NEAH BAY, Wash. - Using a technique known to only a handful of scientists on the West Coast, Makah tribal research scientists are able to pinpoint streams of origin for salmon, halibut and other fish stocks - by analyzing ear bones.
The advanced research technique is providing other much needed information about halibut, salmon, black cod and other fish stocks vital to the tribe.
Makah research fisheries scientist Youngwen Gao identifies fish by analyzing the stable carbon and oxygen ratios found in the fish's ear bone or otolith. The ear bones have annual, seasonal and even daily growth rings. Just like trees, the rings have been used to successfully gage the age of fish, but Gao is able to use the bones to tell him much more.
"When I analyze the carbon, I'm analyzing the food that a fish has eaten," Gao says. "When I'm analyzing the oxygen, I'm getting information about the water."
The reason this is important is because each body of water has a unique oxygen content. In the case of salmon, Gao is able to match fish caught in the ocean with their home streams by analyzing the oxygen content found in the fish's ear bones and coordinating it to water samples taken from local streams.
Gao is also able to discern fluctuations in ocean temperature by "reading" the patterns found in the ear bones. This technique gives Makah scientists important clues about ocean conditions that affect fish survival.
Tribal fisheries manager Russ Svec says the research implemented by Gao and others on the Makah fisheries team is the result of a decision the tribe made 10 years ago to commit its fisheries program to focusing on research projects in its usual and accustomed fishing territories.
"Research is critical when talking about treaty fishing rights and protection of future stocks," Svec says. "We are very fortunate to have Youngwen as a team member for the Makah tribes and its fisheries program."
In his work with halibut, Gao determines where juvenile halibut found near Neah Bay originate. Sourcing halibut is of vital concern to the tribe because there are no known halibut spawning grounds in the tribe's fishing areas.
In addition to providing important source information, Gao's research helps the fisheries department effectively manage halibut resources by determining whether halibut being introduced to their fishing waters come from healthy or weak stocks.
Determining the origin of the stocks not only helps determine harvest levels, it also helps accurately determine fishing territories.
In addition, Gao and other scientists can also use ear bone studies to identify unique stocks of fish.
For example, it is unknown whether Northwest black cod, another bottom-dwelling fish, is only found in waters off British Columbia and coastal Washington and Oregon, or whether it is comprised of different stocks from more outlying regions. The information helps fishery managers to more precisely track the stock's status and effectively manage the resource.
Both black cod and halibut are important economically and culturally to the Makah tribe. They also command higher market prices than salmon.
Svec say the expertise amassed by the tribe will put a dent in the lack of good information about the actual numbers and behavior of fish stocks passing through Makah fishing areas.
"We are optimistic that Youngwen will bring understanding through his studies," says Svec. "We look forward to what can be accomplished in marine fisheries and marine sciences as a result of his work."