From Catastrophe to Recovery: Stories of Fishery Management Success

<i>Abstract.</i>—Since the mid-1800s, human activities have increasingly dominated ecosystems within the Okanagan River basin, which spans the Canada–United States border between British Columbia and Washington State. Over the past 50 years, fisheries for anadromous salmon in the Okanagan River basin virtually disappeared as once abundant stocks, such as Sockeye Salmon <i>Oncorhynchus nerka</i>, declined to fewer than 10,000 adults returning annually (on average) in the 1990s. Threat assessments suggested degradation of freshwater habitat in the Columbia River basin as the general cause for the decline. However, recent record returns (2008–2016 average >200,000 adults) indicated surprising resilience and recovery. Review of recent stock management and restoration efforts focused on Okanagan Sockeye Salmon indicated that management actions and fortuitous events facilitated the restoration of salmon to levels exceeding recorded, historic maxima. Actions and events identified include (1) assessment to determine whether large increases in escapement provided evidence of historic underuse of spawning (Okanagan River) and rearing environment (Osoyoos Lake) capacities; (2) development of a decision support system to facilitate fish-friendly water management, which reduced losses of eggs or fry to density-independent events (Okanagan River and Lake); (3) a small contribution (<10% of total production) of hatchery-origin fish; and (4) a coincidental return to favorable marine conditions for Okanagan Sockeye Salmon. Recovery success also involved development of an ecosystem-based sustainability strategy incorporating a shared vision for dealing with human and natural system impacts on salmon from local (Okanagan River basin) to global (North Pacific Ocean) scales. Key elements that characterized efforts to restore Okanagan Sockeye Salmon were the development of ecosystem-based management (including elevated levels of engagement, cooperation, and collaboration among responsible parties to support a common cause); the creation of new knowledge of complex cause-and-effect ecological, economic, and cultural associations; and the creation of new resource management tools (e.g., models and decision support systems). Science-based collaboration to restore aquatic ecosystems and Okanagan salmon is an example of positive outcomes resulting from implementation of Canada’s 2005 Wild Salmon Policy.

2020 ◽  
Vol 77 (10) ◽  
pp. 1721-1732
Author(s):  
Lukas B. DeFilippo ◽  
Daniel E. Schindler ◽  
Kyle Shedd ◽  
Kevin L. Schaberg

With advances in molecular genetics, it is becoming increasingly feasible to conduct genetic stock identification (GSI) to inform management actions that occur within a fishing season. While applications of in-season GSI are becoming widespread, such programs seldom integrate data from previous years, underutilizing the full breadth of information available for real-time inference. In this study, we developed a Bayesian hierarchical model that integrates historical and in-season GSI data to estimate temporal changes in the composition of a mixed stock of sockeye salmon (Oncorhynchus nerka) returning to Alaska’s Chignik watershed across the fishing season. Simulations showed that even after accounting for time constraints of transporting and analyzing genetic samples, a hierarchical approach can rapidly achieve accurate in-season stock allocation, outperforming alternative methods that rely solely on historical or in-season data by themselves. As the distribution and phenology of fish populations becomes more variable and difficult to predict under climate change, in-season management tools will likely be increasingly relied upon to protect biocomplexity while maximizing harvest opportunity in mixed stock fisheries.


Author(s):  
Dayani Bailly ◽  
Valéria Flavia Batista‐Silva ◽  
Fernanda A. Silva Cassemiro ◽  
Priscila Lemes ◽  
Weferson Junio Graça ◽  
...  

2021 ◽  
Vol 13 (4) ◽  
pp. 1775
Author(s):  
Cesar Freddy Suárez ◽  
Monica Paez-Vasquez ◽  
Fernando Trujillo ◽  
Jose Saulo Usma ◽  
Michele Thieme ◽  
...  

The Orinoco river basin is the third largest river in the world by volume. Its catchment encompasses 27 major sub-basins including the Bita with a catchment area of about 825,000 ha, which originates in the Colombian high plains in the Llanos ecoregion. It has been recognized as a priority area for conservation through different gap analyses and overall determined to have good health according to the Orinoco report card 2016. The natural climate and hydrologic processes, and their synergies with flooded forests, savannas, wetlands, species diversity and local economic activities, are part of a dynamic and sensitive system. With the purpose of conserving the ecological, social and cultural benefits that it brings, the Colombian Government, with the support of regional and local civil society organizations, promoted the designation of a conservation area. Technical exercises were carried out including biological and socioeconomic surveys, local stakeholder consultations and future scenario modeling. In June 2018, the Bita River basin was designated as the largest Ramsar site in Colombia, providing a worldwide example of explicit protection of riverine systems. In order to maintain this free-flowing river, land use and fisheries management, in conjunction with other conservation actions, are being implemented and provide a model of protection for freshwater ecosystems that could be replicated elsewhere.


Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1803
Author(s):  
Valentino Palombo ◽  
Elena De Zio ◽  
Giovanna Salvatore ◽  
Stefano Esposito ◽  
Nicolaia Iaffaldano ◽  
...  

Mediterranean trout is a freshwater fish of particular interest with economic significance for fishery management, aquaculture and conservation biology. Unfortunately, native trout populations’ abundance is significantly threatened by anthropogenic disturbance. The introduction of commercial hatchery strains for recreation activities has compromised the genetic integrity status of native populations. This work assessed the fine-scale genetic structure of Mediterranean trout in the two main rivers of Molise region (Italy) to support conservation actions. In total, 288 specimens were caught in 28 different sites (14 per basins) and genotyped using the Affymetrix 57 K rainbow-trout-derived SNP array. Population differentiation was analyzed using pairwise weighted FST and overall F-statistic estimated by locus-by-locus analysis of molecular variance. Furthermore, an SNP data set was processed through principal coordinates analysis, discriminant analysis of principal components and admixture Bayesian clustering analysis. Firstly, our results demonstrated that rainbow trout SNP array can be successfully used for Mediterranean trout genotyping. In fact, despite an overwhelming number of loci that resulted as monomorphic in our populations, it must be emphasized that the resulted number of polymorphic loci (i.e., ~900 SNPs) has been sufficient to reveal a fine-scale genetic structure in the investigated populations, which is useful in supporting conservation and management actions. In particular, our findings allowed us to select candidate sites for the collection of adults, needed for the production of genetically pure juvenile trout, and sites to carry out the eradication of alien trout and successive re-introduction of native trout.


2009 ◽  
Vol 20 (1) ◽  
pp. 62-73 ◽  
Author(s):  
ADRIAN S. DI GIACOMO ◽  
PETER D. VICKERY ◽  
HERNAN CASAÑAS ◽  
OSCAR A. SPITZNAGEL ◽  
CHRISTIAN OSTROSKY ◽  
...  

SummaryThe Aguapey river basin in the Pampas grasslands of Argentina is the last refuge for a complete assemblage of globally threatened and Near Threatened birds. We evaluated the influence of landscape characteristics on the occurrence and abundance of six globally threatened and Near Threatened passerines. We used point counts to census birds and vegetation and quantified landscape characteristics 1,000 m from the count centres using remote sensing tools. Strange-tailed Tyrants Alectrurus risora were associated with higher percentages of tall-grass Andropogon lateralis in lowland areas. Saffron-cowled Blackbirds Xanthopsar flavus and Black-and-white Monjitas Heteroxolmis dominicana were associated with rolling landscape with wet lowland grasslands and marshes linked with dry upland grasslands. Marsh Seedeater Sporophila palustris and Chestnut Seedeater S. cinnamomea were associated with tall grasslands and marshes. Rufous-throated Seedeater S. ruficollis was not clearly associated with any type of habitat. The Aguapey grasslands are used mainly for livestock grazing and afforestation. Since 1995, approximately 50% of the original grassland habitat has been planted with exotic trees. If this trend continues, Saffron-cowled Blackbirds are likely to become extinct in the Aguapey river basin which currently supports the largest population of this species in Argentina. We recommend guidelines for establishing future reserves and wildlife management actions based on the landscape responses detected in this study. Future action should consider: maintaining connectivity between the Aguapey grasslands and the Ibera Nature Reserve, creating a protected area, designing a land use plan for the basin, avoiding afforestation in large blocks, removal of government incentives for large afforestation projects, and studying the viability of threatened bird populations in extensive cattle ranching areas.


2015 ◽  
Vol 19 (3) ◽  
pp. 1457-1467 ◽  
Author(s):  
A. Tilmant ◽  
G. Marques ◽  
Y. Mohamed

Abstract. Many river basins throughout the world are increasingly under pressure as water demands keep rising due to population growth, industrialization, urbanization and rising living standards. In the past, the typical answer to meet those demands focused on the supply side and involved the construction of hydraulic infrastructures to capture more water from surface water bodies and from aquifers. As river basins have become more and more developed, downstream water users and ecosystems have become increasingly dependent on the management actions taken by upstream users. The increased interconnectedness between water users, aquatic ecosystems and the built environment is further compounded by climate change and its impact on the water cycle. Those pressures mean that it has become increasingly important to measure and account for changes in water fluxes and their corresponding economic value as they progress throughout the river system. Such basin water accounting should provide policy makers with important information regarding the relative contribution of each water user, infrastructure and management decision to the overall economic value of the river basin. This paper presents a dynamic water accounting approach whereby the entire river basin is considered as a value chain with multiple services including production and storage. Water users and reservoir operators are considered as economic agents who can exchange water with their hydraulic neighbors at a price corresponding to the marginal value of water. Effective water accounting is made possible by keeping track of all water fluxes and their corresponding hypothetical transactions using the results of a hydro-economic model. The proposed approach is illustrated with the Eastern Nile River basin in Africa.


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