Doc mortgaged his home and borrowed US$30,000 from his elder brother Herbert. The plan was to raise funds by teaching biology courses at the lab when it was up and running. There was already a building on North Bimini that had previously been used as a research station – the Lerner Marine Laboratory – and had closed in 1975. Doc briefly considered it but the rent and upkeep would have been prohibitively expensive – perhaps US$1,000,000 a year – and students and academia would not have mixed with the bars and drug culture of North Bimini at that time. He wanted something lean, the barest minimum of what was required, so that every last cent could go into the research.

The next potential building Doc considered almost turned out to be a disaster: a con artist (who had absconded from justice in the United States and was soon to be escorted back by the CIA) was posing as a real estate agent on Bimini and offered to sell Doc a property he did not in fact own. Luckily, the ruse was discovered just in time.

There was another candidate building Doc knew of in a quiet part of South Bimini: a modest timber structure that was nothing more than a double-wide trailer. It had been used by drug-smuggling Colombians before they were kicked off the island and had thereafter been equipped as a barracks for the Bahamian police, though they never used it. It was now owned by an attorney and friend of Doc’s called Pat O’Neal, who offered to lease it to Doc on nothing more than a handshake. From 1990 to the day before Doc bought the lab in 2013, no paperwork was signed.

At the start everyone thought the project mad and doomed to failure: nothing succeeds on these tatty, sleepy islands – dive shops struggle and fold, hotels limp on mostly empty. Doc’s determination only increased. Six months of back-breaking work were required to turn the building into the Bimini Biological Field Station, most of the equipment being brought across the Gulf Stream by boat.

Years before, when Doc had been a post-doctoral researcher studying under the Nobel Laureate Professor Konrad Lorenz at the Max Planck Institute in Seewiesen, Germany, animals were considered to be nothing more than machines. They did not perceive, they merely detected. Nowadays things have changed and a central subject of the field station’s research is behaviour, including such topics as personality, learning, social behaviour and cognition.

There is another ambitious shift in the Shark Lab’s orientation: to include studies of all the major shark fauna around the islands. Tiger sharks are now most often caught on long-lines (the lemon sharks being too crafty to be regularly re-caught) and the question arises whether there is a tiger shark nursery somewhere on the banks surrounding Bimini. (Just how clever the lemon sharks are is hinted at by the fact that those fitted with transmitters all left the North Sound when a hurricane approached, returning after it had passed by.) Perhaps most exciting of all is the new work on the magnificent great hammerheads that arrive off South Bimini in the winter months. They are being tagged and tracked, and satellite telemetry is planned.

As a University of Miami professor, Doc was required to do committee work and this responsibility was covered by the fact that he was a councillor (for 16 years) of the Bahamas National Trust. He resigned from the trust in protest at the damage done to the inshore ecology of Bimini by the construction of the Bimini Bay Resort. And however myopic and disgraceful that destruction – approved and facilitated by the politicians of a nation that is a contracting party to the international protection of wetlands termed the RAMSAR Convention – it has resulted in the Shark Lab’s researchers having the unhappy opportunity to do before-and-after studies of the Bimini sharks and their nurseries to quantify the impact of the devastation.

If the above sketch gives an idea of the range and variety of the research coming out of the Bimini Biological Field Station, it is only half the story. Doc in fact had three founding principles when he established the Shark Lab. The research – to increase what is known about cartilaginous fishes – always comes first, as anyone who does not pull their weight rapidly discovers. The second core principle is to train and educate the next generation of biologists in the hard-won research techniques perfected at the lab so that they can go on to launch their own careers. Thus the field station’s principal investigators are doctoral candidates whose research proposals have been approved by Doc and the lab’s director and senior scientist Dr Tristan Guttridge. Uniquely, if the doctoral candidates cannot raise funds for their work, the lab is able to support them. As well as being housed and fed for the three years their doctorates are expected to take, all successful candidates naturally have access to the lab’s equipment, volunteers and staff.

Another dimension of the lab’s work is its outreach. It takes Bahamian students with fellowships as well as students from Bahamas Marine EcoCentre, an NGO. Bimini children are regular visitors and the lab staff give lectures to the public as well as doing beach clean-ups. Previously, before the 9/11 attacks slammed the door shut on funds derived from Florida tourism, the Bimini Biological Field Station used to take children from deprived backgrounds for several days. As Doc explains: ‘Here comes a black kid from the ghetto who doesn’t know the Bahamas, has no idea that it’s a black nation. And everyone is black. And then the kid goes into a little laboratory full of white people where the kid is treated like a prince or princess. And we’re fawning all over them because they’re our little angels. That’s a life-changing experience.’

Until 2012 Doc and his wife Marie ran the Shark Lab as a private company; now it is a 501 (c)(3) non-profit organisation, Bimini Biological Field Station Foundation. This gives it much better access to grant money. The property has been bought; the Shark Lab is incorporated in the Bahamas.

What does the future hold for the lab? Every piece of research opens the door on further questions and every year the technology advances, allowing more questions to be answered – so Doc admits he does not know. But if there is one thing the fearless Dr Samuel Gruber fears it is hurricanes. In 1992 he had to evacuate the Shark Lab as Hurricane Andrew approached, having rapidly transformed into a Category 5 hurricane (the highest category). He crammed everyone into his home in South Miami. A devastated Doc was then informed by cell phone by someone on Bimini that the Shark Lab had been knocked off its foundations and was floating in the bay. Two years of back-breaking effort and financial investment had been destroyed. Doc gloomily bought supplies, drove up to Fort Lauderdale airport and flew over to Bimini. Sure enough, he could see a house in the water from the aircraft – but then he realised it was not the Shark Lab. In fact, when he reached the lab, an ecstatic Doc quickly established that the storm damage was minor. The field station was up and running again in a matter of days.

So Doc’s burning ambition is somehow to find the funds to rebuild the Bimini Biological Field Station and make it hurricane-proof, and to raise it above the reach of storm and tidal surge so that the research, the Shark Lab’s unique research, long continues.