Impact of Fishing and Stocking Practices on Coregonid Diversity

Abstract

Fish species diversity can be lost through interacting stressors including habitat loss, stocking and overfishing. Although a multitude of stressors have played a role in the global decline of coregonid (Coregonus spp.) diversity, a number of contemporary studies have identified habitat loss stemming from eutrophication as the primary cause. Unfortunately, reconstructing the role of fishing and stocking practices can be difficult, because these records are incomplete or appear only in hard-to-access historic grey literature. Based on an illustrative set of historic and contemporary studies, we describe how fisheries management practices may have contributed to coregonid diversity loss in European and North American lakes. We provide case studies examining how fishing and stocking may reduce coregonid diversity through demographic decline and introgressive hybridization. In some lakes, fisheries management practices may have led to a loss of coregonid diversity well before issues with habitat degradation manifested. Our review suggests that fish conservation policies could beneficially consider the relative importance of all stressors, including management practices, as potential drivers of diversity loss.

Does eutrophication-driven evolution change aquatic ecosystems?

“…Management strategies aiming to facilitate recovery from the effects of eutrophication on evolutionary dynamics must additionally consider other anthropogenic drivers of evolutionary change, such as harvesting-induced evolution [37,64], the effect of stocking with hatchery bred fish [65], pollution [66] and climate change [67].…”

Hydroacoustic Autonomous boat for Remote fish detection in LakE (HARLE), an unmanned autonomous surface vehicle to monitor fish populations in lakes

“…For the upper layer, the fish density was low, and no geographical pattern was observed. Conversely, in the cold-water deep layer, mainly individuals of whitefish (C. lavaretus), a cold stenotherm species, were detected (Anneville et al 2015). In this layer, the fish density that was estimated using the USV, and similarly using the boat, was considerably increased in the north part of Lake Aiguebelette, close to the main tributary.…”

Influence of warming temperatures on coregonine embryogenesis within and among species

“…A mechanistic understanding of thermal response from populations across latitudes will be essential to predict the vulnerability of species and populations to climate change. Additionally, stocking practices are important to consider, including supportive breeding, and may affect the adaptive potential of populations through an artificial selection process (Anneville et al, 2015; Christie et al, 2012; Ford, 2002) and their ability to respond to environmental changes.…”

“…Freshwater whitefishes, Salmonidae Coregoninae (hereafter coregonines), are of great socio-economic value (Ebener et al, 2008; Lynch et al, 2015, 2016; Nyberg et al, 2001; Vonlanthen et al, 2009, 2012), and are also considered to be critically sensitive to the effects of climate change because they are cold, stenothermic fishes (Elliott & Bell, 2011; Isaak, 2014; Jeppesen et al, 2012; Jonsson & Jonsson, 2014; Karjalainen et al, 2015; Karjalainen, Jokinen, et al, 2016; Stockwell et al, 2009). Coregonine fisheries worldwide have experienced population declines due to highly variable and weak year-class strengths (Anneville et al, 2015; Myers et al, 2015; Nyberg et al, 2001; Vonlanthen et al, 2012). In the 20th century, causes of decline included fishing and stocking practices (Anneville et al, 2015) and eutrophication causing poor incubation conditions (Müller, 1992; Vonlanthen et al, 2012).…”