Diving survey assessment of 1981 herring spawn in British Columbia / by C.W. Haegele. : Fs97-4/1638E-PDF

"Diving surveys were made for 172 km of herring spawn in 1981. There was complete diving survey coverage for the North Coast Division, nearly complete coverage for the Strait of Georgia Division, and partial coverage for the Queen Charlotte Islands, Central Coast, and West Coast of Vancouver Island divisions. Diving survey data was supplemented by Fishery Officer collected spawn survey data to produce final egg estimates for the 20 sections for which there was complete or partial diving survey coverage. Approximately 60% of the spawn produced by the 1981 spawning population was estimated in this manner. Fishery Officers generally underestimated the area of spawns, which resulted in underestimates of egg deposition. The distribution of eggs by substrate type was documented and regional differences in substrate utilization were found. The relationship of length of spawn to egg abundance was examined and 200 billion eggs per km of spawn were found to occur on gradually sloping beaches. On beaches of moderate to steep slope, 9.8 to 119.1 billion eggs per km of spawn were found"--Abstract, page iii.

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