In the wake of National Marine month in October, Kamcilla Pillay examines the role marine birds play in maintaining the fragile balance of ecosystems and the challenges testing the survival of those on KwaZulu-Natal’s coast
Marine environments are often synonymous with fish and other water-dwelling animals, with little focus placed on other species, without which most systems would be stymied.
KwaZulu-Natal is home to several pelagic seabirds (those species that live along the coast), with some of them being vulnerable to population declines because of fishing practices.
The birds in particular danger, says bird conservation group – Birdlife SA’s Albatross Task Force – are the many species of albatross which call the province home.
“Albatrosses have unique life history traits which make them vulnerable to population declines, even if a small number of species are being killed. Albatrosses are slow-breeding, being reproductively mature after five and 10 years, depending on the species. They only produce one egg a year (or every two years). They can live (longer than) 60 years,” said the organisation in response to Daily News enquiries.
While not endemic to the province, albatrosses occur in all but one of the world’s oceans (the North Atlantic), and 17 of the 21 albatross species are restricted to the Southern Ocean.
Globally, every year, the organisation said, at least 300 000 seabirds, 100 000 of which are albatrosses, are accidentally killed by fishing operations.
“That amounts to more than 40 birds every hour of every day in the year. In South African waters, estimates of annual mortalities ranged in the tens of thousands, prior to the onset of efforts to remedy the problem in the late 1990s.”
They explained that the main cause for species being assigned to vulnerable, endangered or near threatened categories was that their populations were declining.
“This is due to threats from fishing, including trawling (as a result of cable strikes and drowning in nets) and long lining (where birds went for the squid (bait) on the hooks, got hooked and drowned),” said the organisation.
Other reasons included the presence of invasive species on islands where seabirds bred or were used for ground nesting (or burrowing) and were therefore vulnerable to predation from alien species, and the ingestion of plastics and other pollution while foraging for food.
BirdLife South Africa works closely with the fishing industry to try to alleviate some of the losses.
“Instructors go to sea to monitor seabird by-catch levels. The following measures are encouraged to be adopted by the long line fishing industry: bird scaring lines (both trawl and long line industry); line-weighting (long line, adding weights to the lines allows the lines to sink quickly); and night-setting (this is encouraged, as fewer birds are active at night, thus reducing potential interactions with fishing gear.”
The organisation said that raising public awareness was the key.
“Seabirds are unique and highly charismatic species that have interesting life history traits. They are worth protecting.”
One of the key areas of focus was on the reduction in pollution on the part of beach users.
“Over 70 percent of the pollution in the ocean stems from the land. Rubbish not properly disposed of gets blown into storm drains, rivers, and ultimately ends up in the ocean.”
The organisation also encourages people to make sustainable seafood choices, by opting for fish with the Marine Stewardship Council (MSC) label.
Focusing on Capricorn Fisheries in the Western Cape, leader of the task force Bronwyn Maree said in a research paper this year – titled Significant reductions in mortality of threatened seabirds in a South African trawl fishery – co-authored by several other researchers, that it was estimated in 2004, 9 300 birds had been killed, of which 7 200 were albatrosses.
Bird scaring lines (BSLs) were also used to reduce bird mortalities.
A BSL, as explained in the paper, was flown behind vessels over the area where the birds were most likely to become entangled (alongside the cables) and had brightly coloured streamers attached to a mainline which flapped around and deterred the birds from the danger area.
“From 64 trips and 690 hours of observation, 41 seabirds were confirmed killed due to cable collisions, of which 22 percent were albatrosses. Our data showed that the majority of interactions occurred when vessels were discarding unwanted fishery waste.”
The paper said that comparing rates between the two time periods (between 2004 and 2005 and between 2006 and 2010) showed that through the use of BSLs, there was a 73-95 percent lower mortality rate (based on the data from winter when offal was discarded).
“This equates to an estimated total mortality in this fishery (in 2010) of 990 birds, including 83 albatross. This reflects a 99 percent reduction in albatross deaths, which can mainly be attributed to the use and effectiveness of BSLs.”
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Extinction, slaughter stalks
* Once albatross chicks have fledged, they do not return to land for many years. In the case of “great” albatrosses this may be up to five years, but they may not start breeding until they are up to 10 years old.
* Wandering and royal (“great”) albatrosses have the largest wingspans of any bird in the world, reaching up to 3.5m.
* Albatrosses are among the largest flying birds, weighing up to 10kg.
* The long, narrow wings of albatrosses enable them to glide for thousands of kilometres on wind currents without flapping their wings.
* Simply by angling their wings and their flight path, albatrosses can use the variation in air speed and direction near the waves to soar over the oceans. This phenomenon is called dynamic soaring.
* The wandering albatross flies up to 10 000km to find food for its chick.
* A grey-headed albatross from South Georgia has been recorded circumnavigating the globe in a mere 46 days.
* Nineteen of the 21 species of albatross are globally threatened with extinction.
* Albatrosses are being needlessly slaughtered by long-line fishing vessels because the birds are attracted to the bait, get hooked, dragged under and drowned.
* Long lines kill more than 100 000 albatrosses and 200 000 other seabirds every year.
* Albatrosses are dying at a rate of around one every five minutes.
* The ancestors of albatrosses evolved 50 million years ago, but it has taken only three decades of long-line fishing for many albatross populations to start disappearing.
Practical solutions
* Fishermen can adopt simple and cost-effective measures on their boats to keep albatrosses away from the baited hooks, using dyed bait, or bait that has been dyed blue – making it harder for birds to see it in the water.
* They can also set fishing lines only at night because most albatrosses feed by day.
* Fishermen can also weight fishing lines so that the baited hooks sink more quickly.
Source: www.savethealbatross.net
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Cause for concern: conservation status of KZN seabird species
Albatrosses
Shy Albatross: near threatened.
Indian Yellow-nosed Albatross: endangered.
Black-browed Albatross: near threatened.
Wandering Albatross: rare on KZN, vulnerable.
Grey-headed Albatross: very rare, endangered.
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Petrels
White-chinned Petrel: vulnerable.
Pintado Petrel: least concern.
Great-winged Petrel: least concern.
Southern Giant Petrel: least concern.
Barau’s Petrel: rare, endangered.
Northern Giant Petrel: least concern (provincial rarity).
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Storm-petrels
Wilson’s Storm-petrel: least concern.
European Storm-petrel: least concern.
Black-bellied storm-petrel: least concern.
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Gannets
Cape Gannet: vulnerable.
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Shearwaters
Flesh-footed Shearwater: least concern.
Sooty Shearwater: endangered.
Great Shearwater: least concern.
Cory’s Shearwater: least concern.
Soft-plumaged Petrel: least concern.
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Other seabird species:
Swift Tern, Common Tern, Arctic Tern, Antarctic Tern, Sandwich Tern, Little Tern, Sooty Tern, Kelp gulls, Antarctic Prion.
* Source: Birdlife South Africa