Otter Research Ltd. (AD Model Builder & MULTIFAN)

This company offers two products: AD Model Builder and MULTIFAN. The former "is a tool for the rapid development and implementation of nonlinear statistical models." It is said to have a number of useful features: derivatives are calculated without intervention and very efficiently, the Hessian and covariance matrices are automatically available, etc. Programs, documentation, and a trial version are available here. The other product, MULTIFAN, "is used to estimate growth and mortality for fishes and other species using length frequency data." An advanced version, MULTIFAN-CL is now available as well.