266 
National Marine 
Spencer F. Baird { ' V 
Fisheries Service 
Fishery Bulletin 
First U S. Commissioner \ r JS 
NOAA 
?&• established in 1881 ^ 
of Fisheries and founder IQr 
of Fishery Bulletin ’fjgp 
Seasonal distribution of late larval and juvenile 
rockfish [Sebastes $pp.) and associated 
environmental conditions off Oregon and 
Washington: new insights based on genetics 
Mattias L. Johansson 1 
Marisa N.C. Litz 2 
Richard D. Brodeur 3 
Tristan A. Britt 2 
Camilo A. Vanegas 1 
John R. Hyde 4 
Michael A. Banks 1 
Email address for contact author: m.l.johansson@gmail.com 
1 Coastal Oregon Marine Experiment Station 
Oregon State University 
2030 SE Marine Science Drive 
Newport, Oregon 97365 
Present address for contact author: Biology Department 
University of North Georgia 
3820 Mundy Mill Road 
Oakwood, Georgia 30566 
2 Cooperative Institute for Marine Resources Studies 
Oregon State University 
2030 SE Marine Science Drive 
Newport, Oregon 97365 
3 Fish Ecology Division 
Northwest Fisheries Science Center 
National Marine Fisheries Service, NOAA 
2030 S Marine Science Drive 
Newport, Oregon 97365-5296 
4 Fisheries Resources Division 
Southwest Fisheries Science Center 
National Marine Fisheries Service, NOAA 
8901 La Jolla Shores Drive 
La Jolla, California 92037-1509 
Abstract- —Surveys of juvenile and 
larval stages can be useful for man¬ 
agement of commercially important 
marine fishes but require definitive 
species identification. From May 
through October 2005-2008, mid¬ 
water (30-m) trawls collected 78,407 
late-larval and juvenile rockfish {Se¬ 
bastes spp.) in shelf and slope wa¬ 
ters off Oregon and Washington. Be¬ 
cause of their small size and lack of 
pigmentation, we could identify only 
4.1% (3266 individuals) of sampled 
rockfishes to species morphologi¬ 
cally, representing a total of 17 spe¬ 
cies. An additional subsample (2534 
individuals), representing 24 species 
and a 4-species complex, was identi¬ 
fied by sequencing the mitochondrial 
cytochrome b gene and matching se¬ 
quences to a reference data set. In¬ 
complete overlap between identified 
species meant that a total of 29 spe¬ 
cies were identified overall. Commu¬ 
nity analyses showed that rockfish 
collected during the early upwelling 
season (May-June) were distinct 
from samples collected in the late 
upwelling season (July-October). 
Most rockfish were collected from 
outer-shelf or upper-slope stations, 
but distributions varied by month 
and year. Combining genetic and 
morphological identifications vastly 
improved our ability to assess sea¬ 
sonal distributions and abundances 
of planktonic rockfishes and is a 
step toward performing species-level 
surveys for this speciose and com¬ 
mercially important genus. Defini¬ 
tive identification based on visual 
and molecular methods as used here 
provides key information to enhance 
understanding of early-stage rock- 
fish ecology. 
Manuscript submitted 20 December 2017. 
Manuscript accepted 19 June 2018. 
Fish. Bull. 116:266-280 (2018) 
Online publication date: 10 July 2018. 
doi: 10.7755/FB.116.3-4.5 
The views and opinions expressed or 
implied in this article are those of the 
author (or authors) and do not necessarily 
reflect the position of the National 
Marine Fisheries Service, NOAA. 
The larval and juvenile stages of 
many demersal fish species occur in 
pelagic waters, which may connect 
populations (Cowen and Sponaugle, 
2009), and may promote survival of 
a subset of larval production by dis¬ 
persing larvae among diverse habi¬ 
tats in an uncertain, variable envi¬ 
ronment while reducing the risk of 
inbreeding and density-dependent 
mortality (Gadgil, 1971; Levin et ah, 
2003). The dispersal of most larval 
fish seems to be highly diffusive and 
driven by ocean currents, although 
there is evidence that some rock¬ 
fishes (particularly nearshore spe¬ 
cies) remain nearshore due to larval 
swimming behavior or limited water 
movement (Buonaccorsi et ah, 2002, 
2005; Johansson et ah, 2008). Envi¬ 
ronmental conditions also vary with 
ocean currents, and habitat variabil¬ 
ity can affect species abundance and 
diversity. 
In the California Current sys¬ 
tem of the eastern North Pacific, 
the genus Sebastes (the rockfishes) 
is known to be sensitive to shifts in 
environmental conditions associated 
with changes in prevailing currents. 
The rockfishes are among the most 
common of groups found in pelagic 
