|
[Descriptions
| Habitat
| Surveys
|Safe to Eat?
| Natural Community
| Fish Stocking
| Fishing
in the Assabet Watershed | Back
to Main]
Fish Classifications Based on Habitat
Requirements
All fish need water to live, but some fish need flowing water
for all or part of their lives, and some don’t. We tend
to think of rivers and streams as flowing water, but dams
made by people and beaver, change portions of rivers and streams
into de facto lakes and ponds called “impoundments”,
by holding back flow and reducing the time it takes for water
to move downstream. During the summer time, pumping water
directly out of a stream or from a nearby well can also reduce
flows or even dry up a river or streambed by reducing the
total volume of water in the river or stream. In general,
natural, free-flowing rivers and streams are dominated by
fish species that need flowing water for at least part of
their life cycle.
Specifically, the fish in the Assabet River and
Assabet streams can be divided into general categories or
“classes” depending on their habitat requirements;
fish that need flowing water for all or a portion of their
life cycle, and fish that don’t. Fish that need flowing
water throughout life, such as brook trout in southern New
England, are called “fluvial specialists,’ and fish,
such as white suckers, that need flowing-water for spawning
or another specific life stage, are called “fluvial dependents”.
Fish such as bluegills that can live in a wide range of habitats
including lakes, reservoirs and streams, and are able to complete
their live cycle in any of these systems are called “macrohabitat
generalists.”
By looking at the composition of the fish community
present in the Assabet and its streams today, i.e. numbers
of fish of each species and their flow requirements, we can
determine the health of the fish community in the Assabet
River and streams compared to other rivers in New England.
Three Classes of Habitat Requirements
Fluvial Specialists
These fish species are almost always found only in streams
and rivers or are described to use flowing water habitats
throughout life. Occasionally a fish may be found in a reservoir
or lake but the vast majority of the fish live in flowing
streams.
Fluvial Dependents
These fish species are found in a variety of habitats but
require access or use of stream habitats or flowing waters
at some point in their life cycle. These fish species may
have significant lake or reservoir populations that use tributary
streams for some life requirement. Species may be described
as primarily riverine fish but can be found
Macrohabitat Generalists
These fish species are commonly found in lakes, reservoirs,
and streams and are capable of completing their life cycle
in these systems. These fish live in highly diverse habitat
types over wide geographic areas. In other words, these fish
are very adaptable and can live almost anywhere.
See the table below and the species descriptions
under Fish Species Present in the Assabet
River and tributary streams to find out about the habitat
requirements of fish living in the Assabet River and its tributary
streams.
Table: Habitat Classification of Assabet River
and Tributary Fish
back to top
|
