Geology topics

Joseph Kozfkay

Publications and source records attributed to Joseph Kozfkay.

3 recordsLinked to original sources

USGS2025

Why the whole is greater than the sum of its parts: A case for population-level management

Catch-and-release regulations in recreational fisheries have been implemented for decades with the intention of allowing fishing while reducing fishing mortality. In addition, voluntary catch-and-release behaviors are increasingly common. Social and scientific interest in fish handling practices in catch-and-release fisheries as they relate to stress, reflex impairment, reproductive success, and mortality has been expanding. The scientific literature is now replete with studies that examine these issues, and they have become a fixture in the public discourse on angling. Scientists and anglers are making fishing regulation proposals and suggestions for fish-handling practices. The proximal intent of these recommendations is to reduce excessive stress or mortality on a per capita basis with a belief that the reduction ultimately has a positive effect on the population. Whether the proximal intent achieves population goals depends on several factors, including effort, population dynamic rates, and stock-recruitment dynamics. This perspective reviews the state of the science relative to a hierarchical framework of fishery population dynamics, with a call for fishery scientists to consider their scope of inference and assumptions relative to conservation and population management.

Article↗

USGS2025

Points of consensus on catch-and-release: Considerations for science, ethics, and fisheries management

Catch-and-release (C&R), whether via regulations or voluntary actions, is typically employed with the intent of reducing fishing mortality while maintaining recreational angling opportunities (Isermann & Paukert, 2010), but there has been significant discourse about the relative importance of individual-level (see Cooke et al., 2025) vs. population-level (see Corsi et al., 2025) effects of C&R. We hope to offer the angling, scientific, and management communities some points of consensus from which this multifaceted dialogue on C&R can productively build. We preface this by noting that our collective views were informed by this process and the opportunity to share and learn from each other. What is apparent from this exercise is the value of embracing a holistic, cooperative approach. From a regulatory perspective, C&R is typically implemented in high-effort fisheries that are popular due to the quality of the fishing. Catch-and-release regulations are also applied in fisheries where populations have declined and fishing mortality is thought or, most appropriately, known to be a limiting factor for the population. When practiced voluntarily, anglers engaging in C&R can be characterized by high avidity and specialization, and angling is often a central component of their identity (e.g., Fisher, 1997). Due to their passion, avid anglers tend to spotlight the ethical, scientific, and regulatory considerations of C&R. As such, there is a need in fisheries management and science to understand in what situations these considerations transcend biological scales and how to navigate the gamut of voluntary actions and regulatory mandates. In this essay, we offer a distillation of the emergent consensus concepts that we hope managers and researchers will consider at both individual and population scales for legal, ethical, and scientific deliberations.

Fisheries↗

USGS2019

Movement dynamics of Smallmouth Bass in a large western river system

The Snake River, Idaho, between Swan Falls and Brownlee dams supports a popular fishery for Smallmouth Bass Micropterus dolomieu . Recently, anglers have expressed concern about harvest of Smallmouth Bass associated with seasonal congregations in and near the lower reaches of several major tributaries. Little is known about Smallmouth Bass movement in the system, and a better understanding of movement dynamics will help to guide future management. From March to August 2016, Smallmouth Bass (≥260 mm; n = 1,131) were tagged with T-bar anchor tags to evaluate large-scale movement patterns. Movement was estimated from 63 angler-reported tags for which area descriptions provided sufficient detail to assign a recapture location. Extent of fish movement varied among segments and tributaries from 0 to 128 river kilometers (rkm). From March to May 2017, Smallmouth Bass (≥305 mm; n = 149) in the Snake, Boise, Payette, and Weiser rivers and in Brownlee Reservoir were implanted with radio transmitters. Of the 149 Smallmouth Bass that were released with radio transmitters, 107 were relocated at least once. Additionally, 79.6% of fish with radio transmitters had a maximum extent of movement of 5 rkm or greater and 42.6% had a maximum extent of 30 rkm or greater; one radio-tagged fish moved 167 rkm upstream. Average daily movement of Smallmouth Bass varied among river segments and was greatest in the spring and summer. Fish from the Snake River, tributaries (e.g., Boise River), and Brownlee Reservoir moved all around the study area, indicating an absence of clear population boundaries. As such, Smallmouth Bass in the study area appear to function as one large population as opposed to multiple subpopulations, thereby indicating that management as one population is likely appropriate.

Idaho↗