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1. Juvenile Albacore tuna ( Thunnus alalunga ) foraging ecology varies with environmental conditions in the California Current Large Marine Ecosystem

   https://doi.org/10.1111/fog.12638  

   Nickels, Catherine F. ; Portner, Elan J. ; Snodgrass, Owyn ; Muhling, Barbara ; Dewar, Heidi ( September 2023 , Fisheries Oceanography)

   Juvenile North Pacific Albacore tuna (Thunnus alalunga) support commercial and recreational fisheries in the California Current Large Marine Ecosystem (CCLME), where they forage during summer and fall. The distributions of the commercial and recreational fisheries and estimates of forage availability have varied substantially over the past century. Time‐series quantifying Albacore diet can help link forage composition to variability in Albacore abundance and distribution and, consequently, their availability to fishers. Previous diet studies in the CCLME are of relatively short duration, and long‐term variability in Albacore diet remains poorly understood. We describe the diets of juvenile Albacore from three regions in the CCLME from 2007 to 2019 and use classification and regression tree analysis to explore environmental drivers of variability. Important prey include Northern Anchovy (Engraulis mordax), rockfishes (Sebastesspp.), Boreal Clubhook Squid (Onychoteuthis borealijaponica), euphausiids (Order: Euphausiidae), and amphipods (Order: Amphipoda), each contributing >5% mean proportional abundance. Most prey items were short lived species or young‐of‐the‐year smaller than 10 cm. Diet variability was related to environmental conditions over the first 6 months of the year (PDO, sea surface temperature, and NPGO) and conditions concurrent with Albacore capture (region and surface nitrate flux). We describe foraging flexibility over regional and annual scales associated with these environmental influences. Continuous, long‐term studies offer the opportunity to identify flexibility in Albacore foraging behavior and begin to make a predictive link between environmental conditions early in the year and Albacore foraging during summer and fall.

    

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2. Population structure of giant clams (subfamily: Tridacninae) across Palau: Implications for conservation

   https://doi.org/10.1002/aqc.3758  

   Rehm, Lincoln ; Marino, Lincy L. ; Jonathan, Randa ; Holt, Amanda L. ; McCourt, Richard M. ; Sweeney, Alison M. ( December 2021 , Aquatic Conservation: Marine and Freshwater Ecosystems)

   Giant clams (subfamily: Tridacninae) are an important food and economic resource for the Republic of Palau and the greater Indo‐Pacific region. However, giant clam diversity and distribution data for Palau are out of date.

   This study reports the species diversity and distribution of giant clams across the Palauan archipelago (total survey area of 3,300²m) from data collected between 2015–2017.

   This is the first documented finding ofTridacna noaein Palau, however, it was rare. Only four individuals were found at only two locations.

   Results show that Palau is home to a diverse and abundant population of giant clams.Tridacna crocea(an important food and economic resource) exhibited the highest abundance, with an average of 20.0 ± 2.9 individuals per 50 m².Tridacna maximaandTridacna squamosawere ranked next in abundance. In contrast,T. noae,Tridacna derasa,Tridacna gigas, andHippopus hippopuswere found in low numbers or only found in few locations.

   The density of all recruits, juveniles, and adultT. croceaandT. maximadid not differ significantly between conservation areas and open fishing sites, which suggests the possibility that ecological factors such as habitat loss, acute weather events, or changes in sea surface temperatures could be impacting replenishment or recruitment. However, one protected area was found to have a higher abundance ofT. crocearecruits and adults, which suggests that protection from fishing may have increased recruitment rates and lowered mortality rates at this site.

   Taken as a whole, clam populations in Palau remain reasonably abundant and healthy. As demand for giant clams continues to rise in Palau and the region, local regulations should focus on sustainable fishing practices by establishing size limits, species bans, and long‐term monitoring plans to maintain the diverse populations of giant clams found there.

    

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3. Sustainability metrics for assessing water resource recovery facilities of the future

   https://doi.org/10.2175/106143017X15131012187980  

   Cornejo, Pablo K. ; Becker, Jennifer ; Pagilla, Krishna ; Mo, Weiwei ; Zhang, Qiong ; Mihelcic, James R. ; Chandran, Kartik ; Sturm, Belinda ; Yeh, Daniel ; Rosso, Diego ( January 2019 , Water Environment Research)

   The recovery of water, energy, and nutrients from water resource recovery facilities (WRRFs) is needed to address significant global challenges, such as increasing water demand and decreasing availability of nonrenewable resources. To meet these challenges, innovative technological developments must lead to increased adoption of water and resource recovery processes, while addressing stakeholder needs (e.g., innovators, practitioners, regulators). A test bed network of over 90 partner facilities within the United States and abroad will help accelerate innovation and widespread adoption of novel processes through multiscale testing and demonstration of technologies. In this paper, we define a common set of environmental, economic, technical, and social performance metrics for innovative technologies, that will meet the needs of multiple stakeholders in the decision‐making process. These triple bottom line performance metrics can be used to track the sustainability of technologies in a consistent and transparent manner, while aiding the decision‐making process forWRRFs.

   The Facilities Accelerating Science and Technology (FAST) Water Network includes over 90 test bed facilities dedicated to accelerating innovation and adoption of water energy, and nutrient recovery systems.

   A common set of environmental, economic, technical, and social performance metrics should be measured and reported when a new technology is evaluated in the FAST Water Network.

   Performance metrics can aid sustainable decision‐making at WRRF, while meeting the needs of multiple stakeholders.

    

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4. Estimating the effects of non‐native species on nutrient recycling using species‐specific and general allometric models

   https://doi.org/10.1111/fwb.13092  

   Fritschie, Keith J. ; Olden, Julian D. ( February 2018 , Freshwater Biology)

   Non‐native species are now common in community assemblages, but the influence of multiple introductions on ecosystem functioning remains poorly understood. In highly invaded systems, one promising approach is to use functional traits to scale measured individuals’ effects on ecosystem function up to the community level. This approach assumes that functional traits provide a common currency among species to relate individuals to ecosystem functioning.

   The goals of this study were to (i) test whether the relationship between body size and ecosystem functioning (per capita nutrient recycling) was best described by general or species‐specific scaling models; (ii) relate community structure (total biomass, average body size, non‐native dominance) to aggregated, community‐level nutrient recycling rates and ratios; and (iii) determine whether conclusions regarding the relationships between community structure and aggregate ecosystem functioning differed between species‐specific and general scaling approaches.

   By combining experimental incubations and field surveys, we compare consumer‐mediated nutrient recycling of fish communities along a non‐native dominance gradient in the Verde River watershed of central Arizona,USA. Data from ˜340 field‐sampled freshwater fish demonstrated support for general allometric relationships predicted by the metabolic theory of ecology (NH₄‐N scaling coefficient = 0.72 [0.64–0.80];PO₄‐P = 0.67 [0.47–0.86]). However, the best‐fit models for N and P included species‐specific random effects for both allometric slopes and intercepts.

   According to species‐specific models, stream fish communities recycled 1–12 mmolNH₄‐N/hr (median = 2.8 mmol/hr) and 0.02–0.74 mmolPO₄‐P/hr (median = 0.07 mmol/hr) at N:P ratios between 13.3 and 83.5 (median = 28.8). General models generated similar estimates forNH₄‐N recycling but less accurate estimates forPO₄‐P. Stochastic simulations that incorporated error around allometric parameter estimates led to qualitatively similar but larger differences between general and species‐specific results.

   Community structure influenced aggregate nutrient recycling, but specific conclusions depended on the scaling approach. Total biomass explained much of the among‐community variation in aggregateNH₄‐N andPO₄‐P for both model types, whereas non‐native dominance alone best predicted variation in aggregate N:P. Surprisingly, species‐specific and general models both reached significant yet quantitatively opposing conclusions regarding the relationship between N:P supply and non‐native dominance.

   Study results indicate that shifting fish community structure can substantially alter ecosystem functioning in this river system. However, some inferred relationships between community structure and aggregate nutrient recycling varied depending on whether general or species‐specific scaling approaches were taken. Although trait‐based approaches to link environmental change, community structure and ecosystem function hold much promise, it will be important to consider when species‐specific versus general models are necessary to scale from individuals to ecosystems.

    

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5. Local fishery, global commodity: the role of institutions in mediating intersectoral conflict, cooperation, and competition in a globalized fishery

   https://doi.org/10.1088/1748-9326/acdca8  

   Seto, Katherine L. ; Aheto, Denis Worlanyo ; Kwadjosse, Theodore ; O’Neill, Kate ( July 2023 , Environmental Research Letters)

   Commons scholarship has improved our understanding of how to govern resources for sustainability. However, it has also been critiqued for its focus on traits (e.g. well-defined system boundaries) that are increasingly threatened by social and environmental trends. Fisheries are a key example of this challenge. While small-scale fisheries are critically important to the diets and livelihoods of millions, industrial fisheries from developed countries now dominate fishing around the world. While these two systems are governed separately, there is substantial overlap between them, conceptualized as the growing influence of globalization on local common pool resource (CPR) systems. One of the most impactful, but least understood consequences of this convergence are the emerging conflicts and competition between small-scale and industrial fisheries. In these systems, the interaction between small-scale CPRs and globalized commodity chains has meant the creation of a new, hybrid resource system, addressed by neither conventional industrial nor traditional small-scale governance approaches. We use empirical data from 396 cases of interactions at sea between globalized industrial and local small-scale fishers in Ghana from 1984 to 2013 to examine the conditions under which resource users conflict or cooperate, linking them to broader political and economic dynamics across scales. We consider the institutional factors that mediate these interactions, identifying policies to promote cooperative, and avert conflictual incidents. We further consider the long-term effects of these patterns of conflict and cooperation for the resilience or vulnerability of the resource base, the fishers, and the institutions governing the system. We suggest that specific governance arrangements that reduce disparities between groups, promote bridging social capital, and enhance hybrid and cross-scale institutions offer the best potential to govern resource systems where traditional CPRs and market-oriented industries converge.

    

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