Marine Species Weightings

This page shows the weighting curves that can be selected from the database using the dropdown box. The database ships the NOAA 2016 and NOAA 2024 marine mammal hearing-group curves, the Southall et al. (2019) curves, the superseded NOAA 2013 curves (marked deprecated), and audiogram-based curves for a number of individual fish and marine mammal species. The None entry may also be selected when no weighting is desired.

The currently selected weighting curve is applied per frequency band, before summation, throughout the program to calculate weighted levels. The levels displayed in the main graphic window are weighted levels, except for the peak level types (Max sound pressure level, Peak sound pressure level and Peak to peak sound pressure level), which are always unweighted.

When exporting levels, overall weighted levels are exported. However, if spectra are included, the individual frequency components within each spectrum are exported as raw, unweighted levels.

Weighting in Time-Domain Solves

For time-domain solves, weighting behaviour depends on the metric type, following NOAA/NMFS guidance:

• SEL (time): The selected weighting curve is applied per frequency band before summing, consistent with the standard filterbank approach.
• SPL peak / peak-to-peak: No weighting is applied. Peak SPL is an unweighted (flat) metric under NOAA/NMFS guidance — the broadband peak pressure is reported directly.

See Solvers → Species Weighting in Time-Domain Solves for more detail.