The 2011 East Japan earthquake generated a massive tsunami that launched an extraordinary transoceanic biological rafting event with no known historical precedent. We document 289 living Japanese coastal marine species from 16 phyla transported over 6 years on objects that traveled thousands of kilometers across the Pacific Ocean to the shores of North America and Hawai'i. Most of this dispersal occurred on nonbiodegradable objects, resulting in the longest documented transoceanic survival and dispersal of coastal species by rafting. Expanding shoreline infrastructure has increased global sources of plastic materials available for biotic colonization and also interacts with climate change-induced storms of increasing severity to eject debris into the oceans. In turn, increased ocean rafting may intensify species invasions.

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Differences in the chemical composition of calcified skeletal structures (e.g. shells, otoliths) have proven useful for reconstructing the environmental history of many marine species. However, the extent to which ambient environmental conditions can be inferred from the elemental signatures within the vertebrae of elasmobranchs (sharks, skates, rays) has not been evaluated. To assess the relationship between water and vertebral elemental composition, we conducted two laboratory studies using round stingrays, Urobatis halleri, as a model species. First, we examined the effects of temperature (16°, 18°, 24°C) on vertebral elemental incorporation (Li/Ca, Mg/Ca, Mn/Ca, Zn/Ca, Sr/Ca, Ba/Ca). Second, we tested the relationship between water and subsequent vertebral elemental composition by manipulating dissolved barium concentrations (1x, 3x, 6x). We also evaluated the influence of natural variation in growth rate on elemental incorporation for both experiments. Finally, we examined the accuracy of classifying individuals to known environmental histories (temperature and barium treatments) using vertebral elemental composition. Temperature had strong, negative effects on the uptake of magnesium (DMg) and barium (DBa) and positively influenced manganese (DMn) incorporation. Temperature-dependent responses were not observed for lithium and strontium. Vertebral Ba/Ca was positively correlated with ambient Ba/Ca. Partition coefficients (DBa) revealed increased discrimination of barium in response to increased dissolved barium concentrations. There were no significant relationships between elemental incorporation and somatic growth or vertebral precipitation rates for any elements except Zn. Relationships between somatic growth rate and DZn were, however, inconsistent and inconclusive. Variation in the vertebral elemental signatures of U. halleri reliably distinguished individual rays from each treatment based on temperature (85%) and Ba exposure (96%) history. These results support the assumption that vertebral elemental composition reflects the environmental conditions during deposition and validates the use of vertebral elemental signatures as natural markers in an elasmobranch. Vertebral elemental analysis is a promising tool for the study of elasmobranch population structure, movement, and habitat use.

Chinook salmon is an anadromous species that varies in size at freshwater emigration, which is hypothesized to increase population resiliency under variable environmental regimes. In California's Central Valley (USA), the majority of naturally spawned juveniles emigrate in 2 pulses: small juveniles (referred to as fry), typically ≤55 mm fork length (FL), emigrate from natal streams in February-March, whereas larger juveniles (smolts), typically > 75 mm FL, emigrate in mid-AprilMay. In some river systems, there is a smaller pulse of emigrants of intermediate size (parr), typically 56 to 75 mm FL. Although the relative contribution of these migratory phenotypes to the adult population is unknown, management activities focus on survival of larger emigrants and most artificially produced fish (98%) are released from hatcheries at parr and smolt sizes. We reconstructed individual length at freshwater emigration for a sample of adult Central Valley Chinook salmon from 2 emigration years using chemical (Sr:Ca and Ba:Ca) and structural otolith analyses. The adult sample was comprised of individuals that emigrated as parr (mean = 48%), followed by smolts (32%) and fry (20%). Fry-sized emigrants likely represent natural production because fish ≤55 mm FL comprise < 2% of the hatchery production. The distribution of migratory phenotypes represented in the adult sample was similar in both years despite apparent interannual variation in juvenile production, providing evidence for the contribution of diverse migratory phenotypes to the adult population. The contribution of all 3 migratory phenotypes to the adult population indicates that management and recovery efforts should focus on maintenance of life-history variation rather than the promotion of a particular phenotype. KEY WORDS: Chinook salmon · Migratory phenotype · Otolith chemistry Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 408: [227][228][229][230][231][232][233][234][235][236][237][238][239][240] 2010 logistic and interpretive limitations. Chemical and structural analyses of fish otoliths, which hold a record of aspects of an individual's environment, provide an alternative approach to generating empirical data on the contribution of migratory phenotypes without the need to recapture individuals (Campana 1999, Campana & Thorrold 2001.Extensive agricultural land use conversion and water development within California's Central Valley (USA) (Fig. 1) have impacted the region's fall Chinook salmon (Moyle 2002), which are listed as a species of concern under the Endangered Species Act (Good et al. 2005). The majority of naturally spawned juveniles emigrate in 2 pulses: small juveniles (referred to as fry), typically ≤55 mm fork length (FL), emigrate from natal streams in February-March, whereas larger juveniles (smolts), typically > 75 mm FL, emigrate in mid-April-May (Brandes & McLain 2001) (Fig. 2a-f). In some river systems, there is a smaller pulse of emigrants of intermediate size (parr), typically 56 t...

Early ocean residence is considered a critical period for juvenile salmon although specific survival mechanisms are often unidentified and may vary by species or life stage. Columbia River spring-run Chinook salmon Oncorhynchus tshawytscha abundance has declined dramatically since the early 1900s. To elucidate mechanisms of early marine survival, we tested the 'bigger-is-better' and 'stage-duration' aspects of the 'growth-mortality' hypothesis, which posits that size and growth rate are important for future abundance. We tested the 'match-mismatch' hypothesis to determine whether early marine growth was related to indices related to regional productivity, including spring transition timing and copepod community composition. We generated estimates of individual size at ocean entry and capture, marine growth rate, early marine migration rate, and emigration timing using data from ocean surveys, genetic stock-assignment, and otolith analyses of juveniles collected across 8 yr between 1998 and 2008. Size at capture and marine growth rate after ~30 d marine residence were positively related to future adult returns, whereas size at marine entry was not. Growth rate was not significantly related to indices of secondary production, but size at capture was significantly greater when lipid-rich copepods dominated. Although future adult abundance was not related to emigration timing, juveniles migrated more slowly when copepod biomass was high, perhaps responding to foraging conditions. Overall, processes during early ocean residence appear to be more important for cohort size establishment than those at marine entry. Approaches that combine genetic and otolith analyses have great potential to provide information on stock-specific variation in survival mechanisms.

Observations of multiple years of geographic variation in [Ba:Ca](otolith) and [Mn:Ca](otolith) in black rockfish Sebastes melanops prompted this study to examine the effects of temperature and water concentration on the otolith incorporation of Ba and Mn in this wholly marine species. The replicated experiment design consisted of two water temperatures (7.4 and 13.0 degrees C) and four water concentrations of Ba:Ca and Mn:Ca. A positive, linear relationship between [Ba:Ca](water) and [Ba:Ca](otolith) was observed at both temperatures. A positive temperature effect was also observed with mean partition coefficients for Ba (D(Ba)) greater in the 13 degrees C than in the 7.4 degrees C treatments (mean = 0.061 and 0.048, respectively). There was no relationship between [Mn:Ca](water) and [Mn:Ca](otolith) although a negative temperature effect was observed. Mean partition coefficients for Mn (D(Mn)) were lower in the 13 degrees C than in the 7.4 degrees C treatments (mean = 0.027 and 0.036, respectively). The data presented support the assumption of a positive, linear relationship between water and otolith Metal:Ca concentrations for Ba:Ca but not for Mn:Ca. Thus, although indicative of residence in distinct water masses, observed variation in [Metal:Ca](otolith) may not reflect variation in water concentration and can be affected by temperature. Caution should be applied in the interpretation of geographic variation of [Mn:Ca](otolith) until the mechanisms regulating its incorporation are more fully understood.

Numerous species of fish and invertebrates move between the continental shelf and estuaries during their early life-history. The physical mechanisms that regulate such movement and the extent of coupling between the near-shore ocean and estuaries are poorly understood. It is unclear how, or whether, similar physical mechanisms regulate transport to the outer coast and between the outer coast and estuarine areas. We used high frequency light trap collections at 2 sites, outer coastal and estuarine, to compare the timing and magnitude of the relative abundance of juvenile fish and crab megalopae. The time series of juvenile fish and crab megalopae were statistically compared with physical variables indicative of wind and tidal conditions to identify potential transport mechanisms. Species examined included juvenile Engraulis mordax (northern anchovy), Sardinops sagax (Pacific sardine), Sebastes melanops and S. caurinus (black and copper rockfish), and megalopae of Cancer magister (Dungeness crab), C. oregonensis and C. productus combined (pygmy and red rock crabs), and Pagurus spp. (hermit crabs). The abundances of juvenile E. mordax and S. sagax and C. magister megalopae in the estuary were significantly cross-correlated with abundances at the outer coast (at 0 to -4 d lags). These data support the idea that estuarine ingress may be a 2-stage process with initial arrival in the near-shore as the first stage and subsequent entrance into nearby estuaries as the second stage. Significant cross correlations between species abundance and physical variables indicative of wind-driven transport, both upwelling and downwelling-related, and tidal transport, specifically the spring-neap tidal cycle, were found at both the outer coast and estuarine site. These data indicate that both wind-driven and tidal transport may contribute to the cross-shelf transport and estuarine ingress of organisms.KEY WORDS: Ocean-estuary coupling · Juvenile fish · Crab megalopae · Upwelling region Resale or republication not permitted without written consent of the publisher

Although dispersal distances of marine larvae influence gene flow and the establishment of population structure, few data on realized dispersal distances exist for marine species. We combined otolith microstructure and micro chemistry of black rockfish (Sebastes melanops) to assess their potential to provide relative estimates of larval dispersal distance. In 2001 and 2002 we measured trace elements at discrete otolith regions, representing the (i) egg/early-larval, (ii) pelagic larval, and (iii) late-larval/early-juvenile periods of fish collected at three locations 120–460 km apart. Discriminant-function analyses based on geochemical signatures at each otolith region accurately grouped an average of 85% (jackknife =  67%) and 87% (jackknife = 81%) of the fish to collection location in 2001 and 2002, respectively. Age at collection ranged from 83 to 174 days and parturition dates within each site were spread over a 22- to 66-day period. Therefore, individuals within sites were not released at similar times. A probable explanation of these data is that larvae from different geographic locations did not mix during ontogeny and possibly did not disperse long distances alongshore. Larval dispersal distances may be appreciably shorter, <120 km, than previously assumed based on models of passive dispersal.