The Dynamic Controls Shark, as with all recent wheelchair controllers, uses a proprietary version of CAN bus. If that connector is for the cable from the joystick pod to the power module, and you want to interface with that, you will have to do so using CAN bus serial communications. That also means that you would have to "sniff" out all of the CAN messages that the Shark system is using as Dynamic is not going to tell you what they are.
If that connector is a joystick-pod internal connector that connects the joystick to a circuit board, and if all 5 leads are in use, and you can't find some one who knows what the Shark uses, you may have to measure voltages from each to ground to figure out what each is carrying as there are a variety of Hall-effect or inductive joysticks in use in different systems. At a minimum, 4 leads are needed for a two-axis joystick: Vcc (usually 5V), GND, X output (variable, often something like 0.5 to 4.5 V, with out of range being sensed as a failure), Y output. A fifth lead could be a number of different things depending on the joystick: Vref (midway between Vcc and GND), or a center-detect signal, or other. If you google for "Apem", you can get an idea of the range of joysticks produced by one manufacturer that sells to the wheelchair controller industry.
You might also want to post your question at http://www.wheelchairdriver.com/board/
and ask if anyone there is familiar with Shark internals. I have a fair knowledge of some of the Dynamic DX modules, but not of the Shark.