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Movement patterns of river crabs (Decapoda, Potamoidea) in the field: predictable and unpredicatable components
Author(s) -
Barbaresi S.,
Gherardi F.,
Vannini M.
Publication year - 1997
Publication title -
journal of zoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.915
H-Index - 96
eISSN - 1469-7998
pISSN - 0952-8369
DOI - 10.1111/j.1469-7998.1997.tb05800.x
Subject(s) - biology , decapoda , freshwater crab , crustacean , population , fishery , ecology , zoology , demography , sociology
Radio‐telemetry was used to investigate locomotor activity rhythms in a field population of the freshwater crab Potamon fluviatile . Fourteen adult specimens were radio‐tracked almost continuously over a 13‐day period along a hill stream in Tuscany, Italy. A rough nychthemeral movement pattern was found in some animals of both sexes. None of the crabs showed a constant activity on different days, nor did they follow any periodical pattern. Although average displacement amounted to about 5m/d, activity was concentrated over several days at a time, followed randomly by periods of almost total inactivity. On average, only about 3/4 of radio‐tagged crabs were active every day and only a small fraction active at the same time. The crabs spent about 60% (females) or 70% (males) of their time out of the water, but there was no regular pattern in land‐water preference. The random high variation in locomotor activity on different days seems to be a constant pattern in all decapods that have been studied so far, using individual marking techniques.