nwdaudt / munida_seabirds

Assemblages of seabirds off the Otago Peninsula, Aotearoa New Zealand

This is a work in progress, meaning this repository will be in constant change...

Can we define seabird assemblages based on water masses at coarse scale?

Here, we used a seabird observation dataset carried out during the Munida Time Series voyages to explore this question. The 'Munida Transect' runs bi-monthly a 60--65 km offshore transect departing from the Taiaroa Head (Otago Peninsula, Aotearoa New Zealand). The main goal of these Transects is to monitor ocean acidification, including several other biogeochemical markers. It has been going on since 1998, making the Munida Transect one of the longest time-series on ocean acidification globally. Despite its primary goal, the Munida Transect allows for collecting other samples---including visual surveys of marine megafauna, such as marine mammals and seabirds.

An interesting feature about this Transect is that it consistently crosses the Neritic, Subtropical and Subantarctic Waters, and very often, the Southland Front. Therefore, using seabird in situ observations while carrying out these voyages is an excellent scenario to test whether seabird occurrence responds to water masses even in 'small' scales (i.e. coarse scale, 1--100 km).

Seabird data spans from 2015 to 2023, and it consists of the maximum number of individuals counted (at once), within 5-km 'stretches' along the Munida Transect (up to 60 km offshore).