Interim report of the HELCOM CORESET project

3.13 B. Reproductive disorders in fi sh and amphipods:
Reproductive success in amphipods
Authors: Brita Sundelin, Doris Schiedek and Kari Lehtonen
ICES SGEH Biological Effects methods Background Documents
for the Baltic Sea region (ICES/OSPAR document from the ICES
SGIMC Report 2010, complemented and modifi ed by SGEH
2011 with information relevant for application in the Baltic Sea
region)
Description of the indicator
Crustacean amphipods are regularly used in bioassays and laboratory exposure experiments for effects of
contaminants. They carry their brood in an egg chamber until hatching and by analyzing the reproduction
success we can score the effects of contaminant load in sediment and water. Twenty years of ecotoxicological
studies in soft-bottom microcosms and studies of fi eld populations collected in contaminated
industrial areas have demonstrated toxicant-sensitive variables on the embryonic development of the Baltic
amphipod species Monoporeia affi nis and Pontoporeia femorata (Sundelin 1983, 1984, 1988, 1989, 1998,
Eriksson et al. 1996, Eriksson et al. 2005) and other amphipod species (Ford et al. 2003a, Sundelin et al.
2008, Bach et al. 2010).
When exposed to heavy metals, chlorinated organic compounds, pulp mill effl uents or contaminated sediments
in bioassays as well as in fi eld studies, the frequency of malformed embryos has been demonstrated
to be signifi cantly higher when compared to control microcosms and reference areas (Elmgren et al. 1983,
Sundelin 1983, 1984, 1988, 1989, 1991, Eriksson et al. 1996, Sundelin & Eriksson 1998, Eriksson et al.
2005) suggesting the variable to be a general bioindicator of contaminant effects. Organic contaminants
are often associated to lipids. During oogenesis large quantities of lipids are deposited into the developing
oocytes (Herring 1974, Harrison 1990, Harrison 1997, Wouters et al. 2001, Rosa & Nunes 2003). These
lipids, which consist mostly of monounsaturated fatty acids, are utilized and consumed during embryo
development (Morais et al. 2002, Rosa et al. 2003, 2005), potentially leading to toxic effects of lipophilic
contaminants increasing during embryogenesis. These effects also arise in low concentrations that do not
demonstrably affect the sexual maturation, fertilization rate, fecundity (eggs/female) and rate of embryo
development (time to hatching), indicating embryogenesis to be even more sensitive than other variables of
the reproduction cycle.
All amphipod species show a similar direct embryo development despite differences in sexual behaviour
before mating and in duration of embryogenesis that differs, mainly due to ambient temperature (Bregazzi
1973, Lalitha et al. 1991, McCahon & Pascoe 1988). Therefore, this similar development allows for a consistent
method of staging embryogenesis amongst all amphipod species and any resultant aberrations,
which makes them particularly good for biomonitoring reproduction effects in situ. Other embryo aberrations
respond to oxygen defi ciency, scarcity of food quality and quantity and temperature stress (Eriksson
et al. 2001, 2004, Sundelin et al. 2008). Multiple stressors act in concert in the environment and by analysing
different types of aberrant embryo development we can discriminate between some of them. The
method gives information about health status of the amphipod populations since diseases, parasite infection,
sexual maturation in terms of oogenesis in females and sexual development in males and fecundity
are scored.
Confounding factors
Malformed embryos seem to be comparatively insensitive to other environmental stressors but contaminant
exposure. However a seven year fi eld study showed a correlation between organic content in the
sediment and malformation rate (Eriksson et al. 2004). This could likely depend on higher concentrations
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