Lake Fisheries Research Articles

Registration and application of sea lamprey pheromones for sea lamprey control in the United States and Canada

Since the identification of 3-trifluoromethyl-4-nitrophenol as a lampricide in the 1950s, control of sea lamprey populations in the Great Lakes has largely relied on lampricides, barriers, and traps. Lampricide treatments target larval lampreys in tributaries of the Great Lakes. The Great Lakes Fishery Commission oversees sea lamprey control efforts and has invested in technologies that may target other life stages to provide a more integrated approach to sea lamprey control. One technology under development is the use of pheromones to alter behavior of spawning adults. Pheromones are considered biopesticides, which are substances made from naturally occurring products, or derived from living organisms, or a microorganism, that controls pests. We provide a review of sea lamprey management that led to the development of pheromone registration. We also describe the process used to register the first vertebrate pheromone, 3-ketopetromyzonal-24-sulfate (3kPZS) in the United States and Canada and its potential uses in sea lamprey control as a supplemental tool to chemical lampricides.

Where you trap matters: Implications for integrated sea lamprey management

Barriers and pesticides have been used in streams to control sea lamprey in the Laurentian Great Lakes for nearly 70 years. Considerable effort has been spent to develop additional control measures, but much less effort has gone toward identifying how or where additional control measures might be cost-effectively integrated into the sea lamprey control program. We use a management strategy evaluation model in Lake Michigan to identify the stream types that would be most suitable for deploying traps to remove adults prior to spawning and estimate the likely impact on adult sea lamprey abundance in subsequent years under several trapping scenarios relative to status quo abundance. The greatest reduction in lake-wide adult sea lamprey abundance predicted by the model resulted when removing adult sea lampreys from streams that are difficult for control program personnel to treat with lampricide because lampricide applications would be required less frequently. Additionally, targeting streams which experience regular sea lamprey recruitment and streams with low adult sea lamprey density should result in reduced lake-wide abundance if trapping costs are relatively low or removal is high. Our results provide direction on where to trap and why, and indicate that trapping may be a valuable part of an integrated sea lamprey control approach advancing the goals of the Great Lakes Fishery Commission.

Blue bioeconomy localities at the margins: Reconnecting Norwegian seaweed farming and Finnish small-scale lake fisheries with blue policies

The blue bioeconomy is gaining momentum in EU policy debate and various national government strategies as a pathway towards a more sustainable society. Linked to the circularity of economic processes, it combines the promise of (regional) economic development with a sustainable, bio-based transition focused on increased and novel utilisation of aquatic resources. Nonetheless, portrayed as a holistic approach, the political visions of blue bioeconomy reside predominantly in marine environments with little integration of freshwater perspectives or alternative development paths. Rooted in concepts of policy mobility, assembling processes and the positionalities of involved entities, this paper displays two regionally embedded blue bioeconomy developments – Norwegian coastal seaweed farming and Finnish lake fisheries – and their spatially diverse reconnections with national and international policy narratives. By framing a freshwater and a coastal marine case, and their spatial reconnections with an overarching yet diversely translated policy realm, the paper taps into the multiple ontologies of water in blue bioeconomy governance and presents initial empirical and methodological steps towards a relational understanding of its governance processes. Based on four key topical reconnections, the article points to a variety of challenging mismatches between policy narratives, local development processes and potentials. It also suggests conceptual and methodological implications of this approach for further research into “blue” resource governance.

Bio - Economic study of the potential development of fisheries in Lake Manzala

The research aimed to study the determinants of fish production in Manzala Lake, study the seasonal movements of fish species, and show that the area of the water area of Manzala Lake did not exceed 0.7% of the total water area of Egyptian fisheries, but it contributes about 16% of the total Egyptian fish production, respectively, and about 14 . 2% of the total Egyptian fish income. It turns out that the annual fish production in Manzala Lake is directly related to the numbers of boats, the numbers of fishermen and the fish prices, and inversely with the average annual yield of the fisherman. It is clear that the fish production in Manzala Lake fisheries exceeds the seasonal average for the fall semester from the seasonal average for the rest of the seasons of the year to being the breeding and spawning season for the fish as well as the autumn months are actual fishing months where the hunter stays for long periods in the lake, while the average for the spring is the lowest for the rest of the seasons. The necessity of continuous follow-up in the treatment of incoming agricultural wastewater for the lake, and the continuous cleansing of the Bogus lake opening and guarding it from the thief of fry, with continuous review of the maximum allowed number of fishing boats operating in the lake according to technical and economic bases.

Effects of climate and land-use changes on fish catches across lakes at a global scale

Globally, our knowledge on lake fisheries is still limited despite their importance to food security and livelihoods. Here we show that fish catches can respond either positively or negatively to climate and land-use changes, by analyzing time-series data (1970–2014) for 31 lakes across five continents. We find that effects of a climate or land-use driver (e.g., air temperature) on lake environment could be relatively consistent in directions, but consequential changes in a lake-environmental factor (e.g., water temperature) could result in either increases or decreases in fish catch in a given lake. A subsequent correlation analysis indicates that reductions in fish catch was less likely to occur in response to potential climate and land-use changes if a lake is located in a region with greater access to clean water. This finding suggests that adequate investments for water-quality protection and water-use efficiency can provide additional benefits to lake fisheries and food security.

Crossing boundaries between science and policy: Two case studies illustrate the importance of boundary organizations in the Great Lakes Basin

Boundary organizations are institutions that interface between science and policy by facilitating interactions between scientists, policy specialists, and other stakeholders to inform collaborative decision-making. Natural resource management in the Great Lakes Basin is complex and a shared exercise among two federal governments, eight states, two provinces, and over 200 sovereign Tribes, First Nations, and Métis. Many governmental agencies have recognized a need to effectively engage with other jurisdictions in order to bridge the gaps between scientific knowledge and policy decisions. As a result, boundary organizations have emerged to facilitate planning and implementation of collaborative governance frameworks. This commentary highlights how decades of shared governance of the world’s largest freshwater surface water system is augmented and assisted by boundary organizations in addressing two key Great Lakes management issues – Western Lake Erie Basin nutrient levels and Lake Michigan fisheries – which are complex, broad in scale, and pose challenges that must be addressed collaboratively across jurisdictions. While there are many governmental and non-governmental entities that engage in boundary organization-like behaviors, this commentary will be centered on three key institutions: The Great Lakes Executive Committee’s Annex 4 (Nutrients) Subcommittee, the Great Lakes Commission, and the Great Lakes Fishery Commission. We illustrate how each organization procedurally engages stakeholders, especially within state and provincial jurisdictions, to produce information and products that add breadth and capacity to manage the ecosystems of the Great Lakes. We also highlight areas of success and opportunities for improvement in collaborative governance frameworks now and into the future.

Decline of zooplankton food resources of Limnothrissa miodon fishery in Lake Kariba: Global warming‐induced ecosystem disruption by Cylindrospermopsis raciborskii

AbstractThe present study was conducted on the Lake Kariba portion of the Middle Zambezi Biosphere Reserve. Magadza (2011) previously reported the pelagic Lake Tanganyika sardine (Limnothrissa miodon) fishery introduced into Lake Kariba was declining. This phenomenon was attributed to observed climate‐change‐related warming of the lake, facilitating establishment of the invasive Cylindrospermopsis raciborskii, currently the dominant alga in the lake. Chlorophyceae contribute to less than 10% of the phytoplankton biomass. Accordingly, it was postulated that its dominance in the lake resulted in a food chain disruption because this cyanobacterium was not preferred by zooplankton grazers. Accordingly, the present study examined the feeding behaviour of L miodon with reference to available food items in the Sanyati Basin of Lake Kariba. The results highlighted a virtual absence of entomostraca zooplankton in the Sanyati Basin of Lake Kariba, in contrast to previous findings of previous studies, the avoidance of C. raciborskii in the diet of L. miodon, as measured by the Ivlev electivity index, a low stomach fullness index, the movement of L. miodon to macroinvertebrates associated with the littoral zone as a food source, and unfavourable dietary indicators of L. miodon. These results collectively suggest a food deficit for L. miodon in Lake Kariba, leading to the previously observed decline in the lake fishery.

Small-scale fishing: Income, vulnerability and livelihood strategies at Lake Itezhi-Tezhi, Zambia

ABSTRACT There is still a need for appropriate livelihood strategies to improve livelihoods of small-scale fishers, despite several roles the African inland fisheries play to fishers’ wellbeing. This study assessed the nexus between small-scale fishing and fishers’ livelihoods at Lake Itezhi-Tezhi, Zambia. Using the mixed-methods approach under a sustainable livelihood framework, findings revealed the fishing income was insufficient to improve their livelihood assets due to the low fish catches per fisher. Deficiency in fishing income was compounded by fishers’ vulnerability to shocks caused mainly by the effects of the closed fishing season and crop/livestock production failures. As such, the study suggests, among other strategies, the support of fishery stakeholders towards alternative income sources and development of a livelihood-inclusive fisheries policy framework to help enhance the livelihoods of fishers at Lake Itezhi-Tezhi fishery. Beyond this lake fishery, this study contributes similar strategies as lessons for addressing the fishers’ livelihood challenges and promoting sustainable fishing.

The effects of aquatic invasive species on recreational fishing participation and value in the Great Lakes: Possible future scenarios

The impacts of aquatic invasive species (AIS) on the recreational fishery in the Laurentian Great Lakes are of concern to managers and policy makers. Some AIS have the potential to depress sportfish populations, reducing recreational fishing opportunities and damaging local economies. Alternatives that could reduce the threat of AIS could be costly. Assessments of how AIS could affect recreational fishing participation and the economic value derived from it would contribute to the evaluation of these alternatives. We assessed best-case and worst-case scenarios for how a range of AIS could affect recreational fishing participation and economic value. We utilized previously developed scenarios for how AIS could affect sportfish populations as input for a recreational fishing model developed by Ready et al. (2018). Their model estimated changes in fishing participation and economic value from such scenarios. Given uncertainty in how AIS could affect sportfish, projected effects of AIS on economic value varied widely, with some scenarios likely to have minimal effects and others leading to losses of over $100 million annually. None of the scenarios would lead to a large percentage decrease in recreational fishing in the eight Great Lake states, largely because anglers have numerous inland fishing opportunities. Nevertheless, lakeshore communities dependent on Great Lakes fishing could still suffer considerable economic loss. Collectively the economic valuation of the range of scenarios narrows down the possible impacts on fishing and the economy that decision makers need to consider.

Evaluating community fishery management using Fishers' perceptions in the Tonle Sap lake of Cambodia

There is an emerging consensus among academics and resource managers that successful resource management systems must be developed locally and account for a diverse range of political, economic, social, technological, legal, and environmental factors. In this research we evaluate and categorize the fishers' perspectives on the environmental, economic, social, and legal impacts of transitioning from a private property system to community fisheries in Cambodia's Tonle Sap Lake. Specifically, this paper uses interview results (N = 523) to assess the perceptions of local communities following a reform in 2012, whereby a commercial leasehold system was replaced with a community-based fishery management system. Results demonstrate that this conversion of fishery management systems is perceived as helping to improve economic, environmental, and legal conditions at the macro-level, but improvements in economic productivity at the individual level are inconclusive. This paper reveals the inherent complexity, benefits, and trade-offs involved in community-based management by exploring fishers' perceptions. One implication of this study is that the data reinforce the importance of participatory engagement in the development of resource management systems.

Checking the pulse of the major commercial fisheries of lake Victoria Kenya, for sustainable management

AbstractThe present study demonstrates the declining state of the major commercial fisheries of Lake Victoria, Kenya, a situation threatening sustainability of the lake's fishery. Data in the present study were derived from resource monitoring programmes that included hydro‐acoustics (2009–2018), trawl net fishing (2011–2018), frame surveys (2000–2016) and catch assessment surveys (2000–2015). The activities provided information on fish stocks and supported advice for fisheries management. The average fish stock densities for Tanzania, Uganda and Kenya of 8.92, 8.25 and 8.19 t/km2, respectively, were relatively similar. Diplomatic and sustainable efforts for harmony in fish harvesting among the fishers of the riparian countries are encouraged given the interdependence of the lake. The Kenyan and River Kagera regions had a higher proportion (≈ 4% each) of big‐sized Nile perch (≥50 cm total length) in 2018, signifying the critical breeding areas for Nile perch. To sustain the fishery, there is need to enforce a 36%–44% effort reduction for all the major fisheries, and enforcement of gear limits to avoid harvesting of immature fish and destruction of the lake ecosystem.

A review on the status of some major fish species in Lake Victoria and possible conservation strategies

AbstractLake Victoria, the second largest freshwater lake in the world, supports an enormous flora and fauna biomass, with a large human population around the Lake. The lake is a source of food (fish), water for domestic use and crop and livestock production, transportation and tourism, among other uses. As a result of these varied uses, human intervention within the lake and its catchment has resulted in several ecological changes in the lake in recent years, with profound effects on its fish resources. One of the most notable changes is the reduction and risk of extinction of some fish species, including the endemic tilapiine species (Oreochromis esculentus and Oreochromis variabilis), catfishes (Xenoclarias eupogon), haplochromines and cyprinids (Labeo victorianus and Barbus altinialis) in the lake. The reduced biodiversity, as well as extinctions within the lake, has been attributed to the introduction of alien fish species (e.g. Nile perch (Lates niloticus) and Nile tilapia (Oreochromis niloticus) into the lake, habitat loss and cultural eutrophication. If left unchecked, these changes will have devastating effects on the lake's resources, as well as to people living around the lake and beyond who depend on the lake fisheries for their livelihood. Thus, there is an urgent need for management measures based on sound scientific research to be implemented in order to curb the loss of ichthyodiversity within the lake, as well as to save the livelihoods of those stakeholders who are either directly or indirectly dependent on the lake.

Temporal trends in fish mercury concentrations in an Adirondack Lake managed with a continual predator removal program.

Mercury is a neurotoxic pollutant and contamination in remote ecosystems due to atmospheric mercury deposition coupled with watershed characteristics that influence mercury bioavailability. Biological interactions that affect mercury bioaccumulation are especially relevant as fish assemblages change in response to species introductions and lake management practices. We studied the influence of shifting food web dynamics on mercury in fisheries of Little Moose Lake in the southwestern Adirondack Mountains of New York, USA. Annual removal of non-native Smallmouth Bass (Micropterus dolomieu) has been used as a management strategy since 2000 to restore the native fish assemblage and food web in favor of Lake Trout (Salvelinus namaycush). Changes in total mercury, stable carbon (13C/12C) and nitrogen (15N/14N) isotopes, and growth were evaluated for Lake Trout and Smallmouth Bass. Growth rates increased for both predators and trophic position increased for Lake Trout post-removal. Mercury concentrations in Lake Trout increased over the 16-year study period influenced by a diet shift from invertebrates to higher trophic level prey fish, regardless of increased growth. Smallmouth Bass mercury concentrations decreased with compensatory growth from a reduced population size. These contrasting trends indicate that changes in mercury deposition were not the primary driver for mercury bioaccumulation responses in Little Moose Lake. Stable isotope values changed for both predators and for several lower trophic level organisms, likely reflecting changes in nutrient cycling and/or inputs. Our findings emphasize the potential role of fisheries management on whole-lake and predatory fish responses to mercury contamination in temperate lakes.

The current state of fishing and extracting the living aquatic resources in the Black Sea region of Ukraine

The development of open spaces and resources of the Black Sea is one of the main directions of the Black Sea region (the Odessa, Mykolaiv and Kherson regions). The essence of the region policy allows to cooperate with the most countries of the world community and brings an income both to the budget of the regions and to the state budget. Industrial fisheries is an extractive branch of the fishing industry that uses the natural resources of the oceans, seas, lakes, rivers, reservoirs: various species of fish, marine mammals, shellfish, crustaceans and aquatic vegetation. Fisheries can be considered as one type of nature using which consists in the extraction of fish and other sea products (fish, invertebrates, algae, etc.). The purpose of the work was to find out a current state of fishing and extracting the living aquatic resources in the Black Sea region, namely in the Odessa, Mykolaiv and Kherson regions. An assessment of a current state of extracting the aquatic bioresources in general and in the inland water bodies in the Black Sea region, namely in the Odessa, Mykolaiv and Kherson regions for the period from 2010 to 2018, was carried out on the basis of specialized literature. The state of extracting the aquatic bioresources in general and in the inland water bodies from 2010 to 2018; the amount of caught fish in this region; the state of fisheries of the studied region were investigated. Fish farming is a branch of the national economy that is engaged in farming, increasing and improving a quality of the fish stocks in the water bodies and filling the fish resources. In order to maintain and increase the stocks of valuable industrial fish in our country the extensive measures for artificial fish farming, improving the conditions of natural reproduction of fish, as well as the development of lake and pond fisheries for the commercial fish production are being taken. Much work is being done to acclimatize valuable industrial fish species and other fishing objects, aimed at expanding a fish species composition and increasing the fish stocks. It was found that according to the statistics of the State Statistics Committee of Ukraine, the analysis of the exraction of fish and aquatic biological resources in the Black Sea region (Odesa, Mykolaiv and Kherson regions) showed that an increase in the volume of fish catching and extracting the living aquatic resources occurred only due to inland waters.

Carp (Cyprinidae) Fisheries in Swedish Lakes: A Combined Environmental Assessment Approach to Evaluate Data-limited Freshwater Fish Resources as Food

The role of aquatic resources to food security is both promising and constrained since the global seafood consumption is increasing while marine fisheries approach the limit of what it can produce. In Sweden, the seafood consumption per capita is higher than the European and world average but the current dietary advice is to increase consumption. Freshwater fisheries have in general been paid less attention in food security discussions. Carp fishes (Cyprinidae) in Sweden have lost their historical value and are currently, both understudied and underutilized. Here we use a combined environmental assessment approach to examine the environmental sustainability of current and potential cyprinid fisheries. We found that current commercial fisheries for Swedish cyprinids in lakes have an average carbon footprint of 0.77 kg CO2e per kg of edible product, substantially smaller than most of the popular marine and terrestrial protein sources consumed in Sweden today. This could be even lower if cyprinid resources were better utilized than currently. The cyprinids however exhibited different vulnerability to fishing pressure and are today associated with data deficiencies. Hence, it is currently uncertain how much food for human consumption they can contribute to. Improved consumer interest and management attention is needed, but to the Swedish diet, cyprinids offer a promising opportunity for future more sustainable and nutritious food systems.

Mercury source changes and food web shifts alter contamination signatures of predatory fish from Lake Michigan

To understand the impact reduced mercury (Hg) loading and invasive species have had on methylmercury bioaccumulation in predator fish of Lake Michigan, we reconstructed bioaccumulation trends from a fish archive (1978 to 2012). By measuring fish Hg stable isotope ratios, we related temporal changes in Hg concentrations to varying Hg sources. Additionally, dietary tracers were necessary to identify food web influences. Through combined Hg, C, and N stable isotopic analyses, we were able to differentiate between a shift in Hg sources to fish and periods when energetic transitions (from dreissenid mussels) led to the assimilation of contrasting Hg pools (2000 to present). In the late 1980s, lake trout δ202Hg increased (0.4‰) from regulatory reductions in regional Hg emissions. After 2000, C and N isotopes ratios revealed altered food web pathways, resulting in a benthic energetic shift and changes to Hg bioaccumulation. Continued increases in δ202Hg indicate fish are responding to several United States mercury emission mitigation strategies that were initiated circa 1990 and continued through the 2011 promulgation of the Mercury and Air Toxics Standards rule. Unlike archives of sediments, this fish archive tracks Hg sources susceptible to bioaccumulation in Great Lakes fisheries. Analysis reveals that trends in fish Hg concentrations can be substantially affected by shifts in trophic structure and dietary preferences initiated by invasive species in the Great Lakes. This does not diminish the benefits of declining emissions over this period, as fish Hg concentrations would have been higher without these actions.

Transboundary Environmental Governance Across the World’s Longest Border. By Brooks, Stephen, and Andrea Olive, eds. 2018. Winnipeg: University of Manitoba Press.

<i>Transboundary Environmental Governance Across the World’s Longest Border</i>. By Brooks, Stephen, and Andrea Olive, eds. 2018. Winnipeg: University of Manitoba Press.

The effect of anthropogenic and environmental factors in coupled human‐natural systems: Evidence from Lake Zürich

AbstractExploiting a rich data set including both individual fishing activities and ecology, we study how eutrophication and climate warming influence plankton biodiversity in Lake Zürich and the consequent effects on fishers’ behavior and fishery yield. Our analysis indicates that changes in the fishery of Lake Zürich were driven by complex dynamic interactions between fishing efforts, environmental conditions, and lake ecosystem ecology. Results show that nutrient levels and climate warming have both direct and indirect dynamic and nonlinear effects on both fishers’ behavior and lake productivity. Ecological factors such as plankton abundance and diversity affect the dynamics of the fish population, which, in turn, influences fishing effort. The analysis highlights the importance and the interdependence of ecological‐human linkages in aquatic ecosystems.Recommendations for Resource Managers This model estimates and simulates the effects of temperature and nutrients on the ecology and the management of a commercial lake fishery. Natural and anthropogenic factors have both direct and indirect effects on fishing intensity and the dynamics of lake productivity. In the long term, increasing phosphorus has negative impacts on the plankton of the lake; higher nitrogen has a positive impact on zoo‐abundance, but a negative impact on zoo‐richness; higher temperatures have positive effects on phytoplankton. Considerable heterogeneity exists in both in lake ecology at different habitats (top vs. bottom of the lake) and behavioral response (pelagic nets vs. demersal nets) to environmental fluctuations.

Cross impact analysis and data mining variable hierarchy of stakeholder responses for sustainable development of Schizothorax fisheries in Kashmir lakes, India

AbstractThis study documented the history of lake fisheries in Kashmir, India, and estimated the trends in fish production using Kane's cross impact analysis (CIA) and stakeholders’ willingness to pay (WTP) for the restoration of the Schizothorax fisheries. Kane's CIA model for Lake Dal indicated a perceptible drop in Schizothorax production in the long run, and that the total catch is being maintained by an increasing contribution by carp. In Lake Wular, the CIA indicated that the size of the lake still offers scope for the co‐existence and growth of both Schizothorax as well as carp. A Classification and Regression Tree (CART) model was used to data mine multiple stakeholder responses to make a case for sustainable development of the Schizothorax fisheries in the lakes of Kashmir. The amount of time spent on the lakes to earn their livelihoods emerged as the single most important variable that determined WTP by stakeholders followed by income, type of stakeholder and age. The pruned tree gave the hierarchy of the variables that determined WTP. The results made a strong case for a concerted multi‐institutional action plan for the restoration of the Schizothorax fisheries in the lakes of Kashmir.

Adapting to climate change: guidance for the management of inland glacial lake fisheries

Tingley RW III, Paukert CP, Sass GG, Jacobson PC, Hansen GJA, Lynch AJ, Shannon PD. 2019. Adapting to climate change: Guidance for the management of inland glacial lake fisheries. Lake Reserv Manage. 35:435–452.Climate change is altering glacial lake fisheries in the United States, presenting a complex challenge for fisheries managers. Here we provide a regional perspective to guide management of heterogeneous and yet interdependent fishery resources in glacial lakes of the upper Midwest. Our main objective was to promote the adaptation of inland glacial lakes fisheries management to climate change by outlining processes that support regional plans. Using examples from the glacial lakes region, we outline an approach for regional prioritization, specify strategies for moving from regional prioritization to on-the-ground action, and provide guidance on the implementation of management plans given resource limitations and potential stakeholder conflict. We find that integrating ecological, social, and economic data with climate change vulnerability assessments can be useful in generating “lake-priority levels” to help identify where to focus actions to support system resilience. Managers can use lake-priority levels and ecosystem-specific strategies to make decisions about where and when to apply fisheries management action ranging from traditional (i.e., stocking, harvest regulations) to nontraditional approaches (i.e., catchment land management). Although the implementation of several approaches may be beyond an agency’s financial and logistical capacity, funds can be secured through other sources ranging from grant programs to nontraditional partnerships identified by “thinking outside the lake.” Regional plans may be an important step toward successful climate adaptation for inland glacial lakes fisheries management, and the proactive efforts of managers may help facilitate their development and implementation.