GARssections!

WARNING: GRAPHIC (but educational) – A throwback to our research on Spotted Gar (Lepisosteus oculatus) ecology in 2011, here’s an impromptu video on sex determination of the species.

In order to better understand species’ population and life history characteristics (and inform conservation and management), we need to know its size and age structure, as well as variation of that structure between males and females. In general, the sex of gars cannot be determined externally, therefore a population sample is dissected for internal examination. We used other structures of the fish (otoliths, rays, bones, etc) for additional analyses.

references:
Ferrara & Irwin 2001
A Standardized Procedure for Internal Sex Identification in Lepisosteidae
http://bit.ly/1AhB4Et

David 2012
Life history, growth, and genetic diversity of the spotted gar (Lepisosteus oculatus) from peripheral and core populations
http://bit.ly/1DdgomL

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First Gar-Spotting in the Second City

Illinois Department of Natural Resources biologist Frank Jakubicek holds up the Spotted Gar (Lepisosteus oculatus) specimen found in the North Branch Channel of the Chicago River in September 2014

Illinois Department of Natural Resources (IDNR) biologist Frank Jakubicek holds up the Spotted Gar (Lepisosteus oculatus) specimen found in the North Branch Channel of the Chicago River in September 2014. Photo by IDNR (used with permission).

Earlier this fall (September 2014) during a routine survey on the lookout for Asian carp (Bighead and Silver Carps), Illinois Department of Natural Resources fisheries biologists instead found a Spotted Gar (Lepisosteus oculatus) in the North Branch Channel of the Chicago River. This marked the first finding of the species in the Chicago Area Waterways System (CAWS), and northwestern-most occurrence of the species in Illinois (and the Great Lakes region).

As you can imagine, we were quite excited to get involved and expound upon the implications of this find! In preparation for an upcoming more detailed commentary and new entries (finally!), we are posting some links to the media accounts of the find, as well as the National Geographic blog by Primitive Fishes author Solomon David. More to come!

DNAinfo Chicago:
Spotted Gar Discovered for the First Time in Chicago Waters

Chicago Tribune:
Primitive fish found for first time in Chicago waterway

Chicago Sun-Times:
Could lone spotted gar be a harbinger of clearer water?
Voices | More spotted gar info

CBS Chicago WBBM Radio:
Biologists Find Spotted Gar for First Time in Chicago Area Waterways

National Geographic Newswatch:
Gar Spotted in the Windy City: First Occurrence of the Primitive Fish

Longnose Gar (Lepisosteus osseus)

Longnose Gar (Lepisosteus osseus)

Here’s a quick shot of one of the gar specimens we donated to Shedd Aquarium; this specimen is on exhibit (along with a Shortnose Gar Lepisosteus platostomus) in the recently renovated “At Home on the Great Lakes” Gallery!