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Harbor Seal Dilemma
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CMBC students comment on controversial local issue |
Sealing their fate: The harbor seal dilemma at
Children's Pool beach in La Jolla, California
Matt Forrest, Ryan Wulff, Steve Chapple, and Hiro Yokoyama
A colony of over 100 harbor seals (Phoca vitulina richardsi)
has occupied the beach of the Children's Pool in La Jolla for the past
two decades. This colony has become a popular tourist attraction and is
regarded as an educational opportunity for local schools. Although
marine mammals are protected by law, some people object to the recent
intrusion of the seals into Children's Pool, which was formed in 1931
when a seawall was built around a natural cove to protect bathers,
primarily children learning to swim, from the crashing waves.
Proponents for removing the seals argue their presence heightens risks
to human bathers through the possibility of attack and exposure to
fecal-contaminated water. The seals have been receiving varying degrees
of protection over  the
years, primarily by volunteer docents. Recently, a local swimmer filed
a lawsuit demanding that the City return the pool to its original
state. In August 2005, a Superior Court judge ruled that the City of
San Diego must dredge sand from the beach within six months. It is
presumed that dredging would have the effect of lessening the level of
fecal contamination, attributed to the seals, in the pool water and
thus re-opening the beach for use by humans. Advocates of the dredging
also believe that it may reduce the number of seals using the beach.
This decision has been appealed by the City, and as of this writing, it
is unclear whether the dredging will take place.
In 1999, the
City of San Diego rejected a similar dredging proposal as an effective
way to deal with the seal dilemma. It deemed dredging as pointless
because the evidence suggested that it would not rid the beach of the
seals, nor lower the fecal contamination problems in the Children's
Pool. Although the 2005 court decision now mandates dredging, we agree
with the City's 1999 opinion that it is unlikely to succeed. We feel
that dredging is ill advised for several reasons. First, the seawall is
a barrier to longshore beach sand transport and, over the years, sand
carried from the adjacent beaches was deposited behind the seawall
where it formed a steep, wide beach. According to Dr. Douglas Inman, a
coastal erosion expert at the Scripps Institution of Oceanography, the
sand on the Children's Pool Beach is now an integral part of the sand
budget for the for the Boomer Beach-Children's Pool area; if it is
removed by dredging, it will ultimately be replaced by sand scoured
from nearby beaches, such as Boomer Beach and Shell Beach. Because
beach sand diminishes the effects of wave action, beaches experiencing
additional sand removal will have a greater potential for local cliff
erosion. It is also likely that these other beaches will be partially,
or completely, denuded of their sand, which may result in the loss of
two popular beach destinations. Second, it is unlikely that dredging
will improve the fecal contamination problem, because it is
questionable whether it will enhance water circulation. In fact, a
report by the engineers hired by the City to perform the dredging
concluded that this action could actually worsen the fecal
contamination problem if the seals remain. Third, because biological
studies show that harbor seals have a high fidelity to the sites where
they congregate, and particularly where they were born, it seems
unlikely that dredging would reduce the number of seals occupying
Children's Pool Beach. It is also worth noting that the presence of
sand is not a prerequisite for hauling out, and that many harbor seal
rookeries occur on rocks.
The situation with the seals at the
Children's Pool Beach has evoked strong and contentious feelings and
actions. While those for and against the seal presence both make
legitimate arguments, emotion has played a larger role than science in
determining the possible actions that should be taken. It is debatable
whether it was a good idea to let the harbor seals establish a rookery
at the Children's Pool Beach. 
However, the fact remains that the seals that were born there will
almost certainly return, and that dredging the area and removing sand
is not likely to affect their numbers nor alleviate the water quality
issues. Our opinion is that the most sensible course of action is to
abandon the dredging proposal, and to institute a seasonal joint use
plan for the area. A removable rope barrier would be erected to protect
the seals during the pupping season (January - June), and people would
be allowed to swim and recreate there the rest of the year at their own
risk. We also suggest that a full time ranger should be stationed at
the Children's Pool Beach in order to provide educational information
and to alleviate the many negative interactions that occur--between
people and seals, but primarily between the diametrically opposed
factions of seal supporters and detractors. Although this may appear to
be a rather expensive proposition, the estimated cost of the entire
dredging proposal is $500,000, and part of this money was actually set
aside to hire a ranger. Because all available evidence suggests that
the dredging will not result in improving the situation, we feel that a
seasonal joint use plan overseen by a trained ranger offers the best
possible solution to the harbor seal dilemma, and the best prospects
for future harmony at the Children's Pool Beach.
***This report reflects the opinions of the CMBC students and not necessarily those of CMBC.***
The students:
Matt Forrest is a CMBC IGERT Associate
Ryan Wulff, Steve Chapple, and Hiro Yokoyama are students in CMBC's MAS program.
For updates on the issue and other opinions:
Lecky, James H. Report from Marine Mammal Workshop. Whose Beach is it Anyway?
download pdf
San Diego Coastkeeper
Sign on San Diego
La Jolla Friends of the Seal
For more information on coastal erosion:
Coastal Bluffs Provide More Sand to California Beaches than Previously Believed
Photo credit: (Child) Kenneth & Gabrielle Adelman - adelman@adelman.com
Photo credit: (Tourists) Roni Galgano/Union Tribune
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