Savory cereal bars made with seed, fruit peel, and fish meal

Cereal bars are practical, popular, and represent a multicomponent food with market potential. This work aimed to develop tasty cereal bars with kabocha seeds (Cucurbita moschata), kabochapeels, pineapple peel (Ananassp.), and passion fruit peel (Passiflorasp.) with different levels of fishmeal, as nutritional enrichment. To this purpose, the fish meal was prepared with tilapia and salmon carcasses added to the basic ingredients of the bar. The fish concentrate levels used were 0% (control), 5%, 10% and 15%, amounting to four treatments, with five replications. The elaborated bars were analyzed for proximate compositional, sensory properties, and microbiological contamination. The resultsindicated high levels of protein (49.65%) and lipid (32.40%) for fishmeal. The inclusion of this concentrate in cereal bars interfered with their composition by increasing protein content and reducing the content of carbohydrates and caloric value. As forsensory properties, the average scores were around 6, which indicates that the panelists slightly liked the product. It can be concluded that the addition of up to 15% of tilapia fishmeal with salmon in savory cereal bars containing seed and fruit peel, improve their nutritional composition without adversely affecting their sensory quality.

Terrestrial and semi-aquatic scavengers on invasive Pacific pink salmon (Oncorhynchus gorbuscha) carcasses in a riparian ecosystem in northern Norway

Pacific pink salmon (Oncorhynchus gorbuscha) invasions, thought to originate from populations introduced and established in Russia, occurred along the Norwegian coast in 2017 and 2019. Despite several thousand pink salmon entering and establishing in northern Norwegian rivers, current understanding of the ecological effect of the species in northern Europe is limited. Scavengers feeding on pacific salmon carcasses are important vectors for the transport of marine derived energy and nutrients to terrestrial ecosystems in the Pacific Northwest, North America, where the salmon naturally occur. However the role of terrestrial and aquatic scavengers in the consumption and removal of pink salmon beyond the salmon’s native range is unknown. This study has identified terrestrial and sub-aquatic vertebrate scavengers on pink salmon carcasses in a sub-arctic river in northern Norway. Avian scavengers filmed by a camera placed near sites baited with pink salmon carcasses included the Eurasian magpie (Pica pica), hooded crow (Corvus cornix), common raven (Corvus corax), the European herring gull (Larus argentatus), redwing (Turdus iliacus) and goosander (Mergus merganser). However, the largest carcass weight was removed by red foxes (Vulpes vulpes). Carcasses entering Vesterelv River in 2019 were estimated to provide energy and nutrients to the river ecosystem an order of magnitude lower than in the Pacific Northwest. This study provides some of the first information in northern Europe on the mechanisms and quantification of energy and nutrient transfer from the ocean to riparian environments via introduced Pacific pink salmon. Results help to begin to determine the ecological effect of pink salmon and the development of appropriate management strategies.

Can nutrient additions facilitate recovery of Pacific salmon?

Multiple restoration actions have been implemented in response to declining salmon populations. Among these is the addition of salmon carcasses or artificial nutrients to mimic marine-derived nutrients historically provided by large spawning runs of salmon. A key assumption in this approach is that increased nutrients will catalyze salmon population growth. Although effects on aquatic ecosystems have been observed during treatments, it is unclear whether permanent population increases for salmon will occur. To test this assumption and address associated uncertainties, we linked a food web model with a salmon life cycle model to examine whether carcass additions in a river reach would improve conditions for salmon in the long term. Model results confirmed immediate increases in the biomass of periphyton, macroinvertebrates, and fish during carcass additions. In turn, juvenile salmon grew larger and experienced improved freshwater and smolt survival, which translated to a greater number of adults returning to spawn. However, once additions ceased, salmon abundance returned to pretreatment levels, which, based on our model, is owing to a combination of instream and out-of-basin factors. Overall, results of this work suggest that benefits during carcass and nutrient additions may not translate into persistent productivity of salmon unless additions are sustained indefinitely or other limiting factors are addressed.

Salmon carcasses influence genetic linkages between forests and streams

Biodiversity at many scales (functional group, species, genetic) can result in emergent ecological patterns. Here we explore the influence of tree genotypic variation and diversity on in-stream ecosystem processes and aquatic communities. We test whether genetically diverse inputs of leaf litter interact with a keystone organism, anadromous salmon, to influence in-stream ecosystem function. We used reach-level manipulation of salmon carcasses and leaf litter bags to examine how nutrient inputs interact with genetic variation in leaf litter decomposition. Genotypic variation in black cottonwood (Populus balsamifera ssp. trichocarpa) significantly influenced leaf litter chemistry, litter mass loss, and fungal biomass, but these variables were only weakly influenced by salmon carcass presence or a genotype × salmon (G × E) interaction. Mixtures of genotypes tended to demonstrate antagonistic effects (slower than expected decomposition) in the absence of salmon, but synergistic effects (faster than expected decomposition) when salmon were present. Our findings suggest that the influence of plant genotypic variation in linking aquatic and terrestrial ecosystems may be altered and in some cases intensified in the presence of a keystone vertebrate species.