ArticlePDF Available

Tracking and mapping sun-synchronous migrations and diel space use patterns of Haemulon sciurus and Lutjanus apodus in the U.S. Virgin Islands

Authors:

Abstract and Figures

The spatially explicit diel movement patterns of fish using coral reef ecosystems are not well understood, despite the widespread recognition that many common species undergo distinct migrations to utilize different resources during night and day. We used manual acoustic telemetry coupled with global positioning technology to track the detailed spatially explicit daily movements (24 h) of multiple individuals of two common Caribbean fish species, Haemulon sciurus (bluestriped grunt) and Lutjanus apodus (schoolmaster snapper). Movement pathways and day and night activity spaces were mapped and quantified in a Geographic Information System (GIS). Directional sun-synchronous migrations occurred close to astronomical sunset and sunrise. Site fidelity within day and night activity spaces was high. Nine of twelve individuals exhibited overlap of day and night activity spaces and three fish (L. apodus) exhibited complete spatial segregation. Night activity spaces (H. sciurus: 11,309 ± 3,548 m2; L. apodus: 9,950 ± 3,120 m2) were significantly larger than day activity spaces (H. sciurus: 2,778 ± 1,979 m2; L. apodus: 1,291 ± 636 m2). The distance between sequential position fixes (step lengths) was significantly greater at night than day, indicative of nocturnal foraging and day resting behavior. Integrating acoustic telemetry, GIS techniques and spatial statistics to study fish movement behavior revealed both individual variability and some broader generality in movement paths and activity spaces suggestive of complex underlying behavioral mechanisms influencing diel movements.
Content may be subject to copyright.
1 23
Environmental Biology of Fishes
ISSN 0378-1909
Volume 92
Number 4
Environ Biol Fish (2011) 92:525-538
DOI 10.1007/s10641-011-9875-2
Tracking and mapping sun-synchronous
migrations and diel space use patterns of
Haemulon sciurus and Lutjanus apodus in
the U.S. Virgin Islands
Steven Hitt, Simon J.Pittman & Kerry
A.Brown
1 23
Your article is protected by copyright and
all rights are held exclusively by Springer
Science+Business Media B.V.. This e-offprint
is for personal use only and shall not be self-
archived in electronic repositories. If you
wish to self-archive your work, please use the
accepted author’s version for posting to your
own website or your institution’s repository.
You may further deposit the accepted author’s
version on a funder’s repository at a funder’s
request, provided it is not made publicly
available until 12 months after publication.
Tracking and mapping sun-synchronous migrations and diel
space use patterns of Haemulon sciurus and Lutjanus apodus
in the U.S. Virgin Islands
Steven Hitt & Simon J. Pittman & Kerry A. Brown
Received: 20 September 2010 / Accepted: 23 June 2011 /Published online: 16 July 2011
#
Springer Science+Business Media B.V. 2011
Abstract The spatially explicit diel movement patterns
of fish using coral reef ecosystems are not well
understood, despite the widespread recognition that
many common species undergo distinct migrations to
utilize different resources during night and day. We used
manual acoustic telemetry coupled with global posi-
tioning technology to track the detailed spatially explicit
daily movements (24 h) of multiple individuals of two
common Caribbean fish species, Haemulon sciurus
(bluestriped grunt) and Lutjanus apodus (schoolmaster
snapper). Movement pathways and day and night
activity spaces were mapped and quantified in a
Geographic Information System (GIS). Directional
sun-synchronous migrations occurred close to astro-
nomical sunset and sunrise. Site fidelity within day and
night activity spaces was high. Nine of twelve
individuals exhibited overlap of day and night activity
spaces and three fish (L. apodus) exhibited complete
spatial segregation. Night activity spaces (H. sciurus:
11,309± 3,548 m
2
; L. apodus: 9,950±3,120 m
2
)were
significantly larger than day activity spaces (H. sciurus:
2,778±1,979 m
2
; L. apodus:1,291±636m
2
). The
distance between sequentia l position fixes (step
lengths) was significantly greater at night than day,
indicative of noctur nal f oragin g and d ay resti ng
behavior. Integrating acoustic telemetry, GIS techni-
ques and spatial statistics to study fish movement
behavior revealed both individual variability and some
broader generality in movement paths and activity
spaces suggestive of complex underlying behavioral
mechanisms influencing diel movements.
Keywords Acoustic telemetry
.
Fish
.
Movement
.
Space use
.
Diel migrations
.
Caribbean
Introduction
Movement behavior is a key ecological process in
animal ecology that determines the way individuals
utilize their environment in time and space and is
interlinked with growth, survival, predatorprey inter-
actions and population distribution and abundance
(Turchin 1998; Pittman and McAlpine 2003;Nathan
et al. 2008). Diel migration behavior is a widespread
strategy for marine organisms associated with coral
reef ecosystems where optimal combinations of key
Environ Biol Fish (2011) 92:525538
DOI 10.1007/s10641-011-9875-2
S. Hitt
:
S. J. Pittman (*)
Center for Marine and Environmental Studies,
University of the Virgin Islands,
2 John Brewers Bay,
St. Thomas, Virgin Islands 00802, USA
e-mail: simon.pittman@noaa.gov
S. J. Pittman
NOAA/NOS/NCCOS/CCMA,
Biogeography Branch, 1305 Eastwest Highway,
Silver Spring, MD 20910, USA
K. A. Brown
School of Geography, Geology, and the Environment,
Kingston University London,
Kingston-Upon-Thames KT1 1LQ, UK
Author's personal copy
resources are distributed over a mosaic of patch types
(Krumme 2009). A diel migration involves two-way
movements between spatially separated day and night
activity spaces often scheduled to coincide with
changes in solar light intensity (i.e., sun-synchronous)
(McFarland et al. 1979;Krumme2009). This strategy
is thought to allow fish to selectively utilize spatially
segregated resources within different portions of their
home range and may also help maximize growth while
minimizing predation risk and ultimately enhancing
survival (Hobson 1973; Dahlgren and Eggleston 2000;
Halpin 2000). From an ecosystem dynamics perspec-
tive, migrating fish connect different patch types across
the seascape and facilitate nutrient and energy flow
through trophic relationships, diel shifts in food web
dynamics and expulsion of waste products that
influence ecological processes (Meyer et al. 1983;
Meyer and Schultz 1985; Clark et al. 2009).
Several common fish species associated with
Caribbean coral reef ecosystems have been observed
to undertake twilight migrations to move to and from
day and night portions of their daily home range
(Ogden and Buckman 1973; Dubin and Baker 1982;
Rooker and Dennis 1991; Nagelkerken et al. 2000).
The phenomenon has most often been documented for
haemulids (e.g. Ogden and Ehrlich 1977; McFarland et
al. 1979; Helfman et al. 1982; Rooker and Dennis
1991; Tulevech and Recksiek 1994; Nagelkerken et al.
2000), lutjanids (e.g. Nagelkerken et al. 2000; Verweij
et al. 2007) and parrotfish (Ogden and Buckman 1973;
Dubin and Baker 1982).
Nocturnal migrations that follow consistent migra-
tory pathways have been linked to effective partition-
ing of foraging grounds in these species (Ogden and
Zieman 1977). H. sciurus and L. apodus are nocturnal
carnivores that a re thought to move at night from
structurally complex diurnal shelters (Verweij and
Nagelkerken 2007; Verweij et al. 2007) to feed on
macro-benthic invertebrates that occur in elevated
abundances in seagrass and macroalgal bed sediments
(Rooker and Dennis 1991;Burke1995; Nagelkerken et
al. 2000; Beets et al. 2003; Cocheret de la Morinière et
al. 2003a, b; Nagelkerken and van der Velde 2004a, b;
Verweijetal.2007). However, L. apodus transitions
primarily to a piscine diet following ontogenetic
shifts to coral reefs (Cocheret de la Morinière et al.
2003a, b). The necessity for H. sciurus and L. apodus to
partition soft-sediment foraging habitats, such as sand,
seagra ss and macroalgal beds may, therefore, be
augmented by the high degree of dietary overlap that
exists between these and other grunt and snapper
species (SchoenersIndex=3370%; Cocheret de la
Morinière et al. 2003b). Moreover, nocturnal migration
behaviors allow fish to forage away from high predation
risk ecotones that exist between adjacent habitats such
as mangroves and seagrass beds (Hammerschlag et al.
2010a, b). Therefore, nocturnal migrations and the
preferential use of seagrass beds at night appear to
be functionally and ecologically advantageous for-
aging strat egies that simultaneously capitalize o n
higher prey densit ies, mitigate predation risk and
intra- and inter-specific competition, a nd maximize
foraging efficiency (Dahlgren and Eggles ton 2000;
Hammerschlag et al. 2010a).
Much of the knowledge of fish movement behavior
has been generated from underwater observational
studies using visual census techniques (i.e., belt trans-
ects, roving diver counts, tag re-sightings, etc.), which
have provided great insight into many key behavioral
patterns. These studies, however, are usually carried out
in daylight or twilight hours and thus offer limited
information on the movements of fish over the full
spatial extent of their daily home range. Furthermore,
observational studies rarely provide data suitable for
reconstruction and quantitative, spatially explicit analy-
ses of detailed movement pathways and space use
patterns throughout the home range. The lack of data on
space use, especially, areal estimates of activity spaces
and their physical arrangement in space and time
severely limits our capacity to conduct comparative
studies among species.
Manual acoustic telemetry coupled to a global
positioning system (GPS) provides real-time spatial
movement data in a cost-effective way (i.e., compared
to autonomous acoustic receiver arrays) with minimal
bias on the behavior of the target organism. At night,
acoustic tracking allows the researcher to locate individ-
ual animals that would be very difficult to visually
observe. Spatially referenced tracking data can then be
used to reconstruct detailed movement pathways and
quantify both the physical complexity of pathways
(Papastamatiou et al. 2009), the spatial characteristics
of activity spaces (Lowe et al. 2003; Childs et al. 2008)
and to link movement pathways to seascape structure
using remote sensing and a suite of Geographical
Information System (GIS) tools (Hitt et al. 201 1).
Recent advances in marine acoustic telemetry and
spatial technologies (i.e., GPS and GIS) to reliably
526 Environ Biol Fish (2011) 92:525538
Author's personal copy
record geographical positions and to analyze space use
patterns at a range of spatial and temporal scales have
advanced the study of movement ecology for marine
species. Movement paths are typically analyzed as a
series of consecutive positional fixes connected by finite
segments (usually straight lines) (Getz and Saltz 2008).
These segments are referred to as step lengths and can
be analyzed to quantify variables such as total distance
traveled, movement speed, turning angles, path com-
plexity or tortuosity, and site fidelity measures which
provide characterizations of organismal movement
capabilities, search patterns, and habitat preferences
(T urchin 1998). Linearity, which serves as a measure of
site fidelity (e.g. Morrissey and Gruber 1993) provides
information about the preferential utilization of certain
habitat types (or individual patches within habitats) by
an organism through time, since it is an indication of
how an organism correlates the progression of move-
ment (Bell and Kramer 1979). In other words, long,
straight movement paths will have start and endpoints
farther away from one another than highly convoluted
or circular paths (Fig. 1); the former indicates departure/
repulsion from a habitat whereas the latter indicates
relative site attachment. For marine management,
mapping space use patterns provides information on
ecologically meaningful spatial scales for key species
and this can be used to delineate essential fish habitat; to
examine the suitability of size, shape and seascape
inclusion within marine protected areas (MPAs); and the
optimal spacing within networks of MPAs (Pittman and
McAlpine 2003;Saleetal.2005; Monaco et al. 2007).
The importance of fish movement for MPA efficacy has
been noted by several authors. Kramer and Chapman
(1999) hypothesized that species with low mobility will
benefit most from marin e reserve protection, with more
highly mobile species benefiting less.
In order to identify and quantitatively characterize diel
migrations and day and night space use patterns in two
common Caribbean fish, Haemulon sciurus and Lutja-
nus apodus, we tagged and tracked twelve fish over
24 h using manual acoustic telemetry. We then mapped
and quantified space use patterns and movement path-
ways using a suite of spatial tools within a GIS. Several
tracking studies have calculated home range areas as a
minimum convex polygon (MCP) (McKibben and
Nelson 1986; Morrissey and Gruber 1993; Meyer et
al. 2000;Ortegaetal.2009). Instead, we examine
temporal components of movement activity within the
daily home range. As such, we have adopted the term
activity space to represent day and night (and twilight)
portions of the 24 h daily home range. Our overall aim
was to identify and characterize diel migrations and to
map and quantify inter- and intra- species space use
patterns for multiple individuals of H. sciurus and L.
apodus in two embayments on two different islands
within the U.S. Virgin Islands. We employed a
quantitative approach to test three hypotheses:
H
1
: Step length in the movement pathway wi ll
increase signi ficantly after sunset and preceding
Fig. 1 Conceptual
representations of the
measures used to describe
site fidelity, spatial
segregation of activity
spaces and migration,
respectively: a) Linearity
Index, b) Overlap Index
(OI) and c) centroid to
centroid distance
Environ Biol Fish (2011) 92:525538 527
Author's personal copy
sunrise indicating a highly directional sun-
synchronous diel migration.
H
2
: Day and night activity spaces are spatially
discrete areas (i.e. zero overlap) and;
H
3
(a): Site fidelity is significantly higher during
the day than at night (i.e., high site attachment),
but (H
3
b) step length is lower during the day-
indic ative of diurnal resting versus nocturnal
foraging behavior.
Materials and methods
Study sites
The study was conducted within two bays in the
United States Virgin Islands (Lameshur Bay, St.
John and Brewer s Bay, St. Thomas) between July
2008 and March 2 010 (Fig. 2). The bays are both
located on the southern coasts and each have similar
seascape features, including, large granite promon-
tories and rocky headlands, extensive Syringodium
filliforme and Thalassia testudinum seagrass beds,
Montastraea annularis dominated fringing coral
reefs, and colonized bedrock and boulder areas.
Lameshur Bay is located within the Virgin Islands
National Park (VINP). VINP is not a no-take area
and small-scale artisanal fishing occurs in both
bays.
Tagging and tracking
Between July 2008 and April 2010 baited fish traps
were used to acquire adult (> 24 cm tota l length, TL)
Haemulon sciurus ( n=6) and Lutjanus apodus (n=6)
individuals. Baited traps were set on soft bottom
habitats (i.e. sand, seagrass, etc.) within 5 m of coral
reef and were allowed to soak for 48 h (Fig. 2). Both
species were obtained during daylight hours (10:00
17:00), often at the same trap site or even within the
same trap and were transported in aerated containers
Fig. 2 Brewers Bay (left) and Lameshur Bay (right) contin-
uous fish tracking locations in the U.S. Virgin Islands and their
dominant benthic habitat types. Stars indicate areas where fish
were trapped. On St. John, Lameshur Bay is located within the
Virgin Islands National Park (VINP) and adjacent to the Virgin
Islands Coral Reef National Monument (VICRNM)
528 Environ Biol Fish (2011) 92:525538
Author's personal copy
between capture sites and the field station. Each fish was
measured (total length, TL) and a V9-2 L acoustic
transmitter with a one second ping interval (dimensions
9×29 mm, carrier frequencies 7584 kHz; Vemco,
Halifax, Nova Scotia, Canada) was surgically implanted
into their abdominal cavity ~1 cm anterior to the anus.
To aid recovery, post-operative fish were kept for
approximately 1 h under observation in a flow-through
seawater holding tank. Fish were then released at the
capture site by a snorkeler to ward off predators during
the descent to the substratum and observed for a few
minutes in-situ. Tracking of each fish commenced at
least 24 h after tag implantation to allow the fish to
recover sufficiently and resume normal home range
movement behavior.
Diel movements were quantified using established
continuous tracking techniques (Lowe et al. 2003;
Topping et al. 2005). A minimum of two researchers
were required; one manually operated a directional
hydrophone (Vemco model VH110) and acoustic
receiver (Vemco model VR100) at the bow of the
vessel, while the other operated the vessel (5.2 m
motorized catamara n) and recorded waypoints at 15 min
intervals using a handheld global positioning system
(GPS). GPS waypoints were only taken when the
transmitter signal strength was greater than 85% directly
below the vessel. During tracking events a single fish
was tracked for a total of 24 h by operator pairs working
in three 8 h shifts to gather movement pathway
locations totaling approximately 288 h of boat time for
the study. Fish were t racked in water 18 m depth with
no observable be havioral effects due to boat presence.
Mapping and quantifying movement behavior
and activity spaces
Sun-synchronous migrations
United States Naval Observatory sunrise/sunset time
charts
1
for Charlotte Amalie (St. Thomas) and Coral
Bay (St. John), USVI, were used to define day, night,
dawn and dusk periods. Sunset was defined as the hour
following the calculated sunset time and sunrise was
defined as the hour preceding the calculated sunrise
time. We defined day as the period of time between
dawn and dusk and night as the period between dusk
and dawn. To identify and quantitatively characterize
Haemulon sciurus and Lutjanus apodus diel migration
behavior, we calculated the distance between succes-
sive GPS fixes (i.e. step length) for the four periods of
the day using Hawths Analysis Tools for ArcGIS
v3.27 (Beyer 2004). We expected the distance between
consecutive position fixes to increase if a directional
migration took place during that period as the fish
traveled directly from the day activity space to the
night activity space.
Day and night activity spaces
The ABODE extension (Laver 2005) for ArcMap GIS
v. 9.3 (ESRI 2008) was used to generate 95% kernel
utilization distributions (KUDs) for the 24 h GPS fix
data in order to create home range estimates. Addi-
tionally, 95% KUDs were generated for diurnal and
nocturnal GPS fixes separately to map estimates of day
and night activity spaces. The 95% KUD is a
probability distribution representing the area in which
a fish can be found 95% of the time during a tracking
event (Tolimieri et al. 2009). An Overlap Index (OI;
modified from McKibben and Nelson 1986; Morrissey
and Gruber 1993) was calculated in order to ascertain
the degree of spatial segregation between Haemulon
sciurus and Lutjanus apodus diurnal and nocturnal
activity spaces. The formula for OI was calculated as:
OI ¼ O
ðA
d
þA
n
Þ
=ðA
d
þ A
n
Þð1Þ
where O
ðA
d
þA
n
Þ
is the area of overlap between the diurnal
and nocturnal activity spaces and ðA
d
þ A
n
Þ is the
combined area of the diurnal and nocturnal activity
spaces. The values range from 0.0 (no overlap, complete
segregation) to 1.0 (100% overlap, no segregation).
Thus, if day and night activity spaces are spatially
distinct then we expected a value of 0% overlap.
Spatial segregation was also characterized by mea-
suring the Euclidean distance between day and night
activity space centroids (i.e. geometric centers) with
XTools Pro 6.2.1 extension (DeLaune 2000)forArcGIS
9.3. Centroids were used because they generated single
points of reference for each day and night activity
space that could easily be used for comparisons.
Site fidelity and diel movement pathways
To compare differences in site fidelity for indi viduals
betweendayandnightaLinearityIndex(LI;
1
http://aa.usno.navy.mil/data/docs/RS_OneYear.php
Environ Biol Fish (2011) 92:525538 529
Author's personal copy
Morrissey and Gruber 1993) was calculated from the
movement paths. The LI compares site fidelity within
each activity space and was calculated as:
LI ¼ F
n
F
1
ðÞ=D ð2Þ
where F
n
is the location of the last GPS fix, F
1
is the
location of the first GPS fix and D is the total distance
traveled by the fish. The index ranges between 0.0
(site attachment) and 1.0 (roaming). We expected the
LI to be lower during the day than at night if day was
a resting period and night was a period of active
searching and foraging. In addition, differences in the
step length between day and night activity spaces
were calculated and compared with higher step length
at night indicative of more extensive movements
associated with foraging.
Statistical analysis
H. sciurus and L. apodus step lengths, recorded
during four time periods (i.e. day, sunset, night,
sunrise), were compared using generalized linear
mixed models (GLMM) (lme4 l ibrary (R 2.11.1
software, R Development Core Team 2010). Step
length was included as the dependent variable (with
Poisson error distribution), species and time period as
fixed factors and species tag identification was
included in the model as a random factor. The effect
of fixed factors was evalua ted by model selection and
likelihood ratio test (LRT), while the random factor
(species tag identification) was included as a variance
component, rather than as a factor of interest.
Interspecific comparisons of activity space centroid
distances a nd fi sh tot al l engt hs wer e mad e usin g
Students t-tests o r the ir ana logo us non-parametric
tests (MannWhitney U-test). Int raspecific compar-
isons were also made between day and night
activity space areas and site f idel ity measur es (i.e.
LI) using paired t-tests or Wilcoxon Signed Ranks
tests ( non- par ametr ic analog). The allo met ric rela-
tionship between fish total length and day and night
activity space size was evaluated using linear
regression analysis.
H. sciurus and L. apodus step length and activity
spaceareawerelog
10
transformed and LI data were
arcsine square-root transformed prior to analysis. Non-
parametric MannWhitney U or W ilcoxon signed rank
analyses were used for day and night LI comparisons if
data failed to meet parametric assumptions of normality
and/or homogeneity of variance. All statistical analyses
were performed with JMP v. 8.0.1 (SAS institute, Inc.)
and GraphPad Prism (GraphPad Software, Inc.).
Results
Sun-synchronous migrations
There was a significant random effect of species tag
ID on the model results (χ
2
=30.7, P<0.001; LRT).
There was no effect of species on step length and
consequently there were no clear differences in the
step lengths between H. sciurus and L. apodus (χ
2
=
0.009, P=0.976; LRT; Fig. 3a, b). There was a
significant effect of time period on step lengths (χ
2
=
96.9, P<0.001; LRT), with higher mean step length
values occurring at sunset and the lowest occurring
during the day (Fig. 3a, b). Thus, sun-synchronous
migrations were detected and hypothesis H
1
was
accepted.
Day and night activity spaces
Activity space areas ranged from 175 m
2
to 25 267 m
2
for H. sciurus and from 167 m
2
to 19 460 m
2
for L.
apodus (Table 1). Mean night activity space areas were
significantly larger than mean day activity space
areas for both species (H. sciurus:pairedt-test,
t=2.904, p=0.034; L. apodus:pairedt-test, t=6.177,
p=0.002). In fact, eleven out of the 12 estimated
night activity spaces were at least two times larger than
their corr es pon di ng d ay ac ti vi ty spaces (Tabl e 1).
When day and night activity space areas were
combined for each individual, there were no significant
differences between H. sciurus and L. apodus mean
daily activity space areas (Students t-test: t=0.0654,
p=0.948).
H. sciurus and L. apodus total body lengths (TL,
Table 1) were statistically similar (Students t-test:
t=1.215, p=0.252) and were pooled for allometric
analysis. No significant relationship was found between
TL and the size of day, night or total daily activity spaces
(R
2
=0.04, 0.03 and 0.06, p>0.1 respectively).
Spatial segregation of activity spaces
The hypothesis that day and night activity spaces are
spatially discrete was rejected for 9 of 12 individuals.
530 Environ Biol Fish (2011) 92:525538
Author's personal copy
All of the H. sciurus individuals exhibited some
overlap between day and night activity s paces
(Table 1). For three of the individual L. apodus,
however, day and night activity spaces were non-
overlapping and entirely spatially segregated (Table 1).
The a mount of overlap between day and night
activity spaces varied greatly between the two
species and amongst the nine individuals with
overlap (Table 1 ) . The l argest areal overlap between
diurnal and nocturna l activity sp ace s was 3816 m
2
for H. sciurus, whereas the largest overlap for L.
apodus was 627 m
2
(Tabl e 1). Yet, these v al ues each
represented <20% of the combined day and night
activity space areas for those H. sciurus and L.
apodus individuals (Table 1).
Comparison of the Overlap Index (OI) data
revealed relatively low values for all individuals in
the study (Table 1). The highest OI value was also
displayed by an H. sciurus individual (H2; Table 1).
Overall, the mean OI for H. sciurus was approxi-
mately double that of L. apodus and the mean overlap
area for H. sciurus was approximately 456% greater
than that of L. apodus. When examining the distances
between the centroids of day and night activity spaces
we report a wide range between the smallest and
largest centroid distance values for both H. sciurus
and L. apodus (Table 1). H. sciurus and L. apodus had
statistically similar mean centroid distances (H. sciu-
rus:182.4±54.6;L. apodus: 199.5±83.1; Students
t-test: t=0.172, p=0.867).
Site fidelity and diel movement behavior
LI was not significantly different for day versus night
activity spaces for either species (H. sciurus: paired
t-test: t=1.755, p=0.140; L. apodus: Wilcoxon Signed
Rank test: Z = 0. 105, p =1.000), there fore we
rejected H
3
(a). However, all of the mean LI values
were 0.06 indicating a very high degree of revisitation
to certain areas within both day and night activity
spaces. The LI values observed for H. sciurus and L.
apodus exhibited a broad range during diurnal and
nocturnal periods (Table 2). When H. sciurus diurnal
and nocturnal LI was compared to L. apodus diurnal and
nocturnal LI there was neither a significant difference
between diurnal L I (Students t-test: t= 0.0333,
p=0.974) nor between nocturnal LI (MannWhitney
U-test: U=8.000, p=0.132), respectively. There was
also no significant difference between H. sciurus and L.
apodus LI when diurnal and nocturnal data were pooled
(MannWhitney U-test: U=44.000, p=0.112).
Step length analysis of day versus night movement
behavior revealed that eleven of the twelve fish
tracked exhibited movement paths with greater step
length at night than during the day indicative of
foraging behavior (Fig. 4a, b). In fact, the mean total
distances traveled (D) within night movement path-
ways were more than double those recorded during
Fig. 3 Step lengths of two reef fishes a) H. sciurus and b) L.
apodus recorded during 24 h continuous acoustic tracking
events. Step lengths were grouped by time blocks (i.e. day,
sunset, night and sunrise) highlighting the increase in move-
ments during twilight periods (i.e. sunset and sunrise). Dots
represent the mean step lengths recorded for the six individuals
of each species with error intervals of ±1 SE. Dashed lines join
dots of the same individual. There was a significant time period
effect (Generalized Linear Mixed Model, GLMM, p=< 0.001)
Environ Biol Fish (2011) 92:525538 531
Author's personal copy
the day for both species (Table 2). Furthermore, night
step length was significantly greater than day step
length for both H. sciurus and L. apodus (Dunns Test,
p<0.05), therefore, we accepted hypothesis H
3
(b).
Table 1 Comparison of area, distance and overlap between
Haemulon sciurus and Lutjanus apodus day and night activity
spaces estimated using 95% fixed kernel utilization distribu-
tions. The Overlap Index represents the ratio of the area of
overlap between day and night activity spaces over the sum of
day and night activity space areas. The centroid distance is the
Euclidean distance between the day activity space centroid and
the night activity space centroid
Fish ID Bay Tag date Track date Total
length (cm)
Day activity
space (m
2
)
Night activity
space (m
2
)
Day+
night (m
2
)
Overlap
area (m
2
)
Overlap
index (OI)
Centroid
distance (m)
H. sciurus
1 Lameshur 7/13/08 7/14/08 24.5 12486 8836 21322 3816 0.179 70.2
2 Lameshur 10/9/08 10/23/08 29.7 281 608 889 278 0.312 2.4
3 Lameshur 6/2/09 6/4/09 29.5 175 12619 12794 12 0.001 187.6
4 Brewers 8/1/09 8/26/09 30.6 284 15664 15947 284 0.018 332.7
5 Brewers 9/16/09 9/30/09 29.3 764 4861 5626 663 0.118 171.8
6 Brewers 3/25/10 4/6/10 29.0 2677 25267 27944 1226 0.044 329.6
Mean
(SE)
28.8
(0.9)
2778
(1979)
11309
(3548)
14087
(4063)
1047
(580)
0.112
(0.048)
182.4
(54.6)
L. apodus
1 Lameshur 1/8/09 1/13/09 38.3 332 2652 2983 332 0.111 9.5
2 Lameshur 4/9/09 4/22/09 29.5 627 2859 3486 627 0.180 11.0
3 Lameshur 6/2/09 6/11/09 30.1 1700 19460 21159 0 0.000 485.7
4 Brewers 8/1/09 9/2/09 33.1 4277 19185 23462 0 0.000 360.2
5 Brewers 12/9/09 12/14/09 25.1 167 9063 9231 0 0.000 277.9
6 Brewers 1/2/10 1/9/10 31.0 644 6482 7127 419 0.059 52.7
Mean
(SE)
31.2
(1.8)
1291
(636)
9950
(3120)
11241
(3638)
230
(110)
0.058
(0.030)
199.5
(83.1)
Day Night
Fish ID (F
n
-F
1
) D LI (F
n
-F
1
)D LI
H. sciurus
1 127.7 889.9 0.14 32.4 378.1 0.09
2 13.9 325.5 0.04 5.8 531.3 0.01
3 1.5 273.9 0.01 19.9 2610.4 0.01
4 4.6 338.5 0.01 17.8 1714.8 0.01
5 4.6 517.7 0.01 11.5 1298.4 0.01
6 26.8 945.8 0.03 43.7 1855.6 0.02
Mean (SE) 548.6 (121.9) 0.04 (0.02) 1398.1 (345.5) 0.02 (0.01)
L. apodus
1 6.2 259.9 0.02 18.7 1643.1 0.01
2 8.7 407.7 0.02 15.3 893.8 0.02
3 20.9 326.3 0.06 119.5 2351.6 0.05
4 20.2 933.8 0.02 89.8 2021.4 0.04
5 4.4 188.9 0.02 337.3 1517.4 0.22
6 19.5 483.6 0.04 22.4 1305.5 0.02
Mean (SE) 433.4 (108.8) 0.03 (0.01) 1622.1 (210.8) 0.06 (0.03)
Table 2 Linearity Indices
(LI) calculated for six
Haemulon sciurus and six
Lutjanus apodus individuals
from GPS fixes taken
during day and night.
LI = (F
n
-F
1
)/D, F
n
= last
GPS fix, F
1
= first GPS fix,
D = total displacement
(total distance traveled
in meters)
532 Environ Biol Fish (2011) 92:525538
Author's personal copy
Fig. 4 Plots of twelve individual a) Haemulon sciurus (H1-6)
and b) Lutjanus apodus (L1-6) step lengths recorded during
24 h continuous acoustic tracking events. Step length is the
Euclidean distance between two consecutive detections. Dashed
lines indicate sunset and sunrise times. Gaps in plot are periods
where GPS position fixes could not be obtained based on 85%
signal strength requirement
Environ Biol Fish (2011) 92:525538 533
Author's personal copy
Discussion
Coupling acoustic telemetry techniques with GIS
tools and spatial statistics to track, map and quantify
the movement behavi ors of two common Caribbean
coral reef species has provided high temporal resolu-
tion, quantitative and spatially explicit information on
two common Caribbean fish species. In addition, we
provide direct confirmation of the existence of highly
directional sun-synchronous diel migrations. Our
study also re vea led that although distinc tive diel
migrations and diel space use patterns exist, we
highlighte d important intra- and inter-species vari-
ability in movement behavior highlighting the
complexity of f ish moveme nt ecology across coral
reef seascapes.
Sun-synchronous migrations
Statistical detection of increased step length during
crepuscular periods, through directional movements to
and from night activity spaces confirmed the existence
of sun-synchronous diel migrations. Detailed records of
the pre ci se timing of sun-sync hr onou s migrat io ns
have been documented for other speci es fr om the
haemulid family. French (H. flavolineatum)and
white grunts (H. plumierii) performed consistently
scheduled and highly ritualized pre-migration behav-
iors that eventually led to migrations into adjacent
seagrass beds approximately 2030 min after sunset
and before sunrise (Ogden and Ehrlich 1977;McFarland
et al. 1979). McFarland et al. (1979) proposed that
absolute light irradiance levels, the rat e of light
intensity changes and endogenous rhythms were all
potential cues for the precision of t he migrations.
The ecologi cal motivation behind the timing of these
and other types of migratio ns has been attributed to
predator avoidance (i.e., sharks and other l arge-
bodied piscivorous fish), or simply a reduction in
predation risk (McFarland et al. 1979; Claydon
2004). In the Virgin I slands, Gladfelter (1979)
observed peak predator activity between sunset and
the end of twilight (25 to 30 min after sunset). Our
acoustic tracking in the U.S. Virgin Islands detected
H. sciurus and L. apodus migrations that commenced
during the hour following sunset and the hour prior
to sunrise, which is a lso consistent with scheduling
documented for a range of fish species in neighbor-
ing Puerto Rico (Rooker and Dennis 1991). Never-
theless, fish in our study di d not strictly adhere to the
same migration schedules witnessed in other studies
of grunts. In fact, some of the migrations took place
within the quiet period (Fig. 4a, b) and may indicate
greater plasti city in the sun- sync hron ous sch edu ling
than was e vi dent in earlier studi es in the 1970s and
1980s. It is not certain whether this difference is
methodological (i.e. remote tracking versus in-situ
human observations) or reflects a reduction in the
risk from predation due to removal of large piscivorous
fish populations from the Caribbean region (Paddack et
al. 2009;Stallings2009).
Overall, H. sciurus and L. apodus exhibited similar
trends in their sun-synchronous migration behaviors.
However, the timing of H. sciurus migrations appeared
to deviate less from the calculated sunrise and sunset
times than L. apodus migrations, except for the three L.
apodus individuals (discussed below) that had com-
pletely segregated day and night activity spaces. L.
apodus
often feed opportunistically throughout the day
within their resting habitats (Rooker 1995; Verweij et
al. 2007), implying that nocturnal foraging migrations
into seagrass beds may be facultative rather than
obligate. This difference may also be indicative of a
more generalist seascape use strategy for L. apodus.
Further research is required to compare diel space use
patterns in areas with a very different abundance of
known predators.
Day and night activity spaces
The use of significantly larger nocturnal activity spaces
by H. sciurus and L. apodus is indicative of more
extensive searching behavior associated with foraging.
Haemulids and lutjanids are known to forage noctur-
nally (Stark and Davis 1966; Ogden and Zieman 1977)
and typically reside in shelters diurnally (Robblee and
Zieman 1984; Rooker and Dennis 1991; Beets et al.
2003). Maximum linear movements of H. sciurus and
L. apodus from release sites or locations of re-sightings
have documented them traveling distances up to 767 m
and 325 m, respectively (Beets et al. 2003; Verweij et
al. 2007). Our study has demonstrated that within 24 h
these two species are capable of moving much greater
distances traversing substantial areas of the seascape.
Contrary to other fish species associated with coral reef
species (e.g. Morrissey and Gruber 1993;Kramerand
Chapman 1999), we found no allometric relationship
between H. sciurus and L. apodus total lengths and the
534 Environ Biol Fish (2011) 92:525538
Author's personal copy
size of activity spaces. While we acknowledge that
tracking a broader range of size classes may reveal a
different result, we argue that underlying mechanisms,
such as, resource partitioning (e.g. Ogden and Ehrlich
1977; Ogden and Zieman 1977), prey availability, and
seascape composition and configuration (e.g. Pittman et
al. 2007; Hitt et al. 201 1) could be stronger determi-
nants of activity space area for these species. Else-
where, Lowe et al. (2003) found no relationship
betweensizeofkelpbassandhomerangeareaoffering
that seasonality, differential space use between fish
sexes, access to habitat, and spawning activity, likely
caused uneven home range areas. Further investigations
into allometric relationships with space use patterns are
needed in order to form appropriate a nd r obust
conclusions.
Spatial segregation of activity spaces
Spatial segregation of activity spaces appeared to be
heavily influenced by the distribution of habitat types
at the tracking sites whereby the proximity of
nocturnal feeding grounds to diurnal shelter habitats
differs between Brewers and Lameshur Bays (Hitt et
al. 2011). The difference in individual space use
patterns was highlighted by fewer instances of
overlap between diurnal and nocturnal activity spaces
(i.e. lower OI values) within Brewers Bay than
Lameshur Bay. In Lameshur Bay seagrasses exist
in close proximity to nearly all coral reef and
boulder (i.e. shelter) habitats within the bay, a
spatial arrangement of habitats that likely requires
shorter foraging migrations and, thus, resulted in
greater over lap of day/ nigh t activity sp ace s. The
importance of seagr as s beds as fo ra gi ng habitat f or
haemulids and lutjanids has been well documented
elsewhere ( e.g. Meyer and Schultz 1985;Burke
1995; Verweij et al. 2007)
Site fidelity and diel movement pathways
Our findings suggest very high site fide lity a nd
extensive revisitation to preferred habitats within day
and night activity spaces, the latter of which may be
explained by confined diurnal resting/sheltering behav-
ior coupled with broad nocturnal foraging behavior. This
behavior has been observed in aggregations of French
(H. flavolineatum) and white grunts (H. plumierii)that
demonstrated consistent, long-term (> 2 years) site
fidelity toward specific coral heads in St. Croix, while
resting during the day (Meyer et al. 1983; Meyer and
Schultz 1985). Ogden and Ehrlich (1977) observed
groups of French and white grunts systematically
leaving their daytime shelters at twilight to forage in
nearby seagrass beds where they separated to adopt
convoluted individual foraging movements at night.
Diel movement paths and site fidelity behaviors have
been described for other grunt species (e.g. Ogden and
Ehrlich 1977; Ogden and Zieman 1977;McFarlandet
al. 1979; Helfman et al. 1982), in which body size
appeared to play a role in determining site fidelity and
movement pathways of juveniles. Medium sized (15
30 mm, TL) juveniles exhibited stronger site fidelity to
rock outcrops or Diadema spp. than other size classes
and moved along borders and channels within the
seagrass beds, whereas small individuals (1015 mm,
TL) exhibited transient movement patterns with no
clear migration behavior (Helfman et al. 1982). We
observed comparable patterns in this study; high site
fidelity to shelter (i.e. boulders) and migration paths
that followed coral reef edges and channels between
habitat types (see also Hitt et al. 2011); although the
edge use behavior was not distinguished within the
more homogeneous seagrass habitats. The complex
movement behavior of H. sciurus and L. apodus may
involve the use of route specific landmarks and/or
cognitive maps as observed for individual butterflyfish
navigating over highly structured coral reefs (Reese
1989). However, finer temporal resolution tracking and
high resolution seafloor mapping is required to
elucidate further on the use of bathymetric features in
fish navigation.
There are few studies that have recorded data
pertaining to site fidelity or between-habitat movement
for H. sciurus or L. apodus (e.g. Beets et al. 2003;
Verweij and Nagelkerken 2007; Verweij et al. 2007).
For H. sciurus, Beets et al. (2003)reportedhighsite
attachment to diurnal reef habitats and high site fidelity
within seagrass foraging areas. Burke (1995)alsore-
sighted H. sciurus at specific feeding locations within
seagrass beds on several occasions and at daytime
shelters each morning following a migration. Site
fidelity of tagged H. sciurus was documented by
Verweij and Nagelkerken (2007) who calculated a
core area of presence (CAP) (i.e., segment of belt
transect with highest number of resightings) and found
that 62% of the individuals re-sighted were found
within 10 m of the CAP. Similarly, Verweij et al. (2007)
Environ Biol Fish (2011) 92:525538 535
Author's personal copy
used a CAP to define site fidelity for L. apodus and
found that 80% of all resightings were within 10 m of
the CAP. While some form of measurement was
recorded for movements between habitats in all of the
above studies, detailed movement pathways were not
provided.
Stark and Davis (1966) emphasized caution when
making generalizations relative to feeding times
across species as many exceptions and overlaps exist
among trophic categories. We propose that the lack of
significant differences between day and n ight site
fidelity may be explained by more subtle differences
in individual H. sciurus and L. apodus diel movement
and foraging behavior.
Limitations and future directions
Determining an appropriate temporal resolution for
the sampling protocol in any acoustic telemetry study
presents many challenges, typically because of logis-
tical constraints, yet should be based on a time frame
appropriate for the research quest ions (Otis and White
1999: Cushman 2009) or based on the ecology of the
organism under investigation. Here, each fish was
tracked for one 24 h period so that day, night and
crepuscular movements could be detected; however,
future studies may expand this duration to include
several days to examine variability in daily migration
behaviors and space use patterns. In addition to the
sampling interval, location error specific to the type of
tracking technology used (Bradshaw et al. 2007) and
battery life of the acoustic transmitters may reduce the
researchers ability to detect behavioral movement
patt erns. The use of GPS technol ogy to capture
location fixes and continuous acoustic transmitters with
rapid ping intervals, therefore, limited the spatial
resolution of our data to a few meters and narrowed
the window for tag detection following implantation to~
30 days. Modern applications of acoustic telemetry via
passive/autonomous acoustic arrays now allow for
three-dimensional triangulation of transmitter locations
with a high degree of spatial accuracy (< 1 m) (e.g.
Rillahan et al. 2009). Coupled with the continued
miniaturization of acoustic transmitters, passive array
technology has begun to address many of the limi-
tations and concerns experienced in traditional move-
ment behavior studies, meanwhile, providing an
avenue for detailed analyses of fish movement ecology
in the future.
Acknowledgements This research was supported by a
NOAA cooperative agreement with the University of the
Virgin Islands. We thank the staff of NOAAs Biogeography
Branch for providing logistical support and acoustic tracking
equipment and the N ational Park Service on St. John for
their cooperation while operating within the Virgin Islands
National Park. We wo uld also like to thank th e numerous
UVI volunteers who helped to collect the 288 h of fish
tracking data in all weather conditions. Finally, we would
like to extend our gratitude to the anonymous reviewers o f
this manuscript for their constructive comments.
References
Beets J, Muehlstein L, Haught K, Schmitges H (2003) Habitat
connectivity in coastal environments: patterns and move-
ments of Caribbean coral reef fishes with emphasis on
bluestriped grunt, Haemulon sciurus. Gulf Caribb Res
14:2942
Bell WJ, Kramer E (1979) Search and anemotactic orientation
of cochroaches. J Insect Physiol 25:631640
Beyer HL (2004) Hawth's Analysis Tools for ArcGIS (version
9/18/2007). http://www.spatialecology.com/htools
Bradshaw CJA, Sims DW, Hays GC (2007) Measurement error
causes scale-dependent threshold erosion of biological
signals in animal movement data. Ecol Appl 17:628638
Burke NC (1995) Nocturnal foraging habitats of French and
bluestriped grunts, Haemulon flavolineatum and H. sciurus,
at Tobacco Caye, Belize. Environ Biol Fish 42:365374
Childs A-R, Booth AJ, Cowley PD, Potts WM, Næsje TF,
Thorstad EB, Økland F (2008) Home range of an estuarine-
dependent fish species Pomadasys commersonnii in a South
African estuary. Fish Mgmt Ecol 15:441448
Clark RD, Pittman S, Caldow C, Christensen J, Roque B,
Appeldoorn RS, Monaco ME (2009) Nocturnal fish move-
ment and trophic flow across habitat boundaries in a coral reef
ecosystem (SW Puerto Rico). Carib J Sci 45(2-3):282303
Claydon J (2004) Spawning aggregations of coral reef fishes:
characteristics, hypotheses, threats and management.
Ocean Mar Biol Ann Rev 42:265302
Cocheret de la Morinière E, Pollux BJA, Nagelkerken I,
Hemminga MA, Huiskes AHL, van der Velde G (2003a)
Ontogenetic dietary changes of coral reef fishes in the
mangrove-seagrass-reef continuum: stable isotopes and
gut-content analysis. Mar Ecol Prog Ser 246:279289
Cocheret de la Morinière E, Pollux BJA, Nagelkerken I, van
der Velde G (2003b) Diet shifts of Caribbean grunts
(Haemulidae) and snappers (Lutjanidae) and the relation
with nursery-to-coral reef migrations. Est Coast Shelf Sci
57:10791089
Cushman SA (2009) Animal movement data: GPS telemetry,
autocorrelation and the need for path-level analysis. In:
Cushman SA, Huettmann F (eds) Spatial complexity,
informatics, and wildlife conservation. Springer, New
York, pp 131149
Dahlgren CP, Eggleston DB (2000) Ecological processes
underlying ontogenetic habitat shifts in a coral reef fish.
Ecology 81:22272240
536 Environ Biol Fish (2011) 92:525538
Author's personal copy
DeLaune MG (2000) XTools ArcMap Extension (Version 10/
18/2000). http://www.xtoolspro.com
Dubin RE, Baker JD (1982) Two types of cover-seeking
behavior at sunset by the pr incess parrotfish, Scarus
taeniopterus, at Barbados, West Indies. Bull Mar Sci
32:572583
Getz WM, Saltz D (2008) A framework for generating and
analyzing movement paths on ecological landscapes. Proc
Nat Acad Sci 105:1906619071
Gladfelter WB (1979) Twilight migrations and foraging
activities of the copper sweeper Pempheris schomburgki
(Teleostei: Pempheridae). Mar Biol (Berl) 50:109119
Halpin PM (2000) Habitat use by an intertidal salt-marsh fish:
trade-offs between predation and growth. Mar Ecol Prog
Ser 198:203214
Hammerschlag N, Heithaus MR, Serafy JE (2010a) Influence
of predation risk and food supply o n nocturnal fish
foraging distributions along a mangrove-seagrass ecotone.
Mar Ecol Prog Ser 414:223235
Hammerschlag N, Morgan AB, Serafy JE (2010b) Relative
predation risk for fishes along a subtropical mangrove-
seagrass ecotone. Mar Ecol Prog Ser 401:259267
Helfman GS, Meyer JL, McFarland WN (1982) The
ontogeny of twilight migration patterns in grunts
(Pisces: Haemulidae). Anim Behav 30:31 732 6
Hitt S, Pittman SJ, Nemeth RS (2011) Fish movement behavior
is linked to benthic seascape structure in a Caribbean coral
reef ecosystem. Mar Ecol Prog Ser 427: 275291
Hobson ES (1973) Diel feeding migrations in tropical reef
fishes. Helgoländer wiss Meeresunters 24:361370
Kramer DL, Chapman MR (1999) Implications of fish home
range size and relocation for marine reserve function.
Environ Biol Fish 55:6579
Krumme U (2009) Diel and tidal movements by fish and decapods
linking tropical coastal ecosystems. In: Negelkerken I (ed)
Ecological connectivity among tropical coastal ecosystems.
Springer, New York, pp 271324
Laver P (2005) ABODE: kernel home range estimation for ArcGIS,
using VBA and ArcObjects. User manual (Beta v. 27)
Lowe CG, Topping DT, Cartamil DP, Papastamatiou YP
(2003) M ovement patterns, home range, and habitat
utilization of adult kelp bass Paralabrax clathratus in a
temperate no-take marine reserve. Mar Ecol Prog Ser
256:205216
McFarland WN, Ogden JC, Lythgoe JN (1979) The influence
of light on the twilight migrations of grunts. Environ Biol
Fish 4:922
McKibben JN, Nelson DR (1986) Patterns of movement and
grouping of gray reef sharks, Carcharhinus amblyrhyn-
chos, at Enewetak, Marshall Islands. Bull Mar Sci 38:89
110
Meyer CG, Holland KN, Wetherbee BM, Lowe CG (2000)
Movement patterns, habitat utilization, home range size
and site fidelity of whitesaddle goatfis h, Parupeneus
porphyreus, i n a marine reserve. Environ Biol Fish
59:235242
Meyer JL, Schultz ET, Helfman GS (1983) Fish schools: an
asset to corals. Science 220:10471049
Meyer JL, Schultz ET (1985) Migrating haemulid fishes as a
source of nutrients and organic matter on coral reefs.
Limnol Ocean 30:146
156
Monaco ME, Friedlander AM, Caldow C, Christensen JD, Rogers
C, Beets J, Miller J, Boulon R (2007) Characterizing reef fish
populations and habitats with and outside the US Virgin
Islands Coral Reef National Monument: a lesson in marine
protected area design. Fish Mgmt Ecol 14:3340
Morrissey JF, Gruber SH (1993) Home range of juvenile lemon
sharks, Negaprion brevirostris. Copeia 1993:425434
Nagelkerken I, Dorenbosch M, Verberk WCEP, Cocheret de la
Morinière E, van der Velde G (2000) Daynight shifts of
fishes between shallow-water biotopes of a Caribbean bay,
with emphasis on the nocturnal feeding of Haemulidae and
Lutjanidae. Mar Ecol Prog Ser 194:5564
Nathan R, Getz WM, Revilla E, Holyoak M, Kadmon R, Saltz
D, Smouse PE (2008) A movement ecology paradigm for
unifying organismal movement research. Proc Natl Acad
Sci 105:1905219059
Ogden JC, Buckman NS (1973) Movements, foraging groups,
and diurnal migrations of the striped parrotfish Scarus
croicensis Bloch (Scaridae). Ecology 54:589596
Ogden JC, Ehrlich PR (1977) The behaviour of heterotypic
resting schools of juvenile grunts (Pomadasyidae). Mar
Biol 42:273280
Ogden JC, Zieman JC (1977) Ecological aspects of coral reef-
seagrass bed contacts in the Caribbean. In: Proc 3rd Int
Symp Coral Reefs, (1, Biology), pp 377382
Ortega LA, Heupel MR, van Beynen P, Motta PJ (2009)
Movement patterns and water quality preferences of
juvenile bull sharks (Carcharhinus leucas) in a Florida
estuary. Environ Biol Fish 84:361373
Otis DL, White GC (1999) Autocorrelation of location
estimates and the analysis of radio tracking data. J Wildl
Manag 63:10391044
Paddack MJ, Reynolds JD, A guilar C, Appeldoorn RS, Beets
J, Burkett EW, Chittaro PM, C larke K, Esteves R,
Fonseca AC, Forrester GE, Friedlander AM, García-Sais
J, González-Sansón G, Jordan LKB, McClellan DB,
Miller MW, Molloy PP, Mumby PJ, Nagelkerken I,
Nemeth M, Navas-Camacho R, Pitt J , Polunin NVC,
Reyes-Nivia MC, Robertson DR, Rodrígu ez-Ramírez A,
Salas E, Smith SR, Spieler RE, Steele MA, Williams
ID, Wormald CL, Watkinson AR, Côté IM (2009)
Recent region-wide declines in caribbean reef f ish
abundance. Curr Biol 19:590595
Papastamatiou YP, Lowe CG, Caselle JE, Friedlander AM
(2009) Scale-dependent effects of habitat on movements
and path structure of reef sharks at a predator-dominated
atoll. Ecology 90:9961008
Pittman SJ, McAlpine CA (2003) Movement of marine fish and
decapod crustaceans: process, theory and application. Adv
Mar Biol 44:205294
Pittman SJ, Caldow C, Hile SD, Monaco ME (2007) Using
seascape types to explain the spatial patterns of fish in the
mangroves of SW Puerto Rico. Mar Ecol Prog Ser
348:273284
R_Development_Core_Team (2010) R: A language and envi-
ronment for statistical computing. R Foundation for
Statistical Computing, Vienna
Reese ES (1989) Orientation behavior of butterflyfishes (family
Chaetodontidae) on coral reefs: spatial learning of route
specific landmarks and cognitive maps. Environ Biol Fish
25:7986
Environ Biol Fish (2011) 92:525538 537
Author's personal copy
Rillahan C, Chambers M, Howell WH, Watson WH III (2009)
A self-contained system for observing and quantifying the
behavior of Atlantic cod, Gadus morhua, in an offshore
aquaculture cage. Aquaculture 293:4956
Robblee MB, Zieman JC (1984) Diel variation in the fish fauna
of a tropical seagrass feeding ground. Bull Mar Sci
34:335345
Rooker JR (1995) Feeding ecology of the schoolmaster
snapper, Lutjanus apodus (Walbaum), from southwestern
Puerto Rico. Bull Mar Sci 56:881894
Rooker JR, Dennis GD (1991) Diel, lunar and seasonal changes
in a mangrove fish assemblage off southwestern Puerto
Rico. Bull Mar Sci 49:684698
Sale PF, Cowen RK, Danilowicz BS, Jones GP, Kritzer JP,
Lindeman KC, Planes S, Polunin NVC, Russ GR, Sadovy
YJ, Steneck RS (2005) Critical science gaps impede use of
no-take fishery reserves. Trends Ecol Evol 20:7480
Stallings CD (2009) Fishery-independent data reveal negative
effect of human population density on Caribbean predatory
fish communities. PLoS One 4:e5333
Stark WA II, Davis WP (1966) Night habits of fishes of
Alligator Reef, Florida. Ichthyol Aquarium J 38:313356
Tolimieri N, Andrews K, Williams G, Katz S, Levin PS
(2009) Home r ange size and patterns of space use by
lingcod, copper rockfish and quillback rockfish in
relation to diel and tidal cycles. Mar Ecol Prog Ser
380:229243
Topping DT, Lowe CG, Caselle JE (2005) Home range and
habitat utilization of adult California sheephead, Semi-
cossyphus pulcher (Labridae), in a temperate no- take
marine reserve. Mar Biol 147:301311
Tulevech SM, Recksiek CW (1994) Acoustic tracking of adult
white grunt, Haemulon plumierii, in Puerto Rico and
Florida. Fish Res 19:301319
Turchin P (1998) Quantitative analysis of movement: measur-
ing and modeling population redistribution in individuals
and plant. Sinauer Associates, Sunderland
Verweij MC, Nagelkerken I (2007) Short and long-term movement
and site fidelity of juvenile Haemulidae in back-reef habitats
of a Caribbean embayment. Hydrobiologia 592:257270
Verweij MC, Nagelkerken I, Hol KEM, van den Beld AHJB,
van der Velde G (2007) Space use of Lutjanus apodus
including movement between a putative nursery and a
coral reef. Bull Mar Sci 81:127138
538 Environ Biol Fish (2011) 92:525538
Author's personal copy
... The movement patterns of animals examined in the context of their surroundings reveal central aspects of their life history and resource needs. Coral reef sh, in particular, live in highly heterogeneous environments, making diel movements between habitat types in order to balance predation risk, foraging bene ts, and competition avoidance [1,2]. The mosaic of habitats inhabited by a sh comprises their home range, an area regularly utilized for feeding and shelter [3]. ...
... For general long-term, coarse-scale movement patterns and space utilization analysis, passive acoustic telemetry is a well-suited method [7], which allows the tracking of many sh continuously over a long period of time [8,9]. This technology can help identify important parameters of sh ecology and life history such as diel changes in space use [1,4,10,11], habitat association [12,13], site delity [14], residence time [15], and seasonal migrations [16]. ...
... Lutjanid abundance is higher in speci c edge habitats, such as areas with abundant patch reefs and large amounts of seagrass [6,17], presumably because the proximity of usable resources signi es higher-quality habitat than structure alone [18]. Lutjanids and Haemulids have been shown to predictably use multiple habitats within a day, performing diel movements between coral reefs, where they shelter during the day, and seagrasses, where they forage at night [1,4,19]. Therefore, an individual's home range would be expected to contain a large proportion of each of these habitats, with daytime and nighttime activity spaces dominated by coral reef and seagrass habitats, respectively. ...
Preprint
Full-text available
Background: The movement ecology of mutton snapper Lutjanus analis is poorly understood despite their ecological and economic importance in the Caribbean. Passive acoustic telemetry was used to determine home ranges of six adult L. analis, including diel patterns, in Brewers Bay, St. Thomas, US Virgin Islands. Understanding long-term space use, including site fidelity and habitat usage, is necessary to implement effective and appropriate management actions for a species with extensive space and resource needs. Results: Individual L. analis were tracked over an average period of 316 days (range 125 - 509 days) and showed high site fidelity to relatively small home ranges (mean ± SD: 0.103 ± 0.028 km², range 0.019 - 0.190 km²) and core use areas with low overlap among individuals. Most home ranges had a habitat composition dominated by seagrass and to a lesser degree, coral reef and/or pavement. Nighttime activity spaces were distinct from but contained within daytime areas. Conclusions: Mutton snapper showed strong site fidelity to home ranges in Brewers Bay. Two individuals that were absent from the array for more than a few hours were detected at separate arrays at spawning aggregation sites. This study expands upon knowledge of mutton snapper home range characteristics, highlights the importance of maintaining adjacent high-quality habitat types in any spatial management plan, and encourages the adoption of other types of management strategies, particularly for transient-aggregating species.
... The movement patterns of animals examined in the context of their surroundings reveal central aspects of their life history and resource needs. Coral reef fish, in particular, live in highly heterogeneous environments, making diel movements between habitat types in order to balance predation risk, foraging benefits, and competition avoidance [1]. The mosaic of habitats inhabited by a fish comprises their home range, an area regularly utilized for feeding and shelter [2]. ...
... It has no effect of observer presence, allows the tracking of many fish continuously over a long period of time [5,6], and movement patterns can be linked to other environmental variables such as temperature or tidal phase [7]. This technology can help identify important parameters of fish ecology and life history, such as diel changes in space use [1,3,8,9], habitat ...
... Animal Biotelemetry *Correspondence: sarah.heidmann@uvi.edu 1 Center for Marine and Environmental Studies, University of the Virgin Islands, 2 John Brewers Bay, St. Thomas, VI 00802, USA Full list of author information is available at the end of the article association [10,11], site fidelity [12], residence time [13], and seasonal migrations [14]. ...
Article
Full-text available
Background The movement ecology of mutton snapper Lutjanus analis is poorly understood despite their ecological and economic importance in the Caribbean. Passive acoustic telemetry was used to determine home ranges of six adult L. analis , including diel patterns, in Brewers Bay, St. Thomas, US Virgin Islands. Understanding long-term space use, including site fidelity and habitat usage, is necessary to implement effective and appropriate management actions for a species with extensive space and resource needs. Results Individual L. analis were tracked over an average period of 316 days (range 125–509 days) and showed high site fidelity to relatively small home ranges (mean ± SD: 0.103 ± 0.028 km ² , range 0.019–0.190 km ² ) and core use areas with low overlap among individuals. Most home ranges had a habitat composition dominated by seagrass and to a lesser degree, coral reef and/or pavement. Nighttime activity spaces were distinct from but contained within daytime areas. Conclusions Mutton snapper showed strong site fidelity to home ranges in Brewers Bay. Two individuals that were absent from the array for more than a few hours were detected at separate arrays at spawning aggregation sites. This study expands upon knowledge of mutton snapper home range characteristics, highlights the importance of maintaining adjacent high-quality habitat types in any spatial management plan, and encourages the adoption of other types of management strategies, particularly for transient-aggregating species.
... The mean home range size of S. axillare was comparable to the home range estimated for S. cretense (La Mesa et al. 2012), but approximately 6 to 30 times greater than previously reported for parrotfish species using acoustic telemetry (Afonso et al. 2008, Welsh & Bellwood 2012b, Garcia et al. 2014, Davis et al. 2017. Mean home range for L. alexandrei was equivalent to that estimated for L. apodus (Garcia et al. 2014) and red snapper L. campechanus (Froehlich et al. 2019), although about 6 to 50 times greater than that observed in other studies on Lutjanus species (Hammerschlag-Peyer & Layman 2010, Hitt et al. 2011a, Topping & Szedlmayer 2011. Such differences in home range sizes might be related to specific environmental and ecological features of the different studied sites and to species-specific requirements and behavior (Zeller 1997). ...
... On the other hand, positive relationships between fish length and home range size have been reported for snappers such as L. campechanus (Topping & Szedlmayer 2011, Piraino & Szedlmayer 2014, Froehlich et al. 2019) and checkered snapper L. decussatus (Na nami & Yamada 2008), which might be attributed to an increase in resource requirements of larger in dividuals (Wakeman et al. 1979, Kramer & Chapman 1999. However, other studies on snappers have found no influence of body length on home range size (Hammerschlag-Peyer & Layman 2010, Hitt et al. 2011a), suggesting that other factors including competition (Jones 2005), individual learning and be havior (Parsons et al. 2003, Brown & Laland 2003, and seascape structure (Hitt et al. 2011b, Pittman et al. 2014) likely determine home range variability within populations. The lack of statistical significance in the results reported here are likely to have been influenced by the small number of tagged fish, which is a recurrent issue in acoustic telemetry studies (Luo et al. 2009, Hammerschlag-Peyer & Layman 2010. ...
Article
Movement is a key factor that shapes the distribution and structure of fish populations and influences the extent of the benefits provided by conservation and management measures, such as the implementation of marine no-take zones (NTZs). We used visual surveys and acoustic telemetry to investigate density and movement of 2 Brazilian endemic and highly targeted reef fish species inside and outside a coral reef NTZ, and subsequently inferred the effectiveness of the NTZ for protecting these species. To do so, visual surveys were performed on protected and unprotected reefs between 2016 and 2017. Moreover, 20 gray parrotfish Sparisoma axillare and 9 Brazilian snapper Lutjanus alexandrei were tagged with acoustic transmitters and passively monitored from December 2016 to October 2017. For both species, fish densities were significantly higher within the NTZ. Also, both species presented a high residence index over the short term, indicating they were full-time residents of the monitored area until detections were permanently lost. The absence of detections may indicate relocation to deeper reefs, predation, or fishing mortality when fish left the NTZ. Home ranges were small (0.10 to 0.45 km ² ), and both species presented spatially segregated subgroups within the populations. On average, the percentage of the home ranges within the NTZ was 88% for S. axillare and 95% for L. alexandrei . The results showed that small NTZs that are important to part of the life cycle of a target species are an effective measure to conserve reef fish populations, and also highlight the importance of fisheries management outside NTZs.
... Compared to apogonids, even less is known about the functional movement of larger nocturnal fishes on coral reefs. We know from acoustic tracking studies that these larger, high biomass families have the capacity to move great distances (Hitt, Pittman, & Brown, 2011;Hitt, Pittman, & Nemeth, 2011), however, the locations where they feed or occupy at night, in general, are poorly known, and may not be obvious from our knowledge of their diurnal habits. A clear example is the rabbitfish Siganus lineatus, which has been found to include sharp variations in diel activity between groups of individuals only a few kilometers apart (Fox & Bellwood, 2011). ...
Article
Full-text available
The ecological functions of nocturnal coral reef fishes are poorly known. Yet, nocturnal resources for coral reef consumers are theoretically as abundant and productive, if not more so, than their diurnal counterparts. In this study, we quantify and contrast the energetic dynamics of nocturnal and diurnal fishes in a model coral reef ecosystem, evaluating whether they attain similar levels of biomass production. We integrated a detailed dataset of coral reef fish counts, comprising diurnal and nocturnal species, in sites sheltered and exposed to wave action. We combined somatic growth and mortality models to estimate rates of consumer biomass production, a key ecosystem function. We found that diurnal fish assemblages have a higher biomass than nocturnal fishes: 104% more in sheltered sites and 271% more in exposed sites. Differences in productivity were even more pronounced, with diurnal fishes contributing 163% more productivity in sheltered locations, and 558% more in exposed locations. Apogonidae dominated biomass production within the nocturnal fish assemblage, comprising 54% of total nocturnal fish productivity, which is proportionally more than any diurnal fish family. The substantially lower contributions of nocturnal fishes to biomass and biomass production likely indicate constraints on resource accessibility. Taxa that overcome these constraints may thrive, as evidenced by apogonids. This study highlights the importance of nocturnal fishes in underpinning the flow of energy and nutrients from nocturnal resources to reef communities; a process driven mainly by small, cryptic fishes.
... Similar to adult tarpon, juveniles had the highest rates of movement during dawn and dusk, which suggests high feeding rates during crepuscular periods. However, this behavior may also indicate rapid movements along migration pathways between nighttime and daytime activity spaces [18,[48][49][50][51][52][53][54]. ROM was significantly slower at night than other time periods, which suggests that juvenile tarpon were not feeding at this time. ...
Article
Full-text available
Abstract Background Atlantic tarpon (Megalops atlanticus) are a highly migratory species ranging along continental and insular coastlines of the Atlantic Ocean. Due to their importance to regional recreational and sport fisheries, research has been focused on large-scale movement patterns of reproductively active adults in areas where they are of high economic value. As a consequence, geographically restricted focus on adults has left significant gaps in our understanding of tarpon biology and their movements, especially for juveniles in remote locations where they are common. Our study focused on small-scale patterns of movement and habitat use of juvenile tarpon using acoustic telemetry in a small bay in St. Thomas, US Virgin Islands. Results Four juvenile tarpon (80–95 cm FL) were tracked from September 2015 to February 2018, while an additional eight juveniles (61–94 cm FL) left the study area within 2 days after tagging and were not included in analysis. Four tarpon had > 78% residency and average activity space of 0.76 km2 (range 0.08–1.17 km2) within Brewers Bay (1.8 km2). Their vertical distribution was
... Juvenile tarpon had the highest rates of movement during dawn and dusk, but ROM was signi cantly slower at night, which suggests that juvenile tarpon were not feeding at this time. High ROM during crepuscular periods, may also indicate consistent use of migration pathways between nighttime and daytime activity spaces [18,[48][49][50][51][52][53][54]. Further research with improved experimental design will help to distinguish between multiple behavioral states such as resting, searching, foraging or traveling [55]. ...
Preprint
Full-text available
Background Atlantic tarpon (Megalops atlanticus) are a highly migratory species ranging along continental and insular coastlines of the Atlantic Ocean. Due to their importance to regional recreational and sport fisheries, research has been focused on large-scale movement patterns of reproductively active adults in areas where they are of high economic value. As a consequence, geographically restricted focus on adults has left significant gaps in our understanding of tarpon biology and their movements, especially for juveniles in remote locations where they are common. Our study focused on small-scale patterns of movement and habitat use of juvenile and subadult tarpon using acoustic telemetry in a small bay in St. Thomas, U. S. Virgin Islands. Results Four juvenile tarpon (80 – 95 cm FL) were tracked from September 2015 to February 2018, while an additional eight juveniles (61 – 94 cm FL) left the study area shortly after tagging and were not included in analysis. The four resident tarpon had >78% residency and average activity space of 0.76 km² (range = 0.08-1.17 km²) within Brewers Bay (1.8km²). Their vertical distribution was <18 m depth with occasional movements to deeper water. Activity was greater during day compared to night, with peaks during crepuscular periods. During the day tarpon used different parts of the bay with consistent overlap around the St. Thomas airport runway and at night tarpon typically remained in a small shallow lagoon. However, when temperatures in the lagoon exceeded 30 °C, tarpon moved to cooler, deeper waters outside the lagoon. Conclusion Our results, although limited to only four resident fish, provides new baseline data on the movement ecology of juvenile Atlantic tarpon. We showed that juvenile tarpon had high residency within a small bay and relatively stable non-overlapping daytime home ranges, except when seasonally abundant food sources were present. Fine-scale acoustic tracking for over a year showed the effects of extreme environmental conditions on tarpon movement and habitat use. These observations highlight the need for more extensive studies of juvenile and subadult tarpon across a broader range of their distribution, and compare the similarities and differences in behavior among various size classes of individuals from small juveniles to reproductively mature adults.
... Reef fish display highly complex diel patterns in movement, with some being more active during different periods of the day (Hitt et al. 2011). Environmental factors, including predation threat and optimal foraging opportunity, likely play a dominant role in structuring diel behaviors (Rooker et al. 2018). ...
Article
Full-text available
As opposed to passive, broad-scale acoustic telemetry arrays, acoustic positioning systems generate high-resolution animal locations that provide information on long-term, fine-scale movement patterns and habitat preferences. However , limited comparisons have been made between more common broad-scale acoustic data and fine-scale positioning data and it is unknown whether differences exist in ecological inferences gained or lost between using either array configuration over the other. Broad-scale movement and habitat use information was collected for eight Yellowtail Snapper Ocyurus chrysurus tagged within an array of 78 stationary acoustic receivers deployed in Buck Island Reef National Monument, a marine protected area located northeast of St. Croix, U.S. Virgin Islands. An additional 25 receivers were nested within the larger array as a VEMCO Positioning System and were used to assess fine-scale habitat use for five of the eight tagged fish. Broad-scale results inferred from network analysis revealed that all individuals had core use receivers along the shallow shelf break situated west of Buck Island, preferring an area that was coarsely characterized by sand and seagrass benthic habitats. Fine-scale results using Euclidean distance analysis (EDA) suggested fish positions occurred randomly or independent of benthic habitat type. Further exploration of positioning data suggested that there were two contingents or groups of fish displaying unique movement patterns within the fine-scale positioning array. Individuality in space and habitat use was thus masked when using an EDA approach at the study population level, as it was also missed during broad-scale analyses. Discrepancies between broad-and fine-scale habitat inferences suggest that positioning systems are necessary for interpreting habitat use in complex coral reef ecosystems. Nested positioning systems appear to add substantial information that is not obtainable using broad-scale data alone, and caution is necessary in inferring habitat use when only coarse-scale location data are available.
... Each 500-m radius site included nine transect locations selected randomly from Schärer-Umpierre's (2009) sampling points, for a total of 81 transect locations. Sampling sites were separated by at least one kilometer to maintain independence according to published home range sizes of common Caribbean reef fish [56][57][58]. In the interest of providing greater temporal resolution to the statistical design, data from 108 belt and roving transects conducted in 2010 were assigned to spatially corresponding sites and incorporated in analyses (Table 1; Fig 1b). ...
Article
Full-text available
Geographic isolation is an important yet underappreciated factor affecting marine reserve performance. Isolation, in combination with other factors, may preclude recruit subsidies, thus slowing recovery when base populations are small and causing a mismatch between performance and stakeholder expectations. Mona Island is a small, oceanic island located within a partial biogeographic barrier-44 km from the Puerto Rico shelf. We investigated if Mona Island's no-take zone (MNTZ), the largest in the U.S. Caribbean, was successful in increasing mean size and density of a suite of snapper and grouper species 14 years after designation. The La Parguera Natural Reserve (LPNR) was chosen for evaluation of temporal trends at a fished location. Despite indications of fishing within the no-take area, a reserve effect at Mona Island was evidenced from increasing mean sizes and densities of some taxa and mean total density 36% greater relative to 2005. However, the largest predatory species remained rare at Mona, preventing meaningful analysis of population trends. In the LPNR, most commercial species (e.g., Lutjanus synagris, Lutjanus apodus, Lutjanus mahogoni) did not change significantly in biomass or abundance, but some (Ocyurus chry-surus, Lachnolaimus maximus), increased in abundance owing to strong recent recruitment. This study documents slow recovery in the MNTZ that is limited to smaller sized species, highlighting both the need for better compliance and the substantial recovery time required by commercially valuable, coral reef fishes in isolated marine reserves.
Article
Full-text available
Soundscape ecology is an emerging field in both terrestrial and aquatic ecosystems, and provides a powerful approach for assessing habitat quality and the ecological response of sound-producing species to natural and anthropogenic perturbations. Little is known of how underwater soundscapes respond during and after severe episodic disturbances, such as hurricanes. This study addresses the impacts of Hurricane Irma on the coral reef soundscape at two spur-and-groove fore-reef sites within the Florida Keys USA, using passive acoustic data collected before and during the storm at Western Dry Rocks (WDR) and before, during and after the storm at Eastern Sambo (ESB). As the storm passed, the cumulative acoustic exposure near the seabed at these sites was comparable to a small vessel operating continuously overhead for 1–2 weeks. Before the storm, sound pressure levels (SPLs) showed a distinct pattern of low frequency diel variation and increased high frequency sound during crepuscular periods. The low frequency band was partitioned in two groups representative of soniferous reef fish, whereas the high frequency band represented snapping shrimp sound production. Daily daytime patterns in low-frequency sound production largely persisted in the weeks following the hurricane. Crepuscular sound production by snapping shrimp was maintained post-hurricane with only a small shift (~1.5dB) in the level of daytime vs nighttime sound production for this high frequency band. This study suggests that on short time scales, temporal patterns in the coral reef soundscape were relatively resilient to acoustic energy exposure during the storm, as well as changes in the benthic habitat and environmental conditions resulting from hurricane damage.
Preprint
Full-text available
Background Atlantic tarpon (Megalops atlanticus) are highly migratory species ranging along continental and insular coastlines of the Atlantic Ocean. Despite broad geographic distribution and importance as recreational fisheries, little is known about space-use patterns of tarpon within the Eastern Caribbean. Acoustic telemetry was used to track tarpon (n=14, 61- 95cm-FL) from September 2015 to February 2018 in St. Thomas, U.S. Virgin Islands to understand horizontal and vertical movements during diel, crepuscular and seasonal periods and under different environmental conditions. Results Eight tarpon were transient while four had >80% residency and average activity space of 0.76 km² (range = 0.075-1.174 km²) within a small (~1.8km²) bay. Tarpon occurred in <18 m depth with occasional movements to deeper water, including during hurricanes. Activity was greater during day compared to night, with peaks during crepuscular periods. During the day tarpon primarily utilized the waters along the St. Thomas airport and at night tarpon typically remained in a small shallow lagoon. However, when temperatures in the lagoon exceeded 30 °C, tarpon moved to cooler, deeper waters outside the lagoon. Conclusion This study showed distinct and mostly non-overlapping home ranges except when seasonally abundant food sources were present and provided a unique perspective on the effects of extreme environmental conditions on tarpon movement and habitat use. These metrics are useful for management of tarpon, particularly under changing climatic conditions.
Article
Full-text available
A total of 374 striped parrotfish (Scarus croicensis) were tagged from the reefs surroundihg Isla Pico Feo on the Caribbean coast of Panama. Many of these fish were followed individually in the field for up to 3 months. Three different behavioral categories were recognized: stationary, territorial, and foraging. Fish tend to aggregate in foraging groups in a particular pattern relative to reef structure and have a predictable set of associated species. Transfer experiments showed that striped parrotfish have strong ties to a home reef. Striped parrotfish migrate diurnally from shallow-water feeding areas to deeper nocturnal resting areas along constant pathways. Direct counts of fish on migration pathways provided information on the structure and size of the striped parrotfish population at Pico Feo. The numbers of male striped parrotfish may regulate the phenomenon of sex reversal in the scarids.
Article
Full-text available
Manual acoustic telemetry techniques were used to study spatial and temporal patterns of movement of juvenile lemon sharks. Ultrasonic transmitters were implanted into the coelom of 38 sharks, yielding trackings totaling 2281 telemetry fixes. Activity space varied from 0.23 km2 to 1.26 km2 and was positively correlated with shark size. Three indices of site attachment demonstrated that juvenile lemon sharks establish a home range. An index of site defense and field observations indicated that no territoriality was observed against conspecifics.
Book
In the last two decades it has become increasingly clear that the spatial dimension is a critically important aspect of ecological dynamics. Ecologists are currently investing an enormous amount of effort in quantifying movement patterns of organisms. Connecting these data to general issues in metapopulation biology and landscape ecology, as well as to applied questions in conservation and natural resource management, however, has proved to be a non-trivial task. This book presents a systematic exposition of quantitative methods for analyzing and modeling movements of organisms in the field. Quantitative Analysis of Movement is intended for graduate students and researchers interested in spatial ecology, including applications to conservation, pest control, and fisheries. Models are a key ingredient in the analytical approaches developed in the book; however, the primary focus is not on mathematical methods, but on connections between models and data. The methodological approaches discussed in the book will be useful to ecologists working with all taxonomic groups. Case studies have been selected from a wide variety of organisms, including plants (seed dispersal, spatial spread of clonal plants), insects, and vertebrates (primarily, fish, birds, and mammals).
Chapter
In the previous chapter we presented the idea of a multi-layer, multi-scale, spatially referenced data-cube as the foundation for monitoring and for implementing flexible modeling of ecological pattern—process relationships in particulate, in context and to integrate these across large spatial extents at the grain of the strongest linkage between response and driving variables. This approach is powerful for developing information about the conditions of multiple ecological attributes continuously across the analysis area. However, there are a number of ecological questions that involve processes that are not functions of ecological conditions at point locations alone. Many of these involve spatial processes and mobile agents, such as the spread of disturbances, dispersal of propagules, and the movement of mobile animals. The focus of this chapter is on animal movement data.