Population Structure of the Freshwater CrabPotamon algeriense(Bott, 1967) Inhabiting Oued Zegzel, (Northeast of Morocco)

Soufiane Fadlaoui,Mohammed Melhaoui

doi:10.1155/2019/7281725

Abstract

This is the first study to determine the population structure of the freshwater crabPotamon algeriensein Oued Zegzel, a mountain stream in the northeast of Morocco. Monthly collections were carried out by hand, from October 2017 to September 2018. A total of 669 individuals, 378 males and 291 females, were captured, measured, marked, and released. Due to their extremely cryptic behavior during egg incubation, few ovigerous females were caught during the entire sampling period. The average size of males (28.98 ± 10.78 mm CW) is significantly larger than that of the females (28.62 ± 8.48 mm CW). Significant deviation from 1 : 1 sex ratio during the study period was recorded, and the size distribution of the sampled population presented an abnormal distribution where specimens over 31 and under 25 mm CW were often males, whereas females were represented more in the 26–30 mm CW range.

Highlights

Compared with marine crabs, freshwater crabs are considered to have rather low dispersal ability and high rates of endemism [1]. ey can cross longer terrestrial distances away from their aquatic habitat under humid conditions [2, 3]
We found the freshwater crab Potamon fluviatile, which its distribution covers, parts of many countries especially, in mainland Italy and on the Balkan Peninsula from Dalmatia to the Axios river in Greece [11]
Specimens over 31 and under 26 mm Carapace Widths (CW) were more often males, and this class coincides with the size at which the puberty ecdysis occurs [20], whereas females were represented mostly in the 26–30 mm CW range

Summary

Introduction

Freshwater crabs are considered to have rather low dispersal ability and high rates of endemism [1]. ey can cross longer terrestrial distances away from their aquatic habitat under humid conditions [2, 3]. Ey can cross longer terrestrial distances away from their aquatic habitat under humid conditions [2, 3]. Their philopatry is increased by the absence of marine planktonic larvae and by their brood care behavior. Is family includes many studied species, for example, the subspecies Potamon potamios palestinensis found in Palestine is widely represented in aquatic habitats throughout most of the country, comprising the arid Negev, and its distribution extends as far as the northernmost corner of Sinai [9]. This species behaves as a generalist, actively preying on frogs, fishes, and various invertebrates [10]

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Results

Conclusion