Distribution, growth and transformation timing of larval Geotria australis in New Zealand |
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| Authors: | P R Tedd J R M Kelso |
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| Institution: | Ministry of Agriculture and Fisheries, Nelson, New Zealand;Department of Fisheries and Oceans, Great Lakes Laboratory for Fisheries and Aquatic Sciences, Sault Ste. Marie, Ontario, Canada |
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| Abstract: | Lamprey, Geotria australis, are widely distributed in New Zealand and are common in streams and rivers of the west coast of both islands, the southern tip of the North Island, the Banks Peninsula and the southern coast of the South Island. In fresh water, lamprey are found in association with all substrate types but are most commonly (> 50% of the sample sites) found in association with finer gravels. There is insufficient evidence to determine any change in historically abundant adult spawning migrations. Spawning, back calculated from larval growth rates, probably occurs late November-December, and emergence at 9.63 mm occurs in January. We estimate that, on average, ammocoetes grow 0.068 mm/day throughout the year, and metamorphose and emigrate to sea between January-May, 3.5 years after spawning at 101 mm (SD = 6.7). |
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| Keywords: | metamorphosis ammocoete lamprey distribution growth transformation |
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