I confess that I have been lazy in pursuing this shark example. I didn't go right away and read the primary literature to which TSRM referred. I still have not gotten to the (Kalmijn, 1974) to which TSRM refer, but I did the lazy thing and downloaded what I could from the internet, namely, (Kalmijn, 1971). It is available here. Their Figure 2 seems to me important.
They claim that "detecting electric field F" is the same as "taking there to be something edible". Similarly, I assume, they will take "detecting odorant O" is the same as "taking there to be something edible". (See panel c.) But, by transitivity of identity, this leads to the view that "detecting electric field F" is the same as "detecting odorant O".
The cognitivist doesn't have this problem, since "detecting electric field F", "detecting odorant O", and "taking there to be something edible" are different. The former two can be used as premises in an inference to the last.
Kalmijn, A. (1971). The electric sense of sharks and rays. Journal of Experimental Biology, 55, 371-383.