Physiological effects in juvenile three‐spined sticklebacks feeding on toxic cyanobacterium Nodularia spumigena‐exposed zooplankton

Abstract

Feeding rate, growth and nutritional condition as well as nodularin concentration of juvenile three-spined sticklebacks Gasterosteus aculeatus were assessed in an experimental study where field-collected fish were given a diet of zooplankton fed with toxic Nodularia spumigena for 15 days. Food consumption was higher in N. spumigena bloom conditions compared with the cyanobacterium-free control, but despite this the growth rate of exposed fish did not improve. Control fish and fish fed N. spumigena-exposed zooplankton had higher RNA:DNA ratios and protein content than fish grown in cyanobacterial bloom conditions indicating good nutritional condition and recent growth of fish, whereas in bloom conditions metabolic transformation of nodularin to less toxic compounds may cause an energetic cost to the fish affecting the growth rate of the whole organism. Juvenile three-spined sticklebacks collected from the field contained higher concentrations of nodularin at the beginning of the experiment (mean 503Á1 mg kg À1 ). After 15 days, the lowest nodularin concentrations in fish were measured in the control treatment, suggesting that fish fed with non-toxic food are able to detoxify nodularin from their tissues more effectively than fish in continuing exposure.

Deposit-feeders accumulate the cyanobacterial toxin nodularin

“…In contrast, M. affinis increased its biomass several-fold when fed diatoms in similar experiments (Byré n et al, 2002(Byré n et al, , 2006. It is possible that coping with nodularin and other bioactive compounds may involve a metabolic cost for the animal, which could lead to reduce growth (Kozlowsky-Suzuki et al, 2003;Pä ä kkö nen et al, 2008). Lack of growth may also have been due to the low content in cyanobacteria of certain nutrients that are important for invertebrate growth (DeMott and Mü ller-Navarra, 1997), for example sterols and polyunsaturated fatty acids (Ahlgren et al, 1992).…”

“…Since cyanobacterial toxins, including nodularin, are considered more harmful to vertebrates than to invertebrates (Karjalainen et al, 2005), feeding on nodularincontaining invertebrates could pose a health risk for fish. Pike larvae and sticklebacks fed zooplankton exposed to N. spumigena showed decreased predation rate and growth (Karjalainen et al, 2005;Pä ä kkö nen et al, 2008). M. affinis is an important food source for a number of fish species, including the commercially important herring (Aneer, 1975) and M. balthica is a preferred prey of flounder (Karlson et al, 2007).…”

Toxin-producing cyanobacterium Nodularia spumigena, potential competitors and grazers: testing mechanisms of reciprocal interactions

“…Suikkanen et al (2006) proposed that the allelopathic effects of N. spumigena are most probably due to metabolite(s) other than nodularin. Also, nodularin has been implicated as the cause of harmful effects of N. spumigena on various crustaceans (Koski et al 1999, Kozlowsky-Suzuki et al 2003) and small fish (Kankaanpää et al 2001, Pääkkönen et al 2008). On the other hand, some animals ingest this cyanobacterium with no apparent harm (cladocerans: Sellner et al 1994, mysids: Engström et al 2001, ostracods and oligochaetes: Nascimento et al 2009, copepods: Gorokhova & Engström-Öst 2009 and may actually benefit from its presence (Schmidt & Jónasdóttir 1997, Engström et al 2001.…”

Consumption of benthic cyanobacterial mats and nodularin-R accumulation in freshwater crayfish (Paranephrops planifrons) in Lake Tikitapu (Rotorua, New Zealand)

“…The effect of the nodularin-R on aquatic organisms is varied, with fish generally showing the greatest sensitivity. Nodularin-R can cause severe liver damage in flounder and sea trout Vuorinen et al, 2009), oxidative stress in flounder (Persson et al, 2009) and reduces the growth of sticklebacks (Pä ä kkö nen et al, 2008). Invertebrates seem less sensitive to nodularin-R, however, crude extracts from Nodularia containing other bioactive compounds can have lethal and sub-lethal effects on some species and cause decreased egg production in copepods (Karjalainen et al, 2007).…”