Spring-neap cycle as a major driver of temporal variations in feeding of intertidal fishes: Evidence from the sea catfish Sciades herzbergii (Ariidae) of equatorial west Atlantic mangrove creeks

Abstract

On macrotidal coasts, short-to medium term variations in feeding of intertidal fishes are influenced by several interacting time scales. To identify the driver of major variations in the feeding habits of intertidal fish, we used the pemecou sea catfish Sciades herzbergii (Ariidae), an abundant intertidal benthic second order consumer, as a model species. We analyzed the influence of the spring-neap and the day-night cycle on intertidal abundance, stomach fullness, diet composition and food consumption of S. herzbergii using block nets set at slack high tides in two mangrove creeks in north Brazil. At spring tides, intertidal abundance, stomach fullness, and total daily consumption of S. herzbergii were on average 8.8, 1.9, and 3.8 times higher than at neap tides, respectively. At spring tides, Uca spp. and Grapsidae (mostly Pachygrapsus gracilis) dominated the diet, irrespective of the time of day. Other important food items were Insecta and the semiterrestrial crab Ucides cordatus. At neap tides, Capitellidae contributed to the diet of nightly inundations while no specimens were caught at daytime. Creek location had no effect on any variable. Results from our study area and evidence from other studies suggest that the spring-neap tide pulse is likely the major driver of short-to medium term variations in feeding of intertidal fishes. This has important implications for feeding-related issues on macro-and probably also on mesotidal coasts: (i) juvenile fishes may have fortnightly growth spurts, (ii) intertidal prey populations may suffer regular fluctuations in mortality, (iii) studies of the feeding ecology of intertidal fishes should cover the combined effects of the tidal, diel, lunar and seasonal cycles, and (iv) the modeling of food webs should consider the differences between highly dynamic spring tide and quieter neap tide conditions.

Tidal influences on fish distributions on tropical eastern Pacific rocky shores (Colombia)

“…This has also been found in mangrove fishes of Brazil (Brenner & Krumme 2007, Krumme et al 2008. The small changes observed in the subtidal reef fish assemblage over the tidal cycle indicate that intertidal migrations were restricted to just a few species of the entire reef fish assemblage; and even more, to only one part of a population within these specific species.…”

“…In contrast, fishes on coasts with intertidal mangrove or saltmarsh system habitats may greatly benefit from stronger colonisation at spring tides due to relatively large inundated areas with dendritic creek systems and intertidal prey resources concentrated in the higher eulittoral (e.g. Brenner & Krumme 2007, Krumme et al 2008). …”

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“…And the fish species richness, total abundance, total biomass and total abundance and total biomass dominant fish species were significantly changed in seasons in this study (Table 5), which might be caused by different water temperature and salinity in the mangroves of Qinzhou Harbor (Table 7). Krumme et al have already documented that fish abundance, stomach fullness and food consumption were significantly higher in spring tide than the one in neap tide (Krumme and Saint-Paul, 2008). Species richness, total abundance and total biomass of fishes differed significantly between spring tide and neap tide in this study (Table 5), But the fish assemblage structures did not differ significantly between spring tide and neap tide.…”

Dietary overlap and food resource partitioning among fish species of a tropical estuary in Northeastern Brazil

“…In this study, diets of both catfishes (S. herzbergii and S. parkeri) were dominated by Polychaeta and Brachyura crabs. Studies elsewhere on Ariidae species with a similar size range also found a pattern of dominance of the diet by two benthonic preys (Mendoza-Carranza and Vieira 2008), which suggest that the two catfish species forage on or just above the substratum (Krumme et al 2008). This conclusion is consistent with observations ISSN 1981-1268GARCIA & VENDEL.…”