. The Canadian field-naturalist. Natural history. 78 80 82 84 86 90 92 94 96 98 00 Year Figure 2. Twenty years of STRAP analyses for Atlantic Wolffish, Canadian waters. Solid line, filled circles: Engels trawl estimates. From 1978 to 1994 (16 years; , about two wolffish generations) there was no change in sampling method, and the decline is 87%. Dotted line, small dots: corrected estimates from Campelen trawls using the factor (see text), 1995-1999. Based on information provided by DFO in September 2000. Straight line shows the COSEWIC endangered criterion. turn out to be well-correla
. The Canadian field-naturalist. Natural history. 78 80 82 84 86 90 92 94 96 98 00 Year Figure 2. Twenty years of STRAP analyses for Atlantic Wolffish, Canadian waters. Solid line, filled circles: Engels trawl estimates. From 1978 to 1994 (16 years; , about two wolffish generations) there was no change in sampling method, and the decline is 87%. Dotted line, small dots: corrected estimates from Campelen trawls using the factor (see text), 1995-1999. Based on information provided by DFO in September 2000. Straight line shows the COSEWIC endangered criterion. turn out to be well-correlated (r = ) with the sim- ple metric we prefer, the number/tow. From 1978 tto 1993, the relative frequency of high survey catch rates off Newfoundland has declined, and low catch rates have been on the rise (Figure 3). In 1978, catches of five or less wolffish in a tow constituted less than 40% of all catches; by 1984 the frequency of low catches (<5) had risen to more than 70%, and in 1993 it was almost 90%. The increased frequency of low catch rates is another indication of declining population density. The trend to a declining mean size of fish, consid- ered together with the declining numbers, is yet another indication that wolffish populations are in trouble. These trends vary according to area, but all are down. The average size of Atlantic Wolffish from the Scotian Shelf and southern Gulf of St. Lawrence, while showing inter-annual variation, declined overall by 50% or more from the mid- 1980s to the present; the trend lines are essentially the same. Off Newfoundland, mean wolffish size declined from around a kilo in 1978 to near 700 gm in 1993. Fish of that size are probably not yet % Frequency 100 80 60 40 20 0 1978 100 80 ^ 60 T 40 20 0. 1984 .^^^^^^ 100 80 60 40 20 0. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly rese
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