A new study has been proclaimed a classic in its own time and could be the basis of a new Golden Rule for bird ecology. The new study discovered that ensuring that fish stocks remain above a third of the highest previously recorded levels then bird species do well, once levels of fish drop then the birds do badly.
The study was one of the biggest of its type with international scientists contributing to the work. The study showed that once fish stock levels start to fall below a certain level then the sea birds also start to suffer. The critical level at which the birds start to suffer seems to be when fish stocks drop below a third of the maximum previously recorded levels. This critical level appears to hold true wherever in the world the sea birds live. [pullquote]This suggests that we have found an important benchmark that could be used as a guide to limit the amount of fish taken from the sea in order to maintain seabird populations in the long term.[/pullquote]
Keep a third for the birds rule appears wide spread.
The study looked at bird populations and fish stock levels in a wide range of locations from the Arctic to the Antarctic. Whether the birds depended on fish from the Atlantic or Pacific the same critical levels came into play.
This new study could open up a greater understanding of maximum sustainable yields on fisheries and help conservationists to better understand the needs of our most endangered sea birds.
The researchers took a look at 14 different bird species including puffins, penguins and gannets. They looked for how well the species did in breeding when compared to the availability of their main food species such as herring, sardines and krill. The researchers looked at breeding patterns covering between 15 and 47 years depending on species. In total the study looked at a total of 438 years of bird observations.
New rule could be essential of fisheries management and sea bird conservation.
Getting a better understanding of the fish and the sea birds is essential as humans start to fish for ever smaller species of fish – coming into direct competition with many sea bird species.
“This study provides critical information to resource managers in Alaska and elsewhere in the US to ensure the long term sustainability of these species and to the societal and economic benefits they provide,” said Dr. John Piatt of the USGS Alaska Science Center, a contributor to the study.
‘As we fish down the food chain’ to harvest smaller species for fish meal, we expect to see greater impacts to seabirds,” noted USGS director Marcia McNutt, “It is truly astounding that so many long-term land-sea time series from around the globe could be simultaneously assembled for the same purpose, and that they all support the same scientific conclusion. This paper will be an instant classic.”
“We were amazed by the consistency of the relationship around the globe. This suggests that we have found an important benchmark that could be used as a guide to limit the amount of fish taken from the sea in order to maintain seabird populations in the long term,” said the leader of the team, Dr. Philippe Cury of the French Research Institute for Development.
Dr. Ian Boyd of the Scottish Ocean Institute, University of St Andrews, who co-led the study said, “When combined with the effects of climate change, we need to develop better methods of setting the limits of exploitation of important marine species. This means being able to establish general guidelines that, if exceeded, will cause changes to other important components in the ecosystems. Seabirds are some of the best and most easily measured indicators we have of the health of these ecosystems and it seems sensible to use them in this context.”
The authors acknowledge that there’s still work needs to be done to confirm the study and its findings in other parts of the world but so far results look promising for fisheries policy makers and conservationists. There may finally be some concrete figures that can be used in marine policy formation that can be used to help conserve sea bird numbers.