The fishery for California market squid (Loligo opalescens) (Cephalopoda: Myopsida), from 1981 through 2003

The California market squid (Loligo opalescens) has been harvested since the 1860s and it has become the largest fishery in California in terms of tonnage and dollars since 1993. The fishery began in Monterey Bay and then shifted to southern California, where effort has increased steadily since 1983. The California Department of Fish and Game (CDFG) collects information on landings of squid, including tonnage, location, and date of capture. We compared landings data gathered by CDFG with sea surface temperature (SST), upwelling index (UI), the southern oscillation index (SOI), and their respective anomalies. We found that the squid fishery in Monterey Bay expends twice the effort of that in southern California. Squid landings decreased substantially following large El Niño events in 1982−83 and 1997−98, but not following the smaller El Niño events of 1987 and 1992. Spectral analysis revealed autocorrelation at annual and 4.5-year intervals (similar to the time period between El Niño cycles). But this analysis did not reveal any fortnightly or monthly spawning peaks, thus squid spawning did not correlate with tides. A paralarvae density index (PDI) for February correlated well with catch per unit of effort (CPUE) for the following November recruitment of adults to the spawning grounds. This stock– recruitment analysis was significant for 2000−03 (CPUE=8.42+0.41PDI, adjusted coefficient of determination, r2=0.978, P=0.0074). Surveys of squid paralarvae explained 97.8% of the variance for catches of adult squid nine months later. The regression of CPUE on PDI could be used to manage the fishery. Catch limits for the fishery could be set on the basis of paralarvae abundance surveyed nine months earlier

Assessment of Changes of Complex Shoreline from Medium‑Resolution Satellite Imagery

The imagery collected by medium-resolution earth-observing satellites is a powerful and cost-effective tool for the quantitative assessment of shoreline dynamics for water bodies of different spatial scales. In this study, we utilize imagery collected in 1984–2021 on the Middle Peninsula, Virginia, bordering the Chesapeake Bay, USA, by medium-resolution (10–30 m) satellites Landsat-5/7/8 and Sentinel-2A/B. The data was managed in the Earth Analytics Interoperability Lab (EAIL) Data Cube built and configured by the Commonwealth Scientific and Industrial Research Organization (CSIRO, Australia and Chile). The assessments of shoreline change demonstrate adequate agreement with assessments based on aerial photography collected during 1937–2009 by the Virginia Institute of Marine Science, with reasonable disagreement attributed to the differences in the analyzed periods and in the accuracy of land/ water edge detection. Most of the studied coastline was subject to land loss (erosion), in some locations exceeding 3 m year− 1, usually along low-lying sandy beaches. The shoreline segments with man-made structures such as marinas, bulkheads, revetments, and offshore breakwaters demonstrated a significantly lower range of changes as compared to natural reaches. Regular analysis of medium resolution satellite imagery appears to be an effective method for routine assessment of shoreline changes along the land/water edge

Systematic Review and Meta-Analysis Toward Synthesis of Thresholds of Ocean Acidification Impacts on Calcifying Pteropods and Interactions With Warming

Interpreting the vulnerability of pelagic calcifiers to ocean acidification (OA) is enhanced by an understanding of their critical thresholds and how these thresholds are modified by other climate change stressors (e.g., warming). To address this need, we undertook a three-part data synthesis for pteropods, one of the calcifying zooplankton group. We conducted the first meta-analysis and threshold analysis of literature characterizing pteropod responses to OA and warming by synthetizing dataset comprising of 2,097 datapoints. Meta-analysis revealed the extent to which responses among studies conducted on differing life stages and disparate geographies could be integrated into a common analysis. The results demonstrated reduced calcification, growth, development, and survival to OA with increased magnitude of sensitivity in the early life stages, under prolonged duration, and with the concurrent exposure of OA and warming, but not species-specific sensitivity. Second, breakpoint analyses identified OA thresholds for several endpoints: dissolution (mild and severe), calcification, egg development, shell growth, and survival. Finally, consensus by a panel of pteropod experts was used to verify thresholds and assign confidence scores for five endpoints with a sufficient signal: noise ratio to develop life-stage specific, duration-dependent thresholds. The range of aragonite saturation state from 1.5–0.9 provides a risk range from early warning to lethal impacts, thus providing a rigorous basis for vulnerability assessments to guide climate change management responses, including an evaluation of the efficacy of local pollution management. In addition, meta-analyses with OA, and warming shows increased vulnerability in two pteropod processes, i.e., shell dissolution and survival, and thus pointing toward increased threshold sensitivity under combined stressor effect

Relative availability of satellite imagery and ship-based sampling for assessment of stormwater runoff plumes in coastal southern California

Abstract Information about the size and intensity of urban runoff plumes in the ocean has traditionally been collected through ship-based surveys, but sampling from ships in the nearshore zone is weather-dependent because of the rough sea conditions that often accompany storms. Highresolution satellite imagery is an alternative approach for assessing plume properties, but the availability of satellite imagery can also be weather-dependent. Here we compare the logistical availability of ship-based sampling and the quality of satellite imagery for assessing rainstorm-mediated freshwater plumes. The availability of ship-based sampling was assessed by correlating deployment success of three local ships with wind and wave data and then applying those relationships to a longer wind and wave data record. The quality of satellite imagery was assessed by correlating cloud cover and expert opinion about the usefulness of Level 2 SeaWiFS imagery, then analyzing those relationships with respect to cloud cover found in Level 3 AVHRR, SeaWiFS, and MODIS imagery. In the 10 days following storm events, ships were found to be capable of deployment for sampling about 70% of the time, while SeaWiFS produced high quality images only about 23% of the time. The days for which satellite imagery and ship-based data were available often differed, yielding complementary, rather than redundant, information. As a result, plume data were available for about 80% of the study period using one of the methods. The probability of obtaining usable satellite imagery was lowest on the day of a rainstorm and increased during the next 5 days, whereas the probability of obtaining ship-based data was highest on the day of the storm and typically declined in the days following a storm. MODIS sensors provided better coverage than SeaWiFS or AVHRR due to better spectral, spatial, and particularly temporal resolution (twice a day), thereby significantly improving information about plume dynamics

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ABSTRACT Information about the size and intensity of urban runoff plumes in the ocean has traditionally been collected through ship-based surveys, but sampling from ships in the nearshore zone is weather-dependent because of the rough sea conditions that often accompany storms. High-resolution satellite imagery is an alternative approach for assessing plume properties, but the availability of satellite imagery can also be weather-dependent. Here we compare the logistical availability of ship-based sampling and the quality of satellite imagery for assessing rainstorm-mediated freshwater plumes. The availability of ship-based sampling was assessed by correlating deployment success of three local ships with wind and wave data and then applying those relationships to a longer wind and wave data record. The quality of satellite imagery was assessed by correlating cloud cover and expert opinion about the usefulness of Level 2 SeaWiFS imagery, then analyzing those relationships with respect to cloud cover found in Level 3 AVHRR, SeaWiFS, and MODIS imagery. In the 10 days following storm events, ships were found to be capable of deployment for sampling about 70% of the time, while SeaWiFS produced high quality images only about 23% of the time. The days for which satellite imagery and shipbased data were available often differed, yielding complementary, rather than redundant, information. As a result, plume data was available for about 80% of the study period using one the methods. The probability of obtaining usable satellite imagery was lowest on the day of a rainstorm and increased during the next five days, whereas the probability of obtaining ship-based data was highest on the day of the storm and typically declined in the days following a storm. MODIS sensors provided better coverage than SeaWiFS or AVHRR due to better spectral, spatial, and particularly temporal resolution (twice a day), thereby significantly improving information about plume dynamics

Distribution and biomass of seston in the East Atlantic

Biomass of seston in the surface layers of coastal waters off Namibia reaches 1 g/m**2 and decreases with distance from the shore. Two regions of high seston biomass, one northern and one southern, are distinguished. A subsurface maximum of seston biomass, presumably coinciding with the stream of compensating countercurrent, is identified in the 200-500 m layer. Similar vertical distribution of plankton is known in upwelling areas of the eastern shores of the Atlantic and Pacific Oceans and in several other ocean areas, such as the area of the Kuril-Kamchatka Trench. This fact probably indicates that life cycles of pelagic animal forms of various taxonomic groups that inhabit them and phases of their ontogenic migrations are similar

Productive parameters of seawater and epipelagic plankton and mesozooplankton biomass at stations of R/V Akademik Mstislav Keldysh during 1994-1998

Calculated and measured estimations of biomass of small (<3 mm), large (3-30 mm), and total zooplankton were verified (compared). These integral parameters of epipelagic communities were estimated by two methods. We used previously obtained regression equations, which correlate these parameters with water transparency. Measured values of aforesaid parameters were compared with their mean values in waters of different productivity estimated from NASA satellite maps. We compared data collected at fifteen stations in September-December in regions of different productivity in the North Atlantic. In warm regions (to the south of 40°N) measured and calculated values coincide well. In boreal regions in autumn bulk of mesozooplankton descends to deep layers due to seasonal migrations; hence correlation between measured and calculated values is disrupted. It is evident that correlation between water transparency and mesozooplankton biomass (integral index of water productivity) obtained before should be corrected for seasonal variations