Bait type affects fish assemblages and feeding guilds observed at baited remote underwater video stations

Abstract

Baited remote underwater video stations (BRUVS) are increasingly being used to examine assemblages of fishes, yet critical methodological questions related to sampling limitations and bias, such as the influence of bait type, remain poorly understood. At multiple locations, we examined the hypothesis that diversity and abundance in temperate reef fish assemblages were independent of bait type. We used 3 bait types (abalone viscera, pilchards and crushed urchin) and quantified commonly used metrics for the fish assemblage, including species richness, time of first arrival and relative abundance on 3 shallow rocky reefs in southeastern Australia over 2 yr. We distinguished the following 6 feeding guilds: herbivore, zooplanktivore, alga/ invertebrate consumers, invertebrate carnivore, macroinvertebrate carnivore and generalist carnivore. The response of fishes was dependent on bait type, with urchin bait performing particularly poorly. Although we did not detect statistical differences between the performance of pilchards and abalone viscera as bait, pilchards produced more consistent outcomes. Importantly, we also observed strong spatial effects. In general, bait type had a marked effect on species richness, but little influence on relative abundance. Overall we conclude that oily bait such as pilchards, which have been widely used in most studies, yield the most consistent outcomes. Consequently, bait type and spatial variation in fish assemblages needs to be considered in sampling designs to assess the limitations of BRUVS. This article was originally published as: Wraith, J., Lynch, T., Minchinton, T. E., Broad, A. & Davis, A. R. (2013). Bait type affects fish assemblages and feeding guilds observed at baited remote underwater video stations. Marine Ecology: Progress Series, 477 189-199. 2.Abstract: Baited Remote Underwater Video Stations (BRUVS) are increasingly being used to examine assemblages of fishes, yet critical methodological questions related to sampling limitations and bias, such as the influence of bait type, remain poorly understood. At multiple locations, we examined the hypothesis that diversity and abundance in temperate reef fish assemblages were independent of bait type. We used three bait types (abalone viscera, pilchards and crushed urchin) and quantified commonly used metrics for the fish assemblage including species richness, time of first arrival and relative abundance on three shallow rocky reefs in southeastern Australia over 2 years. We distinguished the following six feeding guilds: herbivore, zooplanktivore, algae/invertebrate consumers, invertebrate carnivore, macroinvertebrate carnivore and generalist carnivore. The response of fishes was dependent on bait type with urchin bait performing particularly poorly. Although we did not detect statistical differences between the performance of pilchards and abalone viscera as bait, pilchards produced more consistent outcomes. Importantly, we also observed strong spatial effects. In general, bait type had a marked effect on species ...

Rules of attraction: enticing pelagic fish to mid-water remote underwater video systems (RUVS)

“…An expanding body of literature has critically evaluated the BRUVS methodology, examining optimal length of deployment (Stobart et al 2007, Gladstone et al 2012, bait types (Wraith et al 2013), quantities of bait (Harvey et al 2007, Hardinge et al 2013) and the influence of time of day (Birt et al 2012). …”

Do predatory fish of benthic crustaceans vary between kelp and barren reef habitats in northeastern New Zealand?

“…The limited observation period used in this study may also have resulted in an underestimation of more cryptic or less mobile species that may have been present in this study, e.g. the territorial spotted wrasse (Wraith et al 2013). Additionally, the threedimensional structure of kelp habitat may have interfered with the dispersion of bait odour plume and, as a result, the benthic-feeding fish assemblages might have varied as a result of variation in the dispersal of the plume from the bait.…”

“…The greater abundance of benthic predator species in barren habitat could suggest greater predation risk for benthic crustaceans in this habitat; however, BUV can overestimate the abundance of some species due to a strong attraction by a particular bait type Wraith et al 2013). Some species were not strongly attracted to the bait plume, such as red moki, which is otherwise known as an important benthic-feeding species (Leum & Choat 1980;Taylor 1998).…”

“…A perforated 500 mL transparent plastic container (polyethylene terephthalate) was used as a bait box and attached to a metal bar 40 cm in front of the camera (Figure 2). Immediately prior to deployment, the bait box was filled with 200 g of chopped frozen pilchard (Sardinops neopilchardus) Wraith et al 2013). The camera device with the attached bait container was lowered to the seafloor from a boat using a rope attached to the device and a surface float at the other end (Edgar et al 2004).…”

Animal v. plant‐based bait: does the bait type affect census of fish assemblages and trophic groups by baited remote underwater video (BRUV) systems?

“…While previous studies have mainly focused on comparison of BRUV and other sampling methods [ e.g . unbaited remote underwater video (Watson et al , ; Harvey et al , ), trawls (Cappo et al , ), hook and line (Brooks et al , ), underwater visual census (Colton & Swearer, )], few studies have examined the efficiency of different bait types for BRUV sampling (Wraith et al , ; Dorman et al , ) and only a recent study (Dorman et al , ) compared ABs and plant‐based baits (PBs).…”