Atlantic Salmon Fishery Research Articles

Re-establishment of an extinct breeding colony of Brünnich’s Guillemot Uria lomvia in West Greenland

The breeding population of Brünnich’s Guillemot Uria lomvia in South and West Greenland has been decreasing for decades and some colonies have even disappeared (Merkel et al. 2014). Among these was one of the largest colonies, Salleq in Uummannaq Fjord (70°96’N 52°25’W; Figure 1), which was estimated at half a million birds in c. 1920 (Bertelsen 1921) and 150,000 birds in 1949 (Salomonsen 1950). These figures are most likely overestimations (Falk & Kampp 1997), but there is no doubt that the colony was among the largest in West Greenland. The colony then drastically decreased in size until 1975, when only 4,500 birds were counted (Falk & Kampp 1997). In 1984, there were only 150 individuals present and all were observed on the water below the cliff. In 1987, 50 birds were observed on the cliff without evidence of breeding, and the site was completely deserted by 1990 (Evans & Kampp 1991). The same fate was recorded for Black-legged Kittiwakes Rissa tridactyla (hereafter ‘Kittiwakes’) and Razorbills Alca torda. The former declined from around 10,000 pairs in 1949, to 800 nests in 1975 and to zero in 1994 (F. Salomonsen unpublished; Boertmann et al. 1996). Razorbills declined from a few pairs in 1949 and 1975 to zero in 1994 (Boertmann et al. 1996). However, no population changes have been recorded for the Northern Fulmars Fulmarus glacialis which breed in huge numbers on the cliff. The decline and extinction of the Salleq Brünnich’s Guillemot colony in the decades after the Second World War was primarily caused by excessive hunting during spring. Fleischer (1994), the former editor of a Greenlandic newspaper, described how in the 1930s it was common in spring, when sea ice still covered the waters, to camp below the Salleq cliff and hunt hundreds of Brünnich’s Guillemots in a day. This occurred every spring, and people would travel from afar to participate in this hunt. This high hunting pressure was reflected in a higher recovery rate of ringed birds from Salleq in comparison to colonies in other parts of West Greenland (Kampp 1991). Naturally, the colony could not sustain such hunting pressure across multiple decades, and eventually disappeared. Another factor impacting the Brünnich’s Guillemot populations in West Greenland was bycatch by an extensive offshore drift net fishery for Atlantic Salmon Salmo salar, which peaked around 1970 and stopped in 1976 (Falk & Durinck 1991).

Attitudes and behaviors for understanding compliance in Greenland's Atlantic salmon (Salmo salar) fishery

AbstractNoncompliance is a central challenge for conservation, but in settings with limited access to behavioral data, it can be difficult to evaluate what drives compliance. Conservationists can measure and evaluate resource users' attitudes, and in so doing, leverage a complementary, nonbehavioral measure for evaluating compliance. In Greenland, wild Atlantic salmon (Salmo salar) fishers are under increasing regulatory pressure to report salmon catch because the majority of North Atlantic salmon stocks are classified as suffering. The objective of this study is to measure salmon catch reporting compliance, reporting behavior, and attitudes toward Greenland's salmon management. We surveyed Greenland's licensed salmon fishers, used an unmatched count technique to estimate the incidence of underreporting salmon catch, and linked salmon fishers' actual catch reports to their survey responses. In 2019, more than 84% of salmon fishers reported their catch and demonstrating high levels of compliance. We also found that salmon fishers did not indicate strong instrumental motivations for reporting, but exhibited moral obligations and normative, legitimacy‐based motivations to report catch. Salmon fishers found regulations to be fair, and that regulatory authorities were professional and acted honestly. Catch underreporting was also remarkably low, with 90–94% of respondents stating that they report all their catch. Joining together individuals' attitudinal and behavioral responses to conservation rules illustrates the benefits and limitations of expanding actor‐based theories of compliance. This case of already high levels of compliance offers empirical evidence for further improving fisheries compliance, and it also illustrates the limitations that fishery managers face when conserving a highly migratory species.

On inter-organizational trust, control and risk in transboundary fisheries governance

Inter-organizational collaboration is often considered essential to transboundary fishery governance, due, in part, to the high levels of task interdependence, the remote and often treacherous conditions, and the limited levels of information available to any policy actor on resource status. In the high seas, Regional Fisheries Management Organizations (RFMOs) are responsible for sustainably managing highly migratory and straddling fish stocks through the implementation of ecosystem-based approaches and ensuring adequate inter-jurisdictional cooperation. A central question facing RFMO governance is therefore how to structure and sustain inter-organizational transboundary collaboration under high uncertainty? This paper presents the case of the North Atlantic Salmon Conservation Organization (NASCO), conceptualized as a strategic alliance between the bureaucratic organizations responsible for north Atlantic salmon fishery management in the member countries. We identify and explain how dimensions of trust, control, and perceived risk have structured the collaborative performance of the alliance. The application of an integrated trust-control-risk framework increases conceptual clarity for how, when and why alliance managers might seek to develop different forms of trust through different management control systems in ways that further multi-actor collaborative network performance. Future research needs are identified, including better understanding how managerial strategies and control mechanisms facilitate inter-organizational trust in transboundary governance settings and mitigate the perceived risks of working together.

Deterrents and nudges improve compliance in Greenland's Atlantic salmon (Salmo salar) fishery

Abstract Fishers reporting all of their catch is key to estimating population viabilities of vulnerable, highly migratory fish stocks. However, fishery managers find it difficult to ensure that this reporting behavior takes place consistently. Wild Atlantic salmon (Salmo salar) are a highly migratory and internationally contested species with a threatened conservation status. Greenland manages a fishery for Atlantic salmon, and its coastline serves as a key feeding ground in the life history of Atlantic salmon. However, salmon catch is underreported by fishers, even though they are required to report. Deterring noncompliant behavior with penalties and sending short message service (SMS) messages have been shown to increase compliance, but no known studies test their effect on compliance with catch reporting requirements. We evaluated two interventions for their effect on salmon catch reporting behavior among Greenland's salmon fishers. Salmon fishers were 41% more likely to report (p < 0.00) once a deterrence-based intervention was implemented. Fishers who received SMS reminders were 6% more likely to report salmon catch (p < 0.1). These results highlight the complementarity of nudges and command-and-control interventions to increase compliance with catch reporting requirements.

Mortality of Atlantic salmon after catch and release angling: assessment of a recreational Atlantic salmon fishery in a changing climate

Human activities have the potential to accelerate population-level decline by contributing to climate warming and decreasing the capacity of species to survive warming temperatures. Here we build a predictive model to test interactions between river warming and catch and release mortality in recreational fisheries for Atlantic salmon (Salmo salar) by compiling and analyzing published data. We then test whether warming has occurred in rivers where angling occurs and whether angling opportunities have been restricted through increased river closures due to high water temperatures. We find that catch and release mortalities are low (<0.05) at cool river temperatures (<12 °C). At river temperatures often leading to fishery closures (between 18 and 20 °C), mortalities range from 0.07 to 0.33 (mean = 0.16). River temperatures on the east and southeast coasts of Newfoundland have warmed, leading to an increase in fishery closures in recent years. By contrast, river temperatures in southern Labrador have warmed slightly, with only one documented river closure. Accordingly, increasing temperatures will increase the frequency of river closures and likely result in higher mortality in caught and released Atlantic salmon in rivers that remain open to catch and release angling at warm water temperatures.

Potential for offshore aquaculture development in North Korea: Focusing on Atlantic salmon farming

This study investigated the potential for Atlantic salmon farming in North Korea. Farmed Atlantic salmon (Salmo salar) are aquaculture products commonly consumed in East Asia, but they are not commercially produced in large quantities. One barrier to Atlantic salmon farming is that the marine environmental conditions (i.e., water temperatures) in much of East Asia are unsuitable. North Korea has recently initiated Atlantic salmon farming assuming it has appropriate locations for it. If North Korea indeed has suitable locations for successful Atlantic salmon aquaculture and the United Nations' sanctions were lifted, the country's Atlantic salmon farming project might have potential for successful inter-Korean economic collaborations. The current study analyzed North Korea's possible farming sites using remote sensing data, and it used those findings to evaluate the feasibility of inter-Korean Atlantic salmon fishery collaborations and to propose policy implications. Remote sensing information estimated sea surface temperatures and hydrodynamic modeling extended that to estimate the sea temperatures at various depths to precisely propose appropriate farming locations in North Korea. The results indicated that most of North Korea's sea surface temperatures were below 20 °C in January through June. However, the surface temperatures in July and August exceeded 20 °C, indicating unsuitability for Atlantic salmon farming during that period. The water temperatures at the 25-m depth were below 20 °C year round, and Atlantic salmon farming would be possible there using submersible farming technologies, such as plant-type offshore fish farming systems.

Evidence for freshwater residency among Lake Ontario Atlantic salmon (Salmo salar) spawning in New York

Prior to their extirpation around 1900 CE, Lake Ontario hosted the world’s largest freshwater Atlantic salmon (Salmo salar) fishery. Due to their early disappearance, questions remained about fundamental aspects of the species’ biology, such as whether they belonged to sea-run (anadromous) or freshwater resident (potamodromous) ecotypes. Recent isotopic analyses have demonstrated that the complex of Atlantic salmon populations spawning in tributaries emptying along Lake Ontario’s northern shores were potamodromous. However, no evidence has yet been gathered for Atlantic salmon migratory behaviour from Lake Ontario’s southeastern region, where historical observations suggest both anadromous and potamodromous populations may have spawned. Here, we provide the first results for isotopic analyses of bone collagen from seven fish bones from archaeological sites (c. 1427 to 1600 CE) identified as Atlantic salmon through ancient DNA and zooarchaeological analyses. The results of the isotopic analyses confirm that at least some of the salmon spawning in tributaries emptying into Lake Ontario’s southeastern shores were also potamodromous. Although further analyses are needed, this suggests anadromy may have been completely absent in Lake Ontario’s complex of Atlantic salmon populations in recent centuries.

Range-wide regional assignment of Atlantic salmon (Salmo salar) using genome wide single-nucleotide polymorphisms

The estimation of stock specific exploitation is imperative to fisheries management and the conservation of biodiversity, particularly in instances where fisheries simultaneously exploit mixtures of stocks. Mixed stock harvests are particularly common in species that have extensive marine migrations, such as Atlantic and Pacific salmon. Here we develop a range-wide genetic baseline for Atlantic salmon (Salmo salar) from North American and European rivers to allow regional assignment of individuals targeted in international mixed stock fisheries. A combination of published data and additional genotyping was used to assemble a dataset of 96 SNPs for 285 range-wide Atlantic salmon populations for regional assignment. Clustering of baseline samples identified 20 North American and eight European reporting groups with mean individual assignment accuracy of 90% (range 70–100%). This baseline was applied to disentangle the stock composition of individuals in a subset of individuals from the West Greenland Atlantic salmon fishery. Genetic mixture analysis revealed that both European and North American individuals originated from multiple regions, with 92% of European individuals originating from the United Kingdom and Ireland, and North American individuals originating from three regions; Gulf of St. Lawrence (28%), Gaspé Peninsula (23%), and coastal Labrador (21%). The baseline represents a significant resource for the management of Atlantic salmon fisheries and the quantification of salmon migration patterns at sea.

Hatching Knowledge: A Case Study on the Hybridization of Local Ecological Knowledge and Scientific Knowledge in Small-Scale Atlantic Salmon (Salmo salar) Cultivation in Norway

We investigate drivers of hybridization of local ecological knowledge (LEK) and scientific knowledge (SK) in small-scale Atlantic salmon (Salmo salar) fisheries in western Norway through a case study from the Orsta River. We find three primary drivers of knowledge hybridization in local fishing groups as part of wild Atlantic salmon cultivation activities: facilitating intergenerational knowledge exchange, coping with regulatory change, and improving the perceived validity of local knowledge sets. We also identify three challenges to knowledge hybridization, and discuss how both drivers and challenges relate to once complementary SK and LEK sets that have diverged as SK has become more technical and complex. We examine the processes by which LEK and SK develop, evolve, and are used to facilitate wild salmon conservation in these fisheries and discuss the role hatcheries can play adapting and utilizing large-scale SK and salmon policy to the local environment through hybridization processes. We conclude with recommendations as to how reframing managerial views on hatcheries as facilitators of knowledge production and transfer may improve both the accessibility of SK to local communities and the integration of LEK into Norwegian wild salmon management.

A travel cost evaluation of the benefits of two destination salmon rivers in Ireland

Fishing for Atlantic salmon (Salmo salar) is a popular recreational activity in several northern hemisphere countries. This paper extends the empirical literature using the travel cost method to estimate the demand function for two of Ireland's premier salmon fisheries: the rivers Moy and Corrib. Data were collected by an on-site questionnaire and demand was estimated using count data models. Several findings have relevance to other premier destination Atlantic salmon fisheries. While international visiting anglers are often prized over domestic anglers, this research indicates no difference between domestic and overseas anglers in terms of their angling demand. Second, an estimated price elasticity of demand of −1.04 indicates that anglers at these premier fisheries are quite cost sensitive, which is counter to previous estimates. Whether this result is more generally applicable at other premier salmon angling sites requires further research but it highlights the difficult balance fishery managers face when increasing permit prices. Finally, beyond the impact of higher travel costs on demand, domestic but not overseas anglers’ demand declines as distance to the fishing sites increases. Management implicationsResults from this study are useful to improve fishery management in many salmon destinations. Managers may use results to tailor marketing actions across markets and assess the expected changes of fishing activities when manipulating the variables affecting the demand. In particular, most important findings include:•The daily spending of tourists is high and assures a source of income to local communities;•A large consumer surplus, suggesting that salmon fishing experience is valuable;•Local and international anglers are not statistically different, which suggests that these markets are equally attractive;•An elastic demand that implies that larger prices might reduce the number of trips made by anglers; in this regard a policy acting on price to increase revenues should be evaluated carefully.

Effect of discharge and habitat type on the occurrence and severity of Didymosphenia geminata mats in the Restigouche River, eastern Canada

AbstractSince 2006, the Restigouche River watershed, eastern Canada, has been affected by nuisance growths of the mat‐forming diatom, Didymosphenia geminata. In 2010, in view of the potential impacts of this alga on the local Atlantic salmon fishery, we created a volunteer monitoring network to assess D. geminata mat severity within the watershed. Over the course of 6 monitoring summers, more than 1,200 observations of D. geminata mat severity were reported in 20 subwatersheds of the Restigouche River basin. Observations were mapped to illustrate the yearly severity of D. geminata mats throughout the watershed. Metrics were then extracted from this dataset to assess the spatial and temporal variability of mat severity. At the reach scale, D. geminata occurrence was predominantly found in riffles compared to any other river habitat type. At the watershed scale, a two‐sample Kolmogorov–Smirnov test highlighted a significant effect of maximum spring discharge on mean annual D. geminata mat severity, indicating that when maximum spring discharge is high, severity of D. geminata mats in the following months is significantly lower. Additionally, maximum spring discharge explained 71% of the variability in annual mat severity. This study contributes to the understanding of mat severity dynamics and illustrates the value of volunteer monitoring networks for studying complex ecosystem dynamics.

Genotyping-by-sequencing of genome-wide microsatellite loci reveals fine-scale harvest composition in a coastal Atlantic salmon fishery.

Individual assignment and genetic mixture analysis are commonly utilized in contemporary wildlife and fisheries management. Although microsatellite loci provide unparalleled numbers of alleles per locus, their use in assignment applications is increasingly limited. However, next‐generation sequencing, in conjunction with novel bioinformatic tools, allows large numbers of microsatellite loci to be simultaneously genotyped, presenting new opportunities for individual assignment and genetic mixture analysis. Here, we scanned the published Atlantic salmon genome to identify 706 microsatellite loci, from which we developed a final panel of 101 microsatellites distributed across the genome (average 3.4 loci per chromosome). Using samples from 35 Atlantic salmon populations (n = 1,485 individuals) from coastal Labrador, Canada, a region characterized by low levels of differentiation in this species, this panel identified 844 alleles (average of 8.4 alleles per locus). Simulation‐based evaluations of assignment and mixture identification accuracy revealed unprecedented resolution, clearly identifying 26 rivers or groups of rivers spanning 500 km of coastline. This baseline was used to examine the stock composition of 696 individuals harvested in the Labrador Atlantic salmon fishery and revealed that coastal fisheries largely targeted regional groups (<300 km). This work suggests that the development and application of large sequenced microsatellite panels presents great potential for stock resolution in Atlantic salmon and more broadly in other exploited anadromous and marine species.

Response of Anglers to Less‐Restrictive Harvest Controls in a Recreational Atlantic Salmon Fishery

AbstractIn any fishery, it is important to know whether management decisions have an impact on catch and effort. This study demonstrates that bag limits can be an effective management tool for reducing effort when dealing with a retention‐oriented angling population. Since 1997, four different management regimes (MRs) have been applied to a recreational Atlantic Salmon Salmo salar fishery on Harry's River in Newfoundland, Canada. The four MRs include catch and release only (MR1); catch and release at the start of the season, with allowed retention after an in‐season review of stock status (MR2); retention angling for the whole season, with a fixed bag limit of two salmon (MR3); and retention angling for the whole season, with an increase in bag limit from two to four salmon after an in‐season review (MR4). A time series MA(1) model (moving average of order 1) was used to study the effect of MR on effort, with salmon abundance (measured as adult returns to the river) included as a confounding variable. Significantly less effort was reported by anglers fishing Harry's River under an MR1 fishery compared with any other management scenario. However, MR1 produced the greatest average CPUE, suggesting that a catch‐and‐release fishery attracted a more skilled or differently motivated angler. Catch and effort were linearly correlated, with an expected increase in total catch of 0.6 Atlantic Salmon for every extra day of effort. The greatest difference in effort occurred between MR1 and MR3, suggesting that a compromise between catch and release only and a bag limit of four salmon would likely satisfy challenge‐seeking as well as harvest‐oriented anglers.

Genetic stock identification of Atlantic salmon caught in the Faroese fishery

At present there is no fishery for Atlantic salmon (Salmo salar L.) in the Faroes Exclusive Economic Zone. However, where national or stock-complex management units can achieve their Conservation Limits, there is potential for there to be a managed exploitable surplus in the area. In order to inform management decisions a study was undertaken to extract DNA from historical scale samples caught in the Faroes long-line fishery and, using microsatellites, to perform genetic assignments to estimate the historical stock composition of the catch. Two genetic reference baselines were used. An Atlantic-wide cross-range baseline using six microsatellite loci was established using 1930 fish from 12 regions on the western Atlantic and the same number of fish from 34 sites on the eastern Atlantic. An eastern Atlantic baseline was developed using 14 microsatellites and the same 1930 fish from the 34 eastern Atlantic sites. Mixed stock fishery analysis was based on 656 scale samples collected during two fishing seasons, 1993/4 and 1994/5 and assigned to a both the cross-range and European reference baselines. This study provides the first direct measure of the proportion of North American salmon in catches within the Faroes EEZ, with overall 16% of the total samples being identified as of North American origin and 84% as European. Of the European fish, 62% were identified as coming from the Northern Europe (Russia, Finland, Norway and Sweden), 37% from Southern European (UK, Ireland, France and Spain) and 1% from Iceland. The study also found significant variation in stock proportions across years and through seasons. This study has provided useful estimates of historical fishery composition in the absence of contemporary samples.

Genetic mixed-stock analysis disentangles spatial and temporal variation in composition of the West Greenland Atlantic Salmon fishery

Abstract The West Greenland Atlantic Salmon (Salmo salar) fishery represents the largest remaining mixed-stock fishery for Atlantic Salmon in the Northwest Atlantic and targets multi-sea-winter (MSW) salmon from throughout North America and Europe. We evaluated stock composition of salmon harvested in the waters off West Greenland (n = 5684 individuals) using genetic mixture analysis and individual assignment to inform conservation of North American populations, many of which are failing to meet management targets. Regional contributions to this fishery were estimated using 2169 individuals sampled throughout the fishery between 2011 and 2014. Of these, 22% were identified as European in origin. Major North American contributions were detected from Labrador (∼20%), the Southern Gulf/Cape Breton (29%), and the Gaspe Peninsula (29%). Minor contributions (∼5%) were detected from Newfoundland, Ungava, and Quebec regions. Region-specific catches were extrapolated using estimates of composition and fishery catch logs and harvests ranged from 300 to 600 and 2000 to 3000 individuals for minor and major constituents, respectively. To evaluate the temporal stability of the observed fishery composition, we extended the temporal coverage through the inclusion of previously published data (1995–2006, n = 3095) and data from archived scales (1968–1998, n = 420). Examination of the complete time-series (47 years) suggests relative stability in stock proportions since the late 1980s. Genetic estimates of stock composition were significantly associated with model-based estimates of returning MSW salmon (individual years r = 0.69, and overall mean r = 0.96). This work demonstrates that the analysis of both contemporary and archived samples in a mixed-stock context can disentangle levels of regional exploitation and directly inform assessment and conservation of Atlantic Salmon in the West Greenland interceptory Atlantic Salmon fishery.

Use of simulation approaches to evaluate the consequences of catch-and-release angling on the migration behaviour of adult Atlantic salmon (Salmo salar)

Given most Atlantic salmon (Salmo salar) released by anglers survive (proportion=0.97 in this study), economically and culturally important recreational Atlantic salmon fisheries are increasingly incorporating catch-and-release. Sublethal alterations to behaviour with potential individual fitness costs are a possible consequence of catch-and-release but are difficult to measure empirically relative to uncaptured fish. To test for sublethal effects of angling on migratory movements, 39 salmon were captured by recreational anglers, externally tagged with radio transmitters, and released. Data from the annual visual drift count of spawning salmon were used to calculate the probability of spawning in each pool of the river and input into simulation models. Simulation models were used to test the hypothesis that catch-and-release did not affect the upriver movement of 30 salmon tracked to spawning grounds. Ten thousand simulation steps selected a spawning pool for each of the tagged salmon, permitting a calculation of the average expected movement by salmon for comparison to the average movement observed with telemetry. The average observed movement by the released salmon was significantly less than the average expected movement generated by all three null models, indicating a sublethal effect of catch-and-release on the migration of Atlantic salmon.

Genetic mixed stock analysis of an interceptory Atlantic salmon fishery in the Northwest Atlantic

Interceptory fisheries represent an ongoing threat to migratory fish stocks particularly when managed in the absence of stock specific catch and exploitation information. Atlantic salmon from the southern portion of the North American range may be subject to exploitation in the commercial and recreational salmon fisheries occurring in the French territorial waters surrounding St. Pierre and Miquelon off southern Newfoundland. We evaluated stock composition of Atlantic salmon harvested in the St. Pierre and Miquelon Atlantic salmon fishery using genetic mixture analysis and individual assignment with a microsatellite baseline (15 loci, 12,409 individuals, 12 regional groups) encompassing the species western Atlantic range. Individual salmon were sampled from the St. Pierre and Miquelon fishery over four years (2004, 2011, 2013, and 2014). Biological characteristics indicate significant variation among years in the size and age distribution. Nonetheless, estimates of stock composition of the samples showed consistent dominance of three regions (i.e., Southern Gulf of St. Lawrence, Gaspe Peninsula, and Newfoundland). Together salmon from these regions accounted for more than 70% of annual harvest over the decade examined. Comparison of individual assignments and biological characteristics revealed a trend of declining fresh water age with latitude of assigned region. Moreover, locally harvested Newfoundland salmon were ten times more likely to be small or one sea winter individuals whereas Quebec and Gaspe Peninsula salmon were two-three times more likely to be harvested as large or two sea winter salmon. Estimates of region specific catch were highest for salmon from the southern Gulf of St. Lawrence region ranging from 242 to 887 individuals annually. This work illustrates how genetic analysis of interceptory marine fisheries can directly inform assessment and management efforts in highly migratory marine species.

Genetic evidence of local exploitation of Atlantic salmon in a coastal subsistence fishery in the Northwest Atlantic

Fisheries targeting mixtures of populations risk the overutilization of minor stock constituents unless harvests are monitored and managed. We evaluated stock composition and exploitation of Atlantic salmon (Salmo salar) in a subsistence fishery in coastal Labrador, Canada, using genetic mixture analysis and individual assignment with a microsatellite baseline (15 loci, 11 829 individuals, 12 regional groups) encompassing the species’ western Atlantic range. Bayesian and maximum likelihood mixture analyses of fishery samples over 6 years (2006–2011; 1772 individuals) indicate contributions of adjacent stocks of 96%–97%. Estimates of fishery-associated exploitation were highest for Labrador salmon (4.2%–10.6% per year) and generally &lt;1% for other regions. Individual assignment of fishery samples indicated nonlocal contributions to the fishery (e.g., Quebec, Newfoundland) were rare and primarily in southern Labrador, consistent with migration pathways utilizing the Strait of Belle Isle. This work illustrates how genetic analysis of mixed stock Atlantic salmon fisheries in the Northwest Atlantic using this new baseline can disentangle exploitation and reveal complex migratory behaviours.

NOTE: First record of natural reproduction by Atlantic salmon (Salmo salar) in the St. Marys River, Michigan

Atlantic salmon (Salmo salar) are native to Lake Ontario; but their populations severely declined by the late 1800s due to human influences. During the early to mid-1900s, Atlantic salmon were stocked throughout the Great Lakes in effort to reestablish them into Lake Ontario and introduce the species into the upper Great Lakes. However, these efforts experienced minimal success. In 1987, Lake Superior State University and the Michigan Department of Natural Resources began stocking Atlantic salmon in the St. Marys River, Michigan, which has resulted in a successful, self-supporting hatchery operation and stable recreational Atlantic salmon fishery. Possibly due to a combination of competition with other salmonid species for spawning habitat, prey selection causing detrimental effects on early life stages and high rates of early mortality syndrome, Atlantic salmon appeared to be severely limited in their ability to naturally reproduce within the upper Great Lakes. In 2012, the first unequivocal documentation of naturally reproduced Atlantic salmon in the St. Marys River was recorded, downstream from the compensation works and parallel to the Soo Locks in Sault Ste. Marie, Michigan.

THE ECONOMICS OF CONFLICTING INTERESTS: NORTHERN BALTIC SALMON FISHERY ADAPTION TO GRAY SEAL ABUNDANCE

AbstractThe successful conservation of gray seals has led to increased seal‐induced damage to the Atlantic salmon fisheries of the Baltic Sea. This paper addresses the conflict between the conservation of a formerly endangered species, the gray seal, and professional fishermen, whose livelihoods are affected by both seal‐induced damage and salmon fisheries management. We develop a bioeconomic model that incorporates the age structure of Atlantic salmon and gray seal populations. To determine the social optimum, we maximize the discounted net present value of the trap net fishery, taking into account the presence of seals in the form of seal‐induced losses, which we describe using a damage function. By choosing the optimal combination of fishing gear over time, we obtain the socially optimal fishing efforts, salmon stock size, and salmon catch. In addition, we study the private effects of introducing a technology subsidy aimed at mitigating the seal‐salmon conflict. The results suggest that technological adaptation would effectively reduce the cause of the conflict, while a technology subsidy encouraging such adaptation would shift the economic responsibility from individual fishermen to the broader public.