Nursery Habitat Shifts in an Estuarine Ecosystem: Patterns of Use by Sympatric Catfish Species

Abstract

The seasonal and spatial distribution (density and biomass) of five size classes of two catfish species (Cathorops spixii and Cathorops agassizii) were studied along an estuarine ecocline to test the relative importance of the nursery function of each habitat. Seasonal vs. area interactions were significant for all size classes of both species. During the early rainy season, the middle estuary is an important nursery habitat for juveniles of both species. When environmental conditions change during the late rainy season, the C. spixii primary nursery habitat shifts to the lower estuary. During this period, juveniles of C. agassizii remain in the middle estuary. Another important ecological area is the upper estuary, which becomes a breeding, spawning and hatchery area during the late dry season for both species. The nursery function of habitats shifts according to the seasonal fluctuation of salinity and dissolved oxygen, and each species responds differently to this change.

Ingestion of nylon threads by Gerreidae while using a tropical estuary as foraging grounds

“…Tropical estuaries and their mangrove forests allow marine organisms to complete their life cycle by providing protection and feeding grounds (Krumme et al 2005, Dantas et al 2012b. The presence of plastic debris in these areas is a threat to animals such as marine turtles (Guebert-Bartholo et al 2011) and fish (Possatto et al 2011, Dantas et al 2012a, which risk ingestion of plastics or entanglement.…”

<b>Habitat use by <i>Atherinella brasiliensis</i> (Quoy & Gaimard, 1825) in intertidal zones of a subtropical estuary, Brazil

“…A. brasiliensis does not have such well-developed structure (CARVALHO; CORRÊA, 2014), which indicates that this species perform short migrations, consequently, we suppose little migration between sectors in this study. The combination of reduced potential for migration (displacement) with adhesive benthic eggs and direct larval development (DEL RIO et al, 2005) seem to indicate that differences in the distribution patterns are mainly determined by local driving forces, with less influence of exchange of individuals between sectors. Shifts in habitat use by age classes of A. brasiliensis exhibited a marked pattern with younger individuals (< 1,1,2,3 months) being abundant in sectors 1 and 2, especially the sector 2, and individuals with more than 7 months of age distributed throughout the sampled area, mainly in the inner sectors 1 and 2.…”

“…Due to multiple spawning of the species, the reproductive aggregate demonstrated by the abundance of adults in the late dry period would have led to the finding of younger individuals of different ages during the rainy period. In laboratory, Del Rio et al (2005) described the embryonic development of A. brasiliensis, and registered that spawning and hatching take 6 days, the larvae hatch out with average total length of 5.04 mm (± 1.22 mm), reaching 13 mm total length after 40 days. When interpreting the results of temporal distribution, it is important to note the possible influence of the sampler, given the high probability of escape of individuals smaller than 15 mm through the net mesh and of larger individuals because of the low trawling speed.…”

“…The Brazilian estuarine fish fauna has been described in several works CONTENTE et al, 2011;VILAR et al, 2011;PASSOS et al, 2012), but few of them have addressed the shift of habitat during the ontogenetic development of fish (BECK et al, 2003;DANTAS et al, 2010DANTAS et al, , 2012MOURA et al, 2011).…”

“…Biological Sciences Maringá, v. 37, n. 2, p. 177-184, Apr.-June, 2015 IGNÁCIO;SPACH 2009;CONTENTE et al, 2011), which has adhesive benthic eggs and direct larval development (DEL RIO et al, 2005). The length at first maturity of females ranges from 7.6 and 9.1 cm in the studied environments, with recruitment during October and January with multiple spawning (BERVIAN; FONTOURA, 1997;FÁVARO et al, 2003).…”