Multi-decadal scale variability in the eastern Baltic cod fishery 1550-1860

Evidence and causes

Brian R. MacKenzie, Maibritt Bager, Henn Ojaveer, Kenneth Awebro, Ulla Heino, Poul Holm, Aadu Must

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Identification of periods of high and low cod production, and the reasons for these periods, can increase understanding of variability in populations and ecosystems. In this study we investigate the multi-decadal and multi-century scale variations in the cod population in the eastern Baltic Sea (ICES Subdivisions 25-32). Analytically derived estimates of biomass are available since 1966. These estimates show that biomass increased in the late 1970s-early 1980s, but decreased nearly 10-fold until the early 1990s and is still well below the long-term average. Prior to 1966 the biomass of cod is unknown, as is the relative role of fishing, climate variability/regimes, eutrophication and reduction of marine mammal predator populations. We have begun to investigate whether historical fisheries information (landings, effort, distribution) from before the 1880s is available in Baltic archives and museums, and to what extent this information can be used to interpret variations in this population. We have located fisheries data for different parts of the Baltic for different time periods since the 1550s and have interpreted the findings using current process knowledge of oceanographic mechanisms affecting cod reproduction and ecology in the Baltic Sea. The recovered data show that the Baltic ecosystem was able to support modest-large cod populations even though it was oligotrophic and contained large populations of cod predators (e.g., marine mammals). Current ecosystem management policy in the Baltic as developed and implemented by organisations such as the International Council for the Exploration of the Sea (ICES), the Baltic Marine Environment Protection Commission (HELCOM), the nine coastal countries and the European Union includes recovery of the cod population, a reduction in nutrient loading and measures to promote recovery of seal and harbour porpoise populations. If these policies are successful, the role of predatory fish in the future Baltic could again be substantial and comparable to that which we show existed 450 years ago. However, such a scenario will also require a major reduction in cod fishing mortality and suitable hydrographic conditions which promote successful cod reproduction. Historical ecology investigations in the Baltic can contribute to scientifically based fishery and ecosystem management and recovery plans. © 2007 Elsevier B.V. All rights reserved
Original languageEnglish
JournalFisheries Research
Volume87
Issue number2-3
Pages (from-to)106-119
Number of pages14
ISSN0165-7836
DOIs
Publication statusPublished - 2007

Keywords

  • Baltic Sea
  • Cod
  • Historical ecology
  • Fisheries
  • Ecosystem
  • Management

Cite this

MacKenzie, B. R., Bager, M., Ojaveer, H., Awebro, K., Heino, U., Holm, P., & Must, A. (2007). Multi-decadal scale variability in the eastern Baltic cod fishery 1550-1860: Evidence and causes. Fisheries Research, 87(2-3), 106-119. https://doi.org/10.1016/j.fishres.2007.07.003
MacKenzie, Brian R. ; Bager, Maibritt ; Ojaveer, Henn ; Awebro, Kenneth ; Heino, Ulla ; Holm, Poul ; Must, Aadu. / Multi-decadal scale variability in the eastern Baltic cod fishery 1550-1860 : Evidence and causes. In: Fisheries Research. 2007 ; Vol. 87, No. 2-3. pp. 106-119.
@article{640cb1208a3711dcb2bd000ea68e967b,
title = "Multi-decadal scale variability in the eastern Baltic cod fishery 1550-1860: Evidence and causes",
abstract = "Identification of periods of high and low cod production, and the reasons for these periods, can increase understanding of variability in populations and ecosystems. In this study we investigate the multi-decadal and multi-century scale variations in the cod population in the eastern Baltic Sea (ICES Subdivisions 25-32). Analytically derived estimates of biomass are available since 1966. These estimates show that biomass increased in the late 1970s-early 1980s, but decreased nearly 10-fold until the early 1990s and is still well below the long-term average. Prior to 1966 the biomass of cod is unknown, as is the relative role of fishing, climate variability/regimes, eutrophication and reduction of marine mammal predator populations. We have begun to investigate whether historical fisheries information (landings, effort, distribution) from before the 1880s is available in Baltic archives and museums, and to what extent this information can be used to interpret variations in this population. We have located fisheries data for different parts of the Baltic for different time periods since the 1550s and have interpreted the findings using current process knowledge of oceanographic mechanisms affecting cod reproduction and ecology in the Baltic Sea. The recovered data show that the Baltic ecosystem was able to support modest-large cod populations even though it was oligotrophic and contained large populations of cod predators (e.g., marine mammals). Current ecosystem management policy in the Baltic as developed and implemented by organisations such as the International Council for the Exploration of the Sea (ICES), the Baltic Marine Environment Protection Commission (HELCOM), the nine coastal countries and the European Union includes recovery of the cod population, a reduction in nutrient loading and measures to promote recovery of seal and harbour porpoise populations. If these policies are successful, the role of predatory fish in the future Baltic could again be substantial and comparable to that which we show existed 450 years ago. However, such a scenario will also require a major reduction in cod fishing mortality and suitable hydrographic conditions which promote successful cod reproduction. Historical ecology investigations in the Baltic can contribute to scientifically based fishery and ecosystem management and recovery plans. {\circledC} 2007 Elsevier B.V. All rights reserved",
keywords = "Baltic Sea, Cod, Historical ecology, Fisheries, Ecosystem, Management",
author = "MacKenzie, {Brian R.} and Maibritt Bager and Henn Ojaveer and Kenneth Awebro and Ulla Heino and Poul Holm and Aadu Must",
year = "2007",
doi = "10.1016/j.fishres.2007.07.003",
language = "English",
volume = "87",
pages = "106--119",
journal = "Fisheries Research",
issn = "0165-7836",
publisher = "Elsevier BV",
number = "2-3",

}

MacKenzie, BR, Bager, M, Ojaveer, H, Awebro, K, Heino, U, Holm, P & Must, A 2007, 'Multi-decadal scale variability in the eastern Baltic cod fishery 1550-1860: Evidence and causes', Fisheries Research, vol. 87, no. 2-3, pp. 106-119. https://doi.org/10.1016/j.fishres.2007.07.003

Multi-decadal scale variability in the eastern Baltic cod fishery 1550-1860 : Evidence and causes. / MacKenzie, Brian R.; Bager, Maibritt; Ojaveer, Henn; Awebro, Kenneth; Heino, Ulla; Holm, Poul; Must, Aadu.

In: Fisheries Research, Vol. 87, No. 2-3, 2007, p. 106-119.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Multi-decadal scale variability in the eastern Baltic cod fishery 1550-1860

T2 - Evidence and causes

AU - MacKenzie, Brian R.

AU - Bager, Maibritt

AU - Ojaveer, Henn

AU - Awebro, Kenneth

AU - Heino, Ulla

AU - Holm, Poul

AU - Must, Aadu

PY - 2007

Y1 - 2007

N2 - Identification of periods of high and low cod production, and the reasons for these periods, can increase understanding of variability in populations and ecosystems. In this study we investigate the multi-decadal and multi-century scale variations in the cod population in the eastern Baltic Sea (ICES Subdivisions 25-32). Analytically derived estimates of biomass are available since 1966. These estimates show that biomass increased in the late 1970s-early 1980s, but decreased nearly 10-fold until the early 1990s and is still well below the long-term average. Prior to 1966 the biomass of cod is unknown, as is the relative role of fishing, climate variability/regimes, eutrophication and reduction of marine mammal predator populations. We have begun to investigate whether historical fisheries information (landings, effort, distribution) from before the 1880s is available in Baltic archives and museums, and to what extent this information can be used to interpret variations in this population. We have located fisheries data for different parts of the Baltic for different time periods since the 1550s and have interpreted the findings using current process knowledge of oceanographic mechanisms affecting cod reproduction and ecology in the Baltic Sea. The recovered data show that the Baltic ecosystem was able to support modest-large cod populations even though it was oligotrophic and contained large populations of cod predators (e.g., marine mammals). Current ecosystem management policy in the Baltic as developed and implemented by organisations such as the International Council for the Exploration of the Sea (ICES), the Baltic Marine Environment Protection Commission (HELCOM), the nine coastal countries and the European Union includes recovery of the cod population, a reduction in nutrient loading and measures to promote recovery of seal and harbour porpoise populations. If these policies are successful, the role of predatory fish in the future Baltic could again be substantial and comparable to that which we show existed 450 years ago. However, such a scenario will also require a major reduction in cod fishing mortality and suitable hydrographic conditions which promote successful cod reproduction. Historical ecology investigations in the Baltic can contribute to scientifically based fishery and ecosystem management and recovery plans. © 2007 Elsevier B.V. All rights reserved

AB - Identification of periods of high and low cod production, and the reasons for these periods, can increase understanding of variability in populations and ecosystems. In this study we investigate the multi-decadal and multi-century scale variations in the cod population in the eastern Baltic Sea (ICES Subdivisions 25-32). Analytically derived estimates of biomass are available since 1966. These estimates show that biomass increased in the late 1970s-early 1980s, but decreased nearly 10-fold until the early 1990s and is still well below the long-term average. Prior to 1966 the biomass of cod is unknown, as is the relative role of fishing, climate variability/regimes, eutrophication and reduction of marine mammal predator populations. We have begun to investigate whether historical fisheries information (landings, effort, distribution) from before the 1880s is available in Baltic archives and museums, and to what extent this information can be used to interpret variations in this population. We have located fisheries data for different parts of the Baltic for different time periods since the 1550s and have interpreted the findings using current process knowledge of oceanographic mechanisms affecting cod reproduction and ecology in the Baltic Sea. The recovered data show that the Baltic ecosystem was able to support modest-large cod populations even though it was oligotrophic and contained large populations of cod predators (e.g., marine mammals). Current ecosystem management policy in the Baltic as developed and implemented by organisations such as the International Council for the Exploration of the Sea (ICES), the Baltic Marine Environment Protection Commission (HELCOM), the nine coastal countries and the European Union includes recovery of the cod population, a reduction in nutrient loading and measures to promote recovery of seal and harbour porpoise populations. If these policies are successful, the role of predatory fish in the future Baltic could again be substantial and comparable to that which we show existed 450 years ago. However, such a scenario will also require a major reduction in cod fishing mortality and suitable hydrographic conditions which promote successful cod reproduction. Historical ecology investigations in the Baltic can contribute to scientifically based fishery and ecosystem management and recovery plans. © 2007 Elsevier B.V. All rights reserved

KW - Baltic Sea

KW - Cod

KW - Historical ecology

KW - Fisheries

KW - Ecosystem

KW - Management

U2 - 10.1016/j.fishres.2007.07.003

DO - 10.1016/j.fishres.2007.07.003

M3 - Journal article

VL - 87

SP - 106

EP - 119

JO - Fisheries Research

JF - Fisheries Research

SN - 0165-7836

IS - 2-3

ER -