Temperature preference and activity of juvenile cod in Broad Cove, Conception Bay, Newfoundland
Thesis (M.Sc.)--Memorial University of Newfoundland, 1989. Biology Bibliography: leaves 75-83. Field tracking studies conducted in Conception Bay, Newfoundland employing ultrasonic telemetry, determined the activity patterns of juvenile (3 year old) cod (Gadus morhua L.) on a daily and seasonal basi...
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ftmemorialunivdc:oai:collections.mun.ca:theses2/239190 2023-05-15T15:27:19+02:00 Temperature preference and activity of juvenile cod in Broad Cove, Conception Bay, Newfoundland Clark, Donald Stuart Memorial University of Newfoundland. Dept. of Biology Canada--Newfoundland and Labrador--Conception Bay 1989 xii, 86 leaves : ill. Image/jpeg; Application/pdf http://collections.mun.ca/cdm/ref/collection/theses2/id/239190 Eng eng Electronic Theses and Dissertations (10.10 MB) -- http://collections.mun.ca/PDFs/theses/Clark_DonaldStuart.pdf 76038579 http://collections.mun.ca/cdm/ref/collection/theses2/id/239190 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 Atlantic cod--Newfoundland and Labrador--Conception Bay--Effect of water temperature on Atlantic cod--Newfoundland and Labrador--Conception Bay--Migration Atlantic cod--Newfoundland and Labrador--Conception Bay--Seasonal distribution Text Electronic thesis or dissertation 1989 ftmemorialunivdc 2015-08-06T19:17:26Z Thesis (M.Sc.)--Memorial University of Newfoundland, 1989. Biology Bibliography: leaves 75-83. Field tracking studies conducted in Conception Bay, Newfoundland employing ultrasonic telemetry, determined the activity patterns of juvenile (3 year old) cod (Gadus morhua L.) on a daily and seasonal basis. In conjunction with the tracking study, the temperature preference of juvenile cod throughout the year was determined in the laboratory, and the influence of holding temperature on temperature preference was assessed. The results of the temperature preference studies were compared with water temperatures inhabited by juvenile cod in the field to assess the role that water temperature might play in mediating movement and activity. -- Juvenile cod exhibited seasonal variation in both temperature preference, and activity patterns. Temperature preference was highly correlated with seasonal changes in the temperature of the inshore waters inhabited by juvenile cod, both for fish acclimated to ambient temperature water, and those maintained at 10°C overwinter. This indicated that seasonal variation in temperature preference was initiated by factors other than changes in ambient water temperature. However, the temperature preference ol these two groups differed significantly, indicating that thermal history also influenced temperature preference. -- The tracking studies showed that during summer (May - September) juvenile cod were wide ranging, conducting a diel migration from deep cold water where they remained inactive diurnally, to shallow warm water where they actively fed nocturnally. In autumn (September - December) these fish were diurnally active within a restricted home range in shallow water over a sandy substrate. At night they were inactive and remained in a consistent night-resting site over a rocky substrate in close proximity to their diurnal home range. -- The summer diel migration may result in increased growth since the movement of juvenile cod into deep cool water during non-foraging hours would effect a lower metabolic rate, and hence lower maintenance costs. In September when the water column becomes isothermal their switch to a non-migratory diel activity pattern is consistent with what would be predicted on the basis of energetic efficiency. It is unclear what selective factors may be involved in the switch in September from nocturnal to diurnal activity. However the most parsimonious hypothesis is that juvenile cod time their activity to reduce predation risk. Thesis atlantic cod Gadus morhua Newfoundland studies University of Newfoundland Memorial University of Newfoundland: Digital Archives Initiative (DAI) Newfoundland Canada |
institution |
Open Polar |
collection |
Memorial University of Newfoundland: Digital Archives Initiative (DAI) |
op_collection_id |
ftmemorialunivdc |
language |
English |
topic |
Atlantic cod--Newfoundland and Labrador--Conception Bay--Effect of water temperature on Atlantic cod--Newfoundland and Labrador--Conception Bay--Migration Atlantic cod--Newfoundland and Labrador--Conception Bay--Seasonal distribution |
spellingShingle |
Atlantic cod--Newfoundland and Labrador--Conception Bay--Effect of water temperature on Atlantic cod--Newfoundland and Labrador--Conception Bay--Migration Atlantic cod--Newfoundland and Labrador--Conception Bay--Seasonal distribution Clark, Donald Stuart Temperature preference and activity of juvenile cod in Broad Cove, Conception Bay, Newfoundland |
topic_facet |
Atlantic cod--Newfoundland and Labrador--Conception Bay--Effect of water temperature on Atlantic cod--Newfoundland and Labrador--Conception Bay--Migration Atlantic cod--Newfoundland and Labrador--Conception Bay--Seasonal distribution |
description |
Thesis (M.Sc.)--Memorial University of Newfoundland, 1989. Biology Bibliography: leaves 75-83. Field tracking studies conducted in Conception Bay, Newfoundland employing ultrasonic telemetry, determined the activity patterns of juvenile (3 year old) cod (Gadus morhua L.) on a daily and seasonal basis. In conjunction with the tracking study, the temperature preference of juvenile cod throughout the year was determined in the laboratory, and the influence of holding temperature on temperature preference was assessed. The results of the temperature preference studies were compared with water temperatures inhabited by juvenile cod in the field to assess the role that water temperature might play in mediating movement and activity. -- Juvenile cod exhibited seasonal variation in both temperature preference, and activity patterns. Temperature preference was highly correlated with seasonal changes in the temperature of the inshore waters inhabited by juvenile cod, both for fish acclimated to ambient temperature water, and those maintained at 10°C overwinter. This indicated that seasonal variation in temperature preference was initiated by factors other than changes in ambient water temperature. However, the temperature preference ol these two groups differed significantly, indicating that thermal history also influenced temperature preference. -- The tracking studies showed that during summer (May - September) juvenile cod were wide ranging, conducting a diel migration from deep cold water where they remained inactive diurnally, to shallow warm water where they actively fed nocturnally. In autumn (September - December) these fish were diurnally active within a restricted home range in shallow water over a sandy substrate. At night they were inactive and remained in a consistent night-resting site over a rocky substrate in close proximity to their diurnal home range. -- The summer diel migration may result in increased growth since the movement of juvenile cod into deep cool water during non-foraging hours would effect a lower metabolic rate, and hence lower maintenance costs. In September when the water column becomes isothermal their switch to a non-migratory diel activity pattern is consistent with what would be predicted on the basis of energetic efficiency. It is unclear what selective factors may be involved in the switch in September from nocturnal to diurnal activity. However the most parsimonious hypothesis is that juvenile cod time their activity to reduce predation risk. |
author2 |
Memorial University of Newfoundland. Dept. of Biology |
format |
Thesis |
author |
Clark, Donald Stuart |
author_facet |
Clark, Donald Stuart |
author_sort |
Clark, Donald Stuart |
title |
Temperature preference and activity of juvenile cod in Broad Cove, Conception Bay, Newfoundland |
title_short |
Temperature preference and activity of juvenile cod in Broad Cove, Conception Bay, Newfoundland |
title_full |
Temperature preference and activity of juvenile cod in Broad Cove, Conception Bay, Newfoundland |
title_fullStr |
Temperature preference and activity of juvenile cod in Broad Cove, Conception Bay, Newfoundland |
title_full_unstemmed |
Temperature preference and activity of juvenile cod in Broad Cove, Conception Bay, Newfoundland |
title_sort |
temperature preference and activity of juvenile cod in broad cove, conception bay, newfoundland |
publishDate |
1989 |
url |
http://collections.mun.ca/cdm/ref/collection/theses2/id/239190 |
op_coverage |
Canada--Newfoundland and Labrador--Conception Bay |
geographic |
Newfoundland Canada |
geographic_facet |
Newfoundland Canada |
genre |
atlantic cod Gadus morhua Newfoundland studies University of Newfoundland |
genre_facet |
atlantic cod Gadus morhua Newfoundland studies University of Newfoundland |
op_source |
Paper copy kept in the Centre for Newfoundland Studies, Memorial University Libraries |
op_relation |
Electronic Theses and Dissertations (10.10 MB) -- http://collections.mun.ca/PDFs/theses/Clark_DonaldStuart.pdf 76038579 http://collections.mun.ca/cdm/ref/collection/theses2/id/239190 |
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_ |
1766357772222332928 |