Presentation on theme: "Comparison of Selected Fish Species Inside and Outside Canada’s 200- mile Limit on the Grand Banks 1978-1994 Amy Williams MES Program, Memorial University."— Presentation transcript:
Disclaimer Due to the time constraints involved, the results presented here must be considered preliminary and care should be exercised in citing them.
Acknowledgements This work was carried out with support from the North Atlantic Arc project (U.S. National Science Foundation), Memorial University’s “Coasts Under Stress” program, and the Oceans Management Research Network (OMRN), Linking Science and Local Knowledge Node.
BACKGROUND In 1977 the Canadian Government extended its jurisdiction to 200 nautical miles, but some areas of the Grand Banks remained outside Canada’s jurisdiction. The question here is whether fish populations outside show different trends from those inside. The material in this presentation can be used to contribute to addressing the issue.
METHODS Data came from the ECNASAP database which contains spring and fall DFO scientific trawl data Analyses were carried out using Stata 7 analytical software. NAFO divisions 3KLNO on the Grand Banks c omprise the areas examined.
METHODS... Stations inside and outside were identified using the great circle distance equation to calculate the distance between the 16 headlands used to determine the original 200- mile limit and all survey stations. Stations with a distance of less than 200 nautical miles were coded as inside; all others were coded as outside.
METHODS... Species distribution, CPUE and mean size were determined for individual species in each year. Species distribution was determined by plotting the location of all stations where the species occurred overlain on a map showing all inside and outside stations.
METHODS... CPUE was calculated by dividing the total catch by the number of appropriate stations in each year. Mean size was calculated by dividing the total weight by the total number in each year. Each analysis was done for the full dataset and also for the spring and fall surveys separately, inside and outside.
ORGANIZATION For each species the presentation includes: –Distribution maps –Comparative (inside and outside) CPUE per year plots –Comparative (inside and outside) Size per year plots
Technical Notes... The following table lists the 21 species of interest that were analysed: –‘SAR’ refers to the 5 Atlantic Species-at-Risk. –‘Indicator’ refers to 9 species identified as representing a diversity of ecological types. –‘COSEWIC’ refers to 5 Atlantic species currently being considered by COSEWIC. –The others are species of commercial importance. Although only 21 species were analysed here, the general analytical software is available for application to any species in the database.
RESULTS To go directly to a species of interest in the presentation, use the PowerPoint Edit/Find command.
Grand Banks basemap – Stations Inside & Outside