GAMING

Fish & Game outlines strong case for swan drive on Tauranga Harbour

Monday 28 May 2012, 12:17PM
By Fish & Game NZ
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TAURANGA

Fish & Game Eastern Region says there are some strong environmental, public safety and other factors which make a strong case for requiring the reduction of black swan numbers on Tauranga Harbour.

The black swan population in the Bay of Plenty area, and on the harbour in particular, have been increasing over the past decade.

The Eastern Fish and Game Council, which manages sports fish and game birds in this region, has a responsibility to keep populations to a manageable size so they do not have a detrimental effect on other natural resources or users of the harbour, says manager Rob Pitkethley.

“We acknowledge that some people are uncomfortable with these hunts, but we have a responsibility to act on the concerns of harbour-side property owners and public users, farmers whose crops are damaged, and airport officials who at times have voiced concern that the birds pose a threat to air traffic safety.

“We also have a duty to our game bird licence holders who are hunting these birds quite legally, as black swans are on the game bird schedule. This group of hunters operates within all the rules and regulations, and they are expected to adhere to our game bird hunting code of conduct.”

Mr Pitkethley says that some local residents concerned at the fouling of harbour sandbars and beaches, are also keen to see limits on swan numbers. 

There is strong scientific evidence of the environmental damage they can do, he adds, including a study (see attached) which shows black swan populations over 5000 pose a threat to seagrass meadows, which are known to be important nursery habitats for juvenile snapper.

There is also research to show that while the black swans are a native species, they can withstand moderate harvest measures, Mr Pitkethley says.

Fish & Game’s involvement is limited to issuing a permit to disturb the birds, which is usully outside of game bird hunting regulation.

“The permit we issue, which allows the swan population reduction, is all about authorising them to proceed in a safe and effective manner. The permit allows the birds to be guided by boat to an area where they can be harvested with no risk to members of the public.

“There are limits on the number of swans allowed to be harvested by each hunter to ensure the population remains at a sustainable level.”

Mr Pitkethley says that it should also be noted that no ratepayer or taxpayer money is spent on the hunt – it is all funded by the individual hunters taking part. Fish & Game works closely with the Department of Conservation to maintain the population levels of the black swan.

FURTHER INFORMATION

Note to reporters : The swan hunt is expected to take place off Beach Road Katikati boat ramp at about 1pm, Sunday ,May  27th 2012

Black swan hunt - Tauranga Harbour

There is no ‘official’ cull of black swan on Tauranga Harbour by Fish & Game or Department of Conservation.

  • A group of hunters, as part of the normal game bird hunting season, hold a coordinated hunt run within all the normal game bird rules and regulations.
  • Fish & Game issue a permit to disturb swan to a group of non-shooters working with the hunters. The permit allows them to chase swan in a motorised craft towards the hunters. (The reasons for issuing the permit are detailed below).
  • The birds are moved from populated areas prior to the hunt to ensure there’s no risk to the general public.
  • Members of the public have complained that swan numbers on Tauranga Harbour are too high.  Their complaints mainly centre on the amount of swan faeces on beaches and mud flats.
  • Tauranga Airport has at times raised concerns with Fish & Game regarding the number of swan near the runway.  Increasing swan numbers could pose an aviation hazard.
  • Swan numbers – which have risen to over 5000 on the harbour – could threaten seagrass meadows (Dos Santos et al., 2012).  This recent research has calculated that the swan population on Tauranga Harbour at a minimum of between 4,600 - 7,400 birds, may remove more than 30% of the Zostera biomass annually – a critical threshold where seagrass meadows may not fully recover.
  • No taxpayer’s money is spent on the hunt.  It is funded solely by the individual hunters taking part.
  • Swan is a native species (Worthy and Holdaway, 2002) but one that can withstand a moderate harvest.  New Zealand has a wide and historic acceptance that many of our native wildlife and fish species (particularly inshore fisheries) can be harvested.

 

BACKGROUND:

  • Black swan are listed as a game bird under Schedule 3 of the Wildlife Act, 1953. They may be hunted subject the Minister’s (Conservation) notification.
  • The Eastern Fish & Game Region is divided into four Game bird Management Units; established criteria to harvest this species is based on a minimum population size in each Management unit.  The population in each unit must exceed 1000 black swan before an open season is declared by the Minister.
  • Annual aerial counts of black swan on Tauranga Harbour have been conducted since the late 1970s.  The population has gone from a low of 851 in 1980, to a high in 2010 of 5010.
  • Band recovery suggests that the Rotorua and Waikato lakes swan populations may disperse to Tauranga Harbour (Williams, 1977, Williams, 1981), and probably vice versa.  Therefore the swan population in the Rotorua lakes and adjacent estuaries and wetlands are treated as one management unit (Management Unit A1).  In 2012 this population count was more than 6000 birds.
  • Following the collapse of macrophyte beds in the Waikato lakes, it appears that many swan may have moved to either Kawhia Harbour or Tauranga Harbour.
  • By 1996, one third of the Seagrass (Zostera muelleri) meadows that were present in Tauranga Harbour in 1959 had disappeared (Park 1999; cited in Dos Santos et al. 2012).
  • Zostera is important to a wide assortment of species (Dos Santos, 2011) including acting as a nursery area for many marine fish species such as snapper (for example see http://www.stuff.co.nz/taranaki-daily-news/news/4598947/Fish-to-get-designer-nurseries).
  • Swan could constitute a threat to seagrass meadows under high grazing pressure (Dos Santos et al., 2012). This research calculated that 4,630 to 7,400 black swan on Tauranga Harbour may remove more than 30% of the Zostera biomass annually - the critical threshold where the seagrass meadows may not fully recover.
  • Since 2010, the January aerial counts of black swan on Tauranga Harbour have exceeded 4,630.
  • Fish & Game has a statutory responsibility under its Eastern Region Sports Fish and Game Management Plan to ensure game birds do not have an adverse effect on natural resources and other users of the environment (see Appendix 1).
  • To fulfil this requirement to mitigate any adverse effects swan may have, particularly in relation to the impacts on Zostera and the airport, Fish & Game assists the hunters, facilitating a permit to chase swan from a motorised craft.
  • Fish & Game have talked to the hunters prior to the hunt to ensure procedures are in place to deal with any birds that are not killed outright, to ensure that any wounded birds are dispatched as quickly and humanely as possible.  In the Game Bird Hunting Guide distributed to all licence holders there is a Code of Conduct that promotes taking all reasonable steps to quickly and humanely dispatch wounded game.
  • Other methods of controlling swan numbers such as egg pricking are not suitable for the Tauranga population as they do not breed there.

Appendix 1

Extract from the Eastern Region, Sports Fish and Game Bird Management Plan

1.4.2(c)    To respond where there are significant adverse effects of game birds on natural resources and other users of the environment.  Significance will be assessed on the basis of:

•          number of birds present

•          recreational and ecological significance of the game bird population involved

•          value of resource affected

•          extent of impact of birds on the crop involved

•          whether there is a significant effect on indigenous flora or fauna, where Department of Conservation will be consulted as to the effects