You can join a national
programme to help restore the health of New Zealand's shellfish
beds. You'll swap information with other schools and send your
research findings to the Ministry of Fisheries.
Your research data
will not be lost, but will become part of a growing body of knowledge
about the health of New Zealand's Beaches. Your accomplishments
will become recorded as important scientific base-line data that
others will use for many years to come.
Your studies will
enable your local and regional councils and fisheries officers
to make important decisions about how to regulate the use of shellfish
and the beaches.
Cockles,
Pipis, Tuatua ,
Toheroa and other common shellfish on
beaches are important Indicator species that tell us about many
different aspects of the health of the beach. If the shellfish
beds are healthy, environmental conditions must be acceptable
for them. If they are not, your studies can lead to finding out
what is wrong and what needs to be done to return the beaches
to good health.
Cockles (Chione
stutchburyi) are the most common New Zealand beach shellfish.
They are most abundant on broad sandy mudflats extending off beaches
protected from strong wave action. In some places there are up
to 2000 cockles per square metre, or 20 million per hectare with
a weight of 160 tonnes. They are so abundant the surface is really
a pavement of cockles sprinkled with sand.
Shellfish have vanished from
many New Zealand beaches. Some of the possible causes for this
decline are:
----- Sediment eroded from farming or construction sites smothering
the shellfish.
----- Greedy overharvesting.
----- Pollution from stormwater run-off.
----- Toxic algal blooms.
Scientists are baffled
by the disappearance of shellfish from beaches where there seems
to be no reason for their loss. Because there has never been adequate
monitoring of the shellfish, the reasons for and the extent of
shellfish declines have not been documented.
Regular shellfish
sampling can provide interesting and valuable information that
can help prevent the loss of existing resources and possibly aid
in the restoration of depleted resources.
Beach Keeping is
a learning experience. Every beach has it's own special characteristics
so the activities must be considered a general guide. Each student
researcher must use imagination and resourcefulness to suit the
chosen beach.
The Maori protect
beach resources with Rahui, or temporary closures to harvesting.
Recently, the tangata whenua and others in communities near some
of Auckland's beaches have set up Rahui to help the shellfish
recover.
The legal daily bag
limit of cockles, pipi and tuatua is 150 shellfish per person.
Cockles are the favorite
food of the Oystercatchers (Torea). They use their strong orange-red
bills to spear open a cockle. They might gobble up 350 on a winter
day when they are cold and hungry. During the summer they feed
less, but can still put away 250 cockles a day.
Animals of the Rocky Shore of New Zealand by Margret
A. Leslie. Reed.
The Children's Guide to Collecting New Zealand Sea Shells
by Derick Lamb. The Bush Press.
Coasts and Us Teachers Education Kit. Northland
Regional Council
Common Seashells by J.R. Penniket. Reed Publishers
Native Animals of New Zealand by AWB Powell. Auckland
Institute and Museum.
Nature Watching at the Beach by John Walsby. Wilson
and Horton.
New Zealand Shells and Shellfish by Glen Pownall.
Dai Nipon Publishing.
New Zealand Shells by John Child. William Collins
(NZ).
Seashore Life of New Zealand by Erick Heath and
R.K. Dell. Reed Publishers
New Zealand Seashells in colour. Geoff Moon and
J.R. Penniket. 1970 Reed Publishers.
Shellfish of Soft Shores! Neighbourhood Biology Projects
for Teens. Mary Gardner YWCA at 203 Stuart St. Dunedin.
Fax 03 477 6783.
Protecting Sand Dunes Royal Forest and Bird Journal February 1996.
