Date Available

10-19-2019

Year of Publication

2018

Degree Name

Master of Science (MS)

Document Type

Master's Thesis

College

Arts and Sciences

Department/School/Program

Earth and Environmental Sciences (Geology)

First Advisor

Dr. Michael McGlue

Abstract

Small scale protected zones are valuable for helping the health and productivity of fisheries at Lake Tanganyika (East Africa). Spatial placement of protected areas relies on accurate maps of benthic habitats, consisting of detailed bathymetry data and information on lake-floor substrates. This information is unknown for most of Lake Tanganyika. Fish diversity is known to correlate with rocky substrates in ≤ 30 m water depth, which provide spawning grounds for littoral and pelagic species. These benthic habitats form important targets for protected areas, if they can be precisely located.

At the NMVA, echosounding defined the position of the 30-m isobath and side-scan sonar successfully discriminated among crystalline basement, CaCO3-cemented sandstones, mixed sediment, and shell bed substrates. Total area encompassed from the shoreline to 30 m water depth is ~21 km2 and the distance to the 30-m isobath varies with proximity to deltas and rift-related faults. Total benthic area defined by crystalline basement is ~1.6 km2, whereas the total area of CaCO3-cemented sandstone is 0.2 km2. Crystalline basement was present in all water depths (0-30 m), whereas CaCO3-cemented sandstones were usually encountered in water ≤ 5 m deep. Spatial organization of rocky substrates is chiefly controlled by basin structure and lake level history.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2018.392

Funding Information

This research was funded by the Society of Exploration Geophysicists Geoscientists Without Borders Program (Award #201401005 to MM) and supplemented by small grants from the University of Kentucky to JL.

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