Estimation of Total Length from Head Length of Saltwater Crocodiles (Crocodylus porosus) in the Northern Territory, Australia

2013 ◽  
Vol 47 (1) ◽  
pp. 34-40 ◽  
Author(s):  
Yusuke Fukuda ◽  
Keith Saalfeld ◽  
Garry Lindner ◽  
Tom Nichols
Keyword(s):  
Northern Territory ◽  
Head Length ◽  
Total Length ◽  
Crocodylus Porosus

scholarly journals Morphometric characters and their relationship in estuarine catfish

1970 ◽  
Vol 6 (2) ◽  
pp. 349-353 ◽  
Author(s):  
M Begum ◽  
Abdullah Al-Mamun ◽  
ML Islam ◽  
MJ Alam
Keyword(s):  
Sexual Dimorphism ◽  
Linear Relationship ◽  
Standard Length ◽  
Head Length ◽  
Pectoral Fin ◽  
Morphometric Characters ◽  
Total Length ◽  
Length Standard ◽  
Eye Diameter ◽  
Males And Females

The morphometric observations were made on total length, standard length, pre-caudal length, head length, eye diameter and depth of body at pectoral fin base of estuarine catfish M. gulio. Males and females showed homogeneity in characters. A linear relationship was found between total length and morphometric characters. Regression of length and weight did not deviate significantly from cube law indicating isometric growth. The fish exhibited sexual dimorphism. Keywords: Morphometric characters; Estuarine catfish; Mystus gulio DOI: 10.3329/jbau.v6i2.4833 J. Bangladesh Agril. Univ. 6(2): 349-353, 2008

Problem crocodiles, Crocodylus porosus, at Nhulunbuy, Northern Territory: an assessment of relocation as a mangaement strategy

1993 ◽  
Vol 20 (1) ◽  
pp. 127 ◽  
Author(s):  
B Walsh ◽  
PJ Whitehead
Keyword(s):  
Carrying Capacity ◽  
Northern Territory ◽  
Effective Strategy ◽  
Wet Season ◽  
Rates Of Return ◽  
Saltwater Crocodile ◽  
Crocodylus Porosus ◽  
Remote Sites ◽  
Total Capture ◽  
Capture Rates

Since 1986 the Conservation Commission of the Northern Territory has operated a programme to remove 'problem' saltwater crocodiles from waters in and adjoining the township of Nhulunbuy. Over a period of five years, 52 different saltwater crocodiles (44 male) were captured. Most (48) were released at remote sites designated by the traditional Aboriginal owners of the surrounding lands. Release distances from the township varied from 17 to 282 km (by coastline). Many crocodiles (47.9%), including those released at the most distant sites, returned to, and were subsequently recaptured at, the township. Total capture rates (initial captures and recaptures pooled) varied seasonally, with fewer crocodiles being caught in the cooler dry season. During the wet season capture rates remained high, but relatively fewer 'new' crocodiles were caught. Probability of recapture could not be related to distance and direction of release from the township, nor size and sex of the released crocodile. Frequency of capture of individual crocodiles (1-8 times) was also unrelated to these variables. The high rates of return indicate that relocation is unlikely to be an effective strategy for managing humancrocodile interactions, at least in areas where potential release sites already support saltwater crocodile populations near carrying capacity.

scholarly journals Morphometry of Rhinomugil Corsula (Hamilton, 1822) From Sitakunda Coast of the Bay of Bengal, Bangladesh

2021 ◽  
Vol 49 (2) ◽  
pp. 229-241
Author(s):  
Syeda Ismat Ara ◽  
Mohammad Ali Azadi ◽  
Munira Nasiruddin ◽  
Aftab Hossain
Keyword(s):  
Bay Of Bengal ◽  
The Body ◽  
Head Length ◽  
Regression Equations ◽  
Morphometric Characters ◽  
Total Length ◽  
Linear Relationships ◽  
Investigation Period ◽  
R Value ◽  
Rhinomugil Corsula

A total of 65 specimens of Rhinomugil corsula (Hamilton, 1822), measuring from 8.1 cm to 28.9 cm in total length, collected from the Sitakunda coast of the Bay of Bengal, were used for the morphometric analysis during the period between March 2016 and February 2018. Twenty seven morphometric characters were selected and studied during the investigation period. The regression equations – both arithmetic and logarithmic – between the total length (TL) and 21 morphometric characters, and head length (HL) with five morphometric characters related to the head, were determined. The value of coefficient of correlation ‘r’ for each relationship was calculated and t-test for each ‘r’ value was also done. The relationships of the various measurements of the body with the total length – and head length with the five relevant characters -of R. corsula from the Sitakunda coast of the Bay of Bengal showed linear relationships, which were highly significant (P<0.01). The ranges of ‘b’ values 0.967 to 1.346 in case of the relationships between TL and 21 relevant characters, whereas 0.906 to 1.236 in case of the relationships between HL and 5 relevant characters. These values differ insignificantly (P>0.01) with typical value b=1 indicating isometric relationships among the characters. Bangladesh J. Zool. 49 (2): 229-241, 2021

Monitoring Crocodylus porosus populations in the Northern Territory of Australia: a retrospective power analysis

2001 ◽  
Vol 28 (6) ◽  
pp. 547 ◽  
Author(s):  
S. C. Stirrat ◽  
D. Lawson ◽  
W. J. Freeland ◽  
R. Morton
Keyword(s):  
Power Analysis ◽  
Northern Territory ◽  
Management Program ◽  
Survey Method ◽  
Management Information ◽  
River Systems ◽  
Pooled Data ◽  
Management Actions ◽  
Sampling Program ◽  
Crocodylus Porosus

In the Northern Territory of Australia, populations of the estuarine crocodile (Crocodylus porosus) have been subject to an annual egg harvest since the early 1980s. Since 1997, adult and juvenile crocodiles have also been harvested in some catchments. Annual surveys of crocodile populations are conducted in order to ensure that the harvest is sustainable. Boat surveys commenced in 1975 and helicopter surveys commenced in 1989. Retrospective power analysis was used to determine whether the sampling program meets the objectives of the Crocodile Management Program for the Northern Territory. Data collected during boat surveys vary in quality between river systems. The analysis of pooled data from 7 river systems with a residual standard deviation of 0.11 indicates that the power of the current spotlight survey method to detect a decline of 10% per annum in around 4 years is about 0.9. In this time the population would decline by around 33% and would fully recover in 8 years following the removal of the factor causing the decline. This allows detection of a decline within one-third, and recovery within two-thirds, of the estimated generation time of the saltwater crocodile and will allow management actions to be implemented before the impacts on populations are serious. The data from helicopter and boat surveys from a 10-year period were compared. Helicopter surveys did not provide useful management information.

Problem crocodiles(Crocodylus porosus)in the freshwater, Katherine River, Northern Territory, Australia

2011 ◽  
Vol 35 (3) ◽  
pp. 858-863 ◽  
Author(s):  
Mike Letnic ◽  
Patrick Carmody ◽  
John Burke
Keyword(s):  
Northern Territory ◽  
Crocodylus Porosus

Corrigendum to: Broad-scale environmental influences on the abundance of saltwater crocodiles (Crocodylus porosus) in Australia

2008 ◽  
Vol 35 (2) ◽  
pp. 170 ◽  
Author(s):  
Yusuke Fukuda ◽  
Peter Whitehead ◽  
Guy Boggs
Keyword(s):  
Environmental Influences ◽  
Strong Support ◽  
Northern Territory ◽  
The Other ◽  
Total Precipitation ◽  
Northern Australia ◽  
Landscape Modification ◽  
Geographical Variations ◽  
Crocodylus Porosus ◽  
Broad Scale

Saltwater crocodile (Crocodylus porosus) populations have recovered strongly across northern Australia over the 30 years since the species was protected from hunting. However, monitoring studies show large geographical variations in abundance across the Northern Territory, Queensland and Western Australia. The Northern Territory has considerably higher densities, raising questions about constraints on recovery in the other states. We examined broad-scale environmental influences on population abundance by modelling the species.environment relationships across northern Australia. The hypothesis-based models showed strong support for the linkage to (1) the ratio of total area of favourable wetland vegetation types (Melaleuca, grass and sedge to total catchment area, (2) a measure of rainfall seasonality, namely the ratio of total precipitation in the coldest quarter to total precipitation in the warmest quarter of a year, and (3) the mean temperature in the coldest quarter of a year. On the other hand, we were unable to show any clear negative association with landscape modification, as indicated by the extent of high-impact land uses or human population density in catchments. We conclude that geographical variations in crocodile density are mostly attributable to differences in habitat quality rather than the management regimes adopted in the respective jurisdictions.

scholarly journals Thermic Variation in Incubation and Development of Pantanal Caiman (Caiman crocodilus yacare) (Daudin, 1802) Kept in Metabolic Box

2002 ◽  
Vol 45 (3) ◽  
pp. 333-342 ◽  
Author(s):  
Maristela Parra Miranda ◽  
Gentil Vanini de Moraes ◽  
Elias Nunes Martins ◽  
Luis Carlos Pinto Maia ◽  
Orlando Rus Barbosa
Keyword(s):  
Regression Analysis ◽  
Tail Length ◽  
Head Length ◽  
Head Width ◽  
Snout Length ◽  
Temperature Range ◽  
Caiman Crocodilus ◽  
Total Length

Thirty-two eggs of Pantanal caiman (Caiman crocodilus yacare) (Daudin, 1802) were incubated at 30° C. After 20 days of incubation at 30° C, the remaining eggs were distributed in the following way: seven at 34° C, seven at 32° C, six at 30° C and six at 28° C. At 32° C and 34° C a 100% hatchability was obtained while at 30° C 83.3% and at 28° C 66.6%. After hatching, the animals were kept for 120 days at the same temperature of their final incubation. Weight (g) control and morphometric (cm) analysis were carried out. The statistic design was totally randomized and the data were treated by regression analysis showing a quadratic behavior ( p<0.05). It was found that weight, total length (TTL), tail length (TL), snout- vent length (SVL), head length (HL), eye length (EL), snout length (SL), mid-point snout width (MSW), head width (HW), width of snout at nostrils (NW), distance between limbs (DBL) showed a higher development at the temperature range from 31.2° C to 31.8° C and circumference of belly at 30.0° C.

scholarly journals Morphometric and meristic characters of snow trout, Schizothorax labiatus, inhabiting the Jhelum River and its tributaries

2020 ◽  
Vol 28 (4) ◽  
pp. 216-224
Author(s):  
Kousar Jan ◽  
Imtiaz Ahmed
Keyword(s):  
Fish Species ◽  
Fork Length ◽  
Head Length ◽  
Meristic Characters ◽  
Morphometric Characters ◽  
Total Length ◽  
Linear Relationships ◽  
Jhelum River ◽  
High Degree ◽  
Management And Conservation

Abstract Schizothorax labiatus (McClelland) is considered to be one of the most economically important fish species among Schizothorax spp. A total of twenty-four morphometric and five meristic characters were examined; 18 of the morphometric characters as percentages of total length and four characters as percentages of head length were studied. It was found that the characters of standard length, fork length, pre pelvic length, pre anal length, and pre dorsal length had the highest correlations with total length, whereas dorsal fin height followed by caudal fin height had the lowest correlations. In percentages of head length post orbital length had the highest correlation whereas snout length had the lowest correlation. Overall, the results revealed that all the morphometric characters exhibited linear relationships and depicted significantly (P < 0.05) high degree of correlation, while the meristic characters counted were constant in all sizes of S. labiatus, indicating that they were independent of body size. The study provided basic information that will be useful for fish biologists and researchers in the future management and conservation of this fish species.

scholarly journals Some Aspects of Biology of Chola Punti Puntius Chola (Hamilton) from the Kangsa River

1970 ◽  
Vol 45 (4) ◽  
pp. 309-314
Author(s):  
Bi K Saha ◽  
A Saha
Keyword(s):  
Sex Ratio ◽  
Standard Length ◽  
Condition Factor ◽  
Fork Length ◽  
Head Length ◽  
Mean Values ◽  
Snout Length ◽  
Total Length ◽  
Relative Condition Factor ◽  
The Mean

The mean values of total length (75.89 ± 13.09 mm), standard length (54.98 ± 7.07 mm), fork length (60.86 ± 9.14 mm), head length (14.75 ± 2.05 mm), snout length (3.79 ± 0.61 mm), pre-dorsal length (31.53 ± 3.18 mm), height of body (20.2 ± 4.11 mm) and total weight (6.62 ± 3.55g) of combined sex of Puntius chola were calculated. Relationships between total length and standard length, fork length, head length, snout length and pre-dorsal length of Puntius chola were found to be linear, positive and highly significant. The length-weight relationship in male, female and combined sex were determined as Log W=-4.510+2.810 Log L, LogW=-4.204+2.685 Log L and Log W=4.465+2.808 Log L respectively. The mean values of condition factor from observed value (ko) of male, female and combined sex were determined as 1.36 ± 0.089, 1.599 ± 0.181 and 1.515 ± 0.192 respectively. The mean values of condition factor from calculated value (kc) of male, female and combined sex were found to be 1.362 ± 0.054, 1.6 ± 0.124 and 1.511 ± 0.075 respectively. The mean values of relative condition factor of male, female and combined sex were registered as 0.999 ± 0.044 , 0.999 ± 0.064 and 0.999 ± 0.112 respectively. Sex ratio was found to be 1:1. Key words: Standard length; Pre-dorsal length; Puntius chola; Morphomertric; Fish culture. DOI: 10.3329/bjsir.v45i4.7327 Bangladesh J. Sci. Ind. Res. 45(4), 309-314, 2010

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