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Terminal lakes are lakes with no hydrologic surface outflows and with losses of water occurring only through surface evaporation and groundwater discharge. We quantified the extent of the littoral zones (areas where 1% or more of surface irradiation reaches the lake bottom) and open water zones (areas where less than 1% of surface irradiation reaches the lake bottom) in 18 terminal lakes. Additionally, we quantified habitat usage and diets of the fish species inhabiting these lakes. This dataset contains includes seven lakes in North America (Atitlan, Crater, Eagle, Mann, Pyramid, Summit, Walker), one in South America (Titicaca), five in Eurasia (Caspian, Issyk-Kul, Neusiedl, Qinghai, Van), and five in Africa (Abijatta, Manyara, Nakuru, Shala, Turkana).

Description of the data and file structure

All of the data pertaining to fish habitat and diet is contained in All_Lakes_Fish_Data.csv. This dataset contains a unique record for each fish species in each lake. This file contains fields for a) the continent on which the lake is located; b) the species' scientific name; c) the taxonomic family to which the species belongs; d) the taxonomic order to which the species belongs; e) the species' habitat; f) the species' diet; g) the status of the species in the lake as either an endemic taxa, a native taxa, or a non-native taxa; h) the surface area of the lake (in square kilometers); i) the depth of the lake (in meters); j) the 1% PAR depth (in meters); k) the percent of the lake's surface area overlying littoral habitat; l) the surface area of the lake's littoral zone (in square kilometers); m) the references consulted in quantifying the taxa's habitat use; and n) the references consulted in quantifying the taxa's diet.

There are GIS files for each lake's shoreline, open water zone, littoral zone, and interpolated bathymetry. The interpolated bathymetry is in raster format, while the open water zones, littoral zones, and shorelines are in shapefile formats. These are stored in compressed folders named in accordance with the following formula: Lakename_year_Datatype.zip

Examples:

1. The shapefile for Pyramid Lake's 1970 shoreline is named Pyramid_1970_Shoreline.zip
2. The raster file for Crater Lake's 2020 bathymetry is named Crater_2020_Bathymetry.zip
3. The shapefile for Mann Lake's 2020 open water zone is named Mann_2020_Open_water_zone.zip
4. The shapefile for Mann Lake's 2020 littoral zone is named Mann_2020_Littoral_zone.zip

The following offers specific details for each lake's GIS files:

Abijatta:

The 1% PAR depth is 1.62 meters (Belay & Wood 1984). The bathymetry was generated by digitizing the contours published in Legesse et al. 2004 and then interpolating into a raster using the Natural Neighbor function. Changes in size from 1980 to 1995 were calculated from water depth reported by Legesse 2004.

Atitlan:

Bathymetric contours provided by Domingo Francisco Ujpan. 1% PAR depth is 27.5 meters. This is calculated by 2.5 x Secchi depth. Secchi depth is 11 meters in the center of the lake (Rejmankova et al. 2011).

Caspian:

A 1% light level of 11.5 meters (calculated from a Secchi disk depth of 4.6 meters reported in Bagheri et al. 2012) was used to delineate the boundary between the open water and littoral zones. A Bathymetry DEM published by GEBCO was used to generate the bathymetry of the Caspian Sea.

Crater:

Bathymetry of Crater Lake available at: http://oe.oregonexplorer.info/craterlake/bathymetry.html#download
The 1% light depth is 86 meters, courtesy of data provided by Scott Girdner.

Eagle:

Secchi depth measurements were provided by Ryan McKim that were recorded in the southern basin in the 2000s. The average of these Secchi depths was 17.3 feet. Therefore, the 1% PAR depth was approximated as 17.3 feet x 2.5 = 43 feet = 13.1 meters. The bathymetry raster was generated by digitizing contours from Vail et al. 1974 and then interpolating a raster using the natural neighbor method.

Issyk-Kul:

Light attenuation is reported by Abakumov 2019: 0.045/meter. Bathymetry was provided in raster format by Damien Delvaux. The raster file integrates the bathymetry of the lake with the surrounding topography. Raster calculator was used to remove all elevations greater than the surface elevation (1607 meters).

Mann:

Bathymetry from 1959 (Atlas of Oregon Lakes) was used to generate contours of the lakes depth. Then, a raster was interpolated from the contours. This raster was then clipped to a polygon drawn of the 2020 shoreline from Landsat imagery. The 1% light depth is the 2007 Secchi depth (0.48m) x 2.5 = 1.2 meters (Atlas of Oregon Lakes).

Manyara:

A 1% PAR depth was calculated from the minimum and maximum Secchi values reported in Kiwhele et al. 2015. A minimum value of 2.5 cm was recorded in March, and a maximum value of 19.5 cm was recorded in May. Therefore, 1% PAR depth was 0.275 meters. The bathymetry raster was generated from interpolation of contours digitized from Deus et al. 2013.

Nakuru:

1% PAR depth is 0.91 meters (Vareschi 1982). Bathymetry was generated by digitizing contours shown in Vareschi 1982.

Neusiedl:

Somogyi et al. 2010 reports a Secchi depth maximum of 30 cm. Therefore, 1% PAR depth is 0.3 x 2.5 = 0.75 meters. The extent of the reed zone was digitized from georeferenced images from Krachler et al. 2009. The reed zone was considered inherently littoral. A bathymetry raster was generated from sonar measurements provided by Tamas Kramer.

Pyramid:

The 1% PAR depth used to distinguish littoral and open water zones is 11 meters according to unpublished data from 1976 & 1977 collected by the Pyramid Lake Paiute Tribe. Contours were digitized from Harris 1970.

Qinghai:

Bathymetric contours from 2004 were provided as a shapefile by Quangyin Hu. A raster DEM was generated from these contours. The boundary between pelagic and open water zones were determined from Secchi disk readings reported in Ao et al. 2014:
June Secchi = 3.2 meters
August Secchi = 2.94
Mean = 3.07 meters
3.07 X 2.5 = 7.7 1% light depth

Shala:

Bathymetry raster was generated by digitizing the contours presented in Baumann et al. 1975. The 1% PAR depth is 4.93 meters (Belay & Wood 1984).

Summit:

A Secchi depth of 2.4 meters is reported in Barnes et al. 2015. This was used to calculate a 1% PAR depth of 2.4*2.5 = 6 meters. Bathymetric contours reported in Barnes et al. 2015 were digitized and interpolation was used to generate a bathymetric raster.

Titicaca:

In the northern basin, the Secchi depths are 11.8, 11.9, 13.2, 12.4, and 13.9 meters. The average of this multiplied by 2.5 is 32 meters which is an approximation of the 1% PAR depth for the northern basin. In the southern basin, the Secchi depths are 4.7, 4.5, 5.6, 5.4, and 3.2 meters. The mean of this multiplied by 2.5 is 12 meters which is an approximation of the 1% PAR depth for the southern basin (Iltis et al. 1992). The bathymetry was provided as a raster by Sheri Briggs from University of Nebraska, Lincoln.

Turkana:

A mean 1% PAR depth of 6 meters was used to delineate littoral and open water zones (Kallqvist et al. 1988). Bathymetry raster was generated by contours reported in Kallqvist et al. 1988.

Van:

A 1% PAR depth was calculated from Secchi depth values reported in Ozguven & Yetis 2020 which reported a dry season Secchi of 2.54 meters and a wet season Secchi of 3.21 meters. Therefore, the mean Secchi depth is 2.875, and 1% PAR depth is 7.18 meters. Contours were digitized from Huguet et al. 2012. These contours were then interpolated to create a raster.

Walker:

LANDSAT 5 images from 1984 and 2014 were used to generate polygons of the shorelines in 1984 and 2014. A bathymetry DEM was used from Smith & Lopes 2007. The DEM from Smith & Lopes 2007 was clipped to the polygons generated of the lake shoreline for 1984 and 2014. A 1% PAR depth of 17 meters was calculated from the mean of the 1% PAR values reported in Figure A.4.8 in Collopy & Thomas 2010.

Literature Cited:

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