Aptos Lagoon: Habitat Use by Steelhead Trout & Tidewater goby

Kristen Kittleson Fishery Resource Planner

County of Santa Cruz

Tidewater Goby & Steelhead TroutLife History

How these species use Aptos Lagoon

Lagoon Dynamics

Other fish that use Aptos lagoon

Tidewater Goby Eucyclogobius newberryi

Photo by Carl Page, ARS Consulting.

Listed as Endangered under the Federal ESARecovery Plan 2005 USFWS

2007 Aerial Photo showing Aptos LagoonTidewater Goby live in the area from about Spreckels Drive to the mouth, where Aptos Creek enters Monterey Bay.

All life stages occur within this area. Gobies can get flushed out to sea during storm flows or lagoon breaching, but do not necessarily survive in the marine environment.

Tidewater goby are small fish (2”) that live on the bottom substrate. They live up to one year. Population numbers can fluctuate greatly depending on habitat conditions in the lagoon.

Tidewater goby can reproduce all year, but peak times are spring and summer. Males dig a nest, attract females and then care for the eggs until they hatch. The population can build up during high reproductive times, then get knocked down by high storm flows or droughts.

Aptos Lagoon

This map shows the distribution of tidewater goby in Santa Cruz County. The closest population is Soquel Lagoon. The connections between these populations is not well understood, but recent research shows that the population in Aptos Lagoon is genetically unique, meaning that there is not a lot of mixing with other populations.

Recently, tidewater goby were present in Aptos Lagoon in 1999, 2004, 2005, 2009 and 2011. This photo shows the area of the lagoon where tidewater goby were found in most of those years.

Kristen Kittleson

We don’t know much about how tidewater goby use the shallow beach channel. Sampling in Fall 2011 did not find any tidewater goby. In Winter 2009 when the lagoon was breached, some tidewater goby were rescued from this area.

Kristen Kittleson

The rip rap in this old structure provides important cover habitat for tidewater goby and may be critical for the local population to survive winter storms.

Kristen Kittleson

Morgan Bond/NOAA Fisheries

Steelhead Trout (Oncorhynchus mykiss) use Aptos Lagoon for migration – both adults upstream and

juveniles downstream. More importantly, steelhead use Aptos Lagoon for summer rearing.

Steelhead are listed as threatened under the federal Endangered Species Act.

NOAA Fisheries is preparing a recovery plan that includes actions to improve Aptos Lagoon for steelhead.

Steelhead and Salmon are Anadromous

(Anadromous comes from the Greek word anadramein, which means to run upward)

• Hatch in fresh water

• Migrate to the ocean

• Return to fresh water to spawn

How do steelhead use lagoon habitat?

• Adult upstream migration

• Juveniles downstream migration and transition to saltwater

• Some juvenile steelhead rear in the summer lagoon

This map shows the distribution of steelhead in the Aptos Creek Watershed. Adult steelhead migrate to stream habitats to reproduce.

Juvenile steelhead take 1-2 years to get big enough to migrate out to the ocean.

Recent research from the NOAA Fisheries Santa Cruz Lab in the Scott Creek Watershed show how important lagoon habitats are to steelhead. This research showed that 85% of the returning adult population reared in the lagoon despite being just 8% - 48% of the juvenile population. In other words, most of the returning adults had reared in the lagoon.

Ellen Freund/NOAA Fisheries

This silver colored juvenile steelhead is called a smolt and is ready to migrate to the ocean. Recent research shows that juvenile steelhead need to be at least 150 mm fork length before heading out to the ocean, just to have a chance at returning as an adult.

Stream 0+

Stream Age 2+

Lagoon 0+

Lagoon 1+

This slide shows how juvenile steelhead rearing in different areas of the watershed grow at different rates. Notice how big the steelhead are that reared in the lagoon!

Dr. Jerry Smith, SJSU

Aptos LagoonGeneral area sampled for steelhead trout-------------------2004-2005 Monthly population estimates were = 500 -2,750(but not very precise)

2011 Population estimate = 420 Almost all the steelhead were greater than 150 mm FL.

This photo shows the San Lorenzo River as a lagoon. In Coastal California, a lagoon forms when streamflows drop and a bar builds up at the mouth of the stream.

Kristen Kittleson

High quality lagoon habitat has good freshwater inflow and an intact sandbar. These conditions create a freshwater lagoon with good habitat conditions and abundant food supply for fish.

Kristen Kittleson

This diagram shows that, when the lagoon is first closed (blocked by a sandbar), there is a layer of saltwater (olive) on the bottom of the lagoon since saltwater is heavier than freshwater. This bottom layer can be low in oxygen and lowers the quality of the lagoon habitat for steelhead and tidewater goby.

KEC

As freshwater from Aptos Creek continues to flow into the lagoon, the incoming freshwater (blue) will help push out saltwater (brown) through the bar. This converts the lagoon to freshwater, which provides good habitat conditions for steelhead and tidewater goby.

KEC

When the lagoon is breached or over-topped by wave action, saltwater rushes into the lagoon and again creates a bottom saltwater layer, which provides poor habitat conditions for steelhead, tidewater goby and the aquatic invertebrates that power the lagoon food web.

Aptos Lagoon is often open in the summer time when a closed lagoon would provide better habitat conditions. In 2011, the lagoon had a bottom saltwater layer with poor oxygen levels most of the summer.

Kristen Kittleson

This photo shows how wave overwash brings saltwater into the lagoon. If there is adequate freshwater inflow, this saltwater can get pushed out again through the bar.

Kristen Kittleson

Other fishes of Aptos Lagoon• Staghorn sculpin• Prickly sculpin• Starry Flounder• Topsmelt• Bay pipefish• Redtail surfperch

Threespine stickleback

Morgan Bond/NOAA Fisheries

Listed as Endangered under Federal & State ESA

NOAA Fisheries is extending the listing to include Aptos Creek

Recovery Plan is in final stages

Coho Salmon (Oncorhynchus kisutch)

Coho Salmon

Adults migrate through lagoon in winterJuveniles use lagoon to acclimate while migrating out to the ocean, but do not

rear in the lagoon like steelheadMorgan Bond/NOAA Fisheries

Thanks toGary Kittleson, KEC, for lagoon graphics

Don Alley, DW ALLEY & AssociatesDr. Jerry Smith, SJSU

Matt Price, GIS Morgan Bond and the other photographers

Kristen Kittleson