In June 2018, The Ecology and Evolutionary Ethology of Fishes Conference was held in Montreal, Quebec, Canada. Eva Bergman and Larry Greenberg from Karlstad University attended the conference, and participated in a symposium on the ecology of landlocked Atlantic salmon. You can read the abstracts from their talks here:

Conservation of landlocked salmon and trout in a regulated river – a holistic approach

Bergman, Eva; Calles, Olle; Greenberg, Larry; Hagelin, Anna; Norrgård, Johnny; Nyqvist, Daniel; Piccolo, John J

Populations of migratory salmon and trout have worldwide shown a decline due to human activities. Over the years numerous measures have been undertaken to maintain these populations, and conservation of migratory salmonids requires understanding of their ecology at multiple scales, combined with assessing anthropogenic impacts. The regulated River Klarälven and Lake Vänern host endemic populations of landlocked Atlantic salmon (Salmo salar) and brown trout (Salmo trutta). The historically high abundances of the salmonids in the River Klarälven in the early 1800s have decreased dramatically, reaching all-time lows after the completion of nine Swedish hydroelectric power stations in the 1960s. After an extensive stocking program and transportation of spawners past eight hydroelectric plants, catches from commercial, maintenance and sport fishing have again increased. Recently, increases in the proportion of wild salmon returning to the river have generated interest in establishment of wild salmon inhabiting the entire river, including upstream of the Norwegian border where they historically occurred. How well are we equipped to meet these new goals, taking into account our limited knowledge of the species’ different life stages, coordination between different actors involved in the conservation processes, and our skills to communicate and understand everybody’s role in this conservation process?

Post-spawning survival and downstream passage of landlocked Atlantic salmon in the regulated river Klarälven

Greenberg, Larry; Bergman, Eva; Calles, Olle; Hagelin, Anna; Nyqvist, Daniel

Repeat salmonid spawners may make large contributions to total recruitment and long term population stability. Despite their potential importance, little is known about this life stage for landlocked populations. Here, we studied post-spawning behaviour and survival of landlocked Atlantic salmon in relation to downstream dam passage in the River Klarälven, Sweden from 2011-14. Eight hydropower stations separate the feeding grounds in Lake Vänern from the spawning grounds in the river, and no measures to facilitate downstream migration are present. Nearly half of the salmon survived spawning and initiated downstream migration. Females and small fish had higher post-spawning survival than males and large fish. During years with high spill, 84% of the fish passed the first dam, mostly via upward-opening spill gates after a median delay of 25 min. During a year of low spill, 41% of the fish passed the dam, mostly through the turbines, where mortality was high. In addition, most fish approached the turbine intake near the surface. For all years combined, only 2% of the tagged fish successfully passed all eight hydropower stations to reach Lake Vänern. This result underscores the need for remedial measures to increase survival of downstream migrating kelts.

Access the conference program here.

Group photo from the landlocked Atlantic salmon symposium at the Ecology and Evolutionary Ethology of Fishes (EEEF) Conference 2018

Dirk Hattermann (Justus Liebig University Giessen), Markus Bernhardt-Römermann (Friedrich Schiller University Jena), Annette Otte (Justus Liebig University Giessen) and Lutz Eckstein (Karlstad University) recently published the paper “New insights into island vegetation composition and species diversity – Consistent and conditional responses across contrasting insular habitats at the plot-scale” in the scientific journal PLOS ONE.

In the abstract the authors write:

“Most island-ecology studies focus on the properties of entire island communities, thus neglecting species-environment relationships operating at the habitat-level. Habitat-specific variation in the strength and sign of these relationships will conceal patterns observed on the island scale and may preclude a mechanistic interpretation of patterns and processes. Habitat-specific species-environment relationships may also depend on the descriptor of ecological communities. This paper presents a comprehensive plot-based analysis of local vegetation composition and species diversity (species richness and species evenness) of (i) rocky shore, (ii) semi-natural grassland and (iii) coniferous forest habitats in three Baltic archipelagos in Sweden. To identify differences and consistencies between habitats and descriptors, we assessed the relative contributions of the variable-sets “region”, “topography”, “soil morphology”, “soil fertility”, “soil water”, “light availability”, “distance” and “island configuration” on local vegetation composition, species richness and species evenness. We quantified the impact of “management history” on the descriptors of local grassland communities by a newly introduced grazing history index (GHI). Unlike species diversity, changes in vegetation composition were related to most of the variable-sets. The relative contributions of the variable-sets were mostly habitat-specific and strongly contingent on the descriptor involved. Within each habitat, richness and evenness were only partly affected by the same variable-sets, and if so, their relative contribution varied between diversity proxies. Across all habitats, soil variable-sets showed highly consistent effects on vegetation composition and species diversity and contributed most to the variance explained. GHI was a powerful predictor, explaining high proportions of variation in all three descriptors of grassland species communities. The proportion of unexplained variance was habitat-specific, possibly reflecting a community maturity gradient. Our results reveal that species richness alone is an incomplete representation of local species diversity. Finally, we stress the need of including habitat-based approaches when analyzing complex species-environment relationships on islands.”

You can access the paper here.