Catherine A. Kuropat

Effect of cadmium accumulation on serum vitellogenin levels and hepatosomatic and gonadosomatic indices of winter flounder (Pleuronectes americanus)

Vitellogenin (Vg) is an egg yolk precursor protein that is produced in the liver and transported to developing oocytes in the gonad by the blood. Contaminants in the environment may affect its production by the liver as well as its uptake by the gonad, threatening the development and survival of winter flounder embryos or larvae. In order to study the effects of cadmium contamination on serum Vg levels (measured as alkali-labile phosphate or ALP), female winter flounder were exposed to 25 or 50 μg/L cadmium in seawater for 71 days. The exposure began in early November when Vg production begins, and ended in mid-January, when Vg levels peak.At the end of the exposure period, blood samples were taken from each fish, refrigerated, and allowed to clot overnight. The sera were collected by centrifugation the following day and frozen. Weights of the liver, both gonads, and the entire fish were recorded for later calculation of hepatosomatic (HSI) and gonadosomatic indices (GSI), respectively. Liver samples were also taken for measurement of cadmium levels.Serum ALP levels rose with increasing HSI. Both HSI and ALP decreased with increasing cadmium concentration in the liver. Lower serum Vg may result in lower fecundities for the adults and smaller yolk sacs for the larvae reducing the overall reproductive success of the winter flounder population.

The effects of fin rot disease and sampling method on blood chemistry and hematocrit measurements of winter flounder, Pseudopleuronectes americanus from New Haven Harbor (1987--1990).

Winter flounder from New Haven, Connecticut were evaluated for fin rot disease. Blood samples collected from healthy and diseased fish were used to measure bilirubin, calcium, hematocrit, inorganic phosphorus, osmolality, and total protein. Blood measurements were significantly affected by the presence of fin rot disease and by sampling mode (bled immediately or after 18 h). A reduction in blood chemistry values was associated with fin rot disease. Logistic regression modeling was used to identify explanatory variables contributing to the fin rot outcome in winter flounder. Blood constituent levels were higher in fish bled immediately versus 18 h post-capture, especially among fish without fin rot, suggesting that a waiting period is necessary for blood values to stabilize following initial sampling stress. This study presents evidence that winter flounder blood chemistry and hematocrit measurements are affected by fin rot disease.

Growth of Juvenile Scup, Stenotomus chrysops, Fed Three Commercial Diets

Juvenile scup, Stenotomus chrysops, 0.5–1.5 g weight were fed three different commercial diets for six weeks to determine growth rates. Diets were hand-distributed to triplicate groups of 30 fish, four times a day. Survival for all treatments was 93%. The diets used were INVE Aquaculture NRD marine diet (NRD), Skretting Feed Products Gemma starter feed (Gemma), and Salt Creek Progression fish starter diet (Progression). While all diets supported good growth, after 6 weeks scup fed the NRD diet were of significantly greater length and weight (P < 0.05) than fish fed the other diets. The effects of each diet on fish growth were significantly different from each other (P < 0.05), with final live weight (g), total length (mm), relative growth rate (RGR), and daily weight gain (DWG) measurements higher for fish fed the NRD diet. Scup fed the Gemma diet were of significantly greater length and weight than fish fed the Progression diet. The specific growth rate (SGR) of scup fed either the NRD or Gemma diets were not significantly different; however, both of these diets produced fish with significantly higher SGR than those fed the Progression diet. Feed conversion ratios (FCR) of scup fed either the NRD or the Gemma diets were significantly lower than the FCR of fish fed the Progression diet. SGR values were 6.6%, 6.3% and 5.6%/day, and FCR values were 1.03, 1.11, and 1.31 for fish fed the NRD, Gemma, and Progression diets, respectively. RGR values were 1,439%, 1,212%, and 895%, and DWG values were 0.33 g, 0.27 g, and 0.20 g/day for scup fed the NRD, Gemma, and Progression diets, respectively.

Observations of Juvenile Lobsters, Homarus americanus, on a Rock-Reef in Long Island Sound

Abstract Movements of juvenile Homarus americanus (American Lobster; hereafter lobster) on and around a naturally occurring rock reef were monitored over a 3-year period. Lobsters were sampled with baited traps deployed at each often sites. Catch-per-unit-effort (CPUE) and number of lobsters collected per trap haul was calculated for each sampling event. Physical habitat, visually characterized by underwater video and diver observations, differed among sites. Lobster CPUE was significantly greater at rocky sites (>70% density of cobble and/or boulder) containing complex structure, vertical relief from the seafloor, and colonies of macroalgae, sponge, and hydroids. Lobster CPUE was highest from late June to mid-July. Lobsters ranged from 18 to 82 mm carapace length (CL), with 90.7% of tagged lobsters measuring between 30 to 60 mm CL. Relative lobster abundance remained similar over the course of the study. Catch data were kriged to illustrate spatial patterns of distribution. Over the study period, a total of 934 lobsters were tagged and 66 were recaptured, for an overall recapture rate of 7.1%. The majority of recaptured animals (88%) were found at the original tagging site or adjacent sites, with one lobster remaining at liberty for 397 days. Most juvenile lobsters showed fidelity to their initial site of capture on a small, relatively isolated patch of rock-reef habitat in the central basin of Long Island Sound.

Benthic Ecology of Northern Quahog Beds with Different Hydraulic Dredging Histories in Long Island Sound

ABSTRACT Mercaldo-Allen, R.; Goldberg, R.; Clark, P.; Kuropat, C.; Meseck, S.L., and Rose, J.M., 2016. Benthic ecology of northern quahog beds with different hydraulic dredging histories in Long Island Sound. This paper evaluates benthic community composition of four shellfish beds in Long Island Sound near Milford, Connecticut, where northern quahog or hard clams, Mercenaria mercenaria (Linnaeus 1758), were harvested by hydraulic dredge. These leased beds reflect a variety of dredging histories; 0 year (dredged just before sampling began), 1 year postharvest, 2 years postharvest, and an inactive clam bed left fallow for at least 10 years. Benthic sediment was sampled at 1- to 2-week intervals from June to October 2011 using a Smith–McIntyre grab. Benthic community composition was significantly influenced by dredging history and sampling month. Abundance of benthic organisms (number of individuals and biovolume) and total organic matter concentrations were significantly greater at the 0-year site than at the 1-, 2-, and 10+-year sites, and significantly greater at the 1- and 2-year sites than at the 10+-site. Newly settled bivalves, primarily Nucula spp. and Yoldia limulata, were significantly more prevalent on the recently harvested 0-, 1-, and 2-year sites vs. the 10+-year site and highest at the 0-year site. A significantly greater number of species was observed on the 1- and 2-year sites vs. the 0- and 10+-year locations. Species richness at the 0-year site was significantly lower than at the 1-, 2-, and 10+-year sites, whereas diversity and evenness at the 0-year site was significantly lower than at the 10+-year site. This study observed successional changes in community structure of inshore clam beds related to the length of time elapsed after harvest dredging.

Correction to: Effects of clam dredging on benthic ecology of two cultivated northern quahog beds with different harvest histories and sediment grain sizes

The original version of this article unfortunately contained an error where the symbol for phi size was inadvertently omitted from the text.

A Field-Based Nursery for Headstarting Lobsters to Improve Postrelease Survival for Potential Stock Enhancement in Long Island Sound, Connecticut

AbstractEarly benthic stage American lobsters Homarus americanus were held in a pilot nursery system in Long Island Sound (LIS), Connecticut, to test field grow out as a step toward potential stock enhancement. A larger size upon release may increase the probability of survival. Lobsters were placed individually in perforated plastic mesh cylindrical “habitats,” and each habitat was housed in an outer protective sleeve with a larger mesh size. During June 2013, 24 lobsters were transferred to each of three wire mesh cages and deployed southwest of Charles Island in Milford, Connecticut (N = 3). The only source of nutrition was naturally occurring organisms. Cages were retrieved monthly, and lobsters were photographed to measure changes in carapace length (CL). After 11 months in the field, lobsters increased 92% in mean size from 6.0- to 11.6-mm CL, with 70.8% overall survival. Headstarting of early benthic stage lobsters shows promise as a tool for possible future stock enhancement in LIS.Received August...