Using Siphon Hole Morphometrics to Identify, Count, and Measure Soft-shell Clams (Mya arenaria)

PURPOSE:

Establishing efficient, non-destructive sampling methods for clam population assessments.

DESCRIPTION:

In the Gulf of St. Lawrence (GSL) Management Region, clam assessments are uncommon due to limited resources and the labour-intensive nature of sampling clam beds. Furthermore, clam assessments typically rely on destructive sampling that disturbs sediment and removes animals from their habitat. Establishing efficient, non-destructive sampling methods for clam population assessments can reduce the impact of scientific sampling on these habitats and provide for more efficient monitoring. In this study, we tested the idea that visually observing siphon holes on the sediment surface could predict the presence, number, and size of soft-shell clams across different sites in the southern GSL. Siphon holes reasonably predicted the presence, number, and size/biomass of soft-shell clams in most, but not all, sites. Thus, in many habitats in the GSL, siphon holes can be used for population assessments, providing a powerful tool to enhance Science advice to fisheries managers.

Data was collected at the following sites:

• Maisonnette, Parc Maisonnette, Maisonnette, New Brunswick, Canada

• Kouchibouguac, Loggiecroft wharf, Kouchibouguac National Park, New Brunswick, Canada

• Shemogue, Amos Point Road, Little Shemogue, New Brunswick, Canada

• Powell's Cove, Powell's Point Provincial Park, Little Harbour, Nova Scotia, Canada

PARAMETERS COLLECTED:

• Clam abundance

• Clam biomass (total sample)

• Clam size (length, weight)

• Siphon hole abundance

• Siphon hole size

• Siphon hole characterization (i.e., identification of actual clam based on shape)

• Seawater temperature

• Sediment grain size

• Sediment organic content (%)

• Sediment relative moisture content (%)

NOTES ON QUALITY CONTROL:

Original data entry by Jillian Hunt and/or Isabelle Brennan. Data checked and validated prior to analysis by Jeff Clements. Data further checked and validated prior to publication by Amélie Robichaud.

PHYSICAL SAMPLE DETAILS:

No physical samples retained.

• Clam samples returned back to original habitat after measuring and weighing in the field.

• Sediment core samples stored in walk-in freezer and discarded after processing and analysis.

SAMPLING METHODS:

i. Identifying, counting, weighing, and measuring (with calipers) clams

ii. Identifying, counting, and measuring (with calipers) clam siphon holes

iii. Seawater temperature monitoring via data loggers

iv. Sediment grain size, organic content, and moisture content analysis

USE LIMITATION:

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