skykeepers.org founded September 1, 1999
PAGE UNDER CONSTRUCTION JUNE 2008
This page
focused primarily on
the under addressed issue of light pollution and its effect on the
predation and development of Salmon at all life stages..
Research on this topic/page began with development of Light And The Environment pages of the IDA web site and further encouraged by the The resulting book Ecological Consequences of Artificial Night Lighting, By Catherine Rich & Travis Longcore (ECoANL)* serves as a reference for much of what we know about the effects of lighting and light pollution on the ecology. .
The intent here is to consolidate and link ECoANL and Internet resources which proved insight and evidence of the adverse effects of light pollution on the Salmon population of California and more specifically the Sacramento River System.
"Given the extensive knowledge of the role of light in structuring aquatic communities, marine and freshwater ecologist should consider the effects of artificial night lighting on these sensitive echosystems." * ECoANL Page 270
In this context "Light Pollution" refers to the sub category of Light Trespass and specifically Light Trespass on to and in to the aquatic environment.
Light at night should not be in any natural environment but when it must spectra, lighting levels, timing and environmental zone must be considered.
Page topics -
Related Local Pages-
An recent article notes the connection of Ammonia in the discharge of Sacramento's regional sewage treatment plant to the collapse of Delta fish populations. ( Ammonia from Sacramento waste ... Sacramento Bee June 1, 2008 see Recent Related News Stories ).
One problem that has not been taken seriously is the threat of Light Pollution. A more precise statement may be the threat of Light Trespass in to the water way (spawning beds and migration paths).
While Light Pollution (Light Trespass) may not be a prime contributing factor, it warrants consideration as on of the many factors.
As an example of a related issue see Sea lions along Sacramento River blamed for salmon decline, Sacramento Bee Jan. 2, 2009 see Recent Related News Stories
From the base of Shasta Dam to the San Francisco Bay a number of Light Pollution sources are obvious, may more may exist but these are some of the most obvious.
(1)
Sundial Bridge, Redding -
see Sundial Bridge a Threat to Salmon Population page for a closer look at the issue.
Although this bridge is a wonderful sight and it has been described as environmentally sensitive, it is not environmentally sensitive with respect to night lighting. Lighting under the bridge should be considered a serious environmental threat. In regards to Salmon, it is noted that the shadow of the bridge was designed to be very small to protect the Salmon spawning beds above and below the structure. Research shows that light on newly hatched Salmon causes vision problems and reduced survival rates and can have a adverse effect on developing fish eggs. Lighting of the bridge presents a possible predator trap for wild salmon smolts migrating from areas above the Bridge. It is also conceivable that could facilitate taking of adult Salmon at night, although much less likely than on lower portions of the river. Research relating to these issued are sighted and clipped below.
In all fairness it is noted that the lighting is not on all night. So it is just to bad for those Salmon who show up when the lights are on.
A page on this issue is under development, see Sundial Bridge a Threat to Salmon Population
Links -
, , ,
9/29/2004
, related -
Yes its beautiful at night and the day but what do the Salmon think? How would you like this above your babys crib every night?
Night Photo Links - , (Blog 13 Apr. 07), , ,
Related ECoANL *
* ECoANL Page 266 "Lights along a migratory watercourse may allowing increased predation by other vertebrate predators. Both inmigrating adult and out migrating juvenile salmon are captured by mammalian and avian predators, which can exert a significant pressure on depressed fish populations (Yurk and Trites 2000). "
* ECoANL Page 266 "Juvenile Pacific salmon begin downstream migration while their eyes are adapting to the dark (Brett and Ali 1958). This precess takes between 30 and 60 minutes depending on species and age, during which time individuals are unable to orient to fixed object and either swim with the current or are displace downstream (Ali 1995)."
* ECoANL Page 267 In a study of lighted and nonlighted areas along the Ceder Rive in Denton, Washington, Tabor et al.(2001) found increased nighttime lightning intensities to have a profound effect on sockeye (Oncorhyncbus nerka) fry. Increased nighttime light intensity, measured at lighted building and bridge sites, caused the fry to delay migration and move to the low velocity and lighted shoreline habitats. Downstream migration of sockeye fry each night was initiated after light intensity was less then 1 lux, a finding consistent with Ali's (1959) earlier research. When the light was artificially increased to 32 lux, however, migration almost completely stopped. "
Based on these and other references the lighted Sundial Bridge should be considered a significant barrier to downstream migration of wild salmon hatched above the bridge. Serious consideration of the effect of lighting on the spawning beds near the structure could not have possibly be considered. All this points to a serious flaw in the EIR process.
See: Impacts of Night Lighting, Predation & Light and Related News below
(2) Sacramento River Water Intake -
Lighting of the intake structure presents a predator trap for wild salmon smolts migrating from areas above the intake including the American River.
Lionakis Beaumont Design Group Inc. , Karen Bracamonte, Lionakis Beaumont Design Group Inc. in association with CH2MHill, City of Sacramento, EDAW, Montgomery Watson, and Balfor Beatty
Links Below see - "FISH HATCHERY OPERATION - Relating to Lighting",
Links - , ,
Photos - , ,
* ECoANL Page 265 "Minimal increases in lighting may thereby disrupt interactions between predator and prey species. Greater increases in illumination may allow normally diurnal predators to continue to forage at night perhaps even on normally diurnal prey species (Hobson 1995). Increased light also aids predatory fish or mammals attacking from below by allowing them to distinguish the dark form of their prey against an illuminated background (Hobson 1996)."
* ECoANL Page 266 "The observations at artificial lights are consistent with the history of research on natural illumination levels and predation risk (Woodhead 1966). Increased illumination is almost universally correlated with increased risk of predation for a species (Cerri 1983),..."
* ECoANL Page 263 "Nocturnal species respond to extremely low illumination levels: some species even exhibit negative phototaxis at illumination less than 10-2 lux (or .003fc) and forage at illumination as low as 10-5 lux(see Chapter 15, Table 15.1, this volume: Blaxter 1975a)"
Table 15.1 indicates that -
Pike, coho salmon, carp and minnow begin foraging for zooplankton at lux levels of 0.00001-0.01 or about 0.000001-0.001 fc.
Brown trout begin foraging for drifting stream insects at lux levels of 0.03-0.1 or about 0.003-0.01 fc.
See: Predation & Light and Related News below
(3) City of Sacramento Water Front -
The Sacramento Water Front , primarily on the Sacramento side of the river is a serious threat to migrating Salmon both smolt and adult. A obvious and now documented threat is created by the attraction of sea lions to the area and the no drought the taking during the night time hours.
See: "The salmon lovers return to Old Sac"(note "return"), "Electronic deterrent for hungry harbor seals", States seek permission to kill salmon-gobbling sea lions" and others below.
Links - ,
Photos - ,
* ECoANL Page 267 "Salmonids migrate from spawning areas through streams, rivers, and estuaries to the ocean, often moving at night. Retuning adult fish also migrate at night. Altered light environment along these routes may interrupt movement, increase predation on migrating fish, and ultimately reduce the number of successful migrants."
* ECoANL Page 266 "Lights along a migratory watercourse may allowing increased predation by other vertebrate predators. Both inmigrating adult and out migrating juvenile salmon are captured by mammalian and avian predators, which can exert a significant pressure on depressed fish populations (Yurk and Trites 2000). On the Puntledge River in British Columbia, Canada, lights from a bridge, halogen lights from a recreational field, and halogen lights from a sawmill facilitated foraging on outmigrating smolts by harbor seals (Phocavitulina: Yurk and Tites 2000). A "light-out" experimental treatment at the bridge reduced the number of seals feeding, but on subsequent nights the seals repositioned to exploit illumination form residual urban light."
See: Predation & Light and Related News below See also, "The salmon lovers return to Old Sac" below.
(4) Delta Docks -
Numerous lighted docks pose a danger from Sacramento through the delta and Carquinez Straits and out the Bay .
Recreational facilities as well as commercial facilities are a threat.
* ECoANL Page 265 "Prinslow et al. (1980) reported changes to fish assemblages and predation rates in a study of the effects of hight intensity security lights on a naval base in Puget Sound's Hood Canel. ... influence the behavior of fishes along the adjacent shoreline. ..."
* ECoANL Page 263 "Nocturnal species respond to extremely low illumination levels: some species even exhibit negative phototaxis at illumination less than 10-2 lux (or .003fc) and forage at illumination as low as 10-5 lux(see Chapter 15, Table 15.1, this volume: Blaxter 1975a)"
Table 15.1 indicates that -
Pike, coho salmon, carp and minnow begin foraging for zooplankton at lux levels of 0.00001-0.01 or about 0.000001-0.001 fc.
Brown trout begin foraging for drifting stream insects at lux levels of 0.03-0.1 or about 0.003-0.01 fc.
There are 11 Oil Terminals between the Golden Gate and the Sacramento River ; Port Richmond, Chevron Long Wharf Marine Terminal, Port of Benicia, Phillips 66, Shore Selby, Shell Martinez/Pacific Atlantic, Ultramar, Valero, Shore Martinez, Ultamar Avon, Condord Naval Wepons Station, and PG&E Pitsburg. Source State Lands Commission - , .
Much of the bay is illuminated unnaturally and the river is intermittently illuminated so with Feather River and Colusa more than 100 miles from the Golden Gate there is ample opportunities to have increased predation. It is about 350+ miles from the mouth in Suison Bay to Lake Shasta.
This statement may be ture but what about the night time environment "Low level lighting from marine terminals typically is distant from receptors and does not result in light and glare impacts to nearby land uses" what about the Scotobiological impacts on the aquatic environment?
See: Predation & Light and Related News below
(5) American River Water Intake -
See comments and links on (2) Sacramento River Water Intake
Related impacts of Night Lighting --
Cedar River Salmon Saved By Shielding Light Fixtures, WSDOT Northwest Region, Bulletin No. 01-12, March 23, 2001 (skykeeper snip)
"The Cedar River is where the largest run of sockeye salmon in the lower 48 states begins. Each year between January and June, several million salmon fry migrate from their spawning grounds east of Maple Valley to Lake Washington. The 2000 run was one of the biggest in recent memory, but the year before that was one of the worst, according to Roger Tabor, a fishery biologist with the U.S. Fish and Wildlife Service. Tabor has been working with federal, state, local and tribal governments to determine the reasons for the decline in the sockeye run. His research brought him to the Cedar River underneath I-405, where he noticed a problem. The lights that WSDOT installed to help keep trail users safe posed a threat to the sockeye salmon fry.
Light is basically a big stop sign,” Tabor said.
Sockeye like to migrate at night in the fastest part of the river channel and move to low velocity waters along riverbanks and river bottoms during the day. This way they avoid becoming the prey of fully-grown trout and sculpin, which like to forage at night. But the lights above the trail made the sockeye fry think it was daylight." ... Tabor estimated the lighting on the river resulted in several thousand salmon fry being eaten at this location in each spring migration period. ...
... After the first six shields were mounted ... The results were dramatic. Light readings showed that levels were similar to other nearby areas of the Cedar River that have no direct lighting. ...
The next evaluation was to see if the reduction in light led to a reduction in salmon fry on the riverbank. Again, the results were remarkable. ...
This account is referenced in * (ECoANL) Page 267-268 in regard to "Disruption of Migration" as follows -
"Recent research has documented adverse effect of artificial night lighting on the migratory behavior. In a study of lighted and nonlighted areas along the Ceder Rive in Denton, Washington, Tabor et al.(2001) found increased nighttime lightning intensities to have a profound effect on sockeye (Oncorhyncbus nerka) fry. Increased nighttime light intensity, measured at lighted building and bridge sites, caused the fry to delay migration and move to the low velocity and lighted shoreline habitats. Downstream migration of sockeye fry each night was initiated after light intensity was less then 1 lux, a finding consistent with Ali's (1959) earlier research. When the light was artificially increased to 32 lux, however, migration almost completely stopped. Similarly, Prinslow et al. (1980) previously showed that security lighting caused a delay in chum outmigrating through a canal. Tabor et al. (2001) also documented increased predation on migrating fry by sculpin under artificial lights."
...
LIGHT
Direct light may have an adverse effect on developing fish eggs. The most detrimental rays are those in the visible violet-blue range produced by cool white fluorescent tubes. Pink fluorescent tubes, which emit light in the yellow to red range, are best suited for hatchery use.
The best practice is to keep eggs covered and away from direct light. In general, embryos of fishes subjected to bright artificial light before the formation of eye pigments will suffer high mortality at all stages of growth.
Daily Temperature Units (D.T.U. = water temperature(F) minus 32 F). Walleye eggs start hatching approximately 14-18 days after spawning (300 DTU), depending on water temperature. Eggs and fry of walleye tolerate rapid temperature fluctuations. Approximately 390 daily temperature units are required for eggs to hatch in fluctuating water temperatures, while only 230 daily temperature units are required at more constant temperatures.
... ** Does this relate to the conditions under and around Sundial Bridge at Night. MH lamps under the bridge have more blue and UV than noted above.
"The amount and incidence of light received during incubation can affect both fish development and larval survival. Therefore, all types of egg incubating containers should be stored in such a manner to protect developing embryos from direct light."
** Does this relate to the conditions under and around Sundial Bridge at Night.
"The amount and incidence of light received during incubation can affect both fish development and larval survival. Incubation of fish embryos should occur in either dim light or darkness. Light can also be used to synchronize hatching. Many species of fish will not hatch in daylight, therefore, if the lights are switched off, hatching will occur a few hours later."
"The most important environmental factors affecting larval growth and survival are: (1) light, (2) temperature, and (3) salinity.
"Most salmonids exhibit light avoidance behaviors (Brookes 1988). Therefore, the removal of vegetation that decreases cover can limit the availability of preferred habitat for salmonids. To the extent that the removal of in-stream and streambank vegetation also reduces shading, water temperatures can be expected to increase. Changes in temperature can alter the rate of egg development, growth rates and rearing success, species competition, and community
composition (Beschta et al. 1987). "...
Notes on Fish Hatcheries --
A very interesting account of the history of the Coleman Fish Hatchery.
The Relationship of Predation and Light --
- "Seals wait in those shadows until they see juvenile salmon pass by in the lights overhead and then snatch them for a quick and frequent meal. The ease with which the seals are able to kill the salmon due to the lighting in that area are making it very difficult for the fish produced at the hatchery on the Puntledge River to make it out to sea."
"Dock lighting is also observed to induce temporary/localized delays by attracting fish, especially at nighttime. This is perhaps associated with prey attraction and/or visibility of prey." ... "Delayed migration of salmonids seems to happen when fish are confronted with conflicts regarding their preferences for eelgrass, dark areas, night lighting, or turbid zones."
With the exception of brief comments provided by Andrew Clarke of the Environment Agency, there appears to be little information regarding the potential effects of lighting on fish. Enquiries to clarify the lighting levels at which fish may be affected, have been
unsuccessful. The only practical comparator level is that produced by moonlight, which is generally accepted to be approximately 0.3-lux. However, it must be appreciated that this 0.3-lux level will be spread evenly over a large area of the river, and it is understood that problems arise where a bright band of light is present across a river, effectively forming a barrier through which fish may not pass. This is the typical effect produced by bridge mounted lighting, as demonstrated by the lighting design calculations. In order to minimize this effect, it will be necessary to restrict spill lighting to the bridge deck, by fitment of shields, or reduce the spill lighting levels on the river, to that produced by moonlight.
" In 1998, Stonehaven & District Angling Association secured a landmark UK court judgment on Light Nuisance (aka light pollution) which has attracted widespread interest from groups as diverse as biologists, civic societies, astronomers and others alarmed about the intrusive impact of ever-increasing artificial light sources on the natural environment and on the wellbeing of the individual. It is of particular importance to game anglers."
"This expert evidence revealed that seatrout, in common with most other nocturnal creatures, only night-adapt into an active roving and feeding role when natural light falls to between 0.5 and 0.2 Lux, owing "inter alia" to greater risk of predation at higher illuminance levels. There is also a concurrent switch from color (cone) vision to black-and-white (rod) vision. The importance of this low illuminance underlines the widely held opinion amongst experienced seatrout anglers, that an unshaded full moon (around 0.3 - 0.2 Lux) is highly ominous to fishing success."
- City of Bellevue WA search [Potential Impacts of Shoreline Development]
"Pier lighting may facilitate nocturnal predation on juvenile chinook and coho salmon by visual predators like smallmouth bass, cutthroat trout, and piscivorous
birds."
"Shoreline development could potentially increase the rate of predation on juvenile chinook by several principal means: ...
4) providing artificial lighting that allows for around-the-clock foraging by predators; "
"extending the duration of predation by allowing visual predators to forage at night (piers with artificial lighting)."
"Alteration (slowing) of migratory behavior and subsequent increased sculpin predation rates on sockeye fry with increasing light intensity were observed in simulated stream experiments (Tabor et al. 1998)."
"14. Artificial lighting retards migratory progress of sockeye fry, subjecting them to increased predation. Lights from industrial areas in south Lake Washington facilitate nocturnal foraging by piscivorous birds."
"13. Do not permit shoreline or pier lighting unless future studies suggest otherwise."
, WSDOT Web Site
WSDOT’s Ferry Division hopes to light the way for migrating salmon in Port Townsend. A new research project is taking place at the Port Townsend Ferry Terminal that will assess how migrating fish respond to artificial light.
Studies have shown that structures like ferry docks cast shadows over the waters near shore and affect the migration of juvenile fish. Because the small fish are used to bright water, they avoid the dark areas and maneuver around the structures, driving them into deeper water where they are more likely to become prey for other fish and birds.
To counter this effect, WSDOT, along with the University of Washington and the Pacific Northwest National Laboratory, are installing a fiber-optic lighting system under the Port Townsend Ferry Terminal to encourage fish to migrate under the structure. A solar power system above the terminal will run the lights during the day in an attempt to match sun levels in open water. ...
, Appendix B Page 5 October 2006
s, January 2006 Page 8
"Keeping the illuminated area and intensity of nighttime lighting to the minimum that is necessary for the intended purpose. Workers will direct lights onto the work areas and away from the water. "
See also, "The salmon lovers return to Old Sac" below.
It is apparent from a review of WSDOT and other Pacific Northwest resources that far more attention is paid to the relation of Salmon and local lighting conditions than is apparently exhibited in California.
Litigation --
Could the effects of Outdoor Lighting constitute a "taking" under the ESA?
Could a municipality or business along a water way fall under this act if it's docks, bridges and river front cast light onto the water?
If lighting increases predation of a listed species, then the municipality must be authorized accidental takes of the subject species.
"Harm" includes "significant habitat modification or degradation where it actually kills or injures wildlife by significantly impairing essential behavioral patterns, including breeding, feeding, or sheltering."
Altering the habitat in ways which allow or encourages increased predation by marine mammals constitutes a unauthorized taking.
Altering the habitat by introduction of artificial light removes or significantly impairs shelter or attracts fish into a unsafe area, enabling predation.
Research on this topic/page began with development of Light And The Environment pages of the IDA web site and further encouraged by the The resulting book Ecological Consequences of Artificial Night Lighting, By Catherine Rich & Travis Longcore (ECoANL)* serves as a reference for much of what we know about the effects of lighting and light pollution on the ecology. .
The intent here is to consolidate and link ECoANL and Internet resources which proved insight and evidence of the adverse effects of light pollution on the Salmon population of California and more specifically the Sacramento River System.
"Given the extensive knowledge of the role of light in structuring aquatic communities, marine and freshwater ecologist should consider the effects of artificial night lighting on these sensitive echosystems." * ECoANL Page 270
In this context "Light Pollution" refers to the sub category of Light Trespass and specifically Light Trespass on to and in to the aquatic environment.
Light at night should not be in any natural environment but when it must spectra, lighting levels, timing and environmental zone must be considered.
Page topics -
Vanishing Sacramento River Salmon - The
Threat of Light Pollution
Related Impacts of Night Lighting
Related Notes on Fish Hatcheries
The Relationship of Predation and Light
Litigation
Recent Related News Stories
Related Impacts of Night Lighting
Related Notes on Fish Hatcheries
The Relationship of Predation and Light
Litigation
Recent Related News Stories
Related Local Pages-
Ecological Light Pollution
(see Marine Life - Fish )
Light Pollution In The News (Media Coverage)
Pinniped Predation and Lighting (underdevelopment)
Light Pollution In The News (Media Coverage)
Pinniped Predation and Lighting (underdevelopment)
Vanishing
Sacramento River Salmon - The Threat of Light Pollution
Much has been
published recently sighting poor ocean
conditions and poor stewardship
of our watersheds as the caused of a drastic decline in Sacramento
River salmon. As a result officials are seeking
ways to
save every fish possible. An recent article notes the connection of Ammonia in the discharge of Sacramento's regional sewage treatment plant to the collapse of Delta fish populations. ( Ammonia from Sacramento waste ... Sacramento Bee June 1, 2008 see Recent Related News Stories ).
One problem that has not been taken seriously is the threat of Light Pollution. A more precise statement may be the threat of Light Trespass in to the water way (spawning beds and migration paths).
While Light Pollution (Light Trespass) may not be a prime contributing factor, it warrants consideration as on of the many factors.
As an example of a related issue see Sea lions along Sacramento River blamed for salmon decline, Sacramento Bee Jan. 2, 2009 see Recent Related News Stories
From the base of Shasta Dam to the San Francisco Bay a number of Light Pollution sources are obvious, may more may exist but these are some of the most obvious.
(Creative Commons) |
(2) Sacramento Water Intake by |
 (3) Sacramento Water Front iStockphoto.com: Royalty-free |
 (4) Delta Docks |
(5) City water intake American River |
see Sundial Bridge a Threat to Salmon Population page for a closer look at the issue.
Although this bridge is a wonderful sight and it has been described as environmentally sensitive, it is not environmentally sensitive with respect to night lighting. Lighting under the bridge should be considered a serious environmental threat. In regards to Salmon, it is noted that the shadow of the bridge was designed to be very small to protect the Salmon spawning beds above and below the structure. Research shows that light on newly hatched Salmon causes vision problems and reduced survival rates and can have a adverse effect on developing fish eggs. Lighting of the bridge presents a possible predator trap for wild salmon smolts migrating from areas above the Bridge. It is also conceivable that could facilitate taking of adult Salmon at night, although much less likely than on lower portions of the river. Research relating to these issued are sighted and clipped below.
In all fairness it is noted that the lighting is not on all night. So it is just to bad for those Salmon who show up when the lights are on.
A page on this issue is under development, see Sundial Bridge a Threat to Salmon Population
Links -
, , ,
9/29/2004
, related -
Yes its beautiful at night and the day but what do the Salmon think? How would you like this above your babys crib every night?
Night Photo Links - , (Blog 13 Apr. 07), , ,
Related ECoANL *
* ECoANL Page 266 "Lights along a migratory watercourse may allowing increased predation by other vertebrate predators. Both inmigrating adult and out migrating juvenile salmon are captured by mammalian and avian predators, which can exert a significant pressure on depressed fish populations (Yurk and Trites 2000). "
* ECoANL Page 266 "Juvenile Pacific salmon begin downstream migration while their eyes are adapting to the dark (Brett and Ali 1958). This precess takes between 30 and 60 minutes depending on species and age, during which time individuals are unable to orient to fixed object and either swim with the current or are displace downstream (Ali 1995)."
* ECoANL Page 267 In a study of lighted and nonlighted areas along the Ceder Rive in Denton, Washington, Tabor et al.(2001) found increased nighttime lightning intensities to have a profound effect on sockeye (Oncorhyncbus nerka) fry. Increased nighttime light intensity, measured at lighted building and bridge sites, caused the fry to delay migration and move to the low velocity and lighted shoreline habitats. Downstream migration of sockeye fry each night was initiated after light intensity was less then 1 lux, a finding consistent with Ali's (1959) earlier research. When the light was artificially increased to 32 lux, however, migration almost completely stopped. "
Based on these and other references the lighted Sundial Bridge should be considered a significant barrier to downstream migration of wild salmon hatched above the bridge. Serious consideration of the effect of lighting on the spawning beds near the structure could not have possibly be considered. All this points to a serious flaw in the EIR process.
See: Impacts of Night Lighting, Predation & Light and Related News below
(2) Sacramento River Water Intake -
Lighting of the intake structure presents a predator trap for wild salmon smolts migrating from areas above the intake including the American River.
Lionakis Beaumont Design Group Inc. , Karen Bracamonte, Lionakis Beaumont Design Group Inc. in association with CH2MHill, City of Sacramento, EDAW, Montgomery Watson, and Balfor Beatty
Links Below see - "FISH HATCHERY OPERATION - Relating to Lighting",
Links - , ,
Photos - , ,
* ECoANL Page 265 "Minimal increases in lighting may thereby disrupt interactions between predator and prey species. Greater increases in illumination may allow normally diurnal predators to continue to forage at night perhaps even on normally diurnal prey species (Hobson 1995). Increased light also aids predatory fish or mammals attacking from below by allowing them to distinguish the dark form of their prey against an illuminated background (Hobson 1996)."
* ECoANL Page 266 "The observations at artificial lights are consistent with the history of research on natural illumination levels and predation risk (Woodhead 1966). Increased illumination is almost universally correlated with increased risk of predation for a species (Cerri 1983),..."
* ECoANL Page 263 "Nocturnal species respond to extremely low illumination levels: some species even exhibit negative phototaxis at illumination less than 10-2 lux (or .003fc) and forage at illumination as low as 10-5 lux(see Chapter 15, Table 15.1, this volume: Blaxter 1975a)"
Table 15.1 indicates that -
Pike, coho salmon, carp and minnow begin foraging for zooplankton at lux levels of 0.00001-0.01 or about 0.000001-0.001 fc.
Brown trout begin foraging for drifting stream insects at lux levels of 0.03-0.1 or about 0.003-0.01 fc.
See: Predation & Light and Related News below
(3) City of Sacramento Water Front -
The Sacramento Water Front , primarily on the Sacramento side of the river is a serious threat to migrating Salmon both smolt and adult. A obvious and now documented threat is created by the attraction of sea lions to the area and the no drought the taking during the night time hours.
See: "The salmon lovers return to Old Sac"(note "return"), "Electronic deterrent for hungry harbor seals", States seek permission to kill salmon-gobbling sea lions" and others below.
Links - ,
Photos - ,
* ECoANL Page 267 "Salmonids migrate from spawning areas through streams, rivers, and estuaries to the ocean, often moving at night. Retuning adult fish also migrate at night. Altered light environment along these routes may interrupt movement, increase predation on migrating fish, and ultimately reduce the number of successful migrants."
* ECoANL Page 266 "Lights along a migratory watercourse may allowing increased predation by other vertebrate predators. Both inmigrating adult and out migrating juvenile salmon are captured by mammalian and avian predators, which can exert a significant pressure on depressed fish populations (Yurk and Trites 2000). On the Puntledge River in British Columbia, Canada, lights from a bridge, halogen lights from a recreational field, and halogen lights from a sawmill facilitated foraging on outmigrating smolts by harbor seals (Phocavitulina: Yurk and Tites 2000). A "light-out" experimental treatment at the bridge reduced the number of seals feeding, but on subsequent nights the seals repositioned to exploit illumination form residual urban light."
See: Predation & Light and Related News below See also, "The salmon lovers return to Old Sac" below.
(4) Delta Docks -
Numerous lighted docks pose a danger from Sacramento through the delta and Carquinez Straits and out the Bay .
Recreational facilities as well as commercial facilities are a threat.
* ECoANL Page 265 "Prinslow et al. (1980) reported changes to fish assemblages and predation rates in a study of the effects of hight intensity security lights on a naval base in Puget Sound's Hood Canel. ... influence the behavior of fishes along the adjacent shoreline. ..."
* ECoANL Page 263 "Nocturnal species respond to extremely low illumination levels: some species even exhibit negative phototaxis at illumination less than 10-2 lux (or .003fc) and forage at illumination as low as 10-5 lux(see Chapter 15, Table 15.1, this volume: Blaxter 1975a)"
Table 15.1 indicates that -
Pike, coho salmon, carp and minnow begin foraging for zooplankton at lux levels of 0.00001-0.01 or about 0.000001-0.001 fc.
Brown trout begin foraging for drifting stream insects at lux levels of 0.03-0.1 or about 0.003-0.01 fc.
There are 11 Oil Terminals between the Golden Gate and the Sacramento River ; Port Richmond, Chevron Long Wharf Marine Terminal, Port of Benicia, Phillips 66, Shore Selby, Shell Martinez/Pacific Atlantic, Ultramar, Valero, Shore Martinez, Ultamar Avon, Condord Naval Wepons Station, and PG&E Pitsburg. Source State Lands Commission - , .
Much of the bay is illuminated unnaturally and the river is intermittently illuminated so with Feather River and Colusa more than 100 miles from the Golden Gate there is ample opportunities to have increased predation. It is about 350+ miles from the mouth in Suison Bay to Lake Shasta.
This statement may be ture but what about the night time environment "Low level lighting from marine terminals typically is distant from receptors and does not result in light and glare impacts to nearby land uses" what about the Scotobiological impacts on the aquatic environment?
See: Predation & Light and Related News below
(5) American River Water Intake -
See comments and links on (2) Sacramento River Water Intake
Related impacts of Night Lighting --
Cedar River Salmon Saved By Shielding Light Fixtures, WSDOT Northwest Region, Bulletin No. 01-12, March 23, 2001 (skykeeper snip)
"The Cedar River is where the largest run of sockeye salmon in the lower 48 states begins. Each year between January and June, several million salmon fry migrate from their spawning grounds east of Maple Valley to Lake Washington. The 2000 run was one of the biggest in recent memory, but the year before that was one of the worst, according to Roger Tabor, a fishery biologist with the U.S. Fish and Wildlife Service. Tabor has been working with federal, state, local and tribal governments to determine the reasons for the decline in the sockeye run. His research brought him to the Cedar River underneath I-405, where he noticed a problem. The lights that WSDOT installed to help keep trail users safe posed a threat to the sockeye salmon fry.
Light is basically a big stop sign,” Tabor said.
Sockeye like to migrate at night in the fastest part of the river channel and move to low velocity waters along riverbanks and river bottoms during the day. This way they avoid becoming the prey of fully-grown trout and sculpin, which like to forage at night. But the lights above the trail made the sockeye fry think it was daylight." ... Tabor estimated the lighting on the river resulted in several thousand salmon fry being eaten at this location in each spring migration period. ...
... After the first six shields were mounted ... The results were dramatic. Light readings showed that levels were similar to other nearby areas of the Cedar River that have no direct lighting. ...
The next evaluation was to see if the reduction in light led to a reduction in salmon fry on the riverbank. Again, the results were remarkable. ...
This account is referenced in * (ECoANL) Page 267-268 in regard to "Disruption of Migration" as follows -
"Recent research has documented adverse effect of artificial night lighting on the migratory behavior. In a study of lighted and nonlighted areas along the Ceder Rive in Denton, Washington, Tabor et al.(2001) found increased nighttime lightning intensities to have a profound effect on sockeye (Oncorhyncbus nerka) fry. Increased nighttime light intensity, measured at lighted building and bridge sites, caused the fry to delay migration and move to the low velocity and lighted shoreline habitats. Downstream migration of sockeye fry each night was initiated after light intensity was less then 1 lux, a finding consistent with Ali's (1959) earlier research. When the light was artificially increased to 32 lux, however, migration almost completely stopped. Similarly, Prinslow et al. (1980) previously showed that security lighting caused a delay in chum outmigrating through a canal. Tabor et al. (2001) also documented increased predation on migrating fry by sculpin under artificial lights."
...
LIGHT
Direct light may have an adverse effect on developing fish eggs. The most detrimental rays are those in the visible violet-blue range produced by cool white fluorescent tubes. Pink fluorescent tubes, which emit light in the yellow to red range, are best suited for hatchery use.
The best practice is to keep eggs covered and away from direct light. In general, embryos of fishes subjected to bright artificial light before the formation of eye pigments will suffer high mortality at all stages of growth.
Daily Temperature Units (D.T.U. = water temperature(F) minus 32 F). Walleye eggs start hatching approximately 14-18 days after spawning (300 DTU), depending on water temperature. Eggs and fry of walleye tolerate rapid temperature fluctuations. Approximately 390 daily temperature units are required for eggs to hatch in fluctuating water temperatures, while only 230 daily temperature units are required at more constant temperatures.
... ** Does this relate to the conditions under and around Sundial Bridge at Night. MH lamps under the bridge have more blue and UV than noted above.
"The amount and incidence of light received during incubation can affect both fish development and larval survival. Therefore, all types of egg incubating containers should be stored in such a manner to protect developing embryos from direct light."
** Does this relate to the conditions under and around Sundial Bridge at Night.
"The amount and incidence of light received during incubation can affect both fish development and larval survival. Incubation of fish embryos should occur in either dim light or darkness. Light can also be used to synchronize hatching. Many species of fish will not hatch in daylight, therefore, if the lights are switched off, hatching will occur a few hours later."
"The most important environmental factors affecting larval growth and survival are: (1) light, (2) temperature, and (3) salinity.
(1) Light. The effect of light intensity and photoperiod on the growth and survival of larvae has received little attention in the past. Generally, fish larvae are reared either under continuous light or under day and night conditions. The few data accumulated to date show contradictory results. Rearing larvae under continuous light conditions has a positive effect on growth and survival for some species, but not for others.
It has been shown that high light intensities are detrimental particularly to the newly-hatched larvae. Light intensity must thus be controlled to optimize growth and survival. Young first feeding marine fish larvae have a feeding threshold of only 10 to 10 metre candle. Light intensities of 10 to 10 metre candle provide optimum feeding conditions." ** no idea what "10 to 10 metre candle" is, the point is high light intensities can be detrimental.
(.pdf) , WSDOT, 2005-06-10"Most salmonids exhibit light avoidance behaviors (Brookes 1988). Therefore, the removal of vegetation that decreases cover can limit the availability of preferred habitat for salmonids. To the extent that the removal of in-stream and streambank vegetation also reduces shading, water temperatures can be expected to increase. Changes in temperature can alter the rate of egg development, growth rates and rearing success, species competition, and community
composition (Beschta et al. 1987). "...
Notes on Fish Hatcheries --
A very interesting account of the history of the Coleman Fish Hatchery.
The Relationship of Predation and Light --
- "Seals wait in those shadows until they see juvenile salmon pass by in the lights overhead and then snatch them for a quick and frequent meal. The ease with which the seals are able to kill the salmon due to the lighting in that area are making it very difficult for the fish produced at the hatchery on the Puntledge River to make it out to sea."
"Dock lighting is also observed to induce temporary/localized delays by attracting fish, especially at nighttime. This is perhaps associated with prey attraction and/or visibility of prey." ... "Delayed migration of salmonids seems to happen when fish are confronted with conflicts regarding their preferences for eelgrass, dark areas, night lighting, or turbid zones."
With the exception of brief comments provided by Andrew Clarke of the Environment Agency, there appears to be little information regarding the potential effects of lighting on fish. Enquiries to clarify the lighting levels at which fish may be affected, have been
unsuccessful. The only practical comparator level is that produced by moonlight, which is generally accepted to be approximately 0.3-lux. However, it must be appreciated that this 0.3-lux level will be spread evenly over a large area of the river, and it is understood that problems arise where a bright band of light is present across a river, effectively forming a barrier through which fish may not pass. This is the typical effect produced by bridge mounted lighting, as demonstrated by the lighting design calculations. In order to minimize this effect, it will be necessary to restrict spill lighting to the bridge deck, by fitment of shields, or reduce the spill lighting levels on the river, to that produced by moonlight.
" In 1998, Stonehaven & District Angling Association secured a landmark UK court judgment on Light Nuisance (aka light pollution) which has attracted widespread interest from groups as diverse as biologists, civic societies, astronomers and others alarmed about the intrusive impact of ever-increasing artificial light sources on the natural environment and on the wellbeing of the individual. It is of particular importance to game anglers."
"This expert evidence revealed that seatrout, in common with most other nocturnal creatures, only night-adapt into an active roving and feeding role when natural light falls to between 0.5 and 0.2 Lux, owing "inter alia" to greater risk of predation at higher illuminance levels. There is also a concurrent switch from color (cone) vision to black-and-white (rod) vision. The importance of this low illuminance underlines the widely held opinion amongst experienced seatrout anglers, that an unshaded full moon (around 0.3 - 0.2 Lux) is highly ominous to fishing success."
- City of Bellevue WA search [Potential Impacts of Shoreline Development]
"Pier lighting may facilitate nocturnal predation on juvenile chinook and coho salmon by visual predators like smallmouth bass, cutthroat trout, and piscivorous
birds."
"Shoreline development could potentially increase the rate of predation on juvenile chinook by several principal means: ...
4) providing artificial lighting that allows for around-the-clock foraging by predators; "
"extending the duration of predation by allowing visual predators to forage at night (piers with artificial lighting)."
"Alteration (slowing) of migratory behavior and subsequent increased sculpin predation rates on sockeye fry with increasing light intensity were observed in simulated stream experiments (Tabor et al. 1998)."
"14. Artificial lighting retards migratory progress of sockeye fry, subjecting them to increased predation. Lights from industrial areas in south Lake Washington facilitate nocturnal foraging by piscivorous birds."
"13. Do not permit shoreline or pier lighting unless future studies suggest otherwise."
, WSDOT Web Site
WSDOT’s Ferry Division hopes to light the way for migrating salmon in Port Townsend. A new research project is taking place at the Port Townsend Ferry Terminal that will assess how migrating fish respond to artificial light.
Studies have shown that structures like ferry docks cast shadows over the waters near shore and affect the migration of juvenile fish. Because the small fish are used to bright water, they avoid the dark areas and maneuver around the structures, driving them into deeper water where they are more likely to become prey for other fish and birds.
To counter this effect, WSDOT, along with the University of Washington and the Pacific Northwest National Laboratory, are installing a fiber-optic lighting system under the Port Townsend Ferry Terminal to encourage fish to migrate under the structure. A solar power system above the terminal will run the lights during the day in an attempt to match sun levels in open water. ...
, Appendix B Page 5 October 2006
s, January 2006 Page 8
"Keeping the illuminated area and intensity of nighttime lighting to the minimum that is necessary for the intended purpose. Workers will direct lights onto the work areas and away from the water. "
See also, "The salmon lovers return to Old Sac" below.
It is apparent from a review of WSDOT and other Pacific Northwest resources that far more attention is paid to the relation of Salmon and local lighting conditions than is apparently exhibited in California.
Litigation --
Could the effects of Outdoor Lighting constitute a "taking" under the ESA?
The answer
is, without question YES!
see the following
Loggerhead Turtle v. County Council of Volusia County, Florida, 148 F.3d 1231 (11th Cir. 1998).
Loggerhead Turtle v. County Council of Volusia County, Florida, 896 F. Supp. 1170 (M.D. Fla. 1995).
see the following
Loggerhead Turtle v. County Council of Volusia County, Florida, 148 F.3d 1231 (11th Cir. 1998).
Loggerhead Turtle v. County Council of Volusia County, Florida, 896 F. Supp. 1170 (M.D. Fla. 1995).
Could a municipality or business along a water way fall under this act if it's docks, bridges and river front cast light onto the water?
If lighting increases predation of a listed species, then the municipality must be authorized accidental takes of the subject species.
"Harm" includes "significant habitat modification or degradation where it actually kills or injures wildlife by significantly impairing essential behavioral patterns, including breeding, feeding, or sheltering."
Altering the habitat in ways which allow or encourages increased predation by marine mammals constitutes a unauthorized taking.
Altering the habitat by introduction of artificial light removes or significantly impairs shelter or attracts fish into a unsafe area, enabling predation.
Recent Related News Stories -
, By Matt Weiser mweiser@sacbee.com Published: Friday, Jan. 09, 2009 | Page 14A
Salmon, steelhead and sturgeon in the Central Valley are being driven to extinction by Delta pumping systems and upstream reservoir operations, according to a draft federal report.
The National Marine Fisheries Service has not yet released the report, but it was discussed at a meeting of scientists in Sacramento on Thursday. ...
When these gates are open, young salmon migrating to sea stray into waters teeming with predators, including foreign species such as striped bass.
Federal biologist Jeff Stuart said closing the gates almost doubles salmon survival rates.
Other threats include herbicides to control aquatic weeds, entrapment in the suction effect of the water diversion pumps, and rough handling at fish screens near the pumps. ... No mention of Lighting in amonge the "Other threats".
By Matt Weiser - mweiser@sacbee.com, Published: Friday, Jan. 02, 2009 | Page 10A
Ask a Sacramento angler for reasons why Central Valley salmon populations have crashed over the past two years, and this is likely to be high on the list:
"Dozens of sea lions that live between Rio Vista and Verona year-round," said Sacramento fisherman Terry Horst. "That's a major problem because they eat tons of fish a day."
Scientific brain power has been applied in thick doses to many aspects of the alarming fish declines in the Sacramento-San Joaquin Delta – from weather patterns to water pollution. No one with a science degree, however, has had anything to say about sea lions. ...
Now Mark Dendy, a professor of biology and natural resources at American River College, has produced a survey of the Delta sea lion population. And, yes, there are resident sea lions, though not nearly as many as fishermen think.
According to Dendy, five individual California sea lions live most of the year in the Sacramento River. They account for most sightings between Isleton and Colusa.
These five spend much of their time in the river near downtown Sacramento, at the confluence with the American River. Dendy has seen them eating catfish and striped bass. But their favorite appears to be chinook salmon – as many as one every 45 minutes. see The salmon lovers return to Old Sac
Really is this some new revelation. This has been know for some time and as pointed out (links on this page) the Columbia River problem is old news. The same is true of how casting light at night on to the water enables additional (24hour) predation by Brutus the sea lion and others.
See Dave Bitts: A fisherman’s view of the salmon crisis, 'Optics' preventing B.C. seal cull, States Seek Permission to Kill Salmon-Gobbling Sea Lions
See also
See also
, By Matt Weiser, Sacramento Bee, Published: Friday, Jan. 02, 2009, The Fresno Bee
- By Matt Weiser, Sacramento Bee, Published 12:00 am PDT Thursday, August 7, 2008
Story appeared in MAIN NEWS section, Page A7
California forestry officials Wednesday rejected an emergency petition to protect coho salmon in coastal streams, even though federal fisheries regulators said it would help the imperiled fish.
The petition before the state Board of Forestry comes as California salmon are at historic lows, requiring regulators to suspend all salmon fishing on the coast this year – a first.
, By Matt Weiser, Sacramento Bee, Published 12:00 am PDT Sunday, June 1, 2008
After years of searching high and low for a culprit in the collapse of Delta fish populations, scientists are learning the problem may lie right under their noses.
The likely fish killer is ammonia, a common byproduct of human urine and feces.
Sacramento's regional sewage treatment plant is the largest single source of ammonia in the Delta. It discharges treated wastewater from nearly 1.4 million people into the Sacramento River near Freeport – without removing ammonia. ...
, By Matt Weiser, Sacramento Bee, Published 12:00 am PDT Thursday, May 1, 2008
The Sacramento Valley is a well-used landscape. After 160 years of mining and urbanizing, plowing and diverting, you'd think the environment would have given up all its secrets.
But a trio of local scientists recently unlocked a mystery about why young salmon grow faster during floods in the Yolo Bypass, and in the process they identified a new species. ...
"They grew like gangbusters, often twice as fast as fish that stayed out in the river," ...
Hydrobaenus saetheri is a newly discovered species of tiny fly, or midge, now known to be a major food source for young salmon when water floods the Yolo Bypass.
, By Dave Bitts - Special to The Bee, Published 12:00 am PDT Monday, April 28, 2008
... "We've abused our
rivers to the point that the fish are on the verge of permanently
vanishing." ...
The Sacramento River system once yielded 2 million Chinook salmon a year. This year, with no fishing, 60,000 adults are expected to return. Wild salmon populations likewise are in dire straits in the Klamath and the Columbia-Snake river systems. The West Coast was once home to the most productive watersheds in the world, with these three river systems producing between 13 million and 19 million salmon a year.
... "If we can't learn to coexist
with salmon, are any wild creatures safe from us?" ...
**
Mr. Bitts
makes some very good points. However stewardship of the
watersheds rightfully should include the threat of light pollution and
its resulting "taking" of adult and juvenile salmon .
, By Matt Weiser - mweiser(@)sacbee.com, Published 12:00 am PDT Friday, April 25, 2008
... Federal officials will also truck about 10 percent of the salmon produced at their hatchery near Redding. They haven't trucked fish in more than a decade, and then only as a test. This year, those fish will ride nearly 200 miles to reach San Pablo Bay. ...
The fall-run chinook population is expected to hit a record low this year for reasons that remain unclear. Commercial and recreational ocean fishing have been closed for the first time in history, and river fishing is likely to be closed next month. ...
Research has shown that trucking hatchery salmon doubles or triples their odds of reaching the ocean by avoiding threats along the way, said Alice Low, an environmental scientist at the state Department of Fish and Game. ...
** Wild salmon, fish from Colman Hatcheries (Redding) and the Feather River hatchery face some what more threat than Nimbus Fish Hatchery on the American River. The greatest threat from light pollution, for all salmon begins at the confluence of the Sacramento and America Rivers.
NOTE map at the end of this story.
Sea lions to lose easy pickings at dam, by Michael Milstein, The Oregonian Published: Friday, April 25, 2008
PORTLAND -- The on-again, off-again permission for Oregon and Washington officials to kill salmon-gobbling sea lions below Bonneville Dam is off again, courtesy of a federal appeals court injunction issued this week.
However, the appeals court said state officials could still capture sea lions and ship them to zoos. Oregon officials said they would begin trapping up to eight of the Bonneville animals Thursday.
The sea lions gather at Bonneville Dam on the Columbia River to feast on salmon, including imperilled species, gathering to climb the dam's fish ladder. Frustrated fishermen and biologists fear the animals' appetite is cutting into billion-dollar efforts to restore Northwest salmon.
Roughly 25 to 30 sea lions have stationed themselves at the dam, but as many as 60 -- a record -- gathered there a few weeks ago, said Brian Gorman of the National Marine Fisheries Service. He said the sea lions eat a total of 50 to 100 adult chinook salmon a day. ...
, By M.S. Enkoji - menkoji@sacbee.com Published 12:00 am PDT Sunday, April 20, 2008
... Last year was the second-lowest spawning season on record along the Sacramento River and its tributaries. Just 90,000 chinook returned from the sea to complete their life cycle in the freshwater – a 90 percent drop from five years earlier. ...
,
Canwest News Service, Published: Sunday, April 20, 2008
... Even under perfect conditions, only one per cent of Chinook salmon
smolts that swim down the Puntledge and into the Strait of Georgia
return three or four years later to spawn.
The presence of crafty, voracious harbour seals makes their chances of
survival even worse.
According
to Ottawa, a herd of determined seals has been trolling the Puntledge
for years, eating up almost every baby summer Chinook in sight.
Some
50 seals have learned to swim up the Puntledge and hide in the shadows
under a bridge that serves the city of Courtenay. Streetlights that
line the city's Fifth Street bridge illuminate the unsuspecting smolts
as they move downstream at night; the seals set their sights, open
their mouths and feast. ...
, Harbour seals
devouring salmon, Hational Post , By Brian
Hutchinson, Published: Saturday, April 19, 2008COURTENAY,
B.C. -'I am not bloodthirsty," swears Larry Peterson, a
retired schoolteacher, sport fisherman and self-described ecologist. He
does not specifically loathe seals. But he knows that his promotion of
a West Coast seal slaughter might seem "insensitive," at best. ...
Harbour seals are swimming amok in the Puntledge, once famous for its runs of large salmon. Smaller cousins of the commercially harvested harp seals in the Atlantic, they are clever, highly adaptable creatures that have discovered how to make easy pickings of salmon fry and adult, spawning salmon. ...
... Even under perfect conditions, only 1% of Chinook salmon smolts that swim down the Puntledge and into the Strait of Georgia return three or four years later to spawn. ...
Some 50 seals have learned to swim up the Puntledge and hide in the shadows under a bridge that serves the city of Courtenay. Streetlights that line the city's Fifth Street bridge illuminate the unsuspecting smolts as they move downstream at night; the seals set their sights, open their mouths and feast.
"I've seen eight seals make almost a straight line across the river and slurp up the fish," says Mr. Peterson, who is chairman of the Puntledge River Restoration Committee and a member of several other volunteer ecological and conservation groups. ...
Next week, a private company based in Washington State
will dispatch
a team to Courtenay. Workers will lay an array of electrified cables in
the Puntledge, under the Fifth Street bridge.
Once switched on,
the cables will emit a low voltage charge into the water; it is hoped
that the "mild, underwater electric field" will keep hungry harbour
seals at bay and deter them from swimming upstream. ...
, By Matt Weiser - mweiser@sacbee.com, Published 12:00 am PDT Wednesday, April 16, 2008
... Fish and Game officials on Tuesday reluctantly voted to shelter a diminished population of Sacramento River chinook by barring all ocean salmon fishing in state waters, out three miles from shore. The unprecedented closure will last through April 2009. The move follows last week's ban on salmon fishing in the 200-mile swath of federal water off California and Oregon. ...
Biologists say closures are needed to protect the region's fall-run chinook, the backbone of the Pacific Coast's salmon fishery. These fish account for as much as 80 percent of salmon caught in California and Oregon. "That's one of the most painful votes I think we've ever taken," said Richard Rogers, president of the California Fish and Game Commission, of Tuesday's historic vote. This year the species' population is predicted to hit a historic low – just 58,200 are expected to spawn in the Sacramento, American, Feather and other rivers. That's down from 775,000 in 2002. ...
Fishery experts believe poor ocean conditions in 2005,
possibly
caused by global warming, eliminated much of the food supply for young
salmon entering the ocean that year. Those fish became the 2008
spawners.
Other factors have not been ruled out, including poor habitat and food
supply in rivers and the Sacramento-San Joaquin Delta. ...
** fact is
** NOTE
If you've been hanging around Old Sac these days, that barking you hear isn't the coyotes fighting for a piece of the nearby downtown railyard.
Nope, it's a pack of vocal sea lions – a rookery, if you will, because apparently I'm obsessed with collective animal nouns.
About this time each year, the marine mammals travel to our bend in the river in pursuit of the savory salmon run, conveniently congregating near the Delta King. Manager Mike Coyne says it makes for a pretty spectacular spectacle for paddleboat passengers.
"What's kind of fun is when they're right off the boat and they're fishing," he said.
In case you didn't know, the difference between sea lions and seals is all in the ears – as in, sea lions have them and seals don't.
As for what they end up deciding about that railyard, we're all, all ears.
** What Lisa and others don't understand is that the lighting around the Delta King and Docks are why the salmon are easy picking for the sea lions. It is wall documented that predation increases in areas with lighting along rivers during salmon runs and during out migration.
We in this quote form Page 266 provide just one documented example.
"Lights along a migratory watercourse may allow increased predation by other vertebrate predators.
Both inmigrating adult and outmigrating juvenile salmon are captured by mammalian and avian predators, which can exert a significant pressure on depressed fish populations (Yurk and Trites 2000). On the Puntledge River in British Columbia, Canada, lights from a bridge, halogen lights from a recreational field, and halogen lights from a sawmill facilitated foraging on outmigrating smolts by harbor seals (Phoca vitulina; Yurk and Trites 2000).
A "lights-out" experimental treatment at the bridge reduced the number of seals feeding, but on subsequent nights the seals repositioned to exploit illumination from residual urban light."
Search note [seals salmon preditation +lighting +bridge] [seals salmon predation +lighting +bridge]
, By Less Blumenthal, McClatchy Newspapers 4/15/07
... Prior to the passage of the Marine Mammal Protection Act in 1972, California sea lions were rarely sighted in the 140-mile stretch of river between the Pacific Ocean and Bonneville Dam, the first of the 19 huge hydroelectric dams on the mainstream of the Columbia and its largest tributary, the Snake River. The numbers of California sea lions had dwindled to fewer than 10,000 before Congress acted. Until 1972, Washington and Oregon paid bounties for sea lions killed in the Columbia, and a state-sanctioned hunter was employed. Now, an estimated 300,000 California sea lions inhabit the Pacific, breeding on the islands off Southern California and chasing the food supply as far north as Puget Sound. ...
... Once, an estimated 16 million salmon returned annually to the Columbia and its tributaries. Now, 13 salmon and steelhead species are protected under the Endangered Species Act. "There is not a lot of room for error," Norman said of the effort to revive the most endangered runs.
, Posted on: Sunday, 15 April 2007, 00:00 CDT
WASHINGTON _ For three years, the California sea lions dining on endangered salmon below Bonneville Dam on the Columbia River have been blasted with rubber buckshot, chased by boats, harassed by firecrackers and rockets and subjected to irritating acoustic frequencies blaring from underwater speakers.
More Links (Web Masters Notes, Place Holders, etc.) -
Echolocical Light Pollution - skykeepers.org
zooplankton
- We investigated also the effect of light on the carnivorous feeding of both pelagic and littoral mysids. Highest feeding rate of pelagic mysids was observed in total darkness but littoral mysids were not affected by light at all. This may be explained by different habitats and the prevailing light conditions in these environments. Pelagic mysids are used to migrate to deep water when light increases to avoid fish predation, thus they are not used to feed in light. In the littoral zone, on the other hand, mysids are used to bright light and their feeding is not hampered by it ().
It has been shown that freshwater pelagic mysid shrimps capture zooplankton at a higher rate in light than in darkness. ... The feeding rates of pelagic mysids were significantly higher in total darkness than in light. In contrast, the feeding rates of littoral mysids did not differ in the dark and the light in the three different seasons. ...
* (ECoANL) Ecological Consequences of Artificial Night Lighting, By Catherine Rich & Travis Longcore
Chapter 11 Artificial Night Lighting and Fishes
Contributors Barbara Nightingale, Travis Longcore and Charles A. Simenstad
.
Page created June 2008
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