Stream life New Zealand Freshwater Crayfish - KOURA
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By Lachie Bowker, Class 5P
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Introduction I want to study Freshwater Crayfish known in Maori
as Koura. I want to study Freshwater Crayfish known in Maori as
Koura. I studied 3 streams. In all 3 streams Eels and other animals
such as snails were seen, lots of plants were seen but Koura were
not observed. I have caught Koura in Lake Taupo so I know some
exist. I studied 3 streams. In all 3 streams Eels and other animals
such as snails were seen, lots of plants were seen but Koura were
not observed. I have caught Koura in Lake Taupo so I know some
exist. Are they being hunted and eaten by predators in the streams
such as Eels? Is their food source running out? Are the streams no
longer a healthy place for them to live? Are they being hunted and
eaten by predators in the streams such as Eels? Is their food
source running out? Are the streams no longer a healthy place for
them to live?
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Questions What do they eat? Where do they go in the daytime?
Why arent they found in all streams? What predators do they have?
Where can they be found? Are they endangered?
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Scientific Name Kingdom: Animalia Kingdom: Animalia Phylum:
Arthropoda Phylum: Arthropoda Subphylum: Crustacea Subphylum:
Crustacea Class: Malacostracea Class: Malacostracea Order: Decapoda
Order: Decapoda Family: Parastacidae Family: Parastacidae Genus:
Paranephrops Genus: Paranephrops
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Description These are photos of some Koura. North Island Koura
and South Island are different sizes South Island koura grow to
80mm long North Island koura grow to 70mm long
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Food Chain Koura eat both animals and plants so are omnivores.
Koura eat both animals and plants so are omnivores. They eat snails
and insects. They eat snails and insects. They have lots of
enemies! They have lots of enemies! Their predators in water
include eels, perch, catfish, trout. Some of these arent native to
New Zealand. Their predators in water include eels, perch, catfish,
trout. Some of these arent native to New Zealand. They also have
lots of land based enemies which is strange because Koura live only
in water. They also have lots of land based enemies which is
strange because Koura live only in water.
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Food Chain Continued... Some of their land enemies are rats,
kingfishers, shags, scaup, stouts and kiwis. Some of their land
enemies are rats, kingfishers, shags, scaup, stouts and kiwis.
Humans also eat Koura so we are a predator! Humans also eat Koura
so we are a predator! So koura have enemies in water, on land and
even birds eat them. So koura have enemies in water, on land and
even birds eat them. Koura also eat their own species! This is
called cannibalism. Isnt it strange that they eat each other when
they have so many enemies? Koura also eat their own species! This
is called cannibalism. Isnt it strange that they eat each other
when they have so many enemies?
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Adaptive Features Antannae Antannae Koura use Antannae to feel
around the stream. They can also be used to poke enemies Eyes Eyes
The eyes of Koura are on short stems and can be moved around in all
directions Pincers Pincers Pincers are used to scare enemies and
grab their prey. If a Koura looses a pincer it will grow back
during their next molting cycle.
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Habitat Koura live in rocks, tree roots or in holes in the bank
during day time. Koura live in rocks, tree roots or in holes in the
bank during day time. Koura move to shallow water and on the
surface during periods of darkness. Koura move to shallow water and
on the surface during periods of darkness. They move to deeper
water during daylight hours. They move to deeper water during
daylight hours. In shallow water it would be easier for nocturnal
enemies to eat them such as kiwis and rats. In shallow water it
would be easier for nocturnal enemies to eat them such as kiwis and
rats.
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Is Their Population Shrinking? The department of conservation
lists Koura as a threatened specie as their population is
declining. The department of conservation lists Koura as a
threatened specie as their population is declining. Some people
think this is because the streams are now polluted more than they
used to be due to farming. Some people think this is because the
streams are now polluted more than they used to be due to farming.
Also there are lots of predators that eat Koura and some of these
are not native to New Zealand. Also there are lots of predators
that eat Koura and some of these are not native to New Zealand.
Trout eat a lot of Koura and Trout were brought to New Zealand by
the English. Trout eat a lot of Koura and Trout were brought to New
Zealand by the English. Eels and Trout eat a lot of the same food
as Koura so maybe there isnt enough food for them all. Eels and
Trout eat a lot of the same food as Koura so maybe there isnt
enough food for them all. Human Beings also catch and eat a lot of
Koura! Koura was like a treat for the Maoris. We caught and ate
some at Lake Taupo last year. Human Beings also catch and eat a lot
of Koura! Koura was like a treat for the Maoris. We caught and ate
some at Lake Taupo last year.
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Conclusion I started this project trying to answer some
questions about Koura. I went to 3 streams to look at the natural
habitat of Koura but I did not see any Koura in the streams. I
started this project trying to answer some questions about Koura. I
went to 3 streams to look at the natural habitat of Koura but I did
not see any Koura in the streams. After researching Koura on the
internet I found out that they are now listed as a threatened
specie by the department of conservation. This means they might one
day not exist as a specie. After researching Koura on the internet
I found out that they are now listed as a threatened specie by the
department of conservation. This means they might one day not exist
as a specie. The reasons for this include 1. some streams are now
polluted and arent healthy homes for Koura 2. The food they eat is
being eaten by other animals in streams like eels and trout. And 3.
Koura have lots and lots of enemies who like to eat them such as
eels, trout, kingfisher birds, HUMAN BEINGS and Kiwis. The reasons
for this include 1. some streams are now polluted and arent healthy
homes for Koura 2. The food they eat is being eaten by other
animals in streams like eels and trout. And 3. Koura have lots and
lots of enemies who like to eat them such as eels, trout,
kingfisher birds, HUMAN BEINGS and Kiwis.
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Video of Me and My brother investigating a stream Here is a
video of my brother Mason and I looking for Koura at Battle Hill
Park stream in Pauhatanui. We saw Eels, snails and lots of plants
and caught a baby Eel in our net but we didnt find at Koura. Here
is a video of my brother Mason and I looking for Koura at Battle
Hill Park stream in Pauhatanui. We saw Eels, snails and lots of
plants and caught a baby Eel in our net but we didnt find at
Koura.