Life history of the amphipod &lt;i&gt;Corophium insidiosum&lt;/i&gt; (Crustacea: Amphipoda) from Mar Piccolo (Ionian Sea, Italy)

Ermelinda Prato,Francesca Biandolino

doi:10.3989/scimar.2006.70n3355

Abstract

A one-year study was conducted on the life history of the amphipod Corophium insidiosum (Crawford, 1937) in the Mar Piccolo estuary (Southern Italy). Monthly collections were made to investigate certain aspects of population structure, abundance and reproductive biology. Population density showed a clear seasonal variation: with a maximum in spring-summer and a minimum in autumn-winter. Although brooding females were present all year round, recruitment occurred in spring, decreased in summer, peaked in autumn and almost ceased during the winter. 7-8 new cohorts in all samples could be recognised from April 2002 to November 2002. Mean longevity was ~5 to 6 months, and the estimated lifespan was longer for individuals born in late summer than for individuals born in spring. The sex ratio favoured females with a mean value of 1.51, but males grew faster and attained a larger maximum body length than females. Males and females became distinguishable at roughly > 2 mm, reaching a maximum size of 5.6 mm for females and 6.0 mm for males during the winter months. The females reproduced for the first time when they reached 2.2 mm body length. The number of eggs carried by females was related to the size of the female.

Highlights

Crawford described Corophium insidiosum in 1937 and separated this species from the closely related species C. bonnellii Milne–Edwards, 1830.Females of both species are very similar morphologically.C. insidiosum is a widespread and frequently recorded species along the European coast: in the Mediterranean Sea
SUMMARY: A one-year study was conducted on the life history of the amphipod Corophium insidiosum (Crawford, 1937) in the Mar Piccolo estuary (Southern Italy)
Mean longevity was ~5 to 6 months, and the estimated lifespan was longer for individuals born in late summer than for individuals born in spring

Summary

Introduction

Crawford described Corophium insidiosum in 1937 and separated this species from the closely related species C. bonnellii Milne–Edwards, 1830.Females of both species are very similar morphologically.C. insidiosum is a widespread and frequently recorded species along the European coast: in the Mediterranean Sea Crawford described Corophium insidiosum in 1937 and separated this species from the closely related species C. bonnellii Milne–Edwards, 1830. Females of both species are very similar morphologically. Casabianca, 1967, 1968; Krapp-Schickel, 1971; Anger, 1979; Myers, 1982), and in the North Sea and western Baltic Sea (Köhn, 1996). It is recorded in the Atlantic Ocean (European and North American coasts) and the Pacific Ocean (west coast of America, Chile, Japan), (Crawford, 1937; Bousfield and Hoover, 1997)

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Discussion

Conclusion