Stranding ahoy? Heterogeneous transition beliefs and capital investment choices

Individuals have heterogeneous beliefs regarding the future speed and shape of the low-carbon transition. In this paper, we study to what extent opinion diversity matters for aggregate capital investment decisions. We develop a model where firms formulate heterogeneous expectations around a dominant narrative, or ‘market norm’, with their dispersion increasing over a finite planning horizon. Our analytical and numerical results suggest that belief heterogeneity can significantly affect the share of low-carbon investments, with the strength of its effects non-linearly correlated to market norms. We show that investment behaviour tends to be more sensitive to shocks to short-term, rather than long-term, belief heterogeneity, highlighting the importance of setting credible short-term targets. Finally, we find beliefs to interact strongly and in non-trivial ways with measures of short-termism, with increasing agents' farsightedness not necessarily leading to less carbon-intensive investments under high heterogeneity.</p

Chill out: physiological responses to winter ice-angling in two temperate freshwater fishes

A large body of research has documented the stress response of fish following angling capture. Nearly all of these studies have taken place during the open-water season, with almost no work focused on the effects of capture in the winter via ice angling. We therefore conducted a study to examine physiological disturbance and reflex impairment following capture by ice-angling in two commonly targeted species, bluegill Lepomis macrochirus and yellow perch Perca flavescens. Fish were captured from a lake in eastern Wisconsin (USA) and sampled either immediately or after being held in tanks for 0.5, 2 or 4 h. Sampling involved the assessment of reflex action mortality predictors (RAMP) and a blood biopsy that was used to measure concentrations of plasma cortisol and lactate. The capture-induced increase in plasma cortisol concentration was delayed relative to responses documented in previous experiments conducted in the summer and reached a relative high point at 4 h post-capture. Reflex impairment was highest at the first post-capture time point (0.5 h) and declined with each successive sampling (2 and 4 h) during recovery. Bluegill showed a higher magnitude stress response than yellow perch in terms of plasma cortisol and RAMP scores, but not when comparing plasma lactate. Overall, these data show that ice-angling induces a comparatively mild stress response relative to that found in previous studies of angled fish. While recovery of plasma stress indicators does not occur within 4 h, declining RAMP scores demonstrate that ice-angled bluegill and yellow perch do recover vitality following capture."This work was supported by Federal Aid in Sport Fish Restoration Project F-69-R-29 to J.A.S."https://academic.oup.com/conphys/article/5/1/cox027/376958

Research and Analysis of Fisheries in Illinois

Reports on progress and results for the following project objectives: sport fish population and sport fishing metrics; enhanced field sampling of sport fish populations; determination of factors affecting fishing quality; coordination with ongoing fisheries research projects; support for and enhance of web interface; fishes of Champaign County; recovery of urban stream sport fisheries.Illinois Department of Natural Resources, Division of Fisheries, Federal Aid Project F-69-R Segment 28unpublishednot peer reviewedOpe

Physiological and behavioral drivers of angling vulnerability in freshwater sportfish

A large body of research has documented evolutionary change in fish populations as a result of selective harvest, a process known as Fisheries-Induced Evolution (FIE). Much of this research has focused on commercially-harvested marine populations, though recent work has also shown that FIE can also occur in freshwater systems targeted by recreational hook-and-line anglers. For FIE to occur as a result of recreational angling, it is necessary that particular traits (for instance, aspects of an individual fish’s behavior or physiology) are associated with an increased likelihood of capture by anglers, leading to selective harvest that causes directional evolution away from that trait. For researchers and managers to accurately predict the outcomes of FIE in freshwater, it is therefore imperative that selected traits are identified, particularly in heavily fished species. While some work has been done previously in this area, several behavioral and physiological characteristics that could be linked with angling vulnerability have yet to be fully explored. In this dissertation, I present a series of experiments examining a set of behavioral and physiological traits and their role in driving angling vulnerability in fish. Each experiment utilizes one of two highly sought-after freshwater species, the largemouth bass Micropterus salmoides or the bluegill Lepomis macrochirus. In each experiment, a given set of characteristics is evaluated in individuals of the species in question, and paired with results from actual angling experiments conducted on those same individuals in a naturalistic pond setting. In chapter 2, I examine the role of boldness, metabolic rate (standard metabolic rate, maximum metabolic rate, and aerobic scope) and stress responsiveness in driving angling vulnerability. A set of largemouth bass from a suite of lines selected for differing vulnerability to angling were assessed for boldness in a standard open-field test. Following this, individuals had blood samples taken before and after an air exposure challenge to assess both baseline and post-stress levels of the primary stress hormone, cortisol. All assessed fish were then stocked into a pond where angling took place. At the conclusion of angling trials, a subset of captured and uncaptured fish were assessed for metabolic rate using intermittent-flow respirometry. Results showed a highly significant association between stress responsiveness and angling vulnerability, specifically that individuals captured by anglers showed a smaller rise in cortisol levels after the air exposure challenge compared to uncaptured fish. Boldness and metabolic rate did not predict angling vulnerability. Because high stress responsiveness has been linked previously to a propensity to freeze in response to challenges (as well as other behavioral traits), selective capture in largemouth bass could lead to evolutionary pressure favoring passive and reactive behavior in exploited systems. In chapter 3, I examined the role of metabolic phenotype in driving angling vulnerability in bluegill. Similar methods were used to assess metabolic rate as in chapter 2, with an additional examination of anaerobic capacity in the form of excess post-exercise oxygen consumption (EPOC). Fish were first angled, with a subset of fish assessed for metabolic phenotype afterwards. Results showed no difference in metrics of metabolic phenotype (standard and maximal metabolic rates, aerobic scope, EPOC, metabolic recovery time) between captured and uncaptured fish, indicating that, in bluegill, metabolic characteristics are likely not under selective pressure from angling. Chapter 4 examined the relationships between individual sociability, aggression, and angling vulnerability in bluegill. For this chapter, bluegill were first subjected to angling, with a subset of captured and uncaptured fish then assessed for sociability and aggression in the laboratory. Assessment for sociability consisted of placing an individual bluegill in a large tank divided in half by a transparent barrier that separated the focal fish from a shoal of conspecifics. Sociability was defined as the time spent by the focal fish near the divider, associating with the conspecifics. Following this, focal fish were size-matched and assessed for aggression and dominance in dyadic trials. Results showed a significant effect of time spent near the divider on angling vulnerability, with captured bluegill being more social than uncaptured bluegill. Aggression was not a significant predictor of vulnerability, though a non-significant trend was found whereby captured fish tended to be less aggressive. While chapter 4 examined bluegill sociability on an individual basis (i.e. each focal fish was examined in isolation), Chapter 5 sought to quantify sociability within the context of interactions within a group of individuals. In addition, swimming performance was assessed for the purpose of determining if this physiological trait was linked with either angling vulnerability or social behavior. For this, groups of 6 individuals were size-matched and placed into a common tank, where they were evaluated for sociability and aggression over three days of observation. Pooled behavior from all three days was then analyzed using methods derived from Social Network Analysis. Each fish was then assessed for swimming performance (critical swimming speed - Ucrit) in a Brett-style swim tunnel before being stocked into a pond for angling. The results showed that, while only fish size predicted whether or not a fish was captured (larger fish were more likely to be caught at least once), more social and less aggressive individuals were found to be the most vulnerable. Specifically, high sociability/low aggression predicted whether an individual was caught multiple times, and also predicted capture order with highly social individuals being captured first. Swimming performance did not predict any aspect of angling vulnerability. These results, combined with the results from chapter 4, indicate that social behavior is indeed a key determinant of angling vulnerability in bluegill, and that angling selection may evolutionarily favor fish that are both more aggressive and less social. In chapter 6, I examined the role of learning performance and proactivity in driving angling vulnerability in largemouth bass. For this experiment, a set of largemouth bass was assessed for learning performance on an active-avoidance task. For this task, each fish was put into an individual tank that was divided in two by an opaque barrier. The barrier included a small opening for shuttling between sides of the tank. Over a set of trials, an observer first shined a light over the fish, which was followed by chasing with an aquarium net. When fish successfully shuttled to the other side of the tank in response to the light (but before the onset of chasing), this was considered successful learning. From there, each fish was assessed for proactivity in a restraint test, where fish were scored based on the number of attempts each fish made to leap from a container when held out of water. Following angling, it was found that learning performance was significantly linked with angling vulnerability, with high performing individuals being more likely to be captured. Within the framework of “cognitive syndromes”, this result indicates that individuals that learn tasks quickly and are, therefore often prone to mistakes, may be under selective pressure in angled populations of largemouth bass. Collectively, this research has identified several behavioral and physiological characteristics that drive vulnerability to angling, however the characteristics differed between species. While largemouth bass vulnerability was driven by characteristics broadly related to proactive behavior (rapid learning, low stress responsiveness), for bluegill it was social and unaggressive individuals that were found to be the most vulnerable. Overall, this means that heavily fished populations could experience behavioral evolution as a result of selective capture on these traits, however the traits under selection may differ depending on the species

USE OF FIRST-ORDER TRIBUTARIES BY BROWN TROUT (SALMO TRUTTA) AS NURSERY HABITAT IN A CENTRAL WISCONSIN COLDWATER STREAM NETWORK

A Thesis Submitted In Partial Fulfillment of the Requirements For the Degree of Master of Science - BiologyMany studies have examined the importance of suitable in-stream habitat and flow regime to salmonid fishes. However, few studies have examined the use of small (< 5 L/s discharge) headwater streams within a larger stream network by trout. The purpose of this study was to evaluate the use of headwater streams by juvenile brown trout Salmo trutta in the Emmons Creek stream network in Wisconsin, USA, and to determine if abundance and body size of trout are related to habitat and food supply in these streams. Fishes in nine spring-fed first-order streams were sampled during a seven month period using a DC backpack electroshocker, identified, and measured for total length. Habitat and biological variables assessed included stream discharge, water velocity, sediment composition, abundance of cover items (woody debris and macrophytes), and benthic macroinvertebrate density. Monthly densities of YOY trout ranged from 0 to 1 per m2 and differed among streams. Regression analyses revealed negative relationships between fish density and discharge and positive association between fish density and % fine sediment among 1st-order streams in the spring (April and May) but not in the summer (July and August), reflecting the results of previous studies of the habitat preferences of trout in larger streams. There was divergence in mean fish length among 1st-order streams as the study period progressed, and in August mean YOY lengths by stream were negatively associated with density. My work demonstrates the viability of small first-order streams as nursery habitat for trout, and supports the inclusion of headwater streams in future conservation and stream restoration efforts

Physiological and behavioral drivers of angling vulnerability in freshwater sportfish

A large body of research has documented evolutionary change in fish populations as a result of selective harvest, a process known as Fisheries-Induced Evolution (FIE). Much of this research has focused on commercially-harvested marine populations, though recent work has also shown that FIE can also occur in freshwater systems targeted by recreational hook-and-line anglers. For FIE to occur as a result of recreational angling, it is necessary that particular traits (for instance, aspects of an individual fish’s behavior or physiology) are associated with an increased likelihood of capture by anglers, leading to selective harvest that causes directional evolution away from that trait. For researchers and managers to accurately predict the outcomes of FIE in freshwater, it is therefore imperative that selected traits are identified, particularly in heavily fished species. While some work has been done previously in this area, several behavioral and physiological characteristics that could be linked with angling vulnerability have yet to be fully explored. In this dissertation, I present a series of experiments examining a set of behavioral and physiological traits and their role in driving angling vulnerability in fish. Each experiment utilizes one of two highly sought-after freshwater species, the largemouth bass Micropterus salmoides or the bluegill Lepomis macrochirus. In each experiment, a given set of characteristics is evaluated in individuals of the species in question, and paired with results from actual angling experiments conducted on those same individuals in a naturalistic pond setting. In chapter 2, I examine the role of boldness, metabolic rate (standard metabolic rate, maximum metabolic rate, and aerobic scope) and stress responsiveness in driving angling vulnerability. A set of largemouth bass from a suite of lines selected for differing vulnerability to angling were assessed for boldness in a standard open-field test. Following this, individuals had blood samples taken before and after an air exposure challenge to assess both baseline and post-stress levels of the primary stress hormone, cortisol. All assessed fish were then stocked into a pond where angling took place. At the conclusion of angling trials, a subset of captured and uncaptured fish were assessed for metabolic rate using intermittent-flow respirometry. Results showed a highly significant association between stress responsiveness and angling vulnerability, specifically that individuals captured by anglers showed a smaller rise in cortisol levels after the air exposure challenge compared to uncaptured fish. Boldness and metabolic rate did not predict angling vulnerability. Because high stress responsiveness has been linked previously to a propensity to freeze in response to challenges (as well as other behavioral traits), selective capture in largemouth bass could lead to evolutionary pressure favoring passive and reactive behavior in exploited systems. In chapter 3, I examined the role of metabolic phenotype in driving angling vulnerability in bluegill. Similar methods were used to assess metabolic rate as in chapter 2, with an additional examination of anaerobic capacity in the form of excess post-exercise oxygen consumption (EPOC). Fish were first angled, with a subset of fish assessed for metabolic phenotype afterwards. Results showed no difference in metrics of metabolic phenotype (standard and maximal metabolic rates, aerobic scope, EPOC, metabolic recovery time) between captured and uncaptured fish, indicating that, in bluegill, metabolic characteristics are likely not under selective pressure from angling. Chapter 4 examined the relationships between individual sociability, aggression, and angling vulnerability in bluegill. For this chapter, bluegill were first subjected to angling, with a subset of captured and uncaptured fish then assessed for sociability and aggression in the laboratory. Assessment for sociability consisted of placing an individual bluegill in a large tank divided in half by a transparent barrier that separated the focal fish from a shoal of conspecifics. Sociability was defined as the time spent by the focal fish near the divider, associating with the conspecifics. Following this, focal fish were size-matched and assessed for aggression and dominance in dyadic trials. Results showed a significant effect of time spent near the divider on angling vulnerability, with captured bluegill being more social than uncaptured bluegill. Aggression was not a significant predictor of vulnerability, though a non-significant trend was found whereby captured fish tended to be less aggressive. While chapter 4 examined bluegill sociability on an individual basis (i.e. each focal fish was examined in isolation), Chapter 5 sought to quantify sociability within the context of interactions within a group of individuals. In addition, swimming performance was assessed for the purpose of determining if this physiological trait was linked with either angling vulnerability or social behavior. For this, groups of 6 individuals were size-matched and placed into a common tank, where they were evaluated for sociability and aggression over three days of observation. Pooled behavior from all three days was then analyzed using methods derived from Social Network Analysis. Each fish was then assessed for swimming performance (critical swimming speed - Ucrit) in a Brett-style swim tunnel before being stocked into a pond for angling. The results showed that, while only fish size predicted whether or not a fish was captured (larger fish were more likely to be caught at least once), more social and less aggressive individuals were found to be the most vulnerable. Specifically, high sociability/low aggression predicted whether an individual was caught multiple times, and also predicted capture order with highly social individuals being captured first. Swimming performance did not predict any aspect of angling vulnerability. These results, combined with the results from chapter 4, indicate that social behavior is indeed a key determinant of angling vulnerability in bluegill, and that angling selection may evolutionarily favor fish that are both more aggressive and less social. In chapter 6, I examined the role of learning performance and proactivity in driving angling vulnerability in largemouth bass. For this experiment, a set of largemouth bass was assessed for learning performance on an active-avoidance task. For this task, each fish was put into an individual tank that was divided in two by an opaque barrier. The barrier included a small opening for shuttling between sides of the tank. Over a set of trials, an observer first shined a light over the fish, which was followed by chasing with an aquarium net. When fish successfully shuttled to the other side of the tank in response to the light (but before the onset of chasing), this was considered successful learning. From there, each fish was assessed for proactivity in a restraint test, where fish were scored based on the number of attempts each fish made to leap from a container when held out of water. Following angling, it was found that learning performance was significantly linked with angling vulnerability, with high performing individuals being more likely to be captured. Within the framework of “cognitive syndromes”, this result indicates that individuals that learn tasks quickly and are, therefore often prone to mistakes, may be under selective pressure in angled populations of largemouth bass. Collectively, this research has identified several behavioral and physiological characteristics that drive vulnerability to angling, however the characteristics differed between species. While largemouth bass vulnerability was driven by characteristics broadly related to proactive behavior (rapid learning, low stress responsiveness), for bluegill it was social and unaggressive individuals that were found to be the most vulnerable. Overall, this means that heavily fished populations could experience behavioral evolution as a result of selective capture on these traits, however the traits under selection may differ depending on the species.U of I OnlyAuthor requested U of Illinois access only (OA after 2yrs) in Vireo ETD syste

Research and Analysis of Fisheries in Illinois Final Performance Report 1 July 2017 – 30 June 2018

Project F-69-R has three overall goals: (1) conduct a wide variety of surveys and investigations that elucidate patterns of variation in sport fish populations and the mechanisms that drive those patterns, (2) communicate research findings and basic assessments of sport fish populations to the angling public, and (3) organize, manage, analyze and deliver sport fisheries data to researchers, sport fish managers, and the angling public. Basic and applied research studies, public outreach efforts, and data management activities all work in concert to create a better understanding of the restoration and conservation needs of sport fish populations in Illinois.Illinois Department of Natural Resources, Division of Fisheriesunpublishednot peer reviewedOpe

Research and Analysis of Fisheries in Illinois Final Performance Report 1 July 2016 – 30 June 2017

Project F-69-R has three overall goals: (1) conduct a wide variety of surveys and investigations that elucidate patterns of variation in sport fish populations and the mechanisms that drive those patterns, (2) communicate research findings and basic assessments of sport fish populations to the angling public, and (3) organize, manage, analyze and deliver sport fisheries data to researchers, sport fish managers, and the angling public. Basic and applied research studies, public outreach efforts, and data management activities all work in concert to create a better understanding of the restoration and conservation needs of sport fish populations in Illinois.Illinois Department of Natural Resources, Division of Fisheriesunpublishednot peer reviewedOpe