Geology topics

Jeffrey C. Jolley

Publications and source records attributed to Jeffrey C. Jolley.

4 recordsLinked to original sources

USGS2026

Validation of daily age in Grass Carp reared in tanks and outdoor ponds in the U.S. Midwest

Objective Accurate and precise age estimation is essential for understanding early life history, recruitment, and population dynamics in fish. However, daily otolith increment deposition has not been validated for Grass Carp Ctenopharyngodon idella in the Midwestern United States. Our objective was to validate daily increment deposition in lapilli otoliths of known-age Grass Carp that were reared under controlled laboratory and outdoor pond environments and to evaluate the reliability of otolith-based daily age estimation across early life stages. Methods Larval Grass Carp that were hatched from captive broodstock were reared in indoor tanks and outdoor ponds and sampled between 6 and 120 d posthatch. The lapilli otoliths were extracted, lightly sanded, and independently read three times to estimate age. The estimated ages were compared with known chronological age to assess the accuracy and precision of daily increment counts across rearing environments. Results Daily increment deposition was validated through 51 d posthatch for the tank-reared fish and through 69 d posthatch for the pond-reared fish. Beyond these ages, the estimated ages increasingly underestimated known age due to compression of daily increments near the otolith core and outer margin, particularly in slower growing individuals. Growth rates differed substantially between the two rearing environments and influenced increment spacing and readability. Otolith size was strongly correlated with the total length of the fish but decreased relative to chronological age as increment compression increased, particularly in fish exceeding approximately 40–50 mm total length (TL) in tank-reared and 60–70 mm TL in pond-reared individuals. Conclusions Lapilli otoliths provide reliable daily age estimates for Grass Carp during early life stages under both laboratory and pond conditions. These validated methods enable robust estimation of hatch timing and early growth, providing a foundational tool for studying early life history and informing control efforts for invasive Grass Carp populations

Missouri↗

USGS2018

Tag retention and survival of juvenile bighead carp implanted with a dummy acoustic tag at three temperatures

Bighead carp Hypophthalmichthys nobilis and silver carp Hypophthalmichthys molitrix (together, the bigheaded carps) are invasive fishes in North America that have resulted in substantial negative effects on native fish communities and aquatic ecosystems. Movement and behavior of adult bigheaded carps has been studied previously using telemetry, while similar studies with juvenile bigheaded carps have yet to be attempted. Recent technological advances in telemetry transmitters has increased the availability of tags sufficiently small enough to implant in juvenile carps. However, the effects of surgical implantation of telemetry tags on juvenile bigheaded carps have not been evaluated. We determined tag retention and survival associated with surgical implantation of acoustic telemetry tags into juvenile bighead carp (range 128–152 mm total length) at three temperatures (13, 18, and 23°C). In addition, we assessed the effect of surgically implanted transmitters on the fitness, defined as changes in weight or critical swimming speed, of carp implanted with transmitters. Survival was high among tagged fish (85%) with 47% of tags retained at the conclusion of the 45‐day study. No substantial decline in fitness of the fish was observed in tagged fish compared to untagged fish.

Journal of Applied Ichthyology↗

USGS2017

Conservation challenges and research needs for Pacific lamprey in the Columbia River Basin

The Pacific Lamprey Entosphenus tridentatus , an anadromous fish native to the northern Pacific Ocean and bordering freshwater habitats, has recently experienced steep declines in abundance and range contractions along the West Coast of North America. During the early 1990s, Native American tribes recognized the declining numbers of lamprey and championed their importance. In 2012, 26 entities signed a conservation agreement to coordinate and implement restoration and research for Pacific Lamprey. Regional plans have identified numerous threats, monitoring needs, and strategies to conserve and restore Pacific Lamprey during their freshwater life stages. Prime among these are needs to improve lamprey passage, restore freshwater habitats, educate stakeholders, and implement lamprey-specific research and management protocols. Key unknowns include range-wide trends in status, population dynamics, population delineation, limiting factors, and marine influences. We synthesize these key unknowns, with a focus on the freshwater life stages of lamprey in the Columbia River basin.

British Columbia, Idaho, Montana, Nevada, Oregon, ↗

USGS2016

Common carp disrupt ecosystem structure and function through middle-out effects

Middle-out effects or a combination of top-down and bottom-up processes create many theoretical and empirical challenges in the realm of trophic ecology. We propose using specific autecology or species trait (i.e. behavioural) information to help explain and understand trophic dynamics that may involve complicated and non-unidirectional trophic interactions. The common carp ( Cyprinus carpio ) served as our model species for whole-lake observational and experimental studies; four trophic levels were measured to assess common carp-mediated middle-out effects across multiple lakes. We hypothesised that common carp could influence aquatic ecosystems through multiple pathways (i.e. abiotic and biotic foraging, early life feeding, nutrient). Both studies revealed most trophic levels were affected by common carp, highlighting strong middle-out effects likely caused by common carp foraging activities and abiotic influence (i.e. sediment resuspension). The loss of water transparency, submersed vegetation and a shift in zooplankton dynamics were the strongest effects. Trophic levels furthest from direct pathway effects were also affected (fish life history traits). The present study demonstrates that common carp can exert substantial effects on ecosystem structure and function. Species capable of middle-out effects can greatly modify communities through a variety of available pathways and are not confined to traditional top-down or bottom-up processes.

Marine and Freshwater Research↗