Ontogenetic shifts in fishes between vegetated and unvegetated tidepools: assessing the effect of physical structure on fish habitat selection

Abstract

The aim of this study of tidepool fishes was analyse variation in their use of intertidal habitats (rocky shore, mangrove and salt marsh). Specimens were collected during wet and dry periods from 18 tidepools in the three habitats. A total of 7690 specimens, belonging to 19 families and 30 species, was captured. The fish assemblage in rocky shore pools was clearly distinct from that of vegetated habitats (mangrove and salt marshes). The rocky shore fauna was dominated by permanent resident species, whereas pools in mangrove and salt marsh habitats were inhabited primarily by opportunistic and transient species. Habitat segregation by ontogenetic stage (e.g. smaller individuals in mangroves, intermediate size classes in salt marsh and sub-adults/adults on rocky shores) indicates age-related migration in response to the physical structure of these habitats and to the natural history of each fish species. These findings are important for the development of effective conservation and management plans for intertidal fishes.

Intertidal Biogeographic Subprovinces: Local and Regional Factors Shaping Fish Assemblages

“…Density was calculated by the number of individuals per pool volume (m 3 ). The fish taxa were assigned to one of three major feeding categories: Carn = carnivore; Omni = omnivore; Herb = herbivore, and the degree of residency was classified according to Macieira and Joyeux (2011), Oliveira et al (2016), complemented by personal observations from the authors.…”

“…In northern Brazil, the influence of the Amazon and other estuaries on coastal ecosystems is fundamental to the distribution and organization of marine species (Barletta et al, 2003;Rocha, 2003;Giarrizzo et al, 2010). For example, many of the intertidal ecotones of these two subprovinces are located within estuaries (Giarrizzo and Krumme, 2008;Oliveira et al, 2016), which not only determines the presence of a specific intertidal fish community, but also provides habitats for relatively large populations in comparison with the subprovinces located at higher latitudes (see Supplementary Table S3). Crabtree and Dean (1982) also found that estuarine tidepools harbor high fish densities.…”

Trophic relationships in tidepool fish assemblages of the tropical Southwestern Atlantic

“…The inter-tidal zone displays an enormous abundance and diversity of organisms despite being the marine ecosystem with the largest and fastest variation in environmental conditions (Little & Kitching, 1996). Its ecological importance is relevant considering the role it plays as feeding, breeding and nursery grounds for many organisms, especially for fishes and crustaceans (Gibson & Yoshiyama, 1999;Horn, Martin, & Chotkowski, 1999;Oliveira et al, 2016). Tropical ecosystems exhibit a wide range of inter-tidal habitats, including both unconsolidated substrates such as mudflats and sandy beaches (Andrades et al, 2014;Oliveira et al, 2016) and hard bottoms as such rocky shores and reef flats (Machado et al, 2015;Macieira & Joyeux, 2011;Macieira et al, 2015).…”

“…height and isolation), morphology (e.g. volume, surface area, depth and rugosity), substrate composition and physicochemical conditions (Macieira & Joyeux, 2011;Oliveira et al, 2016). However, factors influencing the organization and structure of tidepool communities remain understudied (Machado et al, 2015;Norton & Cook, 1999) and considerably less understood than those of communities exposed to the atmosphere at low tide (Zander et al, 1999).…”

“…However, despite the country's extensive coastline and high environmental heterogeneity, studies on tidepool fish communities are relatively scarce (e.g. Almeida, 1973;Almeida, 1983;Barreiros, Bertoncini, Machado, Hostim-Silva, & Santos, 2004;Cunha, Monteiro-Neto, & Nottinghan, 2007;Macieira & Joyeux, 2011;Machado et al, 2015;Macieira et al, 2015;Oliveira et al, 2016;Rosa et al, 1997), with a single unpublished work focusing on trophic ecology (Zamprogno, 1989). The identification of trophic guilds is fundamental to understanding the dynamics of fish assemblages, the functional role of species in the ecosystem and the factors responsible for organization and structure of communities (Castellanos-Galindo & Giraldo, 2008;Muñoz & Ojeda, 1997).…”