Ongoing activities

Depth-dependent structuring of reef fish assemblages from the shallows to the rariphotic zone

Paris V Stefanoudis1, Erika Gress1, Joanna M. Pitt2, Struan R. Smith3, Todd Kincaid4, Molly Rivers1, Dominic A. Andradi-Brown5,6, Gwilym Rowlands5, Lucy C. Woodall1,5, Alex D. Rogers1,5

1 Nekton Foundation, Begbroke Science Park, Begbroke Hill, Woodstock Road, Begbroke, Oxfordshire OX5 1PF United Kingdom 

2 Department of Environment and Natural Resources, Marine Resources Section, 3 Coney Island Road, St. Georges CR04, Bermuda

3 Natural History Museum, Bermuda Aquarium, Museum and Zoo, 40 North Shore Road, Hamilton Parish FL04, Bermuda

4 Global Underwater Explorers - Project Baseline, Reno Nevada, USA

5 Department of Zoology, University of Oxford, South Parks Road, Oxford OX3 1PS United Kingdom

6 Oceans Conservation, World Wildlife Fund – U.S., 1250 24th St. NW, Washington, D.C., 20037. U.S.A.

Shallow warm-water coral ecosystems are declining worldwide as the result of local and global anthropogenic stressors. As these pressures increase, understanding fish assemblages on deeper reefs becomes more pressing, to determine whether these habitats might act as refugia for shallow-reef populations. We conducted surveys on the Bermuda slope and an adjacent seamount to investigate fish assemblage structure from 15‒300 m depth. Preliminary results, suggest fish biomass and diversity declined with increasing depth, although diversity peaked at the transition from shallow to mesophotic depths (30 m). Fish assemblages were primarily depth-stratified, with distinct suites of species inhabiting shallow (<30 m depth) and mesophotic (upper, 60, and lower, 90 m) habitats and confirming the presence of a rariphotic (~150‒300 m) assemblage. The distinctiveness of the deeper fish fauna reported here highlights the vulnerability of deep reefs to targeted fishing pressure and invasive species and should be considered in future management decisions.

The findings of this work were disseminated during the 5th International Marine Conservation Congress in Kuching, Sarawak, Malaysia, and will be presented during the 15th Deep-Sea Biology Symposium in Monterey, California, USA. A peer-reviewed publication is expected in late 2018/early 2019.

Connectivity between shallow and deeper reef communities in subtropical waters

Paris V. Stefanoudis1*, Molly Rivers1, Helen Ford1, Alex D. Rogers1,2, Lucy C. Woodall1,2

1 Nekton Foundation, Begbroke Science Park, Begbroke Hill, Woodstock Road, Begbroke, Oxfordshire OX5 1PF United Kingdom

2 Department of Zoology, University of Oxford, University of Oxford, John Krebs Field Station,Wytham,OX2 8Q United Kingdom

Benthic megafauna significantly differ depending on depth. From data collected in Bermudian waters using submersibles and technical divers, we explored these relationships for the first time across depths of 15 m to 300 m. Preliminary findings suggest distinct faunal assemblages at each depth with substantial species turnover. This level of differentiation is much greater than has been typically described in the literature, even in areas that are exposed to a high degree of human activities. The assemblages we describe include species that are abundant but new to science and others that are endemic to Bermuda, thus revealing these assemblages are novel. This benthic megafauna heterogeneity includes habitat-forming organisms, has potential implications for the ‘deep reef refugia’ hypothesis and is an important consideration for spatial planning and ocean management.

The findings of this work will be disseminated during the 5th International Marine Conservation Congress in Kuching, Sarawak, Malaysia as well as during the 15th Deep-Sea Biology Symposium in Monterey, California, USA. A peer-reviewed publication is expected in 2018/early 2019.

Changes in zooplankton communities from epipelagic to lower mesopelagic waters

Paris V. Stefanoudis1, Molly Rivers1, Helen Ford1,2, Virginia Grace1, Igor Yashayaev3, Ellen Kenchington3, Alex D. Rogers1,4, Lucy C. Woodall1,4

1 Nekton Foundation, Begbroke Science Park, Begbroke Hill, Woodstock Road, Begbroke, Oxfordshire OX5 1PF United Kingdom

2 School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey LL59 5AB, UK

3 Ocean and Ecosystem Sciences Division, Department of Fisheries and Oceans Canada, Bedford Institute of Oceanography, 1 Challenger Drive, Dartmouth, NS, Canada, B2Y 4A2

4 Department of Zoology, University of Oxford, South Parks Road, Oxford OX3 1PS United Kingdom

Zooplankton are a central component of marine pelagic communities by forming an intermediate trophic link between primary producers (e.g. phytoplankton) and higher trophic levels (e.g. fish). They also exert a significant influence on the vertical transport of carbon through the water column (‘biological carbon pump’) by ingesting, consuming and fragmenting surface-derived particulate organic carbon, and through their diel vertical migrations, mucous feeding webs, molts, carcasses and faecal pellets.  

Presently, the majority of information on zooplankton communities stems from the sunlit epipelagic waters (0‒200 m depth), leaving mesopelagic (200‒1000 m) and deeper pelagic waters, grossly understudied. Consequently, the aim of this project is to assess and document the spatial component of ‘mesozooplankton’ (i.e. retained on a mesh sieve >0.2 mm) communities from 800 m to the surface covering four depth zones: the epipelagic layer (0‒200 m), above the Deep-Scattering Layer (DSL) (200‒400 m), the DSL (400‒600 m), and below the DSL (600‒800 m).

The results of this work are currently being analysed and expected to be published in a peer-reviewed journal in late 2018/early 2019.

Macroplastic pollution

Paris V. Stefanoudis1, Molly Rivers1, Lucy C. Woodall1,2

1 Nekton Foundation, Begbroke Science Park, Begbroke Hill, Woodstock Road, Begbroke, Oxfordshire OX5 1PF United Kingdom

2 Department of Zoology, University of Oxford, South Parks Road, Oxford OX3 1PS United Kingdom

We found 26 litter items from 2,899 images covering an area of 2967 m2. Benthic debris ranged from fishing gear and pipe segments to glass bottles and aluminium cans and polystyrene cups. The results of this work will form part of a synopsis paper that will be published in 2019 and which will provide a synthesis of all the findings of Nekton Mission 1.

Microplastic pollution reporting standards

Molly Rivers1, Lucy C. Woodall1,2

1 Nekton Foundation, Begbroke Science Park, Begbroke Hill, Woodstock Road, Begbroke, Oxfordshire OX5 1PF United Kingdom

2 Department of Zoology, University of Oxford, South Parks Road, Oxford OX3 1PS United Kingdom

Microplastic pollution of Bermuda’s waters is currently being investigated. From Neuston net samples we found on average 63,174 fragments per km2 (14,578‒173,326). This is similar that that seen in previous studies of the region. These data were compared with surface area and weight data to determine the effect of estimating plastic pollution by abundance counts alone. Data suggest that although in most cases microplastic abundance correlates with surface area and weight, a number of samples, particularly when a lot of plastic was present, resulted in significantly larger surface areas and weights of microplastics. The consequence of this is that extrapolations based on microplastic count would result in a total microplastics pollution level at lower than the reality.

Bermuda field ID guide

Paris V Stefanoudis1, Struan R. Smith2, Craig Schneider3, Daniel Wagner4, Molly Rivers1, Gretchen Goodbody-Gringley5, Joana Xavier6, Lucy C. Woodall1,7, Alex D. Rogers1,7 

1 Nekton Foundation, Begbroke Science Park, Begbroke Hill, Woodstock Road, Begbroke, Oxfordshire OX5 1PF United Kingdom 

2 Natural History Museum, Bermuda Aquarium, Museum and Zoo, 40 North Shore Road, Hamilton Parish FL04, Bermuda

3 Department of Biology, Trinity College, Hartford, CT 06106, USA

4 JHT Incorporated, NOAA National Centers of Coastal Ocean Science, 219 Fort Johnston Road, Charleston, SC 29412, USA

5 Bermuda Institute of Ocean Sciences, 17 Biological Lane, St. Georges, Bermuda GE01

6 Department of Biological Sciences and K.G. Jebsen Centre for Deep-Sea Research University of Bergen, Bergen, Norway

7 Department of Zoology, University of Oxford, South Parks Road, Oxford OX3 1PS United Kingdom

We are currently preparing a photographic guide for the visual identification of the corals, marine plants and other common invertebrates that inhabit Bermuda’s seafloor building on the video and imagery data collected during Nekton Mission 1 in Bermuda. For each entry we will provide information on its distribution and depth range based on our work only, accompanied by a short morphological description and some representative images. The resulting faunal guide will be designed to aid marine biologists, divers and naturalists with the identification of organisms as seen in underwater footage or live in the field.

Surface Zooplankton Communities from Bermuda

Molly Rivers1, Paris V Stefanoudis1,  Lucy C. Woodall1,2

1 Nekton Foundation, Begbroke Science Park, Begbroke Hill, Woodstock Road, Begbroke, Oxfordshire OX5 1PF United Kingdom

2 Department of Zoology, University of Oxford, South Parks Road, Oxford OX3 1PS United Kingdom

We also sampled the topmost surface layer (0‒0.5 m) with a single Neuston frame system (SEA-GEAR; mouth opening 0.5 m2, net mesh size: 300 μm) in several locations in the NW Atlantic (Bermuda, the Gully region on the Scotian Shelf, Kelvin Seamount, Gulf Stream Frontal Area). Data has been collected, and currently, we are performing statistical analysis. The results of this work will form part of a synopsis paper that will be published in 2019 and which will provide a synthesis of all the findings of Nekton Mission 1. Below, you can see some representative fish larvae found in our samples.

Zooplankton communities from the SW Indian Ocean

Molly Rivers1, Paris V Stefanoudis1,  Lucy C. Woodall1,2

1 Nekton Foundation, Begbroke Science Park, Begbroke Hill, Woodstock Road, Begbroke, Oxfordshire OX5 1PF United Kingdom 

2 Department of Zoology, University of Oxford, South Parks Road, Oxford OX3 1PS United Kingdom


We used a Hydrobios MultiNet MiDi zooplankton sampler (mouth opening 0.25 m2, net mesh size: 180 µm) to sample the water column at 5 pre-defined depths in the Southwest Indian Ocean. These depths correlate to the Florescence Maximum (F-Max) with two above (0-50; 50–100 m), one within (100–150 m) and two below the F-Max (150–200; 200–250 m). The zooplankton assemblages at each depth are currently being processed and analysis is expected to finish by the end of 2018.