Size-specific social interactions and foraging styles in a shallow water population of mutton snapper,Lutjanus analis (Pisces: Lutjanidae), in the central Bahamas

Abstract

SynopsisField observations quantified the effects of fish size and time of day on activity patterns, intraspecific encounters, and foraging styles in mutton snapper, Lutjanus analis, during the spring and winter of 1991. Fish ranged in size from 15 to 65 cm fork length (FL), and were associated with an artificial patch reef system located on a shallow seagrass meadow in the Exuma Cays, Bahamas. The most common, non-resting diurnal activities were intraspecific chasing and displacing, and feeding. Intraspecific displacing was significantly higher during midday compared to morning or evening. The highest proportion of intraspecific encounters (combined chasing and displacing events) occurred among medium (25-35 cm FL) and large (> 35 cm FL) fish. The few large fish observed (13% of population) initiated the same proportion of encounters as the predominant (50%) medium fish. The remaining (37%) small fish (> 25 cm FL) were the least aggressive. Dark barred and dark nape color patterns were associated with displacing and chasing, respectively. Fish exhibited considerable variability in feeding behavior. Proportionally fewer fish fed during midday compared to morning or evening, although small fish fed proportionally more often than medium or large fish despite time of day. Picking was the primary feeding mode and was observed during all times of day. Winnowing was observed during midday and evening, whereas midwater strikes were confined to morning and evening. Small fish displayed proportionally higher picking and midwater strikes during morning and evening, respectively, compared to medium or large fish. However, large fish winnowed proportionally more often than small or medium fish during evening. Dark barred color patterns were associated with feeding on the substrate, whereas no color changes occurred during midwater strikes. Our results indicate that L. anafis forms dominance hierarchies and that high variability in foraging styles, according to fish size and time of day, may be a means to reduce intraspecific competition.

Diel and habitat-dependent resource utilisation of deep-sea fishes at the Great Meteor seamount (subtropical NE Atlantic): niche overlap and support for the sound-scattering layer-interception hypothesis

“…Ontogenetically determined shifts in habitat utilisation, in terms of intraspecific competition, with corresponding spatial displacements have been analysed (e.g. Mueller et al 1994, McCormick 1995.…”

Behavioral and ontogenetic colour changes of a poorly known lutjanid

“…the common bluestripe snapper Lutjanus kasmira (Forsskål, 1775), their potential predators can become visually confused and not able to distinguish one individual from Colour changes of Lutjanus alexandrei 907 another (Randall 2005;Price et al 2008;Pereira et al 2011a). Vertical bars, like those seen in Figure 2A, C and F, are hypothesized to be associated with foraging behaviour, as this type of colouration resembles the vertical growth of vegetation (Mueller et al 1994;Deloach 1999), dominant in most of the feeding grounds of L. alexandrei. When this species goes over a sandy bottom, its bars fade away and the fish becomes less conspicuous.…”

“…For reef fishes they have often been observed in scarids, serranids and lutjanids (Gilmore & Jones 1992;Mueller et al 1994;Erisman & Allen 2005;Kline et al 2011). In these fishes, colour displays are associated with social hierarchy (Gilmore & Jones 1992;Mueller et al 1994;Mumby & Wabnitz 2002;Muñ oz & Warner 2003) and reproduction, for agonistic encounters between males (Kline et al 2011) or sexual recognition (Hamamoto et al 1992;Sadovy & Eklund 1999). These ephemeral changes usually occur in head colouration, body contrast patches and fin edges (Kodric-Brown 1998).…”

Feeding ecology of Lutjanus analis (Teleostei: Lutjanidae) from Abrolhos Bank, Eastern Brazil

“…mouth gap), affecting prey size selectivity, a result already recorded for L. apodus (Roocker, 1995). In the other hand, it is important to consider that juveniles and adults of L. analis display different foraging styles, where small individuals displayed proportionally higher picking and midwater strikes during morning and evening, whereas individuals large winnowed proportionally more often than small or medium fish during evening (Mueller et al, 1994).…”

“…Available evidences indicate that the diet of L. analis include fishes, shrimps, crabs, gastropods, and cephalopods (Allen, 1985;Heck & Weinstein, 1989;Claro & Lindeman, 2004;Pimentel & Joyeux, 2010), a general pattern for the family Lutjanidae (Duarte & Garcia, 1999;Santamaría-Miranda et al, 2003;Lee & Szedlmayer, 2004;Rojas-Herrera et al, 2004;Molina et al, 2005). Although snappers are generally considered nocturnal predators (Claro & Lindeman, 2004), L. analis fed diurnally (Watanabe, 2001), showing a high variability in foraging styles, according to fish size and time of day (Mueller et al, 1994).…”