Forward Post: AFS Journal What Exactly Is Fish Habitat and Why Must We Care?
Mon Jun 3, 2013 2:29pm What Exactly Is Fish Habitat and Why Must We Care?Thomas E.
Bigford Office of Habitat Conservation, NOAA/National Marine Fisheries Service, Silver Spring, MD 20910.
E-mail: Thomas.bigford@noaa.gov “Fish habitat” is a simple term.
We can easily imagine a fish languishing under a log or in a kelp forest, and we can picture a school of forage fish zipping through the water column.
We can also grasp that the preferred space for many species might change as the seasons change and the years pass by.
But the rest of the story is not quite so simple, mostly because life is more complicated and knowledge is often limited.
This month’s “Fish Habitat Connections” seeks to demystify those details so we can appreciate the intricacies in the fish habitat world and become more emboldened to serve fish not just as a meal but as they deserve.
Let’s begin with semantics.
Each fish occupies its preferred niche in the ecosystem.
The environmental conditions of that space define the fish’s preference at each life stage—water temperature, depth, salinity, flow, bottom type, prey availability annual cycles, and much more.
It is important for us as professionals to place those variables in proper context so that individual fish can survive, fish stocks can flourish, fishery management can succeed, and society can benefit from our nation’s waters.
That simplistic summary reflects our hopes, which are complicated by the reality that we know very little about our most basic habitat questions.
With luck, we know where fish live throughout their life cycles.
But oft times we have few insights into the shifting preferences of each life stage.
Even that knowledge is elusive unless we have close observations from multidecadal stock assessments or the insights offered by a healthy fishery.
Almost universally, we rarely understand the relationships between fish and their habitat.
If a wetland is dredged, how will the local fish populations change over the short and long term?
If a dam is breached, will the new hydrological regime support native species or invite invasive species?
If an acre is protected or restored, how will the population respond?
Will harvests increase?
These issues read like the final program at many an American Fisheries Society (AFS) conference.
They have vexed us as a profession for decades.
We must manage fisheries with the best available information, scant as it might be.
And we must identify our primary needs so that gaps are addressed.
COLUMN Fish Habitat Connections There is also the still-new concept of ecosystem-based approaches.
Habitat must be an essential variable in stock assessments, but those analyses must be conducted with an ecosystem in mind.
Those perspectives can be as important as data.
Without that challenge, we won’t even know we have a data gap.
Considering how complex this simple topic can be, and how it reflects human pressures from our coasts to the mountains, it is probably no surprise that we continue to lose habitat function at alarming rates.
Along our oceans, marine and estuarine wetland loss was three times higher between 2004 and 2009 than in the previous 5 years (Stedman and Dahl 2008; Dahl 2011).
Inland wetland loss is not as severe, but hundreds of rivers representing thousands of river miles are compromised by blockages that prevent fish movement upstream or downstream.
The first-ever national fish habitat assessment found that 53% of our estuaries are at high or very high risk of habitat degradation (National Fish Habitat Board 2010).
Given those numbers, it is unfortunate that those places provide vital nursery habitats for many of our favorite fish.
As fishery professionals from all disciplines, our assignment is to combine our skills to protect important habitats and restore those that are degraded.
Our mission will be slightly less daunting if we and our partners can set a pace to match the steady pressure of human population growth and looming challenges such as climate change.
AFS represents an incredible knowledge base.
If anyone can analyze our habitat knowledge, fill our priority gaps, apply lessons learned, and improve habitats for the benefit of all, it is us.
More habitat articles at fishiding.com Next month we will shift from the nuances of semantics to the harsh realities of the challenge before us.
It is imperative that we engage now!
Economic and ecological facts urge AFS, its units, each of us, and our home institutions to accept the challenge.
We will explain the opportunities before us and how our collective skills are needed for success.
REFERENCES Dahl, T.E.
2011.
Status and trends of wetlands in the conterminous United States 2004-2009.
U.S.
Department of the Interior, Fish and Wildlife Service, Washington, D.C.
108 pp.
National Fish Habitat Board.
2010.
Through a fish’s eye: the status of fish habitats in the United States 2010.
Association of Fish and Wildlife Agencies, Washington, D.C.
68 pp.
Stedman, S., and T.
E.
Dahl.
2008.
Status and trends of wetlands in the coastal watersheds of the Eastern United States 1998 to 2004.
National Oceanic and Atmospheric Administration, National Marine Fisheries Service, and U.S.
Department of the Interior, Fish and Wildlife Service, Washington, D.C.
32 pp.