Research@StAndrews
 
The University of St Andrews

Research@StAndrews:FullText >
Biology (School of) >
Biology >
Biology Theses >

Please use this identifier to cite or link to this item: http://hdl.handle.net/10023/2772
This item has been viewed 28 times in the last year. View Statistics

Files in This Item:

File Description SizeFormat
ElizabethBrownPhDThesisV2.pdf29.7 MBAdobe PDFView/Open
ElizabethBrownPhDThesisV1.pdf12.22 MBAdobe PDFView/Open
Title: Growth processes in the two Scottish populations of powan, Coregonus lavaretus (L.) (Eateleosteia, Salmonidae)
Authors: Brown, Elizabeth A. R.
Issue Date: 1990
Abstract: The powan, Coregonus lavaretus (L.) is endemic to only two British waters, Loch Lomond and Loch Eck, Scotland. This thesis describes the seasonal and longer term growth processes of the two populations, concentrating on growth in length back-calculated from scales, factors affecting recruitment and mortality, reproductive cycles, and seasonal deposition and mobilisation of storage products, particularly lipid. The interrelationships of these cycles is discussed. The populations differ in their diet and duration of feeding, and it is shown that most of the inter-population differences in seasonal cycles of growth relate to these feeding differences. The Loch Eck population is the more variable. In addition to adult and immature powan, a third category is identified, termed adolescents. These are fish which are entering their first reproductive cycle. Immature and adolescent fish are analysed separately and compared with the adults. There are some differences in seasonal cycles between the juveniles and adults, mainly in relation to the presence or absence of the reproductive cycle. A preliminary histological study of the ovaries of adolescent females is carried out. Comparison of historical data with the results of the present study shows that there has been little change in the Loch Lomond powan in the past 200 years. Both lochs are coming under increasing human pressure, and conservational measures urgently need to be taken if the powan populations are to survive.
URI: http://hdl.handle.net/10023/2772
Other Identifiers: uk.bl.ethos.549164
Type: Thesis
Publisher: University of St Andrews
Appears in Collections:Biology Theses



This item is protected by original copyright

This item is licensed under a Creative Commons License
Creative Commons

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

 

DSpace Software Copyright © 2002-2012  Duraspace - Feedback
For help contact: Digital-Repository@st-andrews.ac.uk | Copyright for this page belongs to St Andrews University Library | Terms and Conditions (Cookies)