Thesis presentation final

The
movement
of
white
grunts

(Haemulon
plumierii)
rela5ve
to

habitat
and
boundaries
at
various

spa5al
and
temporal
scales

Stephanie
J.
Williams

Department
of
Marine
Sciences

University
of
Puerto
Rico,
Mayagüez
Campus

Outline:

 Introduc5on:
Fish
Movement
vs.
Habitat
Boundaries

 Objec5ves

 Acous5c
Monitoring

 Methods,
Results,
Discussion

 Visual
surveys
/
Video
recordings

 Methods,
Results,
Discussion

 Applica5on
of
Acous5c
telemetry
with
Viewshed®

 Methods,
Results,
Discussion

 Overall
Conclusions

 Acknowledgements

Introduc5on:

Why
study
ﬁsh
and
habitat?

FISH
DISTRUBTION,

HABITAT
DISTRUBTION,

ABUNDANCE,
ABUNDANCE,

MOVEMENT
ARRANGEMENT

ECOSYSTEM-‐BASED

MANAGEMENT

DEFINE
NURSERY
AREAS,
EFH
&
TROPHIC
FLOWS

DESIGN
PRINCIPLES
FOR
MPAS
&

MARINE
SPATIAL
PLANNING

(Botsford et al. 2003, Barnes and Thomas 2005, Dahlgren et al. 2006)

Theore5cal
Framework:

Habitat
Arrangement
&
Boundaries

Open Sand Seagrass Gorgonians Coral Reef

Aﬀect
Probability,
Direc5on
&
Timing
of
Movement

(Appeldoorn et al. 2009)
_____________________________________________________

 Weins
(1992):
Percep5on
of
Boundary
Permeability:

1.
Contrast:
Diﬀerences
in
Benthic
Topography
Forma5ons

-‐
deter
movement
(high);
allow
movement
(low)

-‐
presence
of
predators
enhances
contrast
(ontogene5c
mig.
at

larger
body
size;
reduce
probability
of
preda5on)
(Werner & Gilliam 1984)

2.
Thickness:

Distance
to
Cross
for
Next
Suitable
Habitat

-‐
ability
to
detect
suitable
habitat
at
a
distance;
prior

experience
and
naviga5onal
skills
(Bardach 1958)

Why
grunts?

  Well-documented
  Commercially & Ecologically Important (transfer nutrients)
( Appeldoorn & Lindeman 1985, Meyer & Schultz 1985, Clark et al. 2005)

-‐
Rest
During
Day
on
Coral
Reefs
-‐
Forage
in
Seagrass
Beds
&
Sand
Flats

-‐
Res5ng
Schools
-‐
Solitary

-‐
Dawn
re-‐aggrega5on
-‐
Dusk
Migra5on

_________________________________________________
Predictable Time, Predictable Route
-  Navigation: Vision, Map-Sense, Compass Headings
-  Degree & Timing: Size-Dependent
-  Partition Feeding Area Efficiently/Reduce Predation Risk?
(McFarland et al. 1979, Ogden & Quinn 1989, Bouwmeester 2005, Pittman et al. 2007)

Grunts:
Movement
vs.
Habitat

WHAT
WE
CAN
EXPECT:

-‐
Good
naviga5onal
skills
&
broad
knowledge
of
seascape

-‐ 
Reef-‐seagrass
(low)
vs.
Reef-‐open
sand
(high
&
thick)

(Tulevech & Recksiek 1994, Appeldoorn et al. 2009)
-‐
Reef-‐sand
interface
high
un5l
night
(low)

(Helfman et al. 1982, Rooker & Dennis 1991)

-‐ 
Boundary
Permeability
Dependent
on:

-‐
Lifestage

-‐
Time-‐of-‐Day

-‐
Loca5on

-‐
Visibility

-‐
Preda5on

-‐
Presence
of
Con-‐Speciﬁc/
Similar-‐Sized
Inter-‐Speciﬁc
Fish

WHAT
IS
MISSING:

-‐
Extensive
long-‐term
research
linking
transi5onal
lifestages

-‐ 
Understanding
behaviors
at
boundaries,
movements
across

boundaries
and
limits
at
various
spa5al
and
temporal
scales

-‐ 
Understanding
limita5ons
of
techniques
for
accurate

assessment
and
mapping

N
Puerto Rico
Objec5ves

Majimo Ridge
Caracoles
Corral

Romero

Turrumote

-‐
Inves5gate
movements
of
subadult
and
adult
white
grunts
at
various
scales

(Habitat,
Boundaries)

Image source: PR (bergoiata.org); La Parguera (IKONOS 2006)

Objec5ves

Acous5c
Telemetry:


Test
boundary
responses
through
displacement

  Iden5fy
short-‐
and
long-‐term
movement
paeerns

Visual
Surveys/Video
Recording:


Examine
distribu5on,
distances
moved,
an5-‐predator

behaviors
and
rela5on
to
habitat
boundaries
at
Dawn,

Midday
and
Dusk

Acous5c
Telemetry
vs.
Viewshed®:


Examine
spa5al
paeerns
of
recep5on
range
rela5ve
to

geomorphology

vs.
line-‐of-‐sight
theory

Acous5c
Monitoring:
Study
Sites

EXPERIMENTAL DESIGN
 Displacement studies

-‐
Use
Homing
to
test

Boundary
Response

 Short-term movements

-‐
Determine
Home
Range

  Long-term movements

-‐
ID
shi9s
in
home
range

w/
longer
con=nuous
gaps

-‐ 
19
Passive
acous5c
receivers

-‐ 
76
Receiver
Loca5ons:

-‐
Reef
crest

-‐
Mid-‐slope

-‐
Reef-‐sand
Interface

-‐
Open
Sand

-‐
21
Trap
Loca5ons

Source: CCMA/ Biogeography Team
(http://ccma.nos.noaa.gov/products/
biogeography/lidar_pr)

Acous5c
Monitoring:
Equipment

-‐ 
Transmieer:
V7
(7x20mm,
0.75g
in
SW;
69kHz)

Configura5ons
of
36
tagged
fish:

1.
7
fish
-‐

Base
life:
52
days

2.
10
fish
-‐
Base
life:
100
days

3.
19
fish
-‐
Base
life:
220
days

-‐ 
VR2
&
VR2W
Receivers:

-‐
Records
Transmieer
ID
Code,
Time
&
Date

-‐
Nominal
range:
~250m
radius

-‐ 
Boat-‐based
VH-‐110
Direc5onal
Hydrophone

-‐
Records
ID
code
on
VR60
PC
Solware

-‐
VUE
Solware:
12
Uploads
(08/16/08
–
11/20/09)

Data
Analysis

-‐  Time-‐series
results
organized
into:

1.

Maps
to
show
spa5al
scale
of
movement

2.
Graphs
to
summarize
temporal
paeerns

_____________________________________________________
-‐  Correla5ons
within
&
among
days
to
ID
trends

at
various
scales
&
presence/absence
paeerns

(Autocorrela5on
Func5on/Periodograms(Enright
1965,
Box
&
Jenkins
1970))

_____________________________________________________
-‐  Habitat
zone
u5liza5on
assessed
to
ID
spa5al
trends

(Forereef,
Backreef,
Forereef-‐Backreef
Transi5on,
Channel)

Results:
Fish
Displacements

-‐ 
5
adults

-   distance
between
reefs

w/
open
sand
&
w/
reef/gorg.
(200m-‐730m)

-‐ 
No
white
grunts
at
release
sites

-‐ 
Boat-‐Based
Hydrophone:
homeward-‐
bound
direc5on

-‐ 
Mo5va5on
to
return
by
day

-‐
Fish
50350
only
successful
return:
to
WBT
by
night
(109
days)

-  7: 4 adults,
3 subadults
Results:
Fish
Displacements

-  Greater
Challenges:
1. Increasing
Distance
870m-2.8km
2. More areas
w/ other
white grunts
3. Only from
WBT
4. Replicates
-  Records:
7- 54 days
- All adults
returned/ after
days by night
-  Subadults:
no return- left
release site
after ~1wk

Results:
Short-‐term
Movements

Max. Dist.: ~360m Max. Dist.:
~225m
-  14 adults
(50350, 60609,14)

-  W. ends of
Turrumote (n=6)
& Corral (n=5)
& E. Forereef
Corral (n=3)

E. Forereef Corral

-  Records:
12/200-215/218 days
Max. Dist.:
(Short time intervals ~100m
of presence/absence)

Short-‐term
Results:
Turrumote

50345
50350

-  Predominant use of backreef at
night & forereef during day
-  Changing patterns of several
weeks for use of backreef diurnally
- Individual variability
- Faster to Forereef: ~30min
- Slower Return: ~1hr

Short-‐term
Results:
W.
Corral

-  All-day use of transition on slope/ weekly p/a
- Shift: decreasing to increasing at backreef all day

50364
-  Nocturnal use on slope
- Shift: decreasing to
increasing at backreef all day;
50368 shallow backreef at night only

Short-‐term
Results:
E.
Corral

-  All-day use of reef-
sand interface w/
minimal to no
detections between
dusk & dawn

________________________________________________
Turrumote
&
Corral:

-  Shifting movements and activity at multiple receivers (relocation of receivers)
-  All movements occurred on small portion of available reef (up to ~300m in range)
-  Twilight Movement: Facilitate Presence/Absence Patterns & Frequency of
Detections

Results:
Long-‐term
Movements

-  3 adults
-  Caracoles Forereef (n=2) and Májimo Ridge (n=1)
-  No large-scale, offshore, reef-boundary-crossing
to other emergent reefs occurred
-  Records: 16/230 – 117/231 days
-  Longer temporal shift in specific locations on reef
crest and forereef-sand interface
-  Geomorphology similar at both locations
(Reef crest: 3-5m; Reef-sand: 8-12m)
- Connectivity - large patch reefs off emergent reef
structure- potentially more permeable than Turr/
Corr
-  Scattered presence of white grunts at both just as
E. Forereef Corral
Max. Dist.: ~150m

Results:
Long-‐term
Movements

-  Greater variations in absence at a single receiver
-  Detecting fish in new/nearby locations
Caracoles -  Shifts in habitat use at varying degrees over time

50354
-  3-month
intervals
-  Relocation

50361
once
receiver
moved
______________________________________________________________________
Májimo Ridge
50359

-  Monthly
intervals
-  Relocation
once
receiver
moved

Data
Analysis:
Periodicity
Among
Days

- Total of 17 Individuals w/ Robust Time Series (>1wk)
-  Autocorrelation Technique (99% C.I.; p<0.0001):
- Significant Lags (Presence/Absence):
- ~90% of 17 individuals had a lag of 1 day

- Short-term Patterns: 1-7 days - Long-term Patterns: up to 29 days

-  Up to Lag 7 (weekly pattern); -  Up to Lag 29 (monthly pattern)
Fish 50364 @ W. Corral Fish 50354 @ Caracoles

Data
Analysis:
Periodicity
Within
24
hours

-  Total of 34 Time Series Correlated (1,122 possible comb.)
-  In Natural Home Range / Upon Settlement after Displacement
-  22 Significant Correlations (17 +; 5 -; (r > +/- 0.926; p<0.0001)
- Of 17 positive correlations,
13: significant nocturnal presence
-  Diel trends for reef zone utilization:
# Time
Category Series Key
FA 5
FD 5 A= All day and night
FN 4 D= Diurnal
- Backreefs: All day or nocturnal BA 7 N= Nocturnal
BD 0 F= Forereef
(no diurnal presence alone) B= Backreef
BN 6
TA 1 T= Transition
TD 2 C= Channel
TN 3
CD 1

Acous5c
Monitoring:
Discussion

•  Boundary
Permeability:
nocturnal
use/returns

-‐
Dependent
on
assessing
preda5on
risk?
(Werner & Gilliam 1984)

-‐
Primary
concern
for
juveniles
(schooling
in
day,
twilight
migra5ons
in
train
of

ind.,
solitary
feeding)?
(McFarland et al. 1979)

-‐
Adults
recorded
at
same
5me
at
W.
Corral
and
Turrumote:
pairs,
groups?

•  Returns
aler
Displacement

-‐
Dependent
on
shortest
route
/
magnitude
of
obstacles?

-‐
Length
of
5me
to
ﬁnd
shortest
path
shows
learning

(speed
to
return
second
5me
(60609))
Enrique

-‐
Previous
observa5ons:
adult
displaced
from
Enrique
to

Media
Luna
and
did
not
return
(short
baeery
life
to

1km

conﬁrm
whether
stayed
or
not)
(Tulevech & Recksiek 1994)

Media Luna

Acous5c
Monitoring:
Discussion

•  Mul5ple
Receivers:
How
ﬁsh
use
area
inhabited

-‐
Small
por5on
(<300m)
of
poten5al
available
habitat

-‐
Autocorrela5on
results:
shiling
ac5vity
last
~1wk

-‐
Detec5ons
at
nearby
receivers
(using
subparts
of
total
area)

•  Shils
in
habitat
use
at
varying
degrees
&
5me
frames

-‐
Varia5ons
in
frequency
of
detec5ons
at
single
receivers
&
new
loc.
upon

moving
receivers

-‐
Autocorrela5on
results:
shiling
ac5vity
last
~1month;
periodic
returns
–

previous
subareas

Acous5c
Monitoring:
Discussion

•  Home
Range:
“area
typically
used
over
some
speciﬁed

period
of
5me,
ontogene5c
phase
or
ac5vity”

(Pieman
&
McAlpine
2001)

-‐
If
cycling
behavior
through
subareas,
only
long-‐term
records:
full
range
of

movement

•  Technology
Limita5ons:

-‐
Range/Posi5on
vs.
Movement

-‐
Detec5on
Capabili5es

(Twilight)
or

(Midday)

Visual
Surveys/Video
Recordings



Examine
distribu5on,
distances
moved,
an5-‐predator
behaviors
and

rela5on
to
habitat
boundaries
at
Dawn,
Midday
and
Dusk

Visual
Surveys/Video
Recordings:

Study
Sites

-‐
9
sites
selected
due
to
presence
of
white
grunts

-‐
18
Visual
Surveys:

3
Dawn
(~06:00),
9
Midday
(~12:00),
6
Dusk
(~18:00)

-‐
Midday
sites
first-‐
ID
general
abundances

-‐
Dawn/Dusk
only
at
sites
w/
suitable
#s
found

Transects:
(<250m)

-‐
GPS
device/diver;
tracked
waypt.
every
10
sec

-‐
Visual
surveys
supplemented
with:

Low-‐light
Underwater
Video
Recorder

(M. Schärer/D. Mann)

-‐
4
sites
(Corral
and
Turrumote)

-‐
Reveal
off-‐reef
movement/direc5on
in
most

natural
setng
(4-‐10m
off
reef)

M. Schärer

Visual
Surveys:
Methodology

I.
Assess
ver5cal
posi5on
on
reef:

-‐
Record
frequency
of
observa5ons
on:

1.
Reef
Crest
(4-‐8m)

2.
Top
Slope
(8-‐9m)

3.

Mid
Slope
(9-‐11m)

4.

Reef-‐Sand
Interface
(11-‐16m)

-‐
Habitat
boundaries
classiﬁed
in
terms
of
low
to
high
contrast

II.
Record
distances
moved:

1.
Horizontally
across
seascape
(sand/structure)

2.
Ver5cally
oﬀ
sand/structure

Visual
Surveys:
Methodology

III.
Social
grouping:

1.
Forma5on
of
groups
as
an5-‐preda5on
strategy

2.
Learning

(Helfman et al. 1982, Bouwmeester 2005)

-‐
Solitary,
Pairs,
Agg.
3+,
congenerics,
acanthurids,
goavishes,

parrovishes,
mix
species

IV.
Boundary
Response
Behaviors:

-‐
Behaviors
when
solitary
or
in
groups
as
an5-‐preda5on
strategy

(Helfman et al. 1982, Rooker & Dennis 2001)
-‐
Hiding,
pale/countershading
colora5on,
convene
&
disperse,
move

one
agg
to
another

_____________________________________________________________
-‐
Resemblance/Bray-‐Cur5s;
SIMPER
Tests:

-‐
Lifestage
Similari5es

-‐
Non-‐parametric
K-‐W
ANOVA
on
Ranks
Tests:

-‐
Diﬀerences
in
occupancy
of
reef
zone;
lifestage-‐,
5me-‐of-‐day-‐,
site-‐

dependent

-‐
Post-‐test
Pairwise
Mul5ple
Comparison:

ID
poten5al
drivers

Results:
Distribu5on
on
Reef

-‐ 
Observed
more
at
Midday;
scaeered
&

SITE STAGE DAWN MIDDAY DUSK

solitary
W Backreef SA 4 5 3
-‐ 
Adults
more
abundant
at
Corral/Turrumote
Turrumote A 7 20 5

-‐ 
WchanR/WRom:
no
adults;
1
SA
at
each
W Backreef SA 3 2 3
-‐ 
Twilight:
discrete
loca5ons
on
reef
margins
Corral A 6 20 17

adj.
patch
reefs,
f-‐b
transi5on
zones

Results:

SUBADULTS ADULTS
DAWN
Loca5on
on
Reef

-‐ 
Subadults/Adults:
Mid
Slope
to

Reef-‐Sand
Int.

-‐ 
Signiﬁcant
Diﬀerences
in

Loca5on
MIDDAY

(K-‐W
ANOVA
on
Ranks;
p<0.001)

-‐ 
Reef-‐Sand
=
Midslope>Top

Slope>Reef
Crest

(Tukey
Test;
p<0.05)

-‐ 
Subadults
con5nually
more

DUSK

present
on
Top
Slope
&
Reef

Crest;
No
adults
observed
on

Reef
Crest
at
Dawn/Midday,
1
at

Dusk

Results:
Loca5on
on
Reef

-‐ 
SIMPER
Results
between
lifestages:

-‐
Dawn:
Highest
(64.5%)

-‐ 
Midday:
Lowest
(27.4%)

(Subadults
encompass
whole
reef,
Adults
mainly
Mid
Slope
to
Reef-‐Sand
Int.)

-‐
Kruskal-‐Wallis
One-‐Way
ANOVA
on
Ranks:

-‐ 
Lifestage-‐Dependent:

Reef
Crest
(Driven
by
Subadults)

-‐
Site-‐Dependent:
Mid
Slope
,
Reef-‐Sand
Int.(Higher
rugosity/Ledge
Sys:
WBC/WBT)

Results:

Distances
Moved

-‐
Maximum
Horizontal/Structure:
Midday
(~45m)

-‐
Maximum
Ver5cal/Structure:
Dusk
(~1m)

-‐ 
Differences
between
lifestages
Midday:

-‐ 
Greater
difference
in
max.
off
reef
movement:
2
inshore
sites

(Majimo:
SA:
~14m
A:
1m;
Caracoles:
SA:
~6m
A:
1m)

-‐ 
Greater
difference
in
horizontal
movement
on
structure

(WB
Corral:
SA:
44m,
A:
~8m)

*
Subadult
movement
further

-‐ 
Differences
at
Twilight:

-‐ 
Twilight
movements
off
reef:
more

site-‐dependent
than
midday

(Turrumote
at
dawn
(9m),
Majimo
at
Dusk
(12m))

-‐ 
Dusk:
Adults
moved
greater
distances
on
structure

at
Corral
(25m)
vs.
Subadults
at
Caracoles
(25m)

Results:
Distances
Moved

-‐ 
SIMPER
Results
between
lifestages:

-‐
Dawn:
highest
(for
both
horizontal
and
ver5cal
distances)

-‐
Midday:
lowest
(Subadults
driving
variability,
generally
moved
more)

HORIZONTAL DISTANCES VERTICAL DISTANCES

-‐
No
signiﬁcant
diﬀerences
(K-‐W
Anova
on
Ranks):
low
sample
size?

-‐
Video
footage:
Movement
direc5on
inconsistent
among
sites

-‐
E.
Forereef
Corral:
Both
Direc5ons

-‐
W.
Corral:
To
Forereef
at
Dawn/
To
Backreef
at
Dusk

-‐
W.
Turrumote:
To
Backreef
at
Dawn/
Both
at
Dusk

Results:

SOCIAL
GROUPING:

-‐ 
Dawn/Midday:
Similar
counts
when
solitary,
in
pairs,
in
agg
3+

-‐ 
No
great
diﬀerence
between
midday
&
twilight
(except
for
increases
in

numbers
midday)

-‐ 
Twilight:
Similar
for
both
lifestages

-‐ 
Although
low
counts,
adults
observed:
groups
w/
goavish,
parrovish
&

other
Haemulids

Results:

BOUNDARY
RESPONSE
BEHAVIORS:

-‐ 
Both
lifestages
generally
similar

-‐ 
Diﬀerences
between
5me
periods:

-‐
Midday
&
Dusk:
Change
to
Countershading

-‐
Midday:
Convene/Disperse
more
than
twilight

-‐ 
Midday:
Only
subadults
moved
from
one
agg
to
another
agg

Results:
Social
Grouping/

Boundary
Response
Behaviors

-‐ 
SIMPER
Results
between
lifestages:

-‐
SOCIAL
GROUPING:
LOW
Similari5es
throughout
day

-‐
BOUNDARY
RESPONSE
BEHAVIORS:
LOW
Similari5es

(Dawn:
slightly
higher)

-‐
Infer
Lifestage
Diﬀerences

GROUPING

BOUNDARY

BEHAVIORS
RESPONE
SOCIAL

-‐
Kruskal-‐Wallis
One-‐Way
ANOVA
on
Ranks:

-‐ 
Lifestage-‐Dependent:

With
Parrovishes
(Driven
by
Adults)

-‐
Time-‐of-‐Day-‐Dependent:
Hiding
in
Structure
(Midday)
/Pale
Colora5on
(Dawn)

-‐
Site-‐Dependent:
Aggrega5ons
3+
(WBC),
With
Acanthurids
(WBT),
Pale
Colora5on

Visual
Surveys/Video
Recordings:

Discussion

 Significant
differences
in
observed
behaviors
(interpreted
as
reducing
preda5on

threat)
can
occur
as
func5on
of
lifestage,
loca5on
and
5me
of
day



Adults
less
likely
to
move
off
reef
at
night;
reducing
vulnerability
to
stay
on
or
near
reef

(greater
food
resources)
vs.
subadults
-‐
s5ll
may
reflect
juvenile
behaviors
to
avoid

preda5on
and
leave
reef
at
night

(Appeldoorn et al. 1997, 2009, Tulevech & Recksiek 1994)
 

-‐
Subadults
&
Adults:
Mid-‐Slope
to
Reef-‐Sand
Interface
(high
contrast)

-‐
Subadults:
remain
in
denser
gorg.
mid-‐
to
top-‐slope
(low
contrast)

 Highest
Similari5es
between
Lifestages:
Twilight
(Dawn)
-‐preda5on
risk
greater?


Similari5es:
Visual
Surveys
vs.
Video
Footage

-‐
Poten5al
pre-‐migratory
behaviors

-‐
Use
of
sand
channels
on
slope,
within
reef
structure
&
Reef-‐Sand
Interface
as
corridors

-‐
Communica5on
through
grun5ng
sounds
at
Twilight

  Footage
supports
idea:
in
absence
of
predators/divers,
fishes
increase
range
of
movement

  Both
techniques
will
aid
in
beeer
understanding
of
behavioral
movement
paeerns/

lifestage
differences

Visual
Surveys/Video
Recordings:

Discussion

Interpreta5on
at
larger
scale

VISUAL
SURVEYS

ACOUSTIC
MONITORING

-  Visual surveys at reefs w/ minimal -  Absence of detections at
connectivity (Corral/Turrumote) show receivers may not imply
do not move much off main reef boundary-crossing
-  Distances moved horiz. on structure: - Not departing but nearby in
Midday (Subadults:16.4m; Adults:11.7m) 250-m range
Twilight (Subadults:10.5m; Adults:9.3m)
-  Distances moved horizontally off -  Movements on/off structure may
structure: Twilight (both: ~3m) cause variations at different
times of day

Visual
Surveys/Video
Recordings:

Discussion

Interpreta5on
at
larger
scale

VISUAL
SURVEYS

ACOUSTIC
MONITORING

- Solitary subadult moved after 5 -  Adults moved after several
attempts - patch reef/main reef (Majimo) nights of attempts to cross
Corral to Turr
- Greater subadult movement at home -  Displaced subadults ~1km
reefs w/ greater connectivity; off-reef across sand channel (Corral/
movement Turr) no return
- Adults with smaller range of movement -  Displaced adults did return

* Range of movement not the only factor controlling ability to return:
navigational experience?/ predation threat?

Applica5on
of
Acous5c
Telemetry
vs.
Viewshed®



Examine
spa5al
paeerns
of
recep5on
range
rela5ve
to

geomorphology

vs.
line-‐of-‐sight
theory

Applica5on
of
Acous5c
Telemetry
vs.
Viewshed®:

Study
Area

-‐ 
11
selected
points
out
of
76
total

receiver
loca5ons

-‐ 
Poten5al
range
limits
assumed
to
be

same
for
all
receivers
/
dependent

only
on
site
in
rela5on
to

geomorphology
of
benthos,
habitat

structure
&
composi5on

-‐ 
Selected
points
reﬂected
full

variability:

1.  Open
Sand

2.
Reef-‐Sand
Interface

3. 

On
Slope

4. 

Mixed
Habitat/Reef
Crest

Applica5on
of
Acous5c
Telemetry
vs.
Viewshed®:

Methods

Detection Range Testing
-‐ 
4
transects
at
each
point:
within
250-‐m
radius

-‐
Receiver
placements
(1.5m
oﬀ
boeom);

Excep5ons:
Reef-‐Sand
(2.1m)
&
Open
Sand

(1.5/3m)
to
test
varia5ons
in
range
limits

-‐ 
V7
transmieer:
10-‐second
interval

-‐ 
Waypts.
recorded
every
30
sec.
(up
to
3
detec5ons/waypoint):

imported
to
ArcMap

Boat-based Transects Diving Transects

Applica5on
of
Acous5c
Telemetry
vs.
Viewshed®:

Methods

Viewshed Application
Line-of-sight Theory
-‐ 
Input
data:
Receiver

Loca5on,
Distance

off
boeom
&

Bathymetry
within
250-‐m

radius

-‐ 
Output
data:
Visible
&

Not-‐Visible
Areas

Verifying Viewshed
Evaluate
sources
of
error:

-‐
Combine
modified
benthic
map
&
Viewshed’s
final
map
to
quan5fy
habitat

types
&
ranges
of
degrees
of
slope
to
assess
driving
factors
for
detec5on

limita5ons

(
1.
Areas
where
transmieer
was
detected
when
it
shouldn’t
have
been;

2.
Areas
where
transmieer
was
not
detected
when
it
should
have)

-‐
K-‐W
ANOVA
on
Ranks
tested
variability
among
loca5on
types

Applica5on
of
Acous5c
Telemetry
vs.
Viewshed®:

Results

-‐ 
Viewshed
outputs
coupled
w/
Open Sand (1.5m) Open Sand (3m)

Range-‐tes5ng
at
4
loca5ons

-‐ 
Detec5ons
tend
to
occur

closer
to
receiver

-‐ 
Waypts.
w/
no
detec5ons
tend

to
occur
closer
to
limits

-‐ 
Open
Sand:
placement
at

diﬀerent
depths
-‐
variability

-‐ 
When
receiver
closer

to
boeom,
detec5ons

recorded
further;
with

higher
placement,

detec5ons
recorded

closer
to
receiver

Reef-Sand Interface On Slope Reef Crest

Applica5on
of
Acous5c
Telemetry
vs.
Viewshed®:

Results

-‐ 
Strong
posi5ve
correla5on

between
#
detec5ons
in

r=0.949; p<0.0001

visible
area
vs.
total

detec5ons

-‐ 
On
Slope
&
Mixed
Habitat:

Most
effec5ve
reef
loca5ons

-‐ 
Mixed
Habitat:
Max.
Range

Total
Detec5ons

-‐
Higher
correla5on
in
Open

Sand
vs.
Reef-‐Sand
Interface

(curvature
&
slope
of
main

reef
creates
interference

from
line-‐of-‐sight)

-‐ 
Two
Reef-‐Sand
Pts.
outside
95%
C.I.
show
highest
variability/
ineffec5veness?

-‐ 
Reef-‐Sand
point
with
highest
correla5on
-‐
2.1m
off
boeom,
may
be
more
effec5ve

higher
off
boeom

Applica5on
of
Acous5c
Telemetry
vs.
Viewshed®:

Results

Max Dist Ave Max Dist/
Location Receiver (m) Location (m)
Mixed DIS3 (4799) 0 40 (w/DIS3)
Habitat PT 342 70 60 (w/o DIS3)
-‐ 
Detec5on
distances

VRS3 51

(max=216m)
greatest
for

On Slope VRS2 38 30
VRS4 15

Open
Sand
(s5ll
<250-‐m
radius)
VRS6 37

-‐ 
Next
greatest
(114m)-‐
Reef-‐Sand
Reef-Sand PT 315 73 96 (@ 1.5m)
Interface PT 323 114
-‐ 
Mixed
Habitat
-‐
most
varia5on
VRS5-4802
(1.5m) 100
VRS5-10345
-‐ 
On
Slope
-‐
least
range
(38m)
8(2.1m) 83

-‐ 
Total
Average
Max.
Dist.-‐
72m
Open
Sand
PT 343
(1.5m) 216 114 (@ 1.5m)
PT 343
(1.5m) 147 82 (@ 3m)
PT 343 (3m) 81
PT 343 (3m) 60
PT 344
(1.5m) 82
PT 344
(1.5m) 14
PT 344 (3m) 117
PT 344 (3m) 70
Total average maximum distance
detected 72

Applica5on
of
Acous5c
Telemetry
vs.
Viewshed®:

Results

•  Reliability
of
Viewshed
evaluated
rela5ve
to
error:

-‐
Sta5s5cally
significant
differences
in
%
detec5ons
within
Not-‐Visible
Area
for
all
habitat

types
(K-‐W
ANOVA
on
Ranks;
p<0.05)

-‐
Reef-‐Sand:
Most
Problema5c
(greatest
%
detec5ons
in
Not-‐Visible
Area)

-‐
On
Slope:
Low
errors
for
both

-‐
Mixed
Habitat:
Accurate
(all
detec5ons
in
visible
area);
lowest
detec5on
rate

-‐
More
reliability
w/
Open
Sand
(3m);
trade-‐off
between
detec5on
range
vs.
accuracy

Applica5on
of
Acous5c
Telemetry
vs.
Viewshed®:

Results

-‐ 
Output
for

all
76
loca5ons

-‐ 
Overall
results

(esp.
on
slope):

Oﬀ-‐reef:
Not-‐Visible

-‐ 
Contradicts
prior

ideas
of
detec5on

capabili5es
within

line-‐of
sight

(from

slope,
sand
-‐
visible)

Applica5on
of
Acous5c
Telemetry
vs.
Viewshed®:

Results:
Habitat
in
Visible/Not-‐visible
Areas

Open Reef-Sand
Sand Interface
-‐ 
Dominant
(n=2) (n=51)

Habitat
Types:

Not-‐
Visible:

Unknown/

Sand

Visible:
Linear
Reef

On Mixed
Slope Habitat
(n=9) (n=14)

Applica5on
of
Acous5c
Telemetry
vs.
Viewshed®:

Results:
Slope
in
Visible/Not-‐Visible
Areas

-‐ 
Low
slope:
Greatest
propor5on
for
both

Slope

(Contradicts
prior
ideas:
greater
slope,
less
visibility)
Slope (Degrees) Class
0 - 1.103 1
-‐ 
Ave.
slope:
Not-‐Visible
Area

1.103 - 3.309 2

(excep5on:
Mixed
Habitat-‐
more
heterogeneity)
3.309 - 6.342 3
6.342- 10.203 4
-‐ 
Open
Sand:
Least
Range
in
Visible
(14

deg.
limit);

10.203 - 14.615 5

Class
9
included
in
Not-‐Visible
14.615 - 20.130 6
20.130 - 26.747 7
-‐
Greatest
variance:
Reef-‐Sand
(Not-‐Visible);

26.747 - 35.020 8

On
Slope
(Visible);
curvature
of
reef
driver
for

35.020 - 52.392 9

interference
52.392- 70.315 10

-‐ 
StDev:
On
Slope
-‐
Not-‐visible
areas
more
eﬀec5ve
w/
Viewshed

-‐ 
Slightest
slope
Average Slope Range Variance StDev

diﬀerences

Not- Not- Not- Not-

enough
for
Location Visible Visible Visible Visible Visible Visible Visible Visible

detec5on
Open Sand 3.26 2.19 1--9 1--5 3.28 1.42 1.81 1.19
Reef-Sand Int. 4.15 3.80 1--10 1--10 4.24 4.35 2.06 2.08

limita5ons

On Slope 4.22 4.07 1--9 1--9 4.19 4.81 0.24 2.19
Mixed Habitat 3.83 3.86 1--9 1--9 3.61 4.01 1.90 2.00

Applica5on
of
Acous5c
Telemetry
vs.
Viewshed®:

Discussion

•  Viewshed:
useful
tool
to
ID
areal
detec5on
limits
by
acous5c
receivers

•  Propor5on
detec5ons
high
in
Visible
areas
(despite
varia5on
by
loca5on)

•  Certain
cases
where
line-‐of-‐sight
theory
incorrect:
open
sand
&
low
slope

in
Visible
areas

•  Limita5ons:
proper5es
of
sound
transmission,
behavioral,
ecological
&

social
characteris5cs
of
tagged
species

•  Rugosity,
habitat
type,
boeom
layer
(wave
surge,
suspended
sediment):

create
interference
not
ID’d
by
Viewshed

_____________________________________________________
•  Adjustments
to
bathymetry
layer
to
include
rugosity
(smaller
resolu5on)

may
facilitate
interpreta5on
of
residency/movement
paeerns
oﬀ
reef

•  Future
tracking
studies:
closer
arrays
(corridor
of
overlapped
ranges:
Reef

Crest
(~40m)
to
Slope
(~30m)
to
Interface
(~96m)
to
Open
Sand
(~82m
@
3m)

Overall
Conclusions

Acous5c
Telemetry:


Characterize
movements
&
shiling
paeerns
over
5me
&

responses
to
poten5al
boundaries
at
various
scales

  Displacement:
boundary
permeability
depends
on
body
size
&

learning

  Boundary-‐crossing:
larger
body
size,
short
distance,
connec5vity,

twilight/nocturnal
periods

  Short-‐term:
low
light
levels
at
twilight
reduce
contrast,
ini5ate

movement

  Long-‐term:
environmental
stressors
may
ini5ate
larger
shils

  Both
lifestages
spend
days,
weeks,
months
near
or
away
from

discrete
loca5ons
limited
to
~300m
range

  Backreef
areas:
used
all
day
or
only
at
night
(not
diurnal
only)

  Primary
pathway
at
forereef-‐backreef
transi5on
areas:
reef-‐
slope-‐sand
interface

Overall
Conclusions

Visual
Surveys
/
Video
Recordings:


Significant
rela5onship
among
habitat
structure
&
distribu5on
&
daily

distribu5on,
movement
&
behaviors
of
white
grunts

  Subadult
ac5vity/range
of
movement
greater;
occupy
similar
space

  Adults
remain
on
reef
despite
higher
risk;
Subadults
s5ll
reflect
need
to
move

off
reef
to
avoid
preda5on

  Recommenda5ons:
show
results
to
compare
w/
mid-‐
to
late-‐juvs

  Cross-‐boundary
moves
facilitated
by
habitat
connec5vity
w/
minimal

thickness/contrast,
twilight,
grouping
w/
similar-‐sized
fish

  Barriers/Corridors:
slope
changes,
transi5on
zone,
abundance
of
sol
coral

cover,
ledge
systems

  Obs.
Behaviors:
lifestage-‐dependent
(adults
w/
dissimilar
sp.,
subadults
on

reef
crest),
5me-‐of-‐day-‐dependent
(hiding,
pale),
site-‐dependent
(social

structure
of
agg
on
slope)

  Environmental
cues:
light
changes
during
twilight

  Voluntary
habitat
changes:
decrease
w/
inc.
body
size,
inc.
w/presence
of

conspecifics/congenerics,
proximity
adj.
structure

Overall
Conclusions

Acous5c
Telemetry
vs.
Viewshed
®:


Spa5al
Analyst’s
Viewshed:
effec5ve
planning
tool
to
assist
efficient

monitoring;
ID
smaller-‐scale
habitat
use/home
range
boundaries

  Limita5ons
based
on
line-‐of-‐sight:
one
factor
affec5ng
ability
to
detect

acous5c
signals
(acous5c
capabili5es
in
water/boeom
layer
interference)

Applica5on
to
Fisheries
Management:

  Complex
movement
paeerns
over
5me
-‐
quan5fica5on
of
home
ranges

  Marine
Reserves
to
fulfill
conserva5on
func5on:
accurate
designa5on
of

reserve
boundaries
large
enough
to
encompass
full
range
or
networks
along

pathways:
account
for
daily,
intermediate
&
ontogene5c
movements

  Avoid
cutng
through
reef
plavorms
(e.g.,
300m
range)

  Only
adults
crossing
large
boundaries:
Marine
Reserve
networks
consider

movement
capabili5es
(inshore,
mid-‐shelf,
shelf-‐edge)

  Digi5zing,
modifica5on,
enhancement
of
benthic
habitat
maps
&
spa5al

analyst
mapping
techniques
allow
for
accurate
ID
of
habitat
u5liza5on

paeerns,
facilitate
future
planning

for
conserva5on
management

Acknowledgements

-Dr. Appeldoorn
-Graduate Committee
-Department of Marine Sciences
-Fish Lab
-Tag Team

CRES

CSCOR

Thesis presentation final

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