... as Forage in the Ecosystem: The Demand for Ecosystem Valuation

Birds, mammals, and fish eat Atlantic Herring. For the first time, fisheries managers in New England are explicitly considering these, and other, predators when setting harvest control rules for the Atlantic Herring fishery. Based on single-species biological reference points, the herring stock is currently well above MSY levels. However, management of this small, oily fish has been quite contentious; many diverse stakeholder groups have recently pushed for increased regulations and lower quotas in the herring fishery. As part of the process, stakeholders identified a diverse suite of metrics needed to assess the performance of a candidate harvest control rule. These metrics included body weight of bluefin tuna, productivity of common terns, biomass of spiny dogfish, and stability of revenues in the herring fishery. A simulation model was then constructed to examine the long-run effects of different harvest control rules on herring stocks, three predators, and the herring fishery. Making sense of the deluge of performance metrics is difficult. Informing this debate is the dream for an applied economist. Bioeconomic theory of predator-prey systems provides a useful framework for thinking about the value of “herring as forage in the ecosystem.” Ecosystem Services Valuation can operationalize this framework. ESV can also simplify the decision-making process by converting diverse model outputs to a standardized unit of measure. Yet minimal, if any, ESV methods were used to inform fisheries managers. We discuss areas where ESV could have been included more prominently and the barriers to truly realizing that dream

WORKSHOP ON GUIDELINES FOR MANAGEMENT STRATEGY EVALUATIONS (WKGMSE2)

The purpose of the meeting was to bring up to date the methodologies and technical specifications that should be incorporated in Management Strategy Evaluation (MSE) work in ICES. The workshop was tasked with reviewing recent methodological and practical MSE work conducted in ICES and around the world, as well as the guidelines provided by the 2013 ICES Workshop on Guidelines for Management Strategy Evaluations (WKGMSE). The Terms of Reference indicated that the revision should include all aspects involved in MSE, while paying specific attention to several issues that had been identified through ICES practice. The Terms of Reference also requested WKGMSE 2 to consider how best to disseminate the guidelines to experts within the ICES community and the need for training courses. The workshop addressed all its Terms of Reference. The main results of the workshop are the revised MSE guidelines, as well as recommendations in relation to the ICES criterion for defining a management strategy as precautionary and in relation to the evaluation and advice on rebuilding strategies.publishedVersio

Management Strategy Evaluation: Allowing the Light on the Hill to Illuminate More Than One Species

Management strategy evaluation (MSE) is a simulation approach that serves as a “light on the hill” (Smith, 1994) to test options for marine management, monitoring, and assessment against simulated ecosystem and fishery dynamics, including uncertainty in ecological and fishery processes and observations. MSE has become a key method to evaluate trade-offs between management objectives and to communicate with decision makers. Here we describe how and why MSE is continuing to grow from a single species approach to one relevant to multi-species and ecosystem-based management. In particular, different ecosystem modeling approaches can fit within the MSE process to meet particular natural resource management needs. We present four case studies that illustrate how MSE is expanding to include ecosystem considerations and ecosystem models as ‘operating models’ (i.e., virtual test worlds), to simulate monitoring, assessment, and harvest control rules, and to evaluate tradeoffs via performance metrics. We highlight United States case studies related to fisheries regulations and climate, which support NOAA’s policy goals related to the Ecosystem Based Fishery Roadmap and Climate Science Strategy but vary in the complexity of population, ecosystem, and assessment representation. We emphasize methods, tool development, and lessons learned that are relevant beyond the United States, and the additional benefits relative to single-species MSE approaches

Considerations for management strategy evaluation for small pelagic fishes

Management strategy evaluation (MSE) is the state-of-the-art approach for testing and comparing management strategies in a way that accounts for multiple sources of uncertainty (e.g. monitoring, estimation, and implementation). Management strategy evaluation can help identify management strategies that are robust to uncertainty about the life history of the target species and its relationship to other species in the food web. Small pelagic fish (e.g. anchovy, herring and sardine) fulfil an important ecological role in marine food webs and present challenges to the use of MSE and other simulation-based evaluation approaches. This is due to considerable stochastic variation in their ecology and life history, which leads to substantial observation and process uncertainty. Here, we summarize the current state of MSE for small pelagic fishes worldwide. We leverage expert input from ecologists and modellers to draw attention to sources of process and observation uncertainty for small pelagic species, providing examples from geographical regions where these species are ecologically, economically and culturally important. Temporal variation in recruitment and other life-history rates, spatial structure and movement, and species interactions are key considerations for small pelagic fishes. We discuss tools for building these into the MSE process, with examples from existing fisheries. We argue that model complexity should be informed by management priorities and whether ecosystem information will be used to generate dynamics or to inform reference points. We recommend that our list of considerations be used in the initial phases of the MSE process for small pelagic fishes or to build complexity on existing single-species models.publishedVersio

Evaluating Methods of Estimating Walleye Angling Exploitation in Northern Wisconsin Lakes

Creel Surveys are used by the WDNR and GLIFWC to estimate walleye (Sander vitreus) angling exploitation rate, but are expensive and time consuming, and the assumptions of these methods have not been tested. The objectives of this thesis were to determine: (1) if angler use and success varied among hours, months, and years during 1991-2002 in northern Wisconsin lakes: (2) if creel survey efficiency could be improved by reallocating sampling effort within months to minimize bias and maximize precision of estimates of walleye angling effort, harvest, harvest rate, and exploitation rate in northern Wisconsin lakes; and (3) if estimates of exploitation rate of walleyes in Wisconsin were biased by lack of mark recognition or fin regeneration. To achieve my first objective, I examined trends in the average number of complete-trip interviews, effort per acre, numbers of walleyes harvested per angler hour, and numbers of walleyes harvested per acre among hours, seasons, and years during 1991-2002 in northern Wisconsin lakes. The average number of complete-trip interviews within days was higher on weekends than weekdays during the open-water and ice-fishing seasons, and trends within days differed between seasons. The average number of walleyes harvested per hour and trends within days were similar on weekends and weekdays and during open-water and ice-fishing seasons. Average angling effort per acre was higher on weekdays than weekends, and trends during the angling season differed between day types. The average number of walleyes harvested per hour was similar on weekends and weekdays, but trends differed between day types during the angling season. Average harvest per acre and trends during the angling season were similar on weekends and weekdays. Effort per acre, walleye harvested per hour, and walleye harvested per acre were similar between day types, and did not change significantly during 1991-2002. Angler use and success in northern Wisconsin lakes changed systematically within days and among seasons, but not among years during 1991-2002, which suggests that the walleye fishery was stable during that period in northern Wisconsin lakes. To achieve my second objective, I compared estimates of effort, harvest rate, harvest, RIC ratio, and recaptures from four reductions in sampling effort (one week per month, two weeks per month, odd numbered weeks, even numbered weeks) in each month of the angling season to estimates from full creel surveys during 1991-2002. Estimates and variances of effort, harvest rate, harvest, RIC ratio, and recaptures from the four reductions in sampling effort were significantly different than those from the full sampling effort in several months for nearly all reductions in sampling effort. I conclude that creel survey efficiency could only be improved if losses in accuracy and precision are acceptable to those who use creel survey estimates for making policy decisions. To achieve my third objective, I estimated the recapture rate, RIC ratio, of walleyes previously marked for each month during the angling year for five length categories of walleye: all lengths combined,< 12 inches, 12-15 inches, 15-20 inches, and~ 20 inches. The RIC ratio declined significantly for all length categories except for fish 12-15 inches long. I conclude that fin regeneration or increased mortality due to marking may have reduced the number of marks in the RIC ratio, and therefore may have biased estimates of walleye angling exploitation rate

Spatial-spectrum estimation and filtering of radio frequency arrays via elemental photonic up-conversion and coherent optical processing

Prather, Dennis W.A method for imaging Radio-frequency (RF) side-bands about an optical carrier signal, previously devised for passive, non-coherent, imaging of millimeter wave radiation is furthered for use in coherent reception of Radio-frequency signals. Theoretical formulation of a novel photonic beam-space beam-former is presented along with relationships to traditional beam-space array theory. The photonic beam-forming system requires each element of a Radio-Frequency (RF) array be optically up-converted to a laser carrier frequency and fed through a photonic processing system, where the output beam-space is sampled using an array of photo-detectors (or a commercial camera). Specic contributions of this work allow for a more power ecient optical system, amplitude calibration of the optical chain, arbitrary apodization (or tapering) of the output beam-space and application of the receiver system to multiple simultaneous domains (e.g. active sensing and communications in one receive array). Furthermore, a novel adaptive weighting approach is presented that utilizes outputs from both a commercial camera device and an array of high-speed photo-detectors to enable array adaptivity that is shown to be of low-latency when compared to existing techniques. Several experiments are performed using prototype hardware to characterize the system, component and algorithm-level performance enabling more capable designs within future work.University of Delaware, Department of Electrical and Computer EngineeringPh.D

Environmental drivers and trends in forage fish occupancy of the Northeast US shelf

© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Suca, J. J., Deroba, J. J., Richardson, D. E., Ji, R., & Llopiz, J. K. Environmental drivers and trends in forage fish occupancy of the Northeast US shelf. Ices Journal of Marine Science, 78(10), (2021): 3687–3708, https://doi.org/10.1093/icesjms/fsab214.The Northeast US shelf ecosystem is undergoing unprecedented changes due to long-term warming trends and shifts in regional hydrography leading to changes in community composition. However, it remains uncertain how shelf occupancy by the region's dominant, offshore small pelagic fishes, also known as forage fishes, has changed throughout the late 20th and early 21st centuries. Here, we use species distribution models to estimate the change in shelf occupancy, mean weighted latitude, and mean weighted depth of six forage fishes on the Northeast US shelf, and whether those trends were linked to coincident hydrographic conditions. Our results suggest that observed shelf occupancy is increasing or unchanging for most species in both spring and fall, linked both to gear shifts and increasing bottom temperature and salinity. Exceptions include decreases to observed shelf occupancy by sand lance and decreases to Atlantic herring's inferred habitat suitability in the fall. Our work shows that changes in shelf occupancy and inferred habitat suitability have varying coherence, indicating complex mechanisms behind observed shelf occupancy for many species. Future work and management can use these results to better isolate the aspects of forage fish life histories that are important for determining their occupancy of the Northeast US shelf.Funding came from the National Oceanic and Atmospheric Administration Woods Hole Sea Grant Program (NA18OAR4170104, Project number R/O-57; RJ and JKL) and a National Science Foundation Long-term Ecological Research grant for the Northeast US Shelf Ecosystem (OCE1655686; RJ and JKL). JJS was funded by the National Science Foundation Graduate Research Fellowship program