scholarly journals Review of the ecosystem approach in Cumberland Sound, Nunavut, Canada

2021 ◽  
Author(s):  
Ross F. Tallman ◽  
Marianne Marcoux
Keyword(s):  
Life Histories ◽  
Arctic Charr ◽  
Ecosystem Approach ◽  
Mammal Species ◽  
Greenland Halibut ◽  
Ecosystem Effects ◽  
Species Dynamics ◽  
Cumberland Sound ◽  
By Catch ◽  
The Individual

Historically, fisheries have been monitored at the individual stock level, without consideration to connectivity to other species or activities in the ecosystem. The ecosystem approach requires that the stock and fishery be seen in the context of predators, competitors, prey, by-catch impacts, other fisheries and abiotic environmental variables so that management is holistic. In this review, we describe the components of the ecosystem approach applied in the scientific investigation of fisheries in Cumberland Sound, NU. Relative to other Canadian Arctic locales with commercial fisheries operations, the Cumberland Sound area has a greater biodiversity and abundance of fish and marine mammal species These components support active fisheries for Arctic Charr, Greenland Halibut, Beluga Whale as well as Ringed, Bearded and Harp Seal. The species and their fisheries are variable in character, their ecosystem effects and their response to the environment. We describe the species dynamics and their fisheries within an ecosystem context. We briefly note the challenges to developing an overarching model of the system such as the integration of the different life histories of the species, as well as the incorporation of future non-fisheries related disturbances.

Fish and invertebrate by-catch in the crab pot fishery in the Isle of Man, Irish Sea

2017 ◽  
Vol 98 (8) ◽  
pp. 2099-2111
Author(s):  
Fikret Öndes ◽  
Michel J. Kaiser ◽  
Lee G. Murray
Keyword(s):  
Irish Sea ◽  
Target Species ◽  
Catch Per Unit Effort ◽  
Isle Of Man ◽  
Ecosystem Effects ◽  
By Catch ◽  
Catch Rates ◽  
Taxonomic Groups ◽  
Catch Composition ◽  
Autumn And Winter

Baited trap or pot fisheries are considered to have relatively few wider ecosystem effects on the marine environment, particularly when compared with towed mobile fishing gear. However, this assumption is rarely tested in the field. This study aimed to determine the composition of non-target species that occur in crustacean pots and to assess spatial and temporal differences in catches in the waters around the Isle of Man, Irish Sea. The data were collected using fishery independent surveys and a questionnaire study. Based on fishery independent surveys, a total of five taxonomic groups and 43 species occurred as by-catch. The dominant by-catch species was velvet crab Necora puber. The by-catch per unit effort (BPUE) for all of the non-target species was low particularly in comparison to towed bottom gear fisheries around the Isle of Man. BPUE of species composition varied considerably between different locations around the Isle of Man. The results of both the fishery independent and questionnaire data suggested that the by-catch rates varied with season with peak BPUE occurring in spring which then declined into autumn and winter. By-catch composition did not decrease significantly with an increasing target species catch. Overall, by-catch was low relative to target species catch which may be partially attributable to the use of escape panels in pot fisheries in the Isle of Man.

Individual Growth and Reproduction

2019 ◽  
pp. 38-56
Author(s):  
Ken H. Andersen
Keyword(s):  
Life History ◽  
Growth Model ◽  
Life Histories ◽  
Maximum Size ◽  
Individual Growth ◽  
Energy Budgets ◽  
Asymptotic Size ◽  
The Individual ◽  
Growth And Reproduction

This chapter develops descriptions of how individuals grow and reproduce. More specifically, the chapter seeks to determine the growth and reproduction rates from the consumption rate, by developing an energy budget of the individual as a function of size. To that end, the chapter addresses the question of how an individual makes use of the energy acquired from consumption. It sets up the energy budgets of individuals by formulating the growth model using so-called life-history invariants, which are parameters that do not vary systematically between species. While the formulation of the growth model in terms of life-history invariants is largely successful, there is in particular one parameter that is not invariant between life histories: the asymptotic size (maximum size) of individuals in the population. This parameter plays the role of a master trait that characterizes most of the variation between life histories.

Challenges for Diadromous Fishes in a Dynamic Global Environment

2009 ◽  
Keyword(s):  
Life Cycle ◽  
Life Histories ◽  
Life Cycles ◽  
Partial Migration ◽  
Environmental Stochasticity ◽  
Species Dynamics ◽  
Life Cycle Pattern ◽  
Aquatic Sciences ◽  
Diversity Of Life

<em>Abstract</em>.-In the study of species life histories and the structure of diadromous populations, an emerging trend is the prevalence of life cycle diversity-that is, individuals within populations that do not conform to a single life cycle pattern. A rapid rise in publications documenting within-population variability in life cycles has resulted in the use of numerous terms and phrases. We argue that myriad terms specific to taxa, ecosystem types, and applications are in fact describing the same phenomenon-life cycle diversity. This phenomenon has been obscured by the use of multiple terms across applications, but also by the overuse of typologies (i.e., anadromy, catadromy) that fail to convey the extent of life cycle variations that underlay population, metapopulation, and species dynamics. To illustrate this, we review migration and habitat-use terms that have been used to describe life cycles and life cycle variation. Using a citation index (Cambridge Scientific Abstracts © Aquatic Sciences and Fisheries Abstracts), terms were tallied across taxonomic family, ecosystem, type of application, analytical approach, and country of study. Studies on life cycle diversity have increased threefold during the past 15 years, with a total of 336 papers identified in this review. Most of the 40 terms we identified described either sedentary or migratory lifetime behaviors. The sedentary-migratory dichotomy fits well with the phenomenon of partial migration, which has been commonly reported for birds and Salmonidae and is postulated to be the result of early life thresholds (switch-points). On the other hand, the lexicon supports alternate modes of migration, beyond the simple sedentary-migratory dichotomy. Here more elaborate causal mechanisms such as the entrainment hypothesis may have application. Diversity of life cycles in fish populations, whether due to partial migration, entrainment, or other mechanisms, is increasingly recognized as having the effect of offsetting environmental stochasticity and contributing to long-term persistence.

scholarly journals Comparative genetic structure reflects underlying life histories of three sympatric small mammal species in continuous forest of south-eastern Australia

Oikos ◽  
2007 ◽  
Vol 116 (11) ◽  
pp. 1819-1830 ◽  
Author(s):  
F. J. L. Kraaijeveld-Smit ◽  
D. B. Lindenmayer ◽  
A. C. Taylor ◽  
C. MacGregor ◽  
B. Wertheim
Keyword(s):  
Genetic Structure ◽  
Small Mammal ◽  
Life Histories ◽  
Mammal Species ◽  
South Eastern ◽  
Continuous Forest ◽  
Eastern Australia ◽  
Small Mammal Species ◽  
South Eastern Australia

scholarly journals First human-caused extinction of a cetacean species?

2007 ◽  
Vol 3 (5) ◽  
pp. 537-540 ◽  
Author(s):  
Samuel T Turvey ◽  
Robert L Pitman ◽  
Barbara L Taylor ◽  
Jay Barlow ◽  
Tomonari Akamatsu ◽  
...  
Keyword(s):  
Yangtze River ◽  
Eastern China ◽  
River System ◽  
Mammal Species ◽  
Cetacean Species ◽  
The Status ◽  
Global Extinction ◽  
By Catch ◽  
Neophocaena Phocaenoides Asiaeorientalis ◽  
Historical Range

The Yangtze River dolphin or baiji ( Lipotes vexillifer ), an obligate freshwater odontocete known only from the middle-lower Yangtze River system and neighbouring Qiantang River in eastern China, has long been recognized as one of the world's rarest and most threatened mammal species. The status of the baiji has not been investigated since the late 1990s, when the surviving population was estimated to be as low as 13 individuals. An intensive six-week multi-vessel visual and acoustic survey carried out in November–December 2006, covering the entire historical range of the baiji in the main Yangtze channel, failed to find any evidence that the species survives. We are forced to conclude that the baiji is now likely to be extinct, probably due to unsustainable by-catch in local fisheries. This represents the first global extinction of a large vertebrate for over 50 years, only the fourth disappearance of an entire mammal family since AD 1500, and the first cetacean species to be driven to extinction by human activity. Immediate and extreme measures may be necessary to prevent the extinction of other endangered cetaceans, including the sympatric Yangtze finless porpoise ( Neophocaena phocaenoides asiaeorientalis ).

Preliminary assessment of Greenland halibut diet in Cumberland Sound using stable isotopes

Polar Biology ◽  
2009 ◽  
Vol 32 (6) ◽  
pp. 941-945 ◽  
Author(s):  
Susan T. Dennard ◽  
Bailey C. McMeans ◽  
Aaron T. Fisk
Keyword(s):  
Stable Isotopes ◽  
Preliminary Assessment ◽  
Greenland Halibut ◽  
Cumberland Sound

scholarly journals Ecosystem effects of thermal manipulation of a whole lake, Lake Breisjøen, southern Norway (THERMOS project)

2007 ◽  
Vol 4 (5) ◽  
pp. 3357-3394 ◽  
Author(s):  
E. Lydersen ◽  
K. J. Aanes ◽  
S. Andersen ◽  
T. Andersen ◽  
P. Brettum ◽  
...  
Keyword(s):  
Heat Content ◽  
Thermocline Depth ◽  
Significant Shift ◽  
Particulate Carbon ◽  
Lake Chemistry ◽  
Ecosystem Effects ◽  
Macrophyte Community ◽  
Limiting Nutrient ◽  
Southern Norway ◽  
The Individual

Abstract. We conducted a 3-year artificial deepening of the thermocline in the dimictic Lake Breisjøen, southern Norway, by means of a large submerged propeller. An adjacent lake served as untreated reference. The manipulation increased thermocline depth from 6 to 20 m, caused a significant increase in the heat content, and delayed ice-on by about 20 days. There were only minor changes in water chemistry. Concentrations of sulphate declined, perhaps due to greater reduction of sulphate at the sediment-water interface. Concentrations of particulate carbon and nitrogen decreased, perhaps due to increased sedimantation velocity. Water transparency increased. There was no significant change in concentration of phosphorus, the growth-limiting nutrient. There were few significant changes in principal biological components. Phytoplankton biomass and productivity did not change, although the chlorophyll-a concentration showed a small decrease. Phytoplankton species richness increased, and the species composition shifted. Growth of periphyton increased. There was no change in the macrophyte community. The manipulation did not affect the zooplankton biodiversity, but caused a significant shift in the relative abundance (measured as biomass) in the two major copepod species. The manipulation did not affect the individual density, but appeared to have changed the vertical distribution of zoobenthos. Fish populations were not affected. The lake is oligotrophic and clearwater and the manipulation did not change the supply of phosphorus, and thus there were only minor changes in lake chemistry and biology. Effects might be larger in eutrophic and dystrophic lakes in which internal processes are stronger.

scholarly journals Beyond Perpetrators

2019 ◽  
pp. 153-172 ◽  
Author(s):  
Erin Jessee
Keyword(s):  
Transitional Justice ◽  
Life Histories ◽  
Rwandan Genocide ◽  
Political Actors ◽  
Official History ◽  
History Of ◽  
The Individual

This chapter considers the life histories of three convicted génocidaires—the term for those individuals who had some degree of criminal complicity in the 1994 Rwandan genocide. Since the genocide, the victorious Rwandan Patriotic Front (RPF) has, using a range of transitional justice mechanisms, disseminated an oversimplified official history of the genocide that divides the population into innocent Tutsi survivors or guilty Hutu perpetrators. However, convicted génocidaires’ actions surrounding the genocide were often more complex than the RPF’s official history acknowledges. For this reason, this chapter—building upon the work of Erica Bouris and Erin Baines—approaches génocidaires as ‘complex political actors.’ This framing allows for enhanced consideration of the individual circumstances that informed génocidaires’ actions. It similarly allows researchers to better comprehend génocidaires’ efforts to claim space as victims, bystanders, and survivors, for example, given the broader political, historical, and personal circumstances that informed their actions during the genocide.

scholarly journals Climbing behavior of Rhinella icterica (Spix, 1824) (Anura, Bufonidae): A typically terrestrial toad being scansorial

2020 ◽  
Vol 7 (16) ◽  
pp. 149-151
Author(s):  
Thiago Maia-Carneiro ◽  
Rodrigo Maia-Solidade
Keyword(s):  
Life Histories ◽  
Locomotor Behavior ◽  
Terrestrial Species ◽  
Climbing Behavior ◽  
The Family ◽  
The Individual ◽  
Spatial Resources

Toads of the Family Bufonidae do present diversified life histories, most of them are terrestrial, but there are aquatic and arboreal species. Rhinella icterica (Spix, 1824) (Anura, Bufonidae) is a ground dweller bufonid that use the habitat mainly horizontally. Here, we report the occurrence of climbing behavior in R. icterica, adding knowledge with respect to its types of locomotion. The individual was found on the ground and when perceived the presence of the observer it jumped to a wall, hit it, fell back to the ground, and then started to climb the wall. The toad climbed slowly, but apparently without difficulty, since it went up without slipping until the top of the ravine. Performing a given locomotor behavior even rarely confer additional ability to evade from threats and to access otherwise inaccessible food and spatial resources. Whether this behavior is common or rare in the genus is still obscure, nevertheless, at least some typically terrestrial species of Rhinella are capable of climbing and, as R. icterica, use the habitat vertically.

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