Diel shifts in the structure and function of nearshore estuarine fish communities

Abstract

Day-night shifts in the nearshore fish fauna of a temperate microtidal estuary were assessed using a holistic suite of structural and functional community attributes. Mean fish species richness and diversity (taxonomic distinctness) were higher at night across all regions of the estuary and seasons, concurring with the findings of numerous comparable studies reviewed worldwide, while the diel period in which mean abundance was higher varied among seasons. Likewise, species and functional guild compositions (the latter based on feeding modes and habitat use) both differed significantly between day and night, with the extent of the diel shift again varying seasonally. Daytime fish communities were characterized by higher abundances of Atherinidae, Sillaginidae and Mugilidae, while Gobiidae were far more abundant at night. Marked shifts in size composition were also evident, with smaller fishes (<100 mm total length, L ) being more prevalent during the day and larger fishes (≥200 mm L ) proportionally more abundant at night. The above diel shifts were feasibly related to a range of predator-prey interactions and feeding-related movements, namely a nocturnal decrease in top-order avian piscivory coupled with an increase in invertebrate prey availability, resulting in changes in the presence and catchability of certain fish species in shallow estuarine waters.

The effect of algal blooms on fish in their inshore nursery grounds in the Gulf of Gdańsk

“…In June, we observed the occurrence of large individuals of cod, sculpin, flounder and turbot, usually present in a shallowwater area during the night (Lizińska, 2002). Similar regularity was observed during studies of diel shifts conducted by Yeoh et al (2017) in nearshore estuaries where small pelagic fishes were more abundant during the day, while larger pelagic, benthic-pelagic and demersal fishes prevail at night.…”

“…Similar regularity was observed during studies of diel shifts conducted by Yeoh et al . (2017) in nearshore estuaries where small pelagic fishes were more abundant during the day, while larger pelagic, benthic-pelagic and demersal fishes prevail at night.…”

Influence of feeding frequency on diurnal variations in liver and muscle RNA/DNA ratios in Misgurnus anguillicaudatus

“…Previous studies have suggested that the feeding of aquatic animals, for example, the Yangtze finless porpoise ( Neophocaena asiaeorientalis asiaeorientalis ), was affected not only by environmental factors but also by their diel rhythm (Wang, Akamatsu, Wang, & Wang, 2014; Yerushalmi & Green., 2009). Studying the feeding rhythm of aquatic animals can help adjust the feeding times of cultured species and rationing to improve feed utilization (Yeoh, Valesini, Hallett, Abdo, & Williams, 2017). Specifically, modifying the feeding rhythm could improve animal feeding activity by allowing feed protein to be more readily used for growth, which is of significance in farmed aquatic animal feeding (Gelineu, Medale, & Boujard, 1998).…”

Fish-based indicators of estuarine condition that do not require reference data

“…For ABC analysis to provide an accurate indication of environmental condition, the sampling regime must obtain a representative sample of organisms across their full size range (Warwick, 1986). In the current study, ABC analyses were based, however, on samples from just nearshore, shallow waters (< 1.5 m deep), which are dominated by small-bodied species (Hoeksema et al, 2009;Potter et al, 2016;Yeoh et al, 2017). In contrast, the offshore, deeper waters typically contain far greater numbers of larger-bodied individuals (Paterson and Whitfield, 2000;Munsch et al, 2016).…”