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Prawns
and shrimps
updated
Apr 2020
if you
learn only 3 things about them ...
 There is no scientific difference between shrimps and
prawns.
Many are well camouflaged, others are buried in the sand,
yet others transparent.
Some
live on other animals such as sea anemones and hard corals. |
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Where
seen? Among our favourite seafood, prawns and shrimps come in various sizes
and colours. Close observation is needed to appreciate their delicate
patterns and colours, and amusing behaviour. Prawns and shrimps are
common on almost every shore. However, they are difficult to spot
as they are often small, and hide in burrows or just beneath the sand.
Even those in plain sight disappear from view as many are nearly transparent.
They are adapted for bottom dwelling.
What are prawns and shrimps? Prawns and shrimps are crustaceans that belong to various groups in the larger Order Decapoda.
There are no clear scientific differences between prawns and shrimps.
Generally, smaller ones are called shrimps while larger ones prawns.
Features: Usually less than 5cm
long. Unlike crabs which have stiff shells to protect their abdomen,
a shrimp has a thin, flexible shell over a long abdomen that ends
in a broad fan-like tail. A quick contraction of the muscular abdomens
propels the shrimp backwards. To swim slowly, the shrimp paddles with
the small swimmeretes (pleopods) under the abdomen.
Many shrimps are transparent, blending in wherever they are. Some
may be red, a colour that is hard to distinguish in the dark or in
deeper water.
What do they eat? Larger shrimps
are mostly scavengers or eat small plants and animals. Smaller ones
feed on plankton and algae. |
How do they mate? Shrimps have
separate genders. To mate, a male inserts his sperm packet into a
special receptacle in the female. Fertilisation, however, is external.
The female releases the sperms from the packet together with her eggs.
A female prawn produces a huge number of eggs, as much as one million
in one spawning! Some may carry their eggs under their tails.
Prawn
babies: Like many marine creatures, shrimps undergo
metamorphosis. That is, they change their shape as they develop
through their life cycle. Most adult shrimps migrate to deeper
waters to breed and release their eggs. Eggs usually hatch quickly,
within a day or so.
After hatching from the egg, the larvae look nothing like the
adults! These larvae drift with the plankton, changing shape
as they develop further. Eventually, they look more shrimp-like
and migrate back to shallow waters. Here they develop into mature
adults before starting the cycle all over again. |
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Role in the habitat: Shrimps are
numerous and eaten by a wide variety of larger creatures. In coral
reefs, some species of shrimps act as cleaners, picking parasites
and dead skin off fishes. The fish 'clients' allow the cleaner shrimps
to do their job without eating them. These cleaners are often brightly
marked. Some shrimps also live with other sea creatures. Anemone
shrimps, for example, frolick happily among the tentacles of a
sea anemone that would kill and eat other creatures.
Human uses: Shrimps and prawns
are relished food by people everywhere. In Asia, shrimps are eaten in many
ways. Besides the usual dishes made from whole shrimps, they may also
be dried, or made into paste ('belachan') or mixtures ('cincaluk').
Tiny shrimps are used as condiments, and shrimps flavour crackers,
balls and other delicacies. While traditional farming and harvesting
methods are sustainable, large-scale commercial prawn farms and prawn
trawling are more destructive and unsustainable. More
about prawn farming and trawling.
Status
and threats: Some of our shrimps and prawns are listed
among the threatened animals of Singapore. However, like other creatures
of the intertidal zone, they are all affected by human activities
such as reclamation and pollution. Trampling by careless visitors
and over-collection can also have an impact on local populations. |
| Some Prawns and Shrimps on Singapore shores |
Marine
shrimps and prawns recorded for Singapore
from Wee Y.C. and
Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore.
in
red are those listed among the threatened animals of Singapore
from Davison, G.W. H. and P. K. L. Ng and Ho Hua Chew, 2008. The
Singapore Red Data Book: Threatened plants and animals of Singapore.
*from Tan, Leo W. H. & Ng, Peter K. L., 1988, A Guide to Seashore
Life
**from Lim, S., P. Ng, L. Tan, & W. Y. Chin, 1994. Rhythm of
the Sea: The Life and Times of Labrador Beach.
+from our observation.
^from WORMS
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Prawns
and shrimps seen awaiting identification
Species
are difficult to positively identify without close examination
of small features. On this website, they are grouped by external
features for convenience of display. |
Infraorder
Caridea
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Family
Atyidae (freshwater shrimps)
Most
members of this family are freshwater shrimps |
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Caridina
gracilirostris
Caridina peninsularis
Caridina propinqua (Mangrove
hairy-handed prawn)
Caridina tonkinensis
Caridina weberi sumtrensis
Caridina temasek (Temasek
shrimp) (EN: Endangered) |
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Family Hippolytidae (humpbacked shrimps, cleaner shrimps, saron shrimps)
with list of species recorded for Singapore |
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Family
Palaemonidae (glass shrimps and commensal shrimps)
with list of species recorded for Singapore |
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Family
Pandalidae (marine carid shrimps) |
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Chorotocella gracilis
Heterocarpoides levicarina=^Procletes levicarina |
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*Acetes sp. (Belachan shrimp)
Acetes japonicus |
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Chlorotocoides
spinicauda |
Infraorder Stenopodidea
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Family
Stenopodidae (boxer shrimps) |
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Links
- Belachan
Shrimp (Family Sergestidae), Glass
Shrimp (Family Palaemonidae), prawns
Tan, Leo W. H. & Ng, Peter K. L., 1988, A
Guide to Seashore Life. The Singapore Science Centre,
Singapore. 160 pp.
- Marine
prawns (Penaeus and Metapenaeus spp.), Estuarine
prawn (Macrobrachium equidens), Mangrove
hairy-handed prawn (Caridina propinqua) Ng, Peter K.
L. & N. Sivasothi, 1999. A
Guide to the Mangroves of Singapore II (Animal Diversity).
Singapore Science Centre. 168 pp.
References
- Wee Y.C.
and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore.
National Council on the Environment. 163pp.
- Davison,
G.W. H. and P. K. L. Ng and Ho Hua Chew, 2008. The Singapore
Red Data Book: Threatened plants and animals of Singapore.
Nature Society (Singapore). 285 pp.
- Ong, Jin
Eong & Gong, Wooi Khoon (eds.), 2001. The
Encyclopedia of Malaysia (Vol. 6): The Seas
Didier Millet, Malaysia. 144 pp.
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