DFO Gulf Region European Green Crab Monitoring Dataset

PURPOSE:
Provide presence/absence and abundance data for the non-indigenous and invasive European green crab (EGC) in selected southern Gulf of St. Lawrence (sGSL) estuaries along the Northumberland Strait coast of New-Brunswick and eastern Prince-Edward-Island.

DESCRIPTION:
Temporal monitoring during ice-free seasons of European green crab abundance is completed in response to previous regional population declines in the Maritime provinces.

Note that where presence is not indicated on the map does not mean absence - this survey is limited to a few sites.

Traps that did not fish correctly were not included in the dataset. Examples of defective traps include: an open trap, an open bait container, a trap filled with algae and falling into the open position, a trap that has not been fished for over 48 hours, an overturned trap, or a trap that has been significantly moved or otherwise tampered with.

Population estimates are not derived from this data.

PARAMETERS COLLECTED:
1) EGC count, size measurement, sex, and catch weight
2) Counts of bycatch species. Categories reported in this dataset are finfish (cunner, striped bass, mummichog, winter flounder, smooth flounder, sculpin, tomcod, American eel, banded killifish, flounder, unknown bony fish), Atlantic rock crab, American lobster, and other (lion's mane jellyfish, moon jellyfish, other crabs, moon snail). Other smaller species were often in the trap but were not included as bycatch in this dataset as they can easily escape the mesh size and would not consistently be trapped.
3) Environmental data: water depth at trap setting, sediment type, vegetation types noted, salinity, water temperature, dissolved oxygen (not included), specific conductance (not included), conductivity (not included), weather, cloud cover (not included), tide state and direction (upon fishing).

NOTES ON QUALITY CONTROL:
Data entry of morphological parameters randomly verified for accuracy.

Weights are not reported for PEI sites due to inconsistencies with types of weighing scales and measurement protocols.
PHYSICAL SAMPLE DETAILS:
Whole European green crab specimens

SAMPLING METHODS:
Baited trapping with Fukui traps. Bait was in a bait can or bag. Types of bait included herring (predominant type used), as well as other species when herring were not available (gaspereau, canned fish [tuna, kippers, snack sardines], mackerel, tilapia, and perch).

USE LIMITATION:
To ensure scientific integrity and appropriate use of the data, we would encourage you to contact the data custodian.