Skates possess weak electric organs that bear some similarities to the more infamous organs of electric eels and stingrays, and even more similarity to weakly electric gymnotiform and mormyrid freshwater fishes. Skates and other weakly electric fishes differ from those with powerful electric organs in that the discharges emitted from their organs are too weak to act as a predatory tool or defense mechanism. This insight generates curiosity as to what the function of an electric organ might be if not to defend against predator or obtain prey. Weakly electric gymnotiform and mormyrid fishes have received a large majority of research attention to address this consideration. As a result, much is known about the electric organ and electric organ discharge (EOD) of gymnotiform and mormyrid fishes, including their accepted use in electrolocation and electrical communication. One can speculate as to why elasmobranchs are historically understudied in comparison to teleost fishes. However, research that has been conducted over the years on weakly electric teleosts to elucidate the function of their organs lends itself as an example for future research that aims to identify the function of the similarly weak electric organ of skates.
This thesis is separated into two chapters. The first is a review that aims to identify areas of potential research interests into determining the role of the skate electric organ. It presents brief summaries of what is known about the weak electric organs of teleosts and compares this information with what little is known about skate electric organs. The most probable function for the skate electric organ is electrical communication, therefore this is the focus of the review. The majority of attention is devoted to skates, whereas teleost research is presented more as an example for future skate research.
The second chapter is a morphological study on the electric organ of one skate species in an attempt to identify ontogenetic or gender differences in the organ as a whole or in the individual electrocytes that make up the organ. Justification for this study stems from the areas of needed research identified in Chapter 1. In other words, characterizing morphological differences by gender and maturity status for the skate electric organ is one of many labors required to elucidate its function. The results of this study are discussed in terms of the evidence they provide toward a communication function for the skate electric organ.
|Commitee:||Burke, Russell, Williams, Jason|
|School Location:||United States -- New York|
|Source:||MAI 46/06M, Masters Abstracts International|
|Subjects:||Ecology, Anatomy & physiology, Animals|
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