Only a few of the taxa in these tables had similar 

 average abundances in each season. Some of the 

 taxa can be assigned "good" and "bad" years on 

 the basis of either their abundance or frequency of 

 occurrence in samples. Others cannot be assigned 

 with much confidence. Accordingly, on the basis of 

 frequency of occurrence, 1971 was the "best" year 

 for the following copepods: Calanus tenuicornis 

 Dana, Clausocalanus arcuicornis Dana, 

 Ctenocalanus vanus Giesbrecht s.l. and Lucicutia 

 flavicornis Glaus. On the basis of abundance, the 

 following categories can be added to the list: Me- 

 tridia lucens Boeck, 0. spinirostris Glaus, the 

 euphausiid Thysanoessa spinifera Holmes, the 

 pteropod Limacina helicina (Phipps), 

 ctenophores, hydromedusae, echinoderm pluteus 

 larvae, and unidentified annelids. Using the same 

 criteria, 1971 was the poorest year for the copepods 

 Paracalanus parvus Glaus, Pseudocalanus, Ae- 

 tideus pacificus Brodskii, Centropages ab- 

 dominalis, Acartia clausii, A. tonsa Dana, Tor- 

 tanus discaudatus Thompson and Scott, and 

 Epilabidocera longipedata Sato ( = E. amphitrites 

 McMurrich). Also poorly represented in 1971 were 

 the cladoceran Evadne normanni (Loven) and 

 bivalve mollusc veligers. 



A definite pattern emerges from the above 

 classifications. All of the copepod species having 

 their best year in 1971 are basically offshore, 

 warmwater species that can always be found well 

 off the Oregon coast (Peterson and Anderson 1966; 

 Peterson 1972) and which seem to l>ave their 

 highest abundances to the south (Fleminger 1967). 

 Those species which had their poorest year in 1971 

 are all nearshore, coastal species. In fact, some of 

 the neritic species which had their "best" years in 

 1969 or 1970 did not even occur in 1971 

 (Epilabidocera longipedata, T. discaudatus, and 

 A. tonsa; see Figure 6). Fleminger (1967) listed 

 Paracalanus parvus and A. tonsa as temperate- 

 subtropical neritic, and Pseudocalanus, A. clausii, 

 T. discaudatus, and E. longipedata as boreal- 

 temperate neritic. Centropages mcmurrichi is also 

 a boreal neritic species (Gameron 1957). The at- 

 tribute shared by each of the animals having a 

 "poor" year in 1971, is restriction to the neritic 

 zone. Warmwater or cold-water affinities seem 

 unimportant. Even though surface temperatures 

 were much higher in 1971, two important animals 

 with norther affinities and not narrowly restricted 

 to the neritic zone, maintained the same level of 

 abundance as they had in 1969 and 1970: A. lon- 

 giremis and 0. similis. 



100 

 50 



O 



z 



ISO 

 100 



_1L 



150 

 100 

 50 



150 

 100 

 50 



..Jl 



lij 



uL 



J A S 

 1969 



NH- 10 



NH- 5 



NH-3 



NH- I 



I 971 



Figure 6.-Density of Acartia tonsa at NH 1, NH 3, NH 5, and 

 NH 10 in the upwelling seasons of 1969, 1970, and 1971. 



There are important differences between the 

 good upwelling years of 1969 and 1970. A number 

 of taxa were very abundant only in 1970: the 

 copepods Microcalanus pusillus Sars and A. 

 clausii, Calanus nauplii, the cladoceran Podon 

 leukarti (Sars), barnacle cypris, and gastropod 

 veligers. The year 1969 was the better year for two 

 dominant copepod species (Calanus sp. and 

 Pseudocalanus sp.), for the copepods Eucalanus 

 bungii Giesbrecht and A. tonsa, and for shrimp 

 larvae. We do not fully understand these observa- 

 tions. 



The greatest share of the taxa listed in Tables 3 

 and 4 seem to be either equally abundant over all 

 three upwelling seasons (copepod nauplii, 

 euphausiid life history stages, Oikopleura sp., 

 polychaete post-trochophores, small round eggs, 

 euphausiid eggs, and fish eggs), or have uncertain 

 or no relationship to the upwelling seasons. These 

 animals include the copepods Clausocalanus per- 

 gens Ferran, Scolecithricella minor Brady, Me- 

 tridia pacifica Brodskii, Racovitzanus antarcticus 

 Giesbrecht s.l., Gaidius sp., and chaetognaths, 

 barnacle nauplii, and scyphomedusae. 



DISCUSSION 



Upwelling along the Oregon coast was relatively 

 weak in 1971. It was seldom strong enough to 

 create the low temperature-high salinity condi- 

 tions close to the beach that are characteristic of 

 the process. This occurred because there were no 



651 



