What is healthy fish habitat?
So you think there are fewer, smaller fish in your local waterway? Take a good look at your brook ...is the bottom silted? Is it flat straight across? How often are there pools? Do the banks have trees and shrubs?
Ask yourself if there been changes to the watercourse or to the land upstream and inland. And in the end, ask yourself what constitutes healthy fish habitat?
A combination of things from above, below and within the water makes up healthy fish habitat.
From above, forested streambanks provide shade for cooler temperatures, overhead cover from predators, food and nutrients from falling leaves, insects and other organic matter to the fish and aquatic insects. Well-vegetated streambanks also serve to stabilize banks from erosion and clumping while allowing the formation of undercuts for cover.
A healthy stream needs sunlight to warm waters to enable fertilized eggs to hatch. The sun is also required for plant growth to feed insects and provide instream cover. A good stable insect population will provide fish with a stable food supply.
Too much sun can be a bad thing resulting in elevated water temperatures, so healthy fish habitat needs lots of big leafy trees. Trees provide shade from the summer sun, organic matter in the form of leaves, hiding places for fish when the tree falls into the water and strong root systems that help to stabilize stream banks.
From below, a healthy stream has a pool and riffle sequence which will sort the substrate, clean out gravel by "plowing" silt and sand to the banks and, over time, deepen and narrow the stream channel.
Much greater diversity of habitat niches is created for with clean gravels for spawning and nursery habitat as well as aquatic insect habitat, pools for overwintering, summer refuge and space for larger fish healthy fish habitat requires clean cobble to lay eggs in, larger stones to provide cover for juvenile fish and insects, and much larger rocks to provide resting places for migrating fish and to provide deflectors to help keep the water well oxygenated and moving fast which helps to create deep pools and clean out any silt.
From within, healthy fish habitat requires clean, cool water. The pH can not be too basic, or too acidic or the insect and fish eggs will not develop to hatch. As well, excess siltation, clouding up the water will eventually settle to the bottom and cover the unhatched eggs.
If a stream has a healthy insect and fish population, then you know the area above, below and within that stream is healthy.
Threats
Streams in Nova Scotia are 5-20% as productive as they once were. Two hundred years of land and water use have resulted in over-widened, silt laden streams and rivers. Land clearing leads to fast runoff during rain events, snow thaw and spring freshets. Higher high flows and lower low flows mean that there is more erosion during floods, warmer, shallower water in summer and increased freezing (right to the bottom) in winter. Dams, acid rain, silt and other pollution also cause major losses to fresh water fish habitat. But, we have the ability to reverse some of these impacts.
Many everyday activities harms fish habitat. Everytime you turn on a light, the electricity required may have come from a hydroelectric dam that is blocking fish migration, or a fossil fuel generator which is producing acid rain emissions that will settle on our rivers making the water too acidic to sustain life.
Maybe the tomato on your plate came from a farm that has cut away all the trees from a stream bank to create more room to grow food. As a result, the stream is left exposed to the direct sun and when it rains, silt from the farmers field clogs the stream bed. Or his fertilizer runs off the land and into the river resulting in poor water quality.
Or maybe the farmer has installed a system of drainage pipes in his field to move water off more quickly. Faster drainage means increased stream water speeds leading to erosion. Maybe if they let the water sink into the ground, it would be slowly released into the river and we would have much better water levels all year round.
What about the lumber being used to build your home? Was it harvested in a manner that respected greenbelts around stream banks, or was it cut off a stream bank, leaving the stream exposed to the sun and open to future deposits of siltation? Clearcuts cause streams to swell very quickly during a rain and loose their water very fast afterwards. This quick filling and emptying results in higher water speeds leading to further erosion and loss of fish habitat. In the winter, shallow water will freeze to the river bottom and during the spring thaw, act like a bulldozer rip up all the fish eggs and destroy nursery habitat.
As well, has the forest contractor built roads and bridges to protect valuable nursery habitat from erosion or do they just drive their machines through them?
Is there a mine in your watershed? If so, how are they treating there waste products? Is it being flushed into a local stream? The siltation and chemicals from many mining processes will both clog stream beds and poison river water.
But what about you and me .. how do we affect local fish habitat?
First, the storm drains on your street. Do you ever dump old paint, gasoline or the soapy water used to wash your car down the storm drain? If so, ask yourself where it goes. Right into the local stream killing fish with the chemicals and choking off fish habitat with silt.
Next time it rains, take a drive over to the local mall and watch where all the rainfall goes. You guessed it, its funnelled down through a system of manholes and out a pipe into a local stream. Check out the speed of the runoff. The next day, come back and see of there is any flowage out of the same pipe. Imagine all that rain water gone in one day.
What about your fertilizers? Are you using an organic fertilizer, if not, where do you think the chemicals end up?
In brief, we have cleared far too much land, we devise ways to get water off the land before it has time to sink into the ground to be cleansed and slowly released to our rivers and we are still using our rivers as garbage dumps.
So, what can you do?
Away from the rivers, NSSA is addressing all of these fish habitat issues. From meeting with various government departments, to advising the Minister of Fishing and Aquaculture on fisheries issues, to recruiting industry to practice more environmentally friendly strategies, healthy fish habitat is becoming the standard, not the exception.
On the rivers, NSSA has administered the 3 year, $1.16 million Adopt-A-Stream program under the Canada / Nova Scotia Cooperation Agreement on Economic Diversification. Funding for approved projects is provided on a cost-sharing basis with community groups contributing at least 50% of the project value. The AAS program budget started in October 1997 and expires March 2001.
The projects supported by Adopt-A-Stream thus far have been varied. Most of them focused on smaller rivers and tributaries - the life blood of watersheds. Restoration efforts included debris jam removal, placing digger logs and small rock sills with a goal of improving water flow and fish passage and of creating or repairing spawning and nursery habitats (winter and summer), and reducing erosion.
In larger rivers such as the Margaree, the West River Antigonish and the Sackville, larger structures and bank rip-rap were used; the expected results of these projects include improved fish migration, pool creation and reduced erosion. In the Cornwallis, half-log devices were placed in the main channel creating much needed cover for brown trout.
Adopt-A-Stream also supported two fishway projects: a small one on the Medway system in which adjustments to the previous year's work were needed, and a larger one on the Nictaux River.
Population enhancement is also a component of the program. Materials for trout incubation boxes were purchased, and a pilot project was established using in-stream incubation units for Atlantic salmon.
Total results of projects undertaken to date:
* 44 projects - 34,760 trees planted
- 20,770 volunteer hours logged
- 52 kilometers of streams restored
- economic net gain - $1,567,452.92
- 125 jobs created
What is more difficult to measure is the important impact fish habitat restoration projects have in educating people about the sport fishery and about our river ecology. Projects often attracted local media attention which in turn increased community awareness of a group's effort, and often resulted in offers of help and support. George Ferguson, NSSA Director and AAS Committee Chair asserts "Early in the next millennium, our Adopt-A-Stream projects will start paying dividends in improved sport fisheries, to the credit of effective, locally led conservation groups and the financial assistance of the Economic Diversification Agreement."
Once healthy fish habitat can be restored to its original state. Restoration efforts in Brierly Brook and the West River in Antigonish were closely monitored by the Fisheries and Oceans' Habitat Branch and the data showed enormous increases in juvenile populations and adult spawning exceeding a 6000% increase.
Many habitat problems can be addressed using techniques currently available. Before deciding on the approach some investigation is needed to determine what are the limiting factors to fish populations in an area. Restoring your stream will involve not only work in and near the stream but also discovering the source of the problem and hopefully working with others in the watershed to find solutions.