Dataset: lobster recapture data
Deployment: NEC-DC2002-1

Mapping Spawning and Hatching Grounds of the American Lobster Tagging Data: detailed lobster recapture data

Principal Investigator:

Diane Cowan

Project:

Northeast Consortium: Cooperative Research (NEC-CoopRes)

Data URL:

https://www.bco-dmo.org/dataset-deployment/451262/data

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Description

Mapping Spawning and Hatching Grounds of the American Lobster
Tagging Data

Project Leader: Diane Cowan, The Lobster Conservancy

Additional Participants: Mathew Thomson, F/V Shearwater
Win Watson, University of New Hampshire
Matthew Weber
Andrew Solow, Woods Hole Oceanographic Institution
Mark Wallace, F/V Pamela B
Tim Thompson, F/V Haley & Amy
Bill Rourke, F/V A-Bill
Michael Reny
Richard Nelson, F/V Pescadero
Peter Murphy
Jon Murphy, F/V Redeemed
Steve Lash, F/V Streaker II
Troy Hayes, F/V Gray Ghost
Mark Havener, F/V Sarah Ashley
Philip Genthner, F/V Melinda Kay
Darrell Brazier, F/V Amy Sue
Nick Caloyianis, Caloyianis Productions, Inc.
Clarita Berger, Caloyianis Productions, Inc.
Richard Barter, F/V Tammy Jeane II
Kevin Benner, F/V Wanda Marie
Rex Benner, F/V Sydni & Erik
Denny Benner, F/V Maureen R
Jim Bolen, F/V Finest Kind
Philip Bramhall, F/V Amanda Kate

The Lobster Sonar Tracking Project was launched in late summer 2002, and was implemented for 2 tracking seasons. In September and October of the first season (2002) a total of 191 egg-bearing females were tagged: lobster IDs: 001 - 193. These lobsters were then tracked over the subsequent 13 months. In August and September of 2004 - the second season of the project - 45 egg-bearing females AND 41 males were tagged, a total of 86 lobsters: lobster IDs: 300 - 400.

Each lobster was tagged with three pieces of equipment: a sonar transmitter that emits a unique frequency/code combination, a temperature datalogger ("Tidbit") that records the ambient water temperature every hour, and a ribbon tag with the lobster's ID and The Lobster Conservancy (TLC) phone number to identify the lobster in the event of recapture. Participants were equipped with vessel-based hydrophones to periodically "listen" for sonar signals throughout their fishing territory. Frequency and code were recorded from each observed signal and the lobster ID was subsequently looked up. Hence, the tagged lobsters could be tracked any one of three ways: via hydrophone, trap recapture, or SCUBA dive recapture (using an underwater dive receiver). Information on lobster egg state could only be collected upon recapture. Likewise, temperature data collected by the Tidbit was only useful if the logger was recovered upon recapture and the information downloaded. Temperature data on 30 lobsters from the 2002-2003 season and 18 lobsters from the 2003-2004 season were downloaded as well as data from stationery loggers. Each lobster ID in that data object corresponds to lobster IDs in the associated data objects.

Project website: http://www.lobsters.org

Associated data: water temperature, lobster tracking data, and lobster recapture data

Lobster Tag Data:
South missing
4=dbl crusher
5=dbl seizer 0 if lobster is missing no appendages;
If appendages are missing (other than antennae), this is the number of missing claws,
plus legs, plus maxillipeds, plus uropods.
(see 'comments' for which appendages are missing) 4= hatching explanation of the use of this code)

Validity code:
There is obviously room for human error in the collection of these data, and potential equipment errors as well. Incorrect sonar codes can be recorded, data can be incorrectly entered into the database, and sonar tags can and have fallen off lobsters without the investigators' knowledge (they will continue beeping away on the ocean floor). Therefore, the most confident tracking data was collected on a lobster that was subsequently recaptured (with the sonar tag still visibly attached). Slightly less confidence was awarded to tracking data on a lobster that showed movement, but has not been subsequently recaptured to verify sonar tag presence. Least confidence and most suspicion exists for tracking data that indicates a sonar tag has not moved for some time, and the lobster has not been subsequently recaptured. This indicates a good possibility that the tag has fallen off. Furthermore, through spatial analysis of most of the individual lobster tracks in GIS mapping software, a number of specific data points were noted that were either highly suspicious or downright impossibilities.

If a recapture showed that the sonar tag was missing, then every prior tracking record for that lobster received a "transmitter detached" reflecting uncertainty as to when the tag was lost. "Disappeared" means the lobster was never tracked or recaptured. Based upon spatial analysis we were able to determine that some of the tracking entries were "invalid", while others were "suspect". These validity descriptions are complete for every lobster tracked during the first year of the project, but not yet complete for the second year.

Revised Sept 05, 2006; gfh

Methods & Sampling

Dataset acquisition description

It was found that although small female lobsters were abundant in Muscongus Bay, most were not ovigerous. Small ovigerous lobsters tended to spawn and remain inside the bay where they brooded at lower winter, but higher spring and summer temperatures than large ovigerous lobsters. In contrast, large ovigerous lobsters (>size at 50% maturity) were relatively rare, but most were ovigerous. They tended to spawn at greater distances from shore and while many stayed near where they spawned, others achieved a maximum displacement of up to 240 km. Large ovigerous lobsters were at more moderate temperatures throughout the year regardless of how far they traveled. Both small and large ovigerous lobsters experienced (1) sufficiently low winter temperatures for successful ovarian maturation, and (2) approximately the same number of degree days for egg development. These findings suggest that known thermal requirements of optimal cold temperature for successful ovarian maturation are balanced with sufficient numbers of degree-days for egg development via two distinct behaviors. Small ovigerous lobsters remain in shallow water where they experience colder winter but warmer spring and summer temperatures than large ovigerous lobsters that move to deeper water with warmer winter but colder spring and summer temperatures."

Deployment-specific acquisition description

Data Processing Description

Dataset Processing Description

"The purpose of this study was to investigate the relationship between temperature, movements, and body size for ovigerous (egg-bearing) lobsters tagged recently after spawning and tracked throughout the 9-13 month brooding period. We made predictions about where and under what temperature conditions small (< size at 50% maturity) versus large (> size at 50% maturity) lobsters would brood.

Deployment-specific processing description

More information about this dataset deployment

Instruments

Lobster Trap

Supplied Description:

Instrument Type

Generic Name: Lobster Trap

Acronym: Lobster Trap.

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/90/

Generic Description:

A lobster trap (often called a lobster pot) is a baited trap which traps lobsters or crayfish and is used in lobster fishing. A lobster trap can catch multiple lobsters at once and can be a various sizes. An opening permits the lobster to enter a tunnel of netting and proceed into a "chamber" or "kitchen", where there is bait, and then into the "parlor" from which it cannot escape.

Parameters

Supplied Name	Supplied description	Standard Name
year	year in which lobster was recaptured	year
yrday_local	day of the year, Julian Day, local time	yrday_local
day_local	day of the month, local time	day_local
month_local	month of the year, local time	month_local
lob_id	lobster identification number; this number is on ID tag and TidbiT; TidbiT isprogrammed to this number	no_bcodmo_term
lat	latitude where lobster was captured	lat
lon	longitude where lobster was captured, negative = West	lon
depth_w	depth of the water where lobster was captured	depth_w
bottom_type	brief description of bottom	no_bcodmo_term
location_desc	information about where lobsters were recaptured	no_bcodmo_term
sex	Male; Female; Unknown;	sex
eggs_present	Is the lobster brooding eggs? Yes or no	no_bcodmo_term
num_eggs	none; very few; few; 1/2 gone; full;	no_bcodmo_term
egg_color	clear; green; opaque; black; brown; light; eyed; orange/red;	no_bcodmo_term
egg_stage	0 = none 1 = recently spawned 2 = early intermediate 3 = late intermediate 4 = eyed; ready to hatch 5 = hatching 6 = recently hatched	no_bcodmo_term
num_claws	0 = no claws; pistol 1 = one claw; cull 2 = two claws	no_bcodmo_term
sonar_tag_cond	none released = lobster released with sonar tag returned = tag returned to The Lobster Conservancy	no_bcodmo_term
tidbit_cond	released = lobster released with tag still attached returned = tagged turned in; stored at Lobster House replaced = missing or damaged tag was replaced with new tag none = no TidbiT attached to lobster at time of capture unknown = unknown no blink = TidbiT not flashing	no_bcodmo_term
tidbit_download	False = A temperature data logger (TidbiT) was recovered,but failed for some reason. For instance, it was worn down and destroyed by the lobster rubbing it against rocks. True = A TidbitT was recovered and gave data.	no_bcodmo_term
id_cond	yes = fine none = missing tag 1/2 missing = tag 1/2 gone replaced = missing tag replaced with new number removed = harvester removed tag	no_bcodmo_term
data_source		no_bcodmo_term
validity_code	NSR = not subsequently recaptured; SR = Subsequently recaptured; (see below for an expandedexplanation of the use of this code)	no_bcodmo_term
comments	Comments by trackers or comments related to the signal reception	comment

Database

Contribute Data

Dataset: lobster recapture data
Deployment: NEC-DC2002-1

Mapping Spawning and Hatching Grounds of the American Lobster
Tagging Data

Dataset acquisition description

Deployment-specific acquisition description

Dataset Processing Description

Deployment-specific processing description

Database

Contribute Data

Dataset: lobster recapture dataDeployment: NEC-DC2002-1

Mapping Spawning and Hatching Grounds of the American Lobster Tagging Data

Dataset acquisition description

Deployment-specific acquisition description

Dataset Processing Description

Deployment-specific processing description

Dataset: lobster recapture data
Deployment: NEC-DC2002-1

Mapping Spawning and Hatching Grounds of the American Lobster
Tagging Data