Tools to examine population maturity and diet of Nephrops norvegicus on Irish fishing grounds

The research presented within this thesis describes investigations on maturity and feeding ecology of Nephrops across some Irish and Scottish grounds in the Northeast Atlantic Ocean. This thesis aimed to address the gaps and ambiguities concerning the feeding ecology and the need for improvement in...

Full description

Bibliographic Details
Main Author: da Silva Santana, Cesar Augusto
Other Authors: Power, Anne Marie, Irish Research Council, College of Science and Engineering, National University of Ireland Galway
Format: Thesis
Language:unknown
Published: NUI Galway 2021
Subjects:
SIA
POM
CDA
Online Access:http://hdl.handle.net/10379/16844
id ftnuigalway:oai:aran.library.nuigalway.ie/:10379/16844
record_format openpolar
spelling ftnuigalway:oai:aran.library.nuigalway.ie/:10379/16844 2023-06-11T04:15:18+02:00 Tools to examine population maturity and diet of Nephrops norvegicus on Irish fishing grounds da Silva Santana, Cesar Augusto Power, Anne Marie Irish Research Council College of Science and Engineering, National University of Ireland Galway 2021-01-11 http://hdl.handle.net/10379/16844 unknown NUI Galway http://hdl.handle.net/10379/16844 Attribution-NonCommercial-NoDerivs 3.0 Ireland https://creativecommons.org/licenses/by-nc-nd/3.0/ie/ Nephrops Norway lobster diet SIA stable isotopes POM Maturity size at maturity density morphometry CDA discrimination Zoology Natural Sciences Science and Engineering Thesis 2021 ftnuigalway 2023-05-28T18:06:44Z The research presented within this thesis describes investigations on maturity and feeding ecology of Nephrops across some Irish and Scottish grounds in the Northeast Atlantic Ocean. This thesis aimed to address the gaps and ambiguities concerning the feeding ecology and the need for improvement in techniques related to the estimation of the size at maturity. The major objective of this study was to gain insights on the feeding ecology of Nephrops, as well as about the size at maturity of this species and, in particular, the effects of density-dependent processes on size at maturity and morphometry in Nephrops populations. These objectives were addressed using stable isotope analysis (SIA) in a Bayesian approach, multivariate morphometric techniques and a new methodology, developed in this study: theoretical size at the onset of maturity (TSOM), for estimation of the size at the onset of maturity of female Nephrops, which might be particularly useful in data poor situations or for large-scale studies including macro-ecological comparisons. Our estimates indicated that almost half the diet (47%) was made up of suspended particulate organic matter alone. Fish was another important item in the diet, with plankton and invertebrate sources coming much lower down in dietary importance. Significantly more suspension feeding was observed in small or medium sized individuals than large ones in both sexes. However, there were no sex-related patterns, despite females being restricted to burrows for part of the analysis period. Onset of maturity using TSOM varied from 18.4-33.7 mm carapace length for the Irish grounds. These estimates showed a significant negative linear relationship (R2 = 0.60) with population density at all grounds / years, and a significant positive linear relationship with average size in females (both mature and immature, R2 = 0.84). L50 was linked to the new TSOM metric by a significant positive linear relationship (R2 = 0.40). This set of linear relationships ultimately allowed TSOM and L50 to be ... Thesis Northeast Atlantic National University of Ireland (NUI), Galway: ARAN Norway Burrows ENVELOPE(163.650,163.650,-74.300,-74.300)
institution Open Polar
collection National University of Ireland (NUI), Galway: ARAN
op_collection_id ftnuigalway
language unknown
topic Nephrops
Norway lobster
diet
SIA
stable isotopes
POM
Maturity
size at maturity
density
morphometry
CDA
discrimination
Zoology
Natural Sciences
Science and Engineering
spellingShingle Nephrops
Norway lobster
diet
SIA
stable isotopes
POM
Maturity
size at maturity
density
morphometry
CDA
discrimination
Zoology
Natural Sciences
Science and Engineering
da Silva Santana, Cesar Augusto
Tools to examine population maturity and diet of Nephrops norvegicus on Irish fishing grounds
topic_facet Nephrops
Norway lobster
diet
SIA
stable isotopes
POM
Maturity
size at maturity
density
morphometry
CDA
discrimination
Zoology
Natural Sciences
Science and Engineering
description The research presented within this thesis describes investigations on maturity and feeding ecology of Nephrops across some Irish and Scottish grounds in the Northeast Atlantic Ocean. This thesis aimed to address the gaps and ambiguities concerning the feeding ecology and the need for improvement in techniques related to the estimation of the size at maturity. The major objective of this study was to gain insights on the feeding ecology of Nephrops, as well as about the size at maturity of this species and, in particular, the effects of density-dependent processes on size at maturity and morphometry in Nephrops populations. These objectives were addressed using stable isotope analysis (SIA) in a Bayesian approach, multivariate morphometric techniques and a new methodology, developed in this study: theoretical size at the onset of maturity (TSOM), for estimation of the size at the onset of maturity of female Nephrops, which might be particularly useful in data poor situations or for large-scale studies including macro-ecological comparisons. Our estimates indicated that almost half the diet (47%) was made up of suspended particulate organic matter alone. Fish was another important item in the diet, with plankton and invertebrate sources coming much lower down in dietary importance. Significantly more suspension feeding was observed in small or medium sized individuals than large ones in both sexes. However, there were no sex-related patterns, despite females being restricted to burrows for part of the analysis period. Onset of maturity using TSOM varied from 18.4-33.7 mm carapace length for the Irish grounds. These estimates showed a significant negative linear relationship (R2 = 0.60) with population density at all grounds / years, and a significant positive linear relationship with average size in females (both mature and immature, R2 = 0.84). L50 was linked to the new TSOM metric by a significant positive linear relationship (R2 = 0.40). This set of linear relationships ultimately allowed TSOM and L50 to be ...
author2 Power, Anne Marie
Irish Research Council
College of Science and Engineering, National University of Ireland Galway
format Thesis
author da Silva Santana, Cesar Augusto
author_facet da Silva Santana, Cesar Augusto
author_sort da Silva Santana, Cesar Augusto
title Tools to examine population maturity and diet of Nephrops norvegicus on Irish fishing grounds
title_short Tools to examine population maturity and diet of Nephrops norvegicus on Irish fishing grounds
title_full Tools to examine population maturity and diet of Nephrops norvegicus on Irish fishing grounds
title_fullStr Tools to examine population maturity and diet of Nephrops norvegicus on Irish fishing grounds
title_full_unstemmed Tools to examine population maturity and diet of Nephrops norvegicus on Irish fishing grounds
title_sort tools to examine population maturity and diet of nephrops norvegicus on irish fishing grounds
publisher NUI Galway
publishDate 2021
url http://hdl.handle.net/10379/16844
long_lat ENVELOPE(163.650,163.650,-74.300,-74.300)
geographic Norway
Burrows
geographic_facet Norway
Burrows
genre Northeast Atlantic
genre_facet Northeast Atlantic
op_relation http://hdl.handle.net/10379/16844
op_rights Attribution-NonCommercial-NoDerivs 3.0 Ireland
https://creativecommons.org/licenses/by-nc-nd/3.0/ie/
_version_ 1768371999557550080