On Thursday, March 26th, Kevin Mann came in to talk with us about Lake Sturgeon Streamside Rearing operations. Kevin is a fish biologist with the US Fish & Wildlife Service, and he works out of the Green Bay Fish and Wildlife Conservation Office.
Lake sturgeon are a very long-lived species and don’t mature until they are ~ 12-20 years old. Because of this factor, their populations do not increase too rapidly. Therefore, outside factors have a highly negative effect on them. Pollution, dam blockage and overfishing have all led to the extirpation of many populations. Some agreed upon solutions include: create fishing restrictions/closures, keep water flow relatively constant below dams, and regulate river pollution. Another big way to have a strong positive affect is to engage in streamside rearing.
Streamside rearing is done from a mobile trailer that ‘raises’ the sturgeon within the water of the river they will likely return to. Lake sturgeon are a species of fish that use natal homing to return to the river they were raised in to spawn, so this is a crucial part of the process. Before the water enters the tank, it is filtered to remove sediment and then UV treated to removed bacteria. This is done to protect the fish from starvation and disease. To obtain the gametes needed for reproduction, there are two methods. For populations being re-established, they take eggs and sperm from the fish. For populations that are being supplemented, they use ‘egg mats’ that collect the eggs, and bring those into the facility to raise. They also collect larval sturgeon during drift periods. Once the fish reach a size of 6-10 inches, they are tagged – either with a coded wire tage or PIT tag – and released.