Inefficient predators and prey injuries in a population of giant stickleback

1988 ◽  
Vol 66 (9) ◽  
pp. 2036-2044 ◽  
Author(s):  
T. E. Reimchen
Keyword(s):  
Structural Damage ◽  
Gasterosteus Aculeatus ◽  
Juvenile Fish ◽  
Large Body ◽  
Gavia Immer ◽  
Skin Damage ◽  
Size Dependent ◽  
Queen Charlotte Islands ◽  
Theoretical Predictions ◽  
Podiceps Grisegena

I describe predator-induced injuries in a lake population of large-bodied Gasterosteus aculeatus from the Queen Charlotte Islands, British Columbia. Injuries, which included structural damage (fractured dorsal and pelvic spines) and skin lacerations (scars, abrasions, and punctures), were observed on 13.4% of the population. Bill imprints ("aviscars") from avian piscivores, including Podiceps grisegena and Gavia immer, occurred on one-third of the injured fish. Mean aviscar width (4.2 mm) was low in winter and higher in midsummer correlating with seasonal differences in the presence of avian taxa. One-half of the injured fish had fractured spines without any associated skin damage; sources of these injuries could not be verified although they probably resulted from avian piscivores and resident salmonids. Rate of spine regeneration, determined on artifically marked fish, was 1.09 mm over 26 months. Age of injuries, assessed by condition and regrowth of spines, included recent attacks (ca. 1 month or less, 6.3%) and old attacks (1–3 years, 40%). Thirty percent of skin injuries are undetectable after 1 year. Injuries were absent on juvenile fish (< 50 mm) but were common on adults, reaching an incidence of 32% on sub-samples of the largest fish (> 82 mm). These data are consistent with theoretical predictions of increased manipulation inefficiencies among gape-limited predators and can account in part for the evolution of large body size in this population. Mark–recapture studies on 12 272 adult stickleback (> 70 mm) showed that the probability of incurring a predator injury as an adult fish (0.09/year) is largely a consequence of total length of time in the population; this finding amplifies size-dependent trends in injury frequencies.

Spine deficiency and polymorphism in a population of Gasterosteus aculeatus: an adaptation to predators?

1980 ◽  
Vol 58 (7) ◽  
pp. 1232-1244 ◽  
Author(s):  
T. E. Reimchen
Keyword(s):  
Littoral Zone ◽  
Gasterosteus Aculeatus ◽  
Frictional Contact ◽  
Selective Pressure ◽  
Juvenile Fish ◽  
Gavia Immer ◽  
Adult Males ◽  
Queen Charlotte Islands ◽  
Adult Females ◽  
Spine Number

A population of Gasterosteus aculeatus from a muskeg lake on the Queen Charlotte Islands shows a spine polymorphism, with 80% lacking the second dorsal spine and 68% lacking the pelvic spines. Females were more prevalent among phenotypes with greater spine number, and males were more common among those with fewer spines. Adult females, as well as juveniles of both sexes with pelvic spines, were more frequent in the limnetic habitat, whereas adult males and juveniles without pelvic spines were common in the littoral region.Five species of piscivorous birds, each in low numbers, foraged in the lake. Extensive predation in the limnetic region by Gavia immer and, secondarily, Podiceps spp. is implicated as a selective pressure favouring the greater spined phenotype.Odonate Nymphs (Aeshna spp.) consumed juvenile fish in predation experiments and in the lake proper. Nymphs were common in the littoral zone, where submerged debris provided substrate for foraging. It is proposed that spine loss in this population of G. aculeatus is an adaptation to the hunting technique of Aeshna, whereby reduced external structures such as spines minimize frictional contact for a grappling predator. Experimental data and other gasterosteid populations are discussed with reference to these proposals.

Loon abundance and behaviour over four decades at a remote ecological reserve on Haida Gwaii, British Columbia, Canada

2021 ◽  
Vol 135 (1) ◽  
pp. 28-38
Author(s):  
Thomas Reimchen ◽  
Sheila Douglas
Keyword(s):  
British Columbia ◽  
Gasterosteus Aculeatus ◽  
Evolutionary Ecology ◽  
Inverse Correlation ◽  
Gavia Immer ◽  
Haida Gwaii ◽  
Average Wind Speed ◽  
The North ◽  
Common Loons ◽  
Ecological Reserve

Early studies (1976–1982) of the Drizzle Lake Ecological Reserve on Haida Gwaii, British Columbia focussed on the endemic Giant Threespine Stickleback (Gasterosteus aculeatus) and their predators. These surveys showed daily visits to the small lake (110 ha) by up to 59 adult non-breeding Common Loon (Gavia immer), an important stickleback predator and up to 19 breeding and non-breeding adult Red-throated Loon (Gavia stellata), which leave daily to forage in nearby marine waters. We continued loon surveys for 17 additional years (1983–1989, 2011–2020) and found that aggregations of non-breeding Common Loons occurred annually on the lake during July with maximum daily numbers of 78–83 individuals in 1987, 2018, and 2020 and a large increase from 2011 to 2020. We did not detect any relationship of these differences with the Pacific Decadal Oscillation but a significant inverse correlation with average wind speed. Average yearly numbers of Red-throated Loons declined by 50% from 1976 to 1989 and have remained low, with lowest numbers (<2) occurring in 2017. Two Red-throated Loon nesting territories on the lake were occupied from 1976 to 1995, with chicks occurring in 24 of 36 nests, but no successful nesting was observed on the lake over the last decade. The relative decline of Red-throated Loon in this reserve is similar to that reported in Arctic and Subarctic surveys of the species in the north Pacific and northern Europe. We discuss the implications for the evolutionary ecology of the sticklebacks and the conservation of the ecological reserve.

Size-Structured Morality in a Treespine Stickleback (Gastrosteus aculeatus) – Cutthroat Trout (Oncorhynchus clarki) Community

1990 ◽  
Vol 47 (6) ◽  
pp. 1194-1205 ◽  
Author(s):  
T. E. Reimchen
Keyword(s):  
Gasterosteus Aculeatus ◽  
Size Structure ◽  
Adult Population ◽  
Total Mortality ◽  
Cutthroat Trout ◽  
Oncorhynchus Clarki ◽  
Small Fish ◽  
Frequency Distributions ◽  
Queen Charlotte Islands ◽  
Young Of The Year

In a 112-ha bog lake on the Queen Charlotte Islands, British Columbia, small fish comprised the major element in the diet of cutthroat trout (Oncorhynchus clarki). Despite the presence of juvenile salmon and char in the lake, threespine stickleback (Gasterosteus aculeatus) was the most common fish in the diet (99.5%). Foraging activity appeared to be more frequent in littoral than in limnetic regions. Mark–recapture methods indicate an average population of 220 trout and 75 000 adult stickleback. Trout consumed an estimated 308 770 stickleback yearly (145 kg) of which 65% were taken during summer. Seventy-three percent of all fish consumed were young of the year and 2% were adults, the latter representing 4% of the adult population in the lake. There was a 75% reduction in total mortality between successive year classes of stickleback (0,1,2,3 +). This consumption curve, which resembles a typical survivorship curve of fish, is a function of the size-structure of the populations and includes interactions between size availability of stickleback, prey-size preferences of the trout, and length frequency distributions of trout. Total weight of stickleback consumed by trout comprised about 40% of that previously calculated for 16 species of avian piscivores in the lake.

Size Dependent Bond Length of Metallic Clusters by Considering Bond Number

2016 ◽  
Vol 850 ◽  
pp. 314-318
Author(s):  
Hui Li ◽  
Hao Jie Xiao ◽  
Jiang Wang ◽  
Hai Xia Zhang ◽  
Hai Cheng Xuan ◽  
...  
Keyword(s):  
Bond Length ◽  
Bond Number ◽  
Single Bond ◽  
Metallic Clusters ◽  
Structure Relaxation ◽  
Atomic Structures ◽  
Size Dependent ◽  
Model Free ◽  
Theoretical Predictions ◽  
Ag Clusters

In this study, size-dependent bond length of metallic clusters is established by introducing bond number. This model, free of any adjustable parameters, can be utilized to predict the change rule of bond length with size. If the atomic structure of a cluster is known, the size and shape-dependent bond number are obtained. The cubooctahedral structure is taken for simplicity to describe the shape and geometric characteristics of metallic clusters. It is found that the bond length decreases with the decreased size of metallic clusters, which is due to the structure relaxation and enhanced single bond energy. The theoretical predictions are consistent with the evidences of the simulations for Au and Ag clusters. This confirms the validity of taking cubooctahedron structure, even if the simulated Au and Ag clusters are not cuboctahedron ones. This can be expected to other metallic clusters even with other atomic structures.

Diving depths and diet of Cassin's Auklet at Reef Island, British Columbia

1990 ◽  
Vol 68 (7) ◽  
pp. 1572-1577 ◽  
Author(s):  
Alan E. Burger ◽  
David W. Powell
Keyword(s):  
British Columbia ◽  
Juvenile Fish ◽  
Ammodytes Hexapterus ◽  
Queen Charlotte Islands ◽  
Cassin's Auklet ◽  
Ptychoramphus Aleuticus

Diving depths of Cassin's Auklets (Ptychoramphus aleuticus) breeding at Reef Island, Queen Charlotte Islands, British Columbia, were measured with miniature gauges attached to the birds. Maximum diving depths of 22 birds averaged 28 m, with a mode of 40 m. A time-at-depth recorder showed that one auklet dived to 29 m, but spent 80% of its time underwater at 3–13 m. Food delivered in gular pouches to chicks contained mainly euphausiids (predominantly Thysanoessa spinifera) and juvenile fish (Ammodytes hexapterus), with lesser amounts of copepods, amphipods, small pandalid shrimps, Brachyura larvae, and ctenophores. Euphausiid meals were most common during spring tides. Auklets that delivered significant amounts of euphausiids appeared to have dived deeper than those that delivered fish.

scholarly journals A Critical Review of Unmanned Aerial Vehicles (UAVs) Use in Architecture and Urbanism: Scientometric and Bibliometric Analysis

2021 ◽  
Vol 11 (21) ◽  
pp. 9966
Author(s):  
Marta Videras Rodríguez ◽  
Sergio Gómez Melgar ◽  
Antonio Sánchez Cordero ◽  
José Manuel Andújar Márquez
Keyword(s):  
Remote Sensing ◽  
Literature Review ◽  
Unmanned Aerial Vehicles ◽  
Bibliometric Analysis ◽  
Critical Review ◽  
Structural Damage ◽  
Road Traffic ◽  
Large Body ◽  
Relevant Information ◽  
Aerial Vehicles

In recent years the use of UAVs (Unmanned aerial vehicles) have proliferated in the civil sector for purposes such as search and rescue, remote sensing or real-time monitoring of road traffic, among others. In the architecture, engineering and construction fields (AEC) UAVs have demonstrated to be an ideal technology due to their optimal performance in terms of time, precision, safety and cost. Given the rapid growth of interest in this technology, this research presents a critical review of the literature on the use of UAVs in architecture and urbanism to define the most widely used techniques and delimit the fields of application based on the experimentation published by the scientific community. A scientific mapping was carried out in two stages using the VOSviewerTM software: a scientometric and a bibliometric analysis. This technique allowed us to analyse a large body of literature and bibliographic data to obtain trends, patterns and directions of this domain of knowledge. Then, a literature review was presented, highlighting the relevant information identified in the previous analysis. The fields of application of UAVs were delimited and the most commonly used payload types and the most appropriate post-processing techniques were specified, depending on the aerial mission objective. The fields of application identified included different techniques related to the generation of 3D models, land mapping, construction site monitoring, building surveying to detect structural damage and energy losses and urban remote sensing. The literature review showed that UAVs provide a useful multi-tasking tool at any stage of an architectural project. These techniques can be applied to buildings or public spaces from the design and construction processes when the project is initiated to the later stages of maintenance and inspection of the building during its life cycle.

scholarly journals Simple determination of the axial stiffness for largediameter independent wire rope core or fibre core wire ropes

2003 ◽  
Vol 38 (6) ◽  
pp. 577-586 ◽  
Author(s):  
M Raoof ◽  
T. J Davies
Keyword(s):  
Large Diameter ◽  
Large Body ◽  
Theoretical Models ◽  
Wire Rope ◽  
Axial Stiffness ◽  
Practical Applications ◽  
Wire Ropes ◽  
Theoretical Predictions ◽  
Computer Based ◽  
Iterative Procedures

Raoof and Kraincanic recently developed two somewhat different theoretical models for analysing large-diameter wire ropes with either an independent wire rope core (IWRC) or a fibre core. Most importantly, unlike all of the previously available theories (with their often very lengthy mathematical formulations), very encouraging correlations have been found between Raoof and Kraincanic's theoretical predictions of wire rope axial stiffnesses and a fairly large body of experimental data from other sources, hence providing ample support for the reliability of both theoretical models. Raoof and Kraincanic's original models were, however, computer based and involved certain iterative procedures. This potential drawback for practical applications (in an area where, by tradition, the rule of thumb reigns supreme) is overcome in the present paper, which reports details of some simplified (but still accurate) procedures for predicting the no-slip and/or full-slip axial stiffnesses of wire ropes with either an independent wire rope core or a fibre core, with the proposed formulations being amenable to simple hand calculations using a pocket calculator, which is of value to busy practising engineers.

Mitochondrial DNA patterns among endemic stickleback from the Queen Charlotte Islands: a preliminary survey

1989 ◽  
Vol 67 (5) ◽  
pp. 1324-1328 ◽  
Author(s):  
M. H. Gach ◽  
T. E. Reimchen
Keyword(s):  
Mitochondrial Dna ◽  
Gasterosteus Aculeatus ◽  
Size Variation ◽  
Sequence Divergence ◽  
Isolated Populations ◽  
Base Pairs ◽  
Queen Charlotte Islands ◽  
Freshwater Habitats ◽  
Unique Restriction ◽  
High Degree

Mitochondrial DNA (mtDNA) restriction fragments were analyzed in 30 individuals from four populations of Gasterosteus aculeatus from the Queen Charlotte Islands, British Columbia. Two morphologically divergent endemic freshwater populations (Boulton Lake, Drizzle Lake), a typical stream form, and a brackish form were sampled. mtDNA size variation of 70 to 180 base pairs was noted among individuals from all populations, and 1.1 and 5.0 kilobase duplications were observed in mtDNAs from two individuals. Analysis of 75 mtDNA fragments produced by five restriction endonucleases revealed seven clones differing by less than 1.0% sequence divergence. While the high degree of genetic similarity is consistent with a postglacial origin of these populations, the presence of a unique restriction site among geographically isolated populations suggests that these endemics may have had a common freshwater ancestor that inhabited periglacial freshwater habitats rather than being independently derived from marine forms.

Origins of endemic stickleback from the Queen Charlotte Islands: mitochondrial and morphological evidence

1996 ◽  
Vol 74 (6) ◽  
pp. 1045-1056 ◽  
Author(s):  
B. E. Deagle ◽  
T. E. Reimchen ◽  
D. B. Levin
Keyword(s):  
Gasterosteus Aculeatus ◽  
Glacial Refugium ◽  
Morphological Evidence ◽  
Western Canada ◽  
Mitochondrial Lineage ◽  
Queen Charlotte Islands ◽  
The Pacific ◽  
Mtdna Lineages ◽  
Enzyme Test ◽  
The Western Pacific

Recently, two divergent mitochondrial lineages were described in a survey of 12 scattered populations of the threespine stickleback (Gasterosteus aculeatus) on the Queen Charlotte Islands (QCI), western Canada, one of which, possibly a relict lineage, was subsequently shown to characterize stickleback from the western Pacific near Japan. In the present study, we assayed 985 fish from 85 QCI populations for mitochondrial lineage using a restriction enzyme test. Our data indicate that the relict lineage was largely limited (18 of 20 populations) to adjacent watersheds in the northeast corner of the QCI close to a suspected glacial refugium, but we also found the lineage in two remote lakes on the west coast of the QCI, distant from any known refugia. We obtained a sample of 33 stickleback from the mid-Pacific and found both mitochondrial DNA (mtDNA) lineages, strongly suggesting ongoing dispersal of these fish across the Pacific, and inconsistent with previous suggestions of relict status for one of the lineages. Morphologically derived traits, such as loss of armour and loss of spines, occurred in both lineages, but these were more prevalent in the Japanese lineage. Surprisingly, 19 localities had both lineages, and within each of these there were no significant univariate or multivariate associations between lineages and morphology, suggesting few if any reproductive barriers between the divergent mtDNA lineages.

Parasitism of asymmetrical pelvic phenotypes in stickleback

1997 ◽  
Vol 75 (12) ◽  
pp. 2084-2094 ◽  
Author(s):  
T. E. Reimchen
Keyword(s):  
Genetic Background ◽  
Gasterosteus Aculeatus ◽  
Parasite Species ◽  
Juvenile Fish ◽  
Bilateral Symmetry ◽  
Early Ontogeny ◽  
Directional Asymmetry ◽  
Lower Infection ◽  
Resistance To Infection ◽  
Multiple Species

Subtle departures from bilateral symmetry in morphological traits result from environmental and genetic stresses and may signal an inferior genetic background. Because one correlate of an inferior genome is reduced resistance to infection, such asymmetry may provide a phenotypic signal of susceptibility to parasitism. I tested this hypothesis in a population of threespine stickleback (Gasterosteus aculeatus) with cestode and nematode infections and bilateral asymmetry of the pelvis. Seventeen percent of the fish had an asymmetrical pelvis and, of these, 78% had greater expression on the left side; this directionality suggests a genetic influence. Females had consistently greater left-side asymmetry than did males. The incidence of total infection (all parasite species) in the largest adult fish (> 60 mm body length) was greater in asymmetrical phenotypes, and this occurred in both sexes and for each parasite species (Schistocephalus solidus, Cyathocephalus truncatus, Eustrongylides spp.), even when multiple-species infections were excluded. Contrary to prediction, however, in juvenile fish (< 20 mm) and yearlings (20–40 mm) but not subadults and adults (40–60 mm), asymmetrical phenotypes had significantly lower infection rates than symmetrical fish. This pattern occurred in both sexes, but the extent of the association varied over the 14 years of sampling. Consequently, if the directional asymmetry of the pelvis is under genetic control, asymmetry would be favoured during early ontogeny but selected against during the adult stages. The data support the hypothesis that asymmetry is a phenotypic signal of parasitism, but the unexpected bidirectionality of the association within a single population suggests increased complexity of the processes coupling asymmetry and genetic background.

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