Diario del proyecto Australasian Fishes

Archivos de diario de abril 2018

06 de abril de 2018

Member profile - Clinton Duffy

Perhaps as a result of the wide range of movies from Jaws to Sharkanado, it would be difficult to imagine anyone over the age of five, who has not, at one point in their life, thought deeply about sharks, either out of concern or in appreciation for the beauty and adaptability of this class of ancient fishes. Sharks loom large in our collective imagination, and when reading project Bio Blurbs of other project participants, you will often see references about their admiration or appreciation for sharks and their cartilaginous cousins. Because of this almost universal interest, the project is extremely grateful for the participation of a professional scientist such as Clinton Duffy, known as @clinton, who has willingly become the project’s shark expert, and is frequently called upon to identify images of sharks, rays and even fragments of cartilage. As with many participants in the project, his interest in nature stems from a rural upbringing and school holidays spent on isolated parts of the Wairarapa coast, New Zealand. His interest in fishes started from splashing around in rock pools and waiting on the beach for his father and his friends to get back from fishing trips. He began free-diving at age 12 and his SCUBA qualifications at 15.
To Clinton, every week is Shark Week. He works in the Marine Ecosystems Team, Biodiversity Unit, New Zealand Department of Conservation, based in Auckland. His role is to provide science and technical advice on marine conservation issues and species, particularly marine protected areas, marine ecology and human impacts on the marine environment, and chondrichthyan fishes (sharks, rays and chimaeras). In addition Clinton is also a Marine Associate of the Auckland Museum and a part-time PhD student at the University of Auckland studying the movements and population size of white sharks (Carcharodon carcharias).
Unlike many in the project, Clinton is not a photographer, so on the leader board, he ranks at number 23 for total observations. However, he plays a pivotal role in the project as our shark subject matter expert, ranked as Number 5 in Identifications, with a total of 3,874 at the time of this writing. While working, studying and raising a family he makes an extremely generous donation of his professional expertise to Australasian Fishes and has been a source of inspiration and assurance to many in the project, especially with his identification of sharks.
While Clinton indirectly shares his scientific expertise through his comments and identifications in the project, he is a vast storehouse of knowledge on this captivating topic. Rather than publishing a traditional Bio Blub, I would like to share Clinton’s responses to recent questions about his professional interests, sharks and working in New Zealand:
1. As one of the actual scientists, in the project, could you give some advice to participants about the importance of citizen science, and how there is potential for helping professionals like you?

My reaction to this question is that platforms such as iNaturalist are extremely useful in terms of encouraging engagement with the natural world, particularly as people become increasingly urbanised. Citizen scientists are often in places that professional biologists find difficult to access, or are able to capture chance observations of rarely seen species or events. The growth in value of citizen science really parallels the growth of platforms such as iNaturalist and the accessibility of high quality digital cameras. Now people are readily able to document in detail their observations and move them from the realm of anecdote to fact. Ultimately the value of iNaturalist depends on the number, spatial coverage and continuity of the contributions made to it. For example, my most recent paper was on courtship behaviour in Mobula japanica. That paper and my record of Mobula tarapacana from Australia (Zootaxa 4126 (1): 141–145) are examples of collaborations with citizen scientists. In each case my co-author is a recreational fisher that happened to be in the right place at the right time with a pole camera.

2. Could you give some advice about photographing sharks? How to act, best places/conditions to position yourself?

The easiest and safest places to photograph sharks of course depend on the species you want to photograph. The vast majority of species are harmless so questions around safety to revolve around the environmental conditions prevailing at the site (e.g. depth - dictates bottom times and decompression, temperature, currents and wave action). The best places to photograph sharks are generally going to be at aggregation sites, or places where you get concentrations of potential prey.

Coral reefs generally provide opportunities to photograph multiple species. Walls, drop-offs and passes are generally inhabited by species such as grey reef, whitetip reef, silvertip and lemon sharks, and occasionally hammerheads and tigers. Lagoons generally contain whitetip and blacktip reef sharks, as well as rays. Shallow seamounts and oceanic islands in the tropics usually provide opportunities to see Galapagos, silky, oceanic whitetip and scalloped hammerheads.

Of course, it’s always best to go with someone with good knowledge of the area you want to dive. It can take time to learn where a particular species likes to hang out in any given place.

Chumming and free swimming with pelagic sharks (e.g. blues, mako, silky) can be done safely but it takes careful thought and planning, a cage or platform that divers can retreat to and exit the water from safely, dedicated safety divers and a watchful, competent skipper.

3. Any tips you’d be willing to offer about shark ID. What are the best features to observe on a fish to narrow down a particular ID?

For any species it is attention to detail that allows a positive identification to be made, or a previously undescribed species to be recognised. The external characters that are important for the identification of sharks and rays are:

(a) body shape
(b) the relative positions and sizes of the fins
(c) colour patterns, including markings on the fins or the margins of the fins
(d) the presence-absence of raised ridges of skin between and in front of some of the fins
(e) presences of nodules and ridges on the head
(f) shape of the nasal flaps
(g) size and shape of the teeth
(h) presence-absence of rows or patches of thorns (rays)
(i) size and shape of the male's claspers (mainly skates)
A good lateral shot of the entire fish (from above for rays) is the starting point.

4. What about behaviours divers should follow when encountering sharks?

I generally find the best way to observe any wildlife is to pretend you're not interested in them. Chasing or swimming directly at a shark usually results in it bolting away. I have been in the water with more than twenty sharks (Galapagos sharks) at a time with few concerns. It is not the number of sharks present but their behaviour that should dictate when you get out. Rapid, agitated swimming, darting about or at divers are all signs that you should get out of the water.

5. I understand you go on research cruises. Can you tell us a little about the work you do at sea, what is life on research ships like and do you find them interesting/enjoyable?

Research cruises are both extremely enjoyable and challenging. Finding funding to secure a place for you and your research agenda on a cruise is usually the first challenge, the second is often the environmental conditions encountered (the sea is seldom as portrayed in the ads for that tropical island vacation). Time is always at a premium so expeditions usually involve long hours of specimen/sample curation and data entry. The physical challenge is something that is often overlooked but hits home fairly quickly for someone like me that flies a desk most of the time but the payoff is the chance to visit parts of the world and see species that few will people will ever get the chance to see first-hand.

6. Your research on great white migrations sounds very interesting. What is the research regarding and what about the work interests you the most?

I am studying part-time at the University of Auckland, doing a PhD on great white shark movements and population monitoring in New Zealand. This research is a collaboration between the university, NIWA and the NZ Department of Conservation. The opportunity to undertake this research came about as a result of the species protection in NZ waters. Most sharks have been tagged at Chatham and Stewart Islands and almost all have migrated to subtropical and tropical habitats during winter (e.g. NSW and Queensland, Norfolk Island, New Caledonia, Fiji and Tonga). I am currently investigating the use of photo-identification to estimate population size and monitor population trends. White sharks are a fantastic animal to photo-ID as every individual is recognisable from its colour pattern and they often return to the same spot year after year.

This journal post was written by Australasian Fishes member, Harry Rosenthal.
Publicado el abril 6, 2018 05:00 MAÑANA por markmcg markmcg | 6 comentarios | Deja un comentario

30 de abril de 2018

A fourth new record for Sydney Harbour!

A huge thank you goes to Kim Dinh who recently added an observation of a 3 cm long juvenile Blackspotted Puffer, Arothron nigropunctatus, photographed in Sydney Harbour. (left image).
The species had not previously been recorded from the Harbour. The Sydney Harbour Fish list, which now contains 595 species. has been updated.
Kim's observation, which was made on the 9th April 2018, was followed up by a second sighting of the same fish 12 days later*. Kim reported that the fish had grown to about 5cm in length.
The Blackspotted Puffer is a tropical species. In Australia, it occurs from northwestern Western Australia, around the tropical north of the country, and on the east coast south to the Shoalhaven River, New South Wales. The species has previously been photographed south of Sydney by Andrew Trevor-Jones (right image), but Kim's observation is the first time it has been documented from within the harbour.
Since Australasian Fishes went online in October 2016, 3 species have been added to the Sydney Harbour List in addition to Kim's recent observation.

*To view Kim's second image, click on the left image above and wait for the observation page to display. Next, click on the second thumbnail image visible under the large image.
Publicado el abril 30, 2018 05:38 MAÑANA por markmcg markmcg | 9 comentarios | Deja un comentario