The objective of this cruise was to conduct a late larval survey of walleye
pollock, and to continue studies of how hydrographic and/or atmospheric
events affect the growth and survival of pollock larvae in Shelikof Strait.
Secondary objectives were to collect data for analyzing the effects of
El Nino on the distribution of ichthyoplankton, and to collect data for
analysis of plankton production.
Operations:
CTD casts 18
Bongos, 60 cm 131
Bongos, 20 cm 4
Tucker trawls 11
Satellite tracked buoy deployment 2
SeaCat CTD casts 145
Samples Collected:
Chlorophyll samples 78
Nutrient samples 93
Microzooplankton samples 24
Larval pollock otoliths 891
Summary of Cruise:
The cruise began with occupation of a series of FOCI grid stations outside
of Woman's Bay, around Afognak Island and down Shelikof Strait. Larval
fish were sampled with a 60cm bongo. During this phase, line 8 in Shelikof
Strait was sampled for hydrographic and plankton profiles.
Phase 2 was to conduct an ichthyoplankton survey over a grid of stations
extending from about Mitrofania Island to Kodiak Island. All sampling was
with a 60cm bongo. The first stations sampled were a series of near coastal
stations beginning near Kodiak Island extending southwestward. Around Mitrofania
Island, offshore stations were occupied while heading back towards Kodiak
Island A total of 131 60 cm bongo net tows were conducted to determine
the distribution and abundance of pollock larvae (Figure 1).
The next phase of operations was occupation of 11 stations for the El
Nino study in the sea valley and exit region of Shelikof Strait. Sampling
was conducted with Tucker trawls. At line 8 and at the El Nino stations,
microzooplankton, chlorophyll, nutrients, and irradiance were sampled during
14 CTD casts.
Table 1. 5MF98 Cruise Summary of operations.
