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  • 1
    Electronic Resource
    Electronic Resource
    Ecological energetics of Nerita (Archaeogastropoda, Neritacea) populations on Barbados, West Indies (1971)
    Springer
    Marine biology 11 (1971), S. 12-22 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Population energy budgets estimated on the assumption of steady state conditions for Nerita tessellata Gmelin, N. versicolor Gmelin, and N. peloronta L. on Barbados, W. Indies, are presented. Large differences in population structure, and hence energetics, occurred at different localities along the beach. Relatively high proportions (81 to 88%) of the assimilated energy were lost via metabolism. Assimilation efficiencies ranged from 39 to 43%, net growth efficiencies from 5 to 13%, and ecological efficiencies from 3 to 7%. For each species, production (P), energy flow (A) and total energy consumption (C) were expressed as functions of animal size, in order to facilitate gross estimations of the energy components for other populations for which data on size-frequency and density are available. Respiration studies of all three species in the laboratory failed to detect differences between respiration rates in air or under seawater.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00348016
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Growth and reproductive rates of Littorina rudis from three contrasted shores in North Wales, UK (1980)
    Springer
    Marine biology 58 (1980), S. 47-54 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Data are presented on growth and reproductive rates of Littorina rudis Maton from 3 contrasted habitats: a sheltered saltmarsh, a moderately sheltered boulder shore and an exposed cliff face. Growth was fastest in L. rudis from the moderately sheltered boulder shore, followed closely by snails from the sheltered saltmarsh. Growth was much slower and the asymptotic size much less in L. rudis from the exposed cliff face, this being attributed to the reduced time available for foraging caused by longer and more erratic periods when the substratum dries out. Eggs extracted from the brood chambers of the saltmarsh L. rudis took about 72 d to hatch in the laboratory at 10°C. No seasonal trend was detected in the percentage of sexually mature snails, which fluctuated erratically round about 54 to 99% in each population. Similarly, the ratio of females: males fluctuated erratically about 1.0. The number of eggs and embryos held in the brood chamber peaked in May–June and birth rates (release of young from the brood chamber) peaked in July-August. Following a lull in August, the brood chamber contents were maintained at moderately high levels throughout the winter, whereas the birth rates declined to very low levels. These differences in the seasonal cycle of brood chamber contents and birth rates were probably caused by seasonal differences in embryological development rate and in the propensity of the young to leave the brood chamber. Fecundity increased with parental size and, because of this, the smaller, slower growing exposed-shore L. rudis had much lower potential fecundities than L. rudis from the other shores. However, the size-specific fecundity of the exposedshore L. rudis was about 1.7 times that of L. rudis on the more sheltered shores. This difference was apparently not attributable to smaller young or to a greater capacity of the brood chamber in the exposedshore L. rudis, and must therefore have been caused by higher rates of egg production. 18% of mature females from the boulder shore and 5% of those from the cliff face were oviparous, having a jelly gland in place of the brood chamber.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00386879
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  • 3
    Electronic Resource
    Electronic Resource
    Classification and ordination of benthic samples from Bedeque Bay, an estuary in Prince Edward Island, Canada (1971)
    Springer
    Marine biology 10 (1971), S. 227-235 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An attempt was made to identify the causes of the distribution of benthos within Bedeque Bay using multivariate techniques programmed for the computer. Both classification by a hierarchical cluster analysis, and ordination by principal components analysis suggested that a large proportion of the variance in the data was directly or indirectly correlated with a salinity gradient. Classification divided the species into two main groups, a in the upper half of the estuary where lower salinities and larger salinity fluctuations occurred, and group b in the lower half of the estuary with a more stable salinity regime. The group b species were further subdivided into those preferring soft mud and those preferring sandier sediments. The group a species were divided into a well-developed oyster association and various sub-groups less strongly associated with oysters. Five principal components were required to account for 50% of the variance in the data. The first axis accounted for 20% of the variance and was shown by a non-parametric test to be correlated with the salinity gradient. Axes II to V could not be interpreted, but possibly represented complex species interactions. By providing hard substrates and altering the natura of the sediment, oysters and mussels produced conditions suitable for many other species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00352811
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Self-fertilisation in Celleporella hyalina (1993)
    Springer
    Marine biology 115 (1993), S. 495-500 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Employing recently developed culture methods, 21 colonies of the hermaphroditic bryozoan Celleporella hyalina (L.) established as primary zooids, were grown in isolation for 70 or 79 d before being placed in a communal location, to investigate the possibility of autogamy. Colonies grew rapidly, with compact circular form and a low perimeter:area ratio. Autozooids and sexual zooids were produced as normal. Five colonies produced embryos after 5wk, and only two colonies remained barren for the duration of the isolation period. Placement in communal location was accompanied by substantially increased larval output. In control colonies where isolation was prolonged, brooding activity remained low. Abortion was frequent, and settlement of the few larvae produced in isolation was never observed. It was concluded that although self-fertilisation may be available as an “emergency option”, C. hyalina is routinely outcrossing in nature. The frequent abortion and apparent absence of settlement in autogamous offspring suggest that these offspring may be of reduced fitness.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349848
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  • 5
    Electronic Resource
    Electronic Resource
    Optimizing foraging behaviour through learning (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 41 (1992), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Manifestation of life-history strategy is through the allocation of resources acquired by foraging. Foraging efficiency can be improved by learning, as fishes adjust their behaviour to changing circumstances. We briefly review the influence of learning on the foraging behaviour of fishes and make recommendations for further research. We stress the importance of quantifying learning and memory in relation to ontogeny and life history.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1992.tb03870.x
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  • 6
    Electronic Resource
    Electronic Resource
    Hierarchical response to prey stimuli and associated effects of hunger and foraging experience in the fifteen-spined stickleback, Spinachia spinachia (L.) (1991)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 38 (1991), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Responsiveness of fifteen-spined sticklebacks, Spinachia spinachia (L.) to motility (rotating or still). size (larger or smaller), colour (red or green), shape (rectangular or tapered) and location (near bottom or surface of water) was investigated by presenting fish with binary choices of artificial prey, constructed from frozen mysids, trimmed, dyed and fixed to adjustable, motorized rods. Responsiveness was in the order movement 〉 size 〉 colour 〉 shape = location. In natural situations, movement may distinguish edible from inedible objects, while size indicates profitability and feasibility for attack. Colour, shape and location are more specific stimuli. Sticklebacks familiar with Artemia are more responsive to red coloration, tapered shape and pelagic location, as opposed to green, rectangular and benthic characterizing Gammarus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1991.tb03146.x
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  • 7
    Electronic Resource
    Electronic Resource
    The efficiency of adaptive search tactics for different prey distribution patterns: a simulation model based on the behaviour of juvenile plaice (2003)
    Oxford, UK; Malden, USA : Blackwell Science Ltd/Inc
    Journal of fish biology 63 (2003), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Juvenile plaice Pleuronectes platessa are particularly useful for studying forager search behaviour because their search paths are essentially two dimensional, and punctuated by natural stops. Their prey occur in a range of natural distributions from highly aggregated to over-dispersed. Juvenile plaice use area-restricted search near aggregated prey and extensive search, consisting of longer moves and fewer turns, between aggregations and when searching for dispersed prey. They search for less conspicuous prey items mainly in the pauses between movements. This saltatory search behaviour contrasts with the continuous search that is usually assumed in search models. A simulation model of saltatory search behaviour showed that a strategy combining extensive and intensive search allows the efficient exploitation of a range of natural prey distribution patterns, and that it is particularly effective when the search behaviour is controlled by perceived prey density. This allows the predator to respond to the localized aggregations which often occur in nature. The selective use of intensive search was more efficient than the continuous use of extensive search even in prey distribution patterns that were statistically over-dispersed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.2003.00212.x
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  • 8
    Electronic Resource
    Electronic Resource
    Adaptive search in juvenile plaice foraging for aggregated and dispersed prey (2002)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 61 (2002), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Juvenile plaice Pleuronectes platessa in a laboratory arena used intensive search behaviour, characterized by short movements and frequent turning, in the five movements before and after attacking a prey in an aggregated distribution. They used extensive search behaviour with, on average, longer movements and less turning at all other times. Intensive search was, apparently, triggered by a high local density of prey but not by isolated prey. This response to local prey density resulted in area-restricted search when prey were aggregated and win-shift behaviour when prey were dispersed. There was no evidence that the use of intensive search increased with experience of aggregated prey. It therefore appears that the fish were able to exploit encountered prey distribution patterns using their immediate perceptions rather than prior experience.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.2002.tb02469.x
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  • 9
    Electronic Resource
    Electronic Resource
    Artificial dietary regime may impair subsequent foraging behaviour of hatchery-reared turbot released into the natural environment (2002)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 61 (2002), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: When offered a size range of shrimp Crangon crangon, fewer naïve reared turbot Scophthalmus maximus fed than did wild fish, and those that fed took smaller prey. Analysis of feeding behaviour indicated differences between wild and naïve reared fish in the motivation to feed on novel prey and in prey recognition and capture efficiency. Feeding efficiency and motivation increased with experience and reared fish achieved the feeding rate of wild fish within the 9 days of the experiment. The ‘creep’ style of approach to shrimp was innate to naïve reared turbot. A comparative feeding experiment confirmed that experienced reared fish ate more prey than naïve reared fish. Naïve reared turbot selected pellets and attacked stones preferentially to shrimp, in contrast to wild and experienced reared fish, which selected shrimp. Stones were attacked due to the memory of pellet-like visual characteristics and this behaviour persisted in some reared fish for at least 6 weeks, illustrating a cost of memory in which changing environmental conditions cause previously learnt information to become misleading. The experimental data also demonstrated that differences may arise in the prey and feeding behaviour of wild and naïve reared fish, but that such differences diminish with experience.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.2002.tb01750.x
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  • 10
    Electronic Resource
    Electronic Resource
    Increased turning per unit distance as an area-restricted search mechanism in a pause-travel predator, juvenile plaice, foraging for buried bivalves (2000)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 56 (2000), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: During searching, discovery of a prey patch by juvenile plaice Pleuronectes platessa was associated with a change from extensive to intensive search behaviour several moves before an attack on a prey. Intensive search behaviour was characterized by reduced distance of moves, a greater rate of turning per unit distance and shorter pauses between moves. The increase in turn rate was associated with area-restricted seaching, while a decrease in distances moved suggests that plaice search more efficiently for prey when stationary than while moving. The klinokinetic mechanism that appears to regulate search behaviour in juvenile plaice should allow efficient exploitation of a range of prey distribution patterns based on localized cues alone. Such a mechanism is especially useful to a migratory predator, like plaice, whose foraging is subject to time constraints imposed by tidally available feeding areas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.2000.tb02160.x
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