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Posted by Lauren Smith on

Call of the Blue

Call of the Blue

On the 19th of November i headed down to the Natural History Museum in London, i was attending a book launch party and would be doing a Q&A session on sharks whilst there. The book by Philip Hamilton is entitled “Call of the Blue” and tells the story of positive, focused people who are working to save our oceans. Featuring incredible images captured by Philip over a 5 year period, with chapters outlining the efforts by individuals and communities to inspire and drive change.

I was absolutely honoured to be a part of this, having been contacted around 18 months ago by Tom Hooper to give an interview about my work with sharks, excerpts of which were to be featured in the book. The launch was fantastic, representatives from all sectors were present, including CEO’s from huge companies, marine charities, activists and researchers like myself. All were there to understand more about our marine environment and the threats it currently faces.

In the afternoon prior to the launch party, the head curator of the fisheries department James Maclaine, was kind enough to indulge my curiosity and gave me a behind the scenes tour of the preserved elasmobranch specimens that were kept in the archives. This was absolutely fascinating and a real treat to see the scale of the collections they had, highlights included a Greenland Shark (Somniosus microcephalis), that had washed up on the UK coastline. This species is in my opinion one of the most extraordinary sharks out there, recent research using radio carbon dating techniques have been used on the eye tissue of these sharks. Results revealed that of the sharks sampled, age ranges varied with the minimum age being AT LEAST 272 YEARS OLD! The 2 largest sharks in the study were estimated to be between 335-392 years old! 

Having recently collected a number of eggcases around the Scottish coastline, i was particularly looking forward to seeing what species of eggcases were in the NHM collection. I was not disappointed! I was delighted (and a little concerned that i would drop it) when James handed me a Chimaera eggcase collected in 1904.

Equally fascinating was the enormous Great White Shark jaw, it was donated in the 1800’s to the museum and since then there has been an enormous amount of speculation as to the size of the shark that this jaw belonged to. Some scientists believe that the shark would have been around 8m!!! The stuff dreams are made of – well my dreams at any rate!

 

Posted by Lauren Smith on

Beach cleans & shark guts… it’s all rubbish

Beach cleans & shark guts… it’s all rubbish

Alongside my work as a shark biologist, I am a volunteer for the charity Surfers Against Sewage. As part of this role I organise and participate in numerous beach cleans along the U.K. coastline, more often than not the bulk of rubbish that we remove during these cleans are plastic items. Now assuming you haven’t been marooned in outer space in recent years, you will be well aware of the mounting plastic crisis and the fact that particles of plastic can be found in just about everything, from the air we breathe to the water and food we consume.

The ingestion of plastic debris by marine animals has been documented across a variety of species

including; marine mammals, sea birds, sea turtles and some fish species. However fewer reports have described ingestion by sharks, and so for me it was a logical step to investigate whether a small shark species, commonly landed in the U.K. contained plastics. The small spotted catshark, more often referred to as the lesser spotted dogfish (cats… dogs… for the record they are catsharks, dogfish refer to another type of shark species), are often caught in bottom trawls and line gear, although technically bycatch the larger individuals are retained for human consumption, whilst the smaller ones are used for fish meal or pot bait.

I contacted a local fish merchant based in Fraserburgh on the Moray Firth Scotland, they kindly donated 20 sharks that had been captured in the North Sea and I set about investigating the contents of their gastrointestinal tracts, a polite way of saying I dug about and scrutinised their guts, recording any identifiable objects both natural and artificial.

Of the 20 sharks i sampled, all showed evidence of predation on natural prey sources prior to being trawl captured. Remains of hermit crab carapaces, squid beaks and fish bones were found. In addition to this 3 individuals were also found to contain plastic debris within their stomachs, one is a microplastic (defined as any particle less than 5mm) believed to be a micro-bead, the other two are macroplastics (>20mm); one is thought to be a broken and eroded tag and the other is composed of three fibres most likely originating as synthetic rope.

S. canicula are known to be opportunistic feeders that predate on a wide range of fauna, including shellfish, crabs, squid and small fish. It is unclear as to whether the plastics found within the stomachs of S. canicula had been ingested directly from the water column itself, or whether these items had been previously consumed by their prey. It remains unknown for now as to whether the ingestion of these plastics will negatively impact the individual sharks, however recent studies show that the potential effects on marine species from the uptake of microplastics include; reduced survival, inability to predate effectively, oxidative status and uptake of persistent organic pollutants. Current research is now investigating the effects of biomagnification and bioaccumulation of plastics and associated chemicals throughout freshwater and marine ecosystems.

S. canicula are considered an abundant shark species with an IUCN (International Union for the Conservation Nature) Red List status of “least concern”and yet with increasing environmental threats such as plastic ingestion, combined with the overfishing of other species, resulting in these sharks being used as market substitutes, it remains to be seen for how long this status will hold true.

My study reports the first evidence of plastic debris in the stomach of S. canicula, and yet I wasn’t surprised, heck I expected to find some evidence of plastics I just wasn’t sure how much. If this isn’t depressing and a sign of our times I don’t know what is. But with recent reports detailing that an estimated 75% of all the litter in our oceans is plastic, and with around 5 million tonnes of plastic waste entering the seas annually (Thompson, 2017), its no wonder I am not surprised only saddened that I am finding plastic in the guts of sharks.

What’s the link between beach cleans and shark guts?

Alongside my work as a shark biologist, I am a volunteer for the charity Surfers Against Sewage. As part of this role I organise and participate in numerous beach cleans along the U.K. coastline, more often than not the bulk of rubbish that we remove during these cleans are plastic items. Now assuming you haven’t been marooned in outer space in recent years, you will be well aware of the mounting plastic crisis and the fact that particles of plastic can be found in just about everything, from the air we breathe to the water and food we consume.

The ingestion of plastic debris by marine animals has been documented across a variety of species

including; marine mammals, sea birds, sea turtles and some fish species. However fewer reports have described ingestion by sharks, and so for me it was a logical step to investigate whether a small shark species, commonly landed in the U.K. contained plastics. The small spotted catshark, more often referred to as the lesser spotted dogfish (cats… dogs… for the record they are catsharks, dogfish refer to another type of shark species), are often caught in bottom trawls and line gear, although technically bycatch the larger individuals are retained for human consumption, whilst the smaller ones are used for fish meal or pot bait.

I contacted a local fish merchant based in Fraserburgh on the Moray Firth Scotland, they kindly donated 20 sharks that had been captured in the North Sea and I set about investigating the contents of their gastrointestinal tracts, a polite way of saying I dug about and scrutinised their guts, recording any identifiable objects both natural and artificial.

Of the 20 sharks i sampled, all showed evidence of predation on natural prey sources

prior to being trawl captured. Remains of hermit crab carapaces, squid beaks and fish bones were found. In addition to this 3 individuals were also found to contain plastic debris within their stomachs, one is a microplastic (defined as any particle less than 5mm) believed to be a micro-bead, the other two are macroplastics (>20mm); one is thought to be a broken and eroded tag and the other is composed of three fibres most likely originating as synthetic rope.

S. canicula are known to be opportunistic feeders that predate on a wide range of fauna, including shellfish, crabs, squid and small fish. It is unclear as to whether the plastics found within the stomachs of S. canicula had been ingested directly from the water column itself, or whether these items had been previously consumed by their prey. It remains unknown for now as to whether the ingestion of these plastics will negatively impact the individual sharks, however recent studies show that the potential effects on marine species from the uptake of microplastics include; reduced survival, inability to predate effectively, oxidative status and uptake of persistent organic pollutants. Current research is now investigating the effects of biomagnification and bioaccumulation of plastics and associated chemicals throughout freshwater and marine ecosystems.

S. canicula are considered an abundant shark species with an IUCN (International Union for the Conservation Nature) Red List status of “least concern”and yet with increasing environmental threats such as plastic ingestion, combined with the overfishing of other species, resulting in these sharks being used as market substitutes, it remains to be seen for how long this status will hold true.

My study reports the first evidence of plastic debris in the stomach of S. canicula, and yet I wasn’t surprised, heck I expected to find some evidence of plastics I just wasn’t sure how much. If this isn’t depressing and a sign of our times I don’t know what is. But with recent reports detailing that an estimated 75% of all the litter in our oceans is plastic, and with around 5 million tonnes of plastic waste entering the seas annually (Thompson, 2017), its no wonder I am not surprised only saddened that I am finding plastic in the guts of sharks.

Having visited 25 beaches in the past 6 months, along the U.K., French, Spanish & Portuguese coastlines and having found plastics on every single one of those beaches the consequences of our plastic mania will be felt far into the future. However the current wave of awareness about plastic pollution amongst the general public is encouraging, the more information and education that is provided via environmental charities such as Surfers Against Sewage and through TV Shows like Blue Planet 2 as well as on social media, will create positive change by allowing people not only to make more informed choices but also to lobby and campaign to bring about change, that is so desperately required.

References

Avio, C.J., Gorbi, S., Regoli, F., 2017. Plastics and microplastics in the oceans: From emerging

pollutants to emerged threats. Marine environmental research. 1-10.

Colmenero, A.I., Barria, C., Broglio, E., Garcia-Barcelona, S., 2017. Plastic debris straps on threatened blue shark Prionace glauca. Marine Pollution Bulletin. 115, 436-438.

Derraik, J.G.B., 2002. The pollution of the marine environment by plastic debris: a review. Marine

Pollution Bulletin. 44 (9), 842-852.

Mallory, M.L., 2008. Marine plastic debris in northern fulmars from the Canadian high Arctic. Marine Pollution Bulletin. 56, 1501-1504.

Putnam, A.R., Clune, A., Buksa, B., Hammer, C., VanBrockin, H., 2017. Microplastic biomagnification in Invertebrates, Fish and Cormorants in Lake Champlain. Centre for Earth and Environmental

Science. 37.

Smith, L.E., 2018. Plastic ingestion by Scyliorhinus canicula trawl captured in the North Sea. Marine Pollution Bulletin. 130. 6-7.

Thompson, R., 2017. A journey on plastic seas. Nature. 547, 278-279.

Posted by Lauren Smith on

Hammer-time!

Hammer-time!

What does Hannibal Lecter, Ernest Hemmingway and I have in common? A taste for fava beans and a nice Chianti? (Chianti – yes), renowned literary skill? (pah! If only!). The answer is in fact the islands of Bimini, Bahamas situated 50 miles off the coast of Florida, North & South Bimini are the smallest habitable islands in the Bahamas with a total area of 9-square-miles and just over 2000 inhabitants.

bimini

Hemmingway began visiting the islands in 1935 and spent time fishing and writing, whilst angling he garnered knowledge which contributed to the creation of Old Man and the Sea and Islands in the Stream. An Atlantic Blue Marlin caught off Bimini weighing in at 500lbs was allegedly the inspiration behind these novels.

The final scene of Silence of the Lambs see’s Dr Lecter calling Agent Starling from a payphone on a tropical island, that island being North Bimini.

bimini customs

So what is it about Bimini that resulted in my visit, or to be more precise – my return visit? I had first gone to Bimini when I was conducting research for my PhD in 2006, I was staying at the Bimini Biological field Station (Shark-Lab) founded by “Doc” Gruber and was tracking juvenile Lemon Sharks and investigating their depth utilization.

Bimini is a well known Lemon Shark nursery area first recorded by Doc in the 1980’s, however in addition to the Lemon Sharks the Bimini Islands are a marine biologists and even more so a shark biologists dream, in shallow, clear waters you can see Nurse, Blacknose, Blacktip, Caribbean Reef, Tiger & Bull Sharks as well as Rays, Sawfish and the reason for my trip this time, the Great Hammerhead (Sphyrna mokarran).

hammer 2

There has been talk of Great Hammerheads visiting the waters around Bimini from January through to March for decades, and long is the legend of South Bimini Islands “Harbour Master” a huge Hammerhead patrolling the docks for fishermen’s scraps. However it has only been the last few years that the area has emerged into the main stream and has become recognised as the place to dive with aggregations of Great Hammerheads.

hammer 3

I was there with Dr Craig O’Connell founder of O’Seas Conservation foundation and his team (Guido Leurs founder of Oceaware, Marcella Uchoa and Rachel Jacobson), I had first met Craig on my initial visit to Bimini and having kept in touch and collaborated on a research paper together it was a fitting place to catch up in person! We has rented a boat and were observing and photographing animals in situ by freediving and SCUBA diving.

2 hammer

Put simply, my dives with the Hammerheads blew me away!! Once the bait had gone in the water we were inundated with nurse sharks typically after only a couple of minutes, on average we only had to wait around 20 minutes until the unmistakable outline and approach of the Hammers were spotted from the boat, a speedy kitting up and grabbing of camera equipment ensued (with a quick nod to the O’ring gods) and we descended down to the white sand with depths around 6m. Seeing these animals up close in the water was incredible, I certainly don’t possess the vocabulary or the literary skill to do them justice, they are truly humbling and awesome.

socks

On each dive Hammers exhibited different behaviours and swimming patterns which allowed for some fantastic photography opportunities , unlike the more classic shark body shape the angles and form of the Great Hammerheads combined with the sunlight filtering through the water and the approach of the sharks created the potential for yet another different and interesting shot, the opportunities were endless!

hammer 4

Sphyrna mokarran is the largest species of hammerhead shark, capable of attaining a total length of just over 6m (20ft) with 4m being a more usual maximum length. They are unmistakable with the straightness of the front margin of their head combined with their enormous sickle shaped first dorsal fin, they are a coastal pelagic and semi-oceanic species, considered to be an opportunistic predator feeding on a variety of prey including; stingrays and other batoids, small shark species, groupers, toadfish, jacks, crabs and squid etc. Males reach maturity around 2.5m and females around 3m, females breed every 2 years and have an 11 month gestation period (they are viviparous – pups nourished with a yolk sac placenta), litter size ranges from 6-42.

S. mokarran is classified as endangered by the IUCN Red List with a declining population trend, animals are taken as by-catch and as a target species in longline, fixed bottom net, hook & line, and pelagic and bottom trawl fisheries. Their fins are highly prized for shark-fin soup. These fishing pressures coupled with the Great hammerheads size at maturity and low fecundity make it extremely vulnerable, global population declines range from 79-90% in the last 25 years. In 2014 S. mokarran was listed on CITES Appendix II, which includes a list of species that are not necessarily now threatened with extinction but that may become so unless trade is closely controlled. International trade in specimens of Appendix II species may be authorized by the granting of an export permit or re-export certificate. No import permit is necessary for these species under CITES (although a permit is needed in some countries that have taken stricter measures than CITES requires). Permits or certificates should only be granted if the relevant authorities are satisfied that certain conditions are met, above all that trade will not be detrimental to the survival of the species in the wild.

On the subject of protection I worry about the future of Bimini and its marine wildlife, since I first visited the island 9 years a lot has changed. A Malaysian consortium (work originally began by “Bimini Bay Resort” but is now “Resorts World Bimini”) was granted approval to build a resort, casino, marina complex designed to attract 500,000 tourists a year, as a result mangrove habitats have been destroyed (essential shark nursery areas) and dredging of channels for cruise ships has taken place with the resulting repercussions on the coral reefs and critical habitats for other species such as lobster, grouper, and conch not to mention the natural storm protection for the island itself.

Bimini is a place with the power to turn dreams into a reality, my sincere hope is that people in positions of power will recognise the true beauty of Bimini and conserve it so that these Islands will never be referred to in the past tense, as a paradise lost….

 References and Further Reading;

http://www.iucnredlist.org/

http://www.bahamas4u.com/bimini.html

http://www.telegraph.co.uk/news/worldnews/centralamericaandthecaribbean/bahamas/10947445/Islands-In-The-Stream-The-battle-for-the-soul-of-Bimini.html

https://www.youtube.com/watch?v=Su5WKbaqbDA