The study adopted ex post facto design. Using ship traffic, vehicle traffic, berth efficiency, turnaround time as input explanatory variables and output factors as average throughput to compare the pre concession and post concession. The six Nigerian ports: Tincan Island Ports, Apapa Port, Port of Delta Warri, Calabar Port, Rivers Port and Onne Port were sampled. It is observed that year 2014 is the most efficient year out of the 36 operation years in terms of output maximization with constant levels of inputs under the study period with score 1.0 respectively serving as 32 times benchmark for other years. It is observed from that Tin Can Island Port was technically efficient in the operation years of 1980, 1981, 1985, 1995, 1997, 1998, 2009, 2013, 2014 and 2015 with score 1.0. However, the most efficient operation years are 1998 and 2013 while the most inefficient year is with efficiency score 1.0. The post-concession years that the port was technically inefficient are 2006, 2007, 2008, 2010, 2011 and 2012.

This paper typically applied the concept of ranking by inspection using the dwell time of ships in five African ports to evaluate the variations in ship turnaround time and relative efficiency level. This is to identify the active factors that cause port congestion in African ports. The results provided some explanations on the consequences arising from these on notable African logistics and supply chain networks. The findings reveal that the bane of congestion in African ports emanates entirely from either planning, regulation, capacity, efficiency or a combination of these. The regression analysis with IBM SPSS v20 reveals that there is a significant relationship between cargo throughput and other port performance indicators in Nigeria for the study period (2005 -2014). More so, the t-test reveals that there is a significant relationship between cargo throughput and berth occupancy rate which is significantly indicative of port congestion. This paper therefore recommends that African ports should enhance their regulatory mechanisms, and also improve capacity and efficiency level in order to shoulder the ever increasing challenges of port congestion in years ahead.

The study examines the ecological and economic implications of dredging activities on fishing sites in the Niger Delta area of Nigeria. Data from secondary sources were empirically analysed and results show that dredging operations have significant effect on fishing sites. These are revealed by the magnitude of ecological and economic implications to the region, which is reflected by the level of economic value of damage caused by dredging in the area, the number of fishing sites and farm lands affected by the dredging operations. The study concludes that even though dredging is imperative for the economic survival of the area, there is need for routine studies to be conducted prior to the operations so as to ensure that dredging activities are executed in the most environmentally friendly manner in accordance to international best practices in order to mitigate ecological imbalance in the basin.