Abstract:
Bioaccumulation and toxicity of heavy metal pollutants has the potential to contaminate
marine systems when present in high concentrations. For centuries, seabirds have been
used by Indigenous communities to determine the health of marine systems. More recently,
Western science has also recognized seabirds as useful indicators to monitor elevated risk
of marine pollutants. This project aims to explore the role of seabirds as indicators of ocean
state using a ‘tohu’ framework that reflects a kaitiakitanga-based natural resource
management. This advocates for a natural resource co-governance model by drawing upon
the knowledges, values and ethics of western and Māori world views. Following a kaupapa
Māori based methodology, three customary harvest mutton-bird species (Ōi (Pterodroma
gouldi/grey faced petrel); Tītī (Puffinus griseus/sooty shearwater; and Toanui (Ardenna
carneipes/flesh-footed shearwater) were investigated using both qualitative and quantitative
methods. Semi-structured interviews identified three key themes in resource management of
these birds by Māori: harvesting practices, kaitiakitanga, and whanaungatanga. Harvest
practices had a bottom-up governance approach creating diverse harvesting techniques that
adapt to local environments. Kaitiakitanga identified mana whenua rights in and power-
sharing in natural resource management as a requirement for success. Whanaungatanga
also identified relationships and collaboration as a vital component. Inductively coupled
plasma mass spectrometry (ICP-MS) and laser ablation ICP-MS (LA-ICP-MS) were used to
analyse a 22-elemental suite of feather ōi, tītī, and toanui feathers. These were compared
against species, sex, age, blood heterophil-lymphocyte (H:L) ratios, feather deposition
patterns, and life stage. Compared with tītī and toanui, ōi had the highest levels of Hg whilst
toanui recorded the lowest concentrations of Mn and Cu of the three species. As these
species forage and migrate to different marine areas, this may reflect marine elemental
compositions. In adult ōi, Hg and Se were positively correlated with age. Whereas ōi chicks
had the highest Hg feather concentrations compared to fledged chicks and adults. This may
have implications for the consumption safety of ōi chicks. Variations in feather metal
deposition in mid-to-upper sections of the feather rachis. Thus, clipping samples from these
sections is sufficient for sampling which is far less invasive than removing an entire feather.
No differences were found between ōi feather elemental composition and H:L ratios and sex.
These novel findings inform both conservation efforts and customary harvest practices.
Genuine cross-cultural collaboration is imperative to successfully address the health of these
birds, marine health, and the communities consuming these birds.