Spatial and vertical patterns in the tidepool fish assemblage on the island of O`ahu

Abstract

The microtides, wave regimes, and relative isolation of the Hawaiian archipelago may provide unique environmental and biogeographic effects that shape the structure of tidepool fishes. We sampled fishes across a narrow gradient at low tide from 6 sites on the island of O`ahu. We tested predictions of the hypotheses that environmental conditions (pool depth, volume, macroalgal cover, temperature, and salinity) would result in a vertically structured tidepool fish assemblage unique to basalt or limestone rocky shores. 343 fish were recorded from 40 pools, and 19 species from 10 families were identified. Tidepool fish diversity (H': O`ahu=2.4; Sites Average=0.0-0.9) was typical for tropical islands, with members from Gobiidae (5 species), Blenniidae (4 species), Pomacentridae (3 species), Acanthuridae (2 species) and Kuhliidae (2 species) among the most common. Endemism (32%) was higher than other well studied assemblages yet similar to Hawaiian reef fishes (25%). Assemblage abundance varied among shores with basalt or limestone substrate, among sites, and vertically among high, mid, and low pools. In general, blenniids occurred at higher proportions on limestone shores and gobiids were more common on basalt shores. High pools were characterized by an abundance of a small sized (29.0 mm median standard length) blenniid Istiblennius zebra, while the blenniid Entomacrodus marmoratus and wrasses Thalassoma spp. were more common in low pools. Temperature was the best environmental predictor of assemblages and this relationship warrants further investigation. Our findings indicate that assemblages can vary across a narrow geographical range and intertidal shore.

Spatial and Temporal Variation in Rocky Intertidal Communities Along the Main Hawaiian Islands

“…Hard substratum type could be an indicator of habitat availability because rock types may erode or form similarly, providing different types of habitats suitable for different types of organisms. Furthermore, intertidal fish assemblages are known to vary with substratum type ( Yoshiyama et al 1986, MacPherson 1994, Cox et al 2010. However, for benthic organisms abundance and composition did not vary with substratum type.…”

Ichthyofaunal diversity and vertical distribution patterns in the rockpools of the southwestern coast of Yaku-shima Island, southern Japan

“…Fish identification and standard lengths (SL) were according to Nakabo (2013), and the taxonomic-revised groups were described as follows: Murase (2013) considered species of Scorpaenodes as "Scorpaenodes spp." because of a taxonomic problem between S. guamensis and S. scaber following a personal communication from Dr. H. Motomura (Kagoshima University Museum), however, thereafter Motormura (2014) stated that S. scaber was an endemic species of Murase et al 2010;Cox et al 2011). But, Murase (2013) did not consider the spatial distribution pattern of the rockpool fish assemblage in relation to the vertical levels of each rockpool sampled.…”

Influence of rock‐pool characteristics on the distribution and abundance of inter‐tidal fishes

“…The distribution of species across continents and with latitude can be explained by dispersal ability and geographic patchiness, while community patterns at regional and local scales are largely driven by the physical and chemical factors of the environment (Gibson & Yoshiyama ; Cox et al . ).…”

“…Very few, however, have tried to determine how all of these features interact with one another to regulate overall assemblage structure and species composition (Cox et al . ; Macieira & Joyeux ).…”