Extinction Risk and Overfishing: Reconciling Conservation and Fisheries Perspectives on the Status of Marine Fishes

Quantitative criteria used to assign species to categories of extinction risk may seriously overestimate these risks for marine fishes. Contemporary perception is that marine fishes may be less vulnerable to extinction than other taxa, because of great natural variability in abundance, high fecundity, rapid population growth, and an intrinsically high capability of recovering from low population size. Contrary to perception, however, there appears to be generally little theoretical or empirical support for the hypotheses that marine fish are more likely to experience large reductions in population size, to produce unusually high levels of recruitment, to have higher reproductive rates, or to recover more rapidly from prolonged population declines than nonmarine fishes. Although existing population-decline criteria may not accurately reflect probabilities of biological extinction, they do appear to reflect the converse-population recovery. Insufficient support for contemporary perceptions of their susceptibility to extinction, coupled with caveats associated with the assignment of extinction risk, suggest that significant increases in the population-decline thresholds used to assign marine fishes to at-risk categories would be inconsistent with a precautionary approach to fisheries management and the conservation of marine biodiversity.

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Using evidence of decline and extinction risk to identify priority regions, habitats and threats for plant conservation in Australia

Australian Journal of Botany ◽

10.1071/bt18056 ◽

2018 ◽

Vol 66 (7) ◽

pp. 541 ◽

Cited By ~ 2

Author(s):

J. L. Silcock ◽

R. J. Fensham

Keyword(s):

At Risk ◽

Threatened Species ◽

Extinction Risk ◽

Plant Conservation ◽

State Legislation ◽

Risk Of Extinction ◽

The Status ◽

Species Lists ◽

Key Issues ◽

Efficient Recovery

Threatened species lists are used at global, national and regional scales to identify species at risk of extinction. Many species are listed due to restricted population size or geographic distribution, and decline is often inferred rather than quantified. Vascular plants comprise over 70% of nationally listed threatened species, but there is an incomplete picture of which species are most at risk of extinction, where these occur and the factors behind their declines. We compiled published information and the best available field knowledge including 125 expert interviews to identify declining and at risk species. The candidate list comprised 1135 taxa, which were mostly listed as Critically Endangered or Endangered under Federal and/or State legislation, but included 80 that are currently unlisted but considered to be highly threatened. In total, 418 taxa were assessed as having a documented, suspected or projected continuing decline. These were ranked based on extinction risk and magnitude of continuing decline, which suggest that 296 are at risk of extinction under current management regimes, including 55 at high risk of extinction. Declining and imperilled taxa are concentrated in a relatively small number of regions and habitats, and six threatening processes are driving the majority of declines. Field surveys and robust, repeatable monitoring are required to better inform population trends and extinction risk, as well as inform the status of almost 200 taxa that are potentially imperilled but poorly known. Identification of declining taxa can identify key issues for flora conservation across a continent, and allow for targeted and efficient recovery efforts.

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The Ocean Pout, Zoarces americanus, and the Ocean Sunfish, Mola mola: Additions to the Marine Ichthyofauna of the Lower Saint John River System, New Brunswick, with a Summary of Marine Fish Reported from the Estuary

The Canadian Field-Naturalist ◽

10.22621/cfn.v127i1.1405 ◽

2013 ◽

Vol 127 (1) ◽

pp. 38 ◽

Cited By ~ 1

Author(s):

Donald F. McAlpine

Keyword(s):

New Brunswick ◽

River System ◽

Marine Species ◽

Sensu Stricto ◽

Marine Fishes ◽

Ocean Sunfish ◽

System A ◽

Mola Mola ◽

Saint John ◽

The Status

Recent records for the Ocean Pout, Zoarces americanus (collected 11 February 2011), and the Ocean Sunfish, Mola mola (photograph taken 24 June 2012), in the lower Saint John River system, New Brunswick, add to the list of marine fishes reported from this oceanographically unique estuary system. A total of 62 species of strictly freshwater, anadromous, catadromous, and marine fishes have now been recorded in the Saint John River system, with 49 of these in the Saint John River sensu stricto. The Acadian Redfish, Sebastes faciatus, a species assessed as threatened by the Committee on the Status of Endangered Wildlife in Canada, appears to be among these. While strictly marine fishes may contribute relatively little to the overall biomass of fishes in the Saint John River system, marine species account for 30.6% of the biodiversity of fishes in the river to date. This suggests that marine fishes may be a more significant component of the ichthyofauna of the lower Saint John River system than is generally recognized.

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Bomb radiocarbon dating of the endangered white abalone (Haliotis sorenseni): investigations of age, growth and lifespan

Marine and Freshwater Research ◽

10.1071/mf13007 ◽

2013 ◽

Vol 64 (11) ◽

pp. 1029 ◽

Cited By ~ 9

Author(s):

Allen H. Andrews ◽

Robert T. Leaf ◽

Laura Rogers-Bennett ◽

Melissa Neuman ◽

Heather Hawk ◽

...

Keyword(s):

Endangered Species ◽

Radiocarbon Dating ◽

Marine Invertebrate ◽

Extinction Risk ◽

Predictive Modelling ◽

Age And Growth ◽

Large White ◽

Adult Lifespan ◽

Bomb Radiocarbon ◽

The Status

Understanding basic life-history characteristics of white abalone (Haliotis sorenseni), such as estimated lifespan, is critical to making informed decisions regarding the recovery of this endangered species. All predictive modelling tools used to forecast the status and health of populations following restoration activities depend on a validated estimate of adult lifespan. Of the seven Haliotis species in California, white abalone is considered to have the highest extinction risk and was the first marine invertebrate listed as an endangered species under the Federal Endangered Species Act (ESA). Lifespan was previously estimated from observations of early growth; however, no study has generated ages for the largest white abalone. To address questions of age and growth, bomb radiocarbon (Δ14C) dating was used on shells from large white abalone. Measured bomb Δ14C levels were compared to regional Δ14C reference records to provide estimates of age, growth and lifespan. Bomb radiocarbon dating indicated that growth was variable among individuals, with a maximum estimated age of 27 years. The findings presented here provide support for previous age and growth estimates and an estimated lifespan near 30 years. These age data support the perception of a critical need for restoring the remnant aging and potentially senescent population.

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Extinction Risk in Endemic Marine Fishes

Conservation Biology ◽

10.1111/j.1523-1739.2011.01698.x ◽

2011 ◽

Vol 25 (5) ◽

pp. 1053-1055 ◽

Cited By ~ 22

Author(s):

J.-P. A. HOBBS ◽

G. P. JONES ◽

P. L. MUNDAY

Keyword(s):

Extinction Risk ◽

Marine Fishes

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The changing fates of the world's mammals

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2011.0116 ◽

2011 ◽

Vol 366 (1578) ◽

pp. 2598-2610 ◽

Cited By ~ 109

Author(s):

Michael Hoffmann ◽

Jerrold L. Belant ◽

Janice S. Chanson ◽

Neil A. Cox ◽

John Lamoreux ◽

...

Keyword(s):

Captive Breeding ◽

Extinction Risk ◽

Conservation Status ◽

Iucn Red List ◽

Red List ◽

Mammal Species ◽

International Union ◽

The Status ◽

Conservation Actions ◽

In The Wild

A recent complete assessment of the conservation status of 5487 mammal species demonstrated that at least one-fifth are at risk of extinction in the wild. We retrospectively identified genuine changes in extinction risk for mammals between 1996 and 2008 to calculate changes in the International Union for Conservation of Nature (IUCN) Red List Index (RLI). Species-level trends in the conservation status of mammalian diversity reveal that extinction risk in large-bodied species is increasing, and that the rate of deterioration has been most accelerated in the Indomalayan and Australasian realms. Expanding agriculture and hunting have been the main drivers of increased extinction risk in mammals. Site-based protection and management, legislation, and captive-breeding and reintroduction programmes have led to improvements in 24 species. We contextualize these changes, and explain why both deteriorations and improvements may be under-reported. Although this study highlights where conservation actions are leading to improvements, it fails to account for instances where conservation has prevented further deteriorations in the status of the world's mammals. The continued utility of the RLI is dependent on sustained investment to ensure repeated assessments of mammals over time and to facilitate future calculations of the RLI and measurement against global targets.

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Criteria to Define Extinction Risk in Marine Fishes: The American Fisheries Society Initiative

Fisheries ◽

10.1577/1548-8446(1999)024<0006:ctderi>2.0.co;2 ◽

1999 ◽

Vol 24 (12) ◽

pp. 6-14 ◽

Cited By ~ 155

Author(s):

J. A. Musick

Keyword(s):

Extinction Risk ◽

Marine Fishes

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Make the Adder Count: population trends from a citizen science survey of UK adders

Herpetological Journal ◽

10.33256/hj29.1.5770 ◽

2019 ◽

pp. 57-70 ◽

Cited By ~ 1

Author(s):

Emma Gardner

Keyword(s):

Habitat Management ◽

Extinction Risk ◽

Large Population ◽

Surveillance Programme ◽

Large Populations ◽

Management Plans ◽

The Status ◽

Priority Species ◽

Negative Impacts ◽

The Uk

Concern has been growing about the status of UK adder populations, with expert opinion reporting widespread declines. Assessing the true scale of these declines, however, has been hampered by a lack of quantitative data. Make the Adder Count began in 2005 as a national surveillance programme collecting standardised counts of adders lying-out after emerging from hibernation. 260 sites have contributed data, confirming a significant decline, on average, across sites with small populations, while the few with large populations (<10 % of sites) are weakly increasing. If these trends continue, within 15‒20 years, adders will be restricted to a few large population sites, significantly increasing the extinction risk for this priority species in the UK. Public pressure/disturbance was reported as the most frequent negative factor affecting sites, followed by habitat management and habitat fragmentation. Negative impacts from habitat management were reported almost as frequently as positive impacts, suggesting many management plans do not adequately consider the requirements of adders. The dataset also demonstrated earlier emergence among males, in warmer springs and at more northerly sites.

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Marine Fishes Expert Network: findings and recommendations from the Circumpolar Biodiversity Monitoring Program’s State of the Arctic Marine Biodiversity Report

10.7287/peerj.preprints.26780v1 ◽

2018 ◽

Author(s):

Kevin J Hedges ◽

Shannon MacPhee ◽

Hreiðar Þór Valtýsson ◽

Edda Johannesen ◽

Catherine W Mecklenburg

Keyword(s):

Marine Fish ◽

Marine Mammals ◽

Prey Availability ◽

Marine Fishes ◽

The Arctic ◽

Marine Biodiversity ◽

Transfer Energy ◽

Status And Trends ◽

The Status ◽

Expert Network

Pelagic and benthic fish species are important in Arctic marine ecosystems because they transfer energy to predators such as seabirds, marine mammals, as well as people. The CBMP Marine Fishes Expert Network aggregated and reviewed data on the population status and trends of three marine fish Focal Ecosystem Components (FECs) across eight Arctic Marine Areas. Fishes are affected by environmental conditions such as temperature, sea ice availability and salinity, and are constrained by prey availability and predator pressure, which can be influenced by climate change. The three marine fish FECs discussed here are indicative of different changes that are occurring in the Arctic and demonstrate the varied responses observed among species. The presentation will summarize current level of monitoring across the Arctic, the status and trends of FECs, drivers of observed trends, and knowledge and monitoring gaps.

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