Migration, distribution and population (stock) structure of shallow-water hake (Merluccius capensis) in the Benguela Current Large Marine Ecosystem inferred using a geostatistical population model

Teunis Jansen, Kasper Kristensen, Paulus Inekela Kainge, Deon Durholtz, Tore Strømme, Uffe Høgsbro Thygesen, Margit R. Wilhelm, John Kathena, Tracey P. Fairweather, Sarah Paulus, Henrik Degel, Marek R. Lipinski, Jan Beyer

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Shallow-water hake (Merluccius capensis) is of considerable ecological and economic importance in the Benguela Current Large Marine Ecosystem in South Africa and Namibia. Optimal management of the resource is currently constrained by the limited understanding of migration patterns and population (stock) structure. We combined data from multiple demersal trawl surveys from the entire distribution area to estimate growth rate, mortality and spatial and temporal patterns of M. capensis. Analyses were conducted using the geostatistical model GeoPop. The complexity of the model and the amount of data required a new level of soft- and hardware performance. This was achieved by utilizing Template Model Builder and high-end computational hardware (Amazon Elastic Compute Cloud, EC2). The data and the model enabled us to follow the distribution and infer movements of M. capensis from the recruitment/nursery areas, through the juvenile phase and the adults' migration to the spawning areas outside/upstream of the nursery areas. This revealed some previously unknown migration patterns and indicated natal homing and the existence of three primary population components in the region, namely the Walvis (central and northern Namibia), the Orange (Southern Namibia-Northern SA) and the Agulhas (Southern part of SA) components. Our results also indicated substantial regional differences in mortality. We recommend that fisheries assessment, advice and management take consideration of these aspects of the distribution and population (stock) structure of M. capensis in the Benguela Current Large Marine Ecosystem.
Original languageEnglish
JournalFisheries Research
Volume179
Pages (from-to)156-167
ISSN0165-7836
DOIs
Publication statusPublished - 2016

Keywords

  • Aquatic Science
  • Benguela Current
  • Demersal trawl
  • Geostatistics
  • Hake
  • LGC
  • Merluccius capensis
  • Migration
  • Mortality
  • Namibia
  • Natal homing
  • Population structure
  • South Africa
  • Template Model Builder
  • TMB
  • Trans-boundary

Cite this

@article{a605236ef54a4c409974b94c43ea5227,
title = "Migration, distribution and population (stock) structure of shallow-water hake (Merluccius capensis) in the Benguela Current Large Marine Ecosystem inferred using a geostatistical population model",
abstract = "Shallow-water hake (Merluccius capensis) is of considerable ecological and economic importance in the Benguela Current Large Marine Ecosystem in South Africa and Namibia. Optimal management of the resource is currently constrained by the limited understanding of migration patterns and population (stock) structure. We combined data from multiple demersal trawl surveys from the entire distribution area to estimate growth rate, mortality and spatial and temporal patterns of M. capensis. Analyses were conducted using the geostatistical model GeoPop. The complexity of the model and the amount of data required a new level of soft- and hardware performance. This was achieved by utilizing Template Model Builder and high-end computational hardware (Amazon Elastic Compute Cloud, EC2). The data and the model enabled us to follow the distribution and infer movements of M. capensis from the recruitment/nursery areas, through the juvenile phase and the adults' migration to the spawning areas outside/upstream of the nursery areas. This revealed some previously unknown migration patterns and indicated natal homing and the existence of three primary population components in the region, namely the Walvis (central and northern Namibia), the Orange (Southern Namibia-Northern SA) and the Agulhas (Southern part of SA) components. Our results also indicated substantial regional differences in mortality. We recommend that fisheries assessment, advice and management take consideration of these aspects of the distribution and population (stock) structure of M. capensis in the Benguela Current Large Marine Ecosystem.",
keywords = "Aquatic Science, Benguela Current, Demersal trawl, Geostatistics, Hake, LGC, Merluccius capensis, Migration, Mortality, Namibia, Natal homing, Population structure, South Africa, Template Model Builder, TMB, Trans-boundary",
author = "Teunis Jansen and Kasper Kristensen and Kainge, {Paulus Inekela} and Deon Durholtz and Tore Str{\o}mme and Thygesen, {Uffe H{\o}gsbro} and Wilhelm, {Margit R.} and John Kathena and Fairweather, {Tracey P.} and Sarah Paulus and Henrik Degel and Lipinski, {Marek R.} and Jan Beyer",
year = "2016",
doi = "10.1016/j.fishres.2016.02.026",
language = "English",
volume = "179",
pages = "156--167",
journal = "Fisheries Research",
issn = "0165-7836",
publisher = "Elsevier",

}

Migration, distribution and population (stock) structure of shallow-water hake (Merluccius capensis) in the Benguela Current Large Marine Ecosystem inferred using a geostatistical population model. / Jansen, Teunis; Kristensen, Kasper; Kainge, Paulus Inekela; Durholtz, Deon; Strømme, Tore; Thygesen, Uffe Høgsbro; Wilhelm, Margit R.; Kathena, John; Fairweather, Tracey P.; Paulus, Sarah; Degel, Henrik; Lipinski, Marek R.; Beyer, Jan.

In: Fisheries Research, Vol. 179, 2016, p. 156-167.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Migration, distribution and population (stock) structure of shallow-water hake (Merluccius capensis) in the Benguela Current Large Marine Ecosystem inferred using a geostatistical population model

AU - Jansen, Teunis

AU - Kristensen, Kasper

AU - Kainge, Paulus Inekela

AU - Durholtz, Deon

AU - Strømme, Tore

AU - Thygesen, Uffe Høgsbro

AU - Wilhelm, Margit R.

AU - Kathena, John

AU - Fairweather, Tracey P.

AU - Paulus, Sarah

AU - Degel, Henrik

AU - Lipinski, Marek R.

AU - Beyer, Jan

PY - 2016

Y1 - 2016

N2 - Shallow-water hake (Merluccius capensis) is of considerable ecological and economic importance in the Benguela Current Large Marine Ecosystem in South Africa and Namibia. Optimal management of the resource is currently constrained by the limited understanding of migration patterns and population (stock) structure. We combined data from multiple demersal trawl surveys from the entire distribution area to estimate growth rate, mortality and spatial and temporal patterns of M. capensis. Analyses were conducted using the geostatistical model GeoPop. The complexity of the model and the amount of data required a new level of soft- and hardware performance. This was achieved by utilizing Template Model Builder and high-end computational hardware (Amazon Elastic Compute Cloud, EC2). The data and the model enabled us to follow the distribution and infer movements of M. capensis from the recruitment/nursery areas, through the juvenile phase and the adults' migration to the spawning areas outside/upstream of the nursery areas. This revealed some previously unknown migration patterns and indicated natal homing and the existence of three primary population components in the region, namely the Walvis (central and northern Namibia), the Orange (Southern Namibia-Northern SA) and the Agulhas (Southern part of SA) components. Our results also indicated substantial regional differences in mortality. We recommend that fisheries assessment, advice and management take consideration of these aspects of the distribution and population (stock) structure of M. capensis in the Benguela Current Large Marine Ecosystem.

AB - Shallow-water hake (Merluccius capensis) is of considerable ecological and economic importance in the Benguela Current Large Marine Ecosystem in South Africa and Namibia. Optimal management of the resource is currently constrained by the limited understanding of migration patterns and population (stock) structure. We combined data from multiple demersal trawl surveys from the entire distribution area to estimate growth rate, mortality and spatial and temporal patterns of M. capensis. Analyses were conducted using the geostatistical model GeoPop. The complexity of the model and the amount of data required a new level of soft- and hardware performance. This was achieved by utilizing Template Model Builder and high-end computational hardware (Amazon Elastic Compute Cloud, EC2). The data and the model enabled us to follow the distribution and infer movements of M. capensis from the recruitment/nursery areas, through the juvenile phase and the adults' migration to the spawning areas outside/upstream of the nursery areas. This revealed some previously unknown migration patterns and indicated natal homing and the existence of three primary population components in the region, namely the Walvis (central and northern Namibia), the Orange (Southern Namibia-Northern SA) and the Agulhas (Southern part of SA) components. Our results also indicated substantial regional differences in mortality. We recommend that fisheries assessment, advice and management take consideration of these aspects of the distribution and population (stock) structure of M. capensis in the Benguela Current Large Marine Ecosystem.

KW - Aquatic Science

KW - Benguela Current

KW - Demersal trawl

KW - Geostatistics

KW - Hake

KW - LGC

KW - Merluccius capensis

KW - Migration

KW - Mortality

KW - Namibia

KW - Natal homing

KW - Population structure

KW - South Africa

KW - Template Model Builder

KW - TMB

KW - Trans-boundary

U2 - 10.1016/j.fishres.2016.02.026

DO - 10.1016/j.fishres.2016.02.026

M3 - Journal article

VL - 179

SP - 156

EP - 167

JO - Fisheries Research

JF - Fisheries Research

SN - 0165-7836

ER -