## 3 State-of-the-Art Review
### Related Projects, Systems and Applications
\begin{table}
\begin{tabular}{|p{42.7 pt}|p{42.7 pt}|p{42.7 pt}|p{42.7 pt}|p{42.7 pt}|p{42.7 pt}|p{42.7 pt}|p{42.7 pt}|p{42.7 pt}|p{42.7 pt}|p{42.7 pt}|p{42.7 pt}|} \hline \hline [PERSON] _et al._[52] & Zhejiang University of Technology & China & 2009 & Monitoring marine shellfish & Water temperature, pH value, salinity, DO and COD & GPRS &? & Solar battery & Tested in an aquatic experimental base & Multi-hop communication protocol, multiple nodes, and SMT base \\ \hline [PERSON] _et al._[53] & Ocean University of China & China & 2009 & Ocean Sensing \& monitoring & Temperature, velocity and light & ZigBee & Lever buoy & Battery & Depployed off the the eschnism and lever buoy & The sleep mechanism and lever buoy \\ \hline [PERSON] _et al._[54] & China Jiliang University & China & 2010 & Water quality monitoring & Temperature, pH, DO, and salinity & ZigBee &? & Battery &? & Two wireless communications of ZigBee and GPRS \\ \hline [PERSON] _et al._[55] & Shanghai Ocean University & China & 2010 & Ocean Sensing \& monitoring & Water temperature, DO and pH & ZigBee & Buoys with GPS \& PEA &? & Experimental in two testbeds & Position determination and location verification using GPS\& PEA; Booys using GPS\& PEA; Booys with and \\ \hline [PERSON] _et al._[56] & Politecnico di Milano, Milano & Italy & 2011 & Ocean Sensing \& monitoring & Scawater luminosity, temperature and moisture & ZigBee & Cylinder waterproof & Solar energy harvesting, Power-aware protocol & Optimal solar energy harvesting; Power-aware and adaptive TDMA protocol \\ \hline [PERSON] _et al._[57] & National University of Patagonia San & Argentina & 2011 & Ocean Sensing \& monitoring & Temperature, pressure, PAR radiation, pH and salinity & ZigBee & Cylinder waterproof & Solar panels & Tested in San Jorge Gulf & A low cost reconfigurable WSN; Booys; Solar panels \\ \hline [PERSON] _et al._[58] & Kuwait University & Kuwait & 2012 & Water quality monitoring & Water temperature, DO, and pH & ZigBee &? & A high-capacity & Tested in a water pool & Using ZigBee and water pool 802.11 Ethernet radio & Using ZigBee and and a high capacity solar panel & 802.11 Ethernet radio and a high capacity solar panel & Tested in a water pool & Using ZigBee and and a high capacity solar panel \\ \hline [PERSON] _et al._[59] & Technical University of Cartagena & Spain & 2012 & Ocean Sensing \& monitoring & Marine temperature and pressure & ZigBee & Special buoy & Solar & Depployed in Mar Menor & A new multisensory buoy system and solar panels \\ \hline \end{tabular}
\end{table} 
Table 3: \(Cont.\)It can be found that most of the efforts are related to general ocean sensing and monitoring [4, 23, 40, 44, 46, 47, 50, 53, 55, 56, 57] and water quality monitoring [39, 42, 43, 49, 51, 54, 58]. Some specific efforts have been made for fish farm monitoring [45, 48], coral reef monitoring [41], and marine shellfish monitoring [52]. Some projects focus specific technologies or devices, e.g., buoys [23, 40, 53, 57, 59] which will be further discussed in Section 4.2, and energy saving and harvesting [4, 43, 48, 50, 52, 56, 57, 58, 59], discussed in details in Section 4.3. Most developed systems were only experimented in lab settings or indoor environments [39, 45, 46, 52, 55], some are tested in outdoor pools or small ponds/lakes [40, 42, 48, 58], and a number of them have been tested or deployed in real marine or river environments [4, 23, 41, 43, 44, 47, 49, 51, 53, 57, 59]. It is also interesting to note that during the last decade most projects, systems and applications have been developed by research groups in a small number of countries, including USA [39, 40, 41, 42], China [52, 53, 54, 54, 55], Spain [4, 45, 46, 48, 59] and Ireland [43, 49].