New photographic equipment aboard the research vessel Dr. Fridtjof Nansen improves species identification
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| Plesionika williamsi, photographed using the new equipment onboard the R/V Dr. Fritdjof Nansen © Keider Neves. |
Photography of marine fishes and invertebrates plays a crucial role in identifying and documenting biodiversity and has a wide field of applications. High-quality images of fresh specimens are essential in new species’ descriptions, morphological studies, field guides, preparation of scientific illustrations, and in training the next generation of taxonomists.
To enhance the quality of photographic documentation of marine species on board the research vessel (R/V) Dr. Fridtjof Nansen, a photo tank consisting of a narrow, vertically orientated aquarium paired with LED daylight panels and a tripod-mounted digital single-lens reflex camera was used during the recent research surveys in northwest Africa and the Western Gulf of Guinea.
Onboard, specimens in the best condition with vivid color, intact fins, or limbs, were selected from the trawl catches. Given that color fades quickly, specimens were immediately photographed and later processed and sampled for identification. If unable to be immediately photographed, specimens were kept cold in the fridge to keep them from drying out.
A photo tank allows scientists to immerse specimens in seawater, which eliminates surface reflections, glare, and shadows. Specimens are photographed in left lateral view against a uniform black background placed behind the photo tank.
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| Photography lab onboard the R/V Dr. Fritdjof Nansen © Katherine Bemis | |
The above photo tank method uses a plexiglass insert with holes drilled through it to suspend the specimen in the middle of the tank. Pins are inserted through the holes of the insert into the fish body and fins to hold them in place before submersion in the tank. This prevents the specimen from moving once placed in the tank, but it can be challenging and time consuming with fishes presenting tough and/or prickly scales or invertebrates with stony carapace.
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| Dame Ndiaye from Senegal (left) and Oussama Rbiai from Morocco (right), pins fish fins in preparation for photography © Katherine Bemis | |
Clarity of water is important to take quality photographs. Before beginning the pinning process, specimens are rinsed thoroughly with seawater to remove things like mucous, debris, dirt, and loose scales. A small paintbrush or pipet are used for popping air bubbles after specimen submersion in the tank as well as for removing small particles of debris from the specimen’s body.
Although most fishes share a laterally compressed body plan that is conventionally photographed in lateral view, some groups have dorso-ventrally compressed bodies, like rays, monkfishes, and flatfishes, and necessitate dorsal and ventral views to observe their morphology. For this scope, two shallow, horizontally orientated aquariums (one for small and one for medium-size specimens) paired with a close-up copy stand to suspend the camera over the photo tank will soon be available on board the vessel. This setup also fits the photographic requirements of some invertebrate groups such as crabs, mantis shrimps, slipper and squat lobsters.
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| Examples of a laterally compressed fish Xyrichtys novacula (left) and of a dorsoventrally compressed fish Torpedo torpedo (right). The photograph of Xyrichtys novacula was taken submerged in the new photo tank, whereas the Torpedo torpedo photograph was taken on the ship deck © Katherine Bemis and Peter Psomadakis | |
In a research context, high-quality photographs can enable verification of taxonomic identification without physical examination as the images confer high resolution details of color, anatomical features, including meristic characters like scale counts, that can be clearly observed when enlarging the photograph. This makes it possible for taxonomic experts globally to assist in identifications remotely.
Importantly, photographed specimens were also tissue sampled and retained for deposition in museum collections. This will allow scientists to refine identifications based on anatomical and genetic data, describe new species, publish new range records, and improve future at sea identifications.
Correct species identification is essential for fisheries management as well as biodiversity assessments. The scientific team participating in the recent surveys by the R/V Dr. Fridtjof Nansen in northwest Africa and the Western Gulf of Guinea included fish taxonomists Katherine Bemis from the NOAA Fisheries National Systematics Lab and Smithsonian Institution, and Peter Psomadakis, taxonomist at FAO, as well as invertebrate taxonomists Marta Gil from the University of Vigo in Spain, and Keider Neves from Biosfera in Cabo Verde.
In addition to supporting the national scientists and staff from the Norwegian Institute of Marine Research (IMR) that are operating the vessel with the identification of species in the trawl catches, the taxonomists provided hands-on training on species identification and scientific photography. The new photography method adopted on the R/V Dr. Fridtjof Nansen was shared with the national scientists participating in these surveys and a dedicated workshop was organized for this scope. Overtime, photographs taken onboard the vessel will be developed into regional identification guides to continue to improve at-sea identifications.
About the Programme
The R/V Dr. Fridtjof Nansen is at the center of the EAF-Nansen Programme, a longstanding partnership between the FAO and Norway, executed in close collaboration with IMR. In collaboration with 32 countries across Africa and the Bay of Bengal, the Programme is improving fisheries policies and management practices in line with the ecosystem approach to fisheries and developing the capacity of fisheries institutions to ensure sustainable fisheries management.
The Programme aligns with the objectives of the UN Decade of Ocean Science for Sustainable Development, as well as FAO's vision for the Blue Transformation of aquatic food systems for better production, better nutrition, a better environment, and a better life for all.
More information:
- Advancing biodiversity research with discovery of new fish species in Myanmar (web story)
- Fish taxonomy research workshop develops local talent and leadership in Tenerife (web story)
- Discovery of a new species of giant guitarfish in Bangladesh raises country’s ambition about solid taxonomic research (web story)
- Building Africa’s capacity for better fisheries management through taxonomy and marine species identification (web story)
- First regional training course on marine taxonomy and species identification took place in Southeast Asia (web story)
- Post-survey Taxonomy Training, Tenerife (January 2023) (photo collection)
- Description of two new species of sandlances, genus Bleekeria (Perciformes, Ammodytidae) from the Andaman Sea (northeastern Indian Ocean) (scientific paper)
- Two new species of the genus Chelidoperca (Perciformes: Serranidae) from the Andaman Sea, eastern Indian Ocean (scientific paper)
- Grammatonotus bianchi, a new species of splendid perch (Percoidei: Callanthiidae) from Myanmar, northeastern Indian Ocean (scientific paper)