Interactions between adult and larval bluegill sunfish: positive and negative effects

Abstract

Adult fish may affect the growth and survival of conspecific larvae through a variety of pathways, including negative interactions via competition for shared limiting resources or via predation (i.e., cannibalism), and positive interactions due to the consumption of larval predators and via resource enhancement (i.e., presence of adults increases availability of larval prey). To examine the overall effect of adult bluegill sunfish (Lepomis macrochirus) on larval bluegill, we conducted a field experiment in which we manipulated adult densities and quantified larval growth and survival, prey abundance, invertebrate predator abundance, and cannibalism. The presence of adult bluegill had a negative effect on final larval mass. This response was consistent with competition for zooplankton prey. Adult bluegill reduced the abundance of large zooplankton (e.g., Chaoborus and Daphnia), which were the dominant prey of bluegill larvae in the absence of adults. Larvae in the no-adult treatment also had significantly more prey in their stomachs compared to larvae in the presence of adults. Larval survival was maximized at intermediate adult densities and the overall production of larvae peaked at intermediate adult densities. The higher larval survival at intermediate adult densities is attributed to a reduction in invertebrate predators in treatments with adult bluegill; invertebrate predators experienced an 80% reduction in the presence of adult fish. Decreased larval survival at the highest adult density was not due to resource limitation and may be due to cannibalism, which was not directly observed in our study, but has been observed in other studies.

Bluegill (Lepomis macrochirus) Spawning Periodicity and Hatching Duration in the Northern Great Plains, USA

“…As a result, direct comparisons to previous research are challenging. Interacting factors may include abiotic factors such as physical habitat, temperature, and weather (Beard 1982, Pope et al 1996, Jackson and Noble 2000, Casselman et al 2002 and biotic factors such as food availability and competition (Partridge andDeVries 1999, Rettig andMittelbach 2002), predation (Houde 1987, Gray et al 1998, and lake productivity (Latta and Merna 1977).…”

Egg characteristics and larval growth of bluegill from stunted and non-stunted populations

“…Environmental factors such as nutritional status (Izquierdo et al 2001) and stress (Schreck et al 2001) can cause plasticity in egg properties. In the wild, the larval bluegill growth has been shown to vary with zooplankton community composition (Wittenrich et al 2009), and generally increases with declining adult density (Rettig & Mittelbach 2002), increasing zooplankton abundance (Welker et al 1994), decreasing gizzard shad (Dorosoma cepedianum) density (Oplinger et al 2013), and increasing temperature (Belk and Hales 1993). Such environmental effects may be important in determining the growth of larval bluegill in the wild but were likely obscured by the controlled conditions (i.e., similar temperature, food resources, and predation pressure) in our experimental mesocosms.…”

Effects of a native crayfish (Orconectes virilis) on the reproductive success and nesting behavior of sunfish (Lepomis spp.)

“…Kellogg Biological Station (KBS) in southwestern Michigan. The ponds are bowl-shaped, having a maximum depth of 2 m and a diameter of 29 m. The biota of these ponds is representative of that that found in nearby natural lakes and ponds, and the ponds contain a diverse assemblage of macrophytes, plankton, and benthic invertebrates (e.g., Crowder and Cooper 1982;Rettig and Mittelbach 2002;Dorn and Wojdak 2004). Water levels fluctuate little year-round and the ponds can support permanent populations of sunfish unless purposefully drained.…”

“…YOY fish were sampled in July and September 1999. In July (when fish were very small) we sampled with a window-screen seine (2.3 m × 2.9 m with 1.8 mm mesh) attached to two wooden poles and operated by two swimmers (as in Rettig and Mittelbach 2002). The seine was placed in the middle of the pond and swum through the water towards shore, seining one radius of the pond.…”