Improved bathymetry leads to 4000 new seamount predictions in the global ocean

Seamounts are important marine habitats that are hotpots of species diversity. Relatively shallow peaks, increasedproductivity and offshore locations make seamounts vulnerable to human impact and difficult to protect. Present estimates ofseamount numbers vary from barely 10000 to more than 60000), because locating and identifying them remotely can bedifficult. Seamount locations can be estimated by extracting conical shaped features from bathymetry grids. These predictedseamounts are a useful reference for marine researchers and can help direct exploratory surveys. However, these predictionsare dependent on the quality of the surveys underpinning the bathymetry. Historically, quality has been patchy, but isimproving as mapping efforts step up towards the target of complete seabed coverage by 2030.This study presents an update of seamount predictions based on the most recent SRTM30 global bathymetry. This updatewas prompted by a seamount survey in the British Indian Ocean Territory, where locations of two putative seamounts, basedon several previous global seamount predictions, were visited, but no such features were detected during echosoundersurveys. An examination of Admiralty charts for the area showed that the summits of these putative features had soundingsreporting no bottom detected at this depth where this depth was similar to the seabed reported from the bathymetrygrids: we suspect that these features likely resulted from an initial misreading of the charts. We show that perhaps 15phantom seamount features, derived from a misinterpretation of no-bottom sounding data, persist in current globalbathymetry grids and updated seamount predictions. Overall, we predict 37,889 seamounts, an increase of 4,437 from theprevious prediction derived from an older global bathymetry grid. This increase is due to greater detail in newer bathymetrygrids as acoustic mapping of the seabed expands