feature allows them to live underwater.

Yes! All fish live under fresh or salty water, and they have special adaptations to do so!

6. Tails

5. Eggs

What defines a fish?

Leisure Pro

Actually, not all fish lay eggs! Different fishes can either lay eggs (oviparous), live birth (viviparous), or hatch eggs inside their body before birthing into the environment. (Ovoviviparous).

Yes! All fish have fins to help move and maneuver through their aquatic environment. However, not all fish have the same type or number of fins

While MOST fish have scales… not all of them do. Keep trying!

Yes! All fish have gills to breathe underwater, and this unique feature allows them to live underwater.

Yes! All fish live under fresh or salty water, and they have special adaptations to do so!

6. Tails

What defines a fish?

NYSDEC

Sturgeon Eggs

Yes! All fish have tails, but depending on the species those tails differ in shape.

Actually, not all fish lay eggs! Different fishes can either lay eggs (oviparous), live birth (viviparous), or hatch eggs inside their body before birthing into the environment. (Ovoviviparous).

Yes! All fish have fins to help move and maneuver through their aquatic environment. However, not all fish have the same type or number of fins

While MOST fish have scales… not all of them do. Keep trying!

Yes! All fish have gills to breathe underwater, and this unique feature allows them to live underwater.

Yes! All fish live under fresh or salty water, and they have special adaptations to do so!

What defines a fish?

Like Humans:

• Brain
• Eyes
• Nostrils
• Heart
• Liver
• Intestines

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Unlike Humans:

• Gills
• Swim Bladder
• Fins types
• Mouth Directionality
• Lateral Line
• Barbels
• Form

Fish Anatomy

Mouth Shape & Direction

• Long skinny bill
• Poking into crevices
• Large mouth
• Swallowing
• Beaklike mouth
• Extract shellfish from their shells, sometimes breaking the shell
• Downward
• Suck food up off floor
• Upward-orientated
• Feed at water surface

Clearwater

Clearwater

Chesapeake Bay Program

Current Seams

Flickr

Striped Bass

Pipefish

Northern

Puffer

Atlantic Sturgeon

Banded Killifish

Barbels

Barbels:

Slender, whisker-like sensory organ near the mouth

House the taste buds and help them search for food in the sediment

Atlantic Sturgeon

Shortnose Sturgeon

Channel Catfish

White Catfish

Clearwater

Clearwater

Color

Cryptic coloration

Camouflage to match background

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Counter shading

Dorsally darkened and ventrally whitened

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Disruptive coloration

Stripes and multiple colors break up the outline of the fish

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Eye spot (false eye)

Located near the tail to confuse predators

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Clearwater

Clearwater

Clearwater

Swim Bladder

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Maintains Neutral Buoyancy

Earthlife.net

Lateral line

Lateral line

Clearwater

Adult White Perch

Juvenile White Perch

Gills

Activity: Sampling on the Hudson River Estuary �Testing For Fish Diversity

• One sunny June day a group met at the Hudson River to see the diversity of fish living in the water.
• They decided to travel to 3 different placed on the river to sample fish. See the map - #1, #2, #3.
• One participant asked why they should spend time going to 3 places because:
• It is all one river. Won’t the fish be about the same everywhere?
• Traveling takes time that could be spent collecting more samples at 1 place.

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Sampling on the Hudson River Estuary �Testing For Fish Diversity.

• One sunny June day a group met at the Hudson River to see the diversity of fish living in the water.
• They decided to travel to 3 different placed on the river to sample fish. See the map - #1, #2, #3.
• One participant asked why they should spend time going to 3 places because:
• It is all one river. Won’t the fish be about the same everywhere?
• Traveling takes time that could be spent collecting more samples at 1 place.

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• What do you think? Would the group better understand the fish in the river from:
• More samples at 1 site?
• Fewer samples at 3 sites?

We need to know a few things to answer that question!

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• Beacon Waterfront Park in Beacon (River Mile 61)

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• Croton Point Park in Croton (River Mile 35)

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• Center for the Urban River at Beczak in Yonkers (River Mile 18)

Atlantic Ocean - salinity ~35 ppt

Freshwater input - salinity > .01 ppt

• This map is of the lower half of the Hudson. For this 153 miles the Hudson is not just a river, it is an estuary!
• An estuary is where a freshwater river meets a saltwater ocean, with tides and salty water affecting the river.
• The Hudson meets the Atlantic Ocean down by New York Harbor.
• The 3 sampling sites are all in the lower half of the estuary. Will the fish differ in these few miles?
• What do you think should we sample at 3 sites or 1?

#3

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#2

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#1

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Hudson River Estuary is 153 miles from Albany to the lowest part of NYC

How will we sample fish? What is our ‘method’? Seining!

John Waldman, from Queens College, City University of New York led the fishing. He used a seine net (below) to catch the fish. In seining fish are scooped into the net as you walk through the water pulling the net behind.

In order to understand our fish catch we need to look at river conditions

The group collected other water measurements that can affect what fish are present.

• Salinity: how much salt was in the water. Some fish like salty water, some somewhat salted water (brackish), and some fresh!

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• Dissolved Oxygen (DO): how much oxygen is available for fish in the water to breathe. Healthy DO for most fish species is between 5-11ppm (or mg/l)

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• Water temperature – cooler water holds more DO

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• Environment – describe the sampling environment. Some sites are marshy, some have other plants.

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A YSI meter was used to measure these water quality indicators.

First Stop is in Yonkers, RM 18 �What is the Beczak site like?

Environment: The CURB (Beczak) site has a small marsh beside an opened beach with a sandy bottom. Some fish like marsh conditions – examples include the mummichog (also called mud minnows), flounder, and black drum.

�What are the water conditions at Yonkers, RM 18?

• If full ocean water is 35 ppt this water is about 1/4 the salinity of full ocean water.

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• Water in this salinity range is somewhat salty called brackish.

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• Remember the range of DO that fish like is 5-11 ppm. Is this enough to support a range of fish?

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• The temperature of the water at Beczak was a warm 81.5° F (27.5° C).

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LET’S SEE WHAT COMES UP IN THE NET!!!

Beczak Center in Yonkers

What’s in the net?

• What did we catch in this location aside from this blue crab?

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We caught a blue crab!

What’s in the net?

Remember we are sampling diversity (kinds of different fish) not abundance (total number of fish).

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How would our recording sheet be different if we wanted to collect abundance?

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What’s in the net?

Remember we are sampling diversity (kinds of different fish) not abundance (total number of fish).

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How would our recording sheet be different if we wanted to collect abundance?

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If we had recorded abundance what might we learn from that?

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If we had recorded size what might we learn from that?

What’s in the net?

Next we will look at each fish and their salinity preferences.

We labeled them by letter of salt preference:

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S=Salty

B=Brackish

F=Fresh

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With salinity at 8.1 ppt, what letter we would expect to see by every fish?

Let’s check.

White perch

Salinity preferences!

S=salty

B=brackish

F=fresh

Beczak Catch -2 slides

STOP HERE IF YOU PLAN TO HAVE YOUR STUDENTS COMPLETE THE FISH CHARTS ON THEIR OWN

Beczak in Yonkers Fish Catch�(salinity 8.1 ppt)

Sort Catch Based on Salinity

Drag each fish

species into

The circle with

the appropriate

Salinity preference, OR mark each fish with a color and match it to a place in the circle.

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What fits where?

Our next location is Croton Point Park RM 35. What is Croton Like?

Environment: Croton Point’s Mother’s Lap beach is an opened sandy beach with no marsh. The water is in a small bay that is protected from the faster moving river.

Our next location is Croton Point Park RM 35

• We were moving upriver away from the Atlantic Ocean.

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• Salinity here is about half that of Beczak. Water in this salinity range is still referred to as brackish, a mix of salty and fresh.

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• Check out the DO, is this enough to support a wide range of fish species?

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• The temperature of the water at Beczak was a warm 82.4° F (28° C).

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Young Striped Bass

CROTON PARK in Croton

What’s in the net in Croton?

Juvenile herring are sensitive to low levels of DO. DO levels here were a healthy 11 ppm.

The spottail shiner was first identified in the Hudson River and its Latin name is Notropis Hudsonius. Do you see the spot on his tail?

Does something surprise you?

Croton Catch

STOP HERE IF YOU PLAN TO HAVE YOUR STUDENTS COMPLETE THE FISH CHARTS ON THEIR OWN

Croton Fish Catch�(salinity 4.0 ppt)

Sort Catch Based on Salinity

What fits where?

Add each fish

species into

The circle with

the appropriate

salinity preference, OR mark each fish with a color and match it to a place in the circle.

Last Stop is Beacon, RM 61 �What is the Beacon site like?

Environment: Although there was no marsh, at the Beacon waterfront we found a huge plant bed of water chestnut plants (Trapa Natans), an invasive plant from Eurasia that makes dense plant mats on the surface and starves the water below of oxygen! This can make it hard for fish!

Beacon Waterfront

• This is just a trace amount of salt and the water is considered fresh water.

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• Note that the dissolved oxygen (DO) measured 3.3 ppm in the plant bed (!) and 5.6 ppm outside of the plant bed.

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• We decided not to fish in the plant bed. Why do you think we decided that?

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• The temperature of the water in the plant bed at Beacon was ~80° F (was 26.8° C) and ~81.5° F (27.5° C) outside the bed.

Invasive Water Chestnut plant.

Beacon Waterfront, Salinity 0.2 ppt

What did we catch in this location?

Recall we seined just OUTSIDE the plant bed, due to the low oxygen levels inside the bed which we felt would limit the number of fish present.

Is there a letter we would expect to find by every fish in this salinity?

What do we know about herring that might make it hard for them in this spot?

Beacon Sample

STOP HERE IF YOU PLAN TO HAVE YOUR STUDENTS COMPLETE THE FISH CHARTS ON THEIR OWN

Beacon Fish Catch�(salinity 0.2 ppt)

Sort Catch Based on Salinity

Add each fish

species into

The circle with

the appropriate

salinity preference, OR mark each fish with a color and match it to a place in the circle.

What fits where?

Think About the Fish Catch

• On the next page you will find a diagram with 3 circles. Each circle is posted with a different salinity, one for each salinity we sampled in this workshop. Beside the circles are the lists of species caught in each location.
• Can you find any species that could be caught in all 3 locations? What is your strategy to find this?
• One species was caught at Beczak and then again at Beacon but NOT at Croton.
• Can you find that species? What is your strategy?
• What do you think – does this species live in the Croton part of the river as well as the Beczak and Beacon areas?
• Why did you answer this way?

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Fish Catch Activity For All 3 Sites

Fish Catch Based on Salinity

Add each fish

species into

The circle with

the appropriate

salinity preference, OR mark each fish with a color and match it to a place in the circle.

Think About the Fish Catch �Answer & Explain

• What is one reason you think we found mummichogs at Beczak but nowhere else?
• What is one reason we might not have found herring in Beacon?
• We didn’t catch hogchokers in Croton yet they are listed as B,F. Does that mean there were no hogchokers in the river there?
• Why do you think freshwater fish might have been found where there was a little salt in the water?
• What surprises did you notice in the fish catches?
• We just sampled diversity at 3 sites in the Hudson River. If we had stayed just at Beczak what type of fish would we not have expected to find?

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A Day in the Life of the Hudson River �Fish Catch Activity

Discussion

• For a fish or species to live in a range of different salinities it has to be fairly adaptable. Can you name two fish species caught in this event that would seem to be fairly adaptable?
• You are working with data from a one day trip to the river. If we were to go to just Beczak in Yonkers to seine every day for a week in June would we:
• Expect to catch the exact same thing every day?
• Would we expect to catch a similar assortment of fish?
• Why did you answer this way?

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SUPPORTING SLIDES FOR STUDENTS TO COMPLETE�FOLLOW

Support Sheets: Beczak in Yonkers Fish Catch (salinity 8.1 ppt)

Sort Catch Based on Salinity

Match each fish into its salinity preference location on the 3 circles of Salty, Brackish & Fresh

Complete the chart using the information from Beczak fish salinity preferences

Croton Fish Catch�(salinity 4.0 ppt)

Sort Catch Based on Salinity

Match each fish into its salinity preference location on the 3 circles of Salty, Brackish & Fresh

Complete the chart using the information from Croton fish salinity preferences

Beacon Fish Catch�(salinity 0.2 ppt)

Sort Catch Based on Salinity

Match each fish into its salinity preference location on the 3 circles of Salty, Brackish & Fresh

Complete the chart using the information from Beacon fish salinity preferences

Use the resources & join us for A Day in the Life of the Hudson & Harbor”!�http://www.ldeo.columbia.edu/dayinthelife/