Martha E. Mather

Migration delays caused by anthropogenic barriers: modeling dams, temperature, and success of migrating salmon smolts

Disruption to migration is a growing problem for conservation and restoration of animal populations. Anthropogenic barriers along migration paths can delay or prolong migrations, which may result in a mismatch with migration-timing adaptations. To understand the interaction of dams (as barriers along a migration path), seasonally changing environmental conditions, timing of Atlantic salmon (Salmo salar) downstream migration, and ultimate migration success, we used 10 years of river temperature and discharge data as a template upon which we simulated downstream movement of salmon. Atlantic salmon is a cool-water species whose downstream migrating smolts must complete migration before river temperatures become too warm. We found that dams had a local effect on survival as well as a survival effect that was spatially and temporally removed from the encounter with the dam. While smolts are delayed by dams, temperatures downstream can reach lethal or near-lethal temperatures; as a result, the match between com...

Assessing the contribution of anadromous herring to largemouth bass growth

Abstract Juvenile anadromous river herring (alewife Alosa pseudoharengus and blueback herring A. aestivalis) spend the first 3 to 7 months of life in headwater lakes of coastal systems. Systems that support herring often produce trophy largemouth bass Micropterus salmoides. Even though biologists, managers, and anglers have speculated about the value of anadromous herring as a key prey for resident predators, the contribution that herring make to the diets of these predators has not been assessed. Herein, we quantified largemouth bass diets in two coastal lakes, Santuit and Coonamessett ponds, that contained anadromous herring, and we used bioenergetics modeling to evaluate the importance of herring prey to largemouth bass growth. During May through November 1994, largemouth bass diets consisted of various fish species, crayfish, and other invertebrates. Although not the most important prey overall, herring were the most important fish prey consumed in both lakes based on number of individuals consumed. I...

Opinion: Endogenizing culture in sustainability science research and policy

Integrating the analysis of natural and social systems to achieve sustainability has been an international scientific goal for years (1, 2). However, full integration has proven challenging, especially in regard to the role of culture (3), which is often missing from the complex sustainability equation. To enact policies and practices that can achieve sustainability, researchers and policymakers must do a better job of accounting for culture, difficult though this task may be.

Problem-solving Research for Management: A Perspective

Abstract We convened a symposium titled “Problem-solving Research for Management: Shared Responsibilities” at the 123rd annual meeting of the American Fisheries Society in Portland, Oregon. Our symposium sought to encourage researchers and managers to work together more effectively by reviewing successful research projects that have incorporated problem-solving approaches. In this first paper, we carefully define and distinguish between management and research by exploring the goals and tools of each discipline. In our view, problem-solving for management, as an iterative approach of which research is a major component, serves as a template for improving the relationship between managers and researchers as well as contributing to the solution of management problems. To improve the less-than-stellar record of interaction between these two groups, not only must problem-solving approaches be incorporated into the effort, but managers and researchers also must come to recognize, appreciate, and understand the...

Seasonal use of a New England estuary by foraging contingents of migratory striped bass

Abstract Using acoustic telemetry on migratory striped bass Morone saxatilis in Plum Island Estuary (PIE), Massachusetts, we found that striped bass (335–634 mm total length) tagged in the spring and summer of 2005 (n = 14) and 2006 (n = 46) stayed in the estuary for an average of 66.0 d in 2005 and 72.2 d in 2006. Striped bass spent the most time in two specific reaches: middle Plum Island Sound and lower Rowley River. In both years, three different use-groups of striped bass were observed in PIE. Short-term visitors (n = 24) stayed in the estuary only briefly (range = 5–20 d). Two groups of seasonal residents stayed for more than 30 d, either in the Rowley River (n = 14) or in Plum Island Sound (n = 22). Within PIE, the two seasonal-resident use-groups may be foraging contingents that learn how to feed efficiently in specific parts of the estuary. These distinct within-estuary use patterns could have different implications for striped bass condition and prey impact.

How Big of an Effect Do Small Dams Have? Using Geomorphological Footprints to Quantify Spatial Impact of Low-Head Dams and Identify Patterns of Across-Dam Variation

Longitudinal connectivity is a fundamental characteristic of rivers that can be disrupted by natural and anthropogenic processes. Dams are significant disruptions to streams. Over 2,000,000 low-head dams (<7.6 m high) fragment United States rivers. Despite potential adverse impacts of these ubiquitous disturbances, the spatial impacts of low-head dams on geomorphology and ecology are largely untested. Progress for research and conservation is impaired by not knowing the magnitude of low-head dam impacts. Based on the geomorphic literature, we refined a methodology that allowed us to quantify the spatial extent of low-head dam impacts (herein dam footprint), assessed variation in dam footprints across low-head dams within a river network, and identified select aspects of the context of this variation. Wetted width, depth, and substrate size distributions upstream and downstream of six low-head dams within the Upper Neosho River, Kansas, United States of America were measured. Total dam footprints averaged 7.9 km (3.0–15.3 km) or 287 wetted widths (136–437 wetted widths). Estimates included both upstream (mean: 6.7 km or 243 wetted widths) and downstream footprints (mean: 1.2 km or 44 wetted widths). Altogether the six low-head dams impacted 47.3 km (about 17%) of the mainstem in the river network. Despite differences in age, size, location, and primary function, the sizes of geomorphic footprints of individual low-head dams in the Upper Neosho river network were relatively similar. The number of upstream dams and distance to upstream dams, but not dam height, affected the spatial extent of dam footprints. In summary, ubiquitous low-head dams individually and cumulatively altered lotic ecosystems. Both characteristics of individual dams and the context of neighboring dams affected low-head dam impacts within the river network. For these reasons, low-head dams require a different, more integrative, approach for research and management than the individualistic approach that has been applied to larger dams.

Processes Contributing to Variability in Regional Patterns of Juvenile River Herring Abundance across Small Coastal Systems

Abstract Many populations of anadromous herring, (e.g., alewives Alosa pseudoharengus and blueback herring A. aestivalis, collectively referred to as river herring) are in decline. To help understand the various processes influencing their relative abundance, we studied juvenile river herring populations in 11 small, coastal Massachusetts systems. We examined diel and seasonal movements, variation in patterns of abundance, and relationships between juvenile river herring numbers and seven abiotic and biotic factors (stream discharge, pond temperature, habitat availability, pond transparency, pH, food availability, and spawning stock size). Seasonally, juvenile downstream migration peaked in early summer, and most juvenile river herring emigrated between 1200 and 1600 hours. Little or no emigration occurred in late summer when stream channels were often dewatered, although several streams experienced a smaller, more variable emigration peak in the fall. In univariate regressions, stream discharge, pond vol...

Evaluation of a Gastric Radio Tag Insertion Technique for Anadromous River Herring

Abstract Anadromous river herring (alewives Alosa pseudoharengus and blueback herring A. aestivalis), which constitute a historically and ecologically important component of coastal rivers, have declined precipitously throughout the Atlantic seaboard. Suggested causes of river herring decline include commercial fishing and predation by striped bass Morone saxatilis. Although the causes of this recent trend are poorly understood, river herring are especially vulnerable to adverse impacts during their spring spawning migration. Radiotelemetry is an especially useful method for addressing potential problems encountered during the movement of these fish from the ocean to freshwater. In spite of frequent calls for evaluation of telemetry methods, controlled tests of posttagging effects are rare for alosids and virtually nonexistent for anadromous river herring. We developed a protocol for gastric tagging of anadromous river herring, and we used hatchery and field studies to evaluate behavior, tag placement, st...

A Biosocial Approach for Analyzing Environmental Conflicts: A Case Study of Horseshoe Crab Allocation

Abstract Ambiguous legislation, insufficient science, jurisdictional disputes, and conflicting values of stakeholders have contributed to the increasing frequency of natural resource conflicts. The allocation of horseshoe crabs in Delaware Bay and Cape Cod Bay can serve as a model system for understanding resource conflicts, because relationships among biophysical and human systems in this example typify many environmental controversies. Herein, we use an interaction web to build a conceptual framework for identifying potential conflicts. Specifically, we identify four subconflicts involving horseshoe crabs, human shellfishers, commercial fishers, the biomedical industry, birdwatchers, and environmental interest groups. Stakeholders hold different attitudes concerning the horseshoe crab and thus advocate competing policy preferences in the political process. An important step in understanding environmental conflicts is to clarify differences in social meanings, attitudes, and values. The integrated approach described here, by depicting and graphically displaying biosocial relationships, can provide a generalized approach for understanding a broad range of environmental conflicts.

Are We Preparing the Next Generation of Fisheries Professionals to Succeed in their Careers?: A Survey of AFS Members

Natural resource professionals have frequently criticized universities for poorly preparing graduates to succeed in their jobs. We surveyed members of the American Fisheries Society to determine which job skills and knowledge of academic topics employers, students, and university faculty members deemed most important to early-career success of fisheries professionals. Respondents also rated proficiency of recently hired, entry-level professionals (employers) on how well their programs prepared them for career success (students and faculty) in those same job skills and academic topics. Critical thinking and written and oral communication skills topped the list of important skills and academic topics. Employers perceived recent entry-level hires to be less well-prepared to succeed in their careers than either university faculty or students. Entry-level hires with post-graduate degrees rated higher in proficiency for highly important skills and knowledge than those with bachelors degrees. We conclude that a...