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The Influence of Projected Outcomes on Preferences over Alternative Regulations: Evidence from a Recreational Fishery
No full textThe expected outcomes arising from alternative policies on respondent choice have not been sufficiently accounted for in stated preference studies. We accordingly develop a framework to quantitatively assess the influence of outcome provision and illustrate with a choice experiment in a recreational fishery. The application suggests that participants are more likely to choose the status quo and low-cost options when outcomes are not provided, and these conservative behaviors might reflect the higher dispersion in anglers’ utility in tautog (Tautoga onitis) fishing. Further investigations with latent class models suggest that the outcome provision makes a significant share of respondents changing their choice patter
Balancing Ecosystems, Harvests, and Seafood Markets
No full textRecognition of competition and predator–prey interactions among species has led some to promote the concept of balanced harvesting, whereby fisheries would remove a proportional, sustainable fraction of all species in the fish community. Practical implementation of such a strategy hinges on understanding the current degree of species selection in fisheries and the factors that drive this selection. This interdisciplinary study measured ecosystem–market symmetry in the New England region by tracking species composition from ecosystem production, to catch, landings, and seafood markets. Strong species selection occurred in the catch and in seafood markets but not by discarding, which suggests that that requiring full retention of all species caught may make a limited contribution to promoting ecosystem–market symmetry. Results from a group of citizen scientists indicate that higher priced species were generally more available in seafood markets and that availability diminished rapidly with distance from shore. We conclude that market-based selection may be reduced through a combination of locavore consumer education and global marketing strategies
The expanded inhibitor of apoptosis gene family in oysters possesses novel domain architectures and may play diverse roles in apoptosis following immune challenge
Get PDFBackground: Apoptosis plays important roles in a variety of functions, including immunity and response to environmental stress. The Inhibitor of Apoptosis (IAP) gene family of apoptosis regulators is expanded in molluscs, including eastern, Crassostrea virginica, and Pacific, Crassostrea gigas, oysters. The functional importance of IAP expansion in apoptosis and immunity in oysters remains unknown.
Results: Phylogenetic analysis of IAP genes in 10 molluscs identified lineage specific gene expansion in bivalve species. Greater IAP gene family expansion was observed in C. virginica than C. gigas (69 vs. 40), resulting mainly from tandem duplications. Functional domain analysis of oyster IAP proteins revealed 3 novel Baculoviral IAP Repeat (BIR) domain types and 14 domain architecture types across gene clusters, 4 of which are not present in model organisms. Phylogenetic analysis of bivalve IAPs suggests a complex history of domain loss and gain. Most IAP genes in oysters (76% of C. virginica and 82% of C. gigas), representing all domain architecture types, were expressed in response to immune challenge (Ostreid Herpesvirus OsHV-1, bacterial probionts Phaeobacter inhibens and Bacillus pumilus, several Vibrio spp., pathogenic Aliiroseovarius crassostreae, and protozoan parasite Perkinsus marinus). Patterns of IAP and apoptosis-related differential gene expression differed between the two oyster species, where C. virginica, in general, differentially expressed a unique set of IAP genes in each challenge, while C. gigas differentially expressed an overlapping set of IAP genes across challenges. Apoptosis gene expression patterns clustered mainly by resistance/susceptibility of the oyster host to immune challenge. Weighted Gene Correlation Network Analysis (WGCNA) revealed unique combinations of transcripts for 1 to 12 IAP domain architecture types, including novel types, were significantly co-expressed in response to immune challenge with transcripts in apoptosis-related pathways.
Conclusions: Unprecedented diversity characterized by novel BIR domains and protein domain architectures was observed in oyster IAPs. Complex patterns of gene expression of novel and conserved IAPs in response to a variety of ecologically-relevant immune challenges, combined with evidence of direct co-expression of IAP genes with apoptosis-related transcripts, suggests IAP expansion facilitates complex and nuanced regulation of apoptosis and other immune responses in oysters
A crew-operated data recording system for length-based stock assessment of Indonesia’s deep demersal fisheries
Get PDFDeep demersal fisheries in Indonesia yielded close to 90,000 metric tons of snapper and grouper in 2019, landed by a fleet of approximately 10,000 fishing boats. Prior to the present study, information on these multi-species, dispersed, small- to medium-scale fisheries was scarce, while reliable species-specific data on catch and effort were non-existent. This data-deficiency made stock assessments and design of harvest control rules impossible. We developed a new data collection method, the Crew Operated Data Recording System (CODRS), to collect verifiable species- and length-composition data from catches across all segments of the fleet. CODRS engaged crews of 579 fishing vessels to take pictures of each fish in their catch, in combination with the deployment of a tracking device on their boats. Furthermore, we also conducted a frame survey to map the fleet across the entire Indonesian archipelago. Using more than 2 million CODRS images, we aimed to understand the basic characteristics and challenges within the fishery. We updated life-history parameters for the top 50 species in the fishery based on the maximum observed length-frequency distribution of the catch (i.e., asymptotic length, size at maturity, optimum fishing length, total mortality, and spawning potential ratio). Length-based stock assessments using the updated life-history parameters showed high risks of overfishing for most of the major target species, especially for snapper species with large maximum sizes. Our results indicated that effective management and harvest strategies are urgently needed across Indonesia’s eleven Fishery Management Areas to prevent the collapse of these important fisheries
Responses in fisheries catch data to a warming ocean along a latitudinal gradient in the western Pacific Ocean
No full textOcean warming has been affecting marine ecosystems over the past few decades. The signature of ocean warming in global fisheries catch data has been identified through a variety of methods, one of which is the mean temperature of the catch (MTC) index. The MTC is derived from the average temperature preference of fished species weighted by their contribution to annual catches. Here, we used MTC to explore the fisheries catch responses to warming, from 1950 to 2016, along a latitudinal gradient in the western Pacific Ocean, from 37° N, via 2.5° S in the central western Pacific, to 36° S. The tropicalization of catches in a given geographic space, i.e., the increased catch of species with affinity to warmer waters, as a result of increasing sea temperature and the associated poleward migration of species, rather than any large-scale oceanographic variability, was apparent through the increasing MTC at higher latitudes. In particular, MTC in temperate Japan increased by 0.33 °C per decade over the time series. The MTC in subtropical/temperate southeast Australia increased by 0.24 °C per decade over the full time period and by 1.24 °C per decade after 2002. The observed MTC increase was caused by the increasing dominance of thermophilous (preferring warmer waters) over psychrophilous (preferring cooler waters) taxa in the catches in these waters. On the other hand, the MTC in tropical Indonesian waters, as well as the ratio of thermophilous to psychrophilous taxa, showed a gentle yet consistent decrease of 0.05 °C per decade over the full time period. This finding supports the tropicalization hypothesis, given the limited scope for further tropicalization of catches in the already tropical ecosystem of Indonesia. Ocean warming has indeed been altering the distribution of marine organisms, particularly in temperate ecosystems as thermophilous taxa become more abundant, while psychrophilous taxa abundance decreases. Tropicalization impacts fisheries and catch composition and is, therefore, expected to cause conflicts among fishers and challenge fisheries management
Increasing risk of cascading hazards in the central Himalayas
No full textCascading hazards are becoming more prevalent in the central Himalayas. Primary hazards (e.g., earthquakes, avalanches, and landslides) often trigger secondary hazards (e.g., landslide dam, debris flow, and flooding), compounding the risks to human settlements, infrastructures, and ecosystems. Risk management strategies are commonly tailored to a single hazard, leaving human and natural systems vulnerable to cascading hazards. In this commentary, we characterize diverse natural hazards in the central Himalayas, including their cascading mechanisms and potential impacts. A scientifically sound understanding of the cascading hazards, underlying mechanisms, and appropriate tools to account for the compounding risks are crucial to informing the design of risk management strategies. We also discuss the need for an integrated modeling framework, reliable prediction and early warning system, and sustainable disaster mitigation and adaptation strategies
Incorporating fishers’ evaluation of adaptive capacity in policy making in Thailand
No full textSmall-scale fishers around the world are facing many challenges in sustaining viable livelihoods due to diverse factors such as declining fisheries resources, degradation of coastal habitats, and climate change impact, among others. How fishers respond to change depends in part on their evaluations of adaptive capacity, and an understanding of factors underlying their evaluations can be helpful in guiding policies and programs to reduce vulnerability and build resilience. The paper presents a study of twelve small-scale fishing communities in eastern Thailand, which illustrates the multiplicity of factors influencing attitudes, beliefs, values and cognitive biases (ABVCs) concerning adaptive capacity. First, the ABVCs of small-scale fishers toward adaptation to changes and the reduction of fishery resources were elicited using a structured survey. Next, principle component analysis was performed on the survey results of 266 respondents, which revealed that the ABVCs concerning adaptive capacity are related to three main components: ability to change occupation (Options component), ability to compete (Ability component), and ability to plan for changes (Plan component). The final step identified factors influencing the adaptive capacity components with the use of regression analysis. Specifically, the ability to change work is positively related to level of education, and negatively associated with age and high dependency on fishing income. Satisfaction with income and with individual well-being determine the ability to compete. The ability to plan for changes, on the other hand, is influenced by evaluated level of closeness to nature, the factor that is expected to be associated with conservation behavior. The findings can aid in designing policies and interventions that align with the adaptive capacity of fishers; hence, enhancing viability and contributing to increasing resilience of small-scale fishing communities
Effects of relic low-head dams on stream denitrification potential: seasonality and biogeochemical controls
No full textThe majority of dams in the contiguous United States are small, low-head dams that are no longer operational but can influence the water quality of contemporary stream ecosystems. Potential effects of low-head dams on stream nitrogen removal (denitrification) have been rarely quantified, and yet they can be an important part of the decision-making process of removing low-head dams. Here, we provide novel empirical data on potential denitrification rates and their biogeochemical controls above and below two mid-Atlantic low-head dams over a 2-year period. Our results show that low-head dams did not increase streambed potential denitrification in comparison to dam-free sections in the same rivers. In our study sites, potential denitrification above low-head dams was generally low (15.7 ± 3.5 µg N [kg sediment]−1 h−1) despite recurring events of water hypoxia (\u3c 50% dissolved oxygen saturation) and high NO3− and DOC concentrations. Overall, we observed higher potential denitrification during winter samplings (9.2 and 50.1 µg N [kg sediment]−1 h−1 on average) and significant effects of sediment surface area and organic matter content on potential denitrification rates above the dams. Results from this study suggest limited effects of relic low-head dams on nitrogen removal and transport in stream ecosystems, and can contribute to the decision-making process of removing low-head dams
Backed-Up, Saturated, and Stagnant: Effect of Milldams on Upstream Riparian Groundwater Hydrologic and Mixing Regimes
No full textHow milldams alter riparian hydrologic and groundwater mixing regimes is not well understood. Understanding the effects of milldams and their legacies on riparian hydrology is key to assessing riparian pollution buffering potential and for making appropriate watershed management decisions. We examined the spatiotemporal effects of milldams on groundwater gradients, flow directions, and mixing regime for two dammed sites on Chiques Creek, Pennsylvania (2.4 m tall milldam), and Christina River, Delaware (4 m tall dam), USA. Riparian groundwater levels were recorded every 30 min for multiple wells and transects. Groundwater mixing regime was characterized using 30-min specific conductance data and selected chemical tracers measured monthly for about 2 years. Three distinct regimes were identified for riparian groundwaters—wet, dry, and storm. Riparian groundwater gradients above the dam were low but were typically from the riparian zone to the stream. These flow directions were reversed (stream to riparian) during dry periods due to riparian evapotranspiration losses and during peak stream flows. Longitudinal (parallel to the stream) riparian flow gradients and directions also varied across the hydrologic regimes. Groundwater mixing varied spatially and temporally between storms and seasons. Near-stream groundwater was poorly flushed or mixed during storms whereas that in the adjacent swales revealed greater mixing. This differential groundwater behavior was attributed to milldam legacies that include: berm and swale topography that influenced the routing of surface waters, varying riparian legacy sediment depths and hydraulic conductivities, evapotranspiration losses from riparian vegetation, and runoff input from adjoining roads
Filial Norms, Altruism, and Reciprocity: Financial Support to Older Parents in China
Get PDFAs a direct expression of filial piety, adult children, in particular sons, are expected to provide support to older parents in China. Despite concerns about a decline in traditional values, few empirical studies examine whether adherence to Confucian family values impacts adult children’s financial support of aging parents, or if other factors play a more central role. In the present study, I assess several categories of factors including filial piety, altruism, long-term reciprocity, and contemporary mutual exchange. Survey data from the 2002 wave of the Chinese Survey of Family Dynamics (CSFD) (N = 3768) was utilized. For both sons and daughters, agreement with filial piety values, parents’ education level and help with housework were associated with greater likelihood of economic support. For daughters, those with young children (under 18) were less likely to support parents. Among sons, those who received support from parents earlier in the life course (a wedding gift) were more likely to provide financial transfers