Download PDF - COINAtlantic

Methods11 th International Symposium for GIS and Computer Cartography for Coastal Zones ManagementMapping and analysis were crucial to the project and the work needed to be transparent and trusted by both parties.To that end, spatial data were made available to the conservation groups by the Department of Fisheries andOceans (DFO), and analysis was undertaken by analysts at DFO and conservation organizations Living OceansSociety and David Suzuki Foundation. All results were shared and discussed with all parties.A large component of the low sustainability rating (red score) for bottom trawl fishery products was due to thelack of any habitat mitigation in the fishery, aside from closures to protect the Hecate Strait hexactinellid spongereefs. Sustainable seafood rating criteria dictate that a fishery using unmodified bottom trawl gear that continuallycontacts the seabed cannot be rated green; therefore the goal was to find new measures that may achieve a yellowscore. Spatial measures focused on developing a restricted footprint that prevented further spatial expansion, excludedareas of historically high coral and sponge bycatch, and limited overlap with each type of benthic habitat to 50%or less.One of the first challenges of the project was mapping the area of potential impact for each tow. DFO maintains adatabase of trawl data on a tow by tow basis. Historical trawl and bycatch data used in this project were summarisedinto 1x1 km blocks by DFO to facilitate analysis and remove sensitive information and data outliers. The methodassumed that tows follow a straight line between start and end point when, in fact, tows often follow depth contoursrather than straight lines. However, mid-point locations are not consistently recorded, leaving no option but toacknowledge the limitation and potential introduction of error and bias and to recommend consistent collection ofmidpoint locations in future.Information on the distribution of historical trawl effort (1996–2009) by fisheries management statistical areaand depth class was tabulated. Statistics quantifying the overlap of historical bottom trawl locations and alternatedraft footprints (i.e., intersection) with numerous data layers were repeatedly generated. ModelBuilder in ArcMAP9.3 was used to facilitate the time-consuming and repetitive analyses. Data layers compared with fishery footprintsincluded 200 m depth classes to 1200 m deep, surficial geology (Natural Resources Canada), Provincial marineecosections (Province of British Columbia, 2002), benthic classes (BCMCA, 2011), areas of high rugosity(BCMCA, 2011), areas of high coral and sponge bycatch from fishery data and systematic survey data (DFO), 12proposed coral and sponge protection areas (Ardron, 2005), and modelled coral habitat (Finney, 2009). For layersthat provided comprehensive coverage of the trawl footprints (i.e., depth classes, ecosections, benthic classes, andrugosity), we tallied the area in km 2 of each benthic class or ‘habitat type’ within the dominant ecosections wherethe trawl fishery operates, and compared that to the area inside the historic footprint and proposed new boundaries.Adjustments to the new footprint were iterative and the process included in-depth consultations with trawl fishermenand with other environmental organisations. The environmental groups also identified and mapped two types ofareas at risk to future habitat damage that remained within the footprint. Areas of historically repeated bycatch ofcoral and sponge were delineated using coral and sponge bycatch data and areas previously untrawled but remaininginside the footprint were identified.ResultsThe groundfish bottom trawl footprint or allowable area for this fishery, previously without depth restriction, wasreduced to the most important areas. Overall, the total area was decreased by 20% and the deepest fishing area, below1000 m, was decreased by 65% (Figure 1). We did not succeed in limiting overlap of the agreed upon footprintto 50% or less in every depth class (Table 1). Some areas inside the footprint remain untrawled but were required foroperations (e.g., vessel and net manoeuvring) and some areas have seen very little effort (2–10 tows). These considerationsare not taken into account in Table 1.Although the environmental groups tried to have additional areas of high risk of future habitat damage removedfrom the footprint, industry declined because some of the areas were historically important and productive fishinggrounds and/or were required for operations. It was expected that non-spatial management measures would mitigatebycatch concerns. The non-spatial measures included a system of individual vessel bycatch limits designed to providea disincentive for fishing in potentially risky areas within the footprint. Since it was impossible to identify everypossible area with corals and sponges, this system of individual vessel bycatch quotas was viewed as the mosteffective way of providing protection to sensitive areas remaining within the footprint, as long as it was well enforced.The observer program, with 100% coverage, provides the means for effective enforcement. In addition, an192