We evaluated the relative performance of electrofishing and visual surveys (snorkeling) for estimating the abundance of combinations of fish species and size classes in rivers. We also assessed the effect of environmental conditions on potential differences between the results obtained using these two sampling methods. Sampling sites were distributed in the Laurentian region of Québec. Both methods were used while sections were blocked. Three snorkelers swam the river sections upstream while identifying and counting fish of each species and size classes. Three-pass electrofishing was performed in the same sites and abundances were estimated with a maximum likelihood depletion model. Greater abundances of fish were observed by snorkeling than by electrofishing at all sites. Snorkeling species richness was higher or equal to electrofishing richness in, respectively, 60 % and 40 % of sampled sites. Differences in the fish communities observed by both sampling methods were not related to environmental conditions. The results of our work are therefore contrary to that of most published studies that suggested the use of electrofishing over visual surveys. This study highlights that conclusions derived from previous work on sampling gear comparisons may not be generalisable; rather survey methods might benefit from being selected based on fish community composition.

Forage fish form a critical trophic link in marine ecosystems, and yet, for many species, there is limited information available. As nations move from single species stock assessments to ecosystem approaches to fisheries management (EAFMs), more information on forage fish will be required. In this study, 50 years of scientific literature were systematically mapped for 11 forage fish species in Canada’s Arctic, Atlantic, and Pacific oceans. The objectives were to identify 1) knowledge clusters and gaps and 2) the pressures studied in relation to forage fish outcomes. Of the 2897 articles mapped, the majority studied adults, and the distribution, productivity, growth and life history of commercially fished species. Knowledge gaps were identified for forage fish: 1) that were non-commercially exploited; 2) egg and larval life history stages of most species and juveniles of non-commercial species; 3) diets of most species; 4) migration and performance for all species, and survival of non-commercial species; and 5) the effects of some pressures (e.g., large-scale climate pressures). Addressing these knowledge gaps would improve the application of EAFMs.

Le présent article décrit les résultats d’inventaires et d’observations ichtyologiques réalisés dans la région de la Côte-Nord, Québec, au cours des mois d’août 2013 et 2014. Au total, 13 espèces de poissons ont été capturées, parmi lesquelles on trouve le méné ventre-citron (Chrosomus neogaeus), le méné à nageoires rouges (Luxilus cornutus), le méné à museau noir (Notropis heterolepis) et le mulet à cornes (Semotilus atromaculatus). Des recherches dans la littérature ichtyologique de même que dans les bases de données muséales et gouvernementales indiquent qu’il s’agirait de premières mentions ou d’extensions de l’aire de répartition de ces espèces sur la Côte-Nord. Une discussion est aussi présentée sur le potentiel qu’offrent les bases de données en ligne pour préciser l’aire de répartition connue de la faune aquatique du Québec.This article presents the results of ichtyological surveys and additional observations made in the Côte-Nord region of Québec in August 2013 and 2014. Thirteen fish species were caught, including the finescale dace (Chrosomus neogaeus), common shiner (Luxilus cornutus), blacknose shiner (Notropis heterolepis) and creek chub (Semotilus atromaculatus). Researches in the ichtyological literature as well as museum and governmental databases indicate that this is the first published record for these species northeast of the Saguenay River. A discussion on the usefulness of online databases to improve the knowledge of fish species distribution in Québec is also presented