Large marine predator aerial survey data for Hauraki Gulf, New Zealand

Large marine predators, such as cetaceans and sharks, play a crucial role in maintaining biodiversity patterns and ecosystem health. Despite the recognised importance of these animals and their over-representation as threatened species, distribution data at appropriate temporal and spatial scales is often lacking or insufficient for effective conservation. 
Here, we present sightings of large marine megafauna recorded from a replicate systematic aerial survey undertaken in the Hauraki Gulf, Aotearoa New Zealand during a full year. Using flexible machine learning models (Boosted Regression Tree models), we use these sightings data to investigate relationships between large marine predator occurrence (Bryde’s whales, common and bottlenose dolphins, bronze whalers, pelagic and immature hammerhead sharks) and spatially explicit environmental and biotic variables to predict species richness of large marine predators and investigate their fine-scale spatiotemporal distribution patterns. All m..., Study site
The Hauraki Gulf (36⁰ 10’–37⁰ 10’ S; 174⁰ 40–175⁰ 30’E) is a large (~4,000 km2), semi-enclosed embayment situated on the northeast coast of the North Island – Te Ika a Māui, New Zealand.
Replicate systematic aerial survey design and protocol
Twenty-two double observer line-transect aerial surveys were conducted typically twice a month from November 2013 to October 2014, following MacKenzie and Clement (2014). Surveys followed a systematic grid of eight parallel transects evenly spaced apart every 10 km, orientated offshore at 62° from the north. Under this design, it was possible to sample across a wide range of environmental conditions. The survey followed a simple, unstratified design due to a wide range of species with different or unknown distributions (Dawson et al. 2008). To ensure equal coverage probability (i.e., a random sample of the total habitat area in the survey area; Buckland et al. 2004) the start point of each survey was randomly chosen using the striplet met..., All files provided can be opened using the open source software R and R-studio.