FATE Final Report Project Title: Ichthyoplankton-based indices of climate and ecosystem change Principal Investigators: R. Brodeur, R. Emmett, W. Peterson /NMFS/NWFSC and G. Boehlert /HMSC, OSU, Newport OR. Goals: This project directly contributes to FATE’s goal of evaluating the response of marine fish populations to different types of climate forcing by identifying the environmental factors and climatological indices that most influence fluctuations in ichthyoplankton abundances and assemblages, and provides a model to forecast changes in the population structures of fish early life-stages in the northern California Current. In addition, our multivariate model attempts to predict variations in the abundances of ecologically and commercially important adult fish stocks (e.g., northern anchovy, Pacific sardine, Pacific herring, flatfish) based on ichthyoplankton abundances and distributions. We believe that ichthyoplankton abundances and population structures are useful and cost-effective performance indicators of fish stocks, and can provide an early warning of major shifts in the productivity of key fish stocks, as well as providing a tool to monitor current trends in ocean conditions, fish production, and ecosystem dynamics. Approach: Recognizing that ecosystem indicators should be practical, pragmatic, easy to measure and useful to managers, we propose to develop a suite of performance indicators that are capable of addressing the type of impacts relevant to ecosystems. Our long-term goal is to close the time line between detecting changes in the physical environment and detecting changes in ecosystem structure. In the case of the northern California Current, we need to capture seasonal, interannual, and decadal variations in physical and biological ocean conditions that relate to fish recruitment variability. We include a focus on those zooplankton species that are the chief prey items of fishes with the hypothesis that reduced abundances of prey in any given year (caused by physical oceanographic variability such as reduced upwelling, anomalous transport or El Niño events) may lead to reduced recruitment of some fishes. Work Completed: We have completed our analysis of historical zooplankton samples for ichthyoplankton composition with respect to 4 major projects. For the first project, plankton collections were examined from two stations off the mouth of the Columbia River sampled up to 10 times per year from 1999 to 2004, providing ample data to test relationships between environmental indices and the distribution and abundance of eggs and larvae with time. A total of 3,565 larval and juvenile fishes and 155,302 fish eggs were collected. At least 34 taxa were collected representing 17 families, with the family Pleuronectidae having the greatest number of taxa (9). The northern anchovy, Engraulis mordax, had the highest densities of eggs and larvae and accounted for 76% of all ichthyoplankton. The peak of anchovy egg abundance varied interannually and occurred in June of 1999, 2001, 2002, July of 2000, and in May of 2003 and 2004. Variations in peak spawning correlated with temperature and outflow regimes from the Columbia River. A poster from this work entitled “Seasonal and Interannual Variation in Ichthyoplankton Collected off the Mouth of the Columbia River “ was presented at the 2005 CalCOFI meeting in La Jolla and a manuscript (Parnel et al. MS) is presently undergoing internal review for eventual submission to Fishery Bulletin. A second project involves looking at vertical distribution of larvae off the Newport Line. We examined depth-discrete MOCNESS samples that were collected as part of the GLOBEC program to identify the interannual and seasonal variations in ichthyoplankton along the Newport transect. We also examined additional MOCNESS data at a single station taken throughout the diel period to examine diel vertical distribution of the larvae. The 281 samples collected between April and September of the two study years yielded 4944 fish larvae comprising 72 taxa in 30 families. The most abundant taxa collected were: Sebastes spp., Stenobrachius leucopsarus, Engraulis mordax, Lyopsetta exilis, and Tarletonbeania crenularis. Relatively few larvae were found at depths >100 m, while highest larval densities generally occurred from 10-50 m. However, E. mordax larvae were most often found in the upper 10 m of the water column, while L. exilis concentrations were highest from 50-100 m. Larval diversity and concentration were higher offshore (40-72 km) than onshore (8-24 km). With the exception of L. exilis, larval densities were positively correlated with temperature and negatively correlated with salinity (P<0.0001). We presented results from this work at the 2005 Annual PICES meeting in October and the CalCOFI meeting in November, 2005, and have publications coming from this work in Marine Ecology Progress Series (Auth and Brodeur 2006) and Fishery Bulleting (Auth et al. 2007). We also have analyzed egg and larval data from broad NMFS surveys conducted from 1994-98 off Oregon and Washington to assess egg distribution and production of Pacific sardines off our coast as part of a larger study of the importance of this species in the Northern California Current region. Sardines were by far the dominant taxa collected in these surveys, consisting of about 40% of the total. Highest egg densities were observed in June 1996. During all years, eggs were associated with surface temperatures between 14-15°C. Results from this work were presented at CalCOFI and the Trinational Sardine Meeting iin 2006 and appeared as part of a publication in CalCOFI Reports (Emmett et al. 2006). Finally, we examined the abundance patterns of ichthyoplankton from two stations on the Newport line from 80 collections made from 1996-2005 in relation to historical records collected in the 1970s and 1980s. We have documented unusual distributions and occurrences of eggs and larvae compared to the historical record including anomalous spawning of Pacific hake, jack mackerel, and sardines off Oregon and Washington. The ten most dominant taxa comprised approximately 87.3% of the total catch. Density of fish larvae was highest in January to March, whereas diversity peaked from March through May. Both overall diversity and density of larval fishes were relatively constant through the period 1996 to 2003, with a dramatic decrease in these metrics since 2004, especially for winter-spawning (January-May) species. During cool years (1999-2002), the assemblage was dominated by northern or coastal taxa such as sand lance Ammodytes hexapterus, sanddabs Citharichthys spp., and smelts Osmeridae, whereas in warm years (1997-98 and 2003-05), southern or offshore taxa such as English sole Parophrys vetulus, northern anchovy Engraulis mordax, and rockfishes Sebastes spp. were more important. These changes were related to concurrent shifts in the copepod biomass and composition off Oregon during cold and warm environmental regimes. A paper from this work was presented at the Larval Fish Conference in Lake Placid New York in 2006, CalCOFI Conference in Monterey in 2006, and as a poster at the AIFRB Conference in Seattle in 2007. We will also be presenting a paper at the PICES Annual meeting in Victoria BC this coming October. A manuscript from this work has been submitted to Marine Ecology Progress Series. We are in the process of conducting a detailed statistical analysis of the relationship between larval abundance and large-scale environmental measures. Larval fish abundance and species composition examined along the NH line off the coast of Oregon from 1996-2005 were compared with historical data from the 1970s and 1980s to evaluate decadal, seasonal and annual variability of ichthyoplankton. Our results indicate that the most abundant species from 1996-2005 differ from those of earlier decades. Climate indices, such as Pacific Decadal Oscillation (PDO), Northern Oscillation Index (NOI) and the Multivariate ENSO Index (MEI) and local environmental factors, such as upwelling, sea surface temperature, and wind stress were related to observed changes in ichthyoplankton abundance and structure using a Generalized Additive Modeling approach with appropriate lag periods for the various environmental variables. We found that the large scale climate indices such as the PDO and MEI explained more of the variance in overall larval fish abundance and diversity as well as that of the dominant species than the more local factors. Continued comparative analysis of this data will help clarify whether ichthyoplankton from a single transect can serve as an indicator for changes in adult fish stocks in the northern California Current. A manuscript is presently in preparation from this work (Auth et al. MS). Applications: We have provided our entire ichthyoplankton database to the NWFSC FRAM Division who do the stock assessments on all groundfish stocks along the west coast. We have also provided information on larval sardines at the Trinational Sardine Conference the last few years which has helped in the assessment of this species. Our documentation of a major northward shift in the spawning area of Pacific hake will assist managers of this species in their assessment of the recruitment and distribution of adult stocks, We are now working with a visiting scientist, Dr. Gordon Kruse, who is developing an integrated recruitment simulation model for English sole that will incorporate our density and size measurements for this species. We also provided ichthyoplankton data to Randy Clark who is putting together a biogeographical atlas of the distributions of select taxa along the west coast. Publications: Auth, T. D. (MS) Distribution and community structure of ichthyoplankton from the northern and central California Current in May 2004-2006. To be submitted to Fish. Oceanogr. Auth, T.D. and R.D. Brodeur. 2006. Distribution and community structure of ichthyoplankton off the Oregon Coast in 2000 and 2002. Mar. Ecol. Prog. Ser. 319:199-213. Auth, T.D., R.D. Brodeur, and K.M. Fisher. 2007. Diel vertical distribution of an offshore ichthyoplankton community off the Oregon coast. Fish. Bull. 105:313-326. Auth, T.D., R.D. Brodeur, H.L.