Endangered African penguins benefit rapidly when fishing is banned from even relatively small areas around their colonies, a new study has found.
The African penguin's population declined by 90 percent in the 20th century; between 2004 and 2008, its numbers plunged by half to 26,000, the lowest yet recorded. The decline is the result of a combination of changing environmental conditions, including warming waters, causing the anchovies and sardines on which they prey to shift farther away from the coast, and the presence of purse-seine fisheries in coastal waters.
In January 2009, South African authorities closed a 12.5 mile (20 kilometers) radius area to fishing around St. Croix Island in Algoa Bay, while leaving the waters around Bird Island, 38 miles (60 kilometers) away in the same bay, open to fishing. Researchers attached miniature GPS recorders to the backs of birds from both islands to study what effects the contrasting conditions had on their foraging behavior.
In 2008, before the area was closed to fishing, three-quarters of the dives the St. Croix penguins made for food were more than 12.5 miles (20 kilometers) from their colony; often, the birds were obliged to travel up to 100 miles (160 kilometers) during the course of two days in their search for food. Within three months of the area being closed to fishing in 2009, 70 percent of dives were within the protected marine area and the time the penguins devoted to searching for food decreased by 30 percent, which reduced their daily energy expenditure by 40 percent. In contrast, the area within which the Bird Island penguins searched for food remained the same both years, with the penguins even expending more energy searching for food in 2009.
The researchers conclude that the study underlines the impact of industrial fishing on feeding conditions for African penguins, and the significant and rapid benefits of establishing marine protected areas.
Source: Pichegru, L., et al. 2010. Marine no-take zone rapidly benefits endangered penguin. Biology Letters, doi: 10.1098/rsbl.2009.0913. Full text available online:
http://rsbl.royalsocietypublishing.org/content/early/2010/02/04/rsbl.2009.0913.full
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