Water transport through Hecate Strait, British Columbia

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Abstract
The transport of water through Hecate Strait, British Columbia, is investigated to determine seasonal cycles and to find optimal surrogate series from which a long time series of along‐strait transport can be inferred and applied to fisheries and pollution problems. It is believed that the strength of a year‐class of cod in this Strait varies inversely with the transport in winter. Therefore, a good surrogate series is required, one that extends back in time to compare with fisheries records and will continue into the future to determine fluctuations in the population of these species. Current meters deployed for an 11‐month period in 1983–84 provide transport measurements. Subsurface pressure gauges were deployed at 10‐m depth at five sites around Hecate Strait for a two‐year period in 1982–84. The cross‐strait difference of pressures determined by two of these gauges (Beauchemin Channel and Atli Inlet) serves as the best transport indicator, with an average correlation coefficient r of 0.88. Longer, continuous series are provided by the records from float‐type sea‐level gauges at Prince Rupert (PR), Queen Charlotte City (QCC) and Bella Bella (BB). Local air pressure is added to these series to convert them to subsurface pressure. Time series of geostrophic and measured winds are also considered. Among these longer series, transport is predicted best by the combination (PR + BB)/2 ‐ QCC (r = 0.82), which represents a cross‐strait difference in subsurface pressure.