fish report header

Defining What is Essential

August 4, 2014


On any given day, a number of human activities may alter the environments where protected fish species live. From building a bridge to operating a hydroelectric power plant, these activities are elemental to the function of many towns and cities. At the same time, there is always a need to protect our natural resources and operate responsibly with the least feasible impact. As a result, regulations are developed with the intention of meeting this charge. While regulations are deemed necessary for the protection and survival of wildlife and other aspects of nature, they can be controversial because they impose limitations on human activities.


Since few people find pleasure in reading detailed legal text, here we offer just a brief primer on fisheries regulations to spare the masses. The Magnuson-Stevens Fishery Conservation and Management Act is a law developed in 1976 by senators from Washington State (Warren Magnuson) and Alaska (Ted Stevens) with environmental protection in mind. The law focuses on anadromous fish stocks and other marine harvested species, and affords protection for these species through Fishery Management Plans (FMPs). These plans limit human activities within areas of habitat designated as important for the species' survival, which is called Essential Fish Habitat (EFH). Generally, the law guides fish harvest and general take, but it can also influence other activities, such as those that occur in fish spawning and rearing areas of rivers.


In the past, the Magnuson-Stevens Act focused on monitoring areas of spawning habitat in the portion of rivers and the ocean (up to 200 nautical miles offshore) that fish can currently access. Regulations influenced issues like fishing quotas, development activity, and other environmental review processes. However, recent proposed revisions may significantly expand the scope of the law to require fish passage above existing dams to increase accessible spawning habitat.


In the suggested revisions, the National Marine Fisheries Service (NMFS) proposes to take a fish species' historical distribution (from earliest available records) into account when considering which habitat is essential to protected fish species. These historical ranges may include river reaches above locations where dams now exist. The revised regulations also suggest that these changes to Essential Fish Habitat may go into effect whenever any new, relevant data is identified, which would streamline the review process. In the current state of the law, revising Essential Fish Habitat is a more gradual process.


Reaction to this type of legislation is bound to be mixed and generally polarizing. Some parties argue that fish should be able to access their entire historic ranges for spawning and rearing, regardless of the presence of dams. Estimates of lost habitat sitting behind dams varies, but some have suggested 40 percent of historical West Coast salmonid habitat is no longer accessible. Other people maintain that many fish species are not critically limited by lack of habitat, but rather are primarily impacted by other issues, such as unnaturally high predation rates from introduced game fish that were historically stocked by resource managers. Recent research in a Central Valley tributary of the San Joaquin River showed that predation on juvenile salmon can exceed 90 percent of the outmigrating juveniles. Combating unnaturally high predation levels is a successful strategy implemented on the Columbia River (PDF). Increasing access to habitat may increase the number of outmigrating salmon, but without addressing the predation issue, this may simply result in a more abundant and expensive menu for hungry bass and other game species.


Expense is also a significant consideration in increasing access to fish habitat. For this reason, fish passage projects are most commonly found on smaller facilities, and few exist on higher capacity reservoirs. From 1987-2002, there were only 10 Federal Energy Regulatory Commission (FERC) projects on the West Coast with fish passage requirements (FERC 2004). Fish passage was recently assessed on the relatively sizeable Oroville Reservoir, but was deemed financially unreasonable compared to other alternatives. While financial impracticality was a major factor leading to this habitat expansion opportunity being passed over, the decision may have been different under the current proposed revisions to the definition of Essential Fish Habitat.  Implementing an effort of this magnitude would have levied financial burden onto tax dollars and utility bills for years to come.


Finding a balance of human activities and healthy wildlife populations is an ongoing challenge, and priorities are always a topic of concern. While there are not any right answers in these debates, there can always be discussions of the most effective and practical solutions. The best pathway forward can be determined through involvement and comments from the private sector, non-governmental organizations, and the public. Staying informed and involved in these issues helps ensure good decisions are made.

Follow Us! Like us on Facebook Follow us on Twitter View our photos on flickr View our videos on YouTube
email list
Recent Blog Posts
Miniature ear bones





Fishes can hear (and produce) quite a range of sounds, as we discussed in our recent Fish Report, "The Symphony Aquatic." One of the mechanisms by which fish hear is through bony structures called otoliths, which are also referred to as "earstones." Pressure from sound waves causes the otoliths to vibrate, which in turn stimulates cilia or hairs that provide sensory cues to the fish. Bony fish have three sets of otoliths: the sagittae, the lapilli, and the asterisci, shown in the photo above. These otoliths aid in balance and hearing. Otoliths also produce growth rings similar to trees, and this characteristic makes them useful in determining the age of a fish (see Rings in their ears).

A variety of fish structures, including otoliths, scales, opercula, spines, and vertebrae, can be used for ageing because their growth trajectory is predictable and verifiable. Otoliths grow by depositing layers around the nucleus, or center, which allows scientists to age a fish by years or even days. Researches can verify these ages by conducting a series of marking events with heat or chemicals, which create unique marks in the otolith of a fish while it is still alive. 

Once the otoliths are dissected from a fish, these marks are compared to known marking dates and provide scientists with reference points to count how many rings were deposited between the initial and last marking events. 


When it comes to larval fish, scientists determine ages and growth rates on the order of days. One of our biologists conducted such daily ageing of endangered larval suckers as part of his Master's thesis.

This thesis explored whether endangered larval suckers inhabited restored wetlands on the Sprague River in Oregon, and how fast they grow in this habitat. Adult suckers typically migrate in spring from Upper Klamath Lake to spawning areas on the Sprague and Williamson Rivers. Three sucker species inhabit this area upstream of Upper Klamath Lake. Both the Lost River sucker (Deltistes luxatus) and the shortnose sucker (Chasmistes brevirostris) are endangered, and the Klamath largescale sucker (Catostomus snyderi) is a species of special concern. 

There is no hatchery supplementation for these suckers; however, implementation of a controlled propagation program may be used to prevent extinction of the two endangered species (USFWS 2012). Larval suckers are often observed in the wetlands surrounding Upper Klamath Lake, as well as in wetlands on the Sprague River. These wetlands were restored under the Wetlands Reserve Program through the United States Department of Agriculture.

The study included larval suckers ranging from 9-28 mm in length. Larval suckers can be identified to species using a combination of pigmentation pattern and abundance, vertebral counts, and/or myomere counts... Read more > 

IN THE NEWS: Recent stories you might have missed...
Highway for fish

Chico News & Review 

A long-term plan aimed at restoring migratory fish habitat in Battle Creek inched forward July 26 as Pacific Gas & Electric Co. released a draft of the project's final phase for stakeholder review. Battle Creek flows in two forks, north and south, originating near Mount Lassen and connecting to the Sacramento River about halfway between Red Bluff and Redding. Fed by cold springs year-round, the waterway is less susceptible to drought conditions than most, and the shelter provided by the steep, remote canyons it runs through makes Battle Creek... Read more >  

Salmon are dying in the Salmon River because the water's too warm
Think Progress

Fifty-four adult and hundreds of young fish have died in California's Salmon River, due to low water flows and warmer-than-usual temperatures. A population assessment for Chinook salmon and Steelhead in the river found 300 to 600 juvenile fish - mainly Chinook - have died, prompting concerns over further reductions in the species' populations as California's drought persists. The fish are dying before they get the chance to spawn, due to drought and decreased snowpack-fueled low water levels... Read more >  

Recycling summer steelhead ending for the season
Statesman Journal

Today will see the last of the summer re-runs. Not the television variety, the summer steelhead version. To prevent hatchery steelhead from spawning with non-hatchery wild fish, trap-and-transplant programs - known as recycling - are ending today on both the North and South Santiam rivers. Beginning Friday, all hatchery steelhead not needed for hatchery production entering the traps at both the Minto Fish Facility on the North Santiam and at Foster Dam on the South Santiam will be processed and the meat distributed to food banks and other non-profit charities that feed the needy... Read more > 

California breaks drought record as 58% of state hits driest level   
Los Angeles Times 

More than half of California is now under the most severe level of drought for the first time since the federal government began issuing regular drought reports in the late 1990s, according to new data released Thursday. According to the U.S. Drought Monitor report, in July roughly 58% of California was considered to be experiencing an "exceptional" drought -- the harshest on a five-level scale...  Read more > 

The undersea drones revealing the ocean's secrets


When Typhoon Rammasun swept through the South China Sea in July, a tiny ship was trapped in its path. The deadly storm whipped up waves over 10 meters high and winds approaching 200 miles per hour. Any regular boat would have been smashed to pieces, but this craft just a few feet long sailed through without pausing in its work. The Wave Glider is an ocean drone developed by Californian start-up Liquid Robotics... Read more >