In December 2020 I jumped at the chance to help the Department of Conservation and Auckland Zoo with New Zealand’s most endangered bird. I provided 3D printed fairy tern models (that were designed for use as decoys) to Zoo staff who hand reared a chick through to fledging. A soft yellow tape was wrapped around the models beaks to make sure the valuable chick did not injure itself. The models stayed with the chick to its aviary bach until it learnt to fly and feed for itself.
In November I sent this letter to Auckland Councils Environment and Climate Change Committee along with this report. This morning I was invited to present to the Mayor of Auckland and the committee (presentation here) the report and letter were well received and I answered many questions from engaged Councillors. A response is being drafted.
I was pleased to read about Dr Mark Morrison’s 2020 discovery of tubeworms colonies in the Hauraki Gulf. The Marine Park has been heavily impacted by bottom impact fishing and epi-benthic biogenic habitat is now hard to find. I wanted to see what the tubeworm colonies looked like and how the wildlife differed from degraded seafloor.
I was therefore very excited to be invited on an expedition to inspect some tubeworm mounds discovered by Shane Kelly and Carina Sim-Smith near Moturua Island. They were relatively deep at about 25 meters whereas Mark Morrison’s ones were in the 12-22 meter range. The conditions were perfect with no wind and clear skies. We descended very quickly into the dark as we knew at that depth we would only have about half an hour to explore the area.
Scarlet tubeworm colony (Galeolaria hystrix)
I was stunned at the size of the mounds, they rose up to nearly a meter from the seafloor (much taller than any shellfish bed) and reminded me of coral reefs. Tubeworms grow in a similar way to coral, layering their calcareous skeleton homes upon each other as they filter feed and grow upwards. And just like some corals when I got about half a meter away from the tubeworms they retracted their red tentacles in a Mexican wave across the mound, it was really beautiful and I should have made a video of it.
The diversity was incredible, I was amazed at the amount of filter feeding colonial epifauna growing on the mounds. I wondered if the sponges, ascidians, anemones (which are also filter feeders) were competing with the tubeworms or if the relationships were commensal.
Conger eel
I don’t know the surrounding area but I was surprised to see so many fish including a young sandagers wrasse. This conger eel living in the mounds was a real highlight and I wish I had gotten a better photo. Goatfish were the most abundant fish species.
While the scientists collected a few specimens for identification I took two minutes to record a video which I later converted into an orthomoasic map using this technique (which I am still polishing). The map revealed an interesting pattern similar to that made by restored mussels as they clump together over time. It would be good to validate it by mapping more filter feeding structures.
The fragile mounds are easily damaged by dredges and trawlers, it’s likely that fear of catching gear on anchors from the adjacent mussel farm has protected the beds. The experience has me wondering what a huge protected tubeworm colony might look like, and how can we make more of these incredible structures.
I have spent a fair bit of time thinking about how citizen scientists can measure the health of their local streams using Macroinvertebrate Community Index (WIMP & SHMAK) and the index of biotic integrity (IBI) for New Zealand fish. The great thing about using stream life to measure stream health is that the animals act as 24/7 sensors that measure any of the countless pollutants that harm life. The problem with it is that finding and more importantly identifying species involves disrupting them.
eDNA (environmental DNA) sampling solves this by measuring the presence of stream life base on the tiny fragments all life constantly erode into water. Wilderlab have set up a testing system with relatively cheap kits available for citizen scientists. I found it easy to use on my local stream (which is very degraded). I am really excited about this technology, especially as the price comes down and results are benchmarked against existing stream health Indices.
This artificial shag roost in Hobson Bay was constructed by Auckland Council to mitigate the effects of a boardwalk being constructed next to an existing shag roost. Nesting materials and a plywood decoy has been added but the birds are yet to show interest in it.
As communities get increasingly worried about the declining quality of their waterways there is more interest stream health assessments. I am a huge fan of the Waicare Invertebrate Monitoring Protocol (WIMP) which is simple enough that school students can use it. However the Waicare programme has been largely defunded by Auckland Council and there is no way for the public to share WIMP data. NIWA and Federated Farmers of New Zealand have put together https://nzwatercitizens.co.nz/ based on the New Zealand Stream Health Monitoring and Assessment Kit (SHMAK). It is great but incredibly hard to use, the manual is horrific. I believe this is being addressed but will take years. To help, the science learning hub has made this great guide for teachers and students. NIWA have put together some videos. They are not published together anywhere online so I have posted the list below:
I really like this list of alternative words for environmental terms, offered by George Monbiot & Ralph Steadman. I have rebuilt it in HTML with some additions and deletions, I plan to evolve it over time.
Existing terms
What’s wrong with it
Alternative terms
Environment
Cold, technical Seen as seperate
The natural world
Global warming
Warm sounds pleasant
Global overheating
Biodiversity
Inaccessible
Wildlife
Ecosystem services
Anthropocentric and reductive
Life support systems
Nature reserve
‘reserve’ suggests coldness
Wildlife refuge
Habitat destruction Deforestation Biodiversity loss
Sounds like they are happening to themselves
Ecocide
Conservation
Preserving what little is left rather than rebuilding living systems (New Zealand needs a department of Restoration)
Restoration
Clean rivers / seas
Sounds too hygienic, is blind to waters as habitats
Thriving rivers / seas
Fossil fuels
Suggests redundancy
Dirty fuels
Sustainable development
Green growth is an oxymoron
Regenerative development
Photopollution
Too technical, doesn’t indicate what is being impacted
Ecological light pollution
Stormwater
Suggests that the water is unwanted, unnecessary or unsavoury
Rainwater
MARINE
Fish stocks
Suggests fish are here to serve us
Wild fish populations
Biofoul, foul, foul ground
Suggests there is something ugly about biogenic habitats
Sea life, seafloor life, benthic epifauna
Fishing
Casual everyday activity
Killing native wildlife
Bait fish
Implies the fish exist to be bait
Small schooling fish / forage fish / small pelagic fish / shoaling fish
Marine restoration is a lazy business. All you have to do is stop fishing an area and marine ecosystems heal themselves. However this is not the case with green-lipped mussels in New Zealand.
100’s of square kilometres of sub-tidal mussel beds were fished to extinction in each harbour around New Zealand.
The industry collapsed and more than half a century later they have not returned. In the Hauraki Gulf there are a few places you can still find Green-lipped mussels. You would think that these places would be deep under the ocean (Green-lipped mussels have been found at 50m deep), but they are not.
Most are in the intertidal zone on rocky shores. Here there is usually a gradient with mussels thin higher up and getting thicker towards the low tide mark where the abruptly stop. I have asked several local experts and no one has a solid answer why they stop so abruptly.
As we spend 100’s of thousands of dollars restoring sub-tidal beds maybe the key to unlocking a lazier (and cheaper) solution is staring us in the face. Here are some thoughts on why the line exists:
Avian predation. Every exposed mussel bed has at least one pair of Variable oystercatcher eating the smaller mussels every low tide. So living in the subtidal zone would be of some advantage but we are more likely to see juveniles higher up. This suggests there is even more predation from below.
Starfish predation. Eleven-armed star fish were a big problem in the first beds put down by Revive our Gulf. However starfish do okay in the intertidal zone and are not particularly abundant in intertidal beds. We don’t see lots of them waiting below the low tide mark next to intertidal mussel reefs.
Fish predation. This seems like the most obvious cause but surely it can’t be Snapper as they have been fished down to 20% of their natural biomass. Rays are a possibility but I thought I would see more of them in the shallows if this was the case. This southern study looked at predation and found it to be largely subtidal and nocturnal, by fish and large crabs.
Octopus predation. They are nearly invisible and love eating mussels so at first this is a good fit. But octopus leave the shells, I will look for evidence on the next intertidal bed I explore. None of the predation theories show why the line is so strong.
Food. Mussels eat phytoplankton and algae. I am sure there will be more of this close to the surface. I am pretty sure this is why mussel farmers grow their mussels high in the water column. Wild mussels might also benefit from wave action on the rocks as it would increase the oxygen in the water. However I would have thought that these benefits would be offset by the fact they can’t feed while they are exposed to the air.
Sediment. If there is some other benefit to being exposed to the air maybe it’s that the water in the Gulf just has too much stuff in it. Mussels have to work hard sorting out the food from the dirt, maybe mussels are not good at taking a break and being forced to is good for them. Comparing the condition of intertidal and sub-tidal mussels would help dismiss this idea.
Or maybe like a lot of things in biology it’s a mixture of the above factors. As we are slowly losing our intertidal mussel beds it might be wise to set up a long-term monitoring project that might solve this mystery and inspire lazier restoration methods.
I have 1,612 verified observations on iNaturalist between Auckland and Whangarei documenting 552 species (mostly invertebrates) covering forest, freshwater, intertidal and marine habitats. I don’t take many photographs of plants. Of these observation 96 or 17% of species were introduced. Here is a break down showing areas where I have found more or less introduced species:
Hauturu
Aotea
Tawharanui
East Auckland
Waitakeres
Hunua Ranges
Rangitoto / Motutapu / Motuihe
Motukorea
Mungatapere
Observations
206
149
141
197
77
94
71
33
159
Species
86
84
86
120
57
64
52
25
83
Introduced
6
12
8
35
1
4
11
4
9
Percent introduced
7
14
9
29
2
6
21
16
11
I expected the restored and protected islands in the Hauraki Gulf to have a smaller percent of introduced species. I think the high number of introduced species (compared to the Waitakeres and the Hunua Ranges) reflects the islands farmed history with islands like Motukorea and Motutapu still dominated by kikuyu. The larger and older the forest the more indigenous biodiversity.
I teamed up with computer and environmental scientist Jordi Tablada to build a website for identifying New Zealand animal sign. I met Jordi through the New Zealand Dotterel Forum as he looks after dotterel at Piha. We had overlapping skills and were looking for a project to collaborate on. He came to me with the idea inspired by some materials produced by another dotterel minder Emily Roberts.
Now when I spot tracks in the sand and wonder what made them I load up the website and check them against the examples. It’s working really well and I hope to expand it to include other animal sign and more species. Others are using it too, mostly due to some great press. It was inspiring to see another citizen science identification guide go live this morning which will also help on beaches. This one is for shells.
These guides join others produced by organisations like nzbirdsonline.org.nz and help users of tools like eBird and iNaturalist.nz map the diversity and abundance of New Zealand flora and fauna.
