Māui dolphins are endemic to Aotearoa New Zealand and are found on the west coast of the North Island.
The New Zealand Government recently developed a ‘spatially explicit fisheries risk assessment’ (SEFRA) that maps the distribution of Māui dolphins and compares it to the areas where fishing that can pose a risk to Māui dolphins occurs (e.g. set netting).[1] The SEFRA model is based on sightings recorded through standard scientific approaches.[2] This allows the overlap between dolphins and fishing to inform our understanding of risk of interaction (and consequent injury).
As a ‘surfer scientist’, sightings of Māui dolphins can be reported by phone, app, or web form. Aside from surfers, sightings are reported by many different people, including boat users and recreational fishers.
A key use of this data is to corroborate the spatial predictions that are made from the habitat model. The programme also raises public awareness and engagement.
However, only a select number of sightings are used in the model to estimate the relative density of Māui dolphins in harbours. The reason why many are not used is because to estimate density there needs to be an understanding of the ‘effort’ that has gone into the sightings.[1] In practice this means that only sightings from recreational fishers are used in estimates, as in this case effort can be estimated from aerial surveys of numbers of recreational fishing vessels in the areas.
Currently a large number of validated sightings, including rare ones, are discarded because of the lack of effort information. A recent study looked at whether surfer ‘effort’ could be estimated so that data collected by surfers could also feed into density estimates.[3] Surfer effort would be based on the density of surfers, how likely they are to report a sighting, and the number of days surfers were available to make a sighting. The research showed that in-person survey of surfers allowed for appropriate data to be gathered to estimate effort and include surfer-collected data in SEFRA. These findings indicate that there are ways to enable the use of more surfer sightings to increase applicability of this tool to protect Māui dolphins and support sightings recorded through standard scientific approaches.
While public sightings are not a substitute for validating the SEFRA habitat model with data collected by scientists in a controlled fashion, surfer scientist data has the potential to grow the knowledge base around Māui dolphins and also expand to support wider data collection, such as collecting eDNA (see section: Environmental DNA (eDNA) can grow ecosystem knowledge).
Poster advertising Māui dolphin project (above) and screenshot of the app where people can report a sighting of a Māui dolphin (below).
References and footnotes
[1] Roberts, J. O. et al. (2019) Spatial risk assessment of threats to Hector’s and Māui dolphins (Cephalorhynchus hectori), New Zealand Aquatic Environment and Biodiversity Report No. 214.
[2] Taylor, B. et al. (2018) Appendix 1 – Hector’s and Māui Dolphin Threat Management Plan Review, Risk Assessment Workshop, 9-13 July 2018. Panel Comments and Recommendations, pp. 15.
Discusses limitations of the SEFRA model, including the need for further validation of inputs.
[3] Beeman, I. L. et al. (2019) The Brink of extinction: Saving the Maui dolphin using surfer science.