Diet shift response in round goby,Neogobius melanostomus, based on size, sex, depth, and habitat in the western basin of Lake Erie

Abstract

Summary This study examines the diet of the round goby (Neogobius melanostomus) in the western basin of Lake Erie. As an invasive benthic feeder, the round goby has the potential to affect smallmouth bass and other native species. Round goby (n = 100) were collected during summer 2011 and stomach contents were examined to determine diet patterns and possible ontogenetic diet shifts. Individual round goby were grouped by sex, size (small < 65 mm, large ≥ 65 mm), depth of habitat (shallow < 2 m, deep > 5 m), and habitat type (natural shallows, anthropogenically modified shallows, and deep waters). Gut fullness ranged from 10 to 100% with 23 stomachs presenting 100% fullness. Round goby consumed 27 different food items including abiotic (sand grains, gravel), floral (algae, fine leaved vascular plants), and fauna items. The Index of Relative Importance (IRI) and comparative z‐tests were used to assess correlations and differences. Two‐way z‐tests revealed a significant difference in mouth gape related to size (z = −5.56377, P = 2.64e‐08), and habitat depth (z = 3.34262, P = 0.00083). A significant linear correlation was also found between mouth gape standardized by head length (HL) for both males (P = 2.63e‐9) and females (P = 1.3e‐4). Two‐way z‐tests also revealed a significant difference in gonadosomatic index (GSI) related to sex (z = 6.07727, P = 6.11248e‐10), but not size. A significant difference in gut fullness was also found related to sex (z = −3.34743, P = 0.00082), habitat depth (z = 3.16336, P = 0.00156), and habitat type (z = −2.7398, P = 0.00615). IRI values demonstrated a diet selective of veliger mussels (IRI = 2462.01), juvenile mussels (IRI = 1073.03), cladocerans (IRI = 4804.31), and chironomids (IRI = 1012.12). While previous studies have focused on round goby diet shifts from macroinvertebrates to bivalves, most studies did not evaluate changes in diet among multiple categories. Furthering knowledge of multiple aspects of goby diet may aid in developing management techniques to deter future round goby invasion.

A dynamical model for invasive round goby populations reveals efficient and effective management options

“…The number of available nests and the sex ratio are both important factors affecting reproduction because of round goby's nest guarding strategy (Meunier et al., ). A challenging issue is that the observed sex ratio can be biased by the catch technique (Brandner, Pander, Mueller, Cerwenka, & Geist, ; Thompson & Simon, ) and by invasion stage. Because of a lack of own field data and unclear literature values (N'Guyen et al., ), in our model we assumed equal proportions of removed males and females (Figure in Appendix ).…”

Age and growth of round goby Neogobius melanostomus associated with depth and habitat in the western basin of Lake Erie

“…melanostomus to be equally abundant in open‐lake deep water (>5 m) as in natural shallows (<2 m). This could be explained by the availability of open areas in deep water habitats in which to forage (Thompson & Simon, ), temperature preference or gear bias. Johnson et al () found 55·6% of the Lake Erie N .…”

“…This study, however, found N. melanostomus to be equally abundant in open-lake deep water (>5 m) as in natural shallows (<2 m). This could be explained by the availability of open areas in deep water habitats in which to forage (Thompson & Simon, 2014), temperature preference or gear bias. Johnson et al (2005) found 55⋅6% of the Lake Erie N. melanostomus population occurred offshore due to area availability, while overall density was found to be 3⋅8 times greater along coastal shorelines than offshore from 1995 to 2002.…”

Zoochorous dispersal of freshwater bivalves: an overlooked vector in biological invasions?

“…Age, genetic and environmental factors are suggested to influence pharyngeal remodelling. Moreover, Index of Relative Importance analysis of N. melanostomus gut contents indicate a diet selective of veliger and juvenile dreissenid mussels (Thompson and Simon, 2014). In contrast, I. furcatus appears to be preferentially more piscivorous, although it is often described as an omnivorous opportunistic feeder (MacAvoy et al, 2000;Aguilar et al, 2016).…”