Boat-Based Creel Survey
After July 2003
 |
| Hymal Vaimaona - Data Collector (Click on Picture for a Larger Version) |
The details of the Tutuila boat-based fishery sampling program have changed over the years to accommodate changes in the fisheries; but it is still a systematic, random sampling program that stratifies sampling by type of day (either weekday or weekend/holiday) and by fishing method which includes trolling, bottomfishing, combined troll/bottomfishing, boat based spearfishing with and without SCUBA tanks and longlining. For logistical and cultural reasons, Sundays are no longer sampled as effort is extremely low and not similar to other weekend/holiday-type days.
Before July 2003, the data collection for the Boat-based Creel Survey was organized to cover the entire island of Tutuila. It appeared that this approach was time and energy consuming with little results, as the effort was spread out over a large area. More than 90% of the boats were unloading in the main docking area, between Fagatogo and Pago, but less than 50% of the time was used to survey it.
 |
| Carl Steffany - Data Collector (Click on Picture for a Larger Version) |
In July 2003, the data collection team reoriented its survey and focused its efforts on the main docking area, between Fagatogo and Pago. Later one of the data collectors lived in Aunu'u and was able to provide data on boats fishing off of Aunu'u. A new schedule was designed to understand the activity of the local fleet. A new form, the Presence-Absence Form, was designed to record all the activity of all active boats in the area every four hours.
When the Alia longline fleet started to fish in 1995, every boat was making one day trips, leaving early in the morning, and coming back at night and the survey was easy to schedule. As the fishery evolved through the years, this reality faded and in 2003 it was not true anymore. The fish have been becoming harder to find close to shore. The alia fleet has evolved into larger boats, with bigger sets and coolers and inboard engines that can reach farther fishing grounds. Still a part of the fleet was the traditional 28 foot alia, fishing for one day, but a part of it was becoming larger alias, up to 40 feet, which go out for up to 4 days.
 |
| Terry Lam Yuen - Data Collector (Click on Picture for a Larger Version) |
A one month preliminary study was made using the Presence-Absence Form to record the presence-absence of the boats and their activity 6 times a day, from 0000 to 2400. A Week of these results are shown by the Presence-Absence Summary (Weekly Slice). From the monthly Presence-Absence Summary data, the fishing habits, when they leave, when they come back and unload their catch and how many days they stay out fishing can be determined for each boat. This allows us to categorize the longline fishery.
As can be seen from the Presence-Absence Summary (Weekly Slice) example, the boats Fuao II, Galuega Fou and Jimmy Jr. stayed out for three days at a time and come back late at night or in the wee hours of the morning. Their catch is the result of two and possibly three sets of longline gear and the number of sets must be properly indicated on any interview obtained from them so that CPUE can be properly calculated.
 |
| Sitivi Iosua - Data Collector (Click on picture for a larger version) |
Boats like the Southwind IV, Lady Francella and Telefoni followed the old pattern of making one day trips. The Southwind IV returns in the wee hours of the morning while the Lady Francella and Telefoni return in the evening. Boats like the Salvation II, Aeto and Fotolupe stay out for more than 24 hours but less than two days, may make two longline sets while they are out and come back at random times.
Even with the unpredictability of the arrival of those larger boats, it appeared that the best periods to survey and collect fishing data were at night, after 8 pm for longliners and early in the morning for the spear diving and bottom fishing boats. Several boats, which were initially arriving before midnight, started to arrive later, due to travels to farther fishing grounds. We adapted the survey to cover those arrivals, but it required that the data collector works late every night.
 |
| Mika Letuane - Data Collector (Aunu'u) (Click on picture for a larger version) |
Now data collectors sample 4 weekdays a week and sample two Saturdays each month. The collectors work two shifts. The morning shift is from 0500 to 1300 where the technicians fill the first three columns of the Presence-Absence Form and the evening shift is from 1700 to 0100 where where the technicians fill the last three columns.
Referring to the Boat-Based Creel Survey Presence – Absence Form (Previous Version) as an example, a transition from a “Y” or present cell to a “N” or not-present cell for a particular boat indicates that the boat left the dock to go fishing during the “N” cell. Likewise a transition from a “N” or not-present cell to a “Y” or present cell indicates that the boat arrived at the dock after a fishing trip during the “Y” cell.
 |
| Recording the Weight of a Tuna (Click on picture for a larger version) |
Only the arrivals or "N" to "Y" transitions are transferred from the Presense-Absense form to the Particpation Form. In the Boat-Based Creel Survey Presence – Absence Form (Previous Version) example, the Southwind I arrived at 0230 and was not interviewed but was entered on the Boat-Based Survey Participation Form (Current Version). The boat registered as AS522CF, which has no name, arrived at 1300 after being out fishing from 0800-1200 and was interviewed. Its data was recorded on a Boat-Based Creel Survey Interview Form (Current Version) as well as on a Boat-Based Survey Participation Form (Current Version) to count its participation.
The following participation information is recorded on the Boat-Based Survey Participation Form (Current Version), Sample Date · Type of Day · Interviewers · Boat ID or registration number · Fishing Method · Time Observed · Number of Gear · Number of Fishermen · Boat Location · Charter?.
The data items listed below are collected on the Boat-Based Creel Survey Interview Form (Current Version) for each boat where an interview is successfully completed.
Interviewer · Interview Time · Sample Date · Type of Day · Boat Name · Boat Registration Number · Number of fishermen · Fishing Method · Total hours fished · Number of Sets, Hours/Set and Hooks/Set for Longline Interviews · Total catch weight in pounds · Number of gear used · Area fished · Home island · Species Name · Weight in pounds for each species · Number of pieces for each species · Landed Condition · Disposition · Price per pound for each species · Weight of Fish · Length of fish (converted to weight).
If the identification and weight of each individual species is not obtainable, a code for species groupings (e.g., miscellaneous bottomfish) is used. The interview data are later expanded to estimate the total catch per fishing trips and other CPUE measures in Tutuila. The catch per trip estimate is multiplied by the number of trips estimate for each strata to get an estimate of the total catch for Tutuila.
Every month a summary of the Presence – Absence form is created, one week of which looks like the Presence-Absence Summary (Weekly Slice) to track the nature of Alia fishery activity. The Boat-Based Creel Survey Presence – Absence Form (Current Version) has been simplified from its Previous Version. There is no longer a column for fishing method codes or a separate area to enter boats fishing off of Aunu'u. The summary of the number of boats arriving, leaving and interviewed is also gone.
Besides the less than 10 boats still fishing professionally, the activity of the alia feet is today more a subsistence and recreational activity, with more boats trolling or bottom fishing than longlining. The main fleet is now composed of monohull longliners that are more than 50 feet in length and which stay out fishing fishing ground for weeks. We observed between 2002 and now the switch from a small scale fishery toward an industrial fishery with hardly any small boats doing longline fishing. The Boat-based Creel Survey does not even try to cover the activity of these larger boats. Their activity is covered by the Federal Longline Logbooks which they are required to fill out as a condition of their longline permits.
October 1985 - July 2003
In October 1985 a new creel survey sampling system was implemented on Tutuila to provide better coverage and statistics on all boat-based fisheries. Soon afterwards similar monitoring programs were established in the Manu`a Islands where the fishing fleets are centrally located and small enough for statistics to be collected for nearly every trip. The surveyors in the Manu`a islands send their monitoring forms to DMWR in Tutuila for processing.
 |
| NMFS Personnel interviewing a boatowner (Click on picture for a slide show) |
DMWR staff sampled 2 weekdays and 1 weekend/holiday per week. During survey days, counts of total participation are collected, and as many returning vessels as possible are interviewed for catch and effort. Tutuila was divided into six sample areas, of which five, the Fagatogo docks,
It is assumed that the non-sampled area, Vatia, is similar to the sampled areas in fishing activity and success rate. Furthermore, it is assumed that the fishermen interviewed are representative of the entire fishing population and that they give accurate information.
Unless contrary information is available from dockside questioning of knowledgeable persons, a boat is assumed to be "out fishing" if its trailer is at a boat ramp or the boat is missing from its normal berthing area during the 18 hour survey day.
Until 1995 all trips where interviews were not obtained were put in the “unknown” fishing method category. For all of the trips where interviews were obtained a percentage of trips by fishing method was calculated. The unknown trips were then divided up by this percentage and added to the interviewed trips. Since most of these unknown trips were bottomfishing and spearfishing trips and very few real interviews for these fishing methods were obtained, these two fishing methods were under represented in the boat-based creel survey expansion.
Since the vessels involved in these unknown trips was known and since certain boats only engaged in certain fishing methods, their fishing method could be determined by looking at previous interviews obtained from the boat.. From 1995 and after this was done except for vessels engaging in multiple fishing methods at the same time. The fishing method for these remained unknown. The number of unknown fishing trips was greatly reduced and the bottomfishing and spearfishing trips became better represented in the boat-based creel survey.
The participation information was recorded on the Boat-Based Survey Participation Form (Previous Version) for all boats determined to be "out fishing". This information is identical to that recorded on the Boat-Based Survey Participation Form (Current Version) except that there is a Boat Code field in addition to the Boat ID field. An entry is made for each boat by each of the three shifts during the sample day resulting in three entries for each boat on the Participation Form.
The Boat-Based Survey Participation Form (Older Version) didn't have a field to identify charter boats until 2000 when the Previous version was created. The Older Version also had redundant Boat Location and Sample Area fields and had a Boat Owner instead of a Boat ID field for the registration number which caused confusion.
In 1997 the first vessel to make multi-day trips started operating in
In 1999 vessels emerged that made 2-3 day trips and could still be interviewed as part of the Boat-based Creel survey. Since the interview data is generally better than log data, these vessels are treated like normal interviewed vessels in the boat-based creel survey system but their catch is divided by the number of sets they made during their multi-day trips. In 2000 the alias started unloading fish in a gilled and gutted or in conditions other than whole.
Because of this, the Boat-Based Creel Survey Interview Form (Current Version) added to the Boat-Based Creel Survey Interview Form (Previous Version) a Number of Sets field, Hours per Set, and Hooks per Set fields to account for multi-set longline trips and a field for Landed Condition for fish not unloaded in their whole condition.
The Boat-Based Creel Survey Interview Form (Previous Version) added a Registration Number field to the Older Version to improve the identification of the boats and had only one length and weight column for each species instead of two to reduce confusion in collecting data.
1982 - Sepetember 1985
From 1982 to September 1985, DMWR obtained catch statistics by interviewing commercial fishermen at the end of their trips and kept records of as much commercial fishing activity as possible. This data collection method was accurate for trips where interviews were conducted. Yet it was very labor intensive, did not cover all trips, and did not include the small but growing recreational and subsistence fisheries.