Gill nets are used in index netting projects such as Fall Walleye Index Netting (FWIN). This type of project can assess population density and abundance of fish stocks through biological measures and indicators.
The A/OFRC deploys gill nets according to specific standards set forth by the Ontario Ministry of Natural Resources so that results are standardized and can be duplicated. Depending on the species targeted, time limits for sets vary from one hour to twenty-four hours. Unfortunately with this method, some fish need to be sacrificed in order to conserve the greater population. The important data collected from the fish assists in understanding and managing a sustainable fishery. This data may include stomach contents, age, sex and maturity of fish.
The A/OFRC uses the same procedure for each gill net set. A flag, labeled with the company’s name and contact information, is connected to an anchor that is attached to the end of the net by a bridle (rope connected to the float line and sink/lead line). This allows for easy recovery of the net and the ability for the net to be seen and avoided. Labeled nets also allow people to contact the A/OFRC in case of an emergency or for more information regarding specific net placements. When the net is placed in the water, you need to take into account its orientation to shore (i.e. perpendicular or parallel) and the water depth.
For each project there are different net lengths, mesh size, set times, numbers of sets, set locations (random vs. fixed), and set depths (nearshore; shallow: 2-5m; or deep: 5-15m). The methodology and data collection is dependent on the purpose of the project and the targeted species.