Robert M. Cerrato

Histological Analysis of an Outbreak of QPX Disease in Wild Hard Clams Mercenaria mercenaria in New York

Abstract Over 600 hard clams Mercenaria mercenaria from a wild population in Raritan Bay, New York, were examined histologically to assess the extent and intensity of quahog parasite X (QPX) disease in the fishery area. The overall rate of positive samples was 5.8%. A further 5.1% of clams had inflamed lesions suggestive of QPX infection but no QPX organisms were observed. In over half of the QPX-positive cases, infections of the viscera were involved. The significant proportion of visceral infections and the appearance of the pathogen in the gonads of clams are previously unreported presentations of QPX disease. Visceral infections are of concern for fisheries because they involve significantly larger numbers of parasites and higher biomass than mantle-only infections.

Linking phytoplankton community composition with juvenile-phase growth in the Northern QuahogMercenaria mercenaria (L.)

This study examined whetherMercenaria mercenaria (L.) (quahog) growth is influenced by variability in phytoplantkon community composition in the waters of Long Island, New York. Field studies conducted during 1999 and 2000 compared juvenile quahog growth and phytoplankton assemblages between West Sayville (WS), an embayment in Great South Bay along Long Island’s south shore where quahog landings have recently declined, and Oyster Bay (OB), an embayment on Long Island’s north shore where quahog landings are still high. Quahogs grew better at OB than WS during both study years. Centric diatoms were typically the dominant phytoplankton species at OB, and pennate diatoms and dinoflagellates characterized WS. At WS, the phytoplankton community consisted of heterotrophic dinoflagellates during a brown tide in 2000 and pennate diatoms afterward. Nanoflagellates were abundant (105–106 cells ml−1) at WS throughout the summer of 2000. Multiple regression analysis revealed a significant effect of site and temperature on individual clam biomass during both years, but brown tide was only significant during 2000. Biomass comparisons of dominant phytoplantkon taxa with laboratory physiology studies showed that 0B, with its abundance of centric diatoms, likely represented a more nutritional diet for quahogs than pennate diatoms, which were abundant at WS. Small flagellates, which were common at WS, may also have been important for sustaining growth during some months. Variability in plankton assemblages between OB and WS likely represented two distinct, diets that were critical influences on clam growth.

Biology and Ecology of Long Island Sound

Many compelling management issues in Long Island Sound (LIS) focus on how organisms respond to stresses such as commercial and recreational harvesting, eutrophication, hypoxia, habitat degradation, invasion of non-native species, ocean acidification, and climate change. In order to address these complex problems, we must first understand the factors controlling biological processes and how organisms interact ecologically. This chapter provides an overview of the major groups of organisms occupying the dominant habitats of LIS.

Diet Composition and Feeding Habits of Common Fishes in Long Island Bays, New York

Abstract Developing models in support of ecosystem-based management requires knowledge of trophic dynamics of ecologically important species. A paucity of data on these dynamics for Long Island finfish is hindering development of ecosystem models required by recent legislation. In this study, we analyzed stomach contents of common fishes collected from Port Jefferson Harbor, Great South Bay, and Shinnecock Bay between May and October of 2007 and 2008. General diet composition was described by percent by number (%N), percent by weight (%W), percent frequency of occurrence (%0), and percent index of relative importance (%IRI) for seven species: Paralichthys dentatus (Summer Flounder), young-of-the-year (YOY) Pomatomus saltatrix (Bluefish), Prionotus evolans (Striped Searobin), Stenotomus chrysops (Scup), Scophthalmus aquosus (Windowpane Flounder), Raja eglanteria (Clearnose Skate), and Morone saxatilis (Striped Bass). Temporal diet composition was estimated for the consistently abundant YOY Bluefish, Summer Flounder, and Scup, where most nseason > 25. Subsampling of large catches of YOY Bluefish and Scup led to investigation of diet composition by cluster sampling. Important prey included Crangon sp. (sand shrimp), Cancer irroratus (Rock Crab), and forage fishes. Pseudopleuronectes americanus (Winter Flounder), once a common prey item in stomachs of piscivorous Long Island fishes, contributed ≤ 6.7 %O and ≤ 1.6 %W to the diets of Summer Flounder, Striped Searobin, Striped Bass, and YOY Bluefish. These changes may be due to shifts in the abundance of prey items or changes in spatial overlap of predator and prey.

Growth and Mortality in Coastal Populations of Winter Flounder: Implications for Recovery of a Depleted Population

Abstract We studied growth, mortality, and settlement distributions of juvenile Winter Flounder Pseudopleuronectes americanus in two bays of Long Island, New York, to better understand localized population dynamics of a species experiencing a protracted population decline. Juvenile mortality in Long Island bays ranged between 0.02 and 0.04 per day and was as high as or higher than values reported for other systems. Settlement distributions had multiple peaks (cohorts) occurring between March and late July in 2007 and between February and May in 2008. The presence of multiple cohorts limited the usefulness of field-derived, length-based estimates of growth, resulting in unrealistic values compared with otolith-based measures (field based: -0.05 to 0.25 cm/d; otolith based: 0.05–0.06 cm/d). Thus, we recommend the use of otolith methods or the repeated measurement of individuals to estimate growth of juvenile Winter Flounder. Otolith-based growth rate was significantly higher for Port Jefferson Harbor during 2007 than for all other year × location combinations. Together with previous research showing genetic differentiation and migratory diversity, our finding of multiple spawning cohorts in Long Island Winter Flounder suggests a degree of isolation, and local management will be needed to support healthy populations. Future research to determine adult spawning, migratory behavior, stock structure, duration of the larval period, and settlement timing is required to unravel the complex behavior of Winter Flounder.

Diel Variations in Survey Catch Rates and Survey Catchability of Spiny Dogfish and their Pelagic Prey in the Northeast U.S. Continental Shelf Large Marine Ecosystem

Abstract This study examines the potential uncertainty in survey biomass estimates of Spiny Dogfish Squalus acanthias in the Northeast U.S. Continental Shelf Large Marine Ecosystem (NES LME). Diel catch-per-unit-effort (CPUE) estimates are examined from the Northeast Fisheries Science Center bottom trawl surveys conducted during autumn (1963–2009) and spring (1968–2009). Influential environmental variables on survey catchability are identified for Spiny Dogfish life history stages and five pelagic prey species: Butterfish Peprilus triacanthus, Atlantic Herring Clupea harengus, shortfin squid Illex spp., longfin squid Doryteuthis spp., and Atlantic Mackerel Scomber scombrus. Daytime survey catchability was significantly higher than nighttime catchability for most species during autumn and for mature male Spiny Dogfish, shortfin squid, and longfin squid during spring in the NES LME. For most stages and species examined, breakpoint analyses identified significant increases in CPUE in the morning, peak CPUE during the day, and significant declines in CPUE in the late afternoon. Seasonal probabilities of daytime catch were largely driven by solar zenith angle for most species, with stronger trends identified during autumn. Unadjusted CPUE estimates appear to overestimate absolute abundance, with adjustments resulting in reductions in absolute abundance ranging from 41% for Spiny Dogfish to 91% for shortfin and longfin squids. These findings have important implications for Spiny Dogfish regarding estimates of population consumption of key pelagic prey species and their ecological footprint within the NES LME.

Factors Influencing Daily Growth in Young-of-the-Year Winter Flounder along an Urban Gradient Revealed Using Hierarchical Linear Models

Abstract Growth during early life history plays a key role in the recruitment dynamics of marine fishes; however, the effects of environmental stressors on growth are often difficult to quantify. In this study, increment widths from sagittal otoliths were used as a proxy for daily growth in 102 young-of-the-year Winter Flounder Pseudopleuronectes americanus collected over a 2-year period from three sites in Long Island, New York. We hypothesized that we would observe different growth patterns among bays due to an environmental gradient driven primarily by contaminant loadings and environmental stressors in our study sites. Hierarchical linear models were utilized to associate individual attributes (ontogeny, condition, and gene expression) to daily growth patterns during each year. As expected, daily growth generally displayed a negative relationship with age and daily average temperature, although the effect of temperature was much more variable. Out of 14 individual attributes, the settlement date, the age at capture, the condition indices Fultons K and hepatosomatic index, and the expression of genes associated with immune response (pleurocidin), contaminant exposure (cytochrome P5401A), and glucose and glycogen metabolism (glycerol-3-phosphate dehydrogenase) were observed to significantly and consistently affect growth. The results provide evidence of differential growth based on the date of settlement and condition, and the molecular indicators of stress suggest that growth is also influenced by habitat quality. There were significantly different relationships between individual attributes and growth among bays, but these did not always reflect the proposed environmental gradient. Together, the results suggest that anthropogenic stressors likely play a role in growth and recruitment processes in Long Island bays and indicate that growth is both spatially and temporally dynamic at multiple scales. Furthermore, this study highlights the utility of hierarchical linear models in analyzing complex daily growth data in juvenile fish, which may be applicable to other species.

Diel Behavior in White Perch Revealed using Acoustic Telemetry

AbstractAcoustic telemetry was used to investigate small-scale movement and behavior of semi-anadromous White Perch Morone americana in New Yorks Great South Bay system. Fifteen Vemco VR2 acoustic receivers were deployed in the main channel of the lower Carmans River. Of the 40 fish that were tagged with Vemco V9 acoustic transmitters from August 2010 to 2011, 15 fish returned at least 28 d of movement data. Acoustic tracking revealed that adult White Perch exhibited upstream and downstream diel movement within the Carmans River, a behavior that has not been previously described in adults of this species. Movements were tested for cyclical patterns by using autocorrelation analysis. The frequency of diel behavior (f) across individuals was found to be dependent on season: frequency was significantly reduced in winter (f = 13.8%) and was maximized in summer (f = 49.4% in 2010; f = 57.5% in 2011). Directionality in diel movement was also seasonal; nightly upstream movements were favored in summer and fall ...

Response of mollusc assemblages to climate variability and anthropogenic activities: a 4000-year record from a shallow bar-built lagoon system.

With their position at the interface between land and ocean and their fragile nature, lagoons are sensitive to environmental change, and it is reasonable to expect these changes would be recorded in well-preserved taxa such as molluscs. To test this, the 4000-year history of molluscs in Great South Bay, a bar-built lagoon, was reconstructed from 24 vibracores. Using x-radiography to identify shell layers, faunal counts, shell condition, organic content, and sediment type were measured in 325 samples. Sample age was estimated by interpolating 40 radiocarbon dates. K-means cluster analysis identified three molluscan assemblages, corresponding to sand-associated and mud-associated groups, and the third associated with inlet areas. Redundancy and regression tree analyses indicated that significant transitions from the sand-associated to mud-associated assemblage occurred over large portions of the bay about 650 and 294 years bp. The first date corresponds to the transition from the Medieval Warm Period to the Little Ice Age; this change in climate reduced the frequency of strong storms, likely leading to reduced barrier island breaching, greater bay enclosure, and fine-grained sediment accumulation. The second date marks the initiation of clear cutting by European settlers, an activity that would have increased runoff of fine-grained material. The occurrence of the inlet assemblage in the western and eastern ends of the bay is consistent with a history of inlets in these areas, even though prior to Hurricane Sandy in 2012, no inlet was present in the eastern bay in almost 200 years. The mud dominant, Mulinia lateralis, is a bivalve often associated with environmental disturbances. Its increased frequency over the past 300 years suggests that disturbances are more common in the bay than in the past. Management activities maintaining the current barrier island state may be contributing to the sand-mud transition and to the bays susceptibility to disturbances.

The influence of temperature stress on the physiology of the Atlantic surfclam, Spisula solidissima

Atlantic surfclam populations have significantly declined in state and federal waters from the south shore of Long Island, New York to the Delmarva Peninsula since the early 2000s. Previous studies have demonstrated that surfclams in this geographic range show signs of physiological stress, suggested to be a result of increasing ocean temperatures. In this study, we examined the effect of 2 temperature regimes (19 °C and 23 °C) on surfclam physiology. These temperatures were chosen because they represent maximal (23 °C) and minimal (19 °C) temperatures prevailing in New York clamming areas during summer. Results demonstrated enhanced energy metabolism and significant reductions in filtration rate, scope for growth, and immune functions in clams exposed to the warmer temperature treatment. Although net energy gains remained positive in both treatments under our experimental conditions, the findings suggest that temperature stress is involved in the recent observations of surfclams in poor condition. The impact of elevated temperatures on phytoplankton quantity/quality and other environmental variables in combination with the direct impact on surfclam filtration and metabolic rates could lead to a negative energy balance. While some uncertainties remain about population-scale impacts of overall warming trends, we fear that future increases in temperature may lead to the collapse of the Atlantic surfclam between New York and Virginia, especially within inshore regions.