Younger
Fish, Older Fish:
Protecting Pacific Albacore Populations
from Overfishing
Conservation, Fish Age and Size
While fisheries management practices have improved enormously in recent years, some past management failures can be traced directly to a general lack of information about the size and status of younger fish populations. In most fisheries, fishermen harvest only large, mature fish while actively avoiding younger, smaller fish. As a result, a great deal of information can be available to scientists and fisheries managers on the mature adult populations... while the condition of younger populations often remains a mystery.
Not knowing how many younger fish will grow to maturity can obviously result in serious problems for fisheries managers and fishermen alike. A farmer could not plan his annual harvests without knowing how many acres of crops had been planted in his fields. Likewise, fisheries managers need to have reliable information about how many younger fish will eventually reach adulthood so that future harvests of the larger adult fish can be planned and properly managed. Harvesting a number of smaller, younger fish can therefore be very useful for better understanding the overall status of a fish population -- and to prevent overfishing.
|
Combination
Harvests In the case of the Pacific albacore tuna fishery, trollers using hook-and-line jig gear harvest some of the surface-swimming albacore in the 3 to 5 year classes (i.e., "troll-caught" albacore), while other fishing gears target older, larger albacore from much deeper waters. The jig-boat fishery can thus serve as a kind of "early warning system" if something goes wrong with the larger, older albacore populations. |
Related Animated Movie |
It is important to recognize that when harvest records documenting population trends in the younger year classes are not available from fishermen, fisheries management agencies and scientists must then do their best to gather information about these populations by themselves. Because there are very few scientists and research vessels available for fishery sampling projects, it can be very difficult for scientists to collect enough data to thoroughly assess the status of species that often span over millions of square miles of ocean.
Limiting
Factors in the
Pacific Albacore Troll Fishery
The Pacific albacore troll fishery is a relatively low production fishery limited by a range of unavoidable factors. The first limitation rests in the way the 3 to 5 year old albacore behave. Since albacore do not swim in tightly formed schools and spread out from one another, each must be caught individually rather than in groups (i.e., with encirclement nets). This means jig boat fishermen cannot catch hundreds of albacore at a time or thousands of albacore at a time -- even when there are hundreds or thousands of albacore in the immediate vicinity of a jig boat. It means that jig boat fishermen must catch albacore one at a time, which automatically restricts harvest rates to a much greater degree than in many other commercial fisheries.
Each jig boat is also functionally restricted to using no more than 10 to 20 jigs (i.e., individual fishing hooks on individual fishing lines) because to what is sometimes referred to as "the tangle factor." Each hook and it's fishing line must be placed far away from other lines to prevent tangles. By comparison, albacore longliners use hundreds or even thousands of hooks at a time -- which is still acceptable, so long as their overall harvests remain within sustainable levels.
The enormous size of Pacific albacore fishing areas is also a significant factor that helps to protect albacore from overfishing.
|
The Pacific Ocean is many times the size of the United States (shown here in red)
|
Because albacore are a highly migratory species that routinely travel across the entire Pacific Ocean, their populations are spread out over vast areas. The Pacific is the largest geographical feature on the globe, encompassing more than 60 million square miles -- whereas the total land mass of the entire United States amounts to less than 4 million square miles. |
|
|
|
To put the vast size of the Pacific into perspective, imagine traveling across the United States in an ordinary golf cart. A trip from Lewiston, Maine to San Francisco, California spans across 3,237 miles. A car could make the trip in less than seven days, yet it would take a golf cart traveling at a steady 11 MPH more 36 days to complete the same journey. Most jig boats move at about the same speed as golf carts, and they routinely work and travel within areas even larger than the United States. |
|
Formal Pacific Albacore
Fisheries Management Programs
In addition to the limiting factors above, the Pacific albacore troll fishery is subject to rules and restrictions under several national and international fishery management programs. The largest of these programs is the new Central and Western Pacific Fisheries Convention, which is charged with setting fishing rules for fleets from more than two dozen participating nations.
Then the newly amended US / Canadian Albacore Treaty will regulate the number of Canadian albacore boats that are allowed in US waters, and visa versa. Canadian trollers are also managed through the Canadian Department of Fisheries and Oceans, while US trollers fall under the US Magnuson / Sustainable Fisheries Act.
Finally, trollers from the Pacific Northwest are monitored and regulated through the Pacific Fisheries Management Council, while Hawaii trollers fall under the Western Pacific Fisheries Management Council; both Councils have developed formal Fishery Management Plans that address albacore harvests.
Summary
Both younger and older Pacific albacore tuna are harvested; harvesting some of the younger albacore provides not only food for consumers, but also critically important data to better monitor and manage the overall albacore harvests over time. The small number of hooks used, the biology and habits of albacore tuna, and the size of the albacore fishing areas involved naturally limit jig boat harvests. Pacific albacore harvests also fall under the regulatory authority of a number of international, regional, and domestic management agencies.