Litter audits in Canadian harbor environments require structured field documentation that captures both the type and quantity of debris encountered, along with location data sufficient for repeat surveys. The data sheets described here follow an approach consistent with the UNEP Guidelines on Marine Litter Monitoring and are adapted to the specific conditions of Canadian port zones, including tidal variation, seasonal ice cover, and the regulatory distinction between federal and local harbor authority areas.
Marine debris survey in coastal harbor waters. Photo: NOAA / Wikimedia Commons (public domain).
Purpose of Litter Audit Data Sheets
A litter audit data sheet is a standardized field form used to record debris types, quantities, and locations during a structured survey of a harbor area. Consistent data collection allows comparisons across survey periods, supports regulatory reporting, and provides evidence for targeted cleanup planning.
Canadian port operators conducting voluntary cleanup surveys or fulfilling obligations under harbor authority agreements typically need to document the following categories of information during each audit session.
Core Data Fields
Location and Survey Metadata
Each data sheet entry should record:
- Harbor name and port authority jurisdiction (e.g., Vancouver Fraser Port Authority, Port of Halifax)
- Survey zone identifier (dock section, berth range, or GPS coordinates)
- Date, start time, and end time of survey
- Tide height at survey start (referenced to Canadian Chart Datum)
- Weather conditions: wind speed, precipitation, visibility
- Survey method: shoreline transect, vessel-based visual survey, or dive survey
- Surveyor name and organization
Debris Classification Categories
The following classification scheme is adapted from the NOAA Marine Debris Monitoring and Assessment framework:
| Category Code | Category Name | Examples |
|---|---|---|
| PL | Plastic — Hard | Crates, containers, buckets, caps |
| PF | Plastic — Film/Flexible | Bags, sheeting, packaging wrap |
| FG | Fishing Gear | Nets, lines, traps, buoys, bait bags |
| RB | Rubber | Tires, gaskets, hose sections |
| GL | Glass / Ceramic | Bottles, jars, fragments |
| MT | Metal | Cans, cables, anchor chain sections |
| WD | Processed Wood | Pallets, lumber, dock board sections |
| CL | Cloth / Textile | Rope (non-fishing), fabric, netting |
| HZ | Hazardous Material Containers | Fuel cans, chemical drums, battery casings |
| OT | Other / Unclassified | Items not fitting above categories |
Quantity Recording Methods
Two methods are in common use for Canadian harbor audits:
Item Count Method
Each discrete item is counted individually and recorded against its category code. This is the preferred method for high-debris areas where items can be physically accessed for collection. It produces an exact count of removable debris per survey zone.
Weight Estimation Method
For submerged debris or surveys where full collection is not feasible, visual estimates of debris density are converted to weight ranges using reference tables. This method is less precise but allows documentation of debris that cannot be safely or legally removed during the survey session.
For surveys involving fishing gear at depth, DFO recommends recording GPS coordinates and approximate depth alongside category codes, as this data is required for recovery operation planning. See the DFO Lost Gear Recovery documentation.
Tidal and Seasonal Considerations
Canadian harbors experience a wide range of tidal conditions. Ports on the Bay of Fundy, such as Saint John, have tidal ranges exceeding 10 meters, which dramatically affects both survey access and debris distribution. Surveys in such locations should be timed to occur within one hour of low tide to maximize the area of visible shoreline debris.
Pacific coast harbors, including Vancouver and Prince Rupert, experience mixed semi-diurnal tides with typical ranges of 3–5 meters. Surveys here benefit from coordination with the Canadian Hydrographic Service tidal predictions.
During winter months, ice cover along harbor surfaces in Atlantic and inland ports may prevent visual surface surveys. In these conditions, documentation is typically deferred to spring thaw surveys, which often reveal debris displaced or concentrated by ice movement.
Photo Documentation Requirements
Field photographs are an essential component of a complete audit record. Each survey zone should include:
- An orientation photo showing the survey zone boundary
- Representative photos of the predominant debris types found
- Close-up photos of any hazardous material containers or fishing gear (before and after tagging)
- GPS-tagged photos where device capability allows
Photos should be filed with the audit data sheet, cross-referenced by survey zone identifier and date.
Reporting and Data Retention
Completed data sheets are typically retained by the organization conducting the audit. Where surveys are conducted under a port authority agreement or as part of a DFO data collection exercise, copies may be submitted to the relevant authority. Retention periods vary by port authority. Federal port authorities operating under the Canada Marine Act may specify retention requirements in harbor operating agreements.
For long-term trend analysis, consistent use of survey zone identifiers and debris classification codes across multiple audit periods is more valuable than any single survey record.