Punxsutawney Phil saw his shadow on groundhog day yesterday. This means, according to some ‘experts’, that we will have to endure another 6 weeks of winter. What does this mean for all of his fellow pond wildlife that live in and around our backyard ponds who need to wait a little longer until spring arrives?
The gold fish in your pond are one of the most tolerant of pond wildlife to a lack of oxygen that can be created by ice on ponds which is then covered in snow. However they do need oxygen and wont survive long without. This is true even though they are less active and require less oxygen now than they do at other, warmer, times of the year. Other types of fish including Koi are a lot less adapted to cold and low oxygen levels.
Frogs will usually hibernate at the bottom of your pond in the sludge and leaf litter. They can tolerate low oxygen levels but can’t survive in a pond that is totally de-oxygenated. Ponds will not usually freeze solid so they can wait out the cold at the bottom of your pond. However there are 5 breeds of North American frogs that can actually survive being frozen but these are the exceptions not the rule, most would not fare as well frozen!
Tadpoles also occasionally overwinter in the water when they don’t develop fully during the summer and autumn. No-one knows much about their survival chances overwinter: but it is likely that keeping the pond in generally good shape is the best thing you can do.
Most other pond life such a beetles and other invertebrates in your pond will probably be fine as long as the pond doesn’t become de-oxygenated completely. The simplest thing to do is make sure that your pond plants are getting some light and can go on producing oxygen under the ice. If your pond is covered in snow it will be completely dark under the ice, stopping submerged plants and algae from photosynthesizing and creating oxygen. Carefully sweep away as much of the snow as you can to allow the light to reach the plants. Clearing the snow away is probably the easiest thing to do. However most of our ponds in our yards have more wildlife in them than would occur naturally so simply relying on natural oxygenation from pond plants may not create enough for your pond life to remain healthy.
Running an air pump would certainly increase the oxygen in your pond and its water circulation. It will also help a hole remain in your ice which helps with gas exchange and lets undesirable gases escape. However having a hole in the ice wont in itself let much oxygen into your pond because oxygen diffuses into water extremely slowly. Having a hole in the ice will also let other wildlife that visits your pond be able to get a drink such as birds, foxes, deer, raccoons. An air pump will certainly oxygenate your pond and add some water circulation which benefits fish and other pond wildlife. I think your wildlife will survive this additional 6 weeks of winter but as pond owners we can also help them with the addition of an air pump into the pond.