purcc 2012 - University of the Pacific

Poster Session Abstracts
1.8MHz). DIDSON is particularly useful in
murky or rough waters because targets within the
field-of-view are imaged through sound waves
rather than traditional video imagery. Although
studies have been conducted as to the accuracy
and precision of estimating length with the
DIDSON, none in which range and frequency
were analyzed simultaneously have been
conducted. Our artificial target was manually
operated in a controlled pool environment and
lengths were measured by the Fish-Marking tool
in the DIDSON software. We had four test
groups: low frequency at 5 m, high frequency at
5 m, low frequency at 10 m and high frequency
at 10 m. The statistical analysis revealed that
target range had a significant effect on DIDSON
derived measurements while frequency did not.
DIDSON-derived length measurements were
significantly smaller than the actual target length
at both ranges tested.
Growth Rate Differences Amongst
Leiostomus xanthurus Between Varying
Estuarine Creeks
Diana Furukawa, Breanna Wong
Faculty Mentor: Dr. Stacy Luthy
An estuary is a semi-enclosed coastal area where
freshwater and saltwater blend. In the past,
research has shown that certain areas within
estuaries, such as wetlands and seagrass
meadows, have been identified as fish nurseries.
An area is considered to be a nursery if it
contributes “higher density, survival, growth,
and movement to adult habitat”. The purpose of
this study was to test whether there were
differences in nursery habitat quality between
closely related intertidal creeks within North
Inlet Estuary, SC. Samples of juvenile spot
Leiostomus xanthurus were collected from
Oyster Landing, Bly Creek, and Old Man, three
different creeks within the region that are
geographically close in range. Each specimen
was dissected in order to isolate the otoliths,
specifically the right and left lapilli and sagittae.
Otoliths are calcareous, vestibular structures
found within the inner ear of bony fish. As the
fish grows, rings develop on the otolith, which
can be counted to estimate age. In this study,
only the left lapillus was subjected to further
evaluation. Lengths were measured and ages
were estimated via otolith analysis. Growth rates
were used as an indicator of nursery quality, with
the assumption that a better habitat would
support faster growth. Results showed that ages
of fish from different creeks were similar;
however, their lengths were significantly
different. This proves that the growth rates of
fish vary between creeks, indicating fine-scale
differences in nursery habitat quality within the
estuary.
Comparing Sand Flipping of Elephant
Seals between Sex and Age
Hasan Alkazemi, Jonathan Choy, Lan Tran
Faculty Mentor: Richard Tenaza
Abstract Text: Every winter northern elephant
seals (Mirounga angustirostris) come ashore at
several coastal and island sites on sandy shores
of central and southern California and western
Mexico to breed, give birth, and rear their pups
to weaning. The adult male’s nose is a
protruding proboscis, resembling the trunk of an
elephant. While ashore, elephant seals
frequently scoop sand with a backward motion
of the front flippers and throw it onto
themselves, an action known as sand flipping.
We investigated age and sex differences among
elephant seals in their frequencies performing
this behavior at a breeding colony at Piedras
Blancas California. The research builds upon
previous studies conducted by other Pacific
students during in 2010 and 2011 breeding
seasons at Piedras Blancas.
Comparison of Aggression between
Female Elephant Seals with Pups and
without Pups towards Non-Filial Pups
Sejal Bhayani, Antonia Centeno, Quang
Nguyen
Faculty Mentor: Richard Tenaza
Our research tests the hypothesis that adult
female elephant seals with pups are more
aggressive toward strange (non-filial) pups than
are females without pups. Working from video
recordings of portions of the elephant seal
colony, we will observe and tabulate behavior of
equal numbers of both types of females toward
non-filial pups, analyzing interactions one
female at a time. This research was conducted in
2012 in two separate weekends at San Simian on
January 21st and 22nd, and February 4th and 5th.
It was observed that females were aggressive to
non-filial pups through the behaviors of biting,
chasing, and vocalizations. Our hypothesis
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