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Surfperch
Family of ray-finned fishes From Wikipedia, the free encyclopedia
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The surfperches are a family of percomorph fishes, the Embiotocidae, characterized by deep, laterally compressed bodies and piny dorsal fins. Most species of them are marine, inhabiting coastal waters from Baja California to Alaska, with a few found in Asian Pacific coasts. The only freshwater species, the tule perch (Hysterocarpus traski) is found only occur in California, United States.[2]
Members of this family are easily found by a scaled ridge along the dorsal fins. They are viviparous fishes, in which the embryo is nourished directly by the mother, as well as the yolk. This gives the family its scientific name, from Greek embios meaning 'persistent' and tokos meaning 'birth'. This means the mother fish gives live birth instead of laying eggs.[3]
A unique feature of this family is viviparity—females give birth to live, fully formed young rather than laying eggs. Embryos develop inside the ovary and absorb nutrients and oxygen directly from the mother’s blood supply[4]
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Common species
Barred Surfperch (Amphistichus argenteus), reaching up to 49.5 cm (19.5 in)[5].
Rubberlip surfperch (Rhacochilus toxotes), reaching up to 47 cm (18.5 in)[6].
Tule perch (Hysterocarpus traski), typically less than 15 cm (6 in)[7].
Shiner perch (Cymatogaster aggregata), a smaller, silvery species common in bays and estuaries.[7]
The only known fossil member of the family is Eriquius from the Late Miocene of California.[8][9]
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Distribution
Surfperches are distributed from Baja California to Alaska, making them among the most common nearshore fishes along the Pacific coast. While most species are marine, the tule perch is restricted to freshwater habitats of California’s Central Valley, including the Sacramento–San Joaquin basin, Clear Lake, and Russian River.[7]
The shiner perch (C. aggregata) ranges from Baja California to Port Wrangell, Alaska, occurring in lagoons, estuaries, and the lower reaches of coastal streams. They tolerate low salinity (1–10 ppt) and can survive in temperatures up to 30°C, although they prefer waters below 19°C. Many species migrate seasonally—moving to deeper ocean waters in winter and returning to bays or estuaries in spring to give birth.[7]
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Biology
Summarize
Perspective
Surfperches are viviparous, an uncommon trait among marine fishes. Females fertilize their eggs internally and carry developing embryos for several months.[7]
Reproductive cycle
Most births occur in May or June, coinciding with periods of high food availability. Males often become sexually mature within a few months after birth and establish temporary territories during breeding. [7]
Brood size
The number of offspring increases with female size and varies by population. For example, tule perch in the Russian River produce 12–45 young, while those in Clear Lake produce 25–60 young, reflecting local environmental adaptations.[7]
Feeding and adaptation
Surfperches exhibit highly specialized prey-capture behavior coordinated by both visual and mechanosensory systems. Studies on Embiotocidae kinematics indicate that these fishes rely on the integration of vision and the lateral line system to detect and track small moving prey in nearshore habitats. Their feeding involves a rapid head-thrust motion and jaw protrusion, enabling efficient suction or grasping of benthic invertebrates. This combination of sensory and motor precision allows surfperches to forage effectively in structurally complex environments such as kelp beds and rocky reefs[10] Surfperches feed primarily on benthic invertebrates and small crustaceans (such as amphipods and insect larvae) and occasionally zooplankton.[7] Moreover, the diet of surfperches varies with species and location. The pile surfperch (Damalichthys vacca) feeds primarily on hard-shelled mollusks and crustaceans, while the striped surfperch (Embiotoca lateralis) consumes amphipods and bryozoans. Regional studies show that mouth morphology influences diet breadth—populations with smaller mouths tend to specialize on soft-bodied prey in southern habitats.[11]
Growth and longevity
Most individuals live 5–7 years, reaching 10–16 cm in standard length.[7]
Conservation status
The overall family Embiotocidae remains abundant, but freshwater populations—particularly tule perch—face local declines due to water quality degradation.[7]
Tule perch (Hysterocarpus traski): Though still common in parts of its range, it has disappeared from areas like the Pajaro and Salinas Rivers and much of the San Joaquin basin because of poor water quality and toxic chemical spills. Some isolated populations survive below dams in Putah Creek and the Stanislaus River, while others persist in reservoirs such as those in Southern California, colonized via the California Aqueduct.[7]
Clear Lake tule perch: Despite maintaining stable populations, they remain vulnerable to invasive species, shoreline development, and declining water quality.[7]
Russian River tule perch: These populations have declined since the 1970s due to increased turbidity, agricultural runoff, and flow regulation from dams (Coyote and Warm Springs Dams).[7]
Because of their high sensitivity to oxygen levels and water clarity, tule perch populations are considered important biological indicators of long-term water quality in California’s freshwater systems.[7]
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See also
References
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