Fish, wildlife and drought |

MassWildlife has received questions about how fish and wildlife are responding to current drought conditions. It’s important to remember that New England’s fish and wildlife have adapted to the vagaries of weather, including harsh winters and droughts. However, extended drought conditions can have the most direct and severe impacts on fish communities and fish habitats. Here are some examples of the effects drought can have on some fish and wildlife.

fish stream It suffers from a reduced quantity and quality of habitat as reduced surface and groundwater influx compresses it into ever-decreasing and isolated pools of water. A decrease in the amount of cold groundwater can alter the quality of the remaining ponds, which can have significant effects on trout and other fish. Stagnant water heats up rapidly in the summer resulting in a loss of dissolved oxygen needed to keep fish alive. When fish become trapped in small ponds, they also become easy targets for a range of predators ranging from herons and raccoons to large fish in the same pond. There is also an increased potential for disease outbreaks and reduced reproductive success of fish during drought. Some very small scales can dry out completely. In these extreme cases, the fish may take months or years to recolonize the affected areas. As droughts increase in severity and duration, the effects felt by headwater currents are transmitted to larger systems and affect fish communities on an ever-increasing scale.

MassWildlife monitors fish communities to gain a better understanding of the effects of drought in human-dominated landscapes. Currently, MassWildlife is collaborating with the United States Geological Survey (USGS) to study changing flow patterns and elevated temperatures in flows across the state. The goal of this project is to identify areas, called climate change shelters, that are likely to change at least in the coming decades.

Lake and pond fish They are generally less affected by drought than those who live in streams, but prolonged drought can have effects. Very shallow ponds with dense vegetation experience large fluctuations in dissolved oxygen levels. The ability of water to hold oxygen decreases as the water temperature increases. This is exacerbated when, at night, aquatic plants begin to consume oxygen. As drought lowers water levels in already shallow ponds, these oxygen level fluctuations become more severe and can lead to fish deaths.

Whether in lakes, ponds, streams, or rivers, anyone who witnesses a fish killing for any reason should report the 24-hour Massachusetts Environmental Police radio room at 1-800632-8075.

trout storage This fall may be affected by drought, although it’s too soon to tell. It’s hard to predict droughts in the Northeast because, unlike western countries, we don’t have snow mass in the high mountains to monitor. Long-term precipitation predictions are difficult to make, so variables such as stream flow and groundwater levels are some of our best ways to monitor drought. Trout storage usually begins in mid-September, depending on the temperature. Reduction of some trout stocks in rivers and streams may occur this fall due to lower flows, but few impacts on lake and pond stocks are expected. MassWildlife fisheries biologists will assess the condition (temperature, flow, etc.) of each watershed before making a final decision on storage.

bear Rely on summer berries, which can dwindle as drought continues. As a result, bears search for other types of food which causes them to visit residential areas more often in the year. In dry summer, nuisance bear complaints tend to be higher because bears frequently use residential areas, taking advantage of bird feeders and litter. Dry summer conditions can also affect the timing and quality of fall oak crops, an important food source for bears. This can cause bears to seek food in agricultural areas and can damage crops.

Spinner You’ll likely experience few direct effects from dehydration, as deer browse a variety of food sources. Extreme drought conditions can cause deer to congregate in areas where food and water are more readily available. Establishing deer drinking water sites is strongly not recommended because artificial concentration of deer on small bodies of water increases the risk of disease transmission among deer.

Giant American deer Also browse a variety of food sources, but you’re more likely to experience stress during hot, dry conditions. Moose seek shelter from the high temperatures in forested wetlands and use mud and shallow water for cooling. When wetland areas begin to dry out during a drought, moose can struggle to shed the heat.

waterfowl It can fly like ducks, geese and swans into bodies of water with the right levels of water when needed.

Turkey You are likely to experience some negative effects. In general, turkey populations are more sensitive to spring weather conditions and to predators in the nest.

beaver It has the ability to regulate water levels, so if the water becomes too shallow, it may increase dam building activity. If they cannot raise the water level through additional damming, beavers may leave the wetland in search of deeper water.

Learn more about drought conditions and actions you can take to conserve water.

Stream image courtesy of Theodore buffet.

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