Salmon Farming Research Articles

Long-term substitution of fish oil with alternative sources in Atlantic salmon (Salmo salar): Performance, health, and consumer appeal

Salmon farming in Chile faces the dual challenge of maintaining growth while improving sustainability. One approach to advance sustainability involves the feeds without marine-fishery inputs. This study aimed to evaluate the effect of completely replacing fish oil (FO) on the performance of Salmo salar throghout marine grow-out. The investigation involved fish ranging from 400 g to 4000 g and explored three diets without fish meal, each which included 2.2% EPA + DHA from different sources: FO (control), transgenic canola oil (Can n-3) and Schizochytrium sp. oil (AOV) as unique type of oils. Each diet was randomly distributed in triplicate among nine tanks with a recirculation system maintained at 12 °C, with automatic feeding and a 24-h light photoperiod. Fish density was 29 fish m−3 at day 133 of the experiment and seven fish m−3 at day 319. The diets were isoproteic, isolipidic and isoenergetic. Fish were evaluated at 133 and 319 days of experiment in terms of productive performance, liver health, EPA + DHA and lipid retention efficiency, fatty acid metabolism, response to acute stress, and final product quality. The results showed similar productive performance and liver health among the three diets during both sampling periods. No differences were observed in lipid or EPA + DHA retention efficiency in the whole body or fillet. Eicosanoids and receptors for anti-inflammatory mediators derived from EPA and DHA showed similar or higher capacities in fish fed with Can n-3 and AOV than those fed FO. Responses to induced stress, measured through lactate, cortisol, sodium, potassium, chloride, glucose, and the liver profile were similar between the three diets. Similarly in fillet quality between the three diets. However, sensory analysis revealed a lower intensity of “global aroma” in Can n-3-fed fish fillets and lower evaluations in “typical salmon aroma”, “oily aroma” and “fresh flavor” in AOV-fed fish fillets when they are compared with FO. The nutritional indicators of the final product were similar between the three diets, except for PUFA/SFA, the thrombogenicity index, hypercholesterolemia/hypocholesterolemia, and the health promotion index. In these specific indicators, fish fed with Can n-3 and AOV demonstrated more favorable results for consumer health than the FO-fed fish.

Enzyme-treated microalgal co-product diets for rainbow trout aquaculture: Supporting fish growth, phosphorus digestibility, and reducing phosphorus waste emission

Aquaculture is one of the fastest-growing food sectors, producing almost 50% of fish for human consumption worldwide. However, relying on fish meal and oil for aquaculture diets is not sustainable economically or environmentally. Aquaculture feeds also contain terrestrial plant ingredients with indigestible forms of phosphorus (P), of which 70%–80% can be released into aquatic environments. This P influx contributes to eutrophication of freshwater ecosystems that can lead to anoxic conditions. This study explores a more sustainable diet for salmonids, an important and valuable seafood. Our aim was to test ingredients with highly digestible forms of P in nutritionally balanced portions to support fish growth and reduce P loading. We determined the digestibility of three feeds containing raw, extruded, and enzymatically processed microalgal co-product of Nannochloropsis oculata compared to a conventional diet. We also quantified how much P was retained and excreted. We detected highest growth in trout fed enzymatically processed co-product feed, though it was not statistically different (p = 0.846) from growth of fish fed the reference or other co-product diets. The enzyme-treated, microalgal co-product ingredient and diet had comparable values for P digestibility and solid P excretion to the reference diet, but the lowest average solid P excretion of all test diets. Trout fed the enzyme-treated diet had the highest P retention, while the reference diet had the lowest (p = 0.0429). Trout fed the enzyme-treated diet had the lowest (p = 0.0174) and negative dissolved P excretion, while those fed the reference diet had the highest. Results showed that enzyme-treated N. oculata co-product maintains digestibility, increases P retention, and reduces dissolved P excretion compared to the reference diet in rainbow trout. These findings encourage follow-up research to design and test growth performance of diets containing enzyme-treated microalgal co-product as sustainable trout aquafeed.

Predicting regional cumulative effects of future development on coastal ecosystems to support Indigenous governance

Abstract To achieve better biodiversity outcomes and match local governance capacity, cumulative effects assessment frameworks that combine Indigenous and western knowledge to predict future development impacts on biodiversity are needed. We developed a spatial future‐focused model informed by inclusive elicitation and strategic foresight to assess the regional cumulative effects of development on ecosystem health across the land and sea. We collaborated with three First Nations on the Central Coast of British Columbia, Canada, enabling Indigenous priorities, knowledge and values to drive the process, from the choice of priority ecosystem components (including salmon, herring, seabirds and bears), to identifying future development scenarios (based on forestry, energy/mining, tourism and salmon aquaculture sectors). Bayesian networks were populated with empirical data and expert judgement elicited from knowledge holders to predict the cumulative effects of current and future pressures on species and ecosystems. Under current conditions, the lowest probability of persistence was predicted for Pacific salmon (37%), followed by Pacific herring (43%). Under future conditions, the greatest declines in species health were associated with the intense development of mining, tourism and forestry, with up to a 54% decline from the current baseline health estimates predicted for Marbled Murrelets and old‐growth forest. Future outcomes for overall ecosystem health were predicted to be worst in scenarios with high future forestry activities (>60% decline in some areas). The continuation or development of all four industries resulted in an 8% decline overall in ecosystem health across the Central Coast. In contrast, predicted ecosystem health in the tourism economy scenario increased up to 15% in some marine areas, primarily driven by the removal of salmon aquaculture and forestry activities. Synthesis and applications. Our study demonstrates an inclusive, regional approach to assessing the cumulative effects of future development on coastal species. The novel participatory tools and predictive framework draw upon and interweave multiple forms of knowledge, enabling Indigenous values to drive the process, and appropriately integrate Indigenous knowledge into regional cumulative effects assessment. Our interactive web application provides First Nations partners access to all outputs, supporting Indigenous‐led governance and in situ ecosystem‐based management of their lands and water.

An aquaculture risk model to understand the causes and consequences of Atlantic Salmon mass mortality events: A review

AbstractMass mortality events (MMEs) are defined as the death of large numbers of fish over a short period of time. These events can result in catastrophic losses to the Atlantic salmon aquaculture industry and the local economy. However, they are challenging to understand because of their relative infrequency and the high number of potential factors involved. As a result, the causes and consequences of MMEs in Atlantic salmon aquaculture are not well understood. In this study, we developed a structural network of causal risk factors for MMEs for aquaculture and the communities that depend on Atlantic salmon aquaculture. Using the Interpretive Structural Modeling (ISM) technique, we analysed the causes of Atlantic salmon mass mortalities due to environmental (abiotic), biological (biotic) and nutritional risk factors. The consequences of MMEs were also assessed for the occupational health and safety of aquaculture workers and their implications for the livelihoods of local communities. This structural network deepens our understanding of MMEs and points to management actions and interventions that can help mitigate mass mortalities. MMEs are typically not the result of a single risk factor but are caused by the systematic interaction of risk factors related to the environment, fish diseases, feeding/nutrition and cage‐site management. Results also indicate that considerations of health and safety risk, through pre‐ and post‐event risk assessments, may help to minimize workplace injuries and eliminate potential risks of human fatalities. Company and government‐assisted socio‐economic measures could help mitigate post‐mass mortality impacts. Appropriate and timely management actions may help reduce MMEs at Atlantic salmon cage sites and minimize the physical and social vulnerabilities of workers and local communities.

Trans-Atlantic genomic differentiation and parallel environmental and allelic variation in Lumpfish (Cyclopterus lumpus)

Abstract In marine species with large populations and high dispersal potential, large-scale genetic differences and clinal trends in allele frequency can provide insight into the evolutionary processes that shape diversity. Lumpfish, Cyclopterus lumpus, is found throughout the North Atlantic and has traditionally been harvested for roe and more recently used as a cleaner fish in salmon aquaculture. We used a 70 K SNP array to evaluate trans-Atlantic differentiation, genetic structuring, and clinal variation across the North Atlantic. Basin-scale structuring between the Northeast and Northwest Atlantic was significant, with enrichment for loci associated with developmental/mitochondrial function. We identified a putative structural variant on chromosome 2, likely contributing to differentiation between Northeast and Northwest Atlantic Lumpfish, and consistent with post-glacial trans-Atlantic secondary contact. Redundancy analysis identified climate associations both in the Northeast (N = 1269 loci) and Northwest (N = 1637 loci), with 103 shared loci between them. Clinal patterns in allele frequencies were observed in some loci (15%—Northwest and 5%—Northeast) of which 708 loci were shared and involved with growth, developmental processes, and locomotion. The combined evidence of trans-Atlantic differentiation, environmental associations, and clinal loci, suggests that both regional and large-scale potentially-adaptive population structuring is present across the North Atlantic.

Determination of water characteristics of trout farms for organic farming in Feke

Organic aquaculture represents a comprehensive approach to farm management and food production. It integrates the best environmental practices, promotes biodiversity conservation, preserves natural resources, and places a strong emphasis on ensuring the well-being of the fish, all in alignment with the preferences of discerning consumers. In this study, water quality and suitability of two different trout production enterprises in Feke/Adana city in Turkey for organic fish culture was investigated. The water quality parameters evaluated include temperature, dissolved oxygen, pH, Ca, Mg, Na, K, alkalinity, nitrate nitrogen, nitrite nitrogen, ammonium nitrogen, orthophosphate phosphorus, and alkalinity. It is seen that the head waters have a high water quality standard in terms of all their physical and chemical properties.

Design of a floating cage prototype with organic waste collector (food remains and excreta), produced by trout farming in lake Titicaca, Perú

InLake Titicaca, Peru, trout farming in floating cages has been a valuable opportunity for Andean residents, offering food and self-employment. However, this method has generated environmental problems by contaminating the bottom of the lake with large amounts of organic waste, such as excreta and remains of balanced feed. To address this challenge, a floating cage prototype was designed with an integrated organic waste collector, along with a vertical static settler and pump system. The objective of the research work was to mitigate the pollution of Lake Titicaca caused by the consumption of balanced feed in trout farming. A collecting cage model was built that trapped a significant amount of organic waste. 7 600 rainbow trout weighing an average of 800 g were used, fed with 300kg day-1of balanced feed ad libitum for 30 days. After 16 hours from the feed supply, an average accumulation of organic waste of 6.9 ± 0.98 kg day-1was observed, which was transported to the settler using an electric pump. A water quality analysis was carried out, finding values of total phosphorus (TP) of 1.316 ± 0.059 mg L-1, total nitrogen (TN) of 0.013 ± 0.001 mg L-1 and total organic matter (MOT) of 55.60 ± 0.30 mg L-1. L in the water column in the growing area. In conclusion, the design of the collecting cage proved to be an effective alternative to avoid the accumulation of organic waste at the bottom of the lake, and the recovered waste can be used as agricultural fertilizer, adding value to the process.

Insights from Hi-C data regarding the Pacific salmon louse (Lepeophtheirus salmonis) sex chromosomes.

Salmon lice, Lepeophtheirus salmonis (family Caligidae), are ectoparasites that have negatively impacted the salmon aquaculture industry and vulnerable wild salmon populations. Researchers have studied salmon lice to better understand their biology to develop effective control strategies. In this study, we updated the chromosome-level reference genome assembly of the Pacific subspecies of L. salmonis using Hi-C data. The previous version placed contigs/scaffolds using an Atlantic salmon louse genetic map. By utilizing Hi-C data from Pacific salmon lice, we were able to properly assign locations to contigs/scaffolds previously unplaced or misplaced. This resulted in a more accurate genome assembly and a more comprehensive characterization of the sex chromosome unique to females (W). We found evidence that the same ZW-ZZ mechanism is common in both Atlantic and Pacific subspecies of salmon lice using PCR assays. The W chromosome was approximately 800 kb in size, which is ∼30 times smaller than the Z chromosome (24 Mb). The W chromosome contained 61 annotated genes, including 32 protein-coding genes, 27 long noncoding RNA (lncRNA) genes, and 2 pseudogenes. Among these 61 genes, 39 genes shared homology to genes found on other chromosomes, while 20 were unique to the W chromosome. Two genes of interest on the W chromosome, prohibitin-2 and kinase suppressor of ras-2, were previously identified as potential sex-linked markers in the salmon louse. However, we prioritized the 20 unique genes on the W chromosome as sex-determining candidates. This information furthers our understanding of the biology of this ectoparasite and may help in the development of more effective management strategies.

Assessing Consumer Implications of Reduced Salmon Supply and Environmental Impact in North America

This study investigates the impact of the Canadian government’s decision to reduce the supply of farm-raised salmon in British Columbia (BC) on domestic prices, the level of imports, and the environment. By drawing upon data from diverse sources, this study employs the SARIMAX model to forecast future trends in salmon prices up to 2026. The forecasted results reveal that retail salmon prices will exhibit greater unpredictability and a predicted price increase of over CAD 30 per kilogram by 2026. In addition, increased consumption of imported salmon due to BC farm closure is expected to contribute to heightened carbon emissions and result in job losses within rural and indigenous communities. In short, BC salmon farm closure carries profound consequences for both the environment and market dynamics.

Effects of aquaculture effluents on the slender sea pen Virgularia mirabilis

This study aims to assess in situ the impact of effluents originating from an Atlantic salmon (Salmo salar) farm on a nearby slender sea pen (Virgularia mirabilis) field. We evidenced (1) the presence and persistence of emamectin residues (i.e. a common chemotherapeutants used for treating ectoparasites in salmons) in V. mirabilis tissue 56 days after treatment and (2) lethal and sublethal responses of V. mirabilis to effluents discharged by the salmon farm. Particularly, sea pens near the fish farm exhibited significant overproduction of mucus, contraction of polyps’ tentacles, and disappearance of associated fauna. Furthermore, sea pens located directly underneath the farm showed substantial tissue necrosis and, in the most severe case, complete tissue loss and mortality. Our results suggest that lethal damages on sea pens occur directly below the farm, and that sublethal effects are visible up to 500 m from the farm. However, the presence of V. mirabilis below the studied farm, which has been active for more than twenty years, suggests that V. mirabilis population possesses the capacity to recover from the impacts of the farm, thereby preventing the complete disappearance from the area. In this context, it would be particularly interesting to run a temporal survey following the health state of V. mirabilis during an entire production cycle to have a more precise overview of fish farm impacts on this species, including during and after the post-production fallowing period.

Assessing the environmental impacts of conventional and organic scenarios of rainbow trout farming in France

In France, rainbow trout farming in conventional flow-through systems raises environmental concerns. To address this, there is a growing interest in organic aquaculture. In this study, we employed an attributional life cycle assessment (LCA) to analyze the environmental impacts of rainbow trout production, comparing conventional and organic practices in a model fish farm. Our life cycle impact assessment revealed that organic farming significantly reduced environmental impacts per tonne of trout in seven of the nine selected impact categories. Notably, freshwater ecotoxicity exhibited the most significant difference, with organic systems showing a 35% decrease. The only exceptions were freshwater eutrophication and water dependence, where organic production led to higher impacts per tonne of trout. In conventional farming, emissions amounted to 14 kg of P eq./tonne, whereas in organic farming, the emissions were slightly higher (15 kg of P eq./tonne). For water dependence, one tonne of trout production in the conventional system mobilized 128 103 m3 vs. 185 103 m3 in the organic system. The environmental benefits of organic production were even more marked when using a surface-based functional unit (m2y). We demonstrated the benefits of organic trout production from an environmental perspective. However, our findings highlight the caution needed when interpreting LCA comparisons of such production systems that can be highly influenced by methodological choices such as the functional unit used.

Catch my drift? Between-farm dispersal of biofouling waste from salmon pen net cleaning: Potential risks for fish health

Biofouling is a serious challenge for global salmon aquaculture and farmers have to regularly clean pen nets to avoid impacts on stock health and farms' structural integrity. The removed material is released into the surrounding environment. This includes cnidarian species such as hydroids, whose nematocyst-bearing fragments can impact gill health and fish welfare. There is also increasing evidence of the association of parasites and pathogens with biofouling organisms and cleaning fragments. It is unknown whether and how far local current regimes disperse biofouling material and whether this material reaches and interacts with adjacent pens or even neighbouring farms downstream, or wild fish populations in surrounding environments.We focussed on the cnidarian hydroid Ectopleura larynx, one of the most abundant biofouling species on Norwegian aquaculture installations. Using a 3D hydrodynamic model parameterised with physical and biological properties of hydroid particles (derived via field and laboratory studies), we simulated the dispersal of net cleaning waste from two Norwegian salmon farms.Our results demonstrate that net cleaning waste is extensively dispersed throughout neighbouring pens, and even to adjacent aquaculture facilities. Salmon were exposed to concentrations of biofouling particles up to 41-fold elevated compared to background concentrations, and for up to 30.5 h. Maximum dispersal distance of hydroid particles was 5.5 km from the point of release, achieved largely within 48 h. Least-cost distance calculations show that this distance exceeds the nearest-neighbour distance of 70 % of Norway's salmon farms (654 farms).Our study provides some evidence that actions taken to manage biofouling at salmon farms may affect neighbouring farms and surrounding natural environments. The results highlight the potential risks associated with net cleaning: the dispersal of harmful cnidarian particles, associated pathogens, and non-indigenous species, thus underlining the need for novel farming or net cleaning technologies that prevent the release of potentially harmful cleaning waste.

The Species Composition and Prevalence of Thorny-Headed Worms (Acanthocephala: Echinorhynchidae, Neoechinorhynchidae and Pomphorhynchidae) in Trouts, Complex Measures to Control Them in Fish Farms in the Territory of Azerbaijan Republic

During period 2015-2020 spreading of acanthocephaliasis in the rainbow and brown trout in the fish breeding farms of Azerbaijan Republic was studied. Totally, from 668 fish examined specimens 430 (64.37%) were infected. Correlation of data on the extensiveness and intensity of invasion by thorny-headed worms (Acanthocephala) in trout farms is ventured to make an assumption about unfavorable epidemiological situation in trout breeding farms of the Republic of Azerbaijan. For the purpose of control acanthocephaliasis in trout, a number of drugs were used. The most effective drug was Tetramizole-20%, which was adopted in the trout farms.

Evaluation of novel PCR-based method to assess gill injuries in fish caused by the cnidarian Ectopleura larynx

Gill disease is a major threat to aquaculture of Atlantic salmon, with an unknown and likely underestimated contribution from cnidarians such as jellyfish and biofouling hydroids. To better understand the risk and thus enable mitigation, technology for the certain identification of cnidarian-related gill damage is needed. We used the hydroid Ectopleura larynx in a case study to determine whether the exposure of salmon to nematocyst-bearing hydrozoans can be deducted via non-destructive PCR-based methods. In a field experiment, we evaluated (i) whether swabbing the inside of the gill operculum in farmed Salmo salar and subsequent PCR analysis can provide quantifiable information about the presence of E. larynx material in the gill chamber and, if so, (ii) whether the screening results correlate with histological assessments of gill damage. The developed PCR methods were able to detect the presence of biofouling hydroids in ambient water. However, despite exposure to suspended hydroid particle concentrations that did result in gill damage in some salmon, quantitative PCR results did not correlate with histological gill assessments. For opercular swabs to serve as a diagnostic tool for detecting biofouling-mediated gill damage in live salmon, increased specificity of genetic markers and improved sampling methods are needed.Animal trial permit no. 24252 (granted 06.07.2020, Norwegian Food Safety Authority).

Seasonal Mortality of Wild Atlantic Menhaden (Brevoortia tyrannus) Is Caused by a Virulent Clone of Vibrio (Listonella) anguillarum; Implications for Biosecurity along the Atlantic Coastal United States

Atlantic menhaden are a highly migratory marine species in the Eastern United States that suffer from seasonal chronic mortality. Affected fish show neurologic signs referred to as spinning disease, including circling at the surface and erratic corkscrew swimming before death. We investigated three similar menhaden mortality events consistent with spinning disease in coastal New Jersey and New York between 2020 and 2021 to understand the cause. A unique strain of Vibrio (Listonella) anguillarum (serogroup O3) was detected regularly in high loads, particularly in the brains of moribund fish, by both metagenomics and bacterial isolation. The most common histopathological changes in moribund fish were hemorrhagic meningitis, encephalitis, pyknosis, and karyorrhexis of hematopoietic tissues in the kidney and spleen. Whole genome sequencing of isolates from moribund fish representing a wide spatial and temporal range showed that they were nearly identical clones, suggesting it to be a pathogenic strain circulating in the population. Though V. anguillarum is believed to be the main pathogen associated with spinning disease and mortality, Yersinia ruckeri (serotype O1) was isolated from smaller numbers of fish. Considering the highly migratory nature of Atlantic menhaden throughout the eastern United States and their use as bait for other fisheries, these findings identify potential biosecurity challenges that should be considered in Atlantic salmon aquaculture, fisheries, and emerging marine aquaculture in the region.

What affects the level of local social acceptance of salmon farming in Norway?

The concept of a social licence to operate (SLO) that first emerged related to mining has been developed into several strands of theoretical models and used to study the social acceptance of industries in different contexts. There is an emerging literature on SLO for salmon-farming, but very few quantitative analyses are done to identify and assess factors that affect the level of social acceptance. Models that explain social acceptance levels from people's trust in an industry or company, their confidence in governance, and views on procedural and distributional fairness (trust models) are designed for quantitative analysis, and they have been successful in explaining social acceptance levels for mining. In this paper, we use survey data to test whether the factors in trust models can also explain the level of local social acceptance for salmon farming in Norway. From the structural equation modelling analysis, we conclude that these models at best have limited explanatory power in our case. We then develop an alternative model to analyse social acceptance, where factors of perception and attitudes and respondents' individual characteristics are tested as direct regression paths to influence level of acceptance. This model explains the variation in the data well. The factors that most strongly affect the level of acceptance, and which industry or authorities also can influence, are the perception of to what degree aquaculture is environmentally sustainable, whether the industry acts according to society's expectations, and if the industry is trustworthy. Practical implications for the industry and governance are discussed.

Spatio-temporal variations in the mesozooplankton assemblages off Clarence Island, Magellan Strait, Chile

The seasonality in the light regime from subpolar regions impinges on limitations in the zooplankton dynamics. However, knowledge about seasonal variations in the mesozooplankton assemblages is limited in the southern tip of South America and around the Magellan Strait. Here, we studied the seasonal variation (summer vs. winter) and the spatial distribution (dozens of kilometers) of the mesozooplankton on the occidental shore of Clarence Island, Magellan Strait, Chilean Patagonia. A total of 69 taxonomic groups were identified in the samples, varying from 65 in summer (early March 2020) to 50 in winter (June 2020). Copepods numerically dominated the plankton, particularly Drepanopus forcipatus and Clausocalanus brevipes, although chaetognaths were also abundant in winter. The similarity in the composition was higher for samples collected in summer, whereas in winter there was larger variability in the zooplankton structure. At spatial scale, a large sound at the eastern coast of the island, Dyneley sound showed different composition of copepods compared to other channels both in summer and winter. Seasonal variation was five times larger than the spatial variation in the similarity of the mesozooplankton composition. Finally, higher richness and lower evenness were detected in austral summer, while the opposite was noticed in winter, with differences in alpha-diversity indices between seasons but not among locations. Understanding the drivers of seasonal variability in the zooplankton composition of this extreme ecosystem is essential for predictions of the impacts of salmon farming and climate change in southern Patagonia.

Sludge from sea-based Atlantic salmon (Salmo salar L.) production: quantification, composition, and potential application in integrated multi-trophic aquaculture

Future growth of Atlantic salmon (Salmo salar L.) in Norway is tied to finding solutions for major ecological challenges connected to salmon lice, escapees, and nutrient emissions from sea cages. At the same time, nutrient-rich sludge from salmon production comprises a valuable resource for the cultivation of lower trophic species using an integrated multi-trophic aquaculture (IMTA) approach. This study aimed to quantify the sedimentation of aquaculture sludge under sea cages of an Atlantic salmon aquaculture site and to qualify the composition of this sludge. Additionally, the study evaluated the hypothetical use of sludge from sea-based aquaculture as a feed source for polychaetes Hediste diversicolor. Using sediment traps, sludge samples were collected under two different Atlantic salmon sea cages, at two different depths, and three different sampling dates. Subsequently, they were quantified, and their composition was assessed with regards to carbon (C), nitrogen (N), phosphorus (P), lipid, fatty acid (FA), protein, amino acid (AA), and ash content as well as elemental ratios and composition of FAs and AAs. The quantity of collected sludge was significantly different between sea cages, with a strong positive correlation between feed input and collected sludge (R2 = 0.98, p < 0.05). Sampling depth did not affect the quantity of collected sludge in the sediment traps (2215 ± 480 mg DW day−1), and no significant difference in sedimented sludge as a proportion of theoretically produced sludge (12.94 ± 2.16%) was found when comparing the different cages and sampling depths. Furthermore, the composition of collected sludge was similar at all sampling points. The overall nutritional value was lower compared to sludge from land-based aquaculture; regardless, sludge from sea-based salmon production can in theory be considered a potential feed resource to be used for the production of polychaetes H. diversicolor.

Sustainable business model innovation, dynamic capabilities, and organizational design: Insights from Norwegian aquaculture

AbstractFirms must increasingly grapple with complex sustainability challenges. Business model innovation is needed to achieve radical sustainability improvements. Recent research highlights the interrelatedness between business model innovation, dynamic capabilities, and organizational design, calling for empirical work to better illuminate these relationships. These connections are relevant in sustainability contexts, where organizational barriers and drivers have been shown to either facilitate or hinder the development of dynamic capabilities for sustainable business model innovation (SBMI). This paper presents a case study of an emergent low‐carbon offshore aquaculture value chain in Norway to illuminate the importance and roles of these organizational factors. Based on our analysis, we identify those barriers and drivers present in the Norwegian salmon aquaculture industry; add to the body of theory around organizational design, dynamic capabilities, and SBMI; and offer insights for practitioners in the aquaculture sector aiming to develop dynamic capabilities for SBMI.

Salmon farming alters the structure and functioning of Norwegian maerl bed communities

Abstract Effluents resulting from fish farming activities can alter the structure and functioning of benthic ecosystems. In Norway, recent technological advances within the salmon industry have facilitated the expansion of aquaculture into shallower locations, leading to additional pressures upon coastal habitats. Maerl/rhodolith beds are important bioengineers in coastal waters—supporting highly diverse associated macrofaunal communities—and are likely to be particularly at risk. This study aims to investigate the environmental changes induced by fish farms in their vicinity and their impact on the structure and functioning of maerl bed macrofaunal communities. High dissolved nutrients and organic enrichment levels were observed close to the cages, associated with lower live maerl cover. Overall, the most substantial impact of salmon farms on macrofaunal communities was observed within 100 m from the cages. Nevertheless, changes in the structure and functioning of assemblages were evidenced up to 300 m. In the vicinity of the cages, communities were characterized by the dominance of endobenthic subsurface deposit feeders and opportunistic species, notably the polychaetes Chaetozone sp., Capitella sp. and Scoloplos armiger. Conversely, sites situated farther away from the cages exhibited higher abundances of epibenthic taxa, including crawlers, grazers and species sensitive to organic enrichment. Sites unaffected by the presence of fish farms were described by high abundances of the ophiuroid Ophiura robusta, the polychaete Proclea graffi and ostracods, reflecting more favourable environmental conditions. Such changes in macrofaunal communities highlight the vulnerability of maerl beds to the impacts of aquaculture, thus emphasizing the importance of rigorous site selection when establishing new fish farming facilities.