Species-specific impacts of suspended sediments on gill structure and function in coral reef fishes

Abstract

Reduced water quality, in particular increases in suspended sediments, has been linked to declines in fish abundance on coral reefs. Changes in gill structure induced by suspended sediments have been hypothesized to impair gill function and may provide a mechanistic basis for the observed declines; yet, evidence for this is lacking. We exposed juveniles of three reef fish species (, and) to suspended sediments (0-180 mg l) for 7 days and examined changes in gill structure and metabolic performance (i.e. oxygen consumption). Exposure to suspended sediments led to shorter gill lamellae in and and reduced oxygen diffusion distances in all three species. While exhibited impaired oxygen uptake after suspended sediment exposure, i.e. decreased maximum and increased resting oxygen consumption rates resulting in decreased aerobic scope, the oxygen consumption rates of the other two species remained unaffected. These findings imply that species sensitive to changes in gill structure such as may decline in abundance as reefs become more turbid, whereas species that are able to maintain metabolic performance despite suspended sediment exposure, such as or, may be able to persist or gain a competitive advantage.

Enhanced fast-start performance and anti-predator behaviour in a coral reef fish in response to suspended sediment exposure

“…Contrary to expectations, neither 7-day nor acute exposure to suspended sediments had negative effects on the fast start performance of fish. Exposure to suspended sediments for 7 days was found to compromise the aerobic performance of juvenile A. melanopus (Hess et al 2017), yet the locomotor performance of fish in the present study was enhanced rather than constrained. Similarly, acute exposure to suspended sediments did not influence the ability of fish to detect a stimulus that was a short distance away (∼5cm), simulating an ambush attack.…”

“…Prolonged exposure to elevated suspended sediments, however, has been shown to reduce the aerobic scope (i.e., the capacity for aerobic activities) of some reef fishes (Hess et al 2017); this may compromise their capacity to engage in or recover from energetically costly activities such as fast starts (Killen et al 2015). Yet, the effects of suspended sediments on the fast start performance of reef fishes are unknown.…”

What Is Gill Health and What Is Its Role in Marine Finfish Aquaculture in the Face of a Changing Climate?

“…The majority of studies, however, have focused on describing morphological changes observed in response to pollution (including toxins, heavy metals, and suspended particulate matter), parasites, and pathogens (e.g., Mueller et al, 1991;Ahmed et al, 2013;Zarha and Mobarak, 2015;Marcon et al, 2016), and little is known about whether gill remodeling may also occur in response to rising temperatures in these species. It is important to note, however, that modest changes in gill surface area or gas diffusion distances may not directly translate into changes in oxygen uptake and carbon dioxide excretion rates or other gill functions as these processes are influenced by numerous other factors as well (Robertson et al, 2015;Gilmour and Perry, 2018, see also Cumming and Herbert, 2016;Esbaugh et al, 2016;Hess et al, 2017). Findings in coral reef fish indicate that fish living at low latitudes and high average summer temperatures may generally have little capacity for gill remodeling in response to rising temperatures as many species already exhibit small gas diffusion distances, leaving little room for further decreases (Bowden et al, 2014).…”

The history, goals, and application of conservation physiology

“…variation in weather, climate) environmental variation influences organismal functioning . Examples of emerging success stories range from the finer-scale examination of how humaninduced increases in turbidity from sediment dredging in the Great Barrier Reef impact respiratory physi ology and gill microbiome responses in larval reef fish (Hess et al 2015(Hess et al , 2017Illing and Rummer 2017), to using energetic physiology and stable isotopes in wide-ranging oceanic top predators such as seabirds, tuna, and sharks to monitor how global change is impacting resource acquisition and key biological processes (Hennin et al 2016;Ferguson et al 2017;Pethybridge et al 2018;Descamps et al 2019;Lorrain et al 2020;Madigan et al, Chapter 5, this volume). Bringing this field together is the unified framework of 'macro-physiology'-the investigation of variation in physiological traits over large geographic and temporal scales and the ecological implications of this variation (Chown and Gaston 2016)-which is enabling researchers to predict and test a diversity of environment-physi ology relationships (Lennox et al 2018).…”