Transcript Freshwater Organisms

Freshwater Animals
Freshwater macroinvertebrates
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are animals without backbones that live in or near the
bottom of freshwater ponds, lakes, streams, and rivers
for all or part of their life cycle.
They are very important indicators of the health of
these bodies of water, reflecting the quality of the
water and the conditions of the habitat.
Freshwater insects are a large group within the
macroinvertebrates found in bodies of freshwater.
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They make up 90% of the organisms living at the bottom
of a stream.
BENTHIC
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Organisms that live on the bottom are called
benthic.
Of the 2 million known insect species, there are
over 80,000 species that fall into the
macroinvertebrate category.
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Examples include mayflies, dragonflies, and beetles.
Other benthic macroinvertebrates that do not fall
into the insect group include crayfish, clams,
snails, worms, and leeches.
Categories of Organisms:
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All living organisms in
aquatic environments fall into
one of three categories:
Plankton – the drifters
(unicellular algae, jellyfish)
 Nekton – the free-swimmers
(fish)
 Benthos – the bottom
dwellers (crabs, muscles)
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Freshwater Animal
Groups
Macroinvertebrates
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General
Characteristics:
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No backbones
Live in or near the
bottom of ponds, lakes,
streams for all or part of
lifecycle
Many are indicators of the
health of the body of
water
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They make up 90% of
the benthic population in
freshwater ecosystems
Examples include:
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Aquatic insects
Leeches and worms
Clams
Crayfish (Crawfish)
Aquatic Adaptations
 Freshwater
macroinvertebrates are
usually grouped by three characteristics:
 how
they move,
 how they feed,
 and their tolerance to pollution (intolerant,
moderately tolerant, or tolerant)
How They Move
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Macroinvertebrates have to be able to move or
maintain their position in the water
How They Move
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Skaters – walk on the
surface
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Planktonic - Float
and/or swim in open
water to get food and
oxygen
Can dive and swim when
alarmed
Mosquito Larva
How They Move
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Divers - Swim by rowing
with hind legs in lakes
and pools
Predaceous Diving Beetle
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Swimmers – fish-like
swimming in streams and
lakes
Scavenger Beetle
How They Move
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Clingers - Attach to
rocks and such in fast
moving water
Adaptations include:
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long claws and flattened
bodies
Riffle Beetle
Water Penny –
found in riffles
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Sprawlers - Live on the
surface of floating
aquatic plants or fine
sediments
Adaptations include:
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Long legs
Deerfly Larva
How They Move
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Climbers - Live on
overhanging branches,
logs, etc.
Adaptations include:
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Structures for climbing
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Burrowers - Live under
fine sediment in pools of
streams and lakes
Adaptations include:
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Crayfish
Water Scorpion
Appendages or structures
for digging
Type
Description
Skaters
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Adapted for movement on the water’s surface
Scavenge on organisms caught in the surface film
Planktonic
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May float and swim in open water or float at the surface to get oxygen or food;
can dive when alarmed
Inhabit open water (limnetic zone) of lakes, ponds, and bogs (lentic systems)
Divers
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Can swim by rowing with the hind legs in lentic habitats and lotic pools
Swimmers
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Adapted for fish-like swimming in lotic and lentic habitats
Clingers
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Construct shelters, have long claws and flattened bodies for attaching to rock or
other surfaces in lotic riffles and wave-swept rocky littoral zones
Sprawlers
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Live on the surface of floating aquatic plants or fine sediments
Adaptations include long legs
Climbers
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Live on overhanging branches, logs, roots, or aquatic macrophytes
Adapted for climbing plants or debris
Burrowers
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Inhabit fine sediments of streams (pools) and lakes
Adapted for digging
How They Feed
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Shredders
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Eat live or dead aquatic
plant material
Chew, bore, or gouge
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Collector-gatherers
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Scud
Eat small bits of
decomposed organic
matter
Gather deposits from the
bottom
Midge Larva
How They Feed
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Collector-filterers
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Eat small bits of
decomposed organic
matter
Filter out of the water
Black Fly Larva
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Scrapers
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Eat algae, fungi, and other
things found attached to
plants or rocks
Scrape food from the
surface it is found on
Water Penny
How They Feed
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Piercers
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Eat live aquatic plants
Peirce into the plant and
suck fluids out
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Predators
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Eat live animals
Engulf whole animals, or
pierce into the animal and
suck fluids out
Water Boatmen
Giant Water Bug
Feeding
Group
Food Preference
Feeding Habits
Shredders
Live or dead aquatic plant material
Chew, bore, or gouge
Collectorgatherers
Small bits of decomposed organic
matter
Gather deposits from the
bottom
Collectorfilterers
Small bits of decomposed organic
matter
Filter matter out of the
water
Scrapers
Algae, diatoms, bacteria, and fungi
found attached to plants or rocks
Scrape food from the
surface it is found on
Piercers
Live aquatic plants
Pierce into the plant and
suck fluids out
Predators
Live animals
Engulf whole animals, or
pierce into the animal
and suck fluids out
Pollution Tolerance
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Macroinvertebrates are used as indicators of
pollution for many reasons:
Found in all aquatic habitat types
 Most live or stay over a small area
 Well documented species and lifecycles
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Tolerance values range from 0-10.
0 is least tolerant
 10 is most tolerant
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Pollution Tolerance Examples
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High Tolerance
Ex. Planaria
High numbers indicate
the water quality is very
poor
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Low Tolerance
Ex. Riffle Beetles
High numbers indicate
the water quality is very
good
Freshwater Fish
General Characteristics
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Ectothermic (coldblooded) – Their body
temperature fluctuates
with their surroundings
Have backbones
Have fins, scales, and
gills
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Habitats
Certain species of fish
are adapted for certain
water conditions.
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Some thrive in high
oxygen, and some thrive
in low oxygen
Some prefer open water,
and some prefer
backwater areas
Feeding Groups
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Fish in each of the feeding groups have
structures and adaptations to allow more
efficient feeding:
Ex.
Trophic Group
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Piscivores
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Predatory fish that eat
other fish
Have large eyes for better
sight
Well-developed lateral
line
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Invertivores
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Fish that eat invertebrates
(crayfish, mollusks,
insects, etc.)
Feed on bottom
Have fleshy lips or taste
buds on barbels to detect
prey
Ex.
Trophic Groups
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Omnivores
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Fish that eat any available
food
Feed on bottom
Have fleshy lips or taste
buds on barbels to detect
prey
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Herbivores
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Ex. Catfish
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Fish that eat plant
material
Use pharyngeal teeth for
crushing plant material
(pharyngeal teeth are a
modified gill arch in the
throat from crushing
plant material)
Ex. Minnow
Pollution Tolerance
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Aquatic macroinvertebrates are also put into
categories based on their tolerance to pollution.
Tolerance values range from 0 to 10 with 0 being the
least tolerant, and 10 the most tolerant.
Tolerance values are assigned to those organisms used
as pollution indicators.
Freshwater macroinvertebrates are
used as indicators of pollution for
many reasons:
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Important part of all aquatic ecosystems
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Found in all types of aquatic habitats
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Fairly easy to collect
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Have different levels of tolerance to an
environmental disturbance
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Most live or stay over a small area
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Life cycles of most groups are well documented
POLLUTION TOLERANCE
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Fish are good indicators of water quality for
many reasons:
Live in water for their entire life
Have long life spans
Easy to identify and collect
Communities are persistent and can recover
from natural disasters
Freshwater Fish
Families
General Characteristics
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Fish are cold-blooded animals, meaning their body
temperature changes with the temperature of their
surroundings.
They have backbones and live their entire lives in
water, breathing with gills and moving with fins.
There are 247 species of freshwater fish in Texas
alone.
Some of these species are able to live in brackish (partly
salty) water, such as in estuaries.
 All fish play an important role in the aquatic ecosystem
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Fish Habitat
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Each species of fish has its own distribution and
range of tolerance in which it can survive or
thrive.
The basic requirements for a fish’s survival
include prey, cover, suitable water temperature,
and dissolved oxygen levels.
Habitat Types
Fish Species
Streams
Riffles (high dissolved oxygen)
Darters, shiners
Pools (calm)
Sunfish, bass, catfish, suckers
Backwater areas (low dissolved
oxygen)
Gar, bowfin, pirate perch
Reservoirs
Open water
Shad, white bass, striped bass
Shorelines with aquatic vegetation Sunfish, bass, shiners
Quiet coves
Gar, suckers
Feeding Groups
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Fish feed at all levels of the food chain, from
bottom scavengers to top-level predators.
Fish can be categorized into groups based on
food preferences.
Fish in each of these groups have form and
structure adaptations to allow more efficient
feeding.
Trophic Group
Piscivores
(Predators)
Food Preferences
Fish that eat other fish
Invertivores Fish that eat invertebrates
(insects, worms,
crayfish, mollusks,
etc.)
Omnivores
Fish that eat any available
food
Herbivores
Fish that eat plant
material
Adaptations
Examples /
Adaptations
Large eyes for better
sight, welldeveloped lateral
line to detect
vibrations of prey
in the water
Large and small
mouth
bass,Flathead
catfish, Gar,
crappie
Feed on bottom –
fleshy lips
(suckers) or taste
buds on their
barbels (catfish) to
detect prey
Blue sucker, red
shiner, bluegill,
longear sunfish
Shad, carp,
channel catfish
Use pharyngeal teeth (a Grass carp,
modified gill arch
stoneroller
in the throat) for
crushing plant
material
Fish Structures
Gar Family
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Bodies are covered with diamond shaped plate
scales
Designed for backwater areas
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Breathe with gills or lung-like air bladder
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The air bladder is connected to the throat so it can
breathe air.
Spotted Gar
Long-nose Gar
Alligator Gar
Herring Family
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Bright, silvery, and flatsided
Feed on plankton
Transparent eyelids
Important for food –
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Fish meal in livestock
feed and pet food
Carp and Minnow Family
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Largest freshwater fish family
Can live almost anywhere and eat anything
Keen sense of hearing
Series of small bones connect the inner ear to the
swim bladder
 The swim bladder picks up vibrations in the water
and sends them to the inner ear
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Red Shiner
Invasive Carp
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Grass carp were brought from Asia into North
America and Europe to control aquatic
vegetation
They became invasive, taking over waterways
and eating up all the vegetation, and are
regulated by Texas Parks and Wildlife
Grass Carp
Sucker Family
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Have a toothless and sucker-like mouth with
thick lips
Have pharyngeal teeth
Mostly omnivorous, feeding from the bottom
North American Catfish
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Easily recognizable by scaleless body, broad flat
head, and barbels
Barbels posses taste buds which help them to
locate and taste food (especially in murky water
and at night)
Possess venomous spines at dorsal and pectoral
fins
Blue Catfish
Channel Catfish
Flathead Catfish
Pirate Perch
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The position of the anus is behind the mouth
Tolerant of high water temperatures and low
dissolved oxygen
Live mostly in swamps and backwaters
Topminnow Family
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Also called “killfish”
Spend most of their time at the water surface
Feed with upturned mouths and flattened heads
Livebearer Family
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The females give birth to live young
Western Mosquitofish
Sailfin Molly
Pupfish Family
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Very tolerant of high temperatures and low
dissolved oxygen
The most heat tolerant of all fishes
Feed mostly on insects, snails, and crustaceans
Most are threatened or endangered due to
habitat loss or hybridization from non-native
species
Sheepshead Minnow
Temperate Bass Family
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White and yellow bass, white perch and striped
bass (hybrid)
Striped bass has been introduced into inland
reservoirs and lakes
Usually travel in schools in open water (pelagic)
White Bass
Yellow Bass
Striped Bass
Sunfish Family
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Includes sunfish, crappie, and large-mouthed
bass
Most are sedentary and hide under cover
Green Sunfish
Bluegill
Largemouth bass
White Crappie
Perch Family
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All members are predatory
Darters are adapted for life in fast-flowing
streams
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Spend most of their time in between rocks, waiting
for prey
Orange-throat Darter
Drum and Croaker Family
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Only one member lives strictly in
freshwater…the freshwater drum
Makes a grunting sound by special muscles and
tendons connected to its swim bladder
Feed mostly on the bottom, grinding their food
with pharyngeal teeth
Freshwater Drum
Cichlid Family
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Native to Africa, Central and South America
One species found in the Rio Grande River
Popular aquarium fish because of bright colors
Predatory, and some are considered invasive
because they compete with our native basses
and sunfish for food
Rio Grande Cichlid
Common Freshwater Reptiles
Common Freshwater Reptiles
Characteristics
 Reptiles are air-breathing vertebrates that are
cold-blooded, meaning their body temperature
is determined by their surroundings. Reptiles
control their body temperature by moving to
warmer or cooler areas as necessary.
There are many groups of reptiles
found in freshwater ecosystems:
Crocodiles and Alligators
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There are 21 know species of alligators, crocodiles,
and caimans in the world, but only two are native to
the United States—the American alligator, and the
American crocodile.
The American alligator (Alligator mississippiensis) is
native to Texas, but the crocodile is not.
The American crocodile is native to the southernmost tip of Florida.
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The American alligator is the largest reptile in North America.
It can grow to more than 19 feet long.
They inhabit the eastern part of Texas, and most of the Gulf
of Mexico coast.
They are found in rivers, swamps, lakes, and bayous, and can
tolerate the brackish water of coastal marshes.
During the coldest months and in dry seasons, they dig deep
holes in muddy banks, where they hibernate.
They are carnivorous predators that feed mostly on fish,
snakes, turtles, small mammals, and waterfowl.
The alligator can chew underwater, but must surface to
swallow.
When breeding, the female builds a large mound of mud and
leaves, and drops up to 60 hard-shelled eggs into the center.
The female stays to protect the nest for the 9 weeks it takes
for them to hatch.
Turtles
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Turtles are the oldest living reptiles.
Freshwater turtles have a toothless, horny beak and a shell
of bony dermal plates, usually covered with horny shields,
enclosing a soft body.
The head, limbs, and tail may be drawn into the shell when
necessary.
Turtles have scaly skin and are often seed basking on rocks
and logs.
They lay eggs in cavities dug out by the female.
Texas is home to 35 species, with about 240 found
worldwide.
There are 4 families of Turtles found in Texas: Snapping
turtles, soft-shelled turtles, box and water turtles, and musk
and mud turtles
Snakes
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Snakes are a limbless, scaled reptile with a long
tapering body.
Over 2300 species of snakes are known
worldwide.
They live all over the world, but are absent
from many islands, such as Ireland, New
Zealand, and Hawaii.
There are two families of snakes in Texas:
 vipers (poisonous) and Colubrids
(nonpoisonous)
Freshwater
Amphibians
General Characteristics
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Amphibians have many characteristics that are in between fish
and reptiles.
The work “amphibian” means “living a double life”.
Larvae of amphibians have gills and live in water, while adults
breathe air through either their skin or lungs.
Amphibians, like reptiles, are vertebrates that are coldblooded.
They have moist, glandular skin and their toes lack claws.
They lay gelatinous-covered eggs in moist areas.
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Groups include frogs, toads, salamanders, and newts.
Frogs have smooth skin, webbed feet, no tail, and have long
legs for leaping, while toads have warty skin and short legs for
hopping.
They both feed on insects, crayfish, minnows, and on almost
anything smaller than themselves.
Freshwater Aquatic
Plants
General Characteristics
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Aquatic plants have adapted to living in a variety
of water conditions ranging from swift-flowing
to stagnant.
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are an important part of an aquatic ecosystem.
Plants affect water quality by adding oxygen to
the water column and by stabilizing bottom
sediments and shorelines to reduce turbidity.
 They also provide protection, feeding areas, and
spawning areas for fish, invertebrates, &
waterfowl.
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Groups – Aquatic plants are grouped in three
categories, according to their growth habits
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Floating plants – plants that float freely on the
surface and plants that are rooted on the bottom
with their leaves floating on the surface
Emergent plants – plants that are rooted to the
bottom and grow above the water along
shorelines and in shallow water areas.
Submerged plants – plants that are generally
rooted at the bottom and are completely
underwater, except for seed heads or flowers.
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Nearly all aquatic plants live in the littoral zone (nearshore area.)
The extent to which they move away from shore
depends on the depth that light penetrates into the
water column.
In large lakes, plants may inhabit only shallow nearshore areas.
In shallow lakes, ponds, and slower-moving streams
and rivers, aquatic plants may inhabit the entire water
body.
Free-floating plants cause problems by covering a
water body and reducing the amount of light available
to other aquatic organisms.
Nonnative and Invasive Species
 Most
Texas streams or reservoirs are home
to at least one nonnative species (those
species that enter an ecosystem beyond
their historic ranges).
 In Texas, at least 35 nonnative species have
become established in aquatic habitats.
How Did They Get Here?
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Increasing local food supplies
Authorized enhancement of sport and commercial fisheries
Manipulating aquatic ecosystems to control pests or nuisance
plants
Improving the appearance of an area
Unauthorized stocking of ponds or waterways by fishermen
Hitchhiking on boats (snails, plants)
Releases from personal aquariums (plectosimus)
Escape from aquaculture facilities
Canal systems
Angler bait buckets
Negative Impacts of Non-native
species
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Prey on native fish
Altering established aquatic food webs
Introducing new parasites or diseases
Altering habitats
Damaging the genetic integrity of native species by
hybridization
Out-competing native species for resources
Clogging irrigation canals
Endangering commercial and recreational fishing due
to lower numbers of native species