Fishing during extreme heatwaves alters ecological interactions and increases indirect fishing mortality in a ubiquitous nearshore system

PURPOSE: The data files contained herein are meant to serve as supplementary material for a published paper regarding the effects of clam digging during extreme heat waves on predator-prey interactions and indirect fishing mortality. This page will be updated with the complete citation for the article once it is officially published.

DESCRIPTION: The increasing frequency and severity of heatwaves driven by global climate change are projected to have multifaceted ecological effects. While studies have assessed the impacts of heatwaves at the organism and population level, field-based studies documenting the effects of heatwaves on in situ ecological interactions are rare. Furthermore, studies assessing the biological and ecological implications of direct anthropogenic disturbance during heatwaves are absent. Here, we leverage mesocosm field experiments to document the effects of human activity (clam fishing) during an extreme heatwave on a ubiquitous predator-prey system at the land-sea interface: nearshore crabs and their bivalve prey. In monthly field experiments from May to September, we simulated clam fishing at low tide and subsequently returned marked, sub-legal sized clams to the sediment surface at three different tide levels; predator exclusion containers were used to protect half of the clams from crab predation. Reburrowing and mortality rates were recorded immediately after fishing and after 24- and 48 hours. Results showed that, typically, indirect fishing mortality was low and the vast majority of clams reborrowed within 24 hours. However, during an extreme heatwave in June, the clams appeared visually unhealthy during fishing and failed to reborrow, leading to near complete mortality during the heatwave. Estimates of predator activity were ≈5× higher during the heatwave compared to other months, and the majority of indirect fishing mortality was attributable to predation. When put into the context of air temperature thresholds, there was a clear shift after 30ºC, whereby clam reborrowing plummeted, and predator activity and mortality increased dramatically. Ultimately, our study provides strong field-based evidence that ecological shifts during heatwaves, facilitated by altered organismal physiology, can drive substantial indirect fishing mortality in a nearshore fishery where such mortality is otherwise low. These results not only provide support for climate driven alterations to predator-prey dynamics and ecosystem function but generate pertinent information for an ecosystem approach to fisheries management.

PARAMETERS COLLECTED: Clam size (shell length) Clam reborrowing rates Clam mortality rates Predator activity estimates Air temperature

NOTES ON QUALITY CONTROL: Data collected by Jeff Clements, Sarah Harrison, Mylène Roussel, Jillian Hunt, Brooke-Lyn Power, and Courtney Jones. Original data entry by Sarah Harrison. Data checked and validated prior to analysis by Jeff Clements. Data further checked and validated prior to publication by CADI.

PHYSICAL SAMPLE DETAILS: No physical samples retained; all observations and counts conducted directly in the field.

SAMPLING METHODS: i. Experimental fishing for soft-shell clams ii. Experimental manipulation of crab access to clams (predator inclusion/exclusion experiments) iii. Observations of clam burrowing behaviour and mortality iv. Counts of predators and scavengers within experimental manipulations v. Data mining air temperature (ECCC historical data website)

USE LIMITATION: Please contact the data custodians before attempting to use this information in support of any kind of scientific analyses.

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• Aquatic wildlife
• Marine biology
• Nature and Environment
• Science and Technology

Additional Info

• Maturity Level 1 (54%)
• Maturity Level 2 (38%)
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Field	Value
Last Updated	October 20, 2025, 02:38 (UTC)
Created	October 20, 2025, 02:38 (UTC)
Domain / Topic Domain or topic of the dataset being cataloged.	Biota, Environment, Oceans
Title Title for the Dataset.	Fishing during extreme heatwaves alters ecological interactions and increases indirect fishing mortality in a ubiquitous nearshore system
Description A description of the dataset.	PURPOSE: The data files contained herein are meant to serve as supplementary material for a published paper regarding the effects of clam digging during extreme heat waves on predator-prey interactions and indirect fishing mortality. This page will be updated with the complete citation for the article once it is officially published. DESCRIPTION: The increasing frequency and severity of heatwaves driven by global climate change are projected to have multifaceted ecological effects. While studies have assessed the impacts of heatwaves at the organism and population level, field-based studies documenting the effects of heatwaves on in situ ecological interactions are rare. Furthermore, studies assessing the biological and ecological implications of direct anthropogenic disturbance during heatwaves are absent. Here, we leverage mesocosm field experiments to document the effects of human activity (clam fishing) during an extreme heatwave on a ubiquitous predator-prey system at the land-sea interface: nearshore crabs and their bivalve prey. In monthly field experiments from May to September, we simulated clam fishing at low tide and subsequently returned marked, sub-legal sized clams to the sediment surface at three different tide levels; predator exclusion containers were used to protect half of the clams from crab predation. Reburrowing and mortality rates were recorded immediately after fishing and after 24- and 48 hours. Results showed that, typically, indirect fishing mortality was low and the vast majority of clams reborrowed within 24 hours. However, during an extreme heatwave in June, the clams appeared visually unhealthy during fishing and failed to reborrow, leading to near complete mortality during the heatwave. Estimates of predator activity were ≈5× higher during the heatwave compared to other months, and the majority of indirect fishing mortality was attributable to predation. When put into the context of air temperature thresholds, there was a clear shift after 30ºC, whereby clam reborrowing plummeted, and predator activity and mortality increased dramatically. Ultimately, our study provides strong field-based evidence that ecological shifts during heatwaves, facilitated by altered organismal physiology, can drive substantial indirect fishing mortality in a nearshore fishery where such mortality is otherwise low. These results not only provide support for climate driven alterations to predator-prey dynamics and ecosystem function but generate pertinent information for an ecosystem approach to fisheries management. PARAMETERS COLLECTED: Clam size (shell length) Clam reborrowing rates Clam mortality rates Predator activity estimates Air temperature NOTES ON QUALITY CONTROL: Data collected by Jeff Clements, Sarah Harrison, Mylène Roussel, Jillian Hunt, Brooke-Lyn Power, and Courtney Jones. Original data entry by Sarah Harrison. Data checked and validated prior to analysis by Jeff Clements. Data further checked and validated prior to publication by CADI. PHYSICAL SAMPLE DETAILS: No physical samples retained; all observations and counts conducted directly in the field. SAMPLING METHODS: i. Experimental fishing for soft-shell clams ii. Experimental manipulation of crab access to clams (predator inclusion/exclusion experiments) iii. Observations of clam burrowing behaviour and mortality iv. Counts of predators and scavengers within experimental manipulations v. Data mining air temperature (ECCC historical data website) USE LIMITATION: Please contact the data custodians before attempting to use this information in support of any kind of scientific analyses.
Tags / Keywords Keywords/tags categorizing the dataset.	Aquatic wildlife Marine biology Nature and Environment Science and Technology
Format (CSV, XLS, TXT, PDF, etc) File format of the dataset.
Dataset Size Dataset size in megabytes.
Metadata Identifier Metadata identifier – can be used as the unique identifier for catalogue entry
Published Date Published date of the dataset.	2024-12-18
Time Period Data Span (start date) Start date of the data in the dataset.
Time Period Data Span (end date) End date of time data in the dataset.
GeoSpatial Area Data Span A spatial region or named place the dataset covers.

Field	Value
Access category Type of access granted for the dataset (open, closed, service, etc).
License License used to access the dataset.	Open Government Licence - Canada
Limits on use Limits on use of data.
Location Location of the dataset.	https://open.canada.ca/data/en/dataset/1bf057da-8280-11ef-8cce-55cc7f028297
Data Service Data service for accessing a dataset.
Owner Owner of the dataset.	Fisheries and Oceans Canada | Pêches et Océans Canada
Contact Point Who to contact regarding access?	Government of Canada; Fisheries and Oceans Canada, 506-229-7798, [email protected]
Contact Point Email The email to contact regarding access?
Publisher Publisher of the dataset.
Publisher Email Email of the publisher.	[email protected]
Author Author of the dataset.
Author Email Email of the author.
Accessed At Date the data and metadata was accessed.

Field	Value
Identifier Unique identifier for the dataset.
Language Language(s) of the dataset
Link to dataset description A URL to an external document describing the dataset.
Persistent Identifier Data is identified by a persistent identifier.
Globally Unique Identifier Data is identified by a persistent and globally unique identifier.
Contains data about individuals Does the data hold data about individuals?
Contains data about identifiable individuals Does the data hold identifiable data about individual?
Contains Indigenous Data Does the data hold data about Indigenous communities?
Portal Type Platform type of the source portal.

Field	Value
Version Version of the datatset	None
Source Source of the dataset.	None
Version notes Version notes about the dataset.
Is version of another dataset Link to dataset that it is a version of.
Other versions Link to datasets that are versions of it.
Provenance Text Provenance Text of the data.
Provenance URL Provenance URL of the data.
Temporal resolution Describes how granular the date/time data in the dataset is.
GeoSpatial resolution in meters Describes how granular (in meters) geospatial data is in the dataset.
GeoSpatial resolution (in regions) Describes how granular (in regions) geospatial data is in the dataset.

Field	Value
Indigenous Community Permission Who holds the Indigenous Community Permission. Who to contact regarding access to a dataset that has data about Indigenous communities.
Community Permission Community permission (who gave permission).
The Indigenous communities the dataset is about Indigenous communities from which data is derived.

Field	Value
Number of data rows If tabular dataset, total number of rows.
Number of data columns If tabular dataset, total number of unique columns.
Number of data cells If tabular dataset, total number of cells with data.
Number of data relations If RDF dataset, total number of triples.
Number of entities If RDF dataset, total number of entities.
Number of data properties If RDF dataset, total number of unique properties used by the triples.
Data quality Describes the quality of the data in the dataset.
Metric for data quality A metric used to measure the quality of the data, such as missing values or invalid formats.

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