Shifts in Labridae geographical distribution along a unique and dynamic coastline

Abstract

Aim: Compare the distribution and composition of temperate Labridae (wrasse) assemblages on shallow water coastal reefs in South-Western Australia between 2006 and 2015, after a decade characterized by both gradual ocean warming and severe heatwave events. Location: South-Western Australia from Port Gregory to the Recherché Archipelago. Methods: Surveys of Labridae fishes were conducted in 2006 and repeated in 2015across 112 reefs spanning 2,000 km of coastline, using diver-operated stereo-video systems (stereo-DOVs). We used a hierarchical design with seven regions, four locations in each region, four reef sites in each location and twelve transects in each site. Results:In 2015, we found an increase in abundance of tropical and subtropical labrid species that were rarely observed in 2006. Three temperate species declined in abundance, which tended to be large and slow growing fish. Twenty-two labrid species increased in abundance. There was also a discernible poleward shift in 20 of the 25 most abundant and representative labrid species from 2006 to 2015. The labrid community composition was explained predominantly by sea surface temperature (SST), physical reef structure and kelp (Ecklonia radiata) cover. Main conclusions:Our study reveals that labrid assemblages associated with the shallow water temperate reefs of South-Western Australia have undergone rapid changes across almost 2,000 km of coastline, with warm-temperate waters showing the strongest change. However, cool-temperate waters on the south coast also showed significant changes in the composition of the labrid assemblages. Our findings provide important insights into the effects of warming and habitat loss on warmtemperate assemblages and the potential trajectory of change for cool-temperate assemblages under a warmer future. K E Y W O R D Sassemblage shifts, climate change, endemic fish, Labridae, marine, sea surface temperature, South-Western Australia

Range‐extending tropical herbivores increase diversity, intensity and extent of herbivory functions in temperate marine ecosystems

“…The composition of fish assemblages in coastal habitats of western Australia has changed following a marine heatwave that struck the region in 2011 (Wernberg et al., 2016). Tropical rabbitfish Siganus fuscescens have since formed self‐recruiting populations in temperate ecosystems (Lenanton, Dowling, Smith, Fairclough, & Jackson, 2017; Zarco‐Perello et al., 2019) while parrotfish Scarus ghobban and S. schlegeli became more abundant (Parker et al., 2019). To identify the effects of these changes, surveys of herbivorous fish were conducted over inshore habitats along the coastline of south‐western Australia during summer (April–May) of 2018 and 2019, from the Perth metropolitan area to Cape Naturaliste in the south of the state.…”

“…The composition of fish assemblages in coastal habitats of western Australia has changed following a marine heatwave that struck the region in 2011 (Wernberg et al, 2016). Tropical rabbitfish Siganus fuscescens have since formed self-recruiting populations in temperate ecosystems (Lenanton, Dowling, Smith, Fairclough, & Jackson, 2017;Zarco-Perello et al, 2019) while parrotfish Scarus ghobban and S. schlegeli became more abundant (Parker et al, 2019).…”

Occurrences of tropical, subtropical and rare marine fishes in Aotearoa New Zealand indicate biodiversity change

“…Labrids and pomacentrids are highly speciose filling a range of functional groups, covering a variety of dietary and habitat preferences (Parenti & Randall, 2018; Stuart‐Smith et al, 2021). Furthermore, they have high dispersal potential (Cure et al, 2018; Feary et al, 2013; Parker et al, 2019); labrids have relatively long pelagic larval durations (Victor, 1986), and several pomacentrid species are known to raft with marine debris, extending their pelagic dispersal (Luiz et al, 2015; Thiel & Haye, 2006). Although evidence suggests that many wrasse and damselfish species are cold‐tolerant and can over‐winter and persist in temperate environments (Booth et al, 2018), in NZ, occurrences of these families were limited to the Northland coast from Whangaroa south to the Hauraki Gulf (Figure 6).…”

Marine ecoregions and subecoregions within Indo‐West Australian waters: A statistical approach based on species distributions

“…Environmental drivers of distributions for a broad range of taxonomic groups in Indo-West Australian ecoregions are poorly understood, and studies on associations among species distribution and environmental variables are limited both geographically and taxonomically. For example, the distribution of subtidal Labridae fishes from Port Gregory to the Recherche Archipelago (Parker et al, 2019) and subtidal macrophyte assemblages along the Pilbara coast (Olsen et al, 2019) is strongly correlated with sea surface temperature. Similarly, subtidal sponge distribution along the Dampier Archipelago (Fromont et al, 2006), subtidal benthic assemblages between Abrolhos Island and Cape Naturaliste (Hovey et al, 2012;Smale et al, 2010), coastal fish assemblages along the Recherche Archipelago (Harvey et al, 2013), and deep-sea decapods along Western Australian continental margin (McCallum et al, 2013) exhibit significant relationships with depth.…”

“…Indo-West Australian waters consist of nine ecoregions: Western Sumatra, Southern Java, Lesser Sunda, Bonaparte Coast, Exmouth to Broome, Ningaloo, Shark Bay, Houtman, and Leeuwin, according to the MEOW system (Spalding et al, 2007). Many studies have examined the biogeographical distribution of marine species in these waters but were limited to certain marine taxa and conducted partially within ecoregions (Azzarello et al, 2014;Bessey et al, 2019;Fromont et al, 2006;Hadiyanto et al, 2020;Harvey et al, 2013;Johansson et al, 2010;Olsen et al, 2019;Sampey et al, 2014;Wernberg et al, 2003) or between ecoregions (McCallum et al, 2013;McEnnulty et al, 2011;Miller et al, 2011;Parker et al, 2019;Siringoringo et al, 2019;Smale et al, 2010;Walker & Prince, 1987;Waters et al, 2010;Woolley et al, 2013). Hence, studying the distribution of a broad range of taxonomic groups across a range of Indo-West Australian ecoregions is needed to test the suitability of the MEOW system to represent species distributions.…”