Geology topics

Kyle T. Morton

Publications and source records attributed to Kyle T. Morton.

4 recordsLinked to original sources

USGS2025

Unique thermal mixing patterns in Lake Ontario revealed by novel year-round observations of thermal stratification

Year-round records of thermal stratification in the Great Lakes are rare, and there are few observations of thermal stratification during winter. In this paper, we analyze temperature data from 13 temperature logger chains and from over 130 benthic acoustic receivers that were deployed across Lake Ontario for 2 yr. The timing and duration of the fall overturn correlate with the local average water depth, and shallow sites (< 50 m depth) overturn up to a month before deep sites (> 100 m depths). Likewise, in spring, the shallow sites warm faster. Lake Ontario has partial ice cover, so wind-driven mixing stirs the water column throughout winter, and inverse thermal stratification is largely absent. The depth-averaged winter water temperatures vary between 0°C and 4°C, with the coldest temperatures (near 0.1°C) found in the shallow Kingston basin and warmest temperatures (near 4°C) at sites near the 244 m deep Rochester Basin. Lake Ontario appears to be a warm monomictic lake, rather than having a dimictic mixing pattern as previously described—there is no sustained ice cover or inverse stratification that inhibits vertical mixing in winter. Winter is a poorly understood season for many aquatic processes, including fish bioenergetics, fish distribution, biochemical processes, invertebrate distribution, and production. Moreover, the lack of knowledge of winter has hampered the use of correct initial conditions for running large lake hydrodynamic models.

Lake Ontario↗

USGS2025

Movement characterizations of stocked juvenile lake sturgeon (Acipenser fulvescens) within the Genesee River, NY

Knowledge of the movements of post-stocked juvenile lake sturgeon ( Acipenser fulvescens ) within and beyond the Genesee River of New York is limited. Describing lake sturgeon post-stocking movements could further the understanding of population structure and the delineation of nursery habitat. This project aimed to characterize the movements of juvenile sturgeon by tagging and tracking 69 age-0 + and 30 sub-adult lake sturgeon with acoustic transmitters from 2019 to 2021. Habitat use was disproportionate between the two life stages of juvenile sturgeon; age-0 + lake sturgeon primarily inhabited the upper reaches of the Genesee River, while sub-adults primarily utilized the lower dredged reaches of the Genesee River and the embayment outside of the river. A lower proportion of age-0 + lake sturgeon left the Genesee River relative to sub-adults, with seven sub-adult sturgeon (23.3 % of all tagged) moving to new habitats over 100 km away. Water temperature, discharge, and dissolved oxygen concentrations best predicted lake sturgeon movement within the river. These results indicate that the Genesee River is serving as a nursery habitat for juvenile lake sturgeon and that connectivity exists among the river, nearshore Lake Ontario habitats, and other tributaries. Such information is important when considering that management efforts for this species are commonly uniform across a system, while our results suggest a broader metapopulation framework may be relevant.

New York↗

USGS2025

Factors affecting short-term post-release survival probability of Lake Trout implanted with acoustic telemetry transmitters

The use of acoustic telemetry is steadily expanding to help answer questions related to habitat use, movement, and behavior of fishes. Significant time and resources are invested to start acoustic telemetry studies; therefore, careful planning is needed to limit post-release mortality of tagged individuals. Deep, cold-water species present additional challenges to acoustic tagging because of changes in temperature and pressure experienced during capture. The objective of our study was to determine if capture method, surface water temperature, water depth, or fish size influenced short-term post-release survival of a deep, cold-water species, Lake Trout Salvelinus namaycush . In 2023, 299 Lake Trout were captured with angling or gillnets across Lake Ontario (Laurentian Great Lake – U.S. & CAN) and surgically implanted with acoustic transmitters. We estimated 30-day post-release mortality and 24-h post-release distance traveled for tagged Lake Trout. We used Cox proportional hazards models to identify factors affecting survival probability and multiple linear regression to identify factors affecting post-release distance traveled. Thirty-day post-release mortality was minimal (9.03 %, 27/299 Lake Trout); however, mortality was 6.37 times more likely for Lake Trout captured in gillnets compare to angling ( p = 0.003). Lake Trout length had a marginally significant effect on mortality ( p = 0.052) but capture depth and temperature did not ( p > 0.05). Lake Trout post-release distance traveled was not significantly influenced by capture gear, depth, temperature, or Lake Trout length ( p = 0.61). Our results indicate that tagging-induced post-release mortality is minimal for Lake Trout tagged in the spring, but survival can be increased by avoiding use of gillnets.

Lake Ontario↗

USGS2025

Emigration probabilities and survival estimates of stocked juvenile lake sturgeon (Acipenser fulvescens) within the Genesee River, NY

Knowledge of juvenile lake sturgeon ( Acipenser fulvescens ) survival is important both to understanding changes in population abundance and for assessing the efficacy of management practices like stocking. High mortality rates of juvenile fish are partially mitigated by stocking hatchery-raised individuals; however, survival of post-stocked lake sturgeon remains lower compared to survival at older life stages. In this study, acoustic telemetry data from 69 age-0+ (weight: = 29 g, range = 2–41 g; length: = 198 mm, range = 176–223 mm) and 30 sub-adults (weight: = 2144 g, range = 1100–7020 g; length: = 751 mm, range = 605–1020 mm) tagged in the fall of 2019 and 2020 were utilized to construct a multi-state model used to estimate both survival and spatial transitions between the Genesee River and Lake Ontario. Sub-adults (approximate ages: 4–7 years) had estimated survival rates exceeding 88 % in both the Genesee River and Lake Ontario. Age-0+ lake sturgeon displayed much lower survival rates that ranged between 31 % (Lake Ontario) and 77 % (Genesee River). Both age-0+ and sub-adults lake sturgeon were most likely to leave the Genesee River in the fall and winter months, while being most likely to return in the spring and summer months. The approach used in this study to estimate survival is hypothesized to have led to higher survival estimates than traditional Capture-Mark-Recapture (CMR) derived estimates as a result of accounting for emigration from the Genesee River.

New York↗