Minimising waste through bioenergetically and behaviourally based feeding strategies

1995 ◽  
Vol 31 (10) ◽  
pp. 29-40 ◽  
Author(s):  
J. E. Thorpe ◽  
C. Young Cho
Keyword(s):  
Feeding Activity ◽  
Activity Patterns ◽  
Growth Efficiency ◽  
Wild Food ◽  
Feeding Strategies ◽  
Physico Chemical ◽  
Evolutionary Features ◽  
Feeding Regimes ◽  
In The Wild ◽  
Genetically Determined

Most species in aquaculture are new to cultivation and so behave like wild animals. They are products of evolution, with adaptations to specific habitat conditions. In the wild, food is not available uniformly throughout the day or the year, or in space, and rarely exceeds the fishes needs. Competition is energetically expensive, reducing growth efficiency. Consequently, feeding activity patterns have evolved, implying internal appetite rhythms, which optimise food intake under these various constraints. Salmonids can adapt quickly to short term variation in food availability, but show seasonal genetically determined anorexia. Rational feeding regimes in culture should take all such features into account. When appetite is high naturally, food should be presented so that it is economically indefensible - where every individual can eat, and where fighting does not pay. At periods of anorexia it will be prudent to offer no food. Manufacturers' feed tables are usually regimes devised to meet the bioenergetic needs of fishes, as they are understood in a physico-chemical sense. While useful first approximations, they do not take into account these evolutionary features of the fishes, and can lead to waste. Methods of presentation are described which allow the fish to determine when food shall be available, and in ways which, by diminishing the advantages of social dominance, ensure relatively even opportunities to feed for all individuals in the population. Allowing the fish to set the time-table reduces the likelihood of waste.

scholarly journals Occurrence of bottlenose dolphins (Tursiops truncatus) in the Río Negro Estuary, Argentina, and their mid-distance movements along the northeastern Patagonian coast

10.5597/00226 ◽  
2017 ◽  
Vol 11 (1-2) ◽  
pp. 170-177
Author(s):  
Mauricio Failla ◽  
Verónica A. Seijas ◽  
Els Vermeulen
Keyword(s):  
Tursiops Truncatus ◽  
Feeding Activity ◽  
Bottlenose Dolphins ◽  
Activity Patterns ◽  
Long Distance ◽  
Identification Rate ◽  
Photo Identification ◽  
Rio Negro ◽  
Patagonian Coast ◽  
Main Activity

A systematic study was carried out on bottlenose dolphins (Tursiops truncatus) in the Río Negro Estuary (RNE), Patagonia, Argentina, to analyze their occurrence and activity patterns in this region. The photo-identification data of this study was further compared to data from an adjacent region to gain information on the animals' movements along the northeastern Patagonian coast. Information was gathered through land-based observations between the months of March and July of 2008 up to 2011. Data on dolphin activity patterns were collected via an ad libitum focal-group sampling mode. At the same time, dorsal fin images were obtained from as many dolphins as possible for identification and subsequent re-identification of individuals. Total effort equaled 188h, resulting in 58h of observation of 124 dolphin groups [sightings per unit effort (SPUE) = 0.66 group/h]. Most of the groups observed contained between one and five individuals, and two main activity states could be determined, namely traveling (65%) and foraging (26%). The photo-identification effort, which started opportunistically in 2006, resulted in a catalogue of 17 individual dolphins, with a total mean re-identification rate of nine days (max. = 24 days). When comparing these pictures to the existing catalogue of Bahía San Antonio (BSA; approximately 200km west from the study area) dorsal fins of 15 individuals could be matched and most (n = 12) could be subsequently re-identified in both areas, indicating their long distance movements along the northeastern Patagonian coast during the austral autumn months. This season coincides with the lowest dolphin abundance and feeding activity in BSA. This study indicates that bottlenose dolphins enter the RNE to forage at least during autumn. It further suggests that the search for food resources is the main trigger for their movement patterns along the northeastern Patagonian coast during this season, at least for certain individuals. More research is needed to accurately confirm these hypotheses.

Observations on Activity Patterns, Population and Den Characteristics of The Water Rat Hydromys chrysogaster Along Badger Creek, Victoria.

1995 ◽  
Vol 18 (1) ◽  
pp. 71
Author(s):  
J.L. Gardner ◽  
M. Serena
Keyword(s):  
Population Density ◽  
Activity Patterns ◽  
Home Ranges ◽  
Adult Males ◽  
Fish Farms ◽  
Age Classes ◽  
Irrigation Channels ◽  
In Captivity ◽  
In The Wild ◽  
Hydromys Chrysogaster

The Water Rat Hydromys chrysogaster is Australia's largest amphibious rodent, occupying freshwater rivers, lakes, and coastal and estuarine habitats throughout the continent (Watts and Aslin 1981). Little is known of the species' social organisation or use of space in the wild although Harris (1978) suggested that adults might be intrasexually aggressive. The home ranges of all sex and age classes overlap to some extent but home ranges of adults of the same sex appear to overlap less (Harris 1978). Adult males occupy the largest home ranges which overlap those of one or more females. In captivity individuals kept in groups form hierarchies in which only the dominant females usually breed successfully (Olsen 1982). Fighting occurs primarily among males, with the highest incidence of injuries observed at the beginning of the main September-March breeding season (Olsen 1980, 1982). The results of trapping studies indicate that population density may vary considerably, with the greatest numbers of animals typically occupying man-modified habitats such as irrigation channels or fish farms (McNally 1960, Watts and Aslin 1981, Smales 1984). Aggressive behaviour appears to be related to pelage colour (phenotype) and population density; the higher the density the greater the number of injured individuals (Olsen 1980).

Reduced cannibalism during male pregnancy

Behaviour ◽  
2016 ◽  
Vol 153 (1) ◽  
pp. 91-106 ◽  
Author(s):  
M. Cunha ◽  
A. Berglund ◽  
T. Alves ◽  
N.M. Monteiro
Keyword(s):  
Post Partum ◽  
Feeding Activity ◽  
Filial Cannibalism ◽  
Fitness Costs ◽  
Life History Stages ◽  
In The Wild ◽  
Males And Females ◽  
Male Pregnancy ◽  
Time And Energy ◽  
Benefits And Costs

Cannibalism provides energetic benefits but is also potentially costly, especially when directed towards kin. Since fitness costs increase with time and energy invested in offspring, cannibalism should be infrequent when parental investment is high. Thus, filial cannibalism in male syngnathids, a group known for the occurrence of male pregnancy, should be rare. Using the pipefish (Syngnathus abaster) we aimed to investigate whether cannibalism does occur in both sexes and how it is affected by reproductive and nutritional states. Although rare, we witnessed cannibalism both in the wild and in the laboratory. Unlike non-pregnant males and females, pregnant and post-partum males largely refrained from cannibalising juveniles. Reproducing males decreased their feeding activity, thus rendering cannibalism, towards kin or non-kin, less likely to occur. However, if not continuously fed, all pipefish adopted a cannibal strategy, revealing that sex and life history stages influenced the ratio between the benefits and costs of cannibalism.

Preliminary observations on factors affecting foraging activity in the limpet Patella vulgata

1990 ◽  
Vol 70 (1) ◽  
pp. 181-195 ◽  
Author(s):  
Colin Little ◽  
David Morritt ◽  
David M. Paterson ◽  
Penny Stirling ◽  
Gray A. Williams
Keyword(s):  
Relative Humidity ◽  
Heavy Rainfall ◽  
Feeding Activity ◽  
Activity Patterns ◽  
High Water ◽  
Irish Sea ◽  
Foraging Activity ◽  
Factors Affecting ◽  
Calm Water ◽  
Lough Hyne

Activity patterns of limpets were studied at two adjacent sites in an Irish sea lough, Lough Hyne, in order to relate timing of activity to physical and biological influences. Activity was suppressed during heavy rainfall, and osmotic stress from dilution appears to have led to increased mortality in transplanted limpets. Activity increased as tides progressed from neaps to springs, and for limpets low on the shore it was enhanced by wave action. It is suggested that lack of activity in calm water may reduce predation pressure from crabs, which caused high mortality in transplanted limpets. Either low relative humidity or dryness of the rock diminished activity of low-water limpets. Differences in feeding activity between low-water limpets and high-water limpets may relate to food supply, since more food was available low on the shore, and the guts of low-water limpets contained more diatoms than those of high-water individuals. Differences between the two sites are at present unexplained but may relate to differences in micro habitats.

Remote monitoring of the behaviour and activity of captive southern hairy-nosed wombats (Lasiorhinus latifrons)

2009 ◽  
Vol 31 (2) ◽  
pp. 123 ◽  
Author(s):  
Lindsay A. Hogan ◽  
Clive J. C. Phillips ◽  
Allan Lisle ◽  
Alan B. Horsup ◽  
Tina Janssen ◽  
...  
Keyword(s):  
Circadian Rhythm ◽  
Video Surveillance ◽  
Remote Monitoring ◽  
Activity Patterns ◽  
Behavioural Ecology ◽  
Radio Transmitter ◽  
Rest Periods ◽  
In The Wild ◽  
Radio Transmitters ◽  
One Year

The nocturnal nature of wombats makes it difficult to learn about their behavioural ecology and activity rhythms in the wild. A facility was established at Rockhampton Zoo to house 12 adult southern hairy-nosed wombats in order to monitor their behaviour by means of video surveillance and provide detailed information on their activity patterns using movement-sensitive radio-transmitters. After one year of monitoring it was established that the wombats spent, on average, as a proportion of total time 69.9% sleeping, 8.8% lying resting, 5.2% feeding, 5.2% exploring, 4.3% performing stereotyped behaviour, 2.5% sitting resting and 4.1% in other activities. Feeding, lying resting and sleeping varied with season by ~5%. Temporal patterns were bimodal for 8 of the 12 behaviours described, with most ‘active’ behaviours being expressed between 1800 and 2000 hours and 0200 and 0500 hours. The activity pattern was characterised by a strong circadian rhythm, with most activity occurring nocturnally. Within active periods there was an alternating rhythm of active and rest periods and activity peaks at the beginning and end of each night. Comprehensive and reliable information on the behavioural ecology, as well as captive management, of southern hairy-nosed wombats was obtained from the remote video and radio-transmitter recordings.

Feeding strategies during the lactation period for first-parity sows

1995 ◽  
Vol 75 (3) ◽  
pp. 461-467 ◽  
Author(s):  
M. Genest ◽  
S. D'Allaire
Keyword(s):  
Feed Intake ◽  
Average Daily Gain ◽  
Feed Consumption ◽  
Feeding Strategies ◽  
Lactation Period ◽  
Feeding Frequency ◽  
Body Reserves ◽  
Feeding Regimes ◽  
High Feed ◽  
Meal Time

The effects of different feeding regimes during the lactation period on feed intake, body reserves and sow performance were evaluated. A 2 × 2 factorial design was used and 183 first-parity sows were randomly allocated to one of four treatments: sows were fed either two or three meals per day with (wet feed) or without (dry feed) supplemental water at meal time. Primrparous sows were fed ad libitum 12–16 h after parturition. The addition of water at meal time increased (P < 0.01) feed consumption by 5% over the 18-d lactation period. Increased feeding frequency did not influence feed intake. During the first week of lactation, most sows gained weight, but thereafter lost weight, with the rate of weight loss reaching a peak during the last week of lactation. Although feed intake was influenced only by wet feeding, both an increased frequency of daily meals and the use of wet feeding reduced mobilization of body reserves. Wet-fed sows lost less weight than dry-fed sows and the increased feeding frequency reduced backfat loss. Average daily gain of piglets, percentage of sows with a weaning-to-estrus interval of less than 7 d, farrowing rate, and parity-2 litter size were similar among the four groups. A lack of significant improvement in sow performance with different regimes may be partly related to a generally high feed intake and minimal weight and backfat losses. Although our results failed to show a benefit on sow performance, we believe that some of the feeding strategies evaluated could be useful during periods in which sows eat less, such as in the summer, or in some herds that have feed consumption problems. Key words: Sow, feed intake, weight, backfat, reproductive performance

Diurnal and nocturnal feeding activity in Arctic char (Salvelinus alpinus) and rainbow trout (Oncorhynchus mykiss)

1997 ◽  
Vol 54 (12) ◽  
pp. 2894-2900 ◽  
Author(s):  
Anders Alanärä ◽  
Eva Brännäs
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Salvelinus Alpinus ◽  
Feeding Activity ◽  
Activity Patterns ◽  
Arctic Char ◽  
Diel Activity ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Nocturnal Feeding ◽  
Nocturnal Fish

When food is limited and competition for it is high, individual fish may adopt different diel activity patterns. We followed individual feeding activity in groups of 10 Arctic char (Salvelinus alpinus) and rainbow trout (Oncorhynchus mykiss) using a combined self-feeding and PIT-tag system. Food was supplied at low and high rewards to five replicate groups of Arctic char and rainbow trout. Four categories were identified in both species: high-triggering diurnal (diurnal fish with the highest self-feeding activity), low-triggering diurnal, nocturnal, and nontriggering fish. On average, the photophase proportion of the total daily activity was approx 90% in diurnal and approx 20% in nocturnal individuals. Rainbow trout offered high rewards did not show any diel preferences. Diurnal Arctic char and rainbow trout with the highest self-feeding activity were initially larger and had the highest growth rates, indicating a high social position. Nocturnal fish were initially smaller and their proportion of trigger actuations much lower than the high-triggering diurnal fish. These still grew successfully whereas nontriggering fish grew significantly less. Thus, some individuals with a low social status may apply an alternative strategy to attain adequate growth by feeding at night when dominant individuals are less aggressive. This may be referred to as concurrent dualism (diurnalism and nocturnalism).

scholarly journals A review of the impacts of salmonid farming on marine coastal ecosystems in the southeast Pacific

2006 ◽  
Vol 63 (7) ◽  
pp. 1338-1345 ◽  
Author(s):  
Alejandro H. Buschmann ◽  
Verónica A. Riquelme ◽  
María C. Hernández-González ◽  
Daniel Varela ◽  
Jaime E. Jiménez ◽  
...  
Keyword(s):  
Native Species ◽  
Chemical Properties ◽  
Ecosystem Approach ◽  
Coastal Ecosystems ◽  
Significant Loss ◽  
Current Evidence ◽  
Farmed Fish ◽  
Physico Chemical ◽  
In The Wild ◽  
Farming Industry

Abstract The production of farmed salmonids in Chile reached 550 000 t in 2004. The industry is considered to be consolidated, but with potential for further expansion to the south into pristine coastal areas. The environmental impacts of the salmonid farming industry in Chile were reviewed in 1996, and evidence at that time did not suggest significant adverse effects. However, after almost ten years of sustained growth, current evidence indicates that significant loss of benthic biodiversity and localized changes in the physico-chemical properties of sediments have occurred in areas with salmonid farms. Furthermore, the presence of these farms significantly increases in pulses the density of dinoflagellates. Data suggest that escaped farmed fish may have an impact on native species, although their survival in the wild appears low. The abundance of omnivorous diving and carrion-feeding marine birds increased from twofold to fivefold in areas with salmon farms compared with control areas without them. It is urgent that an ecosystem approach be implemented to assess all impacts of salmonid farming on coastal ecosystems in southern Chile.

scholarly journals Reproductive Behaviors of Wild Chinese Pangolin (Manis Pentadactyla): A Case Study Based on Long-Term Monitoring

2021 ◽  
Author(s):  
Nick Ching-Min Sun ◽  
Kurtis Jai-Chyi Pei ◽  
Li-Yue Wu
Keyword(s):  
Maternal Separation ◽  
Post Partum ◽  
Activity Patterns ◽  
Camera Traps ◽  
Adult Males ◽  
Reproductive Behaviors ◽  
In The Wild ◽  
Manis Pentadactyla ◽  
History Of ◽  
Almost All

Abstract Observations of Chinese pangolin (Manis pentadactyla) in the wild are extremely rare and challenging because of their nocturnal and cryptic activity patterns and low population density. The present article reported the first field observation in eastern Taiwan, from October 4, 2012 to June 16, 2016, on the reproductive behavior of the Chinese pangolin based on the monitoring of a female (LF28) using radiotelemetry and camera traps. During this period, LF28 aged from 1 to 4.5-years old and gave two single-births, both took place in early December, at 3 and 4 years old, respectively. We recorded the entire 157 days of the first nursing period from parturition to maternal separation. For the second infant, the gestation period was estimated to be around 150 days based on the evidence that the pregnancy started in early Jul. 2015 and the offspring was born on Dec. 9, 2015. During the entire nursing period, LF28 frequently moved the offspring from one nursing burrow to another staying various durations ranging from 1 day to more than 35 days, and almost all (= 15/16) of these burrows were located in the core (MCP75) of LF28’s home range. Started from the month of parturition and lasting throughout the whole nursing period, different adult males constantly visiting the nursing burrows were recorded. Mating behavior was recorded once outside the burrow in March, which provided evidence of the occurrence of post-partum estrus in this species. Delay implantation was proposed based on the observation of a several months lag between copulation and the estimated pregnancy initiation date. The present study demonstrated the advantage of using remote technologies to learn the life history of resting fossorial species.

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