Diet of subtropical herbivorous fishes in northeastern New Zealand

Abstract

Diet was examined in four species of marine herbivorous fishes in northeastern New Zealand, which for three species represents the southern end of their range. Aplodactylus etheridgii (Aplodactylidae) and Girella cyanea (Girellidae) are restricted to the subtropical southwest Pacific region, whereas Kyphosus bigibbus (Kyphosidae) is distributed antitropically in the Indian and Pacific oceans. The temperate Australasian herbivore A. arctidens was also examined for comparative purposes. Aplodactylus etheridgii and A. arctidens predominantly consumed rhodophytes (91.22% ± 4.12 SE and 72.50% ± 6.63 SE, respectively), with A. arctidens also consuming a significant proportion of chlorophytes (22.65% ± 6.91 SE), mainly Viva spp. Kyphosus bigibbus consumed predominantly phaeophytes (91.50% ± 2.69 SE), mainly Carpophyllum spp., with the remainder consisting of rhodophytes. Girella cyanea was omnivorous, consuming some animal material (12.45% ± 7.29 SE), mainly sponges and hydroids.

Histology and ultrastructure of the gastrointestinal tract in four temperate marine herbivorous fishes

“…The concentration of SCFA and gut throughput time are similar between O. pullus and K. sydneyanus (Clements et al, 2014), giving the potential for digesta to remain in the hindgut for a longer period and allowing the fish to assimilate a greater proportion of available nutrients. These two species mainly consume phaeophytes, whereas the aplodactylids consume more readily digestible rhodophytes and some chlorophytes (Clements & Choat, 1993Clements & Zemke-White, 2008;Moran & Clements, 2002). Bacteria were observed in close proximity to algal fragments in histological preparations from sections III, IV and V of all study species.…”

Using qualitative data to classify reef fishes into dietary guilds

“…Owing to the broad, latitudinal range of the country, New Zealand's fish fauna includes sub-antarctic, temperate and subtropical species with a diverse range of feeding ecologies (Hillebrand 2004). To date, feeding modes of New Zealand fishes have been inferred through morphological measures and traits (Ladds et al 2018(Ladds et al , 2020Myers et al 2020) or limited to small-scale dietary studies of particular taxa or regions (Russell 1983;Denny & Schiel 2001;Clements & Zemke-White 2008). Due to a lack of comprehensive diet studies of New Zealand's reef fishes, the extent to which particular resources, such as algae and plankton, are exploited among species remains poorly understood, and any delineation of dietary functional groups remains subjective.…”

“…2018, 2020; Myers et al . 2020) or limited to small‐scale dietary studies of particular taxa or regions (Russell 1983; Denny & Schiel 2001; Clements & Zemke‐White 2008). Due to a lack of comprehensive diet studies of New Zealand’s reef fishes, the extent to which particular resources, such as algae and plankton, are exploited among species remains poorly understood, and any delineation of dietary functional groups remains subjective.…”

Using optimised otolith sectioning to determine the age, growth and age at sexual maturity of the herbivorous fish Kyphosus bigibbus: with a comparison to using scales

“…bigibbus is widely distributed in the subtropical and temperate regions of the Indian, Pacific and Atlantic oceans Clements 2013, 2016). This species is an obligate herbivore, with a diet consisting predominantly of brown algae (Clements and Choat 1997;Clements and Zemke-White 2008;Yatsuya et al 2015). In the Ningaloo Reef, Australia, K. bigibbus is one of the main consumers of macroalgae, with feeding rates being highest when individuals of this species form part of monospecific groups (Michael et al 2013).…”