Database on Natural Mortality Rates and Associated Life-History Parameters

Our article on the comparison of commonly applied empirical estimators of natural mortality, M, is now available online. Our analysis, based on data* from more than 200 fish species, showed that maximum age-based estimators are superior to estimators based on the von Bertalanffy growth parameters (K and Land water temperature. We recommend the use of M = 4.899 tmax−0.916 when an estimate for maximum age (tmax) is available and M = 4.118K0.73 L−0.33 otherwise.

Full citation: Then, A.Y., J.M. Hoenig, N.G. Hall and D.A. Hewitt. 2015. Evaluating the predictive performance of empirical estimators of natural mortality rate using information on over 200 fish species. ICES Journal of Marine Science 72 (1): 82-92. doi: 10.1093/icesjms/fsu136

CORRIGENDUM: In Then et al. (2015), the estimator referred to as Paulynls-T is intended for use with L in cm, not mm as stated. If L is in mm, the equation would be: M = 8.87 K0.73 L−0.33. We thank Dr. Nikolai Klibansky (US National Marine Fisheries Service, Beaufort, NC) for calling this error to our attention.

VIMS alumna Amy ThenWe created this database to facilitate studies of natural mortality rate and its relationship to life-history parameters. The database presently contains estimates of von Bertalanffy growth parameters, mean water temperature, and longevity, along with direct estimates of natural mortality rate of fish stocks. Citations are given for each parameter in the database so that investigators can make their own judgments as to which parameter estimates are “valid.”

This database will be maintained by a committee that

  1. oversees the acquisition of additional estimates,
  2. corrects errors in the database, and
  3. maintains a version control system so that the contents of each version of the database is documented.

Additional life-history parameters will also be added to the database.

Contributions to/suggestions for the database should be sent to

Important Links

1. Data used in Then et al. (2014) includes estimates of the instantaneous natural mortality M (year-1), the von Bertalanffy growth parameters, K (year-1),  and L (mm), maximum age tmax (year), and mean water temperature T (°C).

Please cite the following when using the database:

Then, A.Y., and J.M. Hoenig. 2015. Database on Natural Mortality Rates and Associated Life History Parameters, version 1.X. Available at:

2. Metadata

3. Technical report accompanying Then et al. (2014)

4. Reference citations for sources of estimates used for the dataset used in Then et al. (2014)*

5. Addition of M estimates (unique species only)

  • Work in progress

* Quality control of all data and relevant information used is important. Please inform us of any error or oversight on our part ( and [[v|hoenig]] ).