Search

Freshwater ecosystems and the fisheries they support are increasingly threatened by human activities. To aid in their management and protection, we outline nine key principles for supporting healthy and productive ecosystems based on the best available science, including laws of physics and chemistry apply to ecology; population dynamics are regulated by reproduction, mortality, and growth; habitat quantity and quality are prerequisites of fish productivity; connectivity among habitats is essential for movements of fishes and their resources; freshwater species and their habitats are tightly linked to surrounding watersheds; biodiversity can enhance ecosystem resiliency and productivity; global processes affect local populations; anthropogenic stressors have cumulative effects; and evolutionary processes can be important. Based on these principles, we provide general recommendations for managing and protecting freshwater ecosystems and the fisheries they support, with examples of successful implementation for each strategy. Key management strategies include engage and consult with stakeholders; ensure that agencies have sufficient capacity, legislation, and authority to implement policies and management plans; define metrics by which fisheries resources and management success or failure will be measured; identify and account for threats to ecosystem productivity; adopt the precautionary approach to management; embrace adaptive management; implement ecosystem-based management; account for all ecosystem services provided by aquatic ecosystems; protect and restore habitat as the foundation for fisheries; and protect biodiversity. Ecosystems are complex with many intertwined components and ignoring linkages and processes significantly reduces the probability of management success. These principles must be considered when identifying management options and developing policies aiming to protect productive freshwater ecosystems and sustainable fisheries. Key words: biodiversity, connectivity, cumulative effects, global processes, habitat, watershed. Les ecosystemes d'eau douce et les pecheries qu'ils supportent sont de plus en plus menaces par les activites humaines. Afin d'aider leur amenagement et leur protection, les auteurs etablissent neuf principes de base pour supporter des ecosystemes productifs et en sante, bases sur les meilleures connaissances disponibles, incluant les lois de la physique et de la chimie appliquees a l'ecologie; la dynamique des populations est regulee par la reproduction, la mortalite et la croissance; la quantite et la qualite des habitats constituent des prealables pour la productivite du poisson; la connectivite entre les habitats est essentielle pour les mouvements des poissons et de leurs ressources; les especes d'eau douce et leurs habitats sont etroitement relies aux bassins versants environnants; la biodiversite peut augmenter la resilience et la productivite des ecosystemes; les processus globaux affectent les populations locales; les agents stressants anthropogenes exercent des effets cumulatifs; et, les processus evolutifs peuvent etre importants. Bases sur ces principes, les auteurs proposent des recommandations generales pour l'amenagement et la protection des ecosystemes d'eau douce et des pecheries qu'ils supportent, avec des exemples de mises en place reussies de plans d'amenagement pour chaque strategie. Les strategies determinantes incluent : l'engagement et la consultation avec les parties prenantes; l'assurance que les agences ont la capacite, la legislation et l'autorite suffisantes pour mettre en oeuvre les politiques et les plans d'amenagement; la definition metrique par laquelle seront mesures les succes ou les echecs des ressources et de l'amenagement des pecheries; l'identification et la prise en compte des menaces a la productivite des ecosystemes; l'adoption de l'approche par precaution dans l'amenagement; viser l'amenagement adaptatif, mettre en place l'amenagement base sur l'ecosysteme; tenir compte de tous les services ecosystemiques fournis par les ecosystemes aquatiques; proteger et restaurer l'habitat en tant que base des pecheries; et proteger la biodiversite. Avec plusieurs composantes inter reliees, les ecosystemes sont complexes et l'ignorance des liens et des processus reduit significativement la probabilite du succes de l'amenagement. Ces principes doivent etre consideres lorsque l'on identifie des options d'amenagement et definit des politiques visant a proteger les ecosystemes d'eau douce productifs pour des pecheries durables. [Traduit par la Redaction] Mots-cles: biodiversite, connectivite, effets cumulatifs, processus globaux, habitat, bassin versant., Introduction Freshwater ecosystems are among the most imperiled on Earth (Richter et al. 1997; Strayer and Dudgeon 2010), with extinction rates of freshwater fauna higher than for many other ecosystems [...]

Abstract: Radiocarbon generated by atmospheric testing of nuclear weapons (bomb radiocarbon) produced a strong signal with an abrupt onset in the 1950s, which serves as a dated marker for tracing [...]

Abstract: A key requirement of effective fisheries management is a better understanding of the mechanisms driving recruitment variability. Recent research suggests that the quantity and quality of gametes produced by [...]

It has been established that the use of stable isotopes can give time-integrated and energy-based depictions of food-web structure. In this research, stable isotope ratios were used to assess the food-web repercussions of the invasion of smallmouth bass and rockbass into Canadian lakes. This work supports other research showing that subsidies of resources from other systems or habitats can be both energetically significant and important in food-web dynamics.

The American eel (Anguilla rostrata) occupies a vast range in the West Atlantic Ocean and inflowing waters. Despite its presumed panmictic status, management of this species is geographically fragmented. There have been widespread calls for internationally coordinated efforts towards a range-wide stock assessment, but such an objective faces obstacles of a high degree of heterogeneity in major life history characteristics and the near-absence of such data in the northern, western, and southern parts of the species' range. This paper reviews novel and underutilized methods and data sources that may aid progress to an eventual range-wide assessment. Methods for obtaining information on distribution and abundance include mining of extant data and field surveys by glass bottom boat, electrofishing boat, net enclosures, environmental DNA (eDNA) and ocean larval tows. Analytic resources and tools include environmental databases, fetch as a covariate of abundance, accounting for the net effects of small ponds, GIS-oriented habitat modeling, glass eel-oriented population modeling, estimation of age structure from length structure, use of life history parameter clines to fill gaps in assessment input values, and life cycle modeling. eDNA is a cost-effective technique that has the potential to clarify American eel distribution, and possibly relative abundance, over the very large areas where data for this species are sparse. Most other techniques reviewed in this paper have substantial costs, which may constrain their use in the southern part of the American eel range where resources of aquatic science are often limited. [ABSTRACT FROM AUTHOR]