Diversity and Composition of Demersal Fishes along a Depth Gradient Assessed by Baited Remote Underwater Stereo-Video

Abstract

BackgroundContinental slopes are among the steepest environmental gradients on earth. However, they still lack finer quantification and characterisation of their faunal diversity patterns for many parts of the world.Methodology/Principal FindingsChanges in fish community structure and diversity along a depth gradient from 50 to 1200 m were studied from replicated stereo baited remote underwater video deployments within each of seven depth zones at three locations in north-eastern New Zealand. Strong, but gradual turnover in the identities of species and community structure was observed with increasing depth. Species richness peaked in shallow depths, followed by a decrease beyond 100 m to a stable average value from 700 to 1200 m. Evenness increased to 700 m depth, followed by a decrease to 1200 m. Average taxonomic distinctness △+ response was unimodal with a peak at 300 m. The variation in taxonomic distinctness Λ+ first decreased sharply from 50 to 300 m, then increased beyond 500 m depth, indicating that species from deep samples belonged to more distant taxonomic groups than those from shallow samples. Fishes with northern distributions progressively decreased in their proportional representation with depth whereas those with widespread distributions increased.Conclusions/SignificanceThis study provides the first characterization of diversity patterns for bait-attracted fish species on continental slopes in New Zealand and is an imperative primary step towards development of explanatory and predictive ecological models, as well as being fundamental for the implementation of efficient management and conservation strategies for fishery resources.

Comparison of baited longlines and baited underwater cameras for assessing the composition of continental slope deepwater fish assemblages off southeast Australia

“…This possibility was corroborated by BRUVs vision, which showed persistent E. cirrhatus activity at the bait bag. Hagfish have an elaborate cutaneous chemosensory system (Braun and Northcutt, 1998) and have previously been found to arrive at baited camera systems earlier than other species (Martinez et al, 2011) where they show high levels of activity (Zintzen et al, 2011(Zintzen et al, , 2012. On this basis, one presumes they also would arrive early at baited hooks too, making baits unavailable to other fish.…”

“…Langlois et al, 2010;McLean et al, 2010McLean et al, , 2011Watson et al, 2009Watson et al, , 2010Harvey et al, 2012Harvey et al, , 2013. The potential of this technique to provide data on continental slope fish communities is illustrated by a recent study to depths of 1200 m off New Zealand (Zintzen et al, 2012).…”

Assessing hotspots within hotspots to conserve biodiversity and support fisheries management

“…Major changes in the assemblage composition are known to occur along that depth gradient (Menezes et al 2006). The use of baited remote underwater video systems is a non-invasive method to study fish assemblages at greater depths (Zintzen et al 2012). This method is currently being tested in our study region and may enable expanding predictive modelling to deeper habitats in the future.…”

A Comparison of Fish Community Structure at Mesophotic Artificial Reefs and Natural Banks in the Western Gulf of Mexico

“…Environmental factors, including bottom depth and vertical relief, have often been identified as important drivers of fish community structure at natural and artificial reef habitats (Gallaway et al 1981;Stanley and Wilson 2000;Wilson et al 2003;Zintzen et al 2012;Bryan et al 2013;Patterson et al 2014). Seminal work by Gallaway et al (1981) classified standing platform communities across the Texas-Louisiana shelf into three groups: a coastal group (<30 m), an offshore group (30-60 m), and a blue water group (>60 m).…”