Record oystercatcher chick at Tahuna Torea

This summer Tōrea pango / Variable Oystercatcher have nested for the first time at Tahuna Torea Nature Reserve (written records began in the 1970’s). Its also the first time any bird has nested on the man-made shorebird roosts (or islands) in the lagoon. Tōrea Pango are recovering from being threatened with extinction and are one of the most endangered breeding birds in the Eastern Songbird Project area. The nearest breeding area is Motukorea / Browns Island which is a population sink for the species. The reserves name ‘torea’ does not come from this species but the South Island Pied Oystercatcher which once gathered here in great numbers.

The two egg nest was laid days after I trimmed the vegetation on Kuaka Island mid November 2023 as part of a roost restoration project. A team of local bird watchers kept a close eye on the nest. The mud in the lagoon keeps the cats out, but not the rats, the trapping team stepped up efforts and rats stopped turning up on the trail camera. One of the eggs was not fertile but the other one was and the bird watching team was thrilled when a chick hatched just in time for Christmas.

Tōrea Pango Chick on Kuaka Island. Photo by Shaun Lee.

The nest would not likely have survived a kiteboarding event in the lagoon. Thanks to the kiteboarders for volunteering to stop kiting in the lagoon at high tide. If you do see anyone kiting in the lagoon phone me 021 555 425 and I’ll have a chat to them.

Tōrea pango whanau at Cable Beacon Point. Photo by Basil Avery.

It was interesting that after nesting on Kuaka Island where I had trimmed vegetation and where a small amount of mangroves have been removed (not the majority) the parents then took the chick 400 m southeast to Cable Beacon Point. New mangrove stumps here were used by the chick to hide. I put up a sign and the bird watchers were on high alert for a few weeks until the chick fledged. The Tōrea pango whanau have stayed in the area which is a great endorsement of the reserve from our feathered friends and a huge win for our shorebird habitat restoration efforts.

The fledged Tōrea pango chick. Photo by Shaun Lee.

The unmanaged fisheries of the Hauraki Gulf Marine Park

In New Zealand, we have 75 fish populations that are supposed to be managed sustainably. The main way we do this is by setting limits on how many fish can be caught, known as the Total Allowable Catch (TAC). We don’t keep regular track of the fish caught by recreational and cultural fishers. The only annual numbers are for commercial fishing, which has a limit called the Total Allowable Commercial Catch (TACC).

What’s puzzling is that for many fish populations, the TACC is set way higher than what’s actually being caught, and it’s been like that for years without any change. To me, this means these fish aren’t really being managed at all. Of the 75 in Aotearoa there are 16 fish populations in the Gulf that stand out as ‘unmanaged’ due to their TACC being significantly higher than the actual catches.

I had high hopes for the new Fisheries Management Plan for the Gulf, thinking it might sort out these unmanaged populations. I tried to get some answers by writing to the minister, and when that didn’t work, I filed an Official Information Act request. The reply came from Simon Lawrence at Fisheries New Zealand, but it wasn’t what I hoped for. They’re only planning to review four out of the 16 unmanaged populations this year – Flatfish, Rig, Blue cod, and Red cod. That leaves Pipi, Horse mussel, Paddle crab, Anchovy, Sprat, Pilchard, Jack mackerel, Pōrae, Leatherjacket, Trumpeter, Longfin eel and Spiny dogfish unmanaged. Four of these fish are at the bottom of the food web and are critical for the Gulf ecosystem function. Horse mussels are endemic (found only in New Zealand) and aggregations dense enough to be called beds are now extinct in the Gulf, Longfin eel are also endemic and going extinct.

So here we are, with a fisheries plan that talks a big game about moving towards an ‘ecosystem-based fisheries management‘ approach, but we’re not even effectively managing individual fish populations.

Anchovy Engraulis australis kokowhaawhaa
 Jack mackerel Trachurus declivis Trachurus novaezelandia Trachurus murphyi Haature
New Zealand pilchard Sardinops sagax Mohimohi
New Zealand sprat Sprattus muelleri Kupae
Smooth leatherjacket velvet leatherjacket Meuschenia scaber Kokiri
Trumpeter Latris lineata Kohikohi
Porae Nemadactylus douglasii Morwong
Spiny dogfish Squalus acanthias snow fillets Makohuarau Pioke
Longfin eel Anguilla dieffenbachii Tuna
paddle crab  Ovalipes catharus Pāpaka
horse mussel Atrina zelandica Hururoa
pipi  Paphies australis

New Zealand’s dairy industry

New Zealand dairy industry

Environmental reports and main stream media are often critical of different aspects of the New Zealand dairy industry. Here I summarise them together in one graphic. View at higher resolution by clicking on the image below.

Graphic summary of the New Zealand’s dairy industries impacts.

References – resources for further reading on the impacts of New Zealand’s dairy industry.

Map of dog prohibited area at Tahuna Torea Nature Reserve

Map of dog prohibited area at Tahuna Torea Nature Reserve

Like many locals I regularly ask people to not walk their dog at Tahuna Torea Nature Reserve. Sometimes dog walkers push back and say they are allowed to walk their dogs on the beach or around the top of the track. To make it clear here is the wording from the Auckland Council website:

“Dogs are prohibited at all times in Tahuna Torea Nature Reserve. This covers all park areas and associated beach and foreshore areas from the public walkway between 24 and 26 Vista Cresent to its boundary on West Tamaki and Tahaki Roads.”

Here is a map to visually explain the area.

To map the “beach and foreshore areas”, I projected the boundaries perpendicular to the starting points on land, down to the low tide line. Mean Low Water Springs (MLWS) has been visually estimated.

Update March 2024

Roberta Reserve also excludes dogs on the foreshore and playground. There is an exemption for the area in the water of the stream mouth seaward side of the bridge on Roberta Reserve.

Submissions on the protections proposed by Revitalising the Gulf

I spent a few days going through the 7,550 submissions on protections proposed by Revitalising the Gulf. I’m estimating 77%-90% of the submissions were positive about the protection proposals. However huge numbers concerned about the continuation of bottom impact fishing outside the protected areas and cultural take inside them. So there is a general need for more protection. This level of public support for marine protection can be expected and can be seen in Polling from the Hauraki Gulf Form, Submissions on the recent Waiheke Marine Reserve Proposal and the Live Ocean Barometer 2023.

Most of the names were redacted from the submissions but the organisation names were left public. Here are the names of the organisations that made significant submissions.

2xs Charters / Balmain Boating Services
Alan Seasprite Charters
CRA 2 Rock Lobster Management Co
Dr Hook Charters
Fisheries Inshore NZ
Kina Industry Council
Mercury Bay Game Fishing Club
NZ Rock Lobster Industry Council
New Zealand Charter Boat Association
New Zealand Sport Fishing Council
Paua Industry Council
Princess Carol Charters
Provider Adventures Ltd
Sea Urchin NZ Ltd
Seahawk Fishing Charters
Slipper Island Residents Association
Snap Attack
Specialty & Emerging Fisheries Group
Tairua Adventures Ltd / Artisan Fishing Co
Te Ohu Kaimoana
Te Ra Charters
The New Zealand Angling & Casting Association
Whitianga / Coromandel Peninsula Commercial Fisherman’s Association
Aldermen Islands Marine Reserve Group
Friends of the Hauraki Gulf
Mama Fish
Sanford Limited
Forest & Bird
Revive Our Gulf
Auckland City Centre Residents Group
Auckland Conservation Board
Auckland Council
Auckland Sea Kayaks
Auckland Sea Shuttles
Coromandel Marine Farmers Association
Devonport Yacht Club
Environmental Defence Society
Foundation North
Friends of Taputeranga Marine Reserve Trust
Goat Island Dive and Snorkel
Good Fishing
Hahei Residents and Ratepayers Association
Leigh Penguin Project
Live Ocean Foundation
Meadowbank School Marine team
Motuora Restoration Society
Mountains to Sea Conservation Trust
New Zealand Conservation Authority
New Zealand Geographic
New Zealand Marine Sciences Society
Ngāti Hei
Ngāti Manuhiri Settlement Trust
Ocean Voyages Inc
Pakiri Community Landcare Group
Pest Free Kaipātiki
Ports of Auckland Limited
Shakespear Open Sanctuary Society Inc
Sir Peter Blake MERC
Supporters of Tiritiri Matangi
Te Whanau o Pākiri
The Friends of Te Whanganui‐A‐Hei Marine Reserve Trust
The Glass Bottom Boat Whitianga
The Hauraki Gulf Conservation Trust
The Hauturu Supporters Trust
Tāmaki Estuary Protection Society
Tāwharanui Open Sanctuary Society Inc
Waiheke Marine Project
Waikato Regional Council
Wakatere Boating Club
Yachting New Zealand
Most of these submitters were upset about continued bottom impact fishing in the Gulf. Most of the Charter fishers all sent in the same submission. These submitters indicated support for marine protection but did not express that much support for the proposed measures: Most of these submitters wanted more protection than what was proposed and also wanted bottom impact fishing banned.

I have not published the names of many organisations who used the LegaSea form as those submissions contained dramatically less information than those from the above organisations. They were mostly small owner operator companies who are also keen fishers. The big Purse Sein operator Pelco NZ Ltd and Te Ahu wai o Tangaroa sustainable ecological aquaculture did make significant submissions but they did not speak to the protection proposal.

In response to the submissions the Department of Conservation has reduced the amount of protection. Submissions are now open on the Hauraki Gulf / Tīkapa Moana Marine Protection Bill.

P.S. These bottom impact fishing effort maps were made public by Fisheries Inshore NZ and are useful in considering the proposed ‘trawl corridoors’.

Digging up our streams

I took this photo last week of earthworks in a stream in 70 Estuary Drive, Mangawhai Heads. I contacted Kaipara District Council to see if it was compliant (Job number SR2304941). They phoned me to say the landowner had a consent for earthworks (it had been extended). Apparently the landowner had dug out the area as recent rain had turned it into a swamp which was a danger to children. I told the officer that another set of eyes may have called it a wetland, however as I did not have a pre-earthworks photo as evidence I could not take my complaint further.

My experience in designing ‘trawl corridors’

Unlike the Sea Change 2017 marine spatial plan that sought to phase out bottom impact fishing from the Hauraki Gulf Marine Park the governments response (Revitalising the Gulf 2021) was to create ‘trawl corridors’. Bottom trawlers do not have a public license to keep smashing the seafloor, a 2021 Horizon Research poll had 84% support for a banning the practice. I love the seafloor and volunteer for an organisation that restores damage done to it by bottom impact fishing. I’m completely opposed to trawling as a fishing method but I put my hand up to help limit its impact in the Gulf using a science based process by joining the Hauraki Gulf – Benthic Spatial Planning Advisory Group (HG-BSPAG).

This was my first experience in a collaborative decision making process run by the Government with industry representatives. I represented an environmental Non-Government Organisation (eNGO), there were three eNGO participants, everyone else was either from NIWA, central & local govt or the fishing industry. The process was chaired and controlled by Fisheries NZ. The other two eNGO participants were awesome and I learnt a lot from them.

I particularly liked the data first approach to marine spatial planning, Zonation is a great tool and I liked the way it starts by removing the human impacts then making an economic case for re-introducing them. Unfortunately some data that would have been useful was not quite complete.

Fisheries NZ controlled the outputs by defining what is in scope. Here is a list of requests that were disregarded:

  1. Ground truthing the modelling work (out of scope).
  2. Modelling the distribution of Unwanted Organisms (UOs) . We know from NIWA surveys that trawl nets catch UOs in the HGMP, transporting UOs is an offence under Section 52 of the Biosecurity Act 1993. By excluding UO’s from the study FNZ failed to protect native benthic habitats from UO’s which can be spread by bottom impact fishing (see appendix for more details).
  3. Infauna (animals that live in the sediments) that are sensitive to bottom impact fishing were excluded from the modelling due to technicalities.
  4. Mobile species that contribute biogenic habitat like tipa / scallops (see appendix) and burrowing animals like ghost shrimp and crabs were excluded because they were mobile which did not suit their definition of biogenic habitat. This is ridiculous as the smallest grid size is 250m and previously mentioned adult animals are unlikely to move more than 10m.
  5. Important habitats for fish (like spawning and nursery areas) were not considered (out of scope).
  6. The indirect effects of bottom impact fishing. Sediment plumes from bottom impact fishing choke and kill filter feeding animals and smother photosynthesising plants. These effects were not included but have been discussed at the end of the report.
  7. Climate change impacts (e.g. CO2 released from resuspending sediments and heart urchins moving deeper as water warms) also not included but have been discussed at the end of the report.
  8. Modelling the economic benefits of excluding bottom impact fishing to other fisheries that don’t impact the seafloor, this could have dramatically altered the findings (out of scope).
  9. Monitoring changes in the money made in an area over time during the transition from one fishing method to another, I think it’s critical this is done with any changes to bottom impact fishing.
  10. Using the regulations, not existing fishing effort, as the starting point for limiting Danish seining (see appendix on Danish seining regulations). Despite multiple requests FNZ would not even put the existing regulations on the maps.
  11. Protecting the deeper areas of the HGMP (see appendix).

We did not discuss substrate. Is it better to trawl on sand which emits a smaller plume but may transition to mud with intensified disturbance, or mud which has a larger sediment plume? We know repeated bottom impact fishing alters the chemistry of the seafloor.

The narrow scope of the project was frustrating because there is an aspiration for Ecosystem Based Management of the Hauraki Gulf Marine Park. Once all the environmental effects of bottom trawling and Danish seining are considered, the fishing methods should be banned everywhere.

I have some sympathy for fisheries managers, they have specific deliverables and get pushed around by industry. I did think their approach was often callous, in the face of uncertainty they often chose the status quo rather than taking a more precautionary approach. One member of the Hauraki Gulf Fisheries Management Plan Working Group HG-FMPWG that will finish the corridor design work has publicly criticised the process.

There were no opportunities for feedback on the corridors the scenarios produced. Final trawl corridor design will be Fisheries NZ’s responsibility and will get input from the HG-FMPWG. Other than the above I have no criticisms of the process, it just needs bigger budgets and managers who care more about te taio. I learnt a lot and am happy to volunteer my time again to use scientific modelling in a spatial planning process to protect the environment.

One difficulty I had was proposing trawl corridors. I decided not to volunteer a low impact scenario because the process had already generated a near zero impact scenario which I thought was reasonable (Similar to Figure 14C in the published report – 90% of recovery potential habitat and current trawl footprint & current/proposed protected areas and 100% of current distribution of biogenic habitat (minimising impacts on trawl fishery.) This meant I was left very unhappy with the scale of the proposed scenarios. It was obvious that the scenarios would need work before Fisheries NZ could designate corridors, however I may end up regretting that decision.

I hope Fisheries NZ will monitor recovery (which may take centuries) the data gained could help ground truth this model and develop more robust models in future.

You can read the published report on the design process here: Exploring the use of spatial decision support tools to identify trawl corridors in the Hauraki Gulf Marine Park

Advice for the Hauraki Gulf Fisheries Management Plan Working Group

The outputs of the process will be used by the Hauraki Gulf Fisheries Management Plan Working Group to design bottom trawling corridors in the marine park. Here are some key points they should be aware of:

  • Because the process is not ground truthed and does not account for secondary impacts, important habitats for fish or climate change impacts a precautionary approach should be taken. (I suggested massive buffers but they were deemed out of scope).
  • Danish seining impacts have not been included in the model. This skews the impacts, recovery in areas where this fishing method is practiced has been understated.
  • The corridors should be much deeper (further from the coast) to avoid the illegal transport of Unwanted Organisms.
  • Consider the existing Danish regulations as the starting point, not the area where the fishing method is currently practiced.
  • Protect the deeper areas of the Gulf because they are included in the Hauraki Gulf Marine Park (see appendix).
  • Include monitoring (fisheries method transition) in any recommendations.
  • Take special note of the sediment resuspension impacts detailed on page 68 of the report which were excluded from the study.


Avoiding tipa / scallop beds

Running heavy trawl gear over tipa / scallop beds is incredibly damaging and foolish behaviour. It not only damages the tipa including juveniles, but also the settlement substrates the tipa use as part of their lifecycle. The Review of Sustainability Measures for New Zealand scallops (SCA 1 & SCA CS) for 2022/23. 3.1.18 states that:

“Within the Hauraki Gulf Marine Park, overlap between trawl activity and scallop beds will be considered as part of the proposal to establish defined ‘trawl corridors’ that will limit the areas where bottom trawling can continue to operate. With the introduction of electronic reporting and Global Position Reporting (GPR) on commercial fishing vessels, Fisheries New Zealand has the ability, through fine scale data, to monitor any notable overlap between fisheries and methods.”

It was frustrating that even though tipa are the most surveyed biogenic habitat in the Gulf the fisheries scientists decided that instead of identifying them they would just model their associated habitats. In the paper they literally say they ‘hope’ that this would mean the beds would be avoided rather than just mapping them out. Only the small beds that remained open at the time of the study (the fishery has since collapsed with bottom impact fishing implicated as a key stressor) were removed from the study area.

The rationale for the exclusion of tipa was that they are very mobile. This is ridiculous given the grid size of the study is 250m. Adult tipa and burrowing animals are unlikely to move more than 10m in their lifetime. For adult tipa mobility see Morrison, M. A. (1999). Population dynamics of the scallop Pecten novaezelandiae in the Hauraki Gulf (Doctoral dissertation, ResearchSpace@ Auckland).

Danish seining regulations

The restrictions prescribed in fisheries regulations for Danish seining define a different area than what is currently applied by Fisheries NZ. The State of our Gulf 2020 quotes Fisheries  NZ as ‘committed to reviewing this discrepancy as part of management actions put forward in a fisheries plan for the Hauraki Gulf’. The discrepancy is not recorded in the final report.

Protecting the deeper areas of the HGMP

The deeper areas of the HGMP were excluded from the final scenarios. I asked that they be protected because:

  1. The edges of continental shelves are biodiversity hots spots. Predicted diversity along the depth incline is one of the reasons for excluding the area from the model.
  2. This process was designed to protect biodiversity.
  3. This is the only deep water area in a marine park in New Zealand.

Unwanted organisms discussion document

Here is the discussion document on an unwanted organism (Mediteranean fanworm) I prepared for the working group, similar logic could have been applied to other species including the two recently introduced Caulerpa species.


The report details protection measures proposed by Sea Change 2017 but omits the most important benthic protection measure, “the phase out of all bottom trawling, Danish seining and scallop dredging from the Hauraki Gulf, with all such methods excluded by 2025” It’s a strange omission that reads like an attempt to exclude the measure from the history books.

Northern New Zealand dotterel productivity rates

Northern New Zealand dotterel are classified as a Conservation Dependent species, this means that without human help they will go extinct (usually because of predation from introduced predators like rats & cats). So how do you know if your local dotterel are going extinct or not?

Well first you need to work out their productivity rate. Productivity is measured by the average number of chicks fledged per breeding pair (per season). Chicks divided by adults. So if you had two pairs and they fledged one chick you can say the site averaged half a chick (0.5) per pair.

Management is considered effective if productivity values are greater than 0.5 for three consecutive years or longer (Dowding & Davis, 2007).

I help manage dotterel at three sites, I can not claim effective management and any of them. This means that over time these sites are a population sink. It’s important to track and share this metric to help conserve the species.