Fishing During the
Blue Water Marine Research Ltd
23 August 2003
not close the snapper fishery during the spawning season?
Then there would be more
fish able to spawn, more eggs in the water and more fish in the
The simple answer
is that more eggs does not mean more fish will survive from that
We are not talking sheep here. There is no lambing percentage
where the number of offspring is directly related to the number
of breeding females.
Female snapper, like most
fish, produce 100,000s even millions of eggs each, but the mortality
of eggs and juveniles is extremely high. Almost all of them will
die. However in warm years survival can be 10 times, even 100 times
higher than cold years. Fish have developed a breeding strategy
that is more dependant on environmental conditions than the number
of breeding adults. This is to take advantage of good years. It’s
a gamble like rolls of the fruit machine. Some years they hit the
jackpot, when all the favourable factors line up. Like:
Plenty of Food
Even so, if too many young
survive, come winter there will be much less food and too many mouths
to feed. Many will starve and mortality could skyrocket.
it matter when you fish?
What is the difference if you catch a female snapper during spawning
or if you catch a snapper a week before spawning? Surely it will
have the same effect. That fish wont spawn. What about 6 months
before spawning? You still remove it from the breeding population.
What is important is that each year the reproductive potential of
the population is sufficient to take advantage of the good seasons.
Some very successful snapper spawning seasons have occurred in the
1990’s at the current stock size. 1991, 1995 and 1996 were
all strong year classes.
Snapper do not spawn over
a set period of time, spawning is dependant on things like, water
temperature. Also fish may spawn several times during the spring
/summer period. It would be impossible to forecast what sort of
summer we are expecting in order to forecast when to allow fishing
to avoid catching spawning fish.
You can convince some people that there is no biological reason
that spawning success will be improved by a ban on fishing during
the snapper-spawning season. Often their real concern will soon
“But they take too
many” they say. Snapper school season arrives and those commercial
fishers, or those guys down the road, or those charter boats, they
catch heaps “They are going to wreck it”. But these
are management issues – more about the sustainable yield,
quota and bag limits – not issues about spawning success.
A lot of time and money
(mostly funded by cost recovery from commercial fishers) is spent
on making sure that snapper is being fished sustainably. But it
is a big fishery in New Zealand; about 13,000 tonnes a year are
landed nationwide. That’s a lot of fish. Probably 12 million
snapper taken per year and about half of those are by recreational
fishers. Still the fishing has been very good over the past summer
of 2002/03 in the Hauraki Gulf but not so consistent in Northland
or Bay of Plenty. Current stock assessment is that the main fisheries
A ban on fishing for snapper during
the spawning season would be a disaster. How would you manage it?
For example, where could you fish in the Hauraki Gulf and avoid
catching snapper in spring? You would catch them just about everywhere.
Many fish could survive catch and release but you would also have
to throw back the hook damaged ones to die. Enforcement on the boat
ramps and marinas would be a nightmare. The only way it could work
would be to close the Gulf to all fishing in spring. Imagine the
reaction from the fishing industry, their lawyers, and the Treaty
of Waitangi Fisheries commission. And what about all the recreational
groups, fighting hard to defend our right to fish in the sea? They
would most likely view this as a huge loss to the public access
right. If the same amount of fish were taken out of the fishery
over the whole year then there would not seem to be any benefit
to outweigh the huge disruption of closing areas during the spawning
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