Login below, or create an account for free.
Coastal reefs are some of the most diverse ecosystems on
the planet, hosting over 3000 fish species that fulfil important ecological
roles (Bellwood et al. 2013). This diversity sustains important artisanal
fisheries as well as economically valuable ecotourism industries, ensures
ecosystem stability and can also accelerate coral reef recovery from
disturbances such as cyclones and bleaching (Bellwood et al. 2013).
However, the productivity, species composition and growth
rates of fish in coastal reefs is changing in response to habitat degradation
and climate change (Munday et al. 2008), yet we do not understand the role of
pelagic and benthic productivity in sustaining these ecosystems.
Recent studies in coastal upwelling systems in South America
have demonstrated that coastal reefs almost completely (up to 99%) depend on
pelagic productivity (Docmac et al. 2017). However, it is entirely unclear to
what extent this applies to other coastal ecosystems, including those in
Australia (Truong et al. 2017).
Are coral and rocky reefs or temperate kelp forest
ecosystems similarly dependent on pelagic production or do they act as largely
self-sustained systems? And how will the climate driven shifts in oceanic
circulation, changes in species distribution, rates of pelagic production and
coastal habitat degradation affect the relative importance of benthic (mostly
local) versus pelagic (mostly imported through water exchange) food sources and
The broad goals of this project are therefore to quantify
the role of pelagic and benthic carbon sources in sustaining coastal reef
productivity, and how/if the ratio of benthic:pelagic carbon sources changes
with latitude for overall reef biomass, and/or for particular species where
applicable. Further, in order to support conclusions drawn from isotopic
signatures, this project will examine the gut contents of all fish collected.
In addition to identifying gut contents to the finest taxonomic resolutions
feasible, gut contents will also be measured providing valuable data for
size-based models. The specific aims of this study are therefore as follows:
Investigate the isotopic signatures of fish and basal food sources, to
determine the ratio of pelagic/benthic carbon supporting the biomass of key
fish functional groups on shallow reefs. Examine the gut contents of fish to
provide size spectrum diet data for size-based ecosystem models; and, to
validate conclusions drawn from isotopic analyses. Determine the congruence of
methods for deriving fish trophic level, by comparing the overlap in
statistical clustering of fish species via gut content and stable isotope
methods, as per Cresson et al. (2014).
This is a study led by Amy Coghlan from the Institute for Marine and Antarctic Studies, University of Tasmania and supported by researchers from UNSW who have collaborated in fieldwork.