Analysis of stomach contents and predator-prey relations of 168 swordfish from the western North Atlantic Ocean is presented. The predominant food of swordfish is squid (82 % by frequency of occurrence) followed by fish (53 % ) consisting primarily of gadids, scombrids, butterfish, bluefish, and sand lance. Average food volume in stomachs is 1 % of average body weight. Estimates of daily ration range from 0.94 % to 1.6 % of average body weight, with yearly consumption ranging from 3.4 to 5.8 times average body weight per year. The prey biomass consumed by the swordfish population in the Georges Bank area is estimated to range from 2,100 to 11,000 mt over a residency time of 5 mo.
Results of an ongoing Cooperative Shark Tagging Program conducted by the National
Marine Fisheries Service (USA) are described. In all, 2459 shortfin mako sharks
(Isurus oxyrinchus) were tagged off the Atlantic coast of North America and in the
Gulf of Mexico in the 28-year period between 1962 and 1989. The sharks were
tagged by volunteer fishers, scientists aboard research vessels, and US Foreign
Fisheries Observers on foreign vessels fishing in US waters. Altogether, 231 recaptures
(9.4% of releases) of these tagged sharks have been reported by fishers from 16 countries.
The maximum time at liberty is 8.2 years, and the maximum straight-line distance between
tag and recapture localities is 2452 nautical miles. One tag was recovered from the
European side of the Mid-Atlantic Ridge. Mako shark distribution and migratory patterns
in relation to water temperature are discussed for the western North Atlantic.
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