Acute temperature quotient responses of fishes reflect their divergent thermal habitats in the Banda Sea, Sulawesi, Indonesia

Abstract

We measured metabolic rates of six Indo-Pacific fishes from different thermal habitats at 26°C and after acute transfer to 32°C. Temperature–metabolism relationships were expressed as temperature quotients (Q10) and ranged from ~1.0 in tidepool-dwelling common (Bathygobius fuscus) and sandflat (Bathygobius sp.) gobies to 2.65 and 2.29 in reef-associated white-tailed humbug (Dascyllus aruanus) and nine-banded cardinalfish (Apogon novemfasciatus), respectively. Squaretail mullet (Liza vaigiensis) and blackspot sergeant (Abudefduf sordidus) displayed Q10 responses of 2.03 and 1.26, respectively. Bathygobiids and blackspot sergeant inhabit mangrove tidepools during daytime low tides and experience temperature fluctuations approximately twice (12°C) the maximum experienced by inhabitants of patch reef or seagrass and squaretail mullet (1–6°C), a mangrove transient that avoids shallow, insolated daytime low tides. The low Q10 responses of the bathygobiids and blackspot sergeant suggest that their metabolic rates are relatively temperature-insensitive over the thermal range tested. Our data support the hypothesis that fish metabolic responses are tailored to specific thermal habitat conditions.