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Environmental Consequences, Cumulative Impacts (2002 - 2006), and Mitigation Measures

Figure 5.2.2.2-2. Estimated dispersion of drilling

mud that remains in the water column for

drilling at the Gato Canyon Unit site. The Santa

Ynez Unit platforms are also shown. Ellipses are

approximately 7 km long and 3 km wide.

Figure 5.2.2.2-3. Estimated dispersion of drilling

mud that remains in the water column for

drilling at the Bonito Unit site. The Point

Arguello Unit platforms are also shown. Ellipses

are approximately 7 km long and 3 km wide.

Figure 5.2.2.2-4. Estimated dispersion of drilling

mud that remains in the water column for

drilling at the Point Sal and Purisima Point Unit

drilling sites. Ellipses are approximately 7 km

long and 4 km wide.

5.2.3 IMPACTS ON ROCKY AND SANDY

BEACH HABITAT

This section discussed impacts from the proposed

project on biological resources found on rocky and

sandy intertidal beaches.

5.2.3.1 IMPACTS OF THE PROPOSED

PROJECT ON ROCKY AND SANDY

BEACH HABITAT

Criteria used here and in Chapter 6 to assess

impacts to these resources are:

HIGH

Impacts that result in a measurable decline in a

population beyond that which can be explained by

normal variability, result in a measurable change regionally in species composition, ecological function or

community structure, or result in a measurable reduction in regionally important habitat are considered to be high impacts. These changes would be at

a level, areal extent and duration that would be expected to place an individual species at risk, or alter

the community structure or habitat on a regional scale

for many years. Irreversible alteration of regionally

important habitat or reduction of protected habitat

would be considered high impacts.

MODERATE

Impacts that result in a measurable decline in

species composition, species abundance, ecological

function or community structure over several local-
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Delineation Drilling Activities Offshore Santa Barbara County

ized areas or result in alteration of locally important

habitat are considered moderate impacts. These

changes, while individually may persist for many years,

are localized and cannot be detected on a population

or regional level.

LOW

Impacts that result in a short-term change in

species abundance or composition, a temporary loss

in ecological function or community structure, a shortterm disturbance or temporary loss of access to locally important habitat are considered to be low impacts.

In this document, high and moderate impacts are

considered significant; low impacts are considered to

be insignificant.

5.2.3.1.1 IMPACTS COMMON TO ALL UNITS

There are no identified impacts to rocky or sandy beaches

from the Proposed Action.

5.2.3.2 CUMULATIVE IMPACT ANALYSIS

FOR ROCKY AND SANDY BEACH

HABITAT

5.2.3.2.1 CUMULATIVE IMPACTS (2002-2006)

The Cumulative Description Section describes the

projects considered in the cumulative analysis for

the proposed exploration activities. Possible sources

of cumulative impacts in the project area include

ongoing and proposed oil and gas activities in

Federal and State waters, Alaskan and foreign

import tankering, and military operations. Cumulative impacts to rocky and sandy beaches can also

occur due to public use (collecting, fishing, and

trampling), pollution events from surface runoff and

sewage spills, and natural occurrences such as

extreme storm events, increased ocean water temperature and spreading of disease.

Cumulative Impacts Without the Proposed

Action (2002-2006): Since there are no impacts from

the Proposed Action on rocky or sandy beach resources, no analysis of cumulative impacts is appropriate here. However, impacts to this resource could

occur if development of the 36 undeveloped leases occurs. These impacts are discussed in Chapter 6.

5.2.4 IMPACTS ON SEAFLOOR RESOURCES

This section discusses impacts from the proposed

projects on biological resources found on the ocean

floor, exclusive of kelp beds.

5.2.4.1 IMPACTS OF THE PROPOSED ACTION

ON SEAFLOOR RESOURCES

Criteria used to assess impacts to these resources

here, and in chapter 6, are as follows:

HIGH

Impacts that result in a measurable decline in a

population beyond that which can be explained by normal variability, result in a measurable change regionally in species composition, ecological function or community structure, or result in a measurable reduction

in regionally important habitat are considered to be

high impacts. These changes would be at a level,

areal extent, and duration that it would be expected to

place an individual species at risk, or alter the community structure or habitat on a regional scale for

many years. Irreversible alteration of regionally important habitat or reduction of protected habitat would

be considered high impacts.

MODERATE

Impacts that result in a measurable decline in

species composition, species abundance, ecological function or community structure over several localized

areas or result in alteration of locally important habitat are considered moderate impacts. These changes,

while individually may persist for many years, are localized and cannot be detected on a population or regional level.

LOW

Impacts that result in a short-term change in

species abundance or composition, a temporary loss in

ecological function or community structure, a shortterm disturbance or temporary loss of access to locally

important habitat are considered to be low impacts.

In this document, high and moderate impacts are

considered significant; low impacts are considered to

be insignificant.

Impacts Common to All Units: Impacting agents

from the proposed action, described below, would not

affect resources in the shallow subtidal zones. Therefore, this discussion will only include discussion of

impacts on offshore benthic resources. Impacting

agents that could affect benthic resources include the

drilling of holes into the substrate, placing the drill
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Environmental Consequences, Cumulative Impacts (2002 - 2006), and Mitigation Measures

plate on the ocean floor, discharging drilling muds and

cuttings, placing anchors, retrieving anchors, and removing the drill plate. Impacts from these activities

include direct smothering, increased turbidity, physical disturbance, and elevated levels of metals on the

ocean surface and in the water column.

Physical Disturbances. Physical disturbances

associated with the projects include the placement and

removal of the drill plate, the physical drilling of a

hole in the substrate, and placement and removal of

anchors and associated chains. Physical disturbances

on soft bottom habitat are predicted to cause only temporary changes in species abundance or composition,

insignificantly impacting soft bottom benthos. Softbottom infauna is expected to rapidly repopulate or

recolonize, and changes are expected to be well within

natural variability for the resource. In general, the

constant sediment movement on soft bottom surfaces

overwhelms the physical disturbances caused by these

activities.

Physical disturbances on hard bottom substrate,

however, can cause moderate impacts. If disturbances

occur in relatively undisturbed or high relief hard bottom habitat, impacts could include changes in species

composition and community structure by altering the

natural composition of the substrate, i.e. breaking the

larger rocks into smaller pieces which could be recolonized by different species. Anchors and their chains,

if placed in high relief hard bottom habitat, can crush

or smother long-lived animals over the localized area

contacted. In 1995, a study was completed which conducted field investigations of OCS wells to document

the extent of physical damage by anchoring operations

and quantify the recovery time from these types of disturbances (MEC, 1995). After review of 60 wellsite

locations near potential hard substrate, 9 were identified which appeared to disturb hard bottom communities. Investigation of these nine wellsites found disturbances at four wellsites. Conclusions from the

study are as follows:

1) The primary impact is the physical alteration

of the substrate size and the amount of exposed

hard substrate. Hard bottom communities will

not recover to pre-disturbed conditions where

substrate has been altered, and instead a different type of hard substrate community will

develop.

2) Depending on the size and frequency of the disturbance, hard bottom communities can recover. Deeper water communities are slower

to recover than communities found in shallower water.

3) Recovery takes years to decades depending on

the complexity of the community, high relief

communities being the most complex.

4) Since exploratory anchoring activities are infrequent and impact less than 1% of hard bottom habitat within a given mooring system,

this level of disturbance does not represent a

threat to the maintenance of a diverse and abundant epifaunal community.

5) There was no evidence for the persistence of

drilling muds or cuttings near wellsites investigated in the study.

6) Impacts are more pronounced in areas of high

percentages of hard substrate because the anchors reduce the size of the rocks and alter the

available habitat for high relief species.

7) Anchor impacts in areas of low percentage of

hard substrate were actually found to increase

the amount of hard substrate habitat by uncovering the veneer over the rocks and by piling the rock in higher berms.

Discharges — Soft Substrate Habitat. The contribution of muds and cuttings to the soft bottom

benthic environment is not expected to significantly

alter the natural habitat or cause population level

changes in abundance or composition of species. Impact on this resource from drilling mud and cuttings

discharges primarily due to localized smothering and

alteration of sediment grain size over a localized area,

a low impact.

Due to the cutting’s larger grain size, the cuttings fall close around the wellsite. The muds, a very

small grain size, tend to be carried in the water column and dispersed further from the wells, at distances

up to 6 km (Battelle, 1991) (see the Water Quality

Impact Section). Phase II of the California Monitoring Program (Battelle, 1991) monitored the drilling

from Platforms Hidalgo, Hermosa and Harvest from

1986 to 1989, when a total of 39 wells were drilled.

Phase III of CAMP (SAIC and MEC, 1995) continued

to monitor potential effects on the benthic communities for an additional six years to look for sublethal

effects. Extensive chemistry sampling, detailed soil

analysis, and intensive biological monitoring enabled

researchers to detect trace levels of metals and hydrocarbons and low levels of biological change. Conclusions from Phase II and III (Battelle, 1991; and SAIC

and MEC, 1995) are as follows:

1) The concentrations of metals generally reflected

average concentrations in crustal rocks and their origin is believed to be the deeper formations drilled by

the wells.

2) The concentration of petroleum hydrocarbons

in the surficial sediments and water column

was occasionally elevated. Because the patterns did not match drilling activity levels or
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Delineation Drilling Activities Offshore Santa Barbara County

location, the investigators concluded that these

random increases were influenced by natural

tar seeps, rather than drilling activities.

3) With the exception of barium, none of the metals was elevated in concentration in the sediments during the drilling period, and only

barium and zinc were higher in the drilling

muds than in surface sediments

4) Within one and a half years after cessation of

drilling, barium levels reached background in

the sediment traps, but were still slightly elevated in the surface sediments.

Any biological effects due to the drilling muds

were related to physical effects of smothering, not

chemical toxicities, and are limited to within one km

of the discharge source (Battelle, 1991). Based on these

findings above for drilling 39 wells over a concentrated

area, impact to soft bottom habitat overall from drilling the 5 delineation wells is expected to be low. Low

impacts could occur under the wellsites due to changes

in sediment grain size and the resultant changes in

species composition.

Discharges — Hard Substrate Habitat. Impacts

from drilling mud discharges from five delineation wells

are expected to be low. Impacts from drill cutting discharges from the five delineation wells range from low

to moderate, depending on the location of the wellsites

in relation to high relief habitat, and mitigation applied. Several of the potential wellsite locations are

proposed near potential hard substrate habitat. If biological surveys of canyons and potential outcrop features identify important high relief habitat within

325m (1000 feet) of the wellsite, discharges of cuttings

from drilling without mitigation may result in moderate impacts.

Potential effects of drilling muds and cuttings

on hard substrate communities offshore California

were discussed in “Review of Recovery and

Recolonization of Hard Substrate Communities of the

Outer Continental Shelf” (Lissner et al, 1987). The

study was funded by MMS in response to questions

asked by agencies, fishermen and scientists interested

in these hard bottom biological communities. While

much of this study addressed anchoring impacts, the

study did discuss sedimentation impacts on hard substrate communities. Lissner et al. (1987) point out

that the natural sediment movements overwhelm the

sediment changes documented from drilling mud discharges. Natural movements of large quantities of

bottom sediments periodically covering and uncovering broad low relief hard substrates have been documented off Florida and Oregon and are believed to be

consistent with patterns observed offshore California.

Strong bottom currents known to exist, and observations of sediment movement are consistent with this

theory. Inputs from the projects drilling muds and

cuttings are of shorter duration comparatively and

much more localized in effect (Lissner et al., 1987; Neff,

1987).

Direct smothering and turbidity can adversely

affect filter-feeding organisms such as the sponges, cup

corals, and anemones found on naturally occurring

hard bottom reefs. Because habitat supporting these

animals occurs within the immediate vicinity of the

Point Arguello platforms and pipelines, intensive monitoring was conducted during drilling activities at the

three Point Arguello platforms from 1986 to 1995.

Conclusions from Phase II and III that pertain to hard

substrate habitats are as follows:

1) Four of 22 taxa displayed significant time/dose

interactions representing possible negative responses to the drilling mud discharges in specific habitat. These taxa were sabellids in deep

low-relief habitat, Caryophyllia sp(p) in deep

low relief and deep high-relief habitat, galatheid

crabs in deep low-relief habitat, and

Halocynthis hilgendorfi igborja in deep lowrelief habitat. Combined trends for the various taxa were not statistically significant.

 2) It was concluded that any biological effects

due to the drilling muds were related to physical effects of the increased particle loading,

not chemical toxicities.

3) Adverse biological effects on the benthos from

this study, as in other documented studies, were

limited to within one km of the discharge

source.

Impacts Unique to Each Unit: Impacts to hard

substrate communities are dependent on the location

of wellsites and anchors to hard bottom substrate.

Point Sal Unit. In the Operator’s project description, Aera states that well locations have been

chosen to be at least 325 m (1,000 feet) from mapped

outcrops, anchor activities will follow a Project Anchoring Plan, and hard bottom substrate will be

avoided.

The operator’s preferred wellsite is OCS-P 0416

#3 (Figure 5.2.4-1). While the wellsite is located 92 m

(300 feet) from a small identified hard bottom feature,

the feature has little or no relief and it is not believed

to contain hard bottom communities. The lack of exposed hard bottom was corroborated by the lack of

rockfish fishing in the area of the feature (pers. comm.,

S.Timoschuk). Impacts from this wellsite would be

low. Another possible wellsite location is along the

southern border of OCS-P 0422 (Figure SF 1). This

site is located sufficiently distant from identified outcrop that it is unlikely that anchors would reach potential habitat. The third location, P 0421 #1, is located 325 meters (1000 feet) from a potential exposed
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Environmental Consequences, Cumulative Impacts (2002 - 2006), and Mitigation Measures

rocky outcrop mapped at the border between Lease

OCS-P 0421 and P 0422. Longline rockfish fishermen

identify this feature as a habitat for rockfish (pers.

comm., S. Timoschuk), which provides further indication that this is exposed hard substrate habitat. As

proposed, it is expected that physical disturbance from

drilling cuttings should not adversely impact hard

substrate communities, but drilling muds could cause

increased turbidity and potentially affect the community. Currents in the area would tend to move mud

toward the hard bottom feature. While the volume of

mud released from drilling one well is low, it is estimated that impacts could range from low to moderate,

based on the proximity of the wellsite to the feature

and prevailing currents.

The proximity of the wellsite to this long feature

makes anchoring without impacting the feature difficult. It would appear that anchors or their chains

would unavoidably impact the feature at the current

location. Impacts from more than one anchoring event

across the hard bottom are considered a moderate

impact, since without additional data, it is assumed

that the feature contains high relief communities. The

duration and severity of impact would depend on the

number of anchors impacting the feature and the complexity of the biological community found on it.

The Biological Lease Stipulation has been invoked on P 0421 and P 0422, requiring the operator

to either avoid impact to the identified rocky outcrop,

or conduct a biological survey of the feature.

Purisima Point Unit Description. The above

measures for the Point Sal Unit were also provided by

Aera in the Project Description for Purisima Point.

One isolated feature has been mapped in the center of

lease on Lease OCS-P 0426 (Figure 5.2.4-1). While

the size of the feature is small, shallow hazards data

indicates sufficient relief to support hard substrate

communities. Fishermen confirmation of this feature

as good rockfish habitat (pers. comm., S. Timoschuk)

lends further support that it contains exposed habitat. Both preferred proposed wellsite locations for this

Unit are located within 1,000 meters of this feature.

If biological surveys confirm the presence of hard substrate communities, both drilling muds and anchors

could impact these communities from the drilling of

either well. This would be considered a moderate impact. The duration and severity of impact would depend on the number of anchors impacting the feature

and the complexity of the biological community found

on it. The biological lease stipulation has been invoked on lease P 0426.

Bonito Unit Description. The primary area of

interest in this unit is presence of deep canyons. One

small and four large canyons traverse the Bonito Unit

(Figure 5.2.4-2). Shallow hazards review confirms the

presence of very steep slopes and potential outcrop

areas in each canyon, particularly on the southern

wall. In general, outcrop areas are more likely to be

located along the steepest portions of the canyon wall,

and along the crest of the canyon, though fishermen

information indicate that exposed habitat is present

on the sides and at the bottom of the canyon (pers.

comm. S. Timoschuk). The priority wellsite, P 0446

#5, is sufficiently distant from canyon features that

well drilling activities, with the possible exception of

a long anchor, would not be expected to impact hard

bottom resources. The remaining three proposed

wellsite locations are located proximal to the same

canyon and would likely to cause moderate impacts as

presently proposed. These include OCS-P 0500 #2,

located 1200 m (4,000 feet) from the edge of the canyon, OCS-P 0443 #3, located 365 m (1200 feet) from

the southern wall of the canyon; and OCS-P 0443 #4,

located approximately 457 m (1500 feet) from the southern wall of the canyon.

Figure 5.2.4-1. Identified hard bottom in the Point

Sal and Purisima Point Units

Figure 5.2.4-2. Identified canyons and hard

bottom in the Bonito Unit.
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Delineation Drilling Activities Offshore Santa Barbara County

Prevailing currents would tend to move muds

and cuttings from the wellsites on P 0443 in a northwest direction toward the canyon. However, because

the volume of muds released during the drilling of one

well is small, impacts from mud discharges are expected to be low to moderate. Prevailing currents

would tend to move the muds and cuttings from the

wellsite on P 0500 into the canyon further to the north,

rather than to the canyon located just south of the

wellsite. The distance from P 0500 #2 to the northern canyon is further and impacts on hard bottom

habitat from muds and cuttings discharges would,

therefore, be expected to be low and less than that

from the other two locations on P 0443. The biological stipulation has been invoked requiring avoidance

or conduct of a biological survey. Extent of impact

and duration of recovery from disturbance will depend

on the complexity of the resources that have the potential to be impacted. In general, a well drilled at

any location within anchor reach of a canyon would

be expected to cause moderate impacts to resident

benthic populations. The biological lease stipulation

has been invoked on all leases in the Bonito Unit due

to the presence of steep sloped canyons throughout

the area.

Gato Canyon Unit. Samedan has restated that

they are committed to the mitigation measures detailed

in the original Exploration Plan for this lease and to

the measures dictated by MMS in the original Letter

of Approval. These measures include:

—Anchoring activities will be conducted in accordance with a project anchoring plan.

—Anchors will be placed and removed vertically

to minimize impact on seabed organisms.

—Anchors and anchor chains will avoid hard

bottom substrate to reduce potential to impact sensitive hard bottom habitat.

—Well location will avoid known outcrops by at

least 1,000 meters.

Impacts from this project have been assessed

assuming these measures are in place.

The wellsite OCS-P 0460 #3 is located approximately 6.5 km (4 miles) offshore El Capitan in 230 m

(755 feet) of water, just shy of 1,000 m from the nearest potential hard bottom habitat (Figure 5.2.4-3). This

wellsite has been set back to the west and south of

their preferred location in order to respond to MMS

concerns about anchoring into the potential hard substrate community located on the northern half of the

lease. The current wellsite is located optimally to reduce anchor length while keeping the wellsite the

maximum distance from identified hard substrate.

When drilling a previous well on P 0460, though

the anchors to the north were specifically shortened

to avoid hard bottom, piggybacking of one anchor was

required to maintain stability. This resulted in an

anchor extending into the potential hard bottom habitat. To anticipate and prevent this same situation from

reoccurring, Samedan specifically moved the proposed

wellsite to the west and south so that even piggybacked

anchors would avoid the identified potential hard bottom habitat. Based on Samedan’s proposed avoidance

measures evident in the measures taken to locate the

well, impacts to the resource from this delineation well

as proposed are expected to be low. The biological

stipulation has been invoked on this lease due to the

presence of potential hard bottom communities on the

lease.

5.2.4.1.1 SUMMARY AND CONCLUSION

Physical impacts to hard bottom seafloor resources, due to the potential to impact stable hard

bottom communities with anchors and chains, are

moderate for all projects except for the Gato Canyon

Unit project, which is low. Impacts from all projects

combined are also expected to be moderate. Both the

drilling of individual wells with multiple anchoring

events, and the drilling of several wells with multiple

anchoring events near sensitive hard substrate habitat is likely to result in long-term impacts to plants

and animals, and alter habitat in several localized areas, a moderate impact.

Due to the comparatively low volume of mud discharged during the drilling of delineation wells, the

water depth of proposed wellsites, and proximity of

wellsites to identified hard substrate, impacts on seafloor resources from drilling discharges are expected

to be low to moderate. Wellsites located a distance of

1,000 m from identified hard bottom substrate would

introduce low impacts to seafloor resources. Discharges from wellsites located within 1,000 m could

produce moderate impacts to hard bottom habitat due

Figure 5.2.4-3. Identified hard bottom in the Gato to smothering, depending on the actual distance from

Canyon Unit.
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Environmental Consequences, Cumulative Impacts (2002 - 2006), and Mitigation Measures

the feature, predominate currents and quality of the

habitat on the feature.

Overall impacts on seafloor resources from the

proposed delineation wells combined are moderate, due

to the potential to impact hard bottom communities.

5.2.4.1.2 MITIGATION MEASURES FOR

IMPACTS FROM THE PROPOSED

ACTION

The Biological Lease Stipulation, which has been

specifically invoked on those leases where hard bottom habitat is believed to exist, provides the legal framework for mitigating impacts to sensitive biological resources. In the past where MMS has invoked the stipulation and carried out its provisions through avoidance and appropriate mitigation, the stipulation has

been shown to be highly successful in reducing impacts to hard bottom communities (MEC, 1995). The

primary mitigation for physical impacts from the delineation drilling is avoidance. Wellsites can be moved

so that they do not come in contact with hard bottom

habitat and avoid all potential impacts to this community from well placement. Anchors can also be positioned specifically to avoid impacting potential or identified hard substrate habitat with either the anchors

or chains. Avoidance, monitoring, and other measures

are identified to reduce impacts from drilling discharges.

Mitigation SF1—Move Wellsite off Features. To

avoid physical disturbance from the hole and drill plate,

move wellsite at least 92 m (300 feet) from identified

hard bottom substrate. This placement is verified in

the plan and as inspected in the field during placement by MMS inspectors. This mitigation is not needed

at this time, as no proposed wellsites are currently

located on a feature. This mitigation may be used in

the future if wellsite relocations are needed for other

environmental or technical reasons.

Mitigation SF2—Anchor Handling and Avoidance. Avoid impacts from anchors and chains. Require an anchoring plan that identifies specifically, based

on the MODU, the proposed anchor locations by

wellsite. This plan should clearly demonstrate avoidance to identified hard bottom habitat with a buffer

dictated by the precision of the data. The plan should

also detail anchor handling procedures with an anchor handling boat, use of a vertical retrieval system

and a weather shut down plan to ensure anchors are

not placed during inclement weather and do not drag

on the seafloor at any time. Require operator to meet

with MODU personnel to familiarize them with the

plans. MMS would inspect the operations in the field

to ensure the plan is followed and any variances in

the field are approved prior to placement.

Mitigation SF3—Wellsite Relocation. To avoid

potential smothering impacts from drill cuttings and

muds on hard bottom habitat, move wellsite locations

at least 1000 m (3280 feet) away from identified hard

bottom habitat.

Mitigation SF 4—Wellsite Relocation and Monitoring. To avoid potential impacts from drill cuttings,

move wellsites locations at least 300m (984 feet) from

habitat. If within 1000 m (3280 feet) of the habitat, to

avoid impacts from drill muds, establish an ongoing

discharge monitoring program which permits discharge only when currents are moving away from the

identified biological communities. Current meters need

to be placed at the site so that current direction at the

discharge point is known. Shunting of discharges away

from identified communities may also be considered,

in addition to monitoring at the surface, if the predominant current regime tends to move mud toward

features. Mitigate on a case-by-case basis as needed

to ensure that significant smothering impacts are not

occurring on identified hard bottom habitat features.

Mitigation SF 5—Zero Discharge. To avoid potential impacts from drilling muds and cuttings on the

identified habitat, require a zero discharge of muds

and cuttings within 1,000 m (3280 feet). Discharges

may either be placed downhole, shunted outside a 1,000

m (3280 feet) distance from the habitat, barged to

shore (covered in Alternative 2), or a combination of

these measures to accomplish the objective.

Site-Specific Mitigation. The following measures

would be needed to reduce identified moderate impacts

to low impacts for each wellsite, assuming biological

surveys confirm the presence of hard bottom habitat.

Point Sal Unit. OCS-P 0421 #1: The wellsite

will likely need to be moved so that anchoring on the

feature is avoided (SF 3). It seems unlikely that the

operator would be able to successfully mitigate anchor

placement at its present location. If the anchoring

issue is resolved and the well is left at its current location, the operator would need to actively monitor discharges and mitigate their project based on the monitoring program (SF 4), or not discharge (SF 5). To

fully mitigate drilling mud discharges, the wellsite

would need to be located 1,000 m from the feature (SF

3); or have a zero discharge (SF 5). If future well

relocations to address safety or geologic concerns move

the wellsite inside 300 m (984 feet), the operator would

need to have a zero discharge (SF 5) to avoid moderate impacts from cuttings.

Plan revisions would need to be specifically reviewed for all wells in the plan, once the MODU is

known, to ensure that anchors avoid placement on

identified rocky features. Such review cannot be conducted at this time due to lack of site-specific rig information.
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Delineation Drilling Activities Offshore Santa Barbara County

Purisima Point Unit. OCS-P 0426 #1, #2:

The Anchor Handling and Avoidance Mitigation (SF

2) would be needed to reduce physical impacts to low.

Either SF 3, SF 4, or SF 5 would be needed to ensure

that smothering effects from drilling discharges were

reduced to low for wellsite #2.

Bonito Unit. OCS-P 0500 #2: Mitigations SF 2

and SF 3 would need to be adopted to avoid impact to

potential resources from wellsite P 0443 #3, and 4

and P 0500 #2. Mitigation SF 2 would need to be

adopted to ensure that anchoring activities from P

0446 #5 avoided impacting potential resources in the

canyon.

5.2.4.2 CUMULATIVE IMPACTS ANALYSIS

FOR SEAFLOOR RESOURCES

5.2.4.2.1 CUMULATIVE IMPACTS (2002-2006)

The cumulative introduction section describes the

projects considered in the cumulative analysis for the

proposed delineation activities. Cumulative impacts

to seafloor resources may occur from commercial fishing operations, fiber cable installation operations,

ongoing and reasonably foreseeable oil and gas activities in Federal and State waters and non-anthropogenic and anthropogenic sources of sediment and contaminants.

Cumulative Impacts Without the Proposed

Action (2002-2006): The projects discussed in this

section include past, present, and foreseeable actions

that may produce impacts during 2002-2006, the expected duration of the proposed delineation activities.

Discharges. A natural source of sedimentation

is the turbidity current or flow. This sediment-laden,

density-driven current “avalanches” along the seafloor bringing pulses of sediment from the continental

shelf toward deep water (see Water Quality section

“resuspension processes”.) These flows are the most

pronounced during onshore flooding years in which

large amounts of sediment are discharged into the

marine environment by rivers, creeks and storm drains.

The largest volume of sediment recorded occurred in

1969 following extreme flooding events (Kolpack and

Drake, 1985). In contrast, sediment input to the environment from drilling muds and cuttings is periodic,

localized, and of substantially less volume overall.

Natural sediment flows and resuspension processes

overwhelm the turbidity plumes from past or ongoing

oil and gas drilling activities in the Basin or Channel

both in terms of volume of sediment and areal extent

of affect (Drake, Kolpack, and Fischer, 1972)

Anthropogenic sources of pollution that may affect seafloor resources in the area of the proposed

projects, especially biota closer to shore, include point

source discharges (sewage outfalls), dredging activities, surface runoff, thermal discharges (nuclear generating stations) and the Guadalupe oil field “spill”.

Future projects in the area include dredging at Boathouse at the southern edge of Vandenburg Air Force.

Hydrocarbons from seepage from onshore tanks in the

Guadalupe oil field was detected offshore in the CAMP

study (SAIC and MEC, 1995). The dredging activity

would have localized turbidity impacts and is unlikely

to overlap with resources affected by the proposed

projects. Overall impacts from these anthropogenic

sources of pollution are difficult to quantify, but they

are expected to create increased turbidity, increased

uptake of heavy metals, oils and potentially toxic substances by the biota. These impacts would be expected

to be highest nearshore, near sources of pollution.

These impacts range from low to moderate on the resource.

Physical Disturbances. Bottom Trawling Activities. The activity which has the highest potential to

directly impact seafloor resources in proximity to the

delineation wellsites during the period between 2002

and 2006 are the past, present and future bottom trawling commercial fishing activities. Bottom trawling for

halibut and other groundfish occurs in the upper portion of the Santa Maria Basin along the eastern portions of Purisima Point and Point Sal Units, and rockfish trawling occurs in deeper waters in the Bonito

Unit and in State waters near Point Conception (see

Commercial Fishing section). Rockfish trawling also

occurs near the State line and across the Gato Canyon Unit. Primary activity for trawling associated

with groundfish fisheries such as halibut would be

expected to occur to soft bottom habitat. However,

rockfish trawling activities primarily affects hard bottom habitats. The use of roller gear off the Pacific

coast, while reducing impacts from otter door troughs

to the seafloor, has permitted fishing in formerly inaccessible rocky areas (NMFS, 1998).

Impacts from bottom trawling fishing activities

in the Santa Maria Basin and Santa Barbara Channel

range from low to high. In the soft bottom environment, troughs made by trawling gear create short-term

depressions in sandy sediments, or may create troughs

lasting months to years in clay or mud sediments.

Biological effects on the soft bottom habitat, however,

would be considered low from groundfish fishing due

to the level of activity in the Santa Maria Basin/western Santa Barbara Channel, and the fact that the community would be expected to recolonize within a relatively short period of time. However, habitat alteration of higher relief rocky reefs could create moderate to high impacts depending on the amount and extent to which complex communities have and continue

to be altered. Fishing gear impacts the biological seafloor resources by removing marine plants, corals and

sessile organisms, upending rocks, leveling rock for-
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mations, re-suspending sediments (NMFS, 1998).

These impacts irreversibly alter the marine habitat

complexity. Since there is no restriction about the

location that this fishing can occur, outside the

fishermen’s own concern for hanging up their equipment on the higher relief rocks, it is speculated that

much of the hard bottom habitat in the area has been

altered. In the absence of reliable field data, residual

impacts are assumed to range from low to high, depending on the areal extent of impact and the overall

impact on the population. NMFS views the impact to

occur on a region wide basis, indicating a possible high

impact. They conclude that:

“...there are few, if any, large virgin marine habitats off the Pacific Coast. Due to the high relief rocky

nature of Pacific coast bottom habitat, however, there

may be pockets of habitat that have undergone few

alterations by trawl gear. High relief rock piles that

are not accessible to trawl gear are usually accessible

to commercial longline and recreational hook-and-line

gear. Similarly, marine canyons that have not been

trawled may be used by commercial longliners.”

Existing Oil and Gas Activities. While there are

several cumulative oil and gas projects that could occur during the time when delineation wells are being

drilled, these activities do not overlap in space with

the proposed projects. There is no ongoing oil and

gas activity located close enough to the proposed

wellsites to create impacts that overlap directly with

the resources potentially impacted by the proposed

projects.

Previous exploratory wells drilled in the 1980’s

on the same leases where delineation wells are proposed may have physically impacted seafloor resources.

Residual impacts from these wells, however, would be

low. If anchoring occurred in clay sediments, it is

possible that some anchor scars still persist on these

leases (Dunaway and Schroeder, 1989); however, impacts to the soft bottom resources would not have persisted since recolonization would have occurred a short

time after the disturbance (camp). A total of ten wells

have been drilled in the proposed units historically

which could have impacted rocky habitat—six wells

in the Bonito Unit, one well in Gato Canyon, two wells

in the Point Sal Unit, and one well in the Purisima

Point Unit. Anchoring impacts could have impacted

rocky habitat; however, mitigation imposed on these

wells to avoid anchoring on or near rocky features

would have minimized these impacts (MEC, 1995).

Overall impact to the resource from previous oil and

gas exploration is low.

In a cumulative sense, soft and hard substrate

habitat has also been physically impacted by previous

oil and gas activities on other leased areas within Central and Southern California. Drilling of exploratory

and development wells, placing platforms and constructing pipelines, discharging muds and cuttings are

all activities which impacted seafloor resources (refer

to section 4.6.2—Impacts from Previous Oil and Gas

Activities). Indeed, it is in large part because of the

potential cumulative impact on regionally important

hard substrate resources that extensive mitigation has

been required by MMS to protect even small areas of

hard substrate habitat. However, it has been shown

in detailed field studies of exploratory oil and gas drilling activities (MEC, 1995) and platform and pipeline

construction activities (Dunaway and Schroeder, 1989;

Hardin et al., 1993) that these mitigation measures

have been effective in mitigating impacts to hard bottom habitat. Therefore, cumulative residual impacts

to these habitats and resources from previous oil and

gas activities are low.

Fiber Optic Cable Installations. In the past few

years, a number of companies have applied for permits to install fiber optic cables for commercial communication purposes. The Global West Fiber Optic

Cable which traverses the California coastline from

Bodega Bay to Point Loma (San Diego) is proposed to

be laid offshore just outside existing OCS leases in the

Santa Maria Basin and south of the Santa Ynez Unit

in the Santa Barbara Channel. It comes to port at

Santa Barbara and Morro Bay. The cable is proposed

to be buried in the area just south of Gato Canyon

along the 220 fathom line (just outside the proposed

anchor radius for P 0460 #3). It also goes through

the Bonito Unit crossing four canyons. Global West

is using a cable that conforms to the contours of the

seafloor so that it can go into the canyons. They have

made an effort to avoid laying cable over rocky habitat and in areas of existing oil and gas pipelines. The

EIR projects that 70-km of cable (7% of the total mileage) will not be buried because it is laid in areas of

hard bottom. Of that distance, 9 km of the cable that

is laid on hard bottom occurs in the area from Estero

Bay to Santa Barbara, with most of the hard bottom

habitat identified near San Luis Obispo (Estero Bay).

Short segments crossing the canyons in the Bonito

Unit are identified as being laid over hard substrate

(Global West, 1999). Impacts to benthic resources in

general are low due to the small size of the fiber optic

cable and the lack of anchoring or other physical disturbances required to lay the cable.

Incremental Impacts from the Proposed

Action (2002-2006): Physical impacts to hard bottom seafloor resources are moderate for all wells except the Gato Canyon Unit, due to the potential to

impact stable hard bottom communities with anchors

and chains. Individual wells with multiple anchoring

events, and drilling of several wells with multiple anchoring events near sensitive hard substrate habitat

is likely to result in long-term impacts to plants and

animals, and alter habitat in several localized areas, a

moderate impact. If the only well approved was from

Gato Canyon, impacts to the resources would be low.
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Delineation Drilling Activities Offshore Santa Barbara County

If any of the other wellsites proposed in the other units

that are located proximal to hard bottom substrate

were approved, impacts could be moderate.

Due to the comparatively low volume of mud discharged during the drilling of delineation wells, the

water depth of proposed wellsites, and proximity of

wellsites to identified hard substrate, impacts on seafloor resources from drilling discharges are expected

to be low to moderate. Wellsites located a distance of

1,000 m from identified hard bottom substrate would

introduce low impacts to seafloor resources. Discharges from wellsites located within 1,000 m could

produce moderate impacts to hard bottom habitat due

to smothering, depending on the actual distance from

the feature, predominate currents and quality of the

habitat on the feature. Impacts on seafloor resources

from the proposed delineation wells are moderate, due

to the potential to impact hard bottom communities.

Physical impacts to hard bottom seafloor resources

are moderate for all wells except the Gato Canyon Unit,

due to the potential to impact stable hard bottom communities with anchors and chains. Individual wells

with multiple anchoring events, and drilling of several wells with multiple anchoring events near sensitive hard substrate habitat is likely to result in longterm impacts to plants and animals, and alter habitat

in several localized areas, a moderate impact.

Individual Projects. If wells for Point Sal only,

or Purisima Point only or Bonito Unit only is approved and the wellsite location chosen for the delineation well or wells in the unit is at a location which

impacts hard bottom resources, incremental impacts

of any one of these projects could be moderate. Contribution from any specific project, however, is small

in scope when compared to the impact from bottom

trawling activities.

If Gato Canyon only is approved, contribution

from the delineation well to the overall cumulative

impact is negligible, particularly when considering that

the habitat being avoided by oil and gas activities is

being regularly trawled by commercial fisherman.

All Projects combined. The drilling of five delineation wells as proposed from the identified possible

locations would cause moderate impacts if the locations drilled border hard bottom inhabited with stable,

diverse hard bottom communities and mitigation to

avoid them is not adopted. The impact is moderate

because the drilling activities have the potential to

impact several hard substrate areas, and in the absence of field data confirming the presence of sensitive

habitat, the assumption is that sensitive habitat could

be adversely impacted. In particular, moderate impacts would result due to the irreversible alteration of

locally significant habitat by anchors and anchor

chains. If the identified mitigation is adopted to avoid

impacting these areas or if the field surveys determine

these sensitive communities are not present on the

identified hard substrate features, moderate impacts

would be reduced to low impacts for the projects.

Summary and Conclusion (2002-2006): Soft

and hard bottom seafloor resources have and continue

to be impacted physically by commercial fishing activities. Impacts to hard bottom resources are significant due to alteration of the habitat, and the effect

reducing the complexity of the habitat has on the ecosystem. In particular, alteration of hard bottom habitat by rockfish bottom trawling activities is high. Past

oil and gas activities in the area, while having the

potential to impact hard bottom areas, have contributed little to the overall cumulative impact due to effective mitigation, demonstrated in field studies. Other

activities such as fiber cable projects, while affecting

resources adjacent to the proposed projects including

some hard bottom resources, contribute little to the

cumulative impacts due to the small area physically

affected.

Natural sediment turbidity flows contribute large

volumes of sediment on the ocean floor especially during large flooding years that overwhelm potential cumulative contributions by drilling muds in volume and

areal extent. Drilling muds and cuttings, even from

multiple development operations, have been found to

not contribute large scale impacts on the seafloor biota

(Hyland et al, 1990).

All of the proposed delineation projects contain

wellsite locations which could impact hard bottom resources, and if left unmitigated, and these wellsites

are chosen and sensitive hard bottom communities are

found to inhabit nearby features, irreversible habitat

alterations could occur from anchoring activities in

multiple locations.

Overall impacts to the relatively rare high relief

hard bottom habitat are high from several cumulative

sources. Every effort should be made to continue to

mitigate potential impacts to this resource. Overall

impacts to soft bottom resources is low, largely due to

the high variability of the resource and the biota’s

tolerance to change and ability to recolonize.

Potential Mitigation Measures for Cumulative Impacts: The primary mitigation for cumulative impacts is avoidance of hard bottom resources by

all activities. Any measure (avoidance, different gear

which does not rest on the bottom) which reduces the

physical impact bottom trawling fishing has on the

habitat and species found on the features, would measurably reduce impacts to this resource. All measures

which reduce physical impacts from oil and gas activities, such as avoidance of features with cuttings and

anchoring activities, also reduce overall cumulative

impacts to the resource. Based on studies of anchoring during development activities, properly mitigated

anchoring activity offshore during construction should

not produce significant impacts on the offshore biota
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Environmental Consequences, Cumulative Impacts (2002 - 2006), and Mitigation Measures

(Hardin et al., 1993). These impacts can be reduced if

platforms and pipelines avoid hard bottom and if anchoring activities during installation include vertical

handling procedures, anchor handling boats, shut down

plans during inclement weather, precautions against

dragging individual anchors and post-installation

monitoring.

5.2.5 IMPACTS ON KELP BEDS

This section discussed impacts from the proposed

project on kelp bed habitat. For a discussion of visiting or habiting fish, see the Fish Resources Section.

5.2.5.1 IMPACT OF THE PROPOSED ACTION

ON KELP BEDS

Criteria used to assess impacts to these resources

here and in chapter 6 are:

HIGH

Impacts that result in a measurable decline in a

population beyond that which can be explained by

normal variability, result in a measurable change regionally in species composition, ecological function or

community structure, or result in a measurable reduction in regionally important habitat are considered to be high impacts. These changes would be at

a level, areal extent, and duration that it would be

expected to place an individual species at risk, or alter the community structure or habitat on a regional

scale for many years. Irreversible alteration of regionally important habitat or reduction of protected

habitat would be considered high impacts.

MODERATE

Impacts that result in a measurable decline in

species composition, species abundance, ecological

function or community structure over several localized areas or result in alteration of locally important

habitat are considered moderate impacts. These

changes, while individually may persist for many years,

are localized and cannot be detected on a population

or regional level.

LOW

Impacts that result in a short-term change in

species abundance or composition, a temporary loss

in ecological function or community structure, a shortterm disturbance or temporary loss of access to locally important habitat are considered to be low impacts.

Impacts identified as high or moderate impacts

are considered to be significant. Impacts identified as

low impacts are considered insignificant.

5.2.5.1.1 IMPACTS COMMON TO ALL UNITS

There are no identified impacts to kelp beds from

the proposed delineation wells. Crew boats will adhere to approved vessel traffic corridors that purposely

avoid transit through kelp beds.

5.2.5.2 CUMULATIVE IMPACT ANALYSIS

FOR KELP BEDS

The cumulative impact analysis section considers cumulative impacts occurring between 2002-2006

which would occur with and without the proposed

projects. Another analysis of cumulative impacts can

be found in chapter 6.

5.2.5.2.1 CUMULATIVE IMPACTS (2002-2006)

Since there are no impacts from the Proposed

Action on this resource, no analysis of cumulative

impacts is appropriate here. However, impacts to this

resource could occur if development of the 36 undeveloped leases occurs. These impacts are discussed later

in the cumulative section for 2002-2030.
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5.2.6 IMPACTS ON FISH RESOURCES

Impact Level Definitions. The impact level analysis for fish resources in this document adopts the following impact level criteria:

HIGH

• A measurable change beyond normal variability in species composition, ecological function,

or community structure over several local areas or a large regional area for a period of 5

yrs or longer; or

• A measurable reduction in regionally important habitat for more than 5 yrs, or adverse

modifications of 10 percent or more of the habitat used by a given population lasting longer

than 5 yrs.

MODERATE

• A measurable change in species composition

or abundance beyond that of normal variability within several localized areas for a period

of 1 to 5 yrs;

• A measurable change in ecological function or

community structure within several localized

areas for less than 5 yrs; or

• A reduction in or disturbance to locally important habitat for more than 5 yrs.

LOW

• A short-term (less than 1 yr) change in species

composition or abundance;

• A temporary loss in ecological function or community structure; or

• A short-term disturbance or loss of access to

locally important habitat.

For the purposes of this document, high and

moderate level impacts are significant, while low level

impacts are considered insignificant.

5.2.6.1 IMPACTS OF THE PROPOSED

ACTION ON FISH RESOURCES

IMPACTS COMMON TO ALL UNITS:

Under section 305 (b) (2) of the Magnuson Fishery Conservation and Management Act (16 U.S.C. 1801

et seq) as amended by the Sustainable Fisheries Act

on October 11, 1996, Federal agencies are required to

consult with the Secretary of Commerce on any actions that may adversely affect Essential Fish Habitat. The Department of Commerce published an interim final rule (50 CFR Part 600) in the Federal Register (December 19, 1997, Volume 62, Number 244)

which detailed the procedures under which Federal

agencies would fulfill their consultation requirements.

As set forth in the regulations, EFH Assessments must

include: 1) a description of the Proposed Action; 2) an

analysis of the effects, including cumulative effects, of

the action on EFH, the managed species, and associated species by life history stage; 3) the Federal

agency=s views regarding the effects of the action on

EFH; and 4) proposed mitigation if applicable. Section 600.920 (h) describes the abbreviated consultation process MMS would like to follow for the proposed project. The purpose of the abbreviated consultation process is to address specific Federal actions

that may adversely affect EFH, but do not have the

potential to cause substantial adverse impacts.

The primary impact-producing activities associated with the proposed project are delineation drilling

operations and related activities, which will be common to all units. The impacting agents will include

drilling discharges, anchoring of the MODU, and explosive abandonment of the exploratory wells, if this

option is used. The following sections describe the

sources and types of these potential impacts.

Drilling Discharges. The drilling muds and cuttings of OCS oil and gas facilities could potentially

affect fish species through direct toxicity through exposure in the water or ingestion of prey that have

bioaccumulated toxins from the discharges, or through

damage to essential fish habitat. The EPA biological

assessment for the proposed reissuance of its General

NPDES permit for offshore OCS facilities in southern

California waters concludes that direct toxicity to

listed fish species, or their food base, should be minimal (SAIC, 2000a, b). All such discharges are required

to meet NPDES water quality criteria, which were established to protect biological resources outside the

100 m mixing zone. Significant impacts from OCS

discharges generally have not been associated with

fish. In fact, Love (1999) suggests that offshore platforms may provide nursery grounds for some species

of rockfish. And a successful mariculture operation

has been selling mussels collected from OCS platform

legs to local restaurants for over a decade. The mussels have consistently passed all FDA criteria for marketing shellfish. Impacts from drilling mud discharges

from five delineation wells are expected to be low.

Cuttings are generally not highly toxic, but depending on the subsurface formations being penetrated, they may contain toxic metals, naturally occurring radioactive elements, or petroleum. Cuttings
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Environmental Consequences, Cumulative Impacts (2002 - 2006), and Mitigation Measures

generally do not disperse far from the discharge point.

Impacts from drilling cuttings discharges from the five

exploration wells range from low to moderate, depending on the location of the wellsites in relation to high

relief habitat, and mitigation applied. Several of the

potential wellsite locations are proposed near potential hard substrate habitat. If biological surveys of

canyons and potential outcrop features identify important high relief habitat within 1000 feet of the

wellsite, discharges of cuttings from delineation wells

may result in moderate impacts to hard substrate (section 5.6.3).

Direct smothering and turbidity can adversely

affect filter-feeding organisms such as the sponges, cup

corals, and anemones found on naturally-occurring

hard bottom reefs. Because habitat supporting these

animals occurs within the immediate vicinity of the

Point Arguello platforms and pipelines, intensive monitoring was conducted during drilling activities at the

three Point Arguello platforms from 1986 to 1995.

Conclusions from Phase II and III that pertain to hard

substrate habitats are as follows:

1) Four of 22 taxa displayed significant time/dose

interactions representing possible negative responses to the drilling mud discharges in specific habitat. These taxa were: sabellids in deep

low-relief habitat, Caryophyllia sp(p) in deep

low relief and deep high-relief habitat, galatheid

crabs in deep low-relief habitat, and

Halocynthis hilgendorfi igborja in deep lowrelief habitat. Combined trends for the various taxa were not statistically significant.

 2) It was concluded that any biological effects

due to the drilling muds were related to physical effects of the increased particle loading, not

chemical toxicities.

3) Adverse biological effects on the benthos from

this study, as in other documented studies, were

limited to within 1 km of the discharge source.

Currently there are eight generic water-based

muds which have been approved for use by EPA. Discharge of oil-based drilling fluids into marine waters

is not authorized by EPA. The major toxic constituents of drilling muds are trace metals including arsenic, cadmium, chromium, lead, mercury, and zinc.

The toxicity of water-based drilling mud to juvenile

lobster and flounder was investigated by Neff et al.

(1989). They found that both species accumulated small

amounts of barium but no detectable chromium during 99 days of exposure to sandy sediment heavily contaminated with the settleable fraction of a used waterbased lignosulfonate drilling mud. There was some

physiological and biochemical evidence of stress in both

species, but growth was not significantly affected. The

authors concluded that, for the species and life stages

tested, there is little evidence for toxicity of waterbased drilling mud.

“Produced water” is the water present in the

source petroleum. No produced water is expected to

be discharged from any of the proposed drilling/well

testing activities.

Under section 402 of the Clean Water Act, the

Environmental Protection Agency (EPA) is authorized

to issue National Pollutant Discharge Elimination

System (NPDES) permits to regulate the discharges

of pollutants to waters of the U.S., the territorial sea,

contiguous zone, and ocean. EPA prepared an EFH

assessment for the reissuance of a General NPDES

permit for offshore oil and gas facilities in southern

California (SAIC, 2000c). The general conclusions of

the EFH assessment were that the continued discharge

from the 22 platforms offshore California will not adversely affect EFH outside the mixing zones described

as a 100 m radius from the discharge point. Within

the 100 m radius mixing zone, produced water discharges may have localized effects on water quality

and resident marine organisms, including EFH and

fish (SAIC, 2000c).

Given the short-term nature and limited scope

of the proposed drilling and testing program, low impacts to marine fish resources and EFH are expected

from drilling discharges.

Anchoring activities. A total of eight anchors

will be set and raised for each well site. The anchors

will impact the sea floor and raise clouds of sediment

a few meters into the water column. The silty sediments will likely settle to background within 500 m ,

and will not rise vertically within the water column

in such a fashion to affect background sediment levels

(normally 1-5 mg/l) over a large area (SAIC, 1986;

1995).

Section 5.6.3, Sea Floor Resources, concludes

that physical impacts to seafloor resources from anchoring operations are moderate, due to the potential

to impact high relief hard bottom communities. The

impacts would result in a long term impact in a locally important habitat or over a very localized area.

High impacts are not expected even if hard bottom is

contacted since the level of activity, five delineation

wells with 40 anchoring events, is unlikely to cause

sufficient disturbance to be felt at a population or regional level. If mitigations SF1 and SF2, identified in

section 5.6.3, are adopted, the impacts to fish resources

and EFH would be low, or insignificant.

Well Abandonment. Once the drilling and testing have been completed, each of the delineation wells

will be permanently plugged and abandoned (section

5.0). Part of the removal process involves cutting the

well casing string approximately 5m (15ft) below the

sea floor. The well casing may be cut mechanically, or

with explosives. In the latter case, shaped charges
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Delineation Drilling Activities Offshore Santa Barbara County

are lowered inside the casing and detonated. Commonly, such charges weigh in the range of 16-20 kg

(35-45 lbs) (Howorth et al., 1996; Howorth 1997).

Based on a 10 percent kill probability and using

a 56 lb charge, the following can be expected (Goertner

1981):

1) In water depths of 500 ft, 1-oz fish near the

surface can be killed out to a horizontal range

of about 700 ft. The only other fish which are

vulnerable to injury are those near the bottom

within a radius of 30-40 ft from the charge.

2) For severence explosions in water depth of 1000

ft, no significant kills of fish will occur.

If explosives are used in the well abandonment

process, the charge (16-20 kg) would be detonated in

the well casing 5 m below the seafloor. This positioning of the charge would dampen the explosion and restrict the shock and acoustic effects. Thus, the 10

percent kill zone described by Goertner would likely

shrink.

The use of explosives for well abandonment on

the Pacific OCS would require the implementation of

a wildlife mitigation plan designed to minimize impacts

to marine life (Howorth 1997). Typically, such a plan

has included the use of shipboard observers who would

be charged with collecting injured or dead fish after

the detonation. The detonation could also be postponed if the diver setting the charge reports an appreciable number of fish over the wellhead.

The latest wellhead removal on the Pacific OCS

using exposives, occurred in 1997 on Lease 0215, offshore Ventura. The diver placing the charge reported

about 20 juvenile rockfish over the wellhead before

detonation. After the detonation, 17 rockfish and 6

surfperch were collected by observers. In addition, 18

California barracuda were recovered (Howorth 1997).

The barracuda, an epipelagic fish, probably happened

to be swimming over the detonation site just as the

charge went off. A similar incident involving barracuda occurred on one occasion during the 4H platform removal project (Howorth 1996).

A small number of fish would be expected to be

lost after the explosive removal of a wellhead. However, given the short duration of the project, few fish

would be expected to be attracted to the wellhead and

a low mortality is expected. Overall, impacts from

this source are expected to be low. Low effects to fish

resources and EFH are expected.

5.2.6.1.1 SUMMARY AND CONCLUSION

Overall, activities associated with the proposed

delineation activities are expected to cause low impacts

to fish resources and EFH in the project area. No

impacts are expected from accidents or upsets.

5.2.6.1.2 MITIGATION MEASURES FOR

IMPACTS FROM THE PROPOSED

ACTION

The primary mitigation requirements include

avoidance of hard bottom substrate to the maximum

extent feasible. Section 5.6.3 Sea Floor Resources describes several measures to avoid potential impacts to

hard bottom substrate and related communities.

Mitigation FR1 (Explosive subsea removal).

Avoiding impacts to marine fish resources from the

use of explosives for well abandonment on the Pacific

OCS would require implementation of a wildlife mitigation plan similar to those employed for platform removal in California State waters (Howorth, 1997) and

in the MMS Gulf of Mexico OCS Region (NTL 99-G21).

Typically, such a plan has included the use of shipboard observers or divers (possibly supplemented by

aerial surveys), the establishment of a safety zone

around the detonation site for marine mammals and

birds, and monitoring of the zone to ensure that no

large numbers of fish are present when the charge is

detonated.

Implementation of this mitigation would make

it unlikely that any large fish mortality would occur

as a result of well abandonment operations associated

with the proposed delineation activities. Impacts to

marine fish resources would be low.

5.2.6.2 CUMULATIVE IMPACT ANALYSIS

FOR FISH RESOURCES (2002-2006)

CUMULATIVE IMPACTS WITHOUT THE

PROPOSED ACTION (2002-2006):

Section 5.0 describes the projects considered in

the cumulative analysis for the proposed delineation

activities. Possible sources of cumulative impacts in

the project area include on-going and proposed oil and

gas activities in Federal and State waters, Alaskan

and foreign-import tankering, and military operations.

Dredging and discharge of dredged material, aquaculture, coastal development, agriculture runoff, and commercial fishing are additional sources of potential cumulative impacts.

The projects discussed in this section include

past, present, and foreseeable actions that may produce impacts during 2002-2006, the expected duration

of the proposed exploration activities. Potential cumulative impacts are discussed below.

Offshore Oil and Gas Activities. There currently

are 23 offshore platforms in the Pacific OCS Region.

Of these, 4 are in the Santa Maria Basin, 15 are in the

Santa Barbara Channel, and 4 are in the San Pedro

Bay. Within the next 5 yrs, two new Federal projects

are likely to occur from existing OCS facilities, and 1
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Environmental Consequences, Cumulative Impacts (2002 - 2006), and Mitigation Measures

new State project is likely to occur from existing OCS

facilities. Section 5.0 describes the routine offshore

oil and gas activities that may result in impacts to

fish resources. These include geophysical surveys,

construction, drilling and production activities with

associated support activities, and the abandonment,

or decommissioning, of wells and offshore facilities.

As discussed in section 5.2.6.1, the major impact

agents expected from these proposed activities are noise

and disturbance, damage to hard-bottom habitat, and

drilling discharges. The potential use of explosives in

the abandonment of wells and offshore platforms also

raises the possibility of lethal impacts to fish resources.

Oil spills are the primary source of accidental impacts

to fish resources from offshore oil and gas activities

and tankering.

Geophysical surveys. Several studies have examined the effects of seismic energy on various life

stages of fish (e.g., Dalen and Knutsen, 1986; Falk

and Lawrence, 1973; Greene, 1985; Holliday, et al.,

1987; Kostyuchenko, 1973; Pearson, et al., 1987;

Turnpenny and Nedwell, 1994). The studies indicate

that direct damage to adult fishes is mainly to the

swimbladder and at fairly close ranges to the air gun.

The lethal range for coregonid fishes does not extend

beyond 19 ft (Falk and Lawrence, 1973). Damage to

anchovies does not extend past 3 ft (Holliday et al.,

1987). The risk of mortality to juvenile or adult fish

would therefore be limited to the occasional fish that

was close to the airgun array when shooting began;

other fish would move beyond the potentially lethal

range (Turnpenny and Nedwell, 1994).

Direct effects on fish eggs and larvae appear to

be minimal. Holliday et al. (1987) reported that northern anchovy eggs and 15-22-day-old larvae were not

significantly affected by sound pressures 3-4 times the

level expected from a seismic airgun array passing directly over a specimen at 10 ft. However, 2-day-old

and 4-day-old yolk-sac larvae suffered subtle, but statistically significant reductions in survival and growth

rates when exposed to the same pressure levels. Since

no physical damage was detected in the yolk-sac larvae, it was postulated that the observed survival and

growth rate reductions were due to interference with

the change in feeding behavior from yolk nutrition to

active plankton-feeding. Pearson et al. (1988) exposed

Dungeness crab zoeae to one discharge from a 7-airgun

array and found no significant difference in survival

or behavioral response compared to controls. In general, the acoustic pulse from airguns has relatively

little effect on marine invertebrates, presumably due

to their lack of a swim bladder.

Airgun energy appears to have behavioral effects

on fish. Generally, pelagic schooling fishes seem to

swim away and leave the area, while demersal fishes

appear to respond by flattening to the bottom. Pearson

et al. (1987) exposed several species of rockfish to

acoustic energy in a controlled test. Three behavior

patterns were noted: (1) the school dove to the bottom

and remained motionless; (2) the school dove to

midwater and swam rapidly in changing directions;

and (3) the school broke into smaller schools and fled

in different directions. These patterns were not always maintained throughout the exposure, indicating

that fish may habituate to the sound. The fish returned to their pre-exposure behavioral patterns within

minutes after the end of the sound presentations eliciting responses. Rockfish aggregations, as measured

by fathometer, showed no significant areal difference

between control and seismic sound emission trials,

although a decrease in aggregation height was detected

(Pearson et al., 1987). Perhaps more importantly, this

study showed a decrease in CPUE (catch per unit effort) of 52.4 percent during airgun exposure. However, the study did not conclude how long this decrease

in CPUE would be expected to last or over how great

a distance this reduction might occur. Studies by

Engas et al. (1993) and Lokkeborg and Soldal (1993)

reported that cod and haddock show significant catch

reductions over areas of several kilometers and periods of at least 5 days.

Any impacts to fish resources caused seismic

surveys are expected to be negligible. Any direct mortality to adults, eggs, and larvae would only occur very

close to the airgun arrays—within 5-20 ft of the source.

Some short-term behavioral changes might occur, but

would not cause a significant impact to the fish resources of the survey area. Pelagic fishes, such as

anchovies, mackerel, sharks, and barracuda, would

swim away from or would avoid the area during the

survey. Demersal fishes, such as rockfishes, flatfishes,

and ling cod would either flatten to the bottom or leave

the area during the survey. These behavioral changes

would be short-term and the fishes would return to

the area once the survey was completed.

Since 1963, more than 400 geological and geophysical surveys, including both 2-D and 3-D seismic

surveys, have been conducted in the Santa Barbara

Channel and Santa Maria Basin (table 4.0.1-6), and

many others have occurred in state waters. Most of

these surveys occurred during the 1970’s and 1980’s;

the most recent seismic survey offshore southern California was the Exxon 3-D seismic survey conducted in

the western Santa Barbara Channel in 1995 (MMS,

1995). Additional 3-D seismic surveys may occur during the next few years. However, no Pacific OCS operators have approached MMS with proposals to conduct such surveys to date. Significant cumulative impacts to fish resources from high-energy seismic survey activities have not been documented; evidence to

date indicates that cumulative impacts on the marine

environment are insignificant.

Construction and Drilling Activities. As of April

2000, more than 1,200 wells had been drilled in the
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Delineation Drilling Activities Offshore Santa Barbara County

Pacific OCS Region. This number includes 881 oil and

gas development wells drilled from platforms and 326

exploratory wells drilled from a variety of rigs, including mobile offshore drilling units (MODU’s), jack-ups,

barges, and drill ships. Currently, based on data from

1996 through 1999, slightly less than 2 development

wells per month are begun from Region platforms. No

exploratory wells have been drilled in the Pacific Region since 1989.

Adjacent hard-bottom habitats can be severely

impacted by construction activities including anchoring, placing platforms, and laying pipelines. The impacts can result in the crushing, and removal or burial

of substrate used for feeding or shelter purposes by

fish species. Disturbances to the associated epifaunal

communities may also result.

The discharge of drilling muds and cuttings can

result in varying degrees of change on the sea floor

and affect the feeding, nursery and shelter habitat for

various life stages of groundfish and shellfish species.

Exploratory activities may also result in increased

turbidity, which reduces sunlight available for photosynthesis in plankton and decreases primary productivity in the area.

Fish resources have likely experienced sublethal

and lethal impacts from past and present OCS oil and

gas construction and drilling activities. However, it

is unlikely that these impacts have amounted to more

than low impacts at a regional or even local (within 2

km of a construction or drilling activity) area. The

stipulations and conditions placed on OCS oil and gas

activities have helped to mitigate impacts to hard bottom areas and spawning or nursery habitats for fish

resources.

Offshore Facility Decommissioning. Section

5.2.6.1 discusses the process of exploratory well abandonment and the associated potential impacts to marine fish resources. Section 5.0 describes the processes

involved in decommissioning offshore facilities. For

purposes of analysis, it is assumed that decommissioning would encompass the complete removal of a platform and associated pipelines, with none of the leg

structure left in place to form an artificial reef. To

date, only one OCS facility in the Pacific Region has

been decommissioned—the Offshore Storage and Treatment (OS&T) vessel that formerly served the Santa

Ynez Unit platforms in the Santa Barbara Channel.

In addition, six offshore platforms in State waters in

the Channel have been removed—two in 1988 and four

in 1996 (table 4.0.1-6).

The Select Scientific Advisory Committee on Decommissioning explored possible marine ecological

implications related to the decommissioning of

California’s 27 offshore oil and gas production platforms. Biotic surveys of California platforms indicate

that many different species of fish and invertebrates

can be found on the current platform structures.

However, there is not any sound scientific evidence to

support the idea that platforms enhance or reduce regional stocks of marine fish species. The primary reason for this conclusion is that the 27 platforms represent a tiny fraction of the available hard substrate in

the SCB, suggesting that for the majority of species

any regional impacts from decommissioning are likely

to be small and possibly not even detectable empirically. However, because species differ greatly in life

history, population dynamics, and geographic distribution, it is possible that platforms could have a more

substantial effect on some key species. These species

of special concern could include several rockfish species whose low abundance has triggered severe restrictions on harvest and stock rebuilding plans. Bocaccio, for example, is estimated to have declined to about

1 percent of virgin biomass. Love et al. (2000) reported that Platform Gail had a density of adult bocaccio an order of magnitude greater than the average

density found on 61 natural reefs in appropriate depths.

In the short term there could be several local

impacts of removing platforms from the ocean. For

example, explosives could result in fish mortality on

or near the platform. Organisms on adjacent or

nearby natural hard substrate could be damaged by

anchors, or anchor scars could alter substrate and

impact its value as habitat for benthic species. When

the platform is removed from the ocean all the sessile

organisms on it will die, and the mobile species (fish

and invertebrates) would survive only if they could

successfully relocate to suitable habitat elsewhere. On

a long-term local basis, anchor scars and damage to

the bottom could persist, thus altering the habitat

quality for species associated with hard bottom substrate. A set of species associated with soft bottom

would likely develop in the area previously occupied

by the platform.

Mussel mounds located beneath the platform

would also be impacted. With no supply of shells, organic material, settled larvae and young stages arriving from the top layers of the water column, the biomass and species composition of the community associated with the mussel mounds would be impacted. If

the mussel mounds are removed, further impacts could

occur. If explosives are used, many organisms in the

vicinity could die. Removal would also result in loss

of the habitat. Sessile organisms would die and mobile ones would only survive if they could find suitable natural habitat nearby. To the degree that chemicals or other anthropogenic materials have become entrained in the mussel mound, these might be released

during the process of removal and might potentially

affect biota locally.

The current state of knowledge seems to indicate that complete removal of California platforms will

have low regional effects on fish stocks. Pipelines will

be abandoned in place, and are not expected to add to

the cumulative effects on fish resources of the SCB.
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Environmental Consequences, Cumulative Impacts (2002 - 2006), and Mitigation Measures

No offshore decommissioning activities are expected to occur in either Federal or State waters during the 2002-2006 duration of the proposed delineation activities.

Oil Spills. No oil spills are expected to result

from the proposed activities. As discussed in section

5.0, the cumulative oil spill risk for the project area

results from several sources: ongoing and projected

oil and gas production from existing OCS facilities in

the Santa Barbara Channel and Santa Maria Basin,

several proposed development projects on the Federal

OCS, ongoing production from one facility in State

waters in the Santa Barbara Channel, two reasonably

foreseeable oil and gas projects in State waters, and

the tankering of Alaskan and foreign-import oil

through area waters. Table 5.1-1 presents the estimated mean number of spills of various sizes and the

probability of their occurrence as a result of the described activities.

The most likely oil spill scenario for existing and

proposed offshore oil and gas activities is that one or

more oil spills in the 50-1,000-bbl range would occur

over the period 2002-2006, and that such a spill would

most likely be 200 bbl or less in volume. The probability that one or more spills of this size will occur

this period is 73.9 percent (table 5.1-1). The maximum reasonably foreseeable oil spill volume from future offshore oil and gas activities is 2,000 bbl, assumed for purposes of analysis to be a pipeline spill.

The probability of a spill of this size occurring during

the period 2002-2006 is 22.3 percent (table 5.1-1). Based

on data from tanker spills in U.S. waters, the mean

size for a tanker spill is assumed to be 22,800 bbl (with

a probability of occurrence of 38.8 percent for this

period; (table 5.1-1). The rationale for these estimated

spill sizes is presented in section 5.0. The potential

impacts to marine fish resources in the project area

from spills of each of these three sizes are discussed

below.

The level of impacts from such spills will depend

on many factors, including the type, rate, and volume

of oil spilled and the weather and oceanographic conditions at the time of the spill. These parameters would

determine the quantity of oil that is dispersed into the

water column; the degree of weathering, evaporation,

and dispersion of the oil before it contacts a shoreline;

the actual amount, concentration, and composition of

the oil at the time of shoreline or habitat contact; and

a measure of the toxicity of the oil.

Fate and Effects. When an oil spill occurs, many

factors determine whether that oil spill will cause

heavy, long lasting biological damage; comparatively

little damage or no damage; or some intermediate degree of damage. Among these factors are volume

spilled, geographic location, oceanographic and meteorological conditions, season, oil type, and oil spill

response and cleanup preparedness and method. Interpolating from the model of Ford (1985), a spill of

200 bbl could oil 1-19 km of coastline. The likely result would be patches of light to heavy tarring of the

intertidal zone along this 19 km stretch resulting in

localized changes to the community structure. The recovery time would depend on the environment. High

energy rocky coast will be mostly self-cleaned within

several months, while low energy lagoons and softsediment embayments can retain stranded oil residue

for several years. The same impacts would be expected

from a 2,000-bbl oil spill, and from a 23,000-bbl oil

spill, but over a larger area. It is estimated that a

2,000-bbl oil spill contact 3-53 km of coastline and a

23,000-bbl oil spill could contact 9-161 km of coastline.

Oil in the marine environment can, in sufficient

concentrations, cause adverse impacts to fish (NRC,

1985; GESAMP, 1993). The effects can range from

mortality to sublethal effects that inhibit growth, longevity, and reproduction. Benthic macrofaunal communities can be heavily impacted, as well as intertidal

communities that provide food and cover for fishes.

The field observations of an oil spill’s impacts

on the marine environment are taken mostly from very

large oil spills that have occurred throughout the world

over the past three decades. The Exxon Valdez spilled

about ~270,000 bbl of crude oil into Prince William

Sound and the Sea Empress released ~540,000 bbl of

crude oil off southwest Wales. The American Trader

spilled about ~10,000 bbl of crude oil offshore Huntington Beach, California. Due to pending litigation,

we are unable to provide a complete environmental

impact analysis of the September 1997 Platform Irene

oil pipeline spill of 163 bbl off the southcentral California coast.

Fishes. Fish can be affected directly by oil, either by ingestion of oil or oiled prey, through uptake

of dissolved petroleum compounds through the gills

and other body epithelia, through effects on fish eggs

and larval survival, or through changes in the ecosystem that supports fish. Although fish can accumulate

hydrocarbons from contaminated food, there is no evidence of food web magnification. Fish have the capability to metabolize hydrocarbons and can excrete both

metabolites and parent hydrocarbons from the gills

and the liver (NRC, 1985). Nevertheless, oil effects in

fish can occur in many ways: histological damage,

physiological and metabolic perturbations, and altered

reproductive potential (NRC, 1985). Many of these

sublethal effects are symptomatic of stress and may be

transient and only slightly debilitating. However, all

repair or recovery requires energy, and this may ultimately lead to increased vulnerability to disease or to

decreased growth and reproductive success.

The egg, early embryonic, and larval-to-juvenile

stages of fish seem to be the most sensitive to oil.

Damage may not be realized until the fish fails to
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Delineation Drilling Activities Offshore Santa Barbara County

hatch, dies upon hatching, or exhibits some abnormality as a larva, such as an inability to swim (Malins

and Hodgins, 1981). There are several reasons for

this vulnerability of early life stages. First, embryos

and larvae lack the organs found in adults that can

detoxify hydrocarbons. Second, most do not have sufficient mobility to avoid or escape spilled oil. Finally,

the egg and larval stages of many species are concentrated at the surface of the water, where they are more

likely to be exposed to the most toxic components of

an oil slick.

The Exxon Valdez oil spill (~270,000 bbl) provides several examples of how oil affects fish. For the

sensitive stages of fish (eggs, larvae, and juveniles)

the spill could not have occurred at a worse time. Pacific herring spawned along the shores of Prince William sound within weeks of the Exxon Valdez oil spill

in March 1989, resulting in increased egg mortality

and larval deformities. Also, fry from pink salmon

emerged from their gravel spawning redds and entered

the nearshore marine environment during the spill.

Site-specific occurrences of instantaneous mortality

suggest that a significant reduction in herring larval

production occurred because of the oil spill (Brown et

al.,1996). Brown et al. (1996) estimated that over 40

percent of the 1989 year-class was affected by Exxon

Valdez oil at toxic levels. The herring population in

Prince William Sound also suffered heavy losses in

1993 due to disease. However, it is not known what

role, if any, exposure to oil may have played in the

disease outbreak; natural variability and density-dependent effects could not be ruled out as the cause of

the small year-class and disease. Despite the reduction in larval production, reduced abundance in the

1989 year-class recruiting as 4-year old adults in 1993

could not be determined because natural processes affecting herring recruitment are poorly understood

(Brown et al., 1996).

Pink salmon, Dolly Varden, sockeye salmon, and

cutthroat trout exposed to oil from the Exxon Valdez

spill all showed reduced growth rates the season following the oil spill. Pink salmon also showed increased

egg mortality in oiled-versus-unoiled streams through

the 1993 season (Rice et al., 1996). Geiger et al. (1996)

estimated that 1.9 million adult pink salmon failed to

return to Prince William Sound in 1990, primarily

because of a lack of growth in the critical nearshore

life stage when they entered seawater in spring 1989

during the height of the spill. By 1991, 60,000 wild

adult pink salmon failed to return. In perspective, in

the years preceding the oil spill, returns of wild pink

salmon in Prince William Sound varied from a maximum of 23.5 million fish in 1984 to a minimum of 2.1

million in 1988. Since the spill, returns of wild pinks

have varied from a high of about 12.7 million fish in

1990 to a low of about 1.9 million in 1992. The decade

preceding the oil spill was a time of very high productivity for pink salmon in the sound, and, given the

tremendous natural variation in adult returns, it was

impossible to measure directly the extent to which

wild salmon returns since 1989 were influenced by the

oil spill. Based on intensive studies and mathematical

models following the oil spill, researchers determined

that wild adult pink salmon returns to the sound’s

Southwest District in 1991 and 1992 were most likely

reduced by a total of 11 percent (EVOSTC, 1999).

After the American Trader spilled ~10,000 bbl

of North Slope crude oil offshore Huntington Beach,

California, oil stranded along 22 km of coastline

(Gorbics et al., 2000). The natural resource trustees

(representatives from USFWS, CDFG, and NOAA)

determined that post larval juvenile white sea bass

were adversely impacted by the oil. Specifically, 10-

15mm juvenile fish were killed by oil when it mixed

with drift algae found near the surf line. The drift algae found in this area are the normal habitat for juvenile white sea bass and other croakers during and after the time of the spill (Gorbics et al., 2000).

Despite the fact that laboratory experiments and

field observations indicate that fish are susceptible to

adverse effects from hydrocarbons, with the exception

of the Exxon Valdez oil spill, no direct impacts on fishery stocks have been observed following catastrophic

spills. This is due in part to the complexities involved

with the natural process of recruitment, which produces tremendous natural variations in year-class

abundance that bear little relation to the size of the

parent stock. Thus, any impacts from catastrophic

oiling on fish stocks are probably masked by the natural variations in abundance. Also, massive fish kills

during oil spills have not occurred, or if they have it

is only in the egg and larval stages found in the surface waters. Adult fish have the ability to move away

from an impacted area. One of the worst spills in recent times, the tanker Sea Empress, released ~540,000

bbl of crude oil and ~4000 bbl of fuel oil into the sea

off Milford Haven waterway in southwest Wales on

February 15, 1996. Oil came ashore along 200 km of

coastline, much of it in a National Park and an area

of international scientific interest. The Sea Empress

Environmental Evaluation Committee, an independent

committee set up by the UK government, reported that

“Although tissue concentrations of oil components

increased temporarily in some fish species, most fish

were only affected to a small degree, if at all, and very

few died” (SEEEC 1998). The study found that about

40 percent of the oil evaporated soon after the spill

and around 52 percent dispersed into the water where

it was broken down by microorganisms. Surveys at

sea showed that the oil was not deposited in sediments

in significant quantities. Between 5 percent and 7 percent (~36,000 bbl) of the oil stranded on shore; however, one year after the spill less than 1 percent remained on the shore.
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Environmental Consequences, Cumulative Impacts (2002 - 2006), and Mitigation Measures

Although many factors contribute to the overall

impacts realized from an at-sea oil spill, fish are generally not adversely impacted at the population level.

Given the high energy and high productivity environment of the Point Arguello area, the common meteorological and oceanographic conditions, and the oil

spill preparedness and response capabilities in place,

direct measurable effects to any fish stock abundance

from a 200 to 23,000 bbl oil spill off the coast of Point

Arguello, California are unlikely.

Food Web and Habitat. Fish can also be affected

indirectly by oil through changes in the ecosystem that

supports fish. In simplistic terms, this ecosystem would

include all prey species and habitats the fish use during all life stages.

Perhaps the most important food on which all

fish rely during their larval and juvenile stage is plankton. In general, the studies to date indicate that zooplankton are more susceptible to effects from oil spills

than are phytoplankton. Even if a large number of

algal cells were affected during a spill, regeneration

time of the cells (9-12 hours), together with the rapid

replacement by cells from adjacent waters, probably

would obliterate any major impact on a pelagic phytoplankton community (NRC, 1985). After the Tsesis

spill in the Baltic Sea, there was a decrease in zooplankton in the vicinity of the wreck. The quantity of

phytoplankton increased briefly and it was concluded

that the change was due to a decrease in the amount

consumed by zooplankton. Similar results have been

obtained in long-term oiling experiments. Individual

organisms in oil spills have been affected in a number

of ways: direct mortality (fish eggs, copepods, mixed

plankton), external contamination by oil (chorion of

fish eggs, cuticles and feeding appendages of crustacea), tissue contamination by aromatic constituents,

abnormal development of fish embryos, and altered

metabolic rates (Longwell, 1977; Samain et al., 1980).

The effects appear to be short-lived and there are seldom prolonged changes in biomass or standing stocks

of zooplankters in open water near spills, due largely

to their wide distribution and rapid regeneration (Van

Horn et al., 1988). During the Exxon Valdez spill,

Celewycz and Wertheimer (1996) studied the impact of

the spill on zooplankton and epibenthic crustaceans,

potential prey species of pink salmon. They did not

detect any reduction in abundance of either zooplankton or epibenthic crustaceans between oiled and nonoiled locations in either 1989 or 1990.

Intertidal and subtidal macrophytes provide shelter and food for fish and for fish prey species at various life stages along the northern Santa Barbara

County coast. The habitats involved here include both

high energy rocky shorelines, sand and cobble beaches,

and the nearshore subtidal environment. Intertidally,

the red alga Endocladia muricata and the brown alga

Pelvetia spp. are species common to the area, as is

surf grass (Phyllospadix spp.). Giant kelp, Macrocystis

pyrifera is common to the nearshore subtidal area.

Intertidal macrophytes seem to be more vulnerable to

oiling than subtidal macrophytes. Losses of intertidal

algal cover have been described after several spills.

However, recovery appears to occur quite readily

(Topinka and Tucker, 1981), though imbalances in the

macrophyte community can persist for years. The proliferation of opportunistic intertidal algal species after a spill is invariably a direct result of the elimination, by the oil, of naturally occurring grazers—limpets and other intertidal herbivores (NRC, 1985). Little

evidence exists that kelp is harmed by oil (MMS, 1992).

An oil spill of 200 bbl would probably result in light to

heavy tarring of the intertidal zone if oceanographic

conditions carried the oil to shore. Impacts to intertidal macrophytes would be minimal and patchy over

an estimated 10 km or less of shoreline. Raimondi

(1998) reported that species abundance at two research

sites within the exposure zone of the 163 bbl Irene

pipeline spill showed no significant changes that could

be attributed to the oil spill. Barnacle abundance at

one site decreased in the Fall 1997 and Spring 1998

surveys, however no fresh tar or oil was observed at

the site. In Spring 1998 surveys, the same site also

showed decreases in mussels and surf grass cover, but

these impacts were attributed to the effects of strong

El Nino enhanced storms that ravaged the site in January and February of 1998. No measurable impacts

would be expected to subtidal macrophytes from a 200

bbl oil spill.

Fluctuations of benthic and intertidal invertebrate populations may affect the fishes that normally

feed on them. Considerable work has been done studying the effects of oil on macroinvertebrates. Most susceptible are those species inhabiting the intertidal zone,

especially those found in lagoons, embayments, estuaries, marshes, and tidal flats. This risk derives from

two factors: high oil concentrations and shallow depth

of the water column. Aside from the physiologically

toxic effect, intertidal organisms may be entrapped or

suffocated by oil. In fact, a major impact of the Sea

Empress spill was to the intertidal invertebrate community. Heavy limpet mortalities were recorded, and

periwinkles and topshells died, though in lesser numbers. Amphipod mortalities were extensive, although

substantial recolonization was evident at most sites

one year later (SEEEC, 1998). Gorbics et al. (2000)

reported that overall mortality of bean clams as a result of the American Trader spill (~10,000 bbl of crude

oil) in February 1990 was estimated to be 24 percent.

Sand crabs showed an increase in the body burden of

aliphatic hydrocarbons until June 1990. It can be assumed that the oil from the American Trader that

stranded along 22 km of coastline near Huntington

Beach resulted in a significant increase in the mortality of intertidal invertebrates (Gorbics et al., 2000).
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Delineation Drilling Activities Offshore Santa Barbara County

It can take several years for limpet and other

mollusc populations to recover completely at heavily

impacted sites. A 200- to 23,000-bbl oil spill in the

western Santa Barbara Channel that contacted shore

would likely result in mortality to various intertidal

macroinvertebrates, including barnacles, limpets,

mussels, starfish, anemones, and black abalone. Smothering would be the most common cause of mortality

and would be limited to direct contact with weathered

tar balls from the oil spill. After the 163 bbl Irene pipeline spill in September 1997, sand crabs within the

spill zone showed significant hydrocarbon contamination (J. Dugan, UCSB, pers. com.). Sand crabs are an

important component of the diet of several fishes.

Though fish can metabolize hydrocarbons they accumulate, this process requires energy and may lead to

an increased vulnerability to disease and decreased

growth or reproductive success. Since sand crabs were

contaminated after the oil spill, one can also assume

that other invertebrates such as myssids, amphipods,

and polychaetes were affected. In fact, one predatory

polychaete has not repopulated some areas of the spill

zone, though it can be found in areas outside the zone

(J. Dugan, UCSB, pers.com.).

Coastal and offshore waters and benthic subtidal

environments are important habitat for all fish species. The coastal and offshore waters are any areas

seaward of the low tide level and include bays, open

coastal waters, and the deep ocean. Oil spills in the

open ocean do not appear to have as severe an effect

on the biota as oil in coastal water or in the shore

zone (NRC, 1985). This may be due to the fact that

the shore zone and coastal waters are subject to serious effects from chronic pollution and an oil spill in

this area is impacting a stressed environment. Benthic

subtidal environments may be impacted when oil spilled

onto the surface of the water column is transferred to

bottom sediments through sorption on clay particles

and subsequent sinking, sinking of dead organisms,

uptake and packaging as fecal pellets by zooplankton,

or direct mixing to the bottom in shallow water. This

may impact fish both directly and indirectly. After the

Tsesis oil spill, herring reproduction was significantly

reduced in the spill area. Nellbring et al. (1980) reported that the reduced reproduction was due to a decrease in amphipod populations that graze on fungi

growing on the fish eggs, leaving the eggs susceptible

to fungal damage. Oiling of the sediments following

the Amoco Cadiz spill had deleterious effects on plaice

and sole, including reduced growth and increased incidence of fin and tail rot (Conan and Friha, 1981). In

fact, flatfish may be particularly susceptible, since they

spend a considerable amount of time lying on the bottom or even partially buried in the sediments.

An evaluation of the literature reveals that oil

spills can cause mortality and sublethal effects on fish

at all life stages, their prey, and their habitat. However, whether or not these impacts result in measurable adverse effects on EFH or fish resources is more

difficult to determine. In 1985, a National Research

Council committee found “no irrevocable damage to

marine resources on a broad oceanic scale” as a result

of oil pollution from either chronic, routine sources

or from occasional major spills. At the same time, however, it cautioned that further research is needed before an unequivocal assessment of the environmental

impact of oil pollution can be made, particularly as it

applies to specific locations and conditions.

Given the national oil spill data collected from

the Gulf of Mexico and Pacific Region OCS programs

over the last 30 years, MMS expects that such a spill

would probably be less than 200 bbl, and the maximum reasonably foreseeable is 2,100 bbl. Given the

location, normal meteorological and oceanographic

conditions, and oil spill response capabilities of the

area, low adverse effects are expected to EFH or fish

resources from an oil spill in this size range. Any direct mortalities to fish would probably occur only in

the egg and larval stages found in the surface waters

in the immediate vicinity of the spill. Depending on

the oceanographic conditions at the time of the spill,

some oiling of the intertidal zone along the south or

central California coast or the northern Channel Islands is expected. Under normal conditions for the

area, significant mixing and weathering of the oil

would evaporate much of the toxic light-end hydrocarbons into the atmosphere, disperse the oil into the

water column, and likely break the slick into smaller

patches. The weathered tar balls would likely cause

some mortality to intertidal macrophytes and invertebrates through smothering. Elevated hydrocarbon levels in nearshore invertebrates would be likely, leading

to increased stress and potential decreases in growth

and reproduction in fish feeding upon the invertebrates. These effects are expected to be short-term

under normal conditions; however, oil may become

sequestered in the sediments of low-energy embayments

and persist for several years.

Accidental oil spills present an ongoing source

of potential impacts to fish resources. The cumulative risk of oil spills arises from multiple sources, including offshore oil and gas activities in Federal and

State waters and both Alaskan and foreign-import

tankering. Tankering represents the greatest risk of

an oil spill in the SCB. This risk is tempered by recently implemented or proposed mitigation (such as

the rerouting of tankers farther offshore along the

central California coast) and, as discussed in section

5.0, by modern oil spill response capabilities. The mean

spill size derived from the U.S. Coast Guard database

for accidents in U.S. waters is 22,000 bbl. A spill this

size could contact up to 161 km of coastline. Fish

resources and EFH would likely experience low impacts from a spill this size. The water quality from the
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Environmental Consequences, Cumulative Impacts (2002 - 2006), and Mitigation Measures

Point Conception area north and offshore the Channel Islands remains good. This area is very productive

and is important habitat for many marine fish species. A large oil spill would impact the water quality

of this habitat. Although only minimal adverse impacts to fish populations and their prey species would

be likely from such an event, EFH in the Southern

California Bight is stressed due to overfishing, and

degraded water quality in estuaries south of Point

Conception. Degradation of the water quality north of

Point Conception due to an oil spill would cause further stress to EFH. The impacts to water quality from

an open ocean spill would be short-term and not expected to last more than several days.

The potential for an oil spill occurring from continued oil and gas activities at the existing platforms

on the Pacific OCS and State tidelands represents an

insignificant incremental increase to the overall cumulative oil spill risk for fish resources.

Other Activities. NMFS (1998a,b) has identified

several fishing and non-fishing activities that may

cause adverse impacts to Federally-managed fish species and Essential Fish Habitat (EFH) along the Pacific Coast. These include dredging and discharge of

dredged material, water intake structures, aquaculture, wastewater discharge, oil and hazardous waste

spills, coastal development, agricultural runoff, commercial marine resource harvesting, and commercial

fishing. Most of these activities occur throughout the

California, Oregon, and Washington coastal habitat

and all of these activities and impacting agents exist

in the southern and central California coastal zone.

As a result, marine water quality has been impacted

by municipal, industrial, and agricultural waste discharges and runoff in much of the Southern California Bight (MMS, 1992).

An estimated 1.34 billion gallons of treated municipal sewage per day are discharged into the waters

off southern California (SCCWRP, 1990). Despite current efforts to limit sewage discharge, pollution and

its effects on fish of the SCB will remain at its present

level over the next 25-40 years due to increasing coastal

population.

Fishing pressure exerted by the combined efforts

of commercial and marine recreational fishers is one

of the most important man-induced stresses on some

fish resources. Fishing pressures are expected to remain high in southern and central California as demand increases and fishing practices become more efficient. This will result in continuing short- and longterm declines in some fish stocks. Furthermore, NMFS

(1998) stated that fishing gear impacts the biological

seafloor resources by removing marine plants, corals

and sessile organisms, upending rocks, leveling rock

formations, and re-suspending sediments which irreversibly alters the marine habitat complexity. There

are few, if any, large virgin marine habitats off the

Pacific Coast. High relief rock piles that are not accessible to trawl gear are usually accessible to commercial longline and recreational hook-and line gear.

INCREMENTAL CUMULATIVE IMPACTS OF

THE PROPOSED ACTION (2002-2006):

As discussed in section 5.2.6.1, routine activities associated with the proposed delineation activities are expected to result in low impacts to marine

fish resources in the immediate area around the proposed well sites. No impacts are expected from accidents or upsets.

SUMMARY AND CONCLUSION (2002-2006):

 Several fish stocks in the SCB are depressed.

Unfortunately, it is difficult to apportion the reasons

for a fishery’s demise among overfishing, habitat degradation, pollution, and natural variability of the population. However, as fishery managers gather more

detailed knowledge about fish life histories, including

potential linkages between fish recruitment and longterm changes in ocean climate, they will be better able

to prevent the overexploitation and resulting population crashes of one fish species after another. Many

of these fish stocks have been monitored for less than

the span of one of their generations. It may take decades of monitoring to fully ascertain the long-term

feasibility of current fishery restrictions, proposed

marine protected areas, and other fishery management

options. The 1996 amendments to the MagnusenStevens Act addresses sustainable fisheries and sets

guidelines for protecting marine fish resources and

habitat from fishing related and non-fishing related

activities.

The proposed delineation project will add incrementally to the overall impacts on fish resources in

the Bight. The primary impacts would be to

hardbottom habitat in the immediate vicinity of the

well site and MODU anchoring system. No oil spills

are expected to result from the proposed delineation

activities. Due to the short duration of the proposed

projects, the distances between the projects, and the

mitigation measures placed on the projects, the environmental effects of the proposed project on the fish

resources and EFH of the SCB are expected to add a

negligible increment to the overall cumulative effects

on fish resources in the SCB.
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5.2.7 IMPACTS ON MARINE AND COASTAL

BIRDS

This section analyzes the impacts of the proposed

projects on marine and coastal birds. (Threatened and

endangered species are analyzed in section 5.2.9.) The

marine and coastal birds of the project area are described in section 4.6.5. Marine and coastal birds may

be vulnerable to several potentially adverse impacts

from operations associated with the proposed project.

Operations assumed to occur as a result of the proposed projects include: towing and anchoring the

MODU, support vessel traffic, helicopter flights, drilling, various discharges, barge transit and anchoring,

and well abandonment. These operations are described

in section 2. As stated in section 1.0, no oil spills are

expected to occur from the proposed drilling activities

that make up the proposed projects, and therefore, no

impacts to marine and coastal birds from oil spills are

expected.

In preparation for this analysis, the following

impact level definitions were developed:

HIGH

Impacts are expected to include direct mortality,

reduced survivorship, declines in reproductive success,

shifts in distribution, and possibly, changes in species

diversity. Mortality is expected to involve thousands

of birds, with many more experiencing sublethal effects. This would be expected to result in measurable

changes in distribution and abundance in the project

area. Effects are expected to continue for more than 2

years.

MODERATE

Impacts are expected to include direct mortality,

reduced survivorship, declines in reproductive success,

and shifts in distribution. Mortality is expected to

involve hundreds of birds from the project area, with

many more experiencing sublethal effects. This would

be expected to result in measurable changes in distribution and abundance in the project area. Effects are

expected to continue for 1-2 years.

LOW

Impacts result in biologically important (e.g., a

change in abundance, species diversity, reproductive

success, growth rates, and/or survival) change(s) in a

few local populations (e.g., a colony or beach), mainly

due to high levels of disturbance. In this analysis,

minor changes in behavior (e.g., a bird moving out of

the path of an approaching boat) are not considered

biologically important and are not indicative of an

impact. Mortality, if any, would be limited to the loss

of 10’s of birds, with many more experiencing sublethal effects. Effects are expected to continue for no

more than one year.

For the purposes of this document, high and

moderate impacts are considered to be significant,

while low impacts are insignificant.

5.2.7.1 IMPACTS OF THE PROPOSED

ACTION ON MARINE AND COASTAL

BIRDS

The following is a discussion of the impacts of

operations to marine and coastal birds that are common to all units; no impacts to marine and coastal

birds are unique to any one unit. Operations associated with the proposed projects described in section 2

that could have an effect on marine and coastal birds

are: towing the MODU, support vessel traffic, helicopter flights, barging, and well abandonment. Other

potential sources of disturbance, including the noise

and activity associated with drilling operations, are

not expected to have an effect. Platform discharges

are not expected to have an effect due to the high degree of dilution that would occur and the fact that

bioaccumulation of associated pollutants is not expected

(SAIC, 2000).

The seabirds that are probably most sensitive to

disturbance are those that are actively nesting. The

activities associated with moving and positioning the

MODU, support vessel traffic, and barging will be conducted either well away from any seabird colony or at

ports (e.g., Port Hueneme) where there are no seabird

colonies. These activities can also disturb birds at

sea, but these effects would be limited to the immediate vicinity of the disturbance and would be very short

in duration (e.g., a few minutes). Vessel traffic of various types is common throughout the project area, and

seabirds have most likely become habituated to this

activity. Seabirds are as likely to be attracted to these

activities as dispersed by them. Shorebirds and

marshbirds would not be affected by these activities

because these birds are restricted to the shoreline.

Helicopter flights can have a negative impact on

seabirds, although seabird reactions to helicopters and

other aircraft are complex, depending on the species

involved; colony size; previous exposure levels; and

the location, altitude, and number of flights (Hunt,

1985). Seabirds may also habituate to air traffic over

time (Hunt, 1985). Helicopter flights associated with

the proposed projects will originate from either the

Santa Maria or the Santa Barbara Airport (both of

which are in Santa Barbara County), depending on

the unit. The airports and the number of helicopter

flights planned for each unit is shown in table 4.0.1-7.

Low-flying aircraft, especially helicopters, can disturb

nesting birds, causing them to leave their nests unattended. Although the adult(s) may be absent from the
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nest for only a short period of time, eggs and nestlings may be lost either due to exposure or predators,

such as western gulls. Birds that nest on offshore

rocks and cliffs are especially vulnerable because they

may accidentally cause their eggs or young to fall from

cliff ledges when they take flight due to a low-flying

helicopter. Helicopters may also disturb roosting birds,

such as cormorants, gulls, and pelicans. Helicopter

flights may especially be a problem in undisturbed areas like the Pacific Northwest or Alaska. Studies in

the Bering Sea have demonstrated that repeated aircraft flights near colonies may have been a factor contributing to fewer nesting attempts and reduced reproductive success of nesting seabirds (Biderman and

Drury, 1978; Hunt et al., 1978). Due to the high background level of aircraft flight activity that occurs

throughout much of the project area, however, birds

may be habituated to this type of disturbance. Flights

at low altitudes could still be a problem for nesting

birds, however.

Within the project area, the vast majority of seabird colonies are located on the northern Channel Islands within the Channel Islands National Marine

Sanctuary and Channel Islands National Park. Helicopter flights from the proposed projects are not expected to cross these areas. However, a small number

of seabirds also nest along the mainland from Point

Conception, north. The pigeon guillemot is the most

abundant nesting seabird in this area (Carter et al.,

1992). Other species, including pelagic cormorant,

western gull, and rhinoceros auklet, occur in very

small numbers. Most nests in this area are located at

Point Sal and Point Arguello. Impacts to these species could occur if low altitude (less than 1,000 ft) flights

over their colonies take place during the breeding season. Although pigeon guillemots may be the most

abundant nesting seabird in this area, they may not

be as sensitive to helicopter flights as other species

because they nest in cracks and crevices and abandoned burrows. It should also be noted that only those

helicopter flights in table 4.0.1-7 that originate from

the Santa Maria Airport and service the Point Sal and

Purisima Point Units could potentially cross these

seabird nesting areas; based on the flight route for

the Santa Barbara Airport (T. Marr, Petroleum Helicopters, Inc., pers. comm.), flights from that airport

do not cross any seabird colonies. The flight path

across the shoreline for helicopters from Santa Maria

is well south of Point Sal and does not cross any seabird nesting areas (E. Rudolfs, Arctic Air, pers. comm.).

Also, Vandenberg AFB, where most of the seabird colonies that might be exposed are located, has a 1,000 ft

flight restriction over the major seabird colonies, which

further protects most of the seabirds in this area (N.

Read, VAFB, personal comm.). Based on the relatively

small number of flights from the Santa Maria Airport,

the fact that the normal flight path for helicopters does

not cross any seabird colonies, and the flight restrictions on Vandenberg AFB, no impacts to marine and

coastal birds from helicopters are expected.

Shorebirds and marshbirds could also be disturbed by low-flying helicopters, but the few species

that nest in the project area occur in very low numbers and are unlikely to be affected.

Another activity associated with the proposed

projects, well abandonment, could harm seabirds under certain circumstances. Each of the delineation

wells in these projects will be permanently plugged

and abandoned (section 2). As part of the abandonment process, the casings for these wells may be cut

either mechanically or with explosives. Use of explosives raises the possibility of impacts to seabirds. Although no injuries to seabirds from well abandonment

with explosives have been reported, brown pelicans,

cormorants, gulls, and phalaropes have been killed or

injured due to other sources of underwater explosions

(Fitch and Young, 1948). To be killed or injured during well abandonment with explosives, a bird would

have to be submerged at the exact moment of the explosion. Although safety information is not available

for birds, research on fish (Gertner, 1981) and marine

mammals (Young, 1991) indicates that, for the amount

of explosives used in well abandonment, a safe distance for these animals ranges from about 1,000-2,000

ft, depending on the species (for details, see 5.4.4.1 for

fish and 5.4.6.1 for marine mammals). Explosive

charges will be set off 5 m (15 ft) below the sea floor,

which would dampen the effect of the blast and reduce

the area in which birds could be killed or injured; therefore, a bird would probably have to be submerged directly under the MODU to be affected by well abandonment. The seabirds that might be injured are those

that forage underwater. These include grebes, loons,

shearwaters, scoters, and alcids. Many of these species remain relatively close to shore and would not be

affected. Gulls might be attracted to the area by the

dead fish that result from underwater explosions, but

gulls feed on the surface and would not be affected.

Based on the damping effect of the explosions being

below the sea floor and the very low probability that

seabirds would be both submerged at the exact moment of an explosion and in close enough proximity to

be killed or injured, no impacts to marine and coastal

birds from well abandonment are expected.

5.2.7.1.1 SUMMARY AND CONCLUSION

No impacts to marine and coastal birds are expected as a result of operations associated with the

proposed projects, including helicopter traffic and well

abandonment, either for all units combined or any

individual unit.
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5.2.7.2 CUMULATIVE IMPACT

ANALYSIS FOR MARINE AND

COASTAL BIRDS (2002-2006)

Since there are no impacts from the Proposed

Action on marine and coastal birds, no analysis of

cumulative impacts is appropriate here. However,

impacts to marine and coastal birds could occur if development of the 36 undeveloped leases occurs. These

impacts are discussed in section 6.2.7.

5.2.8 IMPACTS ON MARINE MAMMALS

The impact analysis for marine mammals in this

document adopts the following impact level criteria:

HIGH

Impacts result in the loss of hundreds of marine

mammals from the project area due to direct mortality, reduced survivorship, declines in reproduction,

and/or a shift in distribution. Effects are expected to

continue for 5 or more years.

MODERATE

Impacts result in the loss of tens of marine mammals from the project area due to direct mortality, reduced survivorship, declines in reproduction, and/or

a shift in distribution. Measurable, area-wide changes

in abundance are not expected unless the impacts are

confined to a limited area (e.g., San Miguel Island).

Effects are expected to continue for 1 to 5 years.

LOW

Impacts result mainly in local changes in behavior (e.g., disruption of foraging) and/or displacement

from rookery, haul-out, or foraging habitats due to

disturbance. Mortality, if any, would be limited to the

loss of a few individuals, although many more might

suffer from sublethal effects. Impacts are expected to

continue for no more than 1 year.

Impacts below these levels, involving no death

or life-threatening injury of any marine mammal, no

displacement from preferred habitat, and no more than

minor disruption of behavioral patterns, are defined

as negligible. For purposes of this document, high

and moderate impacts are considered to be significant;

low impacts are considered to be insignificant.

Marine Wildlife Contingency Plans. As part

of the Project Descriptions submitted to MMS, marine wildlife contingency plans (MWCP’s) have been

prepared for each of the units where delineation activities are proposed (Aera, 2000a,b; Nuevo, 2000;

Samedan, 2000). The MWCP’s outline procedures intended to minimize potential impacts to marine mammals from the proposed delineation drilling operations,

specifically those involving the use of marine vessels

and helicopters.

For marine vessels, the guidelines specify that:

• Support vessels will make every effort to maintain a distance of 1,000 ft (300 m) from sighted

whales.

• Support vessels will not cross directly in front

of migrating whales.

• When paralleling whales, support vessels will

not operate at a speed faster than the whales

and will maintain a constant speed.

• Female whales will not be separated from their

calves.

• Support vessels will not be used to herd or drive

whales.

• If a whale engages in evasive or defensive action, support vessels will drop back until the

animal calms or moves out of the area.

The MWCP’s also provide guidelines for immediate operator notification of the NMFS Stranding

Coordinator in Long Beach in the event of a support

vessel collision with a marine mammal.

Support helicopters are advised to maintain at

least a 1-mile (1.6-km) distance from observed wildlife

concentrations and known wildlife concentrations,

such as pinniped haul-out areas. The guidelines call

for support helicopters to maintain a minimum overflight altitude of 1,500 ft (460 m) when unexpectedly

encountering individuals or groups of whales at sea.

5.2.8.1 IMPACTS OF THE PROPOSED

ACTION ON MARINE MAMMALS

The primary impact-producing activities associated with the Proposed Action include delineation drilling operations with associated support activities and

are common to all the units. The major impact agents

expected from these proposed activities are noise and

disturbance and drilling discharges. The potential use

of explosives in the abandonment of the delineation

wells also raises the possibility of lethal impacts to

marine mammals. The following sections describe the

sources and types of these potential impacts.

Noise and Disturbance. The proposed activities

associated with the delineation projects, including drilling and transportation, are among the most common

sources of man-made, low frequency noise that could

affect marine mammals. The source level of a sound

produced by activities such as these is described as

the amount of radiated sound at a particular frequency
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and distance, usually 1 m from the source, and is commonly expressed in dB re 1 μPa. Much of the following discussion is derived from the detailed review of

the sounds produced by offshore activities in

Richardson et al. (1995).

Offshore Drilling. As described in section 2.2,

the semi-submersible drilling rig to be used for the

proposed delineation activities will probably be a

SEDCO 700-series rig, although the operators have

not yet chosen a specific drilling vessel. It is estimated that noise from drilling activities will last less

than 2 months at each well location (table 2.1.2-1).

The sound levels produced by drilling from conventional, semi-submersible drilling rigs are relatively low

(Gales, 1982; Richardson et al., 1995). Greene (1986)

estimated source levels of about 154 dB re 1 mPa in

the 10- to 500-Hz band for the SEDCO 708 in the

Bering Sea. Gales (1982) measured levels of 125 dB re

1 mPa at frequencies of 29-70 Hz at distances of 13-15

m from two diesel-powered semisubmersibles, with

somewhat lower infrasonic tones at 7-14 Hz. No source

levels were estimated.

The reactions of pinnipeds (seals and sea lions)

to offshore drilling noise have not been extensively

studied (Richardson et al., 1995). Observations of

ringed and bearded seals in Arctic waters indicate some

tolerance of drilling noise. Seals were observed to

approach and dive within 50 m of a sound projector

broadcasting steady low-frequency (less than 350 Hz)

drilling sound; received levels at this distance were

about 130 dB re 1 mPa (Richardson et al., 1990a, 1991,

1995).

Most studies of the reactions of odontocetes

(toothed whales) to offshore drilling noise have involved

belugas (Richardson et al., 1995). In one study, belugas exposed to playback sounds from the SEDCO 708

semi-submersible rig reacted in one test at a distance

of 300-500 m by increasing swimming rate and turning away from the projector. However, most of the

belugas passed close to the projector (Stewart et al.,

1983; Richardson et al., 1995). In general, odontocetes

appear to be fairly tolerant of drill rig noise

(Richardson et al., 1995).

For gray whales off the coast of central California, Malme et al. (1984) recorded a 50-percent response

threshold to playbacks of semi-submersible drilling

noise at a received level of 120 dB re 1 mPa. A similar

playback study with humpback whales (Malme et al.,

1985) demonstrated no clear avoidance responses at

received levels up to 116 dB re 1 mPa. These levels

would be reached well within 100 m of the drill rig in

both nearshore and shelf-break waters; therefore, the

predicted radius of response for grays, humpbacks, and

probably other baleen whales as well, would also be

less than 100 m. Richardson et al. (1995) also predicted similar radii of response for odontocetes and

pinnipeds.

As discussed in section 4.6.6.1, migrating gray

whales generally travel within 3 km (1.6 nm) of the

shoreline over most of the route, unless crossing

mouths of rivers and straits (Dohl et al., 1983; Braham,

1984a). South of Point Conception, the migration

pathway widens; gray whales often cross the Santa

Barbara Channel and travel through the Channel Islands (Jones and Swartz, 1987; Dohl et al., 1981, 1983;

Bonnell and Daily, 1993). The potential drill sites for

the units located north of Point Conception (Point Sal,

Purisima, and Bonito) would likely be 8 km (4 nm) or

more offshore, well beyond the main migration corridor. Migrating gray whales might be expected to pass

relatively close to the drill site on the Gato Canyon

Unit, which is located in the western Santa Barbara

Channel 5 km (2.7 nm) or more from the mainland

shore. However, the very small predicted radius of

response for semi-submersible drilling noise makes it

unlikely that any disruption of gray whale migration

would occur.

Therefore, effects on marine mammals from drilling noise associated with the proposed delineation activities are expected to be restricted to minor, temporary (less than 1-hour) disturbances within approximately 100 m of the drilling rig. These impacts are

considered to be negligible.

Vessel Traffic. Crew and supply boats are used

daily to transport personnel and supplies to platforms

offshore southern California. Support vessels for activities in the Santa Barbara Channel and Santa Maria

Basin operate out of bases in the Santa Barbara Channel; support vessels traveling to and from the four platforms in San Pedro Bay operate out of Long Beach.

The Santa Barbara Channel/Santa Maria Basin

Oil Service Vessel Traffic Corridor Program is intended

to minimize interactions between oil industry operations and commercial fishing operations. It was developed cooperatively by the two industries through

the Joint Oil/Fisheries Liaison Office (JOFLO). In

addition to providing transit corridors in and out of

area ports, the program routes support traffic along

the Channel seaward of an outer boundary line. East

of Gaviota, the outer boundary is defined by the 30-

fathom line; west of Gaviota, and north of Point Conception as far as Pedernales Point, it follows the 50-

fathom line. In the area west of Gaviota, the 50-fathom

line is 4 km (2 nm) or more offshore.

As described in section 2.4, support vessel traffic

for the proposed delineation drilling operations will

operate out of Port Hueneme, with some possible crew

boat trips originating from the Carpinteria Pier. Crew

boats will average 2-8 trips per month throughout the

approximately 14-month period of delineation drilling

activities for all four projects; a total of about 90 trips

will occur. Supply boat trips will average 8-12 per

month, for a total of approximately 148 trips over the

14 months. As the location of the delineation drilling
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activities shifts from units in the Santa Maria Basin

eastward into the western Santa Barbara Channel (i.e.,

the activities on the Bonito and Gato Canyon Units),

overall support vessel traffic will peak during the first

6 months at about 20 trips per month, then decrease

to about 10 trips per month during the final 3 months

of activity.

Additionally, fluid produced during the drill stem

test of each delineation well will be barged to Long

Beach (possibly Port Hueneme for the Bonito Unit) at

the end of the testing period. Transportation of the

barges will comply with established vessel traffic corridors. A total of 4-10 such trips is estimated to occur

over the 14-month duration of the proposed delineation drilling activities.

Vessels are the major contributors to overall

background noise in the sea (Richardson et al., 1995).

Sound levels and frequency characteristics are roughly

related to ship size and speed. The dominant sound

source is propeller cavitation, although propeller “singing,” propulsion machinery, and other sources (auxiliary machinery, flow noise, wake bubbles) also contribute. Vessel noise is a combination of narrowband

tones at specific frequencies and broadband noise. For

vessels the approximate size of crew and supply boats,

tones dominate up to about 50 Hz. Broadband components may extend up to 100 kHz, but they peak much

lower, at 50-150 Hz.

Richardson et al. (1995) give estimated source

levels of 156 dB for a 16-m crew boat (with a 90-Hz

dominant tone) and 159 dB for a 34-m twin diesel (630

Hz, 1/3 octave). Broadband source levels for small,

supply boat-sized ships (55-85 m) are about 170-180

dB. Most of the sound energy produced by vessels of

this size is at frequencies below 500 Hz. Many of the

larger commercial fishing vessels that operate off southern California fall into this class.

In general, seals often show considerable tolerance of vessels. Sea lions, in particular, are known to

tolerate close and frequent approaches by boats

(Richardson et al., 1995).

Odontocetes also often tolerate vessel traffic, but

may react at long distances if confined (e.g., in shallow water) or previously harassed (Richardson et al.,

1995). Depending on the circumstances, reactions may

vary greatly, even within species. Although the avoidance of vessels by odontocetes has been demonstrated

to result in temporary displacement, there is no evidence that long-term or permanent abandonment of

areas has occurred. Sperm whales may react to the

approach of vessels with course changes and shallow

dives (Reeves, 1992), and startle reactions have been

observed (Whitehead et al., 1990; Richardson et al.,

1995).

There have been specific studies of reactions to

vessels by several species of baleen whales, including

gray (e.g., Wyrick, 1954; Dahlheim et al., 1984; Jones

and Swartz, 1984), humpback (e.g., Bauer and

Herman, 1986; Watkins, 1986; Baker and Herman,

1989), bowhead (e.g., Richardson and Malme, 1993),

and right whales (e.g., Robinson, 1979; Payne et al.,

1983). There is limited information on other species.

Low-level sounds from distant or stationary vessels often seem to be ignored by baleen whales

(Richardson et al., 1995). The level of avoidance exhibited appears related to the speed and direction of

the approaching vessel. Observed reactions range from

slow and inconspicuous avoidance maneuvers to instantaneous and rapid evasive movements. Baleen

whales have been observed to travel several kilometers from their original position in response to a

straight-line pass by a vessel (Richardson et al., 1995).

Based on experiences in southern California, the

MMS believes that accidental collisions between endangered whales and support vessel traffic are unlikely

events. Although large cetaceans have occasionally

been struck by freighters or tankers, and sometimes

by small recreational boats, no such incidents have

been reported with crew or supply boats off California

(MMS, unpubl. data).

Pinnipeds are very nimble and considered very

unlikely to be struck by vessels. However, the single

documented instance of a collision between a marine

mammal and a support vessel involved a pinniped—

an adult male elephant seal struck and presumably

killed by a supply vessel in the Santa Barbara Channel in June 1999.

The level of support vessel and barge traffic associated with the proposed delineation activities is

expected to result in temporary (less than 1-hour),

localized disturbances to some marine mammals, primarily baleen whales. Collisions between support vessels and marine mammals, while possible, are considered to be highly unlikely events. Impacts from these

sources should be lessened by implementation of the

marine mammal avoidance guidelines specified in the

operators’ MWCP’s and described above and are expected to be negligible.

Aircraft. Offshore southern California, helicopters are a primary means of crew transport on and off

platforms, and helicopter traffic is a daily occurrence

in the Point Conception area. OCS helicopter traffic

in the Pacific OCS Region operates primarily out of

Santa Maria, Lompoc, and Santa Barbara airports.

Most of this traffic is to and from platforms in the

western Santa Barbara Channel and Santa Maria

Basin. In addition, several international and numerous smaller airports, along with several military airfields, exist along the southern California coast, and

air traffic is a daily or even hourly occurrence in the

region.

Beginning in the 1980’s, a standard Information

to Lessees (ITL) issued in conjunction with OCS lease

sales off southern California provided offshore opera-
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tors with guidelines for protecting marine mammals

and birds from aircraft (Bornholdt and Lear, 1995).

The ITL stated that,

“Aircraft should operate to reduce effects of aircraft disturbances on seabird colonies and marine

mammals, including migrating gray whales, consistent with aircraft safety, at distances from the coastline and at altitudes for specific areas identified by the

U.S. Fish and Wildlife Service (FWS), National Marine Fisheries Service (NMFS), and California Department of Fish and Game (CDFG). A minimum altitude

of 1,000 feet is recommended near the Channel Islands

Marine Sanctuary to minimize potential disturbances.

The CDFG and FWS recommend minimum altitude

restrictions over many of the colonies and rookeries.”

Although the original ITL is no longer in force,

tors in the southern Santa Maria Basin are complying with these restrictions (P. Schroeder, MMS, pers.

comm.). Air traffic over the Channel Islands National

Marine Sanctuary is restricted by Federal regulation

to altitudes greater than 1,000 ft (15 CFR

922.71(a)(5)). Vandenberg AFB also has a 1,000-ft

flight restriction over identified harbor seal haul-out

areas (N. Read, Vandenberg AFB, pers. comm.). More

recently, the 1,000-foot minimum altitude restriction

was extended to air traffic passing the vicinity of the

Santa Maria River mouth, to address concerns over

possible disturbance of marine bird nesting habitat.

These restrictions would be supplemented by the operators’ MWCP guidelines (see above), which call for

helicopters to maintain at least a 1-mile (1.6-km) distance from wildlife concentrations on shore and a minimum overflight altitude of 1,500 ft (460 m) at sea.

As described in section 2.4, helicopter trips in

support of the proposed delineation activities are expected to average 20-30 per month. Helicopters will

operate out of Santa Barbara Airport for activities in

the Bonito and Gato Canyon Units and Santa Maria

Airport for the Purisima and Point Sal Units. A total

of 354 trips are projected for the duration of the

projects.

Air-to-water transmission of sound is very complex (Richardson et al., 1995). An understanding of

underwater sound from any aircraft depends on 1) the

receiver depth, and 2) the altitude, aspect, and strength

of the source.

The concept of a one-meter sound source means

very little when discussing aircraft sound production,

and an altitude of 300 m is the usual reference distance (Richardson et al., 1995). The angle of incidence at the water surface is very important—much

incident sound is reflected at angles greater than 13

degrees from the vertical. This 26-degree “cone” of

sound is defined physically by Snell’s Law and influenced by sea conditions. Water depth and bottom conditions also strongly influence the propagation and

levels of underwater sound from passing aircraft;

propagation is attenuated in shallow water, especially

when the bottom is reflective (Richardson et al., 1995).

The rotors are the primary sources of sound from

helicopters (Richardson et al., 1995). The rotation

rate and the number of blades determine the fundamental frequencies. Fundamental frequencies are usually below 100 Hz, with most dominant tones below

500Hz. These are primarily harmonics of the main

and tail rotor blade rates, although other tones associated with engines and other rotating parts may also

be present.

Richardson et al. (1995) present an estimated

source level for a Bell 212 helicopter of about 150 dB

at altitudes of 150-600 m, with the dominant frequency

a 22-Hz tone with harmonics. Elsewhere a source level

of 165 dB is presented for broadband helicopter noise

(frequencies 45-7070 Hz).

Generally, peak received levels occur as the aircraft passes directly overhead and are directly related

to altitude and depth. However, when the aircraft is

not passing directly overhead, received levels may be

stronger at “midwater” depths. Helicopters tend to

radiate more sound forward, and duration varies with

depth. For example, a Bell 214 was audible in air for 4

minutes before passing, for 38 seconds at 3-m depth,

and for 11 seconds at 18 m.

There have been few systematic studies on the

reactions of pinnipeds to aircraft, including helicopters (Richardson et al., 1995). Most documented observations of the reactions of pinnipeds to aircraft noise

have involved animals hauled out on land. Under these

circumstances, recorded reactions range from increased

alertness to headlong rushes into the water. In open

water, pinnipeds sometimes respond to low-flying aircraft by diving (Richardson et al., 1995; M.O. Pierson,

MMS, pers. obs.).

There are no data on the received levels at which

toothed whales, or odontocetes, react to aircraft

(Richardson et al., 1995). Observed reactions include

diving, slapping the water with flukes or flippers, and

swimming away. Information on the reactions of sperm

whales to aircraft has been mixed. Sperm whales have

not been observed to exhibit obvious reactions to lowflying helicopters (Richardson et al., 1995). However,

sperm whales have been observed to dive immediately

in response to a Twin Otter passing 150-230 m overhead (Mullin et al., 1991).

Baleen whales vary in their responses to the approach of aircraft. Richardson et al. (1995; pp. 249-

252) review the recorded behavior of several baleen

whale species, including bowhead, right, gray, humpback, and minke whales. They conclude that response

depends on the whales’ activities and situations, with

foraging or socializing groups being less likely to react to the approach of aircraft than individual animals. Observed responses include hasty dives, turns,

and other changes in behavior. To date, there is no
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Delineation Drilling Activities Offshore Santa Barbara County

evidence that aircraft disturbance has resulted in longterm displacement of baleen whales.

The level of helicopter traffic associated with the

proposed delineation activities is expected to result in

temporary (less than 1-hour), localized disturbances

to some marine mammals. These impacts should be

lessened by implementation of the marine mammal

avoidance guidelines specified in the operators’

MWCP’s and described above and are expected to be

negligible.

Well Abandonment. Once the drilling and testing have been completed, each of the delineation wells

will be permanently plugged and abandoned (section

2.3). Part of the removal process involves cutting the

well casing string 5 m (15 ft) below the sea floor. Well

casing may be cut mechanically or with explosives. In

the latter case, shaped charges are lowered inside the

casing and detonated. Commonly, such charges weigh

in the range of 16-20 kg (35-45 lb) (Howorth et al.,

1996; Howorth, 1997).

Underwater explosions are the strongest manmade point sources of sound in the sea (Richardson et

al., 1995). The underwater pressure signature of a

detonating explosion is composed of an initial shock

wave, followed by a succession of oscillating bubble

pulses (if the explosion is deep enough not to vent

through the surface) (Urich, 1983; Richardson et al.,

1995). Pulse rise time is very brief (within about a

microsecond). The shock wave is a compression wave

that expands radially out from the detonation point of

an explosion. The wave is supersonic, but is quickly

reduced to normal acoustic waves (Twachtman Snyder

& Byrd, Inc., 2000). The broadband source level of a

20-kg charge is about 279 dB re 1 μPa, with dominant

frequencies below 50 Hz (Richardson et al., 1995).

It has been shown that nearby underwater blasts

can injure or kill marine mammals (Richardson et al.,

1995). Although pinnipeds, odontocetes, and baleen

whales are all known to have been killed by underwater explosives, threshold levels for injury or death are

not well established (Fitch and Young, 1948; Ketten et

al., 1993; Richardson et al., 1995). In general, damage tends to occur at boundaries between tissues of

different densities, with gas-containing organs (such

as lungs and intestines) and the auditory system being especially susceptible.

 Young (1991) calculated safe distances for several marine animals from underwater explosions of

various sizes. These calculations were for open-water

blasts and did not account for the dampening effects

that would occur if a charge were detonated 5 m below

the sea floor. For an approximately 23-kg (50-lb)

charge, the estimated safety distances were 530 m

(1,750 ft) for odontocetes and 300 m (1,000 ft) for baleen whales.

Richardson et al. (1995) summarize available

information on the reported behavioral reactions of

marine mammals to underwater explosions. Experience with the use of seal bombs as scare charges indicates that pinnipeds rapidly habituate to and, in general, appear quite tolerant of noise pulses from explosives. Whether hearing damage or other injuries have

occurred during these situations is unknown. Likewise, little success has been demonstrated in the use

of scare charges to repel odontocetes. An example is

the attempted use of seal bombs to move bottlenose

dolphins away from platform abandonment areas where

larger demolition blasts are about to occur (Klima et

al, 1988).

There are few data on the reactions of baleen

whales to underwater explosions. Gray whales were

apparently unaffected by 9- to 36-kg charges used for

seismic exploration (Fitch and Young, 1948). However, Gilmore (1978) felt that similar underwater blasts

within a few kilometers of the gray whale migration

corridor did “sometimes” interrupt migration. In

Newfoundland, humpbacks displayed no overt reactions within about 2 kilometers of 200- to 2,000-kg

explosions. Whether habituation and/or hearing damage occurred was unknown, but at least two whales

were injured (and probably killed) (Ketten et al., 1993).

As previously stated, the use of explosives for

delineation well abandonment would involve the detonation of a relatively small, 16- to 20-kg charge in the

well casing 5 m below the sea floor. This positioning

of the charge would dampen the explosion and restrict

shock and acoustic effects primarily to the area of water

immediately above the well head. However, a marine

mammal close to the detonation site potentially could

be injured or killed, or suffer permanent or temporary

hearing damage. Some disturbance of marine mammals present in the vicinity of the detonation area could

also occur, but these would be expected to be minor

and temporary (less than 1 hour in duration). Overall, impacts from this source are expected to be low.

These impacts could be further reduced through the

implementation of a wildlife mitigation plan designed

to minimize impacts on marine mammals and other

marine animals (see Mitigation MM1, below).

Effluent Discharges. The potential effects of OCS

discharges on marine mammals include 1) direct toxicity (acute or sublethal), through exposure in the

waters or ingestion of prey that have bioaccumulated

pollutants; and 2) a reduction in prey through direct

or indirect mortality or habitat alteration caused by

the deposition of muds and cuttings (SAIC, 2000a, b).

However, there is no toxicity information on the effects of muds and cuttings and produced-water discharges on marine mammals. Comprehensive reviews

by the National Academy of Sciences (1983), the U.S.

Environmental Protection Agency (1985), and Neff

(1987) do not address the potential effects of OCS discharges on these groups of animals (MMS, 1996). Significant impacts from OCS discharges have not been
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Environmental Consequences, Cumulative Impacts (2002 - 2006), and Mitigation Measures

associated with marine mammals, because they are

highly mobile and capable of avoiding such discharge,

and their ranges far exceed the extent of the discharge

plume.

The EPA biological assessment for the proposed

reissuance of its general NPDES permit for offshore

OCS facilities in southern California waters concludes

that direct toxicity to listed marine mammals, or their

food base, should be minimal (SAIC, 2000a, b). All

such discharges are required to meet NPDES water

quality criteria, which were established to protect biological resources outside the mixing zone. Therefore,

any contact with OCS discharges likely would be extremely limited. No effects to marine mammals in the

project area from effluent discharges associated with

the proposed delineation wells are expected.

5.2.8.1.1 SUMMARY AND CONCLUSIONS

In summary, effects to marine mammals from

noise and disturbance resulting from most activities

associated with the Proposed Action, including drilling, support vessel and barge traffic, helicopter traffic, and delineation well abandonment, are expected

to be restricted to temporary (less than 1-hour), localized disturbances. These impacts are considered to be

negligible. The use of explosives for delineation well

abandonment also raises the possibility that a marine

mammal could be killed, injured, or suffer hearing

damage. Overall, impacts from this source are expected

to be low and could be further reduced through mitigation (see Mitigation MM1, below).

Overall, activities associated with the proposed

delineation activities are expected to cause negligible

to low impacts to marine mammals in the project area.

These impacts would be common to all units and would

remain the same for all units combined.

5.2.8.1.2 MITIGATION MEASURES FOR

IMPACTS FROM THE PROPOSED

ACTION

Mitigation MM1 (Explosive Subsea Removal): Avoiding impacts to marine mammals and sea

turtles from the use of explosives for well and platform abandonment on the Pacific OCS would require

implementation of a wildlife mitigation plan similar

to those employed for platform removal in California

State waters (Howorth, 1997) and in the MMS Gulf of

Mexico OCS Region (NTL 99-G21). Typically, such a

plan has included the use of shipboard observers or

divers (possibly supplemented by aerial surveys), the

establishment of a safety zone around the detonation

site, and monitoring of the zone to ensure that no

animals are present when the charge is detonated.

Implementation of this mitigation would make

it unlikely that any marine mammal injury or mortality would occur as a result of well abandonment operations associated with the proposed delineation activities. Since 1986, during explosive removals of offshore platforms in the Gulf of Mexico (where a 915-m

safety zone is employed), no confirmed marine mammal blast injuries or mortality have been reported.

Impacts to marine mammals would be negligible.

5.2.8.2 CUMULATIVE IMPACT ANALYSIS

FOR MARINE MAMMALS (2002-2006)

Cumulative Impacts without the Proposed

Action: Section 5.1.2 describes the projects considered in the cumulative analysis for the proposed delineation activities. Possible sources of cumulative impacts in the project area include on-going and proposed oil and gas activities in Federal and State waters, Alaskan and foreign-import tankering, and military operations. Cumulative impacts to marine mammals may also occur from commercial fishing operations, shipping activities, and other anthropogenic and

non-anthropogenic sources.

The projects discussed in this section include

past, present, and foreseeable actions that may produce impacts during 2002-2006, the expected duration

of the proposed delineation activities. Potential cumulative impacts are discussed below.

Offshore Oil and Gas Activities. Section 4.0 describes the offshore oil and gas activities that may

result in impacts to marine mammals. These include

geophysical surveys, construction, drilling and production activities with associated support activities,

and the abandonment, or decommissioning, of wells

and offshore facilities. As discussed in section 5.2.1,

the major impact agents expected from these proposed

activities are noise and disturbance. The potential

use of explosives in the abandonment of wells and offshore platforms also raises the possibility of lethal

impacts to marine mammals.

Section 5.2.8.1 discusses the potential impacts

to marine mammals from offshore oil and gas activities including well drilling, support vessel and helicopter traffic, and well abandonment. The potential

impacts from geophysical surveys, construction, and

platform-based development and production operations

are discussed below.

Geophysical Surveys. Section 4.0 describes past

geological and geophysical survey activities in the

Pacific OCS Region. Since 1963, more than 400 geological and geophysical surveys, including both 2-D

and 3-D seismic surveys, have been conducted in the

Santa Barbara Channel and Santa Maria Basin (tables

4.0.1-2 and 4.0.1-3), and many others have occurred

in State waters. Most of these surveys occurred during the 1970’s and 1980’s; the most recent seismic

survey offshore southern California was an Exxon 3-

D seismic survey conducted in the western Santa Barbara Channel in 1995 (MMS, 1995). No Pacific OCS
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operators have approached MMS with proposals to

conduct such surveys to date, although additional 2-

D or 3-D seismic surveys may occur during the next

few years.

The potential impacts to marine mammals from

the intense, low-frequency sounds produced by the

airguns used to conduct offshore seismic surveys have

become the focus of increasing concern in recent years

(Malme et al., 1983, 1984; Turnpenny and Nedwell,

1994; Richardson et al., 1995; HESS, 1999;

McCaughley et al., 2000; Pierson et al., 2001).

Richardson et al. (1995) provide a detailed review of

the available information. In summary, based on available information (Richardson et al., 1995; McCaughley

et al., 2000), marine mammals would have to be very

close to an operating airgun array, probably within

100 m, to be at risk of temporary or permanent hearing damage. The most likely effect of seismic surveys

on marine mammals is short-term avoidance behavior. Data on the reactions of pinnipeds and odontocetes

to seismic noise are relatively limited and inconclusive; however, some brief and localized avoidance responses from these small marine mammals could occur. Baleen whales are known to react to seismic survey noise and would be expected to display the most

overt behavioral reactions, including active avoidance

and changes in respiration and diving patterns. Based

on information from field studies, the baleen whales

in the vicinity of a seismic survey area would be likely

to react at distances of 5-8 km (2.5-4 nm) or more

from an airgun array.

Construction. As described in section 4.0, construction activities include the installation of platform

jackets and topsides, the laying of pipelines, platform

hook-up and commissioning, and the initiation of drilling. From 1967 to 1992, 19 OCS platforms and associated pipelines were installed in the Santa Barbara

Channel and Santa Maria Basin (table 4.0.1-6). All of

these platforms are still in place. Seven offshore platforms were installed in State waters in this area between 1958 and 1966, but only one, Platform Holly

near Goleta, remains. No new offshore construction

is expected to occur during the 2002-2006 duration of

the proposed delineation activities.

Very little information exists on the noise produced by offshore construction activities. Most of the

studies of marine construction noise have dealt with

the construction of offshore oil industry facilities in

shallow arctic waters and have focused on marine

dredging (Richardson et al., 1995). These operations

can be strong sources of continuous noise in nearshore

waters. Broadband source levels of 172-185 dB re 1

:Pa-m have been recorded for dredging activities

(Richardson et al., 1995). Although some higher frequency tones are produced, most of the energy is low

frequency, below about 1,000 Hz, and dredge noise is

usually undetectable in shallow water at ranges beyond 20-25 km.

The effects of dredging and other construction

activities on marine mammals have received little study

(Richardson et al., 1995). Pile-driving activities at a

platform construction site in the Santa Barbara Channel had no apparent effect on the behavior of dolphins

passing at an average distance of 3.5-4.3 km (1.9-2.3

nm) (Dames and Moore, 1990). In two instances, migrating gray whales that were passing 5-8 km (3-4

nm) from the same platform construction site in the

Santa Barbara Channel were not observed to react to

pile-driving activities (Dames and Moore, 1990). There

are observations from studies in the Arctic indicating

that belugas and bowhead whales may tolerate considerable dredge noise, but are more sensitive to moving tug-dredge combinations than to stationary

dredges (Malme et al., 1989). In one experimental

study of bowhead whales (Richardson et al., 1990b),

whales exposed to recorded dredge noise at received

levels of 122-131 dB re 1 Pa (21-30 dB above ambient)

exhibited avoidance by stopping feeding and moving

away from within 0.8 km (0.4 nm) of the sound projector to locations more than 2 km (1 nm) away. However, there is some evidence of habituation by bowhead whales to actual dredging activity (Richardson

et al., 1995).

Migrating gray whales were monitored during

an offshore pipeline construction project in the Santa

Barbara Channel in 1991-1992 (Woodhouse and

Howorth, 1992). The lack of baseline data made it

impossible to determine whether gray whale migration pathways were altered. However, hundreds of

whales did move through the project area on both the

southbound and northbound legs of their migration,

and although some animals appeared to make local

course changes around construction activities, the

authors found no evidence that gray whales were deterred in their migration activity by the construction.

In general, marine mammal reactions to construction

activities would likely involve temporary avoidance

behavior at distances of 2 km (1 nm) or less from the

operations.

Development and Production. Section 4.0 describes offshore development and production activities

in the Pacific OCS Region. There currently are 23

offshore platforms in the Pacific OCS Region (table

4.0.1-5). Of these, 4 are in the Santa Maria Basin, 15

are in the Santa Barbara Channel, and 4 are in San

Pedro Bay. As of February 2001, more than 1,200 wells

had been drilled in the Pacific OCS Region. This number includes 890 oil and gas development wells drilled

from platforms and 326 exploratory wells drilled from

a variety of rigs, including mobile offshore drilling units

(MODU’s), jack-ups, barges, and drill ships. Currently, based on data from 1996 through 1999, slightly

less than 2 development wells per month are begun

from Region platforms. No exploratory wells have been

drilled in the Pacific OCS Region since 1989.
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Environmental Consequences, Cumulative Impacts (2002 - 2006), and Mitigation Measures

Section 5.2.8.1 discusses the sound levels produced by semi-submersible drilling rigs and the potential impacts to marine mammals. The sound levels

produced by drilling from conventional, bottomfounded platforms are relatively low and are similar

to levels generated by production activities (Gales,

1982; Richardson et al., 1995). Gales (1982) recorded

noise produced by one drilling and three drilling and

production platforms off California. The noises produced were so weak that they were nearly undetectable even alongside the platform in sea states of Beaufort 3 or better. No source levels were computed, but

the strongest received tones were very low frequency,

about 5 Hz, at 119-127 dB re 1 mPa. The highest

frequencies recorded were at about 1.2 kHz.

Richardson et al. (1995) predict that the radii of audibility for baleen whales for production platform noise

would be about 2.5 km (1.3 nm) in nearshore waters

and 2 km (1 nm) near the shelf break.

For gray whales off the coast of central California, Malme et al. (1984) recorded a 50-percent response

threshold to playbacks of drilling noise at 123 dB re 1

mPa (and about 117 dB re 1 mPa in the 1/3-octave

band). This is well within 100 m (330 ft) in both

nearshore and shelf-break waters; therefore, the predicted radius of response for grays, and probably other

baleen whales as well, would also be less than 100 m.

Richardson et al. (1995) predicted similar radii of response for odontocetes and pinnipeds.

Vessel Traffic. Section 4.0 discusses crew and

supply boat operations in the Pacific OCS Region.

Current levels of support vessel traffic for offshore

platforms in both Federal and State waters are presented in table 4.0.1-6. Support of development and

production activities in the eastern and central Santa

Barbara Channel primarily involves crew and supply

boats. Crew changes for platforms in the Santa Maria

Basin are conducted by helicopter (see discussion in

next section), resulting in lower levels of support boat

traffic. In the Channel and Basin, approximately 90-

140 crew boat and 10-12 supply boat trips are made

each week. An additional 25 crew boat trips are made

each week to State Platform Holly. Support vessels

operate out of Port Hueneme, Ventura Harbor,

Carpinteria Pier, or Ellwood Pier. It should be noted

that many of these trips, particularly to the platforms

off Carpinteria, are relatively short and that many trips

may service more than one platform.

Section 5.2.8.1 discusses the sound levels produced by support vessels and the potential impacts to

marine mammals. As discussed in section 5.0, the highest levels of support vessel traffic to a platform may be

expected during the construction phase. During this

phase, crew boat trips may occur as often as three

times per day and supply boat trips twice per day for

brief periods (table 4.0.1-7).

As discussed in section 5.2.8.1, the continued

levels of support vessel traffic associated with offshore

oil and gas activities in the project area are expected

to result in temporary (less than 1-hour), localized

disturbances to some marine mammals, primarily baleen whales. Collisions between support vessels and

marine mammals, while possible, are considered to be

highly unlikely events.

Aircraft. Section 4.0 discusses support helicopter operations in the Pacific OCS Region. Current

levels of support helicopter traffic for offshore platforms in both Federal and State waters are presented

in table 4.0.1-6. As discussed in section 4.0, the highest levels of support helicopter traffic to a platform

may be expected during the construction phase. During this phase, helicopter trips to a single platform

may occur as often as 7 times per day for brief periods

(table 4.0.1-7). Support helicopter traffic is confined

to platforms in the western Santa Barbara Channel

and Santa Maria Basin, where 6-8 helicopter trips occur per day. These flights originate from the Santa

Barbara and Santa Maria airports.

Section 5.2.8.1 discusses the sound levels produced by helicopters and the potential impacts to marine mammals. The levels of helicopter traffic associated with offshore oil and gas activities in the project

area are expected to result in temporary (less than 1-

hour), localized disturbances to some marine mammals.

Offshore Facility Decommissioning. Section

5.2.8.1 discusses the process of exploratory well abandonment and the associated potential impacts to marine mammals. Section 4.0 describes the processes

involved in decommissioning offshore facilities. For

purposes of analysis, it is assumed that decommissioning would encompass the complete removal of a platform and associated pipelines, with none of the leg

structure left in place to form an artificial reef. To

date, only one facility in the Pacific OCS Region has

been decommissioned—the Offshore Storage and Treatment (OS&T) vessel that formerly served the Santa

Ynez Unit platforms in the Santa Barbara Channel.

In addition, six offshore platforms in State waters in

the Channel have been removed—two in 1988 and four

in 1996 (table 4.0.1-6). No offshore decommissioning

activities are expected to occur in either Federal or

State waters during the 2002-2006 duration of the proposed delineation activities.

Oil Spills. No oil spills are expected to result

from the Proposed Action. As discussed in section

5.1.3, the cumulative oil spill risk for the project area

results from several sources: ongoing and projected

oil and gas production from existing OCS facilities in

the Santa Barbara Channel and Santa Maria Basin,

several proposed development projects on the Federal

OCS, ongoing production from one facility in State

waters in the Santa Barbara Channel, two reasonably
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Delineation Drilling Activities Offshore Santa Barbara County

foreseeable oil and gas projects in State waters, and

the tankering of Alaskan and foreign-import oil

through area waters. Tables 5.1.3.1-2 and 5.1.3.1-3

present the estimated mean number of spills of various sizes and the probability of their occurrence as a

result of the described activities.

The most likely oil spill scenario for existing and

proposed offshore oil and gas activities is that one or

more oil spills in the 50-1,000-bbl range would occur

over the period 2002-2006, and that such a spill would

most likely be 200 bbl or less in volume. The probability that one or more spills of this size will occur

this period is 75.9 percent (table 5.1.3.1-2). The maximum reasonably foreseeable oil spill volume from future offshore oil and gas activities is 2,000 bbl, assumed for purposes of analysis to be a pipeline spill.

The probability of a spill of this size occurring during

the period 2002-2006 is 23.3 percent (table 5.1.3.1-3).

Based on data from tanker spills in U.S. waters, the

mean size for a tanker spill is assumed to be 22,800

bbl (with a probability of occurrence of 99 percent for

this period; table 5.1.3.1-3). The rationale for these

estimated spill sizes is presented in section 5.1.3. The

potential impacts to marine mammals in the project

area from spills of each of these three sizes are discussed below.

The level of impacts from such spills will depend

on many factors, including the type, rate, and volume

of oil spilled and the weather and oceanographic conditions at the time of the spill. These parameters would

determine the quantity of oil that is dispersed into the

water column; the degree of weathering, evaporation,

and dispersion of the oil before it contacts a shoreline;

the actual amount, concentration, and composition of

the oil at the time of shoreline or habitat contact; and

a measure of the toxicity of the oil.

Marine mammals vary in their susceptibility to

the effects of oiling (Geraci and St. Aubin, 1990; Williams, 1990; Loughlin, 1994a). Oil may affect marine

mammals through various pathways: surface contact,

oil inhalation, oil ingestion, and baleen fouling (Geraci

and St. Aubin, 1990). Cetaceans risk a number of

toxic effects from accidental oil spills at sea (Geraci,

1990). Since cetaceans (like most adult pinnipeds) rely

on layers of body fat and vascular control rather than

pelage to retain body heat, they are generally resistant to the thermal stresses associated with oil contact. However, exposure to oil can cause damage to

skin, mucous, and eye tissues. The membranes of the

eyes, mouth, and respiratory tract can be irritated and

damaged by light oil fractions and the resulting vapors. If oil compounds are absorbed into the circulatory system, they attack the liver, nervous system,

and blood-forming tissues. Oil can collect in baleen

plates, temporarily obstructing the flow of water between the plates and thereby reducing feeding efficiency. Reduction of food sources from acute or chronic

hydrocarbon pollution could be an indirect effect of

oil and gas activities.

It has been suggested that cetaceans could consume damaging quantities of oil while feeding, although Geraci (1990) believes it is unlikely that a

whale or dolphin would ingest much floating oil. However, during the Exxon Valdez oil spill in 1989, killer

whales were not observed to avoid oiled sections of

Prince William Sound, and the potential existed for

them to consume oil or oiled prey (Matkin et al., 1994).

Fourteen whales disappeared from one of the resident

pods in 1989-90, and although there was spatial and

temporal correlation between the loss of whales and

the spill, no clear cause-and-effect relationship was

established (Dahlheim and Matkin, 1994). Fin, humpback, and gray whales were observed entering areas

of the Sound and nearby waters with oil and swimming and behaving normally; no mortality involving

these species was documented (Harvey and Dahlheim,

1994; Loughlin, 1994b; von Ziegesar et al., 1994;

Loughlin et al., 1996).

Baleen whales in the vicinity of a spill may ingest oil-contaminated food (especially zooplankters,

which actively consume oil particles) (Geraci, 1990).

However, since the principal prey of most baleen whales

(euphausiids and copepods) have a patchy distribution and a high turnover rate, an oil spill would have

to persist over a very large area to have more than a

local, temporary effect.

Since oil can destroy the insulating qualities of

hair or fur, resulting in hypothermia, marine mammals that depend on hair or fur for insulation are most

likely to suffer mortality from exposure (Geraci and

St. Aubin, 1990). Most vulnerable to the direct effects

of oiling among the pinnipeds are fur seals and newborn pups, which lack a thick insulating layer of fat

(see section 5.2.9.2 for a discussion of oil spill impacts

on sea otters). Frost et al. (1994) estimated that more

than 300 harbor seals died in Prince William Sound

as a result of the Exxon Valdez oil spill and concluded

that pup production and survival were also affected.

Indeed, the majority of the dead harbor seals recovered were pups (Spraker et al., 1994). It should also

be noted, however, that this mortality estimate has

been questioned (Hoover-Miller et al., 2001). In contrast, although Steller sea lions and their rookeries

in the area were exposed to oil, none of the data collected provided conclusive evidence of an effect on their

population (Calkins et al., 1994).

As stated above, it is assumed that the most likely

size for a spill occurring from offshore oil and gas activities in the Pacific OCS Region is 200 bbl or less. If

a spill of this size were to occur in the Santa Barbara

Channel or Santa Maria Basin, it could contact the

mainland shoreline or one of the northern Channel

Islands. The largest aggregations of marine mammals

in this area are found on San Miguel Island, which is
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Environmental Consequences, Cumulative Impacts (2002 - 2006), and Mitigation Measures

at the western end of the chain and is part of the Channel Islands National Marine Sanctuary and National

Park (section 4.6.9). However, San Miguel is approximately 40 km (20 nm) from Platform Heritage, the

nearest offshore facility. A 200-bbl spill would be unlikely to reach the island and would not be considered

a threat to marine mammals on San Miguel.

Data from moored current meters and surfacedrifter trajectory observations (section 5.1.3) indicate

that north of Point Conception a spill could move northward along the mainland coast, typically during relaxation current events when the wind is low. Individual drifters made landfall along the coast as far

north as Point Lobos within 10 days. However, when

averaged over all flow regimes, the most likely northern limit of shoreline spill contact is Ragged Point,

near the southern end of the Big Sur coast and within

the Monterey Bay National Marine Sanctuary (section 4.6.9).

Thus, it is possible that a 200-bbl spill would

contact the shoreline in this area, although probably

well south of Ragged Point. Predicting the length of

coastline affected by an oil spill that comes ashore is

extremely difficult due to the complexity of the transport process, which depends on factors such as

nearshore wind patterns and currents, coastal bathymetry, tidal movements, and turbulent flow processes.

Using historical data on marine spills, Ford (Ford,

1985; Ford and Bonnell, 1987) devised a model to simulate the length of coastline that could be contaminated.

A recent assessment of the potential impact of oil spills

on California sea otters by Brody et al. (1996) provides support for the general validity of the Ford model.

Based on the multiple regression equations developed by Ford, a 200-bbl spill would be expected to

oil a mean stretch of 4-5 km (2-3 nm) of shoreline (Ford,

1985). The model further predicts a 95-percent probability that a 200-bbl spill reaching shore would contact a length of coastline greater than 1 km (0.5 nm)

and a 5-percent probability that it would contact a

length of shoreline greater than about 19 km (10 nm).

Based on experience with past spills, continuous contact along such a length of shoreline would be unlikely. Rapid spill response (see section 5.1.3) would

further limit shoreline contact.

Seasonally, the most vulnerable marine mammal

resources along the coast between Point Conception

and Ragged Point would be harbor seal hauling areas

and pupping beaches during early spring. Harbor seal

pups are very precocial and may enter the water soon

after birth (Hoover, 1988; Riedman, 1990). In addition, harbor seal females may return to the water several times per day between nursing bouts, increasing

opportunities for repeated contact with oil (McLaren,

1990). Northern elephant seals, which breed and pup

on a rookery near Point Piedras Blancas during the

winter, are considered less susceptible to the effects of

oiling, given their larger size and the fact that females

and pups remain ashore throughout the lactation period (Le Boeuf, 1971; McLaren, 1990; St. Aubin, 1990).

If a 200-bbl spill were to contact a harbor seal

haul-out in this area, a few animals could be oiled.

The Exxon Valdez oil spill demonstrated that harbor

seals are susceptible to the effects of oiling (Frost et

al., 1994; Lowry et al., 1994; Hoover-Miller et al.,

2001). However, based on experience with past spills

of this size in this general area (e.g., the 1997 Torch

pipeline spill), it is doubtful that a spill of this size

would result in mortality.

It is also unlikely that a 200-bbl spill would have

more than a negligible impact on pinniped or cetacean

populations at sea in the project area. As discussed in

the 1984 EIR/EIS for development of the Point Arguello

Unit (ADL, 1984), likely impacts could involve the

oiling of a few individuals and/or temporary displacement from small areas of the western Santa Barbara

Channel or southern Santa Maria Basin.

As stated above, the most likely maximum size

of a major oil spill from future oil and gas development—the maximum reasonably foreseeable oil spill

volume—is 2,000 bbl. A 2,000-bbl oil spill in this area

could have more serious impacts on marine mammals,

including longer-term displacement and some mortality. Based on the Ford model, a 2,000-bbl spill would

be expected to oil a mean stretch of about 12 km (6

nm) of shoreline (Ford, 1985). The model further predicts a 95-percent probability that a 2,000-bbl spill

reaching shore would contact a length of coastline

greater than 3 km (1.5 nm) and a 5-percent probability that it would contact a length of shoreline greater

than about 52 km (28 nm).

Again, the species most likely to be affected would

be harbor seals. A 2,000-bbl spill could cause some

pup mortality if it oiled harbor seal pupping beaches

during the early spring. Elephant seals might also

suffer some pup mortality if their rookery were contacted. Overall, impacts to marine mammals from a

spill of this volume would be expected to be low.

Marine Tankers. As discussed in section 5.1.3,

none of the oil produced on the Pacific OCS is transported by tanker. However, the tankering of foreign

and Alaskan oil along the U.S. west coast does present

an oil spill risk. The effects of a 22,800-bbl tanker

spill on marine mammals in the project area potentially could be much more serious. Based on the Ford

model, a 22,800-bbl spill would be expected to oil a

mean stretch of about 39 km (21 nm) of shoreline

(Ford, 1985). The model further predicts a 95-percent

probability that a 22,800-bbl spill reaching shore would

contact a length of coastline greater than 9 km (5 nm)

and a 5-percent probability that it would contact a

length of shoreline greater than about 161 km (87 nm).

This may be somewhat of an overestimate, since U.S.-

flagged oil tankers are now voluntarily transiting the
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Delineation Drilling Activities Offshore Santa Barbara County

coast north of Point Conception at distances of 90 km

(50 nm) or more offshore, and a tanker spill in this

area would likely occur relatively far from shore.

The effects of a tanker spill of this size on marine mammals would be most serious if the spill were

to contact sensitive shoreline areas. As discussed

above, northern fur seals depend on their dense underfur for insulation and thus are very vulnerable to

the thermal effects of oiling. If a spill of this volume

were to contact the fur seal rookery on Castle Rock

off San Miguel Island during the summer breeding

season, considerable adult and pup mortality could

ensue. California sea lions, which breed nearby at

Point Bennett on San Miguel, might also suffer some

pup mortality. Local impacts to pinniped populations

could range from moderate to high.

Although, as discussed above, cetaceans are considered to be less vulnerable to the effects of oiling

than pinnipeds (Geraci, 1990; Würsig, 1990), a 22,800-

bbl tanker spill would probably have some effect on

cetaceans in the project area. Gray whales do relatively little feeding along the migration route (Oliver

et al., 1983; Nerini, 1984); based on experience with

the 1969 Santa Barbara spill (Battelle Memorial Institute, 1969; Geraci, 1990), a spill of this size would not

be likely to disrupt the gray whale migration through

the project area. (Potential impacts on endangered

baleen whales are discussed in section 5.2.9.2.)

Although Würsig (1990) believes that odontocetes

in general are too mobile and wide-ranging to be much

threatened by oil, he does think that harbor porpoises

may be at greater risk from oil spills than other

odontocetes due to their restricted nearshore habitat.

The same may be true of the nearshore California population of bottlenose dolphins. Densities of these two

species are low in project area waters (Bonnell and

Dailey, 1993; Forney et al., 2000), and it is considered

unlikely that mortality would occur. However, it is

unclear whether either of these species would avoid

oiled areas (see Smultea and Würsig, 1995), and a substantial portion of their nearshore foraging habitat

could be affected by a spill of this size. This could

increase the potential for indirect effects, such as

through the consumption of oiled prey. Impacts on

nearshore odontocetes would be expected to be low.

Military Activities. Military operations that may

have offshore impacts in the project area include those

conducted from NAS Point Mugu and Vandenberg AFB

(section 4.14). A recent draft EIS (U.S. Navy, 2000)

analyzes the potential impacts of ongoing and proposed

military activities in the U.S. Navy’s Point Mugu Sea

Range, which occupies a broad expanse of offshore

waters in the Southern California Bight and Santa

Maria Basin (figure 4.14-1). Navy activities in the

Sea Range include vessel, aircraft, and missile operations. The EIS concludes that impacts to marine mammals would be less than significant and limited to shortterm hearing effects for small numbers of marine mammals and some disturbance to pinnipeds hauled-out

on San Nicolas Island.

Vandenberg AFB is located on the central coast

between Point Arguello and Point Sal. The Air Force’s

primary missions at Vandenberg are launching and

tracking satellites in space and testing and evaluating missile systems (U.S. Navy, 2000). These operations periodically result in temporary disturbance to

marine mammals, particularly harbor seals, along the

nearby shoreline (Thorson et al., 1998). Although the

effect of launch noise on pinniped hearing is unknown,

limited experimental evidence suggests that pinnipeds

exposed to sonic booms produced by missiles in flight

may be at risk of temporary hearing threshold shifts

(Stewart et al., 1996; Thorson et al., 1998).

In addition, the U.S. Navy is developing a new

sonar system to improve its antisubmarine warfare

(ASW) capabilities. The Navy proposes to deploy up

to four Surveillance Towed Array Sensor System Low

Frequency Active (SURTASS LFA) sonar systems

worldwide for use in training, testing, and military

operations. The high source levels and low frequencies (100-500 Hz) employed in this system have raised

concerns over potential noise-related impacts to marine mammals. In response, the Navy has prepared

an EIS (U.S. Navy, 2001) to analyze the potential impacts of the Proposed Action and has developed several mitigation and monitoring measures. These include limiting operations in coastal waters to prevent

sound pressure levels of 180 dB greater from occurring within 22 km (12 nm) of land. Monitoring during LFA sonar operations would involve visual monitoring for marine mammals and sea turtles during

daylight hours by trained personnel, plus both passive and active acoustic monitoring.

Given these measures and the small number of

systems to be deployed worldwide, the Navy has concluded that the potential impacts on any stock of marine mammals from injury would be negligible and effects from significant change in a biologically significant behavior would be minimal. However, since the

potential for incidental take of marine mammals does

exist, the Navy is requesting a Letter of Authorization from NMFS.

Commercial Fisheries. Marine mammals are

taken incidentally in a number of commercial fisheries along the U.S. west coast. Off California, greatest

mortality in recent years has been recorded in the

nearshore set gillnet and offshore drift gillnet fisheries (Barlow et al., 1998; Ferraro et al., 2000; Forney

et al., 2000). However, marine mammal entanglement

rates in the drift gillnet fishery have dropped substantially since a Take Reduction Plan involving the use

of pingers was implemented in 1997 (Barlow and

Cameron, 1999; Forney et al., 2000). The set gillnet

fishery also has undergone changes and redistribu-
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Environmental Consequences, Cumulative Impacts (2002 - 2006), and Mitigation Measures

tion of effort since 1994 (Forney et al., 2000). Other

fisheries in which marine mammal mortality has been

documented include the offshore groundfish trawl fisheries, purse seine fisheries for squid and other species, troll fisheries for salmon and other species, the

salmon net pen fishery, and the commercial passenger

fishing vessel industry (Forney et al., 2000).

The minimum total fisheries-related take of California or west coast marine mammals currently appears to be more than 1,500 animals per year (Barlow

et al., 1998; Ferraro et al., 2000; Forney et al., 2000).

More than 1,000 of these are taken in the California

angel shark/halibut set gillnet fishery. Most of the

remainder are taken in the California-Oregon thresher

shark/swordfish drift gillnet fisheries.

Most of this mortality involves pinnipeds and

small cetaceans. More than 72 percent (>1,200) of

the marine mammals taken are California sea lions;

other pinniped species, including harbor seals, northern elephant seals, and a few Steller sea lions, account

for about 14 percent (>250). Small cetaceans represent nearly 10 percent of the average annual take. The

species most frequently involved include short-beaked

common dolphin, harbor porpoise, northern right

whale dolphin, Dall’s porpoise, Pacific white-sided dolphin, and Risso’s dolphin, but almost all cetacean species that occur in this area have experienced fisheryrelated mortality.

Of these, only the incidental take of harbor porpoises is of concern at the stock level. Harbor porpoise mortality is largely limited to the halibut set

gillnet fishery in central California, where fishing effort has approximately doubled since 1995 (with the

majority of recent effort in southern Monterey Bay)

(Forney et al, 2000). Entanglement rates apparently

have increased substantially since the early 1990’s,

and the estimated mean annual take for recent years

(63) is above the calculated Potential Biological Removal (PBR) for the central California stock (42 per

year) (Forney et al., 2000).

Although some mortality of large whales may

occur (Heyning and Lewis, 1990; Mazzuca et al., 1998),

large rorquals (such as blue and fin whales) are reported to be capable of swimming through nets without entangling (Forney et al., 2000). Because of their

nearshore migration route, gray whales may be somewhat more susceptible to fisheries-related mortality

than other large whales. In the 1990’s, three gray

whale mortalities were reported from the CaliforniaOregon thresher shark/swordfish drift gillnet fishery

and Makah Tribal set gillnet fishery in Washington

State (Ferraro et al., 2000). Using these and other

data, Ferraro et al. (2000) estimated a minimum annual fisheries mortality rate of 6.0 for the gray whale.

They concluded that these mortalities are likely below

10 percent of the PBR and therefore can be considered

insignificant.

Other Anthropogenic Sources of Impacts. Ship

strikes are a recognized source of whale mortality.

Eleven species are known to have been hit, including

fin (the most frequently recorded), right, humpback,

sperm, gray and minke whales (Laist et al., 2001).

Most lethal or severe injuries to whales appear to be

caused by ships measuring 80 m (260 ft) or more in

length and travelling at speeds of 26 kph (14 kts) or

greater (Laist et al., 2001).

As is the case with fisheries-related mortality (see

above), the gray whale’s nearshore migration may

increase the potential for collision with ships (Rugh

et al., 1999); five gray whale mortalities from ship

strikes were recorded off California from 1993 to 1995

(Ferraro et al., 2000). Ferraro et al. (2000) consider

this annual mortality rate of one to two gray whales

per year to be a minimum estimate.

 Although vessel strikes of the smaller toothed

whales are rarely observed, one killer whale ship-strike

mortality was recorded in the Bering Sea ground fish

trawl fishery in 1998 (Forney et al., 2000).

Pinnipeds, including California sea lions, harbor seals, and northern elephant seals, are occasionally killed in collisions with boats. As discussed in

section 5.2.8.1, the single reported collision between

an oil industry support vessel and a marine mammal

off southern California involved an elephant seal.

Other sources of human-related pinniped mortality in

California include shooting, entrainment in power

plants, and entanglement in marine debris.

For cetaceans, especially baleen whales such as

the gray whale, an additional source of potential impact is the whale-watching industry. Whale-watching

boats attempt to approach whales as closely as possible, creating a potential for disturbance and displacement from essential habitat. In California, this is a

major, seasonal industry—in the 1996-1997 season,

more than 40,000 people took part on six Los Angelesbased boats alone (Rugh et al., 1999). Although whalewatching guidelines specify a minimum approach of

100 yards (or 100 m) and recommend that boats approach whales from the rear and avoid separating cowcalf pairs, there is little enforcement. Private boats,

including jetskis, are a serious problem; at times, 8-

12 boats may be following a single whale (Rugh et al.,

1999).

The eastern North Pacific gray whale population is the only marine mammal stock occurring in

the project area that is subject to subsistence hunting. The current (1998-2002) International Whaling

Commission (IWC) quota allows for a harvest of 140

gray whales per year for local consumption (NMFS,

2001). In Russia between 1990-1998, aboriginal hunters averaged 139 whales per year along the Chukhotka

Peninsula; the Russian Federation has agreed to take

no more than 135 per year during 1998-2002 (NMFS,

2001).
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Delineation Drilling Activities Offshore Santa Barbara County

No take has been allowed in Alaska by the IWC

since 1991. However, there were 2 incidental takes by

an Alaskan Native in 1995 (Quan, 1999). The Makah

tribe of Washington received a 5-year quota to harvest

20 gray whales for ceremonial and subsistence purposes, with an allowed take of up to 5 per year during

1998-2002. One whale was struck and killed in May

1999 (NMFS, 2001).

Marine pollutants present a potential health

hazard for marine mammals (O’Shea, 1999). Marine

mammals include high-order marine predators that

may be affected by the bioaccumulation of contaminants (Reijnders, 1986). Most marine mammal species have large stores of fat, acting both as insulation

and as an energy reserve. Lipophilic contaminants

can accumulate in this tissue and may be released at

high concentrations when the energy reserves are mobilized (UNEP, 1991). No marine mammal deaths in

the wild have conclusively been shown to result directly from exposure to organochlorines or toxic elements (O’Shea, 1999). In a few highly polluted areas,

reproductive impairment and gross lesions in association with organochlorine contamination have been

demonstrated, although there have been few causeand-effect studies; the evidence for linkages with increased susceptibility to disease is mixed (O’Shea,

1999; O’Shea et al., 1999). Although the detrimental

impacts of organochlorine contaminants on marine

mammal populations have not been demonstrated with

scientific certainty, there is a growing body of circumstantial evidence that such effects are occurring

(O’Shea, 1999).

Few west-coast cetacean species have been tested

for the presence of contaminants. However, pollutant

levels, especially DDT residue levels, measured in California coastal bottlenose dolphins were found to be

among the highest of any cetacean examined (O’Shea

et al., 1980; Schafer et al., 1984; Forney et al., 2000).

Results from the analysis of samples taken from killer

whales in British Columbia coastal waters suggest that

killer whales in the northeastern Pacific Ocean are

highly contaminated with polychlorinated biphenyls

(PCBs) and that the marine mammal-eating transient

whales may be at particular risk for adverse effects

(Ross et al., 2000).

A gray whale contaminant study has been conducted by Tilbury et al. (1999). The authors theorized that gray whale fasting during migration could

alter the disposition of toxic chemicals within the

whale’s bodies. Thus, the whales may retain contaminants such as PCBs during fasting. Elevated levels of

certain trace elements (e.g., cadmium) and aluminum

in the tissues of stranded and harvested gray whales,

compared with other marine mammals, were felt to be

consistent with the ingestion of sediment during feeding.

A recent assessment of organochlorine levels in

eastern North Pacific gray whales indicates that reproductive females may transfer contaminants to their

calves, although the effects of observed contaminant

levels on fetal development and calf health have not

been determined (Krahn et al., 2000; NMFS, 2001).

Tissue samples from two gray whales in Washington

State revealed organochlorine (PCB and DDT) concentrations below U.S. Food and Drug Administration

regulatory tolerance limits for human consumption

based on fish and shell fish guidelines (Ylitalo et al.,

1999; NMFS, 2001).

Pinnipeds such as California sea lions and harbor seals are primarily coastal animals and are probably susceptible to the effects of coastal pollution.

Organic pollutants are known to cause reproductive

failure in harbor seals (Reijnders, 1986). In the early

1970’s, DeLong et al. (1973) suggested a possible causeeffect relationship between high levels of organic pollutants and premature births in California sea lions,

but this apparently involved only a small percentage

of annual pup production. Total DDT residues in California sea lions from southern and central California

were high in the early 1970’s (average levels up to 911

ppm wet weight) (Le Boeuf and Bonnell, 1971; DeLong

et al., 1973); by the early 1990’s, sampled levels were

substantially lower (average levels of 5-24 ppm wet

weight) (Lieberg-Clark et al., 1995). This trend, plus

the cessation of DDT production, suggests that organochlorine contaminant levels will continue to drop

(B.J. Le Boeuf, UC Santa Cruz, pers. comm.).

Non-anthropogenic Sources of Impacts. A number of diseases are known to occur in wild marine

mammal populations (Geraci and Lounsbury, 1993).

Except for leptospirosis in California sea lions

(Gilmartin et al., 1976; Dierauf et al., 1985) and northern fur seals (York, 1987), bacteria do not appear to

be significant agents of disease in marine mammals

(Geraci and Lounsbury, 1993). However, viruses have

emerged as serious pathogens in several species of cetaceans and pinnipeds (Geraci and Lounsbury, 1993).

Morbillivirus was implicated in the 1987-1988 mass

mortality of bottlenose dolphins on the U.S. Atlantic

coast (Lipscomb et al., 1994) and apparently killed

hundreds of striped dolphins (Stenella coeruleoalba)

in the Mediterranean in the early 1990’s (Duignan et

al., 1992). The California coastal population of bottlenose dolphins may be vulnerable to the effects of similar morbillivirus outbreaks (Forney et al., 2000).

One type of morbillivirus, phocine distemper virus, was first described in the late 1980’s, and outbreaks in western Europe were associated with the

death of thousands of harbor seals (Ham-Lammé et

al., 1999). Recent data on west-coast harbor seals reveal that morbillivirus is not endemic in the population, indicating that this population may be extremely

susceptible to an epizootic of the disease (Ham-Lammé
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Environmental Consequences, Cumulative Impacts (2002 - 2006), and Mitigation Measures

et al., 1999). A calcivirus, identified as the San Miguel

sea lion virus, is known to infect at least 11 species of

marine mammals, including sea lions, fur seals, elephant seals, gray and sperm whales, and bottlenose

dolphins (Smith et al., 1998).

A number of naturally occurring marine toxins

are known to have killed marine mammals (Geraci

and Lounsbury, 1993). Saxitoxin produced by the dinoflagellate Gonyaulax tamarensis (responsible for

paralytic shellfish poisoning in humans) killed at least

14 humpback whales off New England in the late

1980’s (Geraci et al., 1989). During the same period,

a brevetoxin produced by the dinoflagellate

Gymnodinium breve was implicated in mass bottlenose

dolphin mortality along the U.S. Atlantic coast

(Geraci, 1989). In 1998, an outbreak of domoic acid

toxicity resulting from a bloom of the diatom

Pseudonitzchia australis affected tens of California sea

lions along the California coast (Gulland, 2000).

For reasons that are not yet understood, gray

whales have been stranding with increasing frequency

during the last two or three years. Norman et al.

(2000) reported that 273 gray whales stranded in 1999

along the west coast of North America from Alaska to

Mexico, a number that is 5-13 times higher than annual stranding counts from 1995 to 1998 (IWC, 2000;

NMFS, 2001). An additional 291 gray whale

strandings were recorded in the U.S. and Mexico during the first five months of 2000 (NMFS, 2001). Although the IWC Scientific Committee concluded that

the increase in per capita mortality rate indicated by

these strandings, plus observed decreases in calf production in 1999 and 2000, could have caused an overall decrease in the abundance of the eastern North

Pacific gray whale population, the current status of

the stock cannot be assessed without new survey data

(NMFS, 2001).

Four strong El Niño events in the past 30 years

have adversely affected the annual production, pup

mortality, and pup growth of California pinniped populations, particularly on the Channel Islands (DeLong

and Melin, 2000). The species affected include the

California sea lion, northern fur seal, and, to a lesser

extent, northern elephant seal. Such strong El Niño

events can reduce population levels for several years.

Incremental Impacts Associated of the Proposed Action (2002-2006): As discussed in section

5.2.8.1, activities associated with the proposed delineation activities are expected to result in temporary

(less than 1-hour), localized disturbances to some

marine mammals in the project area. These impacts

are considered to be negligible to low. No impacts are

expected from effluent discharges.

SUMMARY AND CONCLUSIONS (2002-2006):

Currently, the primary source of human-related

impacts to marine mammals in the project area is incidental take in commercial fishing operations. However, these impacts are likely to decrease as additional

restrictions and mitigation measures are imposed on

coastal fisheries. For non-threatened and endangered

species, the incidental take of harbor porpoises is of

greatest concern at present.

Gray whales are also subject to a subsistence

harvest in the Russian Arctic, although this source of

mortality is not believed to have a significant effect on

the population. However, the recent increase in gray

whale strandings has raised concerns that an overall

population decline may be occurring.

Although the effects of noise and disturbance

generated by the Proposed Action are not expected to

be significant in themselves, they will add to the cumulative noise and disturbance levels that marine

mammals are subject to in the Santa Barbara Channel and Santa Maria Basin. In general, the presence

of multiple sources of noise and disturbance, such as

stationary OCS activities (construction, drilling, and

production), ship and boat noise, aircraft, and seismic exploration noise, should result in more frequent

masking of communications, behavioral disruption,

and short-term displacement. In other areas, there is

also some evidence for long-term displacement of marine mammals due to disturbance, particularly in relatively confined bodies of water (summarized in

Richardson et al., 1995). Although some OCS activities off southern California, such as construction and

seismic surveys, have declined over the past decade,

overall vessel traffic, including commercial, military,

and private vessels, is increasing.

These effects may be somewhat mitigated by habituation. Indeed, marine mammal populations in

California waters have generally been growing in recent decades (Bonnell and Dailey, 1993; Barlow et al.,

1997; Forney et al., 2000), despite a gradual increase

in a wide variety of human activities in the area. There

is no evidence that the noise and disturbance created

by offshore oil and gas activities in both Federal and

State waters and by increasing vessel traffic (of which

oil and gas support vessels are a small part) have resulted in adverse impacts on marine mammal populations. By the impact level criteria adopted for this

document (section 5.2), these impacts are considered

to be low. The very minor effects in space and time

projected to occur as a result of the proposed delineation activities are not expected to add measurably to

cumulative impacts to marine mammals in the area.

No oil spills are expected to result from the Proposed Action. However, accidental oil spills do present

an ongoing source of potential impacts to marine mammals. The cumulative risk of oil spills arises from

multiple sources, including offshore oil and gas ac-
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Delineation Drilling Activities Offshore Santa Barbara County

tivities in Federal and State waters and both Alaskan

and foreign-import tankering. The greatest oil spill

risk to marine mammals in the project area results

from tankering operations. This risk is tempered by

recently implemented or proposed mitigation (such as

the rerouting of tankers farther offshore along the

central California coast) and, as discussed in section

5.1.3, by modern oil spill response capabilities.

If an oil spill were to occur in the project area

during the period 2002-2006, impacts to marine mammals could range from negligible to high, depending

on spill size, location, season, and a number of other

factors. Most at risk are pinniped pups. Seasonally,

the most sensitive areas are rookeries on the northern Channel Islands (particularly San Miguel Island)

and along the mainland coast north of Point Conception.

The probabilities that one or more oil spills will

occur during the period 2002-2006 from existing and

proposed offshore oil and gas activities are 94.9 percent for a spill of 200 bbl or less and 41.2 percent for a

spill of 2,000 bbl. The probability of a 22,800-bbl tanker

spill occurring during this period is 38.8 percent.

5.2.9 IMPACTS OF THE PROPOSED

ACTION AND CUMULATIVE IMPACT

ANALYSIS FOR THREATENED AND

ENDANGERED SPECIES

This section analyzes the impacts of the Proposed Action on threatened and endangered species in

the project area. Threatened and endangered species

may be vulnerable to several potentially adverse impacts from operations associated with the Proposed

Action. Operations assumed to occur as a result of

this project include towing and anchoring the MODU,

support vessel traffic, helicopter flights, drilling, various discharges, barge transit and anchoring, and well

abandonment. These operations are described in section 2. As discussed in section 5.1.1, no oil spills are

expected to occur from the proposed drilling activities

associated with this project; therefore, no impacts to

threatened and endangered species from oil spills are

expected.

Impact level definitions used in this analysis are

as follows:

HIGH

Impacts result in a population decline in the

project area due to direct mortality, reduced survivorship, declines in reproduction, and/or a shift in distribution. The decline, which could involve more than 5

percent of the total population, would be at a level

and over a large enough area that the continued existence or recovery of the species involved would be at

risk.

MODERATE

Impacts result in a local (e.g., single colony)

population decline due to direct mortality, reduced

survivorship, declines in reproduction, and/or a shift

in distribution. The decline, which could involve from

1 to 5 percent of the total population, could increase

the length of time projected for full recovery and removal from the endangered species list, depending on

the species involved. Effects are expected to continue

for 1-5 years.

LOW

Impacts result mainly in local (e.g., a small area

around a platform, a limited stretch of beach or, rocky

shore), short-term (a few days to a few weeks) changes

in behavior (e.g., disruption of foraging) and/or displacement from roosting or foraging habitats due to

disturbance. Mortality, if any, would be limited to the

loss of a few animals up to 1 percent of the total population of the species or stock. A small number of animals would also suffer from sublethal effects. Effects

are expected to continue for less than 1 year. Projected recovery time and removal from the endangered

species list would not be affected.

Impacts below these levels, involving no death

or life-threatening injury of any threatened or endangered organism, no displacement from preferred habitat, and no more than minor disruption of behavioral

patterns, are defined as negligible. For purposes of

this document, high and moderate impacts are considered to be significant; low impacts are considered to

be insignificant.

5.2.9.1 IMPACTS OF THE PROPOSED

ACTION ON THREATENED AND

ENDANGERED MARINE MAMMALS

Section 5.2.8.1 describes the potential impacts

of the Proposed Action on marine mammals in the

project area. The primary impact-producing activities associated with the Proposed Action include delineation drilling operations with associated support

activities and are common to all the units. The major

impact agents expected from these proposed activities

are noise and disturbance and drilling discharges. The

potential use of explosives in the abandonment of the

delineation wells also raises the possibility of lethal

impacts to marine mammals.

Blue Whale. Marine mammal responses to noise

and disturbance are discussed in section 5.2.8.1. The

minor and temporary increases in sound levels produced during the delineation drilling activities are

unlikely to affect blue whale movements through the