The ocean sport catch of Pacific halibut in Oregon is estimated weekly by multiplying average catch per boat from interviews by the total effort for each port. In each port, separate catch estimates are made by boat type (charter, private) and trip type (target species such as bottomfish, salmon or halibut, to name a few).
For example, for a particular week, we generate an estimate for Newport of the number of Pacific halibut landed by boat type=charter boats and trip type=halibut. The total coastwide weekly catch is determined by adding together the separate estimates from each port.
Private boat effort. In most ports, ODFW personnel tally private boats as they cross the bar to enter the ocean. Boat counts are made most days, beginning at dawn and usually ending 5 to 6 hours later. Interviews back at the docks are used to determine the proportion of boats by trip type (bottomfish or halibut, for example).
Charter boat effort. Charter offices are the primary source for charter boat counts by trip type. Charter boats are also counted as they cross the bar.
Average catch per boat. Dockside interviews are used to determine average catch per ocean boat by boat type and trip type.
Sampling procedures specify that interviews be conducted randomly and representatively throughout the week. “Fish checkers” do not focus on particular trip types or catch.
A thorough description of the catch estimate procedure is available in a report: Sampling Design of the ODFW Ocean Recreational Boat Survey. (pdf, 1.85 MB)
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EXAMPLE
The following example illustrates how an estimate for Pacific halibut is generated for a particular day in a particular port for a particular boat type and trip type.
Effort
- 130 private boats are counted crossing the Newport bar by the ODFW sampler
- Random dockside interviews in Newport indicate that 50% of the private boats fished offshore for Pacific halibut (=50% of 130 total private boats, or 65 private boats fishing halibut)
Average Catch per Boat
- Random dockside sampling in Newport indicates that private boats fishing offshore for Pacific halibut averaged 3 halibut per boat, and the average length of those halibut was 38 inches (or 18.6 pounds net weight*)
Estimated Catch
- The estimate of Pacific halibut landed in Newport by private boats fishing offshore for Pacific halibut is:
65 private boats x 3 halibut per boat x 18.6 pounds per halibut = 3,627 pounds net weight *
* Net weight is the unit of measure used for catch limits set by the International Pacific Halibut Commission. Net weight is calculated from fish length using a length-weight table and represents the weight of a fish that is dressed (gutted) with its head off.
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