Exposure to moderately elevated temperatures changes food preferences in the tropical marine herbivore Haliotis squamata

Abstract

Ocean warming is affecting marine ectothermic herbivores as well as the macroalgal species they consume and this has the potential to alter their trophic interaction. However, it is currently still unknown how these two important components of benthic food webs will react to a warming environment. Consumption rates of grazers change with increasing temperatures, but it is unclear whether this is also true for feeding preferences. In this study, multiple-choice feeding assays with the tropical abalone Haliotis squamata from Western Indonesia were conducted in August 2018. After brief acclimation of either the grazer or the macroalgae to moderately elevated water temperatures (maximum 2 °C above the long-term average) in the laboratory, three species of living macroalgae were simultaneously offered to the abalone in feeding assays. Consumption rates of H. squamata were lower under elevated water temperatures, while its feeding preference switched: At 27 °C (2 °C below long-term average), abalone preferred non-acclimated Gracilaria salicornia, but switched to non-acclimated Amphiroa spp. at 31 °C. Interestingly, no such switch in preference occurred when the macroalgae, but not the grazers were acclimated. This indicates that the grazer will presumably be the driver of this potential change in interactions between H. squamata and its macroalgal food. Ocean warming may result in changes in the structure of benthic communities, mediated by changes in the feeding behaviour of herbivorous invertebrates.

The role of grazers in early-life stages of Cystoseira sensu lato can be crucial in the restoration of marine forests

“…Chemical defences, such as phlorotannins, present in Fucoids could be as well affected by climate change, as is the case of F. vesiculosus, making macroalgae more susceptible to grazing (Raddatz et al, 2017;Kinnby et al, 2021). The palatability of macroalgal species can change under ocean warming, elevated pCO 2 , increased salinity, and nutrient conditions, enhancing grazing and constituting an additional threat under future climate change scenarios (Asnaghi et al, 2013;Gutow et al, 2014;Kinnby et al, 2021;Mitterwallner et al, 2021;Illa-Loṕez et al, 2023).…”

An Overview of the Indonesian Abalone Industry: Production, Market, Challenges, and Opportunities

“…Abalone species like H. asinina and H. squamata need specific nutrients to grow and survive. These abalone eat seaweed and other macroalgae, according to several studies [35], [36]. Abalone grow best on a diet of various seaweed species, according to the study.…”

Population genetic and genomic approaches for the management of the blackfoot paua, Haliotis iris Gmelin 1791, within the genus context

“…All species of haliotids present conserved (primitive) morphological traits also described for the fossils of the genus. The following description of the anatomy of abalone (Cox, 1962;Geiger & Owen, 2012) can be assumed for every species known nowadays with specific differences in maximum body size and colour of the nacre and the outer part of the shells attributed to adaptation to different temperature regimes (body size, reviewed by Lindberg, 1992;Estes et al, 2005;Searle et al, 2006) and feeding preferences determined by resources availability (Mitterwallner et al, 2021). All haliotids are characterised by an auriform shell with an inner nacreous layer of aragonite and an outer layer made of calcite.…”