Global port environmental data used for environmental distance calculations

This dataset includes 6,727 global ports, providing geographic coordinates and four environmental variables: mean temperature of the warmest and coldest months, mean monthly temperature, and mean monthly salinity. All measurements were taken from surface water. Primary data sources include Wang et al. (2015), World Ocean Atlas 2018 (Locarnini et al. 2018; Zweng et al. 2018), and Wanders et al. (2019). Data for estuarine and riverine ports were adjusted where better information was available, with a focus on Canadian ports and last ports of call for ships arriving in Canada.

Methods
A global list of 6,727 ports was compiled using data from Keller et al. (2011), with additions from the Canadian Ballast Water Information System based on transit histories (e.g. last port of call) of ships arriving at Canadian ports. In version 2 (2025), duplicate ports were combined, misidentified non-port locations were excluded, and several coastal communities in the Canadian Arctic that receive vessel traffic were included. The port environmental data includes four variables: mean temperature of the warmest and coldest months, mean monthly temperature, and mean monthly salinity. Mean monthly data were incorporated in version 2, primarily sourced from Wang et al. (2015), World Ocean Atlas 2018, and Wanders et al. (2019). All measurements were taken from surface water. Annual temperature and salinity estimates were calculated based on monthly means. For ports lacking monthly salinity data (e.g. estuarine ports), annual estimates from Keller et al. (2011) were used, though these do not account for seasonal variations. These estimates were adjusted when better data were available. Data were verified and updated through literature reviews and communications with local experts. 'n/a' indicates an empty cell (no data available).

Data sources:

Keller, R.P., Drake, J.M., Drew, M.B., and Lodge, D.M. 2011. Linking environmental conditions and ship movements to estimate invasive species transport across the global shipping network. Diversity Distrib. 17: 93–102. https://doi.org/10.1111/j.1472-4642.2010.00696.x

Locarnini, R.A., Mishonov, A.V., Baranova, O.K., Boyer, T.P., Zweng, M.M., Garcia, H.E., Reagan, J.R., Seidov, D., Weathers, K., Paver, C.R., and Smolyar, I. 2018. World Ocean Atlas 2018, Volume 1: Temperature. NOAA Atlas NESDIS 81, 52 pp.

Wanders, N., van Vliet, M.T.H., Wada, Y., Bierkens, M.F.P., and van Beek, L.P.H. 2019. High-resolution global water temperature modelling. Water Resour. Res. 55: 2760–2778. https://doi.org/10.1029/2018WR023250

Wang, L., Riseng, C.M., Mason, L.A., Wehrly, K.E., Rutherford, E.S., McKenna, J.E., Castiglione, C., Johnson, L.B., Infante, D.M., Sowa, S., Robertson, M., Schaeffer, J., Khoury, M., Gaiot, J., Hollenhorst, T., Brooks, C.N., and Coscarelli, M. 2015. A spatial classification and database for management, research, and policy making: The Great Lakes aquatic habitat framework. J. Great Lakes Res. 41: 584–596. http://doi.org/10.1016/j.jglr.2015.03.017

Zweng, M.M., Reagan, J.R., Seidov, D., Boyer, T.P., Locarnini, R.A., Garcia, H.E., Mishonov, A.V., Baranova, O.K., Weathers, K., Paver, C.R., and Smolyar, I. 2018. World Ocean Atlas 2018, Volume 2: Salinity. NOAA Atlas NESDIS 82, 50 pp.