A Model for Standardizing Dungeness Crab (Cancer magister) Catch Rates among Traps which Experienced Different Soak Times

1989 ◽  
Vol 46 (9) ◽  
pp. 1600-1608 ◽  
Author(s):  
Barry D. Smith ◽  
Glen S. Jamieson
Keyword(s):  
Frequency Distribution ◽  
Dungeness Crab ◽  
Entry And Exit ◽  
Agonistic Interactions ◽  
Cancer Magister ◽  
Size Frequency Distribution ◽  
Catch Rates ◽  
Dungeness Crabs ◽  
Index Of Abundance ◽  
Over Time

The abundance and size frequency distribution (SFD) of Dungeness crabs (Cancer magister) within traps varies with soak time. Such bias in catch rates was reduced using a standardization model that corrected for (1) changes in bait effectiveness over time and (2) agonistic interactions between crabs within traps and those attempting entry. The model estimated the entry and exit of crabs based on the results of trapping experiments specifically designed to (1) emphasize the above two processes and (2) estimate escapement rates from traps for crabs of different sizes. Results clearly indicated the importance of these two processes in modifying trap contents over time, and led to the introduction of the term 'virtual catch rate' (VCR), defined as the rate at which crabs would enter a trap if catch rates did not change with increasing soak time. VCRs are not observed in practice except perhaps for very short soak times, but can be estimated from trap samples by incorporating the aforementioned processes into a standardization model. We found VCR to be a better index of abundance than mean daily catch per trap, and believe it may have utility for other trap fisheries.

Isolation and inheritance of microsatellite loci in the Dungeness crab (Brachyura: Cancridae: Cancer magister)

Genome ◽  
2004 ◽  
Vol 47 (2) ◽  
pp. 325-331 ◽  
Author(s):  
Pamela C Jensen ◽  
Paul Bentzen
Keyword(s):  
Microsatellite Loci ◽  
Pcr Amplification ◽  
Mendelian Inheritance ◽  
Descriptive Statistics ◽  
Drop Out ◽  
Dungeness Crab ◽  
Cancer Magister ◽  
Heterozygous Individual ◽  
Dungeness Crabs ◽  
Allelic Drop Out

The isolation, PCR amplification, and descriptive statistics of six microsatellite loci are described for the Dungeness crab, Cancer magister. Also reported is the inheritance of these loci in two families obtained from artificial crosses in the laboratory. All six loci conform to expectations under Mendelian inheritance and there is no evidence for linkage between any of the loci. Allelic size ranges for three of the loci are relatively large, ranging from 135–357 bp between the smallest and largest allele detected at that locus. At two of these loci upper allelic drop out (non-amplification of the larger allele in a heterozygous individual) can be problematic for scoring. Results from cross-species amplification in nine congeners are summarized. These loci will be valuable in studies requiring high-resolution genetic markers in Dungeness crabs and related species.Key words: Cancer magister, microsatellite, Mendelian Inheritance, cross species amplification, Brachyura.

Effects of Predation and Trophic Conditions on the Reproduction of Tylototriton verrucosus (Caudata: Salamandridae) in Darjeeling

2011 ◽  
Vol 4 (2) ◽  
pp. 163-169 ◽  
Author(s):  
Ritwik Dasgupta
Keyword(s):  
Frequency Distribution ◽  
Primary Productivity ◽  
Egg Size ◽  
Zooplankton Abundance ◽  
Trophic Conditions ◽  
Size Frequency Distribution ◽  
Size Frequency ◽  
High Predation ◽  
Hatchling Size ◽  
Predation Rates

The facts that small hatchlings emerged from small eggs laid under high predation levels prevailing at the lower altitudes of distribution of this species in Darjeeling while larger hatchlings emerged from larger eggs laid under lower levels of predation at higher altitudes, show that predation is not selected for large egg and initial hatchling size in this salamandrid species. Metamorphic size was small under high predation rates because this species relied on crypsis for evading predators. Egg and hatchling size are related inversely to levels of primary productivity and zooplankton abundance in lentic habitats. Hatchling sizes are related positively to egg size and size frequency distribution of zooplankton. Small egg and small hatchling size have been selected for at the lower altitudes of distribution of this salamandrid in Darjeeling because predation rates increased in step with improvement in trophic conditions at the lower altitudes.

SIZE FREQUENCY DISTRIBUTION BIASES IN HORSESHOE CRAB MOLT ASSEMBLAGES: IMPLICATIONS FOR THE FOSSIL RECORD

2016 ◽  
Author(s):  
Shelly J. Wernette ◽  
◽  
Scott Evans ◽  
Christine Hall ◽  
Mary L. Droser ◽  
...  
Keyword(s):  
Frequency Distribution ◽  
Fossil Record ◽  
Horseshoe Crab ◽  
Size Frequency Distribution ◽  
Size Frequency

scholarly journals Blocks Size Frequency Distribution in the Enceladus Tiger Stripes Area: Implications on Their Formative Processes

Universe ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 82
Author(s):  
Maurizio Pajola ◽  
Alice Lucchetti ◽  
Lara Senter ◽  
Gabriele Cremonese
Keyword(s):  
Frequency Distribution ◽  
Power Law ◽  
Size Frequency Distribution ◽  
Surface Stresses ◽  
Size Frequency ◽  
The One ◽  
Power Law Index ◽  
Comet 67P ◽  
South Polar ◽  
Degree Of Fragmentation

We study the size frequency distribution of the blocks located in the deeply fractured, geologically active Enceladus South Polar Terrain with the aim to suggest their formative mechanisms. Through the Cassini ISS images, we identify ~17,000 blocks with sizes ranging from ~25 m to 366 m, and located at different distances from the Damascus, Baghdad and Cairo Sulci. On all counts and for both Damascus and Baghdad cases, the power-law fitting curve has an index that is similar to the one obtained on the deeply fractured, actively sublimating Hathor cliff on comet 67P/Churyumov-Gerasimenko, where several non-dislodged blocks are observed. This suggests that as for 67P, sublimation and surface stresses favor similar fractures development in the Enceladus icy matrix, hence resulting in comparable block disaggregation. A steeper power-law index for Cairo counts may suggest a higher degree of fragmentation, which could be the result of localized, stronger tectonic disruption of lithospheric ice. Eventually, we show that the smallest blocks identified are located from tens of m to 20–25 km from the Sulci fissures, while the largest blocks are found closer to the tiger stripes. This result supports the ejection hypothesis mechanism as the possible source of blocks.

Population Structure of Dungeness Crab (Cancer magister) in British Columbia

2008 ◽  
Vol 27 (4) ◽  
pp. 901-906 ◽  
Author(s):  
Terry D. Beacham ◽  
Janine Supernault ◽  
Kristina M. Miller
Keyword(s):  
British Columbia ◽  
Population Structure ◽  
Dungeness Crab ◽  
Cancer Magister

scholarly journals Effect of losing a fight on later agonistic behavior toward unfamiliar conspecifics in male Syrian hamsters

2011 ◽  
Vol 57 (4) ◽  
pp. 449-452 ◽  
Author(s):  
Javier Delbarco-Trillo ◽  
Robert E. Johnston
Keyword(s):  
Social Relationships ◽  
Syrian Hamster ◽  
Agonistic Behavior ◽  
Agonistic Interactions ◽  
Syrian Hamsters ◽  
The Third ◽  
Clear Winner ◽  
Male Subjects ◽  
Over Time

Abstract In many species, agonistic interactions result in social relationships that are stable over time. In Syrian hamsters, two unfamiliar males that are placed together will fight vigorously and a clear winner/loser relationship is usually established. In subsequent interactions, the loser will flee soon after detecting the familiar winner. Here we tested the hypothesis that losing a fight with a conspecific will affect future agonistic interactions not only toward that individual (i.e., the familiar winner) but also toward unfamiliar conspecifics. To test this hypothesis we paired two Syrian hamster males in three trials on one day in which the loser had the opportunity to escape the winner. The next day the loser was paired with an unfamiliar male, also for three trials. If he lost again, he was tested on a third day with a third unfamiliar male. Subjects were those males that were losers on all three days. The latency to escape on the first trial on Days 2 and 3 was significantly shorter than on the first trial on Day 1, indicating that losing against the first male affected the response toward unfamiliar males. However, the latency to escape on the first trial on Days 2 and 3 was significantly longer than that on the third trial on the preceding day, indicating that a loser treats unfamiliar males differently than a familiar winner. These results suggest that a defeat during an interaction with one male affects later agonistic behavior towards other, unfamiliar males.

scholarly journals A New Tool to Account for Crater Obliteration Effects in Crater Size-Frequency Distribution Measurements

2018 ◽  
Vol 5 (6) ◽  
pp. 258-267 ◽  
Author(s):  
Christian Riedel ◽  
Gregory Michael ◽  
Thomas Kneissl ◽  
Csilla Orgel ◽  
Harald Hiesinger ◽  
...  
Keyword(s):  
Frequency Distribution ◽  
Size Frequency Distribution ◽  
Crater Size ◽  
Size Frequency
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