Transcript Movement patterns and distribution of the nearshore crab

Autonomous vehicle monitoring of
movement and habitat use by mobile
nearshore species
Patrick Lane
University of Alaska Fairbanks
School of Fisheries and Ocean Sciences
Introduction
Goals
Study Site and Test Species
Completed Work
Habitat Surveys
Test Species Abundance Surveys
Preliminary Movement Information
Conclusions
Future Directions
Acknowledgements
Julie Nielson
Introduction
• Sampling the distribution of nearshore, subtidal species can be
difficult.
• Movement patterns complicate the study of distribution and have
important ecological and conservation implications.
• Mobile organisms: energy transfer, spatial scale, conservation strategy
• Value of measuring animal movement
NOAA AFSC
(Pittman and McAlpine 2001, Holsman et al. 2006).
NOAA AFSC
VEMCO Inc.
Introduction
•
•
•
•
Movement, habitat use and spatial management strategies
Nearshore movement assessment techniques
Nearshore habitat use assessment techniques
Ultrasonic telemetry
NOAA AFSC
Julie Nielson
Paul Mahacek SCU RSL
Goals
NOAA
1) Design and test an autonomous surface vehicle (ASV) telemetry
monitoring scheme (SCU RSL).
2) Compare movement rates to manual telemetry monitoring.
3) Use side-scan sonar habitat maps and ASV telemetry data to monitor
habitat use (NOAA Hydropalooza).
– Compare to diver visual observations of tagged individuals
4) Assess seasonal changes in habitat structure.
– Seasonal variability in habitat structure and integrity of one-time remote
mapping
Kasitsna Bay
•
•
•
•
Adjacent to NOAA/UAF Kasitsna Bay Laboratory
Variable habitat structure
Depth less than 40 m
Abundance of test organism: the helmet crab (Telmessus cheiragonus)
Kachemak Bay
Homer
Kasitsna
Bay
Seldovia
UAF Kasitsna Bay Laboratory
Test Species:
Telmessus cheiragonus
•
•
•
•
Reaches a size of up to 10 cm carapace length
Intertidal to 110 m but not common below 30 to 40 m
Bristled carapace allows for easy attachment of tags
Found in a variety of habitats ranging from silt to rock seafloor
NOAA/ Jan Haaga
Completed Work
• Habitat Availability
– Quantify habitat structure
– Assess habitat variability
• Test Species Abundance
– Quantify availability
– Placement of future collections
• Preliminary Movement Information
– Area to monitor vs. area used for tagging
Methods: Habitat Availability
• July and August 2008
• 12 30 m transects across 4 randomly placed sites 5 , 10 , 15 m
• 6 randomly placed 1 x 1 m quadrats
– % cover understory algal canopy
– % cover substrate(silt, sand, gravel, cobble, boulder, bedrock, shell debris)
• Rugosity measured at 6 random points
Kasitsna
Bay
UAF Kasitsna
Bay Laboratory
Results: Habitat Availability
15 m
10 m
5m
(Average + 1SD)
Percent Cover
100
102
80
N=4
N=4
N=4
60
40
20
Rugosity: 100.7 – 109.0 cm/m
No significant difference based on depth (Tukey’s HSD p > 0.05)
Methods: Test Species Abundance
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•
•
•
•
July and August 2008
Same sites surveyed as for habitat availability surveys
12 30 x 4 m (120 m2) transects across 4 sites at 5, 10, 15 m
All test species counted, measured, and sexed
Size threshold: 11 individuals collected, measured, and weighed
Results: Test Species Abundance
Number of Individuals per 120m2
(Average + 1SD)
• Carapace length of 40 mm is the minimum size to tag
• Only 4 females in all 12 transects
• Abundance for males is shown:
10m
10
5 5m
7
6
5
4
3
2
1
0
N=4
S
<40 mm
L
>40
mm
7
6
5
4
3
2
1
0
15 m
15
N=4
S
<40 mm
L
>40 mm
Size (carapace length in mm)
7
6
5
4
3
2
1
0
N=4
S
<40 mm
L
>40 mm
Methods: Preliminary Movement
Information
• November 2008: 4 male test organisms tagged with VEMCO V9
ultrasonic transmitters using epoxy and fiberglass
• February 2009: Study site monitored using manual telemetry and
locations of three tagged individuals recorded using GPS
• Point-to-point minimal movement estimates calculated using UTM
coordinates (84-85 days between release and monitoring)
(Taggert et al. 2007)
Results: Movement
• Minimal movement
estimates (84-85 days)
• Future monitoring
planned
281 m
Kachemak
Bay
Kasitsna
Bay
31 m
100 m
84 m
Not Located
USGS
Conclusions
• Habitat Availability:
John Thedinga
– Substrate type and algal cover
– Variable across site
NOAA/ Jan Haaga
• Test Species Abundance:
– Male individuals will be used for future tagging
• Preliminary Movement Information:
– Within study area so far
– Range of distances moved
Mike Kenner UCSC
Future Directions
• Habitat mapping (NOAA Hydropalooza).
• Scuba habitat availability surveys (summer, fall, winter, spring)
• Manual tracking, diver observations and autonomous surface vehicle
ASV tracking (summer 2009 to summer 2010)
• Comparison of ASV tracking and sonar mapping approach to manual
telemetry and scuba habitat observations
– Movement rates and habitat use data
Paul Mahacek SCU RSL
Acknowledgements
Advisory Committee
Brenda Konar, Ginny Eckert, Stephen Jewett
Funding
-Rasmuson Fisheries Research Center
-NOAA West Coast and Polar Regions Undersea Research Center
-Vemco Inc.
NOAA/UAF Kasitsna bay Laboratory
Dave Christie, Kris Holderied, Hans Pederson
Field Volunteers
Melissa Deiman, Terry Efird, Heloise Chenalot, Toben Spurkland,
Nathan Stewart, Martin Shuster, Renato Boras