Teetering on the brink - Percy FitzPatrick Institute of African ...

seine languageThe African Penguin Spheniscus demersus isone of seven seabird species confined to theBenguela upwelling region off the coast ofsouthern Africa. Like penguins worldwide, this specieshas broad public appeal, and its accessible breedingcolonies at Boulders Beach and Stony Point contributesignificantly to the tourism value of the WesternCape. But all is not well in penguin land. At the startof the 19th century there were about a million AfricanPenguins on Dassen Island alone; currently there arefewer than 30 000 pairs worldwide.Coupled with the disturbance caused by peoplescraping for guano, the African Penguin’s initialdecrease resulted from egg collecting, with as manyas 600 000 eggs being taken from Dassen IslandAbovePorpoising is a fast but energetically expensive way for AfricanPenguins to travel at sea. Most commuting is done at a more sedatethree to six kilometres an hour, which saves energy but constrainsthe area they can search for food when breeding.oppositeAfrican Penguins can suffer from heat stress ashore, especially whenbreeding in exposed sites. Exceptionally hot days can cause parents todesert their nests, leaving their eggs and chicks exposed to predation.albert froneman (2)each year. But penguin numbers have continued todecrease after these activities ceased. Loss of guanofrom the breeding islands has made it more difficultfor the birds to find suitable nests, thus reducingbreeding success, and oil pollution is an ongoingproblem. But the main reason for the species’ decreasesin recent decades has been a shortage of food. Likemany other predators in the Benguela region, adultAfrican Penguins rely on sardines and anchovies forthe bulk of their diet. As these pelagic schooling fishalso form the basis of a valuable purse-seine fishery,penguins compete with humans for food.Off Namibia, there was a dramatic collapse insardine landings during the early 1970s. Pelagic fishwere replaced by jellyfish and salps, which consumedmost of the eggs and larvae produced by the dwindlingfish populations. This has switched the systemto a new stable state dominated by these gelatinouszooplankton. The bad news for penguins is that jellyfishand salps are a poor substitute for pelagic fishand cannot sustain significant seabird populations.As a result, populations of seabirds breeding at theNamibian guano islands have decreased dramatically.Over the past five decades, African Penguin numbersin Namibia have decreased by more than 90 per cent,from some 50 000 pairs in the 1950s to only 5 000pairs in the 2000s.The southern Benguela off South Africa also saw acrash in sardine landings following over-exploitation inthe 1960s, but much of the slack in the system wastaken up by anchovies. Careful management of the fisheryduring the 1970s and 1980s saw the slow recoveryof sardines, and by the 1990s seabird populations wereincreasing, linked to a few bumper years of anchovyrecruitment. Unfortunately, the good times haven’tlasted. During the past decade, pelagic fish stocks havedwindled off the west coast, where most penguinstraditionally have bred, forcing predators – and thefishery – to travel farther and farther south and east inpursuit of prey. The south-eastward movement of preyis thought to result from a combination of environmentalfactors favouring populations breeding on the southcoast rather than the west coast, coupled with greaterfishing pressure along the west coast, where fleets andprocessing plants are concentrated.A shift in penguin prey isn’t too serious when thebirds are free to follow it. But, while breeding,adult penguins depend on a reliable source of foodfor themselves and their chicks close to the breedingisland, and most African Penguins remain within 20 to30 kilo metres of their breeding islands at this time. Birdsforced to travel further than this spend so long commutingthat they struggle to raise a brood of healthychicks. To make matters worse, adult African Penguinsare creatures of habit and return to breed at the samesite each year. As a result of the lack of food, penguinnumbers off South Africa’s west coast fell from almost40 000 pairs in 2004 to barely 12 000 pairs in 2008.This calamitous decrease has led for calls to upgradethe species from globally Vulnerable to Endangered.The fishing industry faces a similar challenge fromthe shift in fish stocks. Longer commuting distancesbetween fishing areas and processing plants, coupledwith sharp increases in fuel prices, have forced somecompanies to make the costly decision to relocate theirplants to Mossel Bay on the south coast. Sadly, thisoption isn’t open to penguins, as there are no suitablebreeding islands between Dyer Island, just east ofHermanus, and Port Elizabeth. A few pairs have triedto breed along the remote De Hoop coastline, but theyare vulnerable to terrestrial predators.Although climate change might be the ultimatefactor driving the shift in fish populations,competition with purse-seine fisheries aroundbreeding colonies almost certainly exacerbates the situationfor penguins. As a result, Marine and CoastalManagement, the government agency responsible formanaging South Africa’s fisheries and marine resources,has devised an ambitious plan to try to improve conditionsfor breeding penguins. With the cooperation ofthe purse-seine industry, fishing has been stopped foran initial two-year period within 20 kilometres of twokey breeding sites: Dassen Island on the west coast andSt Croix Island off Port Elizabeth. Teams of scientistswill monitor whether this improves the lot of penguinsbreeding there compared with birds breeding on nearbyislands that have not been afforded any protection,namely Robben and Bird islands.Lorien Pichegru, a post-doctoral fellow at UCT’sFitzPatrick Institute, has been tasked with monitoringthe performance of penguins breeding at St Croixand Bird islands in Nelson Mandela Bay. Typically,fishing pressure is far greater around St Croix, whichlies close to Port Elizabeth. Perhaps as a result of this,African Penguins breeding on St Croix in 2008 hadto work much harder than those breeding on BirdIsland to find food for their chicks, travelling on averagealmost twice as far. From the start of 2009, fishinghas ceased within 20 kilometres of St Croix andwithin a five-kilometre radius of the Riy Bank, a keyarea for fish south of St Croix.Pichegru and a team of students will test what effectthis has on the islands’ penguins over the next twoyears. She will use GPS-loggers to track foraging birdsand thus estimate their foraging effort, and couplethese data with more traditional measures suchas population size, diet sampling, breedingsuccess and chick growth rates. Offthe west coast, CapeNature, Marine andCoastal Management and Robben IslandMuseum (together with partners) arerunning similar programmes on Dassenand Robben islands, while Lauren Wallerfrom the Dyer Island Conservation Trust iskeeping a close eye on the performanceof penguins at Dyer Island.Sceptics might argue that anchoviesand sardines are highly mobile,and that closing areas to fishingimmediately adjacent to breedingislands will be of little benefit topenguins, especially if the fishingeffort that traditionally occurredin these areas is simply displaceda few kilometres away. It mayrequire a marked reductionin catches off the westcoast or even a cut in thetotal fishing quota to makea significant difference forpenguins and other predators.However, such interventionswould have seriouseconomic implications andthus face stiff oppositionfrom the fishing industry. Wedon’t know whether smallerno-take areas will be effectiveuntil they are tested. Ifthey do work, the benefitswill extend beyond AfricanPenguins to the many otherpredators that depend onpelagic fish for food. 44 african penguins africa – birds & birdingjune/july 2009african penguins 45