Since the passage
of the Marine Mammal Protection Act (MMPA)
in 1972, populations of Pacific harbor seals and California sea
lions have increased dramatically, and are now considered healthy
and robust. The increased abundance has been accompanied by
growing number of interactions with humans, raising concerns by
private citizens and government officials who are seeking ways to
protect property, fishing gear, and catch from damage by sea lions
The MMPA generally
capturing, or killing of marine mammals, or any attempt to engage in
such activities. However, the law does contain exceptions
authorizing certain people under certain circumstances to deter
marine mammals from damaging private property, including fishing
gear and catch, so long as the methods used do not result in the
death or serious injury of an animal. To reduce the risk of
causing "serious injury" to an animal, deterrence methods should be
chosen that avoid the penetration or tearing of skin, or rupture of
NMFS is developing
formal guidelines and regulations for safely and legally deterring
marine mammals. That guidance is not yet available, so in the
interim, NMFS is providing this advice for deterring Pacific harbor
seals and California sea lions (see potential deterrence
methods at the end of these Questions and Answers).
There is no single
non-lethal deterrence method known to be universally effective in
discouraging Pacific harbor seals and California sea lions from engaging in problem behaviors.
Nevertheless, the following list of methods and techniques have been
found useful, in some circumstances, for deterring problem animals
that are damaging property, fishing gear, or catch. The
following lists are methods property owners and fishers may consider
for use under the appropriate conditions.
of the methods listed below (e.g., loud noise or
pyrotechnics) may not be appropriate for use in some
areas or subject to prohibition under state or local
ordinances. Additionally, the presence of ESA-listed
species in some areas may advise against the use of
certain methods. Please consult with local
authorities to determine if such prohibitions exist in
your area, or if listed species may be encountered.
Only marine mammals
that are not listed under the Endangered Species Act (ESA)
may be deterred to protect private property, including gear and
catch (read more).
ESA-listed and non-listed species of sea lions and seals that occur
in coastal and inland waterways of California, Oregon, and
(may NOT be
deterred by public)
deterred by public)
Steller Sea Lion
links for species’ descriptions, ranges, and photos)
for a description of sea lion and seal “trouble spots” )
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The MMPA does not
allow private citizens to deter marine mammals from un-developed
property (e.g., a beach) or public property (e.g., a breakwater).
Private citizens may only deter Pacific harbor seals and California
sea lions that
are exhibiting problem behavior that is resulting in, or could
result in, damage to private property, fishing gear, or catch.
Do the MMPA and
ESA grant additional authority to government officials?
Yes. The MMPA
and ESA provide authority to city, county, state, and federal
government officials or their employees to deter “nuisance” marine
mammals to prevent damage to public property or to protect
the public from potential threats by a nuisance animal
Pacific harbor seals and California sea lions may not result in the following:
Serious Injury or Mortality
– The MMPA authorizes deterrence using
non-lethal methods only. Deterrence cannot result in the
death or serious injury of marine mammals. NMFS has
defined "serious injury" in regulations to include an injury
that is likely to lead to the death of the affected marine
mammal (read more).
Deterrence of ESA-Listed
As noted above, the intended or unintended deterrence of
threatened or endangered marine mammals is not allowed.
Violation of State Laws or
Local Ordinances –
The use of some deterrence methods may be
prohibited or restricted by states or local governments.
For example, a city or county may prohibit the use of, or
require special permits for, pyrotechnics. It is your
responsibility to check with your local authorities to ensure
that any deterrence methods used comply with local and state
Risk to Human Safety
– If you deter a seal or sea lion in such
a manner that you cause injury to another person, you may be
liable for your actions.
Taking of Non-Target Marine
Deterrence is not authorized if it will result in the death,
serious injury, or harassment of non-target marine mammals
(i.e., individuals other than those causing damage to private
property, gear or catch (read
Who may deter
Pacific harbor seals and California sea
certain private citizens, marina owners, government officials, and
commercial and recreational fisherman may deter Pacific harbor seals
and California sea lions
under certain conditions, as described below:
– Only the owner of the private property
(e.g., a dock or vessel) may deter
Pacific harbor seals and California sea lions in order to prevent damage to their private property.
– Only the marina owner, or an employee of
the owner, or an agent of the owner may deter
Pacific harbor seals and California sea lions to prevent damage to the marina.
– City, county, state, or federal
officials or their employees may deter listed and
Pacific harbor seals and California sea lions determined to be “nuisance” animals to prevent
damage to private or public property, or to protect the public
from potential threats (read more).
Commercial and Recreational
Fishermen can deter
Pacific harbor seals
and California sea lions from damaging
gear or depredating catch, only if they are actively fishing.