Dataset for "Swimming nets have positive effects on populations of the endangered White’s seahorse Hippocampus whitei"

Abstract

This is the dataset for all analyses performed in the manuscript titled "Swimming nets have positive effects on populations of the endangered White’s seahorse Hippocampus whitei" published in the journal "Aquatic Conservation: Marine and Freshwater Ecosystems". The main aim of this study was to assess whether swimming nets result increased seahorse numbers at sites around Sydney Harbour, as these structures are often used as habitat by the Species H. whitei. It contains observational H. whitei density (seahorses per 5 minute timed survey) to test the hypotheses that A. seahorse density will be greater on pre-existing swimming nets than on surrounding seagrass and B. that there will be a difference in seahorse density on seagrass at sites where a swimming net is either present or absent. Closed-population presence-absence data (to be analysed in Program MARK) for tagged seahorse populations at sites where a net is present (Manly Bay and Clifton Gardens) or absent (Fairlight and Delwood Beach). Seahorse density data for a repeated measures analysis is contained for seahorse populations A. on seagrass at sites where experimental net panels were installed with comparisons to control sites and B. on installed net panels themselves with comparisons to surrounding seagrass to assess the effects of installed net panels on seahorse populations. The mean seahorse density at each site for each survey occasion is provided to create regressions to assess long-term trends in seahorse density. Finally, open-population seahorse presence-absence data for tagged seahorses at all sites where experimental nets were installed is contained, as well as population data for control sites. Kaplan-Meier datasets are also contained for analyses that assess whether site-persistence differs on seagrass at sites where nets are present or absent, as well as assessing whether site-persistence differs across habitat types (swimming nets or seagrass). This data is sorted into the subheadings A. Assessing seahorse populations at sites with pre-existing swimming nets, B. Assessing the effects of installed experimental swimming net panels on seahorse populations and C. Seahorse population analysis, as per the results subheadings of the published manuscript.