The amphipod Corophium multisetosum (Corophiidae) in Ria de Aveiro (NW Portugal). II. Abundance, biomass and production

Abstract

The abundance and biomass of Corophium multisetosum Stock, 1952 were determined from benthic corer samples collected monthly over 1 yr in the upper reaches of Canal de Mira (Ria de Aveiro, Portugal). Both density and biomass over the sampling period were negatively correlated with water temperature and positively correlated with chlorophyll a concentration in the sediment. C. multisetosum density was signi®cantly negatively correlated with plant biomass and positively correlated with salinity. The nature of the sediment, favourable environmental conditions, high availability of food and low interspeci®c competition allowed the population to reach a maximal density of 200´10 3 individuals m )2 and a maximal biomass (ash-free dry wt, AFDW) of 62 g AFDW m )2 . The population was highly productive, especially during the autumn/winter period. Production, estimated by two dierent methods (Hynes method: 251 g AFDW m )2 yr )1

The amphipod Corophium multisetosum (Corophiidae) in Ria de Aveiro (NW Portugal). I. Life history and aspects of reproductive biology

“…In the population of C. triaenonyx at Visakhapatnam (18°N), breeding does not take place in summer, and peaks during the autumn (Shyamasundari 1972), as with C. multisetosum at AreaÄ o. The good physiological condition of C. multisetosum in autumn (Cunha et al 2000b) certainly favoured the reproductive activities during this period.…”

“…The ®eld data are interpreted together with some information from laboratory experiments (Re 1996), and are discussed in relation to other studies on several Corophium species. Production estimates and certain aspects of the population dynamics (density and biomass) in relation to environmental factors are considered in the following paper in this issue (Cunha et al 2000b).…”

Mass balanced models of the food web in three areas along a gradient of eutrophication symptoms in the south arm of the Mondego estuary (Portugal)

“…Diet information for almost all the compartments here identified had to be obtained from the literature (e.g. Hughes, 1969;Costa, 1982;Pihl, 1985;Zajac, 1986;Sprung, 1994;Ansell et al, 1999;Azeiteiro et al, 1999;Cunha et al, 2000;Pardal et al, 2000, see Appendix A). Initially, all prey items of each compartment of macrofauna and fishes were listed, along with their corresponding percentages of occurrence.…”

Life history, aspects of reproductive biology and production of Corophium orientale (Crustacea: Amphipoda) in Monolimni lagoon (Evros Delta, North Aegean Sea)

“…Nevertheless, the life history, reproductive biology, population dynamics or production have been studied only in a few Corophium species (e.g., Onbe´, 1966;Casabianca, 1967Casabianca, , 1972Casabianca, /73, 1975Muus, 1967;Labourg, 1968;Birklund, 1977;Sheader, 1978;Fish & Mills, 1979;Nair & Anger, 1979;Cunha et al, 2000b, c;etc).…”