NOAA Ship:   MILLER FREEMAN
Cruise No:   MF 96-13 (FOCI 10MF96)
Area:   Eastern Bering Sea Shelf
Itinerary:   from Sept. 4, Dutch Harbor to Sept. 16, St. Paul

Participating Organizations:
NOAA Alaska Fisheries Science Center (AFSC)
NOAA Pacific Marine Environmental Laboratory (PMEL)
NOAA National Marine Mammals Laboratory (NMML)
University of California Irvine (UC/Irvine)

Cruise Description and Objectives

Fisheries Oceanography Coordinated Investigations (FOCI) is a joint effort by scientists at PMEL, AFSC, the University of Alaska, and other agencies and universities to understand the ecosystem and its biological and physical processes that cause variability of recruitment to commercially valuable fish and shellfish stocks in Alaskan waters. Southeast Bering Sea Carrying Capacity is presently studying the ecosystem and the role of juvenile pollock in it, with the intent to develop and test annual indices of pre-recruit abundance. There are two aspects to field operations for this study: acquisition and analysis of time-series data by which to monitor the ecosystem, and acquisition of data to support research topics that relate to specific processes in the ecosystem.

The objectives of this cruise were (1) to continue acquisition of long-term biological and physical time series; (2) to conduct an acoustic and trawl survey of juvenile walleye pollock for examining horizontal distributions in relation to hydrographic fronts; (3) to collect samples of juvenile pollock for studies on growth, feeding and pathology; (4) to examine vertical distribution of juvenile pollock and zooplankton using nets, and acoustics (5) to examine the impact of midwater and demersal predators upon juvenile pollock; (6) to examine distribution and feeding of seabird and marine mammal predators in the vicinity of the Pribilof Islands.

OPERATIONS SUMMARY

Operation Total

CTD casts	43
Bongo tows	6
MOCNESS tows	21
Methot trawls	28
Clarke-Bumpus tows	28
Anchovy trawls	27
Bottom trawls	16
Acoustic Transects surveyed	15
Chlorophyll samples	244
Fish Predator samples collected	935
Juvenile pollock stomach samples	2917
Juvenile pollock otolith samples	2885
Adult predator length measurements	1269
Juvenile pollock length measurements	5706
Pathology collections	1075
Marine bird and mammal prey collections	70
Stable isotope collections	47

Summary of Cruise

The Miller Freeman departed Dutch Harbor on 4 September to begin work around St. George Island. We first conducted CTD transects on Line D and day and night acoustic transects together with plankton and juvenile fish collections (Fig. 1). We repeated sampling at stations at and on each side of the front using a Methot and anchovy trawl, and MOCNESS, and at selected locations with a bottom trawl. We conducted complete CTD sections, day and night acoustic transects, and fish and plankton sampling along Lines C, B, and A. We next conducted a 48-hour diel study at one location at the front on Line A to examine diel variability at a single location. We returned to Line C to conduct one more daytime acoustic transect and make marine bird and mammal counts. We planned to make bird collections at the end of this transect but the counts were insufficient to warrent small boat operations.

Age-0 pollock were the dominant fish caught in midwater trawls although gelatinous zooplankton dominated the catches by weight. Age-0 pollock were in almost every anchovy trawl and also in most of the Methot trawls. Age-0 pollock abundances were highest in the frontal region of all transects and were higher at the transects north of the islands. Some age-1 and adult pollock were caught in the bottom trawl but flatfishes (rock sole and arrowtooth flounder) were the most abundant fishes caught.

We would like to express our thanks and appreciation to Captain John Clary and crew of the Miller Freeman for an enjoyable and successful cruise. We were very impressed by the cooperativeness and positive attitude of everyone, from the steward's department to the deck crew, survey department and officers.