Patterns of larval abundance and early juven~le recru~tment of the sea urchins Strongylocentrotus franciscanus and S p u~p~l r a t u s were examined throughout spring and summer of 1994 and 1995 a t 2 s~t e sIn southern Oregon, USA, lying within the northern reglon of the California Current System. Sea temperature and coastal wind records were used as lnd~cators of local upwelling and relaxation events and combined with a method of aging young sea urchin recruits to link specific settlement events with hydrographic events. In 1994 sea urchin larvae were found in plankton collections from April to July, while in 1995 larvae were found from March to July and occurred in a higher percentage of the collections than in 1994. At the 2 sites, settlement occurred from April to August, was variable between years and sites, but most consistently occurred In June. Larval occurrences in the plankton and settlement events in 1994 and 1995 were associated with water masses between 11 and 12°C. Peak settlement in both years 'ivas associated with warm water rvcnts characterized by a mixed watcr column and northward w~n d stress Settlement rates were 10127 durlng warm events characterized by a s t r a t~f~e d water column and low wlnd stress. Dunng the summer flow regime, onshore transport of larvae may be linked to relaxation events forced by wind from the south and onshore Ekman flow.

In a small shallow fjord with predominantly wind-driven circulation, larvae of the sand dollar Dendraster excentricus (Eschscholtz) do not persist for longer than 2 wk after a local population in the fjord spawns. Changes in distnbuhon and abundance of larval cohorts indicate that larvae are advected out of the fiord and thus contribute to a regional larval pool. A series of plankton samples at the start of 2 reproductive seasons showed that cohorts of larvae are produced during spring tides that expose the intertidal adult population to air. Growth rates of 1 to 3 wk old larvae of D. excentricus and Strongylocentrotus franciscanus in the fjord are comparable to those reared in the laboratory. Later in the season, advanced-stage larvae of D. excentricus are found in surface waters in the fjord; this may enhance their chances of locating suitable habitat for settlement. Many of these advanced-stage larvae have shortened larval arms that may indicate delayed metamorphosis.