Reconciling overfishing and climate change with stock dynamics of Atlantic cod (Gadus morhua) over 500 years

2004 ◽  
Vol 61 (9) ◽  
pp. 1553-1557 ◽  
Author(s):  
G A Rose
Keyword(s):  
Little Ice Age ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Ice Age ◽  
Production Model ◽  
Late 20Th Century ◽  
Climate Effects ◽  
Lower Productivity ◽  
History Of ◽  
The 1960S

To examine overfishing and climate effects on depleted cod (Gadus morhua) stocks, a surplus production model based on reconstructions of cod catch in Newfoundland was used to describe biomass dynamics from 1505 to 2004. Productivity parameters r (population growth rate) and K (carrying capacity) were assigned by fitting model to survey biomass. Assumptions of fishery-only influences inferring constant, random, or depensatory parameters fared poorly (did not mimic history), as did climate influences indexed by tree ring growth. However, a model using both climate and depensation fared well, mimicking much documented history of Newfoundland cod, including declines during the Little Ice Age (mid- to late 19th century) and the stock collapses of the late 20th century, with a good fit to recent scientific surveys (r2 = 0.80). This model suggests temporal differentiation between fishing and climate effects, including (i) declines during the Little Ice Age (1800–1880) caused by lower productivity, (ii) collapses in the 1960s caused by overfishing, (iii) collapses in the late 1980s caused by both, and (iv) rebuilding now hindered by depensatory effects of low numbers.

Mangrove dynamics in the southwestern Caribbean since the ‘Little Ice Age’: A history of human and natural disturbances

The Holocene ◽  
2010 ◽  
Vol 20 (6) ◽  
pp. 849-861 ◽  
Author(s):  
Catalina González ◽  
Ligia Estela Urrego ◽  
José Ignacio Martínez ◽  
Jaime Polanía ◽  
Yusuke Yokoyama
Keyword(s):  
Little Ice Age ◽  
Ice Age ◽  
Natural Disturbances ◽  
History Of ◽  
Mangrove Dynamics

scholarly journals Neoglacial history of Robson Glacier, British Columbia

2017 ◽  
Vol 54 (11) ◽  
pp. 1153-1164 ◽  
Author(s):  
B.H. Luckman ◽  
M.H. Masiokas ◽  
K. Nicolussi
Keyword(s):  
British Columbia ◽  
Little Ice Age ◽  
Ice Age ◽  
Tree Line ◽  
Canadian Rockies ◽  
The Holocene ◽  
Forest Sites ◽  
History Of ◽  
Subfossil Wood ◽  
Glacier Advance

As glaciers in the Canadian Rockies recede, glacier forefields continue to yield subfossil wood from sites overridden by these glaciers during the Holocene. Robson Glacier in British Columbia formerly extended below tree line, and recession over the last century has progressively revealed a number of buried forest sites that are providing one of the more complete records of glacier history in the Canadian Rockies during the latter half of the Holocene. The glacier was advancing ca. 5.5 km upvalley of the Little Ice Age terminus ca. 5.26 cal ka BP, at sites ca. 2 km upvalley ca. 4.02 cal ka BP and ca. 3.55 cal ka BP, and 0.5–1 km upvalley between 1140 and 1350 A.D. There is also limited evidence based on detrital wood of an additional period of glacier advance ca. 3.24 cal ka BP. This record is more similar to glacier histories further west in British Columbia than elsewhere in the Rockies and provides the first evidence for a post-Hypsithermal glacier advance at ca. 5.26 cal ka BP in the Rockies. The utilization of the wiggle-matching approach using multiple 14C dates from sample locations determined by dendrochronological analyses enabled the recognition of 14C outliers and an increase in the precision and accuracy of the dating of glacier advances.

scholarly journals Lichenometry and Schmidt hammer tests in the Kaunertal glacier foreland (Ötztal Alps) during the AMADEE-15 Mars Mission Simulation

2017 ◽  
Vol 21 (4) ◽  
pp. 190-196
Author(s):  
Jan Czempiński ◽  
Maciej Dąbski
Keyword(s):  
Little Ice Age ◽  
Ice Age ◽  
Schmidt Hammer ◽  
Mars Mission ◽  
Frontal Part ◽  
Glacier Foreland ◽  
Glacier Front ◽  
Relative Stabilization ◽  
History Of ◽  
Mission Simulation

AbstractThe aim of this article is to show the results of the lichenometrical and Schmidt hammer measurements performed in 2015 during the AMADEE-15 Mars Mission Simulation in the Ötztal Alps in order to test the capabilities of analogue astronauts and collect information on the geomorphic history of the study area since the Little Ice Age (LIA). The results obtained differ significantly from our expectations, which we attribute to differences in the field experience of participants and the astronauts’ technical limitations in terms of mobility. However, the experiments proved that these methods are within the range of the astronauts’ capabilities. Environmental factors, such as i) varied petrography, ii) varied number of thalli in test polygons, and iii) differences in topoclimatic conditions between the LIA moraine and the glacier front, further inhibited simple interpretation. The LIA maximum of the Kaunertal glacier occurred in AD 1850, and relative stabilization of the frontal part of the rock glacier occurred in AD 1711.

scholarly journals Regional changes in vertebra morphology during ontogeny reflect the life history of Atlantic cod (Gadus morhua L.)

2013 ◽  
Vol 222 (6) ◽  
pp. 615-624 ◽  
Author(s):  
Per G. Fjelldal ◽  
Geir K. Totland ◽  
Tom Hansen ◽  
Harald Kryvi ◽  
Xiyuan Wang ◽  
...  
Keyword(s):  
Life History ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
History Of

The 1970s

2020 ◽  
Author(s):  
L. Benjamin Rolsky
Keyword(s):  
Culture Wars ◽  
Transitional Period ◽  
American People ◽  
Late 20Th Century ◽  
The Sixties ◽  
History Of ◽  
Formative Experiences ◽  
The 1960S ◽  
Nervous Breakdown ◽  
Governing Institutions

Few decades in the history of America resonate more with the American people than the 1960s. Freedom, justice, and equality seemed to define the immediate futures of many of America’s historically most ostracized citizens. Despite the nostalgia that tends to characterize past and present analyses of the sixties, this imaginative work is important to consider when narrating the subsequent decade: the 1970s. Such nostalgia in considering the 1960s speaks to a sense of loss, or something worked at but not quite achieved in the eyes of the nation and its inhabitants. What happened to their aspirations? Where did they retreat to? And, perhaps more importantly, to what extent did “the spirit” of the 1960s catalyze its antithesis in the 1970s? In many ways the 1970s was a transitional period for the nation because these years were largely defined by various instances of cultural, or tribal, warfare. These events and their key actors are often under-represented in histories of late-20th-century America, yet they were formative experiences for the nation and their legacy endures in contemporary moments of polarization, division, and contestation. In this sense the 1970s were neither “liberal” nor “conservative,” but instead laid the groundwork for such terms to calcify into the non-negotiable discourse now known simply as the culture wars. The tone of the time was somber for many, and the period may be best understood as having occasioned a kind of “collective nervous breakdown.” For some, the erosion of trust in America’s governing institutions presented an unparalleled opportunity for political and electoral revolution. For others, it was the stuff of nightmares. America had fractured, and it was not clear how the pieces would be put back together.

scholarly journals Accelerating retreat and high-elevation thinning of glaciers in central Spitsbergen

2016 ◽  
Vol 10 (3) ◽  
pp. 1317-1329 ◽  
Author(s):  
Jakub Małecki
Keyword(s):  
Little Ice Age ◽  
High Elevation ◽  
Comprehensive Analysis ◽  
Ice Age ◽  
The Arctic ◽  
Digital Elevation ◽  
Glacier Changes ◽  
The Mean ◽  
Geodetic Mass Balance ◽  
The 1960S

Abstract. Svalbard is a heavily glacier-covered archipelago in the Arctic. Dickson Land (DL), in the central part of the largest island, Spitsbergen, is relatively arid and, as a result, glaciers there are relatively small and restricted mostly to valleys and cirques. This study presents a comprehensive analysis of glacier changes in DL based on inventories compiled from topographic maps and digital elevation models for the Little Ice Age (LIA) maximum, the 1960s, 1990, and 2009/2011. Total glacier area has decreased by  ∼ 38 % since the LIA maximum, and front retreat increased over the study period. Recently, most of the local glaciers have been consistently thinning in all elevation bands, in contrast to larger Svalbard ice masses which remain closer to balance. The mean 1990–2009/2011 geodetic mass balance of glaciers in DL is among the most negative from the Svalbard regional means known from the literature.

scholarly journals Simulated retreat of Jakobshavn Isbræ since the Little Ice Age controlled by geometry

2018 ◽  
Vol 12 (7) ◽  
pp. 2249-2266 ◽  
Author(s):  
Nadine Steiger ◽  
Kerim H. Nisancioglu ◽  
Henning Åkesson ◽  
Basile de Fleurian ◽  
Faezeh M. Nick
Keyword(s):  
Little Ice Age ◽  
Ice Age ◽  
Climate Forcing ◽  
Relative Role ◽  
Regional Warming ◽  
History Of ◽  
The Impact ◽  
Term Response

Abstract. Rapid retreat of Greenland's marine-terminating glaciers coincides with regional warming trends, which have broadly been used to explain these rapid changes. However, outlet glaciers within similar climate regimes experience widely contrasting retreat patterns, suggesting that the local fjord geometry could be an important additional factor. To assess the relative role of climate and fjord geometry, we use the retreat history of Jakobshavn Isbræ, West Greenland, since the Little Ice Age (LIA) maximum in 1850 as a baseline for the parameterization of a depth- and width-integrated ice flow model. The impact of fjord geometry is isolated by using a linearly increasing climate forcing since the LIA and testing a range of simplified geometries. We find that the total length of retreat is determined by external factors – such as hydrofracturing, submarine melt and buttressing by sea ice – whereas the retreat pattern is governed by the fjord geometry. Narrow and shallow areas provide pinning points and cause delayed but rapid retreat without additional climate warming, after decades of grounding line stability. We suggest that these geometric pinning points may be used to locate potential sites for moraine formation and to predict the long-term response of the glacier. As a consequence, to assess the impact of climate on the retreat history of a glacier, each system has to be analyzed with knowledge of its historic retreat and the local fjord geometry.

scholarly journals Mountain glaciers of southeast Siberia: current state and changes since the Little Ice Age

2014 ◽  
Vol 55 (66) ◽  
pp. 167-176 ◽  
Author(s):  
E.Yu. Osipov ◽  
O.P. Osipova
Keyword(s):  
Little Ice Age ◽  
Snow Accumulation ◽  
Ice Age ◽  
High Mountain ◽  
Late 20Th Century ◽  
Glacier Inventory ◽  
Mountain Glaciers ◽  
Current State ◽  
Field Investigations ◽  
Glacier Changes

AbstractContemporary glaciers of southeast Siberia are located on three high-mountain ridges (east Sayan, Baikalsky and Kodar). In this study, we present an updated glacier inventory based on high- to middle-resolution satellite imagery and field investigations. The inventory includes 51 glaciers with a total area of - 15 km2. Areas of individual glaciers vary from 0.06 to 1.33 km2, lengths from 130 to 2010 m and elevations from 1796 to 3490 m. The recent ice maximum extents (Little Ice Age) have been delineated from terminal moraines. On average, debris-free surface area shrunk by 59% between 1850 and 2006/11 (0.37% a–1), by 44% between 1850 and 2001/02 (0.29% a–1) and by 27% between 2001/02 and 2006/11 (3.39% a–1). The Kodar glaciers have experienced the largest area shrinkage, while the area loss on Baikalsky ridge was more moderate. Glacier changes are mainly related to regional summer temperature increase (by 1.7-2.6C from 1970 to 2010). There are some differences in glacier response due to different spatial patterns of snow accumulation, local topography (e.g. glacier elevation, slope) and geological activity. The studied glaciers (especially of Kodar ridge) are the most sensitive in Siberia to climate change since the late 20th century.

Sign in / Sign up

Export Citation Format

Share Document