## 1 Introduction
Since the ocean can be as deep as 10 km, the range of vertical transceivers must be longer than that of the horizontal transceivers as used in deep water applications [11]. Parallel number of communications usually occur in multiple forms from the sinks that are deployed, therefore, to handle these issues the surface station has been equipped with an acoustic transceiver. The surface station can also communicate to the onshore sink (OS-sink) or surface sink (s-sink) using longer range of the radio frequency (RF) or satellite transceiver. There are many challenging factors which characterize the unique features of UASNs. These factors are:  
1. Sensor nodes are energy constrained because they are battery powered. 2. The propagation delay of acoustic channels is five orders of magnitude slower than RF signals in terrestrial channel due to low speed of sound which is 1500 m/s. 3. The bandwidth is limited and depends mainly on the distance because of high transmission loss with high frequencies and high environmental noise with low frequencies [13]. 4. Nodes are prone to failures due to corrosion and fouling. 5. Fading and multipath problems make the acoustic channel impaired severely [2; 3]. Formation of shadow zone and temporary loss of connectivity in a region where the reception of underwater signal is impaired due to fading and multipath. As the networks become highly populated and more congested, cooperative communication methods grow rapidly and gain attention as a way in which distributed nodes in sensor networks or ad hoc networks with multiple antenna systems can cooperate to achieve performance gains [14]. The unique characteristics of underwater channels make communication very challenging as the underwater nodes cannot directly use the protocols designed for wireless terrestrial scenarios [15; 16]. In some underwater applications where autonomous underwater vehicles (AUV) exist, due to the high mobility of AUVs, cooperation within the nodes can be a major challenge which affects the overall performance of the network [17]. However, addressing AUV mobility challenge is not within the scope of this review. Cooperative forwarding (routing) can be achieved when the nodes involved in the routing vector agree to participate and cooperate with each other. However, the possible existence of malicious nodes in the routing vector makes cooperation a very challenging issue. It is necessary to provide a suitable cooperative mechanism across multiple authority networks specifically designed for an UASN in order to achieve an effective cooperative performance among sensor nodes in UASNs. Underwater networks are more vulnerable to malicious activities due to their challenging characteristics such as high BER, high propagation delay, and low speed of sound, corrosion and bandwidth limitation with its dependency on both distance and frequency [18]. Although, several cooperative techniques have been proposed, more research is needed in the aspect of cooperation to guarantee the reliability of data packet transmission over a network between the sender to the target, as there might be possibilities of having malicious, compromised or selfish agents along the transmission path that would attack, compromise or damage data packets. In this paper, we aim to investigate game theoretic strategies to support node cooperation in UASNs, in order to secure and effectuate data packet transmission over multiple authority networks. A game theoretic cooperation evaluates players' cooperation by modelling a two-person game and determine their level of cooperation based on their utilities (payoff) obtained in the game. Therefore, we have conducted an extensive investigation reviewing various factors affecting cooperation in UASNs where network consist of normal and malicious nodes. We study various cooperation techniques used for UASNs from different perspectives while concentrating on security and present a taxonomy for underwater cooperation.