Correlates of recovery for Canadian Atlantic cod (Gadus morhua)1This review is part of the virtual symposium “Flagship Species – Flagship Problems” that deals with ecology, biodiversity and management issues, and climate impacts on species at risk and of Canadian importance, including the polar bear (Ursus maritimus), Atlantic cod (Gadus morhua), Piping Plover (Charadrius melodus), and caribou (Rangifer tarandus).

2011 ◽  
Vol 89 (5) ◽  
pp. 386-400 ◽  
Author(s):  
Jeffrey A. Hutchings ◽  
Robert W. Rangeley
Keyword(s):  
Financial Incentives ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Size Structure ◽  
Interspecific Interactions ◽  
Economic Benefits ◽  
Climate Impacts ◽  
Reference Points ◽  
Charadrius Melodus

The collapse of Atlantic cod ( Gadus morhua L., 1758) in the early 1990s, perhaps the greatest numerical loss of a Canadian vertebrate (1.5–2.5 billion reproductive individuals), is one from which the species has yet to recover. Populations, or stocks, are at or well below their conservation reference points. The lack of recovery has been linked to ongoing fishing mortality (targeted, bycatch), changes to life history (reductions in age and size at maturity, truncations in age and size structure), and increased natural mortality. Emergent and demographic Allee effects, coupled with altered interspecific interactions, render questionable the presumption that the recovery of heavily depleted populations can be reliably forecasted by population dynamical behaviour during decline. Contrary to international commitments and inconsistent with fishery rebuilding plans elsewhere, cod recovery plans exclude target and limit reference points, recovery timelines, and harvest control rules. We suggest that the long-term biodiversity, social, and economic benefits associated with cod recovery can be realised by novel changes, including quantitatively responsible recovery plans based on science-determined reference points, new or revised legislation, integrated management strategies, strengthened sustainable seafood certification practices, expansion of marine spatial planning and protected areas, and novel financial incentives for investment in long-term, sustainable fisheries.

Conservation of caribou (Rangifer tarandus) in Canada: an uncertain future1This review is part of the virtual symposium “Flagship Species – Flagship Problems” that deals with ecology, biodiversity and management issues, and climate impacts on species at risk and of Canadian importance, including the polar bear (Ursus maritimus), Atlantic cod (Gadus morhua), Piping Plover (Charadrius melodus), and caribou (Rangifer tarandus).

2011 ◽  
Vol 89 (5) ◽  
pp. 419-434 ◽  
Author(s):  
M. Festa-Bianchet ◽  
J.C. Ray ◽  
S. Boutin ◽  
S.D. Côté ◽  
A. Gunn
Keyword(s):  
Climate Change ◽  
Industrial Development ◽  
Gadus Morhua ◽  
Rangifer Tarandus ◽  
Atlantic Cod ◽  
High Arctic ◽  
Climate Impacts ◽  
Past Century ◽  
Charadrius Melodus ◽  
Industrial Activities

Caribou ( Rangifer tarandus (L., 1758)) play a central role in the ecology and culture of much of Canada, where they were once the most abundant cervid. Most populations are currently declining, and some face extirpation. In southern Canada, caribou range has retreated considerably over the past century. The ultimate reason for their decline is habitat alterations by industrial activities. The proximate causes are predation and, to a lesser extent, overharvest. The most southerly populations of “Mountain” caribou are at imminent risk of extirpation. Mountain caribou are threatened by similar industrial activities as Boreal caribou, and face increasing harassment from motorized winter recreational activities. Most populations of “Migratory Tundra” caribou are currently declining. Although these caribou fluctuate in abundance over decades, changing harvest technologies, climate change, increasing industrial development and human presence in the North raise doubts over whether recent declines will be followed by recoveries. The Peary caribou ( Rangifer tarandus pearyi J.A. Allen, 1902), a distinct subspecies endemic to Canada’s High Arctic, has suffered drastic declines caused by severe weather, hunting and predation. It faces an increasing threat from climate change. While some questions remain about the reasons for the decline of Migratory Tundra caribou, research has clearly identified several threats to the persistence of “Boreal”, Mountain, and Peary caribou. Scientific knowledge, however, has neither effectively influenced policies nor galvanized public opinion sufficiently to push governments into effective actions. The persistence of many caribou populations appears incompatible with the ongoing pace of industrial development.

Habitat loss, climate change, and emerging conservation challenges in Canada1This review is part of the virtual symposium “Flagship Species – Flagship Problems” that deals with ecology, biodiversity and management issues, and climate impacts on species at risk and of Canadian importance, including the polar bear (Ursus maritimus), Atlantic cod (Gadus morhua), Piping Plover (Charadrius melodus), and caribou (Rangifer tarandus).

2011 ◽  
Vol 89 (5) ◽  
pp. 435-451 ◽  
Author(s):  
Laura E. Coristine ◽  
Jeremy T. Kerr
Keyword(s):  
Climate Change ◽  
Habitat Loss ◽  
Gadus Morhua ◽  
Rangifer Tarandus ◽  
Atlantic Cod ◽  
Climate Impacts ◽  
Charadrius Melodus ◽  
Species Dispersal ◽  
Mean Values ◽  
Pests And Diseases

In Canada, habitat loss has pushed many more species to the brink of extinction than expected in a region with extensive wilderness. However, species richness gradients depend strongly on climate, so species are concentrated in southern regions, where agricultural and urban land uses are both intensive and extensive. Agricultural pesticide use is associated with increasing rates of species endangerment in the south, but long-range transport of persistent organic pollutants is an emerging issue in remote northern regions. Because their distributions reflect climate so strongly, climate change threatens species throughout Canada. Evidence indicates that species’ distributions, phenologies, and interactions with pests and diseases are changing more rapidly in response to climate change than global mean values. Nevertheless, climate change is expected to impose dispersal requirements that surpass species’ maximum rates. Habitat losses may interact with climate change to impair species’ dispersal still further, creating the potential for widespread disruption of biological systems in the most diverse areas of Canada. New research is urgently needed to address questions, and the ethics, around species translocation, ecosystem engineering to anticipate future environmental conditions, and strategies to facilitate the persistence of rare species in landscapes dominated by human activities.

Conservation of Piping Plover (Charadrius melodus) in North America: science, successes, and challenges1This review is part of the virtual symposium “Flagship Species – Flagship Problems” that deals with ecology, biodiversity and management issues, and climate impacts on species at risk and of Canadian importance, including the polar bear (Ursus maritimus), Atlantic cod (Gadus morhua), Piping Plover (Charadrius melodus), and caribou (Rangifer tarandus).

2011 ◽  
Vol 89 (5) ◽  
pp. 401-418 ◽  
Author(s):  
C.L. Gratto-Trevor ◽  
S. Abbott
Keyword(s):  
Gadus Morhua ◽  
Rangifer Tarandus ◽  
Atlantic Cod ◽  
Public Support ◽  
Climate Impacts ◽  
Piping Plover ◽  
Charadrius Melodus ◽  
Predator Management ◽  
Piping Plovers ◽  
The Cost

There are only about 8000 Piping Plovers ( Charadrius melodus Ord, 1834) in existence. Because they depend on environments that are under intense human pressures and controls in both their breeding and wintering grounds, these birds and their habitats are highly managed in many areas across their range. Efforts to recover this endangered and threatened species have engaged thousands of people from Newfoundland to the Caribbean, and have provoked a ground-swell of public support and, at times, fury, as well as a considerable body of research. Although populations have increased substantially in the U.S. Atlantic and U.S. Great Lakes, this is not true of all regions. Significant issues still exist with respect to the efficacy of predator management; need for more accurate model input information; effects of climate, pollutants, and water management; habitat loss and degradation from recreation and development; and whether the cost and effort of management for this species can be maintained or increased where needed.

The influence of maternal effects in larval survival on fishery harvest reference points for two life-history patterns

2014 ◽  
Vol 71 (1) ◽  
pp. 151-161 ◽  
Author(s):  
Paul D. Spencer ◽  
Sarah B.M. Kraak ◽  
Edward A. Trippel
Keyword(s):  
Life History ◽  
Pacific Ocean ◽  
Maternal Effects ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Larval Survival ◽  
Reference Points ◽  
Life History Pattern ◽  
Gadus Macrocephalus ◽  
Potential Interactions

Increased larval viability with increased spawner age (i.e., maternal effects) have been observed in Atlantic cod (Gadus morhua) and Pacific rockfish (Sebastes spp.) stocks. Analytical results from a Beverton–Holt recruitment model indicate density-independent maternal effects affected the relative stock productivity and fishing rate reference points. We simulated populations based on Pacific cod (Gadus macrocephalus) and Pacific ocean perch (Sebastes alutus) to explore how estimates of reference points Fmsy and Fcrash are affected by maternal effects and potential interactions with life-history pattern, recruitment autocorrelation, and exploitation rate. Estimates of Fmsy and Fcrash were made from populations with maternal effects using either total larvae (proportional to eggs) or viable larvae (incorporating the maternal effect). Maternal effects have the largest impact upon estimated population productivity at high fishing rates. Estimates of Fmsy and Fcrash for cod were also affected by autocorrelated recruitment variability because of their reduced longevity compared with Pacific ocean perch. These results suggest the importance of evaluating the influence of maternal effects on estimated stock productivity on a case-by-case basis, particularly for depleted stocks composed of relatively young spawners.

Fish Catches and Long-Term Tidal Cycles in Northwest Atlantic Fisheries: A Nonlinear Regression Approach

1987 ◽  
Vol 44 (11) ◽  
pp. 1890-1897 ◽  
Author(s):  
Paul Cabilio ◽  
David L. DeWolfe ◽  
Graham R. Daborn
Keyword(s):  
New England ◽  
Nonlinear Regression ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Significant Negative Correlation ◽  
Clupea Harengus ◽  
Atlantic Menhaden ◽  
Melanogrammus Aeglefinus ◽  
Grand Banks

Selected long-term fisheries catch data from the New England – Fundy area and the Grand Banks were examined for concordance between changes in fish catches and the 18.6-yr nodal cycle of the tides using a nonlinear regression model. Significant positive correlations were found for Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus), alewife (Alosa pseudoharengus), Atlantic herring (Clupea harengus harengus), and scallop (Placopecten magellanicus), with lag times that are biologically appropriate for the time from hatching to recruitment into the fishery. A significant negative correlation with the nodal cycle was evident for Atlantic menhaden (Brevoortia tyrannus), for which this area constitutes the most northerly part of its range. Cod catches on the Grand Banks showed no correlation with the nodal cycle. It is suggested that the correlations between the nodal cycle and the changes in fish catches are caused by correlated changes either in sea surface temperature or in productivity resulting from changes in the degree of vertical mixing.

Flagship Species – Flagship Problems: recovery of species at risk and the conservation of biodiversity in Canada1This introduction is part of the virtual symposium “Flagship Species – Flagship Problems” that deals with ecology, biodiversity and management issues, and climate impacts on species at risk and of Canadian importance, including the polar bear (Ursus maritimus), Atlantic cod (Gadus morhua), Piping Plover (Charadrius melodus), and caribou (Rangifer tarandus).

2011 ◽  
Vol 89 (5) ◽  
pp. 369-370 ◽  
Author(s):  
J. Sherman Boates ◽  
M. Brock Fenton
Keyword(s):  
At Risk ◽  
Polar Bear ◽  
Gadus Morhua ◽  
Rangifer Tarandus ◽  
Atlantic Cod ◽  
Ursus Maritimus ◽  
Flagship Species ◽  
Piping Plover ◽  
Species At Risk ◽  
Charadrius Melodus

This is an Introduction to a series of review articles, entitled Flagship Species – Flagship Problems, that identify, review, and address key problems, solutions, and contradictions linked to conservation and recovery of four iconic species at risk in Canada (polar bear, Ursus maritimus Phipps, 1774; Atlantic cod, Gadus morhua L., 1758; Piping Plover. Charadrius melodus Ord, 1824; caribou, Rangifer tarandus (L., 1758)), as well as one review article dealing with the more systemic impacts of habitat loss and degradation. The reviews are cast in the context of the broader challenge of maintaining and restoring biodiversity.

scholarly journals Seasonal cycles in weight and condition in Atlantic cod (Gadus morhua L.) in relation to fisheries

2005 ◽  
Vol 62 (5) ◽  
pp. 1006-1015 ◽  
Author(s):  
L.G.S. Mello ◽  
G.A. Rose
Keyword(s):  
Gadus Morhua ◽  
Physiological Condition ◽  
Atlantic Cod ◽  
Management Strategies ◽  
Maximum Yield ◽  
Product Yield ◽  
Economic Benefits ◽  
Hepatosomatic Index ◽  
Economic Returns ◽  
Condition Indices

Abstract Seasonal cycle in weight and physiological condition of Atlantic cod (Gadus morhua) influenced productivity and economic impacts of the cod fishery in Placentia Bay, Newfoundland. Condition indices (Fulton's K condition factor and hepatosomatic index – HSI) were lowest during the spawning season (spring) and increased rapidly during the postspawning period, reaching maximum values by fall (K and HSI increased on average 24% and 82% between spring and fall, respectively). Somatic weight and condition indices varied seasonally. Condition indices were correlated with an industry index of product yield. Historically, cod fisheries have been prosecuted during all seasons, but simulations of 1997–1999 fisheries indicate that a fall fishery (period of peak physiological condition) resulted in a 8–17% decrease in the number of cod removed from the stock while maintaining the same weight-based quotas, and profiting from maximum yield and better product quality. Spring and summer fisheries resulted in lower yield (6%) and quality (5–26%) of fish products by weight. Seasonal biological cycles could be used as templates for management strategies that promote fisheries conservation and economic benefits by harvesting fish during periods when biological impacts are minimal and economic returns maximal.

Intergenerational valuation of fisheries resources can justify long-term conservation: a case study in Atlantic cod (Gadus morhua)

2005 ◽  
Vol 62 (5) ◽  
pp. 1104-1110 ◽  
Author(s):  
C H Ainsworth ◽  
U R Sumaila
Keyword(s):  
Discount Rate ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Ecosystem Model ◽  
Conventional Model ◽  
Fisheries Resources ◽  
Optimal Harvest ◽  
Harvest Policies

Where the conventional model of discounting advocates aggressive harvest policies, intergenerational discounting could have been used to render the historic gross overfishing of Atlantic cod (Gadus morhua) economically unappealing compared with a more conservative long-term strategy. Under these discounting approaches, we compare the historic harvest trend from 1985 (and projected postcollapse earnings) with theoretical optimal harvest profiles determined by an ecosystem model. The optimal scenarios generate less initial harvest than the historic profile but maintain the resource and provide greater yields over the long term. At a discount rate equal to market interest, we demonstrate that it was more economic under conventional valuation to harvest the cod stock to collapse than it would have been to sustain the population. However, under intergenerational valuation, the sustainable optimal scenarios outperform the actual harvest profile. Application of conventional discounting by fishing consortiums may be partly to blame for depletion, yet management fell short of even that ideal.

Short- and long-term effects of fish density and specific water flow on the welfare of Atlantic cod, Gadus morhua

Aquaculture ◽  
2011 ◽  
Vol 322-323 ◽  
pp. 184-190 ◽  
Author(s):  
Børge Damsgård ◽  
Frode Bjørklund ◽  
Helge K. Johnsen ◽  
Hilde Toften
Keyword(s):  
Water Flow ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Fish Density ◽  
Long Term Effects ◽  
Short And Long Term

Histopathological effects of crude oil on Atlantic cod following chronic exposure

1984 ◽  
Vol 62 (10) ◽  
pp. 2038-2043 ◽  
Author(s):  
R. A. Khan ◽  
J. Kiceniuk
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Giant Cells ◽  
Water Soluble ◽  
Similar Concentration ◽  
Long Term Effect ◽  
Flow Through ◽  
Kidney Lesions ◽  
Histopathological Effects

To assess the long-term effect on the tissues of marine fish, Atlantic cod, Gadus morhua L., were exposed to water-soluble fractions of Venezuelan and Hibernia crude oils at concentrations of 50–300 ppb for 12–13 weeks in a flow-through seawater system. Histopathological changes in oil-exposed fish included increased numbers of mucus-producing epithelial cells, capillary dilation, lamellar hyperplasia, and fusion of adjacent filaments in gills, microvesicular formation in hepatocytes, delayed spermatogenesis with intratubular multinucleated giant cells, and an increase of melanomacrophage centers in the spleen and kidney. Lesions were more prevalent and severe in fish exposed to Hibernia crude than to Venezuelan crude at a similar concentration.

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