Importance of biological parameters in assessing the status of Delphinus delphis
Short-beaked common dolphins Delphinus delphis in the eastern North Atlantic (ENA) are subject to mortality due to entanglement in various types of fishing gear. However, for this region, there is no population-level information available on trends in abundance, (incidental) mortality rates or even...
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INTER-RESEARCH
2009
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ftucl:oai:eprints.ucl.ac.uk.OAI2:1521825 2023-12-24T10:23:03+01:00 Importance of biological parameters in assessing the status of Delphinus delphis Murphy, S Winship, A Dabin, W Jepson, PD Deaville, R Reid, RJ Spurrier, C Rogan, E Lopez, A Gonzalez, AF Read, FL Addink, M Silva, M Ridoux, V Learmonth, JA Pierce, GJ Northridge, SP 2009-08-19 text https://discovery.ucl.ac.uk/id/eprint/1521825/1/Jepson%20Murphy%20et%20al.%202009%20MEPS.pdf https://discovery.ucl.ac.uk/id/eprint/1521825/ eng eng INTER-RESEARCH https://discovery.ucl.ac.uk/id/eprint/1521825/1/Jepson%20Murphy%20et%20al.%202009%20MEPS.pdf https://discovery.ucl.ac.uk/id/eprint/1521825/ open Marine Ecology Progress Series , 388 pp. 273-291. (2009) Science & Technology Life Sciences & Biomedicine Physical Sciences Ecology Marine & Freshwater Biology Oceanography Environmental Sciences & Ecology Common dolphin Delphinus delphis Life history Density-dependent Control group Eastern North Atlantic COMMON DOLPHINS DELPHINUS EASTERN TROPICAL PACIFIC BOTTLE-NOSED DOLPHINS PORPOISES PHOCOENA-PHOCOENA NORTH-ATLANTIC TURSIOPS-TRUNCATUS LIFE-HISTORY POLYCHLORINATED-BIPHENYLS REPRODUCTIVE SUCCESS STENELLA-ATTENUATA Article 2009 ftucl 2023-11-27T13:07:34Z Short-beaked common dolphins Delphinus delphis in the eastern North Atlantic (ENA) are subject to mortality due to entanglement in various types of fishing gear. However, for this region, there is no population-level information available on trends in abundance, (incidental) mortality rates or even the actual distributional range. Working under the assumption that only 1 population exists in ENA waters, the current study presents basic life history data and investigates whether biological information obtained from postmortem data is, in itself, useful for managing this population. Life history parameters were estimated by analysing postmortem data obtained over a 16 yr period by UK, Irish, French, Galician (northwest Spain) and Portuguese stranding and bycatch observer programmes. An annual pregnancy rate of 26%, a calving interval of 3.79 yr, an average age attained at sexual maturity of 8.22 yr and an average length at sexual maturity of 188 cm were determined. With respect to the findings based solely on mortality data, significance testing failed to detect differences that could be construed as evidence of the population exhibiting what might be density-dependent compensatory responses. The low annual pregnancy rate reported throughout the sampling period may suggest either that the level of anthropogenic mortality did not cause a substantial population level decline, or a prey base declining at approximately the same rate as the dolphin population. However, this approach alone does not facilitate an assessment of the current state of the D. delphis population in the ENA. Population abundance estimates, trends in abundance and knowledge of factors that affect the dynamics of the population, such as annual mortality rates in fisheries, temporal variations in prey abundance and effects of contaminants on reproductive activity, are required not only to set management objectives, but also to give context to cross-sectional life history information. Article in Journal/Newspaper North Atlantic Phocoena phocoena University College London: UCL Discovery Pacific |
institution |
Open Polar |
collection |
University College London: UCL Discovery |
op_collection_id |
ftucl |
language |
English |
topic |
Science & Technology Life Sciences & Biomedicine Physical Sciences Ecology Marine & Freshwater Biology Oceanography Environmental Sciences & Ecology Common dolphin Delphinus delphis Life history Density-dependent Control group Eastern North Atlantic COMMON DOLPHINS DELPHINUS EASTERN TROPICAL PACIFIC BOTTLE-NOSED DOLPHINS PORPOISES PHOCOENA-PHOCOENA NORTH-ATLANTIC TURSIOPS-TRUNCATUS LIFE-HISTORY POLYCHLORINATED-BIPHENYLS REPRODUCTIVE SUCCESS STENELLA-ATTENUATA |
spellingShingle |
Science & Technology Life Sciences & Biomedicine Physical Sciences Ecology Marine & Freshwater Biology Oceanography Environmental Sciences & Ecology Common dolphin Delphinus delphis Life history Density-dependent Control group Eastern North Atlantic COMMON DOLPHINS DELPHINUS EASTERN TROPICAL PACIFIC BOTTLE-NOSED DOLPHINS PORPOISES PHOCOENA-PHOCOENA NORTH-ATLANTIC TURSIOPS-TRUNCATUS LIFE-HISTORY POLYCHLORINATED-BIPHENYLS REPRODUCTIVE SUCCESS STENELLA-ATTENUATA Murphy, S Winship, A Dabin, W Jepson, PD Deaville, R Reid, RJ Spurrier, C Rogan, E Lopez, A Gonzalez, AF Read, FL Addink, M Silva, M Ridoux, V Learmonth, JA Pierce, GJ Northridge, SP Importance of biological parameters in assessing the status of Delphinus delphis |
topic_facet |
Science & Technology Life Sciences & Biomedicine Physical Sciences Ecology Marine & Freshwater Biology Oceanography Environmental Sciences & Ecology Common dolphin Delphinus delphis Life history Density-dependent Control group Eastern North Atlantic COMMON DOLPHINS DELPHINUS EASTERN TROPICAL PACIFIC BOTTLE-NOSED DOLPHINS PORPOISES PHOCOENA-PHOCOENA NORTH-ATLANTIC TURSIOPS-TRUNCATUS LIFE-HISTORY POLYCHLORINATED-BIPHENYLS REPRODUCTIVE SUCCESS STENELLA-ATTENUATA |
description |
Short-beaked common dolphins Delphinus delphis in the eastern North Atlantic (ENA) are subject to mortality due to entanglement in various types of fishing gear. However, for this region, there is no population-level information available on trends in abundance, (incidental) mortality rates or even the actual distributional range. Working under the assumption that only 1 population exists in ENA waters, the current study presents basic life history data and investigates whether biological information obtained from postmortem data is, in itself, useful for managing this population. Life history parameters were estimated by analysing postmortem data obtained over a 16 yr period by UK, Irish, French, Galician (northwest Spain) and Portuguese stranding and bycatch observer programmes. An annual pregnancy rate of 26%, a calving interval of 3.79 yr, an average age attained at sexual maturity of 8.22 yr and an average length at sexual maturity of 188 cm were determined. With respect to the findings based solely on mortality data, significance testing failed to detect differences that could be construed as evidence of the population exhibiting what might be density-dependent compensatory responses. The low annual pregnancy rate reported throughout the sampling period may suggest either that the level of anthropogenic mortality did not cause a substantial population level decline, or a prey base declining at approximately the same rate as the dolphin population. However, this approach alone does not facilitate an assessment of the current state of the D. delphis population in the ENA. Population abundance estimates, trends in abundance and knowledge of factors that affect the dynamics of the population, such as annual mortality rates in fisheries, temporal variations in prey abundance and effects of contaminants on reproductive activity, are required not only to set management objectives, but also to give context to cross-sectional life history information. |
format |
Article in Journal/Newspaper |
author |
Murphy, S Winship, A Dabin, W Jepson, PD Deaville, R Reid, RJ Spurrier, C Rogan, E Lopez, A Gonzalez, AF Read, FL Addink, M Silva, M Ridoux, V Learmonth, JA Pierce, GJ Northridge, SP |
author_facet |
Murphy, S Winship, A Dabin, W Jepson, PD Deaville, R Reid, RJ Spurrier, C Rogan, E Lopez, A Gonzalez, AF Read, FL Addink, M Silva, M Ridoux, V Learmonth, JA Pierce, GJ Northridge, SP |
author_sort |
Murphy, S |
title |
Importance of biological parameters in assessing the status of Delphinus delphis |
title_short |
Importance of biological parameters in assessing the status of Delphinus delphis |
title_full |
Importance of biological parameters in assessing the status of Delphinus delphis |
title_fullStr |
Importance of biological parameters in assessing the status of Delphinus delphis |
title_full_unstemmed |
Importance of biological parameters in assessing the status of Delphinus delphis |
title_sort |
importance of biological parameters in assessing the status of delphinus delphis |
publisher |
INTER-RESEARCH |
publishDate |
2009 |
url |
https://discovery.ucl.ac.uk/id/eprint/1521825/1/Jepson%20Murphy%20et%20al.%202009%20MEPS.pdf https://discovery.ucl.ac.uk/id/eprint/1521825/ |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
North Atlantic Phocoena phocoena |
genre_facet |
North Atlantic Phocoena phocoena |
op_source |
Marine Ecology Progress Series , 388 pp. 273-291. (2009) |
op_relation |
https://discovery.ucl.ac.uk/id/eprint/1521825/1/Jepson%20Murphy%20et%20al.%202009%20MEPS.pdf https://discovery.ucl.ac.uk/id/eprint/1521825/ |
op_rights |
open |
_version_ |
1786196732890054656 |