Ecology and demographics of Pacific sand lance, Ammodytes hexapterus Pallas, in Lower Cook Inlet, Alaska
Thesis (M.Sc.)--Memorial University of Newfoundland, 2000. Biology Chapter 1 published in Journal of Fish Biology 54:1050-1068. Chapter 2 published in Journal of Experimental Marine Biology and Ecology 242: 245-258. Includes bibliographical references. Distinct sand lance populations occur within th...
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ftmemorialunivdc:oai:collections.mun.ca:theses3/8709 2023-05-15T17:23:32+02:00 Ecology and demographics of Pacific sand lance, Ammodytes hexapterus Pallas, in Lower Cook Inlet, Alaska Robards, Martin D. Memorial University of Newfoundland. Dept. of Biology United States--Alaska--Cook Inlet 2000 xv, [105] leaves in various foliations : graphs, maps Image/jpeg; Application/pdf http://collections.mun.ca/cdm/ref/collection/theses3/id/8709 eng eng Electronic Theses and Dissertations (10.95 MB) -- http://collections.mun.ca/PDFs/theses/Robards_MartinD.pdf a1477451 http://collections.mun.ca/cdm/ref/collection/theses3/id/8709 The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Paper copy kept in the Centre for Newfoundland Studies, Memorial University Libraries Ammodytes--Alaska--Cook Inlet Ammodytes--Ecology--Alaska--Cook Inlet Fish populations--Alaska--Cook Inlet Text Electronic thesis or dissertation 2000 ftmemorialunivdc 2015-08-06T19:17:40Z Thesis (M.Sc.)--Memorial University of Newfoundland, 2000. Biology Chapter 1 published in Journal of Fish Biology 54:1050-1068. Chapter 2 published in Journal of Experimental Marine Biology and Ecology 242: 245-258. Includes bibliographical references. Distinct sand lance populations occur within the relatively small geographic area of Lower Cook Inlet, Alaska. Marked meso-scale differences in abundance, growth, and mortality existed as a consequence of differing oceanographic regimes. Growth rate within populations (between years) was positively correlated with temperature. -- However, this did not extend to inter-population comparisons where differing growth rates were better correlated to marine productivity. Opaque otoliths form in juvenile sand lance during their first summer coinciding with their period of rapid growth. Subsequent opaque zones are deposited during spring, in conjunction with rapidly increasing water temperatures. Areal rather than radial descriptors of otolith size provide the best relation to sand lance length. A single linear regression was insufficient to describe this relationship with separate linear regressions needed for both juveniles and adults. No sexual dimorphism was observed for sand lance in length-at-weight (gonad-free) or length-at-age. Most sand lance reached maturity in their second year. Field observations and indices of maturity, gonad development, and ova-size distribution all indicated that sand lance spawn once each year. Males mature earlier in the season than females, but females (31 %) attain a higher gonadosomatic index than males (21 %). Sand lance spawned intertidally in late September and October on fine gravel/sandy beaches soon after the seasonal peak in water temperatures. Fecundity of females (93-199 mm) was proportional to length, ranging from 1,468 to 16,081 ova. Spawned eggs were 1.02 ± 0.08 mm in diameter, demersal, slightly adhesive, and deposited in the intertidal just below the waterline. Sand lance embryos developed over 67 days through periods of intertidal exposure and sub-freezing air temperatures. Mean dry-weight energy value of sand lance cycles seasonally, peaking in spring and early summer (20.91 klg-1 for males, 21.08 kJg-1 for females), and subsequently declining by about 25 % during late summer and fall (15.91 kJg-1 for males, 15.74 kJg-1 for females). Declines in energy density during late summer paralleled gonadal development, sand lance entering the winter with close to their minimum whole body energy content. Dry weight energy densities of juveniles increased from a minimum 16.67 kJg-1 to a maximum of 19.68 kJg-1 and are higher than adults in late summer. Thesis Newfoundland studies Alaska University of Newfoundland Memorial University of Newfoundland: Digital Archives Initiative (DAI) Pacific |
institution |
Open Polar |
collection |
Memorial University of Newfoundland: Digital Archives Initiative (DAI) |
op_collection_id |
ftmemorialunivdc |
language |
English |
topic |
Ammodytes--Alaska--Cook Inlet Ammodytes--Ecology--Alaska--Cook Inlet Fish populations--Alaska--Cook Inlet |
spellingShingle |
Ammodytes--Alaska--Cook Inlet Ammodytes--Ecology--Alaska--Cook Inlet Fish populations--Alaska--Cook Inlet Robards, Martin D. Ecology and demographics of Pacific sand lance, Ammodytes hexapterus Pallas, in Lower Cook Inlet, Alaska |
topic_facet |
Ammodytes--Alaska--Cook Inlet Ammodytes--Ecology--Alaska--Cook Inlet Fish populations--Alaska--Cook Inlet |
description |
Thesis (M.Sc.)--Memorial University of Newfoundland, 2000. Biology Chapter 1 published in Journal of Fish Biology 54:1050-1068. Chapter 2 published in Journal of Experimental Marine Biology and Ecology 242: 245-258. Includes bibliographical references. Distinct sand lance populations occur within the relatively small geographic area of Lower Cook Inlet, Alaska. Marked meso-scale differences in abundance, growth, and mortality existed as a consequence of differing oceanographic regimes. Growth rate within populations (between years) was positively correlated with temperature. -- However, this did not extend to inter-population comparisons where differing growth rates were better correlated to marine productivity. Opaque otoliths form in juvenile sand lance during their first summer coinciding with their period of rapid growth. Subsequent opaque zones are deposited during spring, in conjunction with rapidly increasing water temperatures. Areal rather than radial descriptors of otolith size provide the best relation to sand lance length. A single linear regression was insufficient to describe this relationship with separate linear regressions needed for both juveniles and adults. No sexual dimorphism was observed for sand lance in length-at-weight (gonad-free) or length-at-age. Most sand lance reached maturity in their second year. Field observations and indices of maturity, gonad development, and ova-size distribution all indicated that sand lance spawn once each year. Males mature earlier in the season than females, but females (31 %) attain a higher gonadosomatic index than males (21 %). Sand lance spawned intertidally in late September and October on fine gravel/sandy beaches soon after the seasonal peak in water temperatures. Fecundity of females (93-199 mm) was proportional to length, ranging from 1,468 to 16,081 ova. Spawned eggs were 1.02 ± 0.08 mm in diameter, demersal, slightly adhesive, and deposited in the intertidal just below the waterline. Sand lance embryos developed over 67 days through periods of intertidal exposure and sub-freezing air temperatures. Mean dry-weight energy value of sand lance cycles seasonally, peaking in spring and early summer (20.91 klg-1 for males, 21.08 kJg-1 for females), and subsequently declining by about 25 % during late summer and fall (15.91 kJg-1 for males, 15.74 kJg-1 for females). Declines in energy density during late summer paralleled gonadal development, sand lance entering the winter with close to their minimum whole body energy content. Dry weight energy densities of juveniles increased from a minimum 16.67 kJg-1 to a maximum of 19.68 kJg-1 and are higher than adults in late summer. |
author2 |
Memorial University of Newfoundland. Dept. of Biology |
format |
Thesis |
author |
Robards, Martin D. |
author_facet |
Robards, Martin D. |
author_sort |
Robards, Martin D. |
title |
Ecology and demographics of Pacific sand lance, Ammodytes hexapterus Pallas, in Lower Cook Inlet, Alaska |
title_short |
Ecology and demographics of Pacific sand lance, Ammodytes hexapterus Pallas, in Lower Cook Inlet, Alaska |
title_full |
Ecology and demographics of Pacific sand lance, Ammodytes hexapterus Pallas, in Lower Cook Inlet, Alaska |
title_fullStr |
Ecology and demographics of Pacific sand lance, Ammodytes hexapterus Pallas, in Lower Cook Inlet, Alaska |
title_full_unstemmed |
Ecology and demographics of Pacific sand lance, Ammodytes hexapterus Pallas, in Lower Cook Inlet, Alaska |
title_sort |
ecology and demographics of pacific sand lance, ammodytes hexapterus pallas, in lower cook inlet, alaska |
publishDate |
2000 |
url |
http://collections.mun.ca/cdm/ref/collection/theses3/id/8709 |
op_coverage |
United States--Alaska--Cook Inlet |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Newfoundland studies Alaska University of Newfoundland |
genre_facet |
Newfoundland studies Alaska University of Newfoundland |
op_source |
Paper copy kept in the Centre for Newfoundland Studies, Memorial University Libraries |
op_relation |
Electronic Theses and Dissertations (10.95 MB) -- http://collections.mun.ca/PDFs/theses/Robards_MartinD.pdf a1477451 http://collections.mun.ca/cdm/ref/collection/theses3/id/8709 |
op_rights |
The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. |
_version_ |
1766113039892873216 |