Application of Generalized Depletion Model to Recruitment of American Eel Elvers and Empirical Support from Survey Data

Recruitment is one of the driving forces determining the population dynamics of a stock, and knowledge about recruitment is crucial in providing reliable results in modern stock assessment. The population of the American Eel Anguilla rostra is at risk, and the fisheries on the elvers are one threat for its persistence. We applied a generalized depletion model on the catch and effort data of the elver fishery of the East River, Chester, Nova Scotia, from 1996 to 2018. The elver fishery of the East River did not have high exploitation pressure on the elver waves passing through. The natural mortality rate varied substantially among years, with a mean generally in agreement with other studies. The estimates of the model parameters did not exhibit significant temporal trends. Moreover, the estimate of annual elver abundance matched well with the fishery‐independent abundance index, providing the first empirical support of the generalized depletion model. The generalized depletion model is an effective method to assess the exploitation status of elver fisheries, as well as providing an estimate of recruitment strength and natural mortality that can be used for stock assessment on the adult stocks when only fisheries‐dependent catch and effort data are available.