Aquatic ecosystems in change: capturing the impacts of fishing and environmental stressors by utilising ecological network theory

Abstract

Understanding how wild populations respond to multiple environmental stressors, and how they recover following depletion, is fundamental to conservation biology and the sustainable use of resources. Fisheries represent a major scale system of human-induced mortality in natural populations (1). The theory of density-dependent population growth suggests that at a low abundance populations should grow at a fast rate, yet in reality many stocks fail to recover even after large reductions in fishing pressure (2).

The freshwater salmonid vendace (Coregonus albula), is an important target of freshwater fisheries in the Nordic countries. Here, we will utilise the Allometric Trophic Network (ATN) modelling framework (3) to explore the dynamics of a vendace population subjected to fishing in a typical Central Finnish lake. The model will investigate the life history changes induced by fisheries, and describe how those changes may feed back to the entire ecosystem through species interactions, ecosystem stability, and resilience against disturbances.

This poster will describe how life history changes may affect the ability of a fish population to sustain fishing and recover from overfishing. Resolving life history dynamics will ultimately help us gain a better understanding of how fishing could be conducted in a sustainable manner while accounting for the impact of multiple stressors at once.

(1) Darimont CT, Fox CH, Bryan HM et al. (2015) The unique ecology of human predators. Science 349:858-860 (2) Hilborn R &Walters C (1992) Quantitative fisheries stock assessment. Choice, Dynamics and uncertainty. Chapman and Hall, New York (3) Brose U, Williams RJ, Martinez ND. (2006) Consumer-resource body-size relationships in natural food webs. Ecology 87:2411-2417