Scientists are reading rockfish ear bones
By the OSU News Service
Like tree rings, they can be used to determine age and other data
NEWPORT Scientists at Oregon State University's Hatfield Marine Science Center have found a link between the growth rings of trees and the growth rings from ear bones of long-living rockfish species.
Their findings could provide new information for resource management, and clues about the impact of climate on-shore and at sea.
Study results will be published in the Canadian Journal of Fisheries and Aquatic Sciences.
In trees, growth rings can determine the age of a tree and effects of climate on its growth. Climate induces the same growth patterns in all trees at a site.
Narrow rings indicate drought years, while mild or wet conditions lead to a wider ring.
"Fluctuations in climate over time form a distinct growth pattern, much like a bar code, that can be cross-matched among the trees," said Bryan Black, an assistant OSU professor at the Hatfield Center.
"This pattern matching, or cross-dating' is an extremely powerful tool for precise dating and is the fundamental procedure of any tree-ring study," Black said.
"We've found that the same concept applies to otolith (ear bone) growth increments and, for the first time, we're able to apply that same level of precision to fish."
Just as tree rings reflect precipitation and temperature, rock fish ear bones record variations in ocean temperature and upwelling, among other factors.
The year 1983 showed up as a narrow band in nearly all rockfish ear bones. That coincided with one of the strongest El Nino occurrences of the century, and poor upwelling and poor prey production limited rockfish growth.
By statistically isolating the climate-induced "bar codes," Black precisely dated all growth increments in these fish, and the fish could be precisely aged, as well.
The tie between ocean variability and fish growth is as strong as the relationship between temperature or precipitation and tree growth in many tree ring studies, Black said.
Although the rockfish are small, growing only to 18 inches, they can live as long as 90 years.
Scientists worked primarily with splitnose and canary rockfish for their study, but other long-lived fish with ear bones may also be valuable as environmental indicators. Some bivalves with rings on their shells and deep-sea corals have similar age patterns.
Researchers aim to compare the fish ear bone rings to tree growth rings, and establish a linkage between marine and terrestrial ecosystems.
Already some patterns are apparent. When ocean conditions are warm, the winter is less severe and the growing season for trees in the Cascades starts earlier and lasts longer. Tree rings become wider, not narrower just the opposite signature from the rockfish.
"The inverse connection between tree growth at 5,000 feet in the high Cascades, and rockfish living hundreds of feet below the ocean's surface, is fascinating," Black said.
By the OSU News Service
Like tree rings, they can be used to determine age and other data
NEWPORT Scientists at Oregon State University's Hatfield Marine Science Center have found a link between the growth rings of trees and the growth rings from ear bones of long-living rockfish species.
Their findings could provide new information for resource management, and clues about the impact of climate on-shore and at sea.
Study results will be published in the Canadian Journal of Fisheries and Aquatic Sciences.
In trees, growth rings can determine the age of a tree and effects of climate on its growth. Climate induces the same growth patterns in all trees at a site.
Narrow rings indicate drought years, while mild or wet conditions lead to a wider ring.
"Fluctuations in climate over time form a distinct growth pattern, much like a bar code, that can be cross-matched among the trees," said Bryan Black, an assistant OSU professor at the Hatfield Center.
"This pattern matching, or cross-dating' is an extremely powerful tool for precise dating and is the fundamental procedure of any tree-ring study," Black said.
"We've found that the same concept applies to otolith (ear bone) growth increments and, for the first time, we're able to apply that same level of precision to fish."
Just as tree rings reflect precipitation and temperature, rock fish ear bones record variations in ocean temperature and upwelling, among other factors.
The year 1983 showed up as a narrow band in nearly all rockfish ear bones. That coincided with one of the strongest El Nino occurrences of the century, and poor upwelling and poor prey production limited rockfish growth.
By statistically isolating the climate-induced "bar codes," Black precisely dated all growth increments in these fish, and the fish could be precisely aged, as well.
The tie between ocean variability and fish growth is as strong as the relationship between temperature or precipitation and tree growth in many tree ring studies, Black said.
Although the rockfish are small, growing only to 18 inches, they can live as long as 90 years.
Scientists worked primarily with splitnose and canary rockfish for their study, but other long-lived fish with ear bones may also be valuable as environmental indicators. Some bivalves with rings on their shells and deep-sea corals have similar age patterns.
Researchers aim to compare the fish ear bone rings to tree growth rings, and establish a linkage between marine and terrestrial ecosystems.
Already some patterns are apparent. When ocean conditions are warm, the winter is less severe and the growing season for trees in the Cascades starts earlier and lasts longer. Tree rings become wider, not narrower just the opposite signature from the rockfish.
"The inverse connection between tree growth at 5,000 feet in the high Cascades, and rockfish living hundreds of feet below the ocean's surface, is fascinating," Black said.
