The View from 60,000 Feet Evolution and Diversity of Steelhead of Steelhead Ken Currens Pacific Coast Steelhead Management Meeting 2010

West Africa, 1930 Things weren’t always as they are now The present is often more interesting if we know something about the past

Eocene North America Million Million Years Ago Began with rapid warming Tropical forests in Pacific Northwest Polar climates similar to Pacific Northwest today Large lakes and inland seas; none of existing mountain ranges

British Columbia Ma Salmonidae already present Eosalmo driftwoodensis Included Thymallinae Thymallinae Coregoninae Coregoninae Salmoninae Salmoninae Start of long-term cooling trend

Continued cooling allowed dispersal southward Late Miocene (10-5 Ma) The Sabertooth Salmon Oncorhynchyus (Smilodonichthys) rastrosus

Continued cooling allowed dispersal southward Plio-Pleistocene (5-0.1 Ma)

Fossil O. australis In Lake Chapala, Mexico

Distribution of western trouts in North America about 1900 ( from Behnke 1992 )

Diversity of extant western trouts Coastal cutthroat Westslope cutthroat Yellowstone cutthroat Rio Grande cutthroat Colorado River cutthroat Greenback cutthroat Mexican golden trout & undescribed trout Apache trout Gila trout Rainbow trout O. mykiss Bonneville cutthroat Humboldt cutthroat Lahontan cutthroat Paiute cutthroat Whitehorse & Alvord cutthroats California,& Kern golden trouts

reflect Extant distribution does not simply reflect colonization to the south Extant distribution does not simply reflect southward colonization Formation of mountain ranges Shaping old rivers & creating new ones Faulting in Basin & Range Columbia basalts & Snake River flows Volcanic lava floods Glaciation

reflect Extant distribution does not simply reflect colonization to the south Extant distribution does not simply reflect southward colonization Formation of mountain ranges Shaping old rivers & creating new ones Faulting in Basin & Range Columbia basalts & Snake River flows Volcanic lava floods Glaciation No O. mykiss in the Columbia River as recently as 70, ,000 years ago

reflect Extant distribution does not simply reflect colonization to the south Extant distribution does not simply reflect southward colonization Eocene Miocene OligocenePleistocenePliocene Species & Subpecies of North American trout Hucho Brachymystax Salvelinus Oncorhynchus Salmo Oncorhynchus

Two Morphologically Different Forms of Steelhead Trout Inland or fine-scale form with redband trout-like characteristics Coastal form Landlocked “redband” trout with cutthroat-like characteristics (Oncorhynchus sp.)

reflect Extant distribution does not simply reflect colonization to the south Coastal & Inland forms thought to reflect dispersal after isolation & differentiation in glacial refuges

Mexican golden trout & undescribed trout Most primitive forms of O. mykiss occur near Gulf of California Primitive Traits Derived Traits California & Kern golden trouts McCloud redband Upper Klamath redband Goose Lake, Warner,& Chewaucan redbands Fort Rock redband Catlow Valley redband Columbia River redbands Coastal rainbow trout & steelhead White River redband

Earliest O. mykiss evolved around the Gulf of California & dispersed north Gulf of California Sacramento San Joaquin Klamath ? Columbia Oregon Desert Basins Reached Columbia River 32-50K years ago

Gulf of California Sacramento San Joaquin Klamath ? Columbia Oregon Desert Basins Tahoe Glaciation 32K years ago Glacial Lake Missoula Upper Fraser Puget Sound K years ago

C C C C C B B B G G E G B E E E B B B A A B C A A A A E F F F F F F F A A A A C B B C B F A A A A D D D D G G G G B B B B B B C A A A A A A A B B B B B B B CE B B B A A A A C B G Columbia River C C Canonical Variate II I K H H I H H K H Intermediates? Harney (H), Catlow (I) Fort Rock (K) N N M N M N N N Q Q M M M M M M M M M M M M N N N N N N Klamath: Upper Klamath headwater (M), Upper Klamath Lake (N) Coastal Klamath mountains (Q) Canonical Variate I L L L J J J J J O OO O O Sacramento: Goose Lake (L), Warner Lakes (O) Chewaucan (J) L

Sacramento San Joaquin Klamath ?Columbia Oregon Desert Basins Glacial Lake Missoula Upper Fraser Puget Sound Steelhead life-history contributed to greater O. mykiss diversity than often recognized

Sacramento San Joaquin Klamath ?Columbia Oregon Desert Basins Glacial Lake Missoula Upper Fraser Puget Sound Large river systems were more important that glaciation in diversity of O. mykiss Glacial refuges & dispersal Persistence in large river systems 37% 67% Ability to Explain Differences

Sacramento San Joaquin Klamath ?Columbia Oregon Desert Basins Glacial Lake Missoula Upper Fraser Puget Sound Basins now isolated from large river systems played key roles in the evolution of steelhead

Fishing for Ancestral Steelhead in the Oregon Desert Basins, 1985 Things weren’t always as they are now The present is often more interesting if we know something about the past