Golden algae are documented in Arizona

              5/1/12 Advisories: Fishing and Fish Consumption Advisories
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Golden algae are documented in Arizona
Advisories: Fishing and Fish Consumption Advisories
Apr 15, 2005
Golden algae were confirmed in Arizona waters recently and
while these microscopic organisms present new challenges to
managing our state's aquatic resources, they do not pose a
health risk to humans.
When there is a golden algae bloom, these tiny organisms
can release toxins that affect fish and other aquatic
organisms with gills, such as freshwater clams. A bloom
occurs when the organisms out-compete other algae and
experience a rapid population growth. Little is known about
what environmental conditions cause a bloom, but scientists
suspect it may be a combination of factors.
The Arizona Game and Fish Department has confirmed that
golden algae were responsible for fish kills at Water Ranch
Lake in Gilbert this winter. Steps are being taken this week
to flush the lake and treat it to remove the algae in this 5-
acre urban lake.
Biologists have also confirmed the presence of golden algae
in Saguaro Lake in the Salt River system. A recent shad die-off
in Saguaro Lake may be linked to golden algae, but there
is no indication that the shad die-off had any noticeable
effect on the fishing success of anglers at the lake. In fact,
most angler reports received by the department indicate
good angling success there.
Biologists say that algae blooms of this nature are
unpredictable: they are typically localized, but not always. It
is still unclear what conditions trigger the blooms, but it may
be a wide set of variables. Typically, golden algae have done
well in lakes with colder water and higher alkalinity, but
biologists say even those two factors seem to change at
times.
Biologists also stress that while golden algae have affected
fisheries in other states, there is no cause for alarm here.
The Arizona Game and Fish Department will continue to
closely monitor the situation to determine what effects
golden algae will have in Arizona and what options may exist
to address it.
Anglers and boaters who see dead or dying fish can help by
reporting observations as soon as possible to the Arizona
Game and Fish Department at goldenalgae@azgfd.gov.
Include the species and sizes of fish affected, approximate
numbers of fish observed, and the locations where fish were
observed. For your safety, please do not touch, collect, or eat
dead or dying fish.
To prevent transporting the alga to other waters, drain all
bilge areas and live wells of your boat before leaving the
lake.
Click here for a list of frequently asked questions about
golden algae.
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Golden alga frequently asked questions
What is golden alga and how does it kill fish?
Is it harmful to humans, pets or other animals?
Where does it occur?
How can it spread?
What are the signs of a golden alga bloom?
Can fish escape a toxic golden alga bloom?
What are the ecological and economic impacts?
Where else can I read about golden alga?
Does golden alga occur throughout the water column?
Will warm water cause a golden alga bloom to decrease?
How do scientists measure the amount of golden alga in
the water?
How do we get the answers we need?
What is the Arizona Game and Fish Department doing
about golden alga?
How can I help?
How can I learn about the most up-to-date information?
Alga or Algae?
What is golden alga and how does it kill fish?
The golden alga, Prymnesium parvum, is a tiny, one-celled
aquatic organism about the size of a human blood cell. The
alga is motile with two “tails” called flagella that help it to
move through the water in lakes and ponds. A single drop of
lake water may contain well over 2,000 cells of golden alga.
Biologists suspect that golden alga is relatively new to
Arizona and they consider it a nuisance invasive species.
Golden alga releases unique toxins that affect gill-breathing
aquatic organisms (mainly fish and clams). The alga is a rapid
growing and resilient algae species, out-competing other
algae for nutrients and thriving in a wide variety of
environmental conditions. In a bloom situation (a bloom is an
explosive increase in the population of one or several species
of algae), enough toxins are released into the water to kill
fish and other gill breathers that come in contact with it. The
toxins cause fish gills to bleed internally, and lose their ability
to exchange water and absorb oxygen. Fish then die of
asphyxiation (lack of oxygen).
Golden alga toxins have no apparent lethal or harmful effects
on animals that do not breathe through gills. The impacts to
fish populations vary and are most often temporary. Algae
blooms may last for days or weeks. Blooms may occur a
couple times a year, or not at all in some years. The
environmental conditions that support golden alga are broad,
and little is known about the specific and complex conditions
that allow it to gain a competitive edge over other species, or
about what causes a "bloom" that results in fish kills.
According to reports from other states and recent trends in
Arizona, the majority of golden alga fish kills occur during the
winter and spring months when water temperatures range
from 55-80 degrees Fahrenheit. Winter conditions are not
favorable for other, common kinds of beneficial algae normally
found in our inland waters, which likely gives the golden alga
a competitive edge.
Generally speaking, golden alga also prefers more saline
waters, which may also help a bloom get started. Although
factors such as water temperature and salinity are somewhat
helpful in predicting lake conditions suitable for golden alga,
there are also many documented exceptions in Arizona and
other states.
Is it harmful to humans, pets or other animals?
Golden alga blooms are not a public health threat. The golden
alga produces a unique toxin that damages gill functions and
causes fish to suffocate because they can’t obtain oxygen
from the water. The algal toxins are only harmful to gill-breathing
organisms such as fish and clams.
Arizona Department of Health Service officials have stated
that human health is not affected by exposure to golden alga
or their toxins. Studies indicate the toxins are not passed
through the food chain or absorbed into the flesh of fish.
Consequently, healthy fish caught from infested waters are
safe to eat. Still, people should exercise common sense: do
not pick up or eat dead or dying fish.
Cattle and other animals have been observed drinking from
rivers during ongoing golden alga fish kills in Texas with no
apparent adverse effects. The bottom line: golden alga
5/1/12 Golden alga frequently asked questions
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apparent adverse effects. The bottom line: golden alga
blooms are harmful to animals (fish and clams) with gills, but
the alga and their toxins don’t harm animals or people.
Where does it occur?
Golden alga was first identified in Arizona in April 2005. To
date, golden alga has been confirmed in various public and
private waters in the greater Phoenix area and in three
reservoirs on the Tonto National Forest.
Four Urban Fishing Program waters have been infested:
Water Ranch Lake (Gilbert), and Alvord Lake at Cesar Chavez
Park, Cortez Lake and Desert West Lake in Phoenix. It has
been found in Saguaro Lake, Canyon Lake and Apache Lake.
Golden alga was first discovered in the United States in Texas
in 1985. Since then, it has caused fish kills in five major river
systems and over 25 lakes or reservoirs in Texas. Texas
officials have estimated the direct economic loss of over 18
million fish due to golden alga as $7 million. This toxin
producing algae has now been documented from 12 states
ranging from North Carolina to Georgia to Wyoming to
Arizona.
How can it spread?
Nobody knows with certainty how golden alga is spread from
one body of water to another or how it was spread into
Arizona. It may travel along river or canal pathways, or by
businesses trucking products in water. Water birds such as
ducks, geese, herons and cormorants, or humans
transporting water in live wells, bilge tanks, minnow buckets
or wet clothing or equipment, may spread golden alga. Also,
the resting cyst stage of golden alga can reside in dried lake
sediments and potentially be dispersed by strong winds.
What are the signs of a golden alga bloom?
Water Appearance: When golden alga becomes more
abundant during a bloom cycle in a lake, the water begins to
turn yellowish, yellowish-copper or a brownish, tea color.
Another sign is foaming at the surface of the water in areas
where there is a lot of wave action or water is agitated or
stirred up. However, these conditions can also come from
other sources, and do not always indicate a golden alga
bloom. Additionally, golden alga has proven to be toxic in
waters where these visual conditions have not been readily
apparent.
Dying or affected fish: Fish exposed to golden alga toxins
may swim slowly or erratically just below the surface, lie
listlessly along the bottom in shallow areas, or show no
normal avoidance to human disturbance or presence.
The toxin affects gill-breathing fish and clams by disrupting
the uptake of oxygen across the gills. In the later stages, fish
will act as if there is no oxygen in the water. Fish will seek
areas with no toxicity or lower toxicity. If clean water flows
into a lake, fish will often concentrate in these areas.
Visible signs of exposure to the toxins include redness or
hemorrhaging at the base of fins, around the mouth area,
under the chin, and along the belly of fish. After prolonged
exposure, there is blood loss from broken capillaries
(hemorrhaging) of the gills, resulting in a pink or pale red
appearance to the gills.
Can fish escape a toxic golden alga bloom?
Yes, they can escape a localized bloom in a lake if there is a
nearby toxin-free area. Early effects of the toxin are
reversible if the fish can swim to a toxin-free area or an area
of low toxicity.
In a larger reservoir or lake with a complex shoreline and
varied depths, all of the fish may not be killed during a bloom,
although there may be individual coves where significant
mortality occurs as the fish become cut off from the main part
of the lake by the bloom. In a small pond or lagoon, however,
many or all of the fish present may be killed if a bloom is not
promptly treated and is allowed to spread across the entire
water body.
What are the ecological and economic impacts?
It is too early to tell at this time what the impacts may be in
Arizona. Potentially, the negative impacts may be significant
at a particular water, especially in larger lakes and reservoirs.
While golden alga toxins can affect all species and sizes of
fish, most of the fish killed at Saguaro, Canyon and Apache
lakes have been a 2-6 inch forage fish, threadfin shad. These
fish grow quickly and lay many eggs for rapid reproduction.
Because of this, a reservoir can recover, even from a massive
fish kill, if the waterbody has ample time between fish kills.
However, forage fish do form the basis of the food chain and
on-going fish kills may harm larger game fish in two ways,
directly by toxicity and indirectly by reduced food supply. Most
fish kills, however, do not continually affect the entire lake
and different parts of the lake may continue to support
excellent fishing.
Smaller, more intensely managed urban lakes can be treated
with chemical algaecides, and fish can be replaced by
5/1/12 Golden alga frequently asked questions
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restocking. To maintain their fish populations and control
golden alga, lake owners must increase their operating
budgets to cover costs associated with lake monitoring and
testing, algaecide treatments, and the purchase of
replacement fish.
Where else can I read about golden alga?
The Texas Parks and Wildlife Department provides information
on this problem to other agencies, universities and the public.
Their Web site, offers helpful information on golden alga and
other harmful algal blooms.
There is limited scientific information on basic ecology and
distribution of golden alga in inland waters of the United
States. So far, no one has found a practical way to stop
golden alga blooms and the fish kills they cause. Biologists
hope ongoing and future research, monitoring, teamwork and
collaboration will eventually find efficient solutions.
Does golden alga occur throughout the water column?
Golden alga can occur throughout the water column,
depending on the water’s depth. The cells need only
moderate light for photosynthesis, so they may be limited by
how deep the sunlight reaches. Generally, few golden alga
are found more than 20 feet below the lake surface.
However, some parts of the golden alga life cycle can occur in
the dark.
Resting cysts of golden alga (another stage in the life cycle)
sink to the bottom of the water column after formation. This
alga is different from other algae. Not only can it produce its
own food from photosynthesis, but by secreting its toxins it
can also capture, then eat and absorb other microscopic
organisms, primarily other species of planktonic algae and
bacteria, for sustenance.
Will warm water cause a golden alga bloom to
decrease?
Warmer waters may allow the algal community to change,
which can decrease a golden alga bloom. However, if golden
alga becomes numerous in the phytoplankton (algal)
community, it can last all year despite rising temperatures.
Fish kills due to golden alga have occurred in some Texas
lakes and rivers throughout the summer months. Worldwide
scientific literature states that golden alga is not toxic at 86
degrees Fahrenheit or above. Texas hatcheries have seen
decreases in golden alga numbers and impacts during the
heat of the Texas summer.
Most of the documented golden alga blooms and associated
fish kills occur during seasons when water temperatures are
between 55-80 degrees Fahrenheit. Winter conditions are
not favorable for other, common kinds of beneficial algae
normally found in our inland waters, which likely gives the
golden alga a competitive edge.
How do scientists measure the amount of golden alga
in the water?
Biologists collect water samples from various lake locations
and conduct cell counts to estimate how many golden alga
cells are in the water. Powerful microscopes are necessary to
identify this one-celled organism. A small amount of the water
sample is put on a specialized slide underneath a microscope
and then golden alga cells inside a grid are counted (each cell
is quite small).
Cell counts do not always correlate with toxicity, although
increased cell counts were found prior to the fish kills in
Texas. Golden alga can produce enough toxin to cause a fish
kill when cell concentrations are as low as 10,000
cells/milliliter, but fish losses in Texas typically have not
occurred until algal density was at 20,000 cells/milliliter or
more.
How do we get the answers we need?
The Arizona Game and Fish Department is working with
experts from the Texas Parks and Wildlife Department,
Arizona Department of Environmental Quality, Arizona
Department of Health Services, University of Arizona, and lake
management consultants to learn more about golden alga,
how to monitor it, and how to identify feasible options to
address it where possible.
Texas Parks and Wildlife Department (TPWD) has a Golden
Alga Task Force that is working with researchers, other
agency officials, and interested parties within and outside
Texas to research, monitor and control harmful golden alga in
Texas. In 2003, the Texas Legislature authorized the use of
$600,000 per year for two years for research on golden alga
in targeted areas. These areas include the development of
management tools, approaches and technologies to help
aquatic managers detect, combat, and manage golden alga in
Texas. Another $450,000 was dedicated for continued golden
alga research in 2005.
TPWD is also working on several other projects to better
understand and control golden alga. The solutions to the
problems of toxic golden alga (like other harmful algae
species) will not be solved easily or quickly, although
5/1/12 Golden alga frequently asked questions
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species) will not be solved easily or quickly, although
progress and successes will occur.
What is the Arizona Game and Fish Department doing
about golden alga?
The Arizona Game and Fish Department is working diligently
to learn more about this recently discovered alga in Arizona,
to inform the public, to monitor affected lakes, to investigate
all fish kills, and to work collaboratively with other affected
stakeholders. There is simply no "silver bullet" to eliminating
golden alga.
The Arizona Game and Fish Department has implemented
cooperative efforts that give Arizona the best chance to
mitigate the impacts of these events and address the
potential for future outbreaks. The department is coordinating
efforts to monitor fish kills and also to manage the
recreational fisheries in these waters with the lake
authorities and managers, state agencies, and other
stakeholders. These monitoring, management and research
efforts are significant and important.
The four lakes in the Salt River system (Saguaro, Canyon,
Apache, and Roosevelt) are being monitored regularly for
algal blooms and fish kills. The department has set up a
contact number (623-236-7257) for the public to report any
observations of golden alga blooms or fish kills. Fish kill and
other lake observation information suspected to be
connected with golden alga blooms may also be emailed to
the department at goldenalgae@azgfd.gov. The department
is also working with city officials to monitor, test and control
the golden alga at Urban Fishing Program lakes. The city park
departments have been responsive in treating their affected
lakes with algaecides. After each treatment is completed, the
department tests the lake waters to determine if the
treatment was successful in killing off the algae. When lake
water quality is satisfactory, fish stockings then resume.
When necessary, the lake will be restocked with sunfish, bass
and catfish. Public notices are posted around the Urban
Fishing Program lakes to advise park users of current
management and fish stocking activities.
Note: Although ponds and lakes smaller than a few hundred
surface acres can be treated successfully, these treatments
may not be economical or feasible in the larger and more
complex reservoirs and rivers.
Unfortunately, the golden alga situation is analogous to red
tides in coastal waters. Red tides are caused by different
toxic algae that also result in widespread fish kills. Extensive
research has been conducted on red tide algae in marine
environments for over 30 years that has increased
knowledge about the algae, but has not yet resulted in viable
treatments to control bloom outbreaks. The ultimate goal of
the department is to learn enough about golden alga to be
able to effectively manage it and its impacts. Until viable
management options are determined though, the
department’s emphasis remains on monitoring, management
and outreach about harmful golden alga blooms.
How can I help?
If you see dead or dying fish or large numbers of fish
behaving strangely, take note of the species and sizes of fish
affected, approximate numbers of fish observed, and the
location(s) where fish were observed. Report your
observations as soon as possible to the Arizona Game and
Fish Department at goldenalgae@azgfd.gov or call (623) 236-
7257. Common sense should be exercised by not picking up
dead or dying fish for consumption.
To prevent transporting the alga to other waters:
1. Drain all lake water from watercraft, live wells and
equipment before leaving the lake.
2. Rinse out watercraft, live wells and fishing equipment
at home and allow it to dry before using it at another
lake or river.
3. Do not move water, aquatic wildlife or plants (fish,
frogs, tadpoles, clams, crayfish, aquatic weeds, etc.)
offsite.
How can I learn about the most up-to-date
information?
Visit the Department Web site at www.azgfd.gov for current
information on golden alga and harmful algae blooms in
Arizona. You can also sign up to receive, via e-mail,
information directly from the department at
www.azgfd.gov/signup.
For more information on protecting our waters go to:
www.protectyourwaters.net.
Alga or Algae?
The term “alga” is used when only one species is being
referenced, such as Prymnesium parvum, the golden alga. If
the discussion is about several species (or a group of
species), then the term algae is used.
5/1/12 Golden alga frequently asked questions
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