Abstract. The coastal Ocean Data Analysis Product in North America (CODAP-NA, Version 2026) represents a major expansion of coastal ocean carbonate chemistry synthesis for North American continental margins. Compared to CODAP-NA Version 2021, the updated product integrates newly available cruise observations spanning more than four decades, substantially increasing both the spatial and temporal coverage of coastal biogeochemical measurements across North American continental shelves. Observations from multiple research programs have been harmonized into a unified, internally consistent format through standardized quality control procedures, enabling large-scale analyses of ocean carbon cycling and ocean acidification along the North American margins. This version comprises 446 cruises, 31,864 hydrographic profiles, and 195,489 discrete data records covering continental shelf environments from Alaska to Mexico in the west and from Canada to the Caribbean in the east from 1981 to 2024. Fourteen variables (including temperature, salinity, dissolved oxygen, dissolved inorganic carbon, total alkalinity, pH on the Total Scale, carbonate ion, fugacity of carbon dioxide, silicate, phosphate, nitrate, nitrite, nitrate plus nitrite, and ammonium) were subjected to extensive quality control. CODAP-NA Version 2026 is available as a merged data product in CSV, MATLAB, and NetCDF formats (https://doi.org/10.25921/h2ff-9d66) through the NOAA Ocean Carbon and Acidification Data System (OCADS: https://www.ncei.noaa.gov/data/oceans/ncei/ocads/metadata/0315529.html). The original cruise data were archived and are accessible via a summary table at the NCEI Ocean Acidification Data Stewardship repository (https://www.ncei.noaa.gov/access/ocean-carbon-acidification-data-system/synthesis/CODAP-NAv2.html).

In Davis Strait, one of two primary Arctic gateways between the Arctic and Atlantic Oceans, the exchange between northward-flowing Atlantic waters and southward-flowing Arctic waters possibly influences deep-water formation in the subpolar North Atlantic. Yet, these circulation pathways and mixing processes, that may be changing, remain uncertain, underscoring the need for new tracers to resolve their structure and variability. This study employs observations from 2022 and 2024 of two artificial radionuclides, 129I and 236U, as new tracers of water masses in Baffin Bay, Davis Strait and the Labrador Sea. Samples were collected during three expeditions: the AZOMP occupation of the AR7W Line in May 2022, Davis Strait Observation Program in October 2022, and the Amundsen Expedition as part of the Refuge Arctic and Transforming Climate Action programme in September-October 2024. By defining the characteristic 129I and 236U concentrations of the main inflowing waters, we examined the distribution, origin and formation of key water masses in Baffin Bay. Our results reveal a substantial contribution (75 %) of West Greenland Shelf Water to Arctic Water on the surface of central Baffin Bay. 236U-rich Arctic-Atlantic-derived water entering Baffin Bay via Lancaster Sound contributes 40 %-60 % to the formation of the Transition Water observed in Baffin Bay. In contrast, cold Arctic Water appears to originate mainly from Nares Strait, and is derived primarily (up to 70 %) from Arctic-Atlantic Water. Notably, the contribution of the Baffin Bay Transition Water to the formation of LSW was significant, exceeding 20 %. However, the binary mixing model showed limitations in quantifying the origin of North East Atlantic Deep Water due to low tracer concentrations and the likely influence of multiple water mass sources. This study offers novel insights into the origin and transformation of water in Baffin Bay and the Labrador Sea and enhances our understanding of the complex interactions between the Arctic Ocean and the subpolar North Atlantic.

Copepod size and energy content are influenced by regional and seasonal variation in temperature and food conditions, with implications for planktivorous consumers such as the endangered North Atlantic right whale (Eubalaena glacialis). Historical data (1990-2020) on Calanus finmarchicus stage CV copepodite prosome length and oil sac metrics were analyzed to determine the extent of variation in individual body size and estimated lipid and energy content in five regions of the Northwest Atlantic continental shelves [Gulf of Maine (GoM), Scotian Shelf (SS), Gulf of St. Lawrence (GSL), St. Lawrence Estuary (SLE) and Newfoundland Shelf]. Large-scale spatial patterns in size and lipid content were related to latitude, indicating that C. finmarchicus CV in the GSL and SLE were historically larger in body size, and had significantly higher lipid content compared with those in the GoM and the SS. The observed patterns of C. finmarchicus CV size and lipid storage capacity suggest that regional variation in whale prey energy content can play a role in the suitability of current and future whale foraging habitats in the Northwest Atlantic, with the larger lipid-rich individuals in the GSL providing a high-quality diet compared with those in southern areas.

The objective of this study was to assess the effect ofenvironmental variability on the dynamics of theAtlantic mackerel (Scomber scombrus L.) stock in the Gulf of St. Lawrence (GSL). We first described the dominant modes of physical and biological (zooplankton) variability using Principal Components Analyses of 40 variables. Two principal modes of variability were identified, a long-term mode (15-20yr) associated with a warming of the GSL and a second mode describing alternating cold and warm periods at a higher frequency (5-10yr). A strong link between physical forcing and the dynamics of zooplankton species known to be important for mackerel was shown. Second, a set of Generalized Additive Models (GAM) was developed to explore how these environmental variations could influence mackerel condition (Fulton's K) and recruitment success (R-s). Optimal GAMs including variations in abundance, species composition and phenology of key copepods improved model performance by 40-50% relative to those considering only physical environmental conditions. The results are consistent with the match-mismatch hypothesis and illustrate the key role of zooplankton dynamics in modulating variations in mackerel K and R-s. Finally, this study showed that large variations in R-s could be caused by varying environmental conditions independently of the influence of stock biomass. Our results strongly indicate that the effect of environmental variability should be considered in the implementation of an ecosystem-based approach to Atlantic mackerel stock management.

Variations in larval fish growth rates are largely the result of variability in biotic and abiotic characteristics of the feeding environment experienced by each individual. An assessment of an individual's overall feeding success (i.e. accumulation of utilizable organic matter) can best be achieved at the time of capture when the relationships among environment, short-term feeding success as defined by gut content and long-term feeding success as defined by accumulated growth can be contrasted. Here, we investigated the relationships between average growth, feeding success, and variability in individual growth and feeding rates across a range of taxa based on a synthesis of studies in which stomach content and otolith growth were measured in the same individuals. Instantaneous measures of feeding success were highly variable and demonstrated a positive yet somewhat limited association with growth rates across all taxa. The strength of the feeding-growth relationships among taxa, and cohorts within taxa, was reflected in the autocorrelation of individual growth rates, suggesting that stable growth was achieved through consistent feeding success. However, when viewed at the individual level, faster growth was achieved in individuals with more variable growth rates, and by inference more variable past feeding success. The dichotomy in these underlying relationships may point to the importance of stochastic events in the development of exceptional individuals in a population, and may be linked to how surplus energy is allocated to individual growth rates. The positive correlation found between feeding success and growth in all taxa is consistent with the growth-survival paradigm for the larval stage of fish. However, both the correlation between feeding success and growth and the serial correlation of growth time-series was greatest in fast-growing species, suggesting that the potential for an early "critical period" regulating survival varies among species, reaching a maximum in fast-growing fish.

Mortality rates of eggs and nauplii are essential for understanding and modelling dynamics of copepod populations. Abundances of Calanus finmarchicus females, eggs and nauplii were determined at 88 stations in the Labrador Sea. Egg production rates (EPRs) and egg and naupliar stage durations were calculated using published relationships with in situ chlorophyll concentration and temperature. The data were used to estimate mortality rates for eggs (M-E), eggs and early naupliar stages (ME-NIII) and naupliar stages (MNI-NVI). Estimated mortality rates in the central basin were higher than those on the shelves and within regions generally M-E > ME-NIII > MNI-NVI. The "Basic Method" for eggs, arguably the most reliable method, gave a high proportion of seemingly erroneous (negative) values. These became positive when a modified estimation formula was used, which assumes that some eggs being laid could not hatch. Egg hatching success is often <100%, but this is rarely considered when calculating mortality rates, although it affects all estimates that include egg abundances and/or EPRs as variables, mostly at low mortality rates. Egg and early life stage mortality rates were correlated with female abundance, but cannibalism may not be the appropriate interpretation. The issues of egg viability and cannibalism require more careful consideration.

Egg production rates (EPRs) were measured for Calanus finmarchicus from the Labrador Sea during annual cruises between May and July from 1997 to 2010. EPRs ranged between 0 and 91 eggs f(1) day(1) at 95 stations. Clutch size (CS) was related to female size (prosome length, PL) and both were smallest on the Greenland (2.76 mm, 55.2 eggs) and Labrador (2.86 mm, 60.1 eggs) shelves and largest in the central basin (2.94 mm, 73.0 eggs). CS and spawning frequency (SF, the proportion of females spawning during a 24 h experiment) both increased with increasing female nitrogen content and decreased with increasing C:N ratio. CS and SF were also positively correlated and both increased with an increasing in situ chlorophyll concentration. The relationships between SF ( day(1)) and EPR (as eggs f(1) day(1) or body C or N day(1)) and in situ chlorophyll concentration were well described by Ivlev functions (r(2) 0.300.34). The residuals from the Ivlev correlations for EPR (but not SF) were significantly negatively correlated with temperature for the central basin (r(2) 0.14), but unrelated over all sub-regions. Over the course of the bloom, as in situ nitrate concentrations decreased, the female N content and the CS decreased and the female C content and C:N increased. Overall, the EPR was most influenced by (i) local feeding conditions (in situ chlorophyll concentration), (ii) the state of the bloom (via effects on female age/condition) and (iii) long-term feeding and temperature history (via effects on female size), although a significant amount of variability remains unexplained.

In the eastern North Water, most of the estimated annual new and net production of carbon (C) occurred during the main diatom bloom in 1998. During the bloom, at least 30% of total and new phytoplankton production occurred as dissolved organic carbon (DOC) and was unavailable for short-term assimilation into the herbivorous food web or sinking export. Based on particle interceptor traps and 234Th deficits, 27% of the particulate primary production (PP) sank out of the upper 50 m, with only 7% and 1% of PP reaching the benthos at shallow (≈200 m) and deep (≈500 m) sites, respectively. Mass balance calculations and grazing estimates agree that ≈79% of PP was ingested by pelagic consumers between April and July. During this period, the vertical flux of biogenic silica (BioSi) at 50 m was equivalent to the total BioSi produced, indicating that all of the diatom production was removed from the euphotic zone as intact cells (direct sinking) or empty frustules (grazing or lysis). The estimated flux of empty frustules was consistent with rates of herbivory by the large, dominant copepods and appendicularians during incubations. Since the carbon demand of the dominant planktivorous bird, Alle alle, amounted to ≈2% of the biomass synthesized by its main prey, the large copepod Calanus hyperboreus, most of the secondary carbon production was available to pelagic carnivores. Stable isotopes indicated that the biomass of predatory amphipods, polar cod and marine mammals was derived from these herbivores, but corresponding carbon fluxes were not quantified. Our analysis shows that a large fraction of PP in the eastern North Water was ingested by consumers in the upper 50 m, leading to substantial carbon respiration and DOC accumulation in surface waters. An increasingly early and prolonged opening of the Artic Ocean is likely to promote the productivity of the herbivorous food web, but not the short-term efficiency of the particulate, biological CO2 pump.

A previous study identified relationships linking variations in the physical environment to fluctuations in zooplankton biomass and Atlantic mackerel (Scomber scombrus) recruitment. Diets of mackerel larvae were compared among four years, one of these years producing an exceptional year-class (1982). Comparisons were standardized for larval length and time of day. Stomach fullness differed significantly among years, with highest values observed in 1982. Stomach content wet weights were significantly larger in 1982 than in 1987 and 1996. The mean weight of Calanus finmarchicus nauplii prey in the diet was also significantly greater in 1982 than in 1985, 1987, or 1996. Female C. finmarchicus were more abundant and more widely distributed in the southern Gulf of St. Lawrence in 1982 compared with 1985, 1987, and 1990. These findings are consistent with the hypothesis of a link between production of copepod nauplii, feeding of mackerel larvae, and recruitment success. However, mackerel size at the end of the first year, as measured on otoliths, varied significantly between years and was smallest in 1982. We propose hypotheses to account for the coupling between high larval food abundance, small juvenile growth, and strong cohorts.

The timing of copepodite recruitment and population development of copepods in spring and early summer (April-July) were compared between the North Water polynya and Barrow Strait, a non-polynya region in the Canadian Archipelago. In the North Water, young copepodites (CI-CIII) of calanoid herbivores were concentrated in the cold and chlorophyll-rich water at the base of the Arctic surface layer, while later stages (CIV-CV) invaded the warmer surface layer. The phytoplankton bloom and the recruitment of the first cohort of copepodites of Calanus hyperboreus, C. glacialis, and Pseudocalanus spp started in May-June, some 1.5-3 months earlier than in Barrow Strait. Consistent with a precocious summer recruitment, population stage structure of these species in early spring (April-May) was more advanced in the North Water than in Barrow Strait. The recruitment in June of Cl of the omnivore Metridia longa was advanced by at least 5 weeks in the polynya relative to Barrow Strait. We found no evidence for an acceleration of the population development of the small Microcalanus pygmaeus, Oithona similis or Oncaea borealis in the polynya.Once the recruitment of young copepodites had started, recruitment success (i.e. % of young copepodites in the population) increased primarily with Chl a concentration for C. hyperboreus, with both sea-surface temperature and Chl a for C. glacialis, and with temperature only for Pseudocalanus spp. Hence, depending on the species, both greater food availability and higher temperature resulting from reduced ice cover contributed to improve reproductive success in herbivorous copepods in the North Water relative to Barrow Strait. A climate-induced reduction of ice cover duration is predicted to favour the population growth of the predominant large calanoid copepods and Pseudocalanus on Arctic shelves. (C) 2002 Elsevier Science Ltd. All rights reserved.

An equation is presented to facilitate estimation of the production of the cosmopolitan cyclopoid copepod Oithona similis. The egg hatching rate was studied from Arctic, subarctic and temperate waters covering a temperature interval from -1 to 20.5degreesC. Within this temperature range the hatching rate (HR) increased from 0.03 to 0.42 d(-1). Results from all experiments were fitted to a function HR (% d(-1)) = 4.2176 + 1.7545T (r(2) = 0.98; p < 0.0001), where T = temperature. When combined with site-specific information on temperature, egg:female ratios and the carbon content of females and eggs, secondary production of this ubiquitous species can be readily estimated.

Between 1982 and 1991, an annual survey of stage I egg production of Atlantic mackerel (Scomber scombrus) was conducted in June/early July in the southern Gulf of St Lawrence. We investigated the relationship between interannual variability in biomass of zooplankton, determined from the archived survey plankton samples, and mackerel recruitment, estimated from the proportion of three‐year‐olds in the catch of the commercial fishery. Zooplankton biomass varied by a factor of 2.5, primarily owing to fluctuations in the >1000 μm size fraction. The index of mackerel recruitment fluctuated by a factor of ≈20 and was positively related (linear regression: P < 0.05; n = 10) to variations in the zooplankton biomass. Both mackerel recruitment and zooplankton biomass were negatively related (linear regression: P < 0.05) to RIVSUM, a measure of freshwater discharge from the St Lawrence River system and an index of variability in the region's climate. Three hypotheses are put forward to explain these observations: (1) there is a strong link between interannual variation in abundance of copepod females, which produce prey for mackerel larvae, and larval survival; the exceptional recruitment and subsequent year class resulted from an exceptional production of Calanus finmarchicus nauplii; (2) years of high zooplankton biomass provide better feeding conditions and consequently higher survival of mackerel juveniles; and (3) mackerel recruitment and zooplankton biomass are independently under the control of an underlying physical process, without strong trophic linkage. The first hypothesis is supported by a study of copepod species composition and female abundance conducted for four of the survey years. At the present time, none of these hypotheses can be ruled out.

This paper examines the use of inductive learning to categorize natural language documents into predeened content categories. Categorization of text is of increasing importance in information retrieval and natural language processing systems. Previous research on automated text categorization has mixed machine learning and knowledge engineering methods, making it diicult to draw conclusions about the performance of particular methods. In this paper we present empirical results on the performance of a Bayesian classiier and a decision tree learning algorithm on two text categorization data sets. We nd that both algorithms achieve reasonable performance and allow controlled tradeoos between false positives and false negatives. The stepwise feature selection in the decision tree algorithm is particularly eeective in dealing with the large feature sets common in text categorization. However, even this algorithm is aided by an initial preeltering of features, connrming the results found by Almuallim and Dietterich on artiicial data sets. We also demonstrate the impact of the time-varying nature of category deenitions.