Age, growth and retrospective stock assessment of an economically extinct sparid fish, Polysteganus undulosus, from South Africa

J. R. Chale-Matsau, A. Govender, L. E. Beckley

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Age and growth of the endemic, reef-dwelling sparid, Polysteganus undulosus were determined by using archived otoliths collected in 1962 and 1963, before the fishery collapsed. Estimates of age ranged up to 20 years, but reproducibility of the age estimates was low because of stacking on the otolith margins in older fish. Validation of annual deposition of the opaque band indicated that active deposition occurred during late winter and spring. No difference in growth rate between the sexes was observed and the growth rate for the combined sexes was described by the following logistic equation: Lt = 942 mm TL/(1 + exp(-0.277 year-1 (t - 5.178 years))). The age-at-50% maturity was 8.8 years. A retrospective stock assessment revealed that, although in the early 1960s, the yield-per-recruit was optimal, the spawning biomass of P. undulosus was already at 25% of its unfished level. This study thus suggests that management strategies for slow-growing, long-lived, aggregating reef fishes should go beyond optimising yield alone and pay particular attention to the status of the spawning stock.

Original languageEnglish
Pages (from-to)87-92
Number of pages6
JournalFisheries Research
Volume51
Issue number1
DOIs
Publication statusPublished - 2001

Fingerprint

stock assessment
South Africa
otolith
spawning
reef
fish
otoliths
reefs
age at maturity
stacking
gender
logistics
fishery
reproducibility
winter
fisheries
biomass
Africa

Keywords

  • Age
  • Growth
  • Polysteganus undulosus
  • South Africa
  • Sparidae
  • Stock assessment

ASJC Scopus subject areas

  • Aquatic Science

Cite this

Age, growth and retrospective stock assessment of an economically extinct sparid fish, Polysteganus undulosus, from South Africa. / Chale-Matsau, J. R.; Govender, A.; Beckley, L. E.

In: Fisheries Research, Vol. 51, No. 1, 2001, p. 87-92.

Research output: Contribution to journalArticle

@article{c53fe742a0d54d4d972c000c0de1a0f7,
title = "Age, growth and retrospective stock assessment of an economically extinct sparid fish, Polysteganus undulosus, from South Africa",
abstract = "Age and growth of the endemic, reef-dwelling sparid, Polysteganus undulosus were determined by using archived otoliths collected in 1962 and 1963, before the fishery collapsed. Estimates of age ranged up to 20 years, but reproducibility of the age estimates was low because of stacking on the otolith margins in older fish. Validation of annual deposition of the opaque band indicated that active deposition occurred during late winter and spring. No difference in growth rate between the sexes was observed and the growth rate for the combined sexes was described by the following logistic equation: Lt = 942 mm TL/(1 + exp(-0.277 year-1 (t - 5.178 years))). The age-at-50{\%} maturity was 8.8 years. A retrospective stock assessment revealed that, although in the early 1960s, the yield-per-recruit was optimal, the spawning biomass of P. undulosus was already at 25{\%} of its unfished level. This study thus suggests that management strategies for slow-growing, long-lived, aggregating reef fishes should go beyond optimising yield alone and pay particular attention to the status of the spawning stock.",
keywords = "Age, Growth, Polysteganus undulosus, South Africa, Sparidae, Stock assessment",
author = "Chale-Matsau, {J. R.} and A. Govender and Beckley, {L. E.}",
year = "2001",
doi = "10.1016/S0165-7836(00)00235-6",
language = "English",
volume = "51",
pages = "87--92",
journal = "Fisheries Research",
issn = "0165-7836",
publisher = "Elsevier",
number = "1",

}

TY - JOUR

T1 - Age, growth and retrospective stock assessment of an economically extinct sparid fish, Polysteganus undulosus, from South Africa

AU - Chale-Matsau, J. R.

AU - Govender, A.

AU - Beckley, L. E.

PY - 2001

Y1 - 2001

N2 - Age and growth of the endemic, reef-dwelling sparid, Polysteganus undulosus were determined by using archived otoliths collected in 1962 and 1963, before the fishery collapsed. Estimates of age ranged up to 20 years, but reproducibility of the age estimates was low because of stacking on the otolith margins in older fish. Validation of annual deposition of the opaque band indicated that active deposition occurred during late winter and spring. No difference in growth rate between the sexes was observed and the growth rate for the combined sexes was described by the following logistic equation: Lt = 942 mm TL/(1 + exp(-0.277 year-1 (t - 5.178 years))). The age-at-50% maturity was 8.8 years. A retrospective stock assessment revealed that, although in the early 1960s, the yield-per-recruit was optimal, the spawning biomass of P. undulosus was already at 25% of its unfished level. This study thus suggests that management strategies for slow-growing, long-lived, aggregating reef fishes should go beyond optimising yield alone and pay particular attention to the status of the spawning stock.

AB - Age and growth of the endemic, reef-dwelling sparid, Polysteganus undulosus were determined by using archived otoliths collected in 1962 and 1963, before the fishery collapsed. Estimates of age ranged up to 20 years, but reproducibility of the age estimates was low because of stacking on the otolith margins in older fish. Validation of annual deposition of the opaque band indicated that active deposition occurred during late winter and spring. No difference in growth rate between the sexes was observed and the growth rate for the combined sexes was described by the following logistic equation: Lt = 942 mm TL/(1 + exp(-0.277 year-1 (t - 5.178 years))). The age-at-50% maturity was 8.8 years. A retrospective stock assessment revealed that, although in the early 1960s, the yield-per-recruit was optimal, the spawning biomass of P. undulosus was already at 25% of its unfished level. This study thus suggests that management strategies for slow-growing, long-lived, aggregating reef fishes should go beyond optimising yield alone and pay particular attention to the status of the spawning stock.

KW - Age

KW - Growth

KW - Polysteganus undulosus

KW - South Africa

KW - Sparidae

KW - Stock assessment

UR - http://www.scopus.com/inward/record.url?scp=0035081436&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0035081436&partnerID=8YFLogxK

U2 - 10.1016/S0165-7836(00)00235-6

DO - 10.1016/S0165-7836(00)00235-6

M3 - Article

AN - SCOPUS:0035081436

VL - 51

SP - 87

EP - 92

JO - Fisheries Research

JF - Fisheries Research

SN - 0165-7836

IS - 1

ER -