Performance Report for Cooperative Agreement No: na06oar4810163 for the Period from September 1, 2006 to August 31, 2012 University of Maryland Eastern Shore

In order to conduct the feed study, 184 striped bass (average weight =154 g) were transported to the NOAA Cooperative Oxford Laboratory. These fish have been placed on two diets; a basal striped bass commercial feed and a diet formulated to be low in PUFA by replacing marine oils with olive oil. Each dietary treatment will either receive an injection of M. marinum on Sept. 15, 2008 or a sham injection. One week prior to injection 2 fish/tank will be sampled to determine initial (T₀₎ immune activity (phagocytic and leukotriene production potential) and fatty acid composition.

The protocols for fatty acid analysis and immune function were adapted to this project utilizing 16 striped bass obtained from Horn Point Laboratory (Cambridge, MD). Fatty acid analysis was conducted at NOAA CCBHER (Charleston, SC) under the guidance of Gloria Seaborn. The 16 striped bass, which had been feeding on a commercial feed (Melick Aqaufeed) during their life cycle, showed significant amounts of variability in their fatty acid composition; the lowest levels of variability were found in the fatty acid species arachadonic acid (20:4 n-6), ecosapentaneoic acid (20:5 n-3), and decosapentaenoic acid (22:6 n-3).

Total leukocytes from Horn Point striped bass (n=12) were analyzed for their ability to phagocytize both opsonized and non-opsonized FITC-labeled yeast. Production of leukotriene B₄ (LtB₄) by these same leukocytes was also determined using a commercial LtB₄ kit (Cayman Chemical) following stimulation with 10 uM calcium ionophore. LtB₄ production by the cells was below the range of the assay when the cell supernatants were diluted 1:5; purification of the supernatants using Sep-Pak C18 cartridges will be conducted in order to obtain an accurate measurement of LtB₄.

During Year 2 of this grant, the investigators have progressed through: 1) Continued extraction of data from images of young fish from Year-1 experimental rearing, and synthesized data on developmental rates, resistance of larvae to starvation, and survival, 2) Refinement of the experimental protocol which allows for repeated exposures of larvae to PCBs, 3) Implementation of a more robust experimental design with more life stage-specific rearing options and a greater replication of experimental replication, 4) Exposure of embryos from a reference (Shinnecock Bay, NY) and an impacted (Hudson River) population of Atlantic tomcod to graded doses of two PAHs (DMBA and DBP) and two doses of Aroclor mixture of PCBs. Larvae that survived exposures as embryos were subsequently exposed 10 times over a 5-week period to either a low or high dose of Aroclor through their food source (Artemia). This has resulted in a large, factorial design of 7 PAH levels (including controls) × 3 PCB levels (with controls). This design was replicated four times while fish were in the static rearing phase (embryos, pre-feeding larvae, and feeding larvae which were exposed through their food source), and was collapsed to two replicates during subsequent rear-out phase in flow-through tanks. Juveniles were then marked with subcutaneous elastomer tags, pooled into larger tanks, and are currently being reared to reproductive maturation, 5) Synthesis of data already in hand from Year 2, 6) Preparation of total RNA from tomcod ovary and liver samples and analysis of same qualitatively and quantitatively using spectroscopic and experion automated electrophoresis platform from Biorad (this information will be used to obtain cDNA sequences using degenerate primers), and 7) Development of protocols and evaluation of the gene encoding the ovarian aromatase enzyme (cyp19a) as biomarker to assess reproductive stress. A model fish species was required that could be spawned during any season of the year in order to quickly develop this technique. To this end, the Atlantic killifish (Fundulus heteroclitus) was chosen as a model and quantitative real time PCR laboratory procedures were developed to assess the effect of exposure to aryl hydrocarbon receptor (AHR) ligands benzo[a]pyrene (a polyaromatic hydrocarbon, PAH) and PCB-77 (a polychlorinated biphenyl congener) on the expression of genes relevant to the AHR mediated toxicity pathway. It was found that PCB-77 significantly increased AHR1 mRNA levels whereas B[a]P significantly increased ARNT2 mRNA levels. BaP treatment has significant effect on arnt2 expression levels as compared to the control.

Monkfish is the highest valued finfish in the Northwest Atlantic, yet aspects of its biology remain poorly understood. Monkfish fishermen in the US assert that temperature plays a key role in the distribution of monkfish and in the timing of onshore migration in the spring. If temperature is an important controlling factor in monkfish behavior, shifts in distribution of monkfish may have occurred in recent years. Since little is known of temperature-related behavior of American monkfish, Lophius americanus, it was proposed to determine the influence of temperature on the distribution of monkfish in the northwest Atlantic and examine the role of temperature in triggering migration in spring (onshore) and fall (offshore). In addition, the study was aimed at determining the reproductive stage of migrating monkfish to address questions related to location and timing of spawning.

Since January 2008, data have been obtained from the NEFSC and Canadian trawl surveys spanning 1948 to 2007. These data are currently being analyzed. Temperature probes were purchased and distributed to 8 industry collaborators who collected temperature and depth data during the spring 2008 fishing season.

Other sources of survey data for monkfish including catch rates, bottom temperature, and depth data that were acquired from the Canadian Department of Fisheries and Oceans. Canadian bottom trawl surveys were conducted on the shelf of Nova Scotia and the Bay of Fundy during the summer (1950’s, 1970 to 2007), spring (1978 to 1984; 1986 to 2007), fall (1978 to 1984 on the Eastern Scotian Shelf), and fall (1978 to 1984) and Georges Bank during winter (1987 to 2007). Canadian trawl surveys use a stratified random design with strata defined by fish biogeography and depth. At each station, sampling includes identifying the entire catch to the species level as well as enumerating, weighing, and measuring each species caught. Oceanographic data including temperature, salinity, and depth were also recorded at each station.

The link between precipitation and ingress of larval American eel has been reported by others for decadal work (Sullivan et al. 2006), and may be explained by discharge of odorants into coastal estuaries (Sorensen 1986). No studies have documented the intra-seasonal correlations between precipitation and ingress of American eel. Local effects of stream discharge and precipitation can affect recruitment patterns of American eel. As precipitation and stream discharge patterns vary because of climate change, recruitment of American eel may be dramatically affected, and therefore affect the commercial harvest of this species. A method to stage larval American eel by quantifying its pigment, and analyzing the pigment’s relationship to the environment was developed from this project. Size corrected pigment level for the average of all 4 studied areas on the American eel body differed among sites. Pigment level differed among sites perhaps because of temperature differences. Warmer temperatures were associated with greater levels of body pigment; this relationship was not related to growth throughout spring and summer because pigment levels were size-corrected using residuals of length-pigment regressions.

How will results be incorporated into NOAA Fisheries operations?

During the progress period, the graduate student successfully defended a thesis entitled, Early life history of American eels (Anguilla rostrata) in the coastal lagoons of Maryland. The thesis was published and is housed within the Frederick Douglas Library at the University of Maryland Eastern Shore. The graduate student and his advisor, Joseph W. Love, are currently preparing a manuscript of the research entitled, “Distribution and pigmentation patterns of glass eels (Anguilla rostrata Lesueur) in a coastal lagoon.” This manuscript is also co-authored with Dr. Gretchen Bath-Martin (NOAA Beaufort Laboratory, NC).

To date, over 450 scales from individual fish have been collected and stored. The scales have been digitally imaged and will soon be analyzed for growth patterns. In addition to the growth work, approximately 850 fish have been marked using subdermal tags or fin clipping. This effort has been made to determine the level to which fish move among habitats within the system, but also to measure individual growth and estimate population sizes. We are currently sampling to recapture tagged individuals.

There was a positive relationship between length and mass for juvenile white perch. After calculating Fulton’s condition factor (a ratio of mass to length), it was observed that body condition was significantly higher in freshwater than brackish water. In general, salinity, dissolved oxygen, and temperature influenced condition of juvenile white perch. While condition was lower when salinity was high, condition was highest when dissolved oxygen and temperature were higher. These results suggest that freshwater habitats are important nurseries for semi-anadromous species, and therefore need to be maintained.

While some analyses are underway, the major findings of the research are: 1) juvenile white perch are in better condition and grow relatively faster in freshwater than brackish water, supporting the importance of freshwater as nursery habitat for contingents of this semi-anadromous fish; 2) movement among habitats is low for young-of-year; and 3) diets of white perch differ between freshwater and brackish habitats, with more terrestrial insect fauna and less detritus consumed in freshwater environments.