The effects of age and length on homing performance in the intertidal cottid, Oligocottus maculosus Girard

1981 ◽  
Vol 59 (4) ◽  
pp. 598-604 ◽  
Author(s):  
G. J. S. Craik
Keyword(s):  
Home Range ◽  
Age Groups ◽  
Considerable Variability ◽  
Size Classes ◽  
Homing Behaviour ◽  
Total Length ◽  
Homing Performance ◽  
Oligocottus Maculosus

The intertidal cottid Oligocottus maculosus Girard has been previously reported to demonstrate homing behaviour, that is, to return to its home range (group of tidepools covered in normal travel) and (or) its home pool (pool of first capture) when transplanted to a pool some distance away. Investigation of significant differences in homing behaviour between the three major age groups of O. maculosus showed an improvement in the percentage successfully homing with length, peaking between 5 and 7 cm (total length) (age 2), with considerable variability in smaller size classes and decreasing homing success in larger fish.Juvenile fish (about 2.3 to 2.7 cm) move extensively between tidepools and begin demonstrating home range fidelity and homing behaviour at about 3 cm. It is suggested that during this period of extensive movement, the area is in some way "learned" and "memorized."

scholarly journals Decreased stock entering the Belgian Meuse is associated with the loss of colonisation behaviour in yellow-phase European eels

2018 ◽  
Vol 31 ◽  
pp. 7 ◽  
Author(s):  
Billy Nzau Matondo ◽  
Michaël Ovidio
Keyword(s):  
Home Range ◽  
Water Temperature ◽  
River Flow ◽  
Upstream Migration ◽  
Migratory Behaviour ◽  
Pit Tag ◽  
Size Classes ◽  
Total Length ◽  
Vertical Slot ◽  
Inland Rivers

The upstream migratory behaviour of yellow-phase European eels was investigated in regulated inland rivers (>320 km upstream the sea), where the stock is in drastic decline. From 2010 to 2015, eels entering the Belgian Meuse River (n = 1357; total length, 231–755 mm) were caught in fish passes, tagged with a pit-tag and released. Their upstream movements were tracked during the next six consecutive years, using three detection stations installed in vertical-slot fish passes of the Meuse and its Ourthe tributary. Among the 1357 eels tagged, 27.6% (n = 374 individuals) were detected at one or more of the three upstream detection stations. Only 6.6% (n = 89) of tagged eels were detected at the two subsequent stations. In this last group, most of the detected eels continued to move upstream through the Meuse rather than leaving it for the Ourthe. Water temperature >13 °C, river flow 24–226 m3/s, dark time 00:00–05:00 h and the spring–summer seasons were the most important cues for upstream migration. Temperatures and flows at detection did not differ between size classes of ascending eels, while the detection period was earlier and daily speed was faster in large (>450 mm) eels. However, small (≤300 mm) eels moved further upstream at slow speeds because they alternated between short periods of movement and long stationary periods. This behaviour suggests the existence of a few nomad individuals and probably more home range dwellers in the entering population. Small eels were better suited to colonise upper rivers.

scholarly journals Homing behaviour of pigeons subjected to unilateral zinc sulphate treatment of their olfactory mucosa

1996 ◽  
Vol 199 (11) ◽  
pp. 2531-2535 ◽  
Author(s):  
S Benvenuti ◽  
A Gagliardo
Keyword(s):  
Brain Damage ◽  
Zinc Sulphate ◽  
Experimental Treatment ◽  
Olfactory Mucosa ◽  
Initial Orientation ◽  
Sulphate Solution ◽  
Control Groups ◽  
Homing Behaviour ◽  
Homing Performance ◽  
Zinc Sulphate Solution

Pigeons were made anosmic by unilateral treatment of their olfactory mucosa with a zinc sulphate solution and by plugging the contralateral nostril. In a series of releases at unfamiliar sites, 55­79 km from the home loft, the experimental birds' homing behaviour was compared with that of two control groups: unmanipulated control birds, and birds subjected to unilateral zinc sulphate treatment and equipped with an ipsilateral nasal plug. The experimental pigeons exhibited homing behaviour ­ in terms of both homeward initial orientation and homing performance ­ significantly poorer than that of both unmanipulated and treated control pigeons. In addition, the homing behaviour of the treated controls turned out to be only slightly, and not significantly, poorer than that of the unmanipulated birds. The results show that the impaired homing capabilities of the zinc-sulphate-treated birds are due to the lack of navigational information and not to non-specific brain damage caused by the experimental treatment.

High Tide Movements and Homing Behaviour of the Tidepool Sculpin Oligocottus maculosus

1971 ◽  
Vol 28 (3) ◽  
pp. 383-389 ◽  
Author(s):  
John M. Green
Keyword(s):  
Spatial Distribution ◽  
Intertidal Zone ◽  
High Tide ◽  
Homing Behavior ◽  
Homing Behaviour ◽  
Oligocottus Maculosus

Tagging studies show that the tidepool sculpin Oligocottus maculosus Girard shows fidelity to specific tide pools and will return to their pools when displaced. The results indicate that the navigational ability of O. maculosus is not solely dependent upon familiarity with geographical features of the intertidal zone. It is suggested that homing behavior functions as a mechanism stabilizing the spatial distribution of this species.

Maturation and Fecundity of Brook Trout from Infertile Streams

1966 ◽  
Vol 23 (5) ◽  
pp. 623-649 ◽  
Author(s):  
Richard S. Wydoski ◽  
Edwin L. Cooper
Keyword(s):  
Brook Trout ◽  
Age Groups ◽  
Reproductive Rate ◽  
Seasonal Development ◽  
Age Group ◽  
Group Iii ◽  
Total Length ◽  
Group I ◽  
Reproductive Rates ◽  
Curvilinear Regression

The reproductive rate of brook trout populations from infertile Pennsylvania streams was determined. The standing crops for eight streams varied between 14 and 41 lb/acre. Trout in age-groups 0 through III were found to grow slowly with very few individuals reaching a total length of 6 inches.The seasonal development of ova was determined by measuring all ova larger than 0.2 mm from selected females. The maturing ova of most females of age-groups II and III increased in diameter from 0.9 mm in February to 1.0 mm in June, 1.75 mm in July, 2.5 mm in August, 3.0 mm in September, and 4.0 mm in October. Maturing females could be distinguished from immature females by late August or early September on the basis of ova diameters. The mean diameter of ripe ova from 67 females was 4.05 mm with a range between 3.37 and 5.01 mm for individual trout ranging from 4.6 to 8.6 inches total length.The relationship between the number of mature ova and the total length of the female for one population was described by a curvilinear regression (log Y = −0.5361 + 3.23 log X, where Y = number of eggs, and X = the total length of the fish) for brook trout between 3.6 inches (18 eggs) and 7.7 inches (213 eggs). Variation in this relationship existed among streams.Ova production was estimated as 9050 ova per acre for one population and 13,620 ova per acre for another. Age-group-I females contributed approximately 9% of this production; age-group-II females, 54%; and age-group-III females, 37%. An ecological life table was constructed for two populations comparing rates of survival, age-specific fecundity rates, and reproductive rates.

scholarly journals Breeding strategy of Acrossocheilus fasciatus in the Puxi Stream of the Huangshan Mountain

2009 ◽  
Vol 55 (5) ◽  
pp. 350-356 ◽  
Author(s):  
Yunzhi Yan ◽  
Lili Guo ◽  
Xiuying Xiang ◽  
Yilong Xi ◽  
Yifeng Chen
Keyword(s):  
Sexual Maturity ◽  
Development Process ◽  
Age Groups ◽  
Adaptive Strategies ◽  
Breeding Strategy ◽  
Total Length ◽  
Monthly Changes ◽  
Huangshan Mountain ◽  
Minimum Total Length ◽  
Somatic Index

Abstract Breeding strategies of Acrossocheilus fasciatus were studied from 592 specimens collected monthly during May 2007 and April 2008 in the Puxi Stream of the Huangshan Mountain. Sex ratio of the studied population was 0.90 : 1 (♀ : ♂), not significantly different from 1:1. Both sexes reached their first sexual maturity at age 2 (the second calendar year of their birth). Fifty percent of females and males reached maturity at a total length of 69.75 mm and 69.36 mm respectively, and the minimum total length was 61.54 mm and 58.96 mm, respectively. Based on the monthly changes in gonado-somatic index and egg-development process, the breeding season of the population was from May to August, with one obvious interval (in June) occurring in the breeding activity for the females. The nonsynchronous development of oocytes observed in mature ovaries indicated that A. fasciatus is a batch spawner. Absolute fecundity of A. fasciatus ranged from 308 to 2002 eggs with a mean of 857 eggs, increased significantly with total length, and was significantly different among three age groups. Relative fecundity ranged from 38.63 to 71.70 egg/g with a mean of 53.29 egg/ g, and was not significantly different among the three age groups. It was suggested that these reproductive characteristics were adaptive strategies for A. fasciatus to acclimatize to lotic water where environmental factors were unstable but predictable.

scholarly journals Movement and Home Range of Nile Crocodiles in Ndumo Game Reserve, South Africa

Koedoe ◽  
2015 ◽  
Vol 57 (1) ◽  
Author(s):  
Peter M. Calverley ◽  
Colleen T. Downs
Keyword(s):  
South Africa ◽  
Home Range ◽  
Satellite Telemetry ◽  
Movement Patterns ◽  
Breeding Site ◽  
Water Levels ◽  
Home Ranges ◽  
Total Length ◽  
Game Reserve ◽  
Nile Crocodile

The study of movement patterns and home range is fundamental in understanding the spatial requirements of animals and is important in generating information for the conservation and management of threatened species. Ndumo Game Reserve, in north-eastern KwaZulu-Natal, bordering Mozambique, has the third largest Nile crocodile (Crocodylus niloticus) population in South Africa. Movement patterns of 50 Nile crocodiles with a total length of between 202 cm and 472 cm were followed over a period of 18 months, using mark-resight, radio and satellite telemetry. The duration of radio transmitter attachment (131 ± 11.4 days) was significantly and negatively related to total length and reproductive status. Satellite transmitters failed after an average of 15 ± 12.5 days. Home range was calculated for individuals with 10 or more radio locations, spanning a period of at least 6 months. There was a significant relationship between home range size and total length, with sub-adults (1.5 m – 2.5 m) occupying smaller, more localised home ranges than adults (> 2.5 m). The largest home ranges were for adults (> 2.5 m). Home ranges overlapped extensively, suggesting that territoriality, if present, does not result in spatially discrete home ranges of Nile crocodiles in Ndumo Game Reserve during the dry season. Larger crocodiles moved farther and more frequently than smaller crocodiles. The reserve acts as a winter refuge and spring breeding site for an estimated 846 crocodiles, which also inhabit the Rio Maputo during the summer months. Nile crocodile movement out of the reserve and into the Rio Maputo starts in November and crocodiles return to the reserve as water levels in the floodplain recede in May.Conservation implications: Movement patterns of Nile crocodiles show the important role the reserve plays in the conservation of Nile crocodile populations within the greater Ndumo Game Reserve–Rio Maputo area.

Visibility Distance of Highway Signs among Young, Middle-Aged, and Older Observers: Icons Are Better than Text

1990 ◽  
Vol 32 (5) ◽  
pp. 609-619 ◽  
Author(s):  
Theresa J. Babbitt Kline ◽  
Laura M. Ghali ◽  
Donald W. Kline ◽  
Steven Brown
Keyword(s):  
Age Differences ◽  
Age Groups ◽  
Considerable Variability ◽  
Middle Aged ◽  
Lighting Conditions ◽  
Visibility Distance ◽  
Highway Signs ◽  
Better Than

The visibility distances for young, middle-aged, and elderly observers of text and icon versions of four different highway signs were compared under day and dusk lighting conditions. No age differences were observed. Icon signs, however, were visible at much greater distances than were text signs for all three age groups, a difference that was more pronounced under dusk conditions. There were no age differences in the comprehension of icon signs, but there was considerable variability from one icon sign to another in the degree to which they were comprehended. Acuity was found to be a better predictor of the visibility distance of text signs in both day and dusk conditions than it was of icon signs. To the degree that they are comprehended, icon signs appear to offer drivers of all ages almost twice as much time in which to respond to them.

Home Range and Excursive Post-breeding Movements of Eurasian Eagle-Owls Revealed by GPS Satellite Transmitters

2021 ◽  
Author(s):  
Oddvar Heggøy ◽  
Tomas Aarvak ◽  
Peter Sjolte Ranke ◽  
Roar Solheim ◽  
Ingar Jostein Øien
Keyword(s):  
Home Range ◽  
Satellite Telemetry ◽  
Age Groups ◽  
Space Use ◽  
Home Range Size ◽  
Ranging Behavior ◽  
Gps Satellite Telemetry ◽  
Eagle Owl ◽  
Breeding Seasons ◽  
Management And Conservation

ABSTRACT Investigating space use of wild birds provides important knowledge of bird behavior and ecology, which is crucial in the management and conservation of threatened species. In the present study, we used GPS satellite telemetry to investigate space use and movements of seven adult Eurasian Eagle-Owls (Bubo bubo) in Norway during breeding and post-breeding seasons. Breeding adults had a mean home range size of 42.9 km2 (SD ± 35.1 km2; 95% kernel density estimation Had hoc), and five individuals performed long (>20 km) excursive movements away from their breeding territories during autumn. Such wide-ranging behavior has not previously been reported for adults of the nominate subspecies B. b. bubo. The study demonstrates the need to investigate seasonal movements of species, populations, and age groups even if they are considered residents, and provides valuable information for management and conservation of the Eurasian Eagle-Owl.

THE NUMERICAL DISTRIBUTION OF THE ISLETS OF LANGERHANS AT DIFFERENT AGES OF THE RAT

1959 ◽  
Vol XXXII (I) ◽  
pp. 63-77 ◽  
Author(s):  
Bo Hellman
Keyword(s):  
Islets Of Langerhans ◽  
Age Groups ◽  
Relative Increase ◽  
Size Class ◽  
Size Classes ◽  
Surface Areas ◽  
Different Ages ◽  
Proportional Increase ◽  
Mathematical Relationships ◽  
Made In

ABSTRACT The mathematical relationships between the observed size distribution of the section surfaces and the actual distributions of different sized spherical and ellipsoidal bodies, postulated by Wicksell (1925, 1926) have been used to determine the numerical distributions of the islets of Langerhans in rats of different ages. Only those islets whose surface areas in the section were equal to or exceeded that of a standard circle 46.9 μ in diameter were included in the measurements. New-born rats and rats 5, 21, 100 and 480 days old were studied. The numerical distribution curves at all ages appeared asymmetrical with the smallest islets predominating. With an increased number of islets the largest size classes in general showed the greatest proportional increase both when the comparison was made in the same and between different age groups. A very high proportion of the islets studied could be arranged in the same regular pattern. In all the animals the relation between the logarithms of the islet numbers and their diameters was linear in those of the size classes studied, which contributed significantly to the total number of islets. Since the lines for any age group and the next were also approximately parallel the relative increase in the number of islets in any size class (except the very largest with only few islets) was thus nearly constant, i. e. independent of the particular size class. In comparing rats within the same or between two succeeding age groups the nearly parallel lines allow both the islet number in each of the size classes mentioned above and the total number of islets to be characterized by a parameter Lm which is the value of the line at its intercept on the Y axis.

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