Abu Dhabi, UAETuesday 12 November 2019

Lots of flying for today's fish supper

Sometimes you will go to the ends of the earth for a great meal. At least, you will if you are anything like the Socotra Comorant.
The UAE has about 38,000 breeding pairs of Socotra Comorants, about a third of the world's total. Picture courtesy Rob Gubiani.
The UAE has about 38,000 breeding pairs of Socotra Comorants, about a third of the world's total. Picture courtesy Rob Gubiani.

Sometimes you will go to the ends of the earth for a great meal. At least, you will if you are anything like the Socotra Comorant.

Scientists have discovered that the seabird, which is a native of the UAE, will travel hundreds of kilometres in a single feeding - and in doing so, they have strengthened the case for a national protection strategy of the country's coastline.

It was previously thought that the Socotra Cormorant fed near nesting sites, says Rob Gubiani, a biologist at UAE University.

"It kind of makes it quite clear to you how important it is to save what we have along the coastline because we don't know where these guys go," says Mr Gubiani.

He and Timothee Cook, an ornithologist from the University of Cape Town, spent last autumn on Siniya island in Umm Al Quwain, one of the birds' main breeding colonies, which is home to an estimated 15,500 breeding pairs. There, in late October and early November, they caught dozens of the cormorants, fitting them with a US$35 GPS tracker that monitored their flight.

It was the first satellite tracking of Phalacrocorax nigrogularis, which is indigenous to the Arabian Gulf, Arabian sea, the Gulf of Oman and Gulf of Aden. One map shows a single bird's flight from Siniya to the man-made archipelago of The World in Dubai. It spent two days over shallow coastlines of Sharjah and Ajman, a day in Ras Al Khaimah and went as far north as the Oman border.

"Down here is The World," explained Mr Gubiani, pointing to a map of the UAE coast. "It hung out there all day." The area around the World is dotted with tight circles around the areas where it landed and fed.

Each looping line on the map - which may represent hundreds of kilometres - is a day's flight, a single feeding session. The birds looped out further each day, maybe following fish up the coast.

But while it is known that the cormorant would have travelled in a large group, it remains unclear whether these individuals represent the norm, or how far they fly on average.

"First time we've done this," says Mr Gubiani. "We don't know where they go. So this is gold.

"We never knew where they went before, we never knew that they went that far south, that far north. Now that we know that they go there, it really strengthens the case for protection of the coastline."

The research is part of a long-term project funded by the National Research Foundation, the Mohammed bin Zayed Species Conservation Fund and in collaboration with the Environment Agency-Abu Dhabi and the Marine Environmental Research Centre.

Next season Dr Cook will return with 50 satellite transmitters to shed light on the birds' movements during the non-breeding season, their feeding habitats in the breeding season, and possible roosting locations. He also hopes to find out whether the cormorants in the Gulf mix with colonies in Oman.

According to Oscar Campbell, the chairman of the Emirates Bird Records Committee, the work so far points to a need for conservation of the cormorants, which are listed as a vulnerable species by the International Union for Conservation of Nature (IUCN).

"The birds are using lots of different areas in the UAE waters," he says. "So to conserve them, obviously, the colony needs to be conserved on Siniya island - but that is going to be useless if there are not healthy fisheries for them as well.

"It is very likely that they move much further than Ras Al Khaimah. For example, if you go to Fujairah on the East Coast you can see several hundreds and there are no colonies anywhere there. The nearest colony is Siniya island.

"These birds will need healthy fisheries and they will need shelter at undisturbed beaches. Just protecting the colony isn't enough."

The biologists found further evidence of the birds' sensitivity to disturbance in their choice of nesting site on Siniya island this season compared with last year. In 2011, the birds nested under planted trees and left the island by January.

But last year, the cormorants arrived later and nested at three smaller satellite colonies around the island that were in full sun.

More experienced birds selected the best habitat first, a traditional nesting site in an area free of trees at the edge of the 15-km long island.

The second colony nested on a sliver of land in the north. The third colony, about 300 metres west, was annihilated by foxes within four weeks.

In 2012-13 the cormorants nested in sequence, from August to May. In February this year, scientists found a fresh colony of about 1,500 breeding pairs.

"We were scratching our heads, wondering what's going on," said Dr Sabir Muzaffar, the UAE University professor who heads the study. "Historically, they have always nested in the place they nested in 2012 [this season]. In 2011 it was different and we're not sure exactly why."

The only way to get an answer, he says, is to keep gathering data for four or five years, in the hope of eventually finding a pattern to the birds' choice of nesting site.

Getting that answer is urgent. The UAE has about 38,000 breeding pairs, about a third of the world's total. But they may be dwindling rapidly - since 2006 at least seven of the UAE's 20 colonies have gone, largely because of oil development and human disturbance.

"There's good reason to think that they are probably now endangered," said Dr Muzaffar. However, he worries that formal, effective protection of the species is "not on the radar".

The shrinking population could have a profound effect on the rest of the region's wildlife. Cormorants are opportunistic feeders who eat the most abundant fish species - if the birds dwindle or vanish, the balance of those populations could become dangerously skewed.

That may already be happening. In 2011-12 season, the scientists found that 90 per cent of all meals eaten by the cormorants consisted of three species of flying fish. But in 2012-13, those fish species were completely absent from the birds' diet.

The reasons are unclear, but it may be connected to the timing of the breeding season - which might be co-ordinated with peaks in certain fish numbers. Discovering whether that is the case could dispel the myth that the cormorants compete directly with fishermen, who do not catch flying fish. Other colonies have been destroyed by egg collectors or because of their smell.

Even if the cormorants survive the pollution, the oil spills and coastal development, there are foxes and feral cats to worry about. It is estimated that just one adult fox can kill about 2,000 cormorants a year.

This season's study will look into the impact of foxes and ticks, breeding success and population numbers. The challenge is to fight the unfounded negative perception of the bird and to do this, years of research are needed.

"People have had a really negative perception of these birds for a long time. Tick bites, djinn powers," said Mr Gubiani. "Basically nothing's known about these guys, there's a real hatred of them. That's the fear, the fear of the unknown."

But for him, he says, "they're actually pretty cool birds. I love 'em."



Updated: September 1, 2013 04:00 AM