https://en.wikipedia.org/wiki/United_States_Navy_Marine_Mammal_Program
A major accomplishment was the discovery that trained dolphins and sea lions could be reliably worked untethered in the open sea...In 1967 the NMMP was classified and has since evolved into a major black budget program.[3] The Point Mugu facility and its personnel were relocated to Point Loma in San Diego, and placed under the control of the Space and Naval Warfare Systems Center San Diego...
There are five marine mammal teams, each trained for a specific type of mission. Each human-animal team is known in military jargon by a "mark" number (MK for short); the five teams are called "MK 4", "MK 5", "MK 6", "MK 7", and "MK 8". The MK 4, 7 and 8 teams use dolphins; MK 5 uses sea lions, and MK 6 uses both sea lions and dolphins. These teams can be deployed at 72 hours' notice by ship, aircraft, helicopter, and land vehicle to regional conflicts or staging areas around the world
MK 4 uses dolphins to detect and mark the location of tethered sea mines floating off the bottom, while MK 7 dolphins are trained to detect and mark the location of mines on the sea floor or buried in sediment. The MK 8 team is trained to swiftly identify safe corridors for the initial landing of troops ashore.
Force protection
MK 6 uses dolphins and sea lions as sentries to protect harbor installations and ships against unauthorized human swimmers. MK 6 was first operationally deployed with dolphins during the Vietnam War from 1965 to 1975 and in Bahrain from 1986 to 88.[6] When an enemy diver is detected by a dolphin, the dolphin approaches from behind and bumps a device into the back of the enemy's air tank. This device is attached to a buoy which then explodes, alerting the Navy personnel of the intruder. Sea lions carry a similar device in their mouth, but instead attach it by hand-cuffing one of the enemy's limbs. The animals depend on their superior underwater senses and swimming ability to defend against counterattacks.
MK 5 is dedicated to the recovery of test equipment that is fired from ships or dropped from planes into the ocean; the team uses California Sea Lions to locate and attach recovery hardware to underwater objects such as practice mines. In this role they can out-perform human divers, who are restricted to short working times and limited repeat diving.
This team first demonstrated its capabilities when it recovered an ASROC (Anti Submarine Rocket) from a depth of 180 feet (50 m) in November 1970. The team has trained in the recovery of dummy victims in a simulated airplane crash.
It has been reported that the program will come to a close beginning in 2017, when the mammals will be replaced by robotic mine-hunters such as the General Dynamics Knifefish.[1]
http://www.cnn.com/2016/03/10/europe/russia-military-dolphins/
While the new dolphin brigade's purpose is not evident from the purchase order, Ukrainian war-dolphins found themselves forced to change allegiance following the Russian annexation of Crimea in 2014.
"The combat dolphin program in the Crimean city of Sevastopol will be preserved and redirected toward the interests of the Russian navy," state-run Russian news agency RIA Novosti reported at the time.
Combining the captured Ukrainian dolphins with the additional five being purchased (including females, possibly as breeding pairs), and the US planning to decommission all Marine Mammal System units this year, there is an imminent dolphin disparity. We must not allow a dolphin gap!