Examining the Density Gradient Along the Rhizophora mangle Propagule

Marissa Mohn — 2026-09-25

Mangroves grow in tropical regions around the globe, but these dense forests have been declining due to agriculture, industry, and climate change. While of great ecological and economic importance, mangrove restoration is costly and has high failure rates. More research is needed to determine how these plants function. Mangrove propagules are not seeds but the seedlings themselves that grow on the parent tree until they reach maturity and fall. They are water dispersed, floating horizontally in seawater and vertically in brackish water. This study investigated the change in density longitudinally along the Rhizophora mangle propagule. Propagules were cut into one-centimeter sections and the density of each section calculated. The data shows that the density of the propagules increases from the plumule end to the radicle end until around 80-90% of the length of the propagule, at which point the density decreases. This density gradient is consistent with a propagule floating vertically with the radicle end below the plumule end. A cross-section of the propagule shows an inner medulla surrounded by a cortex. Towards the radicle end of the propagule, the cortex sinks while the medulla continues to float.

Paddlefish Movement and Dam Passage in the Ohio and Kanawha Rivers Depend on River Conditions

Stuart Welsh — 2026-11-01

The population of Paddlefish (Polyodon spathula) has increased in the Ohio River drainage of Ohio and West Virginia due to stocking efforts of the past few decades. However, Paddlefish movement was minimally investigated in this region of their range. In fall 2022, five Paddlefish were captured and tagged with acoustic transmitters. Their movements through the Ohio River and several tributaries were monitored from April 2023 to July 2025. Paddlefish moved most in the spring and were largely stationary until water temperatures reached at least nine °C. Using logistic regression, we determined that Paddlefish movement varied in relation to water temperature, gage height, and temperature change from the previous day. Peak probability of movement occurred during water temperatures around 21.9 °C, high gage height, and rising water temperatures (i.e., springtime high water events). Paddlefish directional movement probability depended on gage height, with the highest probability of upstream movement occurring at a gage height 8.9 ft higher than the median gage height. Sixty total lock and dam passage attempts were recorded with seven successful upstream and three successful downstream passages. Paddlefish generally attempted upstream passages during colder water and higher gage heights when compared to downstream passage attempts. Findings from this study could inform managers about Paddlefish movements in the region and inform potential conservation lockage timing

Proceedings of the West Virginia Academy of Science

Examining the Density Gradient Along the Rhizophora mangle Propagule

Paddlefish Movement and Dam Passage in the Ohio and Kanawha Rivers Depend on River Conditions