Missing: Tidewater Goby and Candlefish
Two fish used to reside in Redwood national and State Parks, primarily in Redwood Creek (eulachon) and Redwood Creek and Freshwater Lagoon (tidewater goby). Where did they go? Both fish are currently on the list of federally threatened and endangered species published by the U.S. Fish and Wildlife Service and National Marine Fisheries Service. Here are their stories:
Tidewater gobies (Eucyclogobius newberryi) are small, 2 inch (50 mm) long fish typically found in shallow brackish water, usually less than 1 meter deep, in loose aggregations of a few to several hundred individuals. The males dig vertical nesting burrows 4 to 8 inches (10-20 cm) deep in clean, coarse sand. Females roam widely, displaying aggressive behavior, and court individual males that remain close to a nesting burrow. Males protect the enlarged area of their burrows, where fertilized eggs hang from the ceiling and walls. Larvae hatch in 9-10 days, are 0.2 to 0.3 inches (5-7 mm) long, and live midwater in vegetative cover until they reach 0.6 to 0.7 inches (15-18 mm). At this size they become benthic, or bottom-dwelling. Juvenile and adult fish feed on a variety of invertebrates, including ostracods, amphipods, and snails.
Tidewater gobies used to occur in coastal brackish water habitats along the entire length of California. Now, goby populations in many of the historic localities are either very low or extirpated. Known localities include lagoons, estuaries, stream mouths, and “perched” or off-channel habitats that are at least partially connected to the marine environment.
The tidewater goby was listed as endangered in 1994 when it was believed that the species had disappeared from nearly 50% of the coastal habitats within its historic range in California, including its habitats in RNSP. At that time, the state had recently experienced 5 years of drought, and it was thought that populations throughout the range were threatened by a variety of factors. These included modification or loss of habitat due to coastal development, channelization, alteration of water flows, exotic fish introductions, and increased sedimentation and effluent caused by grazing.
In RNSP, there are historic records of tidewater gobies at Freshwater Lagoon from the early 1950s prior to highway construction over the sand spit, and five gobies were collected from the Redwood Creek estuary in the early 1980s. The Redwood Creek specimens are the last known tidewater goby captures in the parks.
So What Happened?
The habitat in the Redwood Creek estuary was degraded when flood control levees were constructed in 1968. Due to altered configuration of the estuary, including the reduction in slough habitat, this area no longer provides suitable rearing habitat for tidewater goby larvae. In Freshwater Lagoon, habitat was lost when highway construction increased the elevation of the sand spit 5 to 15 feet (1.5 to 4.5 meters) higher than the original dune crest. This cut off the entry of salt water into the lagoon, changing the salinity and reducing habitat quality. That coincided with an abundance of introduced predatory fish (largemouth bass and rainbow trout) into the lagoon. No gobies have been detected during surveys in Freshwater Lagoon since before the highway was constructed across the sand spit.
Eulachon or Candlefish
Eulachon (Thaleichthys pacificus), also known as Columbia River smelt, candlefish, or hooligan, are members of the smelt family (Osmeridae). The candlefish namesake is derived from the oily nature of these small fishes, which become so fat as spawners they can be dried, strung on a wick, and lit like a candle. They may grow to 12 inches (30 cm) but most adults are between 6 and 8 inches (15-20 cm). They are shiny dark above and silvery on the sides.
Large spawning aggregations have been documented in the Klamath River and infrequently in other coastal California rivers including the Smith River and Redwood Creek in RNSP. The significance of the spawning runs in the Klamath River and Redwood Creek were revealed in newspaper accounts of great numbers of spawners in February 1919, March 1968, April 1963 and 1969 (Klamath River), and April 1963 and 1967 (Redwood Creek). Eulachon once supported popular recreational fisheries in Northern California rivers.
A California Department of Fish and Game (CDF&G) memo dated May 1, 1973 described eulachon in Redwood Creek in April 23-25 of that year. Surveys were conducted after CDF&G received word that eulachon were running in Redwood Creek and a fisherman had delivered 2,500 lbs (1.1 mt) of eulachon to a local fish processor. The biologists stated in their memo “…The fish were running in such numbers that can only be described as ‘millions’.” This is the last observation of a large run of eulachon in Redwood Creek.
Eulachon are anadromous, meaning they spend their adult lives in the ocean and return to the freshwater stream of their birth to spawn. Eulachon typically spend 3-5 years in the ocean before returning to spawn from late winter through March or April. Spawning grounds are mainly in the lower reaches of larger rivers and may be limited to the portion of the river influenced by tides. In RNSP eulachon have been observed where U.S. Hwy 101 crosses Redwood Creek in Orick, approximately 2.5 mi (4.0 km) from the ocean, although biologists reported in the 1973 CDF&G memo eulachon passing by the mouth of Tom McDonald Creek, 12.5 mi (20.1 km) upstream from the ocean “in greatly reduced numbers”.
Eulachon spawn at night during the months of January, February, and March. After spawning, the eggs, 1 mm in diameter, drift before their sticky outer covering adheres to sand grains and small gravels. The eggs hatch within 20 to 40 days and after hatching the tiny larval fish are transported downstream to the ocean and may rear in estuaries.
So What Happened?
The National Marine Fisheries Service determined the main threats to this species are changes in ocean and river conditions due to climate change. Changes in ocean conditions are the most significant threats to eulachon and their habitats. Warming of marine, estuarine, and freshwater habitats in the Pacific Northwest over the past 50-100 years may be causing problems for eulachon spawning. In the ocean, increased water temperatures may be affecting prey abundance and composition, particularly of zooplankton communities. It is also possible that the flood control levees in lower Redwood Creek and sedimentation negatively altered the habitat in RNSP for eulachon to the point eulachon may no longer be able to persist in this environment.
Major alterations of the landscape for useful purposes (building a better stretch of highway or building levees to protect from flooding), or altered climate may have unforeseen consequences. Some species, like tidewater goby and eulachon, are sensitive to the point that these types of perturbations prove lethal for populations. Restorative actions are needed to bring species like tidewater goby and eulachon back to their historic habitats.