Transient dynamics of an altered large marine ecosystem

  title={Transient dynamics of an altered large marine ecosystem},
  author={Kenneth T. Frank and Brian Petrie and Jonathan A. D. Fisher and William C. Leggett},
Overfishing of large-bodied benthic fishes and their subsequent population collapses on the Scotian Shelf of Canada’s east coast and elsewhere resulted in restructuring of entire food webs now dominated by planktivorous, forage fish species and macroinvertebrates. Despite the imposition of strict management measures in force since the early 1990s, the Scotian Shelf ecosystem has not reverted back to its former structure. Here we provide evidence of the transient nature of this ecosystem and its… 

Irruptive prey dynamics following the groundfish collapse in the Northwest Atlantic: an illusion?

The results of the re-analysis of the population dynamics and behaviour of herring on the eastern Scotian Shelf, lead to the conclusion that the SHO hypothesis, at least as it relates to the post-cod collapse dynamics of the affected Northwest Atlantic ecosystems, is not supported.

Towards a more balanced view of marine ecosystems

Frank et al. (Nature, 477, 2011, 86) hypothesize that the slow recovery of the Scotian Shelf ecosystem to its structure prior to the early 1990s is a result of the oscillatory, runaway consumption

Signatures of the collapse and incipient recovery of an overexploited marine ecosystem

Evidence is found that community-level signals of the collapse and recovery of the cod are apparent in the spatial and temporal dynamics of the broader groundfish community and should be useful for designing more effective management strategies to ensure the persistence of exploited marine ecosystems.

Trophic interactions between key predatory fishes and crustaceans: comparison of two Northwest Atlantic systems during a period of ecosystem change

The NL and nGSL ecosystems are similar in form and function, differ- ing from Canadian Atlantic ecosystems further south, but the implications of a change inpredation species from capelin to shrimp in these systems are unknown.

The rise of a marine generalist predator and the fall of beta diversity

Spatial β diversity of fish assemblages in the Barents Sea decreased with increasing cod abundance, while decadal scale changes in temperature did not play a significant role, indicating a reversibility of the Fish assemblage structure in response to changing levels of an apex predator.

The role of a dominant predator in shaping biodiversity over space and time in a marine ecosystem.

It is found that alpha and beta diversity increased with decreases in cod occurrence; fish communities were less homogeneous and more variable in systems where cod no longer dominated, and these effects were most pronounced in the colder north-eastern parts of the Scotian Shelf.

Overfishing and the Replacement of Demersal Finfish by Shellfish: An Example from the English Channel

It is argued that a network of fisheries closures would help rebalance the trophic status of the Channel and allow regeneration of marine ecosystems.

The rise of the three-spined stickleback – eco-evolutionary consequences of a mesopredator release

The phenotype distribution suggest that a novel low-predation regime favours sticklebacks with less armour, and an interaction between evolutionary and ecological effects of the stickleback take-over has the potential to affect food web dynamics.

Interactions between small pelagic fish and young cod across the north Atlantic.

The findings suggest that the strength of predation or competition effects on young cod varies among small pelagic species but appears consistently for Atlantic herring; this effect may need to be considered in recovery trajectories for depleted cod populations.



Decline in top predator body size and changing climate alter trophic structure in an oceanic ecosystem

The increase in prey biomass was associated primarily with declines in predator body size and secondarily to an increase in stratification, which resulted in a weakening of top predation pressure.

Integrated assessment of a large marine ecosystem : A case study of the devolution of the eastern scotian shelf, Canada

This review examines a large marine continental shelf ecosystem that has undergone dramatic hysteresis-like changes in the recent past, using a pragmatic approach that combines empirical, reductionist and holistic methods based on the integrated analysis of 55 primary and secondary biotic, abiotic, and human variables over a 43-year period.

Extinction, survival or recovery of large predatory fishes

  • R. MyersB. Worm
  • Environmental Science, Biology
    Philosophical Transactions of the Royal Society B: Biological Sciences
  • 2005
It is concluded that management of multi–species fisheries needs to be tailored to the most sensitive, rather than the more robust species, to initiate recovery of severely depleted communities.

Multi-level trophic cascades in a heavily exploited open marine ecosystem

This work shows for the first time a four-level community-wide trophic cascade in the open Baltic Sea, and suggests that in order to dampen the occasionally harmful algal blooms of the Baltic, effort should be addressed not only to control anthropogenic nutrient inputs but also to preserve structure and functioning of higher Trophic levels.

Cascading Effects of the Loss of Apex Predatory Sharks from a Coastal Ocean

Impacts of chronic overfishing are evident in population depletions worldwide, yet indirect ecosystem effects induced by predator removal from oceanic food webs remain unpredictable. As abundances of

Historical Overfishing and the Recent Collapse of Coastal Ecosystems

Ecological extinction caused by overfishing precedes all other pervasive human disturbance to coastal ecosystems, including pollution, degradation of water quality, and anthropogenic climate change.

Fish production and the marine ecosystems of the Scotian Shelf, eastern Canada

Fishery production and food webs have been studied on the Scotian Shelf and upper continental slope and it is suggested that there are basic differences in food chains and efficiencies between the two ecosystems that account for their differences in production.

Marine fish diversity on the Scotian Shelf, Canada

1. Marine life in offshore regions has not been fully censused, yet related conservation policy relies on our ability to identify areas of high biodiversity. 2. We assessed the census of marine

Structure and stability in exploited marine fish communities: quantifying critical transitions

This index of trophic structure indicates that warmer, species-rich, southern fish populations resist transformation from positive to negative predator–prey correlations at exploitation rates that can be double those in the colder, relatively species-poor, northern areas.