Natures Vampire: The Lamprey
By Rachel, Paige and Jenn
Life Process
Spawning Phase: Spring -early summer
Once sea lampreys have reached sexual maturity, they stop feeding
and begin to congregate off the mouths of streams and rivers in
preparation for spawning.
Lampreys construct crescent-shaped nests of small stones and
gravel. The female may lay 30,000 to 100,000 eggs. After spawning,
the adults die.
Larval Phase:
Most fertilized eggs settle in amongst the gravel of the nest and hatch
in a few weeks. The young larvae emerge from the nest and then
burrow into the stream's sand and silt bottom. The larvae feed on
algae, detritus, and various small organisms.
Transforming Phase: Late summer- early fall
After three or more years as harmless larvae, they undergo a change
called transformation, where they develop eyes and a sucker-like
mouth with sharp teeth.
Parasitic Phase:
Lampreys typically move into the sea to begin a parasitic life, attaching to
a fish by their mouths and feeding on the blood and tissues of the host
They can spend 12-18 months in the parasitic phase until they are
sexually mature enough to reproduce.
Diet/Nutrition
Larva Phase: algae, detritus and various small
organisms
Parasitic Phase: feed off host (fish)
One lamprey can consume over 40 pounds of fish in
its lifetime
Spawning phase: No feeding
Specialized Systems
•
•
•
•
•
•
Digestive
Circulatory
Nervous
Excretory
Reproductive
Motile? yes
Digestive System
Mouth →Pharynx→ Esophagus → Intestines
• Alimentary canal: runs from mouth to the anus.
• No stomach
• Intestines: The site of the emulsification, digestion and
absorption of nutrients.
• The latter portion of the intestine digests bacteria,
reabsorbs water and forms feces.
• The last section of the intestine narrows to form an exit
called the anus. The resulting solid wastes leave the body
at this point.
Digestive System
Nervous system
• Lamprey's have a primitive vertebrate nervous system,
meaning the brain structure is fairly simple compared to
other vertebrate animals
• System consists of the brain and a hollow spinal cord
– Situated above the alimentary canal.
– Vertebrate nerve cord and brain contain a cerebrospinal fluid
which contains mineral salts and traces of protein and sugar. The
fluid helps to support the nervous tissue and probably plays
some part in its nutrition.
• The nerve fibers are not covered by the myelin sheath (a
fatty insulating layer) found in all higher vertebrates
– Therefore nervous conduction is slow. The complex nervous
connections found in higher forms are impossible in these early
vertebrates.
Nervous System
Lamprey Brain
Circulatory/Respiratory Systems
• Blood flows through a series of vessels to supply oxygen and
nutrients to the body and to remove carbon dioxide and other
wastes.
– Arteries and arterioles carry blood away from the heart
– Veins and venules carry blood back towards the heart
– Capillaries are the smallest vessels where the gases are exchanged
with the cells of the body
•
A lamprey “breathes” by extracting the oxygen present in the
water in which it lives
• Water: mouth →pharynx → respiratory tube
• Within the respiratory tube are seven gill pouches, each containing
the finer feather-like gill lamellae. The gill lamellae increase the
surface area of the respiratory structures and contain the small
capillary beds that extract oxygen.
Circulatory/Respiratory Systems
• Problem: When a lamprey is feeding and
attached to a fish the mouth serves as an
attachment function, it is no longer available
for use in respiration.
• Solution: Water can be drawn directly into the
respiratory tube through the external gill slits.
Muscular contractions change the volume of
the respiratory tube and thus control the
movement of water over the gill lamellae.
Circulatory/Respiratory Systems
Lamprey larva
Excretory System
• Kidney: filters out waste from the blood
– Ions, water and other nitrogenous wastes
– Responsible for maintaining osmoregulation
• The balance between the salts in the body and the salts
in the environment.
• Freshwater: kidneys excrete extremely dilute urine to
maintain the ionic balance in the body.
• Salt water: kidneys excretes a highly concentrated
urine. Lampreys rely on the gills to rid the body of
excess salt.
Reproductive System
• In late winter, the lamprey's sexual
reproductive system grows and their
intestines shrink
• Therefore, they don't eat in the winter but live
off stored fat
Female Reproductive System
Larva Body Plan
Rudimentary
eyes
toothless
Body Plan
Range from 15 to 100 centimeters (6 to 40 inches) long
Lack bones, jaws, scales and paired fins
The mouth is
a round,
sucking
opening with
teeth
2 eyes
Symmetry: bilateral
1 nostril on
top of head
Dorsal fin
7 gill openings on
each side of the body
Tail fin
Internal Plan
Ecological Niche- Chordata
• Environments:
• The sea lamprey is indigenous to the
Atlantic and Pacific Oceans and returns to
freshwater tributaries to spawn.
• Found in the Great Lakes
• Role in environment: parasite, vertebrae
• Relationships: Parasitic/dependent upon host
Challenge: Considered a pest
Lamprey’s can kill large
numbers of predatory sport
fish. People notice the lack
of large fish and the scars on
others. The lamprey invasion
made it hard on the people
who fished the Great Lakes
to make a living.
Evolutionary History
• Of the 46,000 known species of
vertebrates, lampreys and hagfish are
the only surviving jawless vertebrates.
• Lampreys are the most “primitive” of
the vertebrates, meaning that they are
the least altered from the first
vertebrates.
– They lack jaws, paired pectoral and pelvic
fins, and scales.
• “Apart from being the oldest fossil
lamprey yet discovered, [these fossils]
show that lampreys have been parasitic
for at least 360 million years”. - Dr.
Bruce Rubidge
Lamprey vs. Hagfish
Bibliography
• http://www.truaxbiology.com/sully/Sully_Bio/
Chordates_files/Sea%20Lamprey.pdf
• http://www.daviddarling.info/encyclopedia/V/
vertebrate_nervous_system.html
• http://www.allsands.com/science/animals/sea
lampreysgui_skg_gn.htm