Impact of clay particles on the cutaneous exchange of oxygen across the chorion of Atlantic salmon eggs

Abstract

Rates of oxygen consumption for Atlantic salmon Salmo salar embryos approaching hatching were determined. Values were recorded using a 'closed system' experimental set-up. A magnetic stirrer was used to ensure that zones of oxygen depletion did not develop in the microenvironment surrounding the respiring eggs. Recorded values of oxygen consumption ranged from 0Á0024 to 0Á0038 mg O 2 egg À1 h À1 , with a mean consumption rate of 0Á0032 mg O 2 egg À1 h À1 . The values of oxygen consumption were similar to those reported in other studies using a closed system experimental set-up, however, they were lower than those reported in a study adopting a flow-through system. The introduction of clay-sized sediment to the incubation chamber created a thin film (<1 mm) of sediment on the egg surface, and resulted in reduced rates of oxygen consumption. The additional 0Á3 g of clay sediment reduced oxygen consumption by an average of 41% and the addition of a further 0Á2 g of clay sediment reduced consumption by an average of 98%. Two explanations for the recorded reduction in consumption were proposed: (i) the creation of a low permeability seal around the eggs restricted the availability of oxygen to the incubating embryos and (ii) the clay-sized fine sediment physically blocked the micro-pore canals in the egg membrane, thereby restricting oxygen uptake. # 2005 The Fisheries Society of the British Isles

Interactions between fine-grained sediment delivery, river bed deposition and salmonid spawning success

“…However, many ways in which fine sediment impacts upon fish egg survival, are not represented in SIDO-UK; e.g. the surface sealing caused by sand (Beschta and Jackson, 1979), the impacts of clay biofilms around eggs (Greig et al, 2005) and sediment-associated contaminants. The findings from this study, and the further application of SIDO-UK, may have significant implications for informing the management of sediment delivery to salmonid rivers (Collins and McGonigle, 2008;Collins et al, 2012).…”

“…Several studies (Chapman, 1988;Sear et al, 2008) have found that sediment infiltration into the redd reduces the spawning success rate. There have been several hypotheses put forward to explain this observation: (a) physical blockage of intragravel pores, where the reduction in gravel porosity and permeability results in the reduction in intragravel flow velocities and therefore a decrease in the supply of oxygen rich water to the egg zone; (b) sediment oxygen consumption, where the organic matter associated with the finer size classes decomposes using oxygen, meaning it becomes limiting for egg survival, and; (c) egg membrane micropores are blocked (Greig et al, 2005) limiting metabolic exchanges. The success of salmonid spawning is therefore a function of the coincidence of fine sediment delivery and the development of the salmonid eggs during the incubation period.…”

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“…Colmation describes the process leading to clogging of river beds with fine sediments due to gravitational settling, advection and further infiltration deep into the bed matrix (Boano et al, 2014;Lawler et al, 2009). This limits oxygen supply to salmonid eggs and restricts the hyporheic flow that is crucial for processing contaminants and flushing out waste products (Greig et al, 2005(Greig et al, , 2007Sear et al, 2014). It also limits the emergence of recently hatched fry by creating a seal (Sear et al, 2008).…”

“…Coarser fractions of the suspended sediment load are more likely to be deposited, increasing the erodibility of macrophyte beds ( Jones et al, 2012a) and clogging redds (Greig et al, 2005), whereas finer particles (< 2 µm) are more likely to affect the respiratory organs and feeding apparatus of fish and invertebrates (Bilotta and Brazier, 2008). Clay-sized (<4 µm) particles can be trapped by periphyton, reducing its attractiveness to grazing organisms (Graham, 1990).…”

Survie Embryonnaire Du Saumon Atlantique (Salmo Salar L.) Dans Un Cours D’eau Du Sud De Son Aire De Répartition, La Nivelle

“…Le taux d'incorporation des fractions < 1 mm est faible (augmentation de 12 % par rapport à leurs valeurs initiales), et la proportion d'éléments > 5 mm demeure sensiblement la même. Toutefois, des proportions de sables et de fines < 2mm telles que celles observées (18 % ou plus) sont suffisantes pour réduire la disponibilité d'oxygène pour les oeufs (GREIG et al, 2005) et induire des mortalités conséquentes. Ainsi, des proportions de 15 à 20 % de ces éléments entraînent de fortes baisses de survie chez diverses espèces de salmonidés dans les frayères (MCNEIL, 1964 ;TAGART, 1976 ;HAUSLE et COBLE, 1976) ou en milieu contrôlé (PETERSON et METCALFE, 1981 ;LAPOINTE et al, 2004).…”