SE16-01: Nightlight fishing for atule in American Samoa

A PIFSC sponsored Rose Atoll Marine National Monument and American Samoa Archipelago Ecosystem Science Implementation Workshop was held in May 2015 at the Tauese P.F. Sunia Ocean Center. This workshop pinpointed several high priority American Samoa research items (see workshop report here).  One of the concerns centered on the observations of a decline in the American Samoa atule (also referred to as akule) (Selar crumenophthalmus) runs.  Atule typically live outside the bays and exhibit annual spawning migrations inside bays where they are harvested by village residents.  In addition to providing food, this traditional fishery is deeply rooted in Samoa and is culturally important.

The PIFSC Samoan Archipelago Fisheries Research Cruise sought to provide baseline information about atule by developing a survey to assess the current status of atule.  The operational plan was to use a nightlight, lowered from the NOAA Ship Oscar Elton Sette, to attract atule to the ship, capture them using hook-and-line, and quickly measure before releasing them alive (Fig. 1).  This data would provide insight about the offshore distribution of atule and the population’s size classes.  Future surveys could examine site-specific atule life history traits by collecting otoliths for ageing studies and gonads for reproductive studies.  All of this information would help assess current atule stock status for sustainable management.

Figure 1. Scientist measuring an atule during the Samoa Archipelago Fisheries Research Cruise.

Figure 1. Scientist measuring an atule during the Samoa Archipelago Fisheries Research Cruise.

Despite fairly intensive fishing efforts (every night from 8:00 pm to 12:30 am) offshore from a variety of bays with traditional atule runs (Fagatele, Leone, Faga’sa, and Aoloau) catch rates were disappointing.  Fish schools were difficult to locate.  When located, the ship drifted too fast and they were lost.  However, sample sizes were large enough to identify two primary sizes classes offshore.

Sometimes the best scientific efforts don’t pay out.  But we did learn that using a big ship to catch little fish may not be the best way to survey the atule population.  Scientists are currently discussing other survey methodologies (never give up!).

However, the scientists aboard the NOAA Ship Oscar Elton Sette have been very successful in their other endeavors during this cruise.  Stay tuned to the PIFSC blog for cruise updates as we follow the scientists during the Samoa Archipelago Fisheries Research Cruise.

For a cruise overview, click here.

To read about the SE16-01 Blog 1 – Outreach event with American Samoa Community College Students, click here.

To read about the SE16-01 Blog 2 – Secretary of the Office of Samoan Affairs, District Governor of Manu’a, and District Governor of American Samoa East District visit the NOAA Ship Oscar Elton Sette in Pago Pago, American Samoa.

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