Point of View: Quantifying nearshore fish communities in Kachemak Bay

Alaska’s forage fish species, like Pacific herring, saffron cod, and Pacific sand lance, play a crucial role as food for adult salmon and other fish predators.

Understanding the abundance and habitat needs of these forage fish becomes increasingly important as salmon populations respond to warming oceans.

The Kachemak Bay National Estuarine Research Reserve (Reserve), in Homer, has long recognized that coastal river mouths and adjacent beaches within the Kachemak Bay estuary offer vital rearing habitat for juvenile salmon, forage fish, and other species living within the nearshore environment.

Working with KBNERR research technician and University of Alaska Fairbanks graduate student Chris Guo, the Reserve has undertaken a two-year study to quantify ecological variations on species abundance within these nearshore habitats.

During the summer of 2018, Reserve staff, under Guo’s guidance, seined (netted) forage fish and juvenile salmon and collected zooplankton samples for identification from seven riverine estuaries within Kachemak Bay (Glacier Spit, Halibut Cove Lagoon, China Poot, Tutka Bay, Barabara Creek, Seldovia Harbor, and Anchor Point).

These sites were selected based on variations in fresh water flow and ocean currents.

Water chemistry data (such as temperature, salinity, and pH), and physical parameters (including slope, substrate and rates of freshwater flow) were also collected.

In 2019 Guo and other Reserve staff will revisit some sites and add a few new sites to conduct a more intensive sampling of fish communities and physical habitat parameters.

Their goal is to sample multiple times during the tidal cycle and evaluate various habitat parameters like algal rafts near shore and sediment types.

The resulting data will yield a deeper understanding of important habitat parameters and related fish communities within Kachemak Bay.

So far, saffron cod have proved to be the most abundant near-shore species captured during seining events.

Juvenile salmon were prevalent in the early summer while sand lance (and to a lesser degree herring) were abundant in the later part of the season.

KBNERR continues to thrive because of the support and engagement of the greater Homer community and numerous area partners. Reserve staff need and want your input.

Contact KBNERR on their website at https://accs.uaa.alaska.edu/kbnerr/, via email at uaa_kbnerr@alaska.edu or call the main line at 907-235-4799.

Jessica Shepherd, Education Coordinator for Kachemak Bay National Estuarine Research Reserve.