Saul B. Saila

Prevalence of neoplasia in 10 New England populations of the soft-shell clam (Mya arenaria).

Neoplasia was a prevalent disease of the soft-shell clam and was found in widely geographically distinct sites in New England. Two types of neoplasms were recognized. Most were of hematopoietic origin, except in clams from Maine, which also had gonadal neoplasms. Both types were apparently malignant neoplasms, based on their characteristic anaplastic appearance, invasiveness, metastasis, mitotic activity, associated tissue necrosis, and mortality. Diagnosis of neoplasia in the living mollusk was achieved rapidly and accurately by cytologic examination of circulating blood. The etiology of the neoplasms was not identified. In general, nonneoplastic lesions, such as epithelial hyperplasia and accumulations of a orange-brown bodies, were more common in clams from polluted areas.

A Method for Determining Mortality Rates Using the Leslie Matrix

Abstract The Leslie matrix algorithm has been utilized to estimate mortality of a year class assuming an equilibrium population for a species. Under this assumption an estimate of the mortality for the 0th year class of the Atlantic bluefin tuna (Thunnus thynnus thynnus) has been made indicating about five survivors from 10 million eggs in the first year of life. The mortality rates for later year classes were derived from empirical data.

Does Lobster Trap Bait Influence the Maine Inshore Trap Fishery

Abstract The potential role of lobster trap bait as a significant food subsidy contributing to unprecedented recent increases in abundance and landings of the American lobster Homarus americanus is seldom considered seriously outside the fishing community. Although bait input is a very small source of organic carbon compared with primary production, the yearly input of bait per unit area to the inshore waters of the Gulf of Maine is about 85 kg/ha, an amount equal to a very productive fishery yield from a marine area. Because much of the bait is imported from outside the inshore area of the Gulf of Maine, it represents a direct subsidy to secondary production within this portion of the system. An empirical relationship between fish yield and primary production in phytoplankton-based marine systems suggests that inshore primary production would have to be increased by about 80% to provide an increment in fish yield equal to the bait input. Moreover, a simple trophic calculation based on an estimated amount...

Optimum allocation strategies for sampling benthos in the New York Bight

Abstract Sampling plans based on historical data available from the Marine Ecosystems Analysis (MESA) New York Bight Project are described and illustrated. These plans are efficient in the sense that they provide the requisite levels of precision for the minimum expenditure of time and effort. Sampling for a single variable (selected trace elements) is optimized directly. Sampling for several variables simultaneously in a two-stage scheme can also be optimized. The optimization procedure is explained and illustrated in detail and the results for a realistic case are given. Relatively few replicates (approximately five) are shown to be required to test reasonably defined hypothesis concerning differences in trace elements between two stations. It is also shown that an optimum two-stage sampling plan for Cerianthus americanus involved relatively few replicates within a station (3) and a fairly small number of stations (7) in order to satisfy derived variance and cost constraints for the New York Bight with an acceptable level of confidence (90%) for 50% differences in abundance of transformed mean values. Sample sizes for six other species were also determined and a compromising allocation is discussed.

Correlations Between Alewife Activity and Environmental Variables at a Fishway

Abstract An automatic recording system for fish counting and for the monitoring of water temperature, dissolved oxygen, pH and solar radiation was employed on a newly constructed fishway on the Annaquatucket River, North Kingstown, Rhode Island. Records of fishway utilization by the alewife, Alosa pseudoharengus and of the environmental variables were critically examined by time series autocorrelation and crosscorrelation techniques. It was demonstrated that migratory activity was harmonic with a diurnal periodicity and was closely associated with incident solar radiation. Suggestions for an improved monitoring system and further analysis were made.

Oil-spill fishery impact assessment model: Application to selected Georges Bank fish species

Abstract An oil-spill fishery impact assessment model composed of an oil-spill fates model, a shelf hydrodynamics model, an ichthyoplankton transport and fate model, and a fishery population model originally developed by Reed & Spaulding, has been improved and applied to the Georges Bank-Gulf of Maine region to assess the probable impact of oil spills on several key fisheries. The model addresses direct impacts of oil on the commercial fishery through hydrocarbon-induced egg and larval mortality. This early life stage hydrocarbon-induced mortality is estimated by assuming a toxicity threshold approach and by mapping the spatial/temporal interaction between the subsurface oil concentrations caused by the spill and the developing eggs and larvae. Model output is given in terms of differential catch, with a comparison made of hydrocarbon-impacted fisheries. Simulations of tanker and blowout spills at two separate locations for each season of the year in the Outer Continental Shelf lease areas have been completed for Atlantic herring, haddock, and Atlantic cod. Results to date suggest a complex interaction among spill location and timing, the spatial and temporal spawning distribution of the species, and the hydrodynamics of the area. The largest impacts occur for spring and winter spills.

Oil spill fishery impact assessment modeling: the fisheries recruitment problem

Abstract A model to assess the impact of oil spill on fisheries, consisting of an oil spill fates model, a continental shelf hydrodynamics model, an ichthyoplankton transport and fates model, and a fish population model, has been applied to the Georges Bank-Gulf of Maine region to estimate the impact of oil spills on several important commercial fisheries. The model addresses direct impacts of oil on a fishery through hydrocarbon-induced egg and larval mortality. This early life stage mortality is estimated by dynamically mapping the spatial intersection of the surface and subsurface oil concentrations resulting from the spill with the developing eggs and larvae. Ichthyoplankton entering an area with hydrocarbon concentrations in excess of a specified threshold are assumed lost. Model output is given in terms of differential catch, comparing the non-impacted and the hydrocarbon impacted fisheries. Difficulties in establishing stock-recruit relationships, and the inability to predict first year survival even one year ahead make the quantification of absolute catch losses impossible. Output of the model system discussed here is therefore limited to relative rather than absolute catch losses. The paper is organized to demonstrate first the importance of the recruitment question to impact estimation, second that a modeling methodology is necessary to evaluate impacts given the magnitude of unexplained observed recruitment variability, and third a stochastic solution to the problem which places impact estimates in the context of a probability distribution. Lastly, the model system is applied to the problem of attaining better early life history mortality estimates, to ultimately improve impact estimation capabilities.

A comparison of the incidence of five pathological conditions in soft-shell clams, Mya arenaria, from environments with various pollution histories

Abstract The distribution of the occurrences and co-occurrences of five pathological conditions in samples of the soft-shell clam, Mya arenaria, from 17 locations on the east coast of the United States were compared by two different analytical techniques. 1. The relative fit of Poisson and Lagrange-Poisson distributions to the data were related to the mortality rate and spread of the pathological conditions. 2. A severity index based on a matrix of occurrences and co-occurrences, and the analysis of its eigenvectors were used to measure and to characterise the severity of the spread. These two techniques were compared with the help of a cluster analysis and discussed in the context of the pollution history of the seventeen locations studied. Although causal inferences cannot be drawn, the analyses suggested that crude oils and heavy metals had less effect on the incidence of hyperplasia and neoplasia than more refined petrochemicals. However, neoplasia was found in both clean and polluted environments.

Equivalent Adult Estimates for Losses of Fish Eggs, Larvae, and Juveniles at Seabrook Station with Use of Fuzzy Logic to Represent Parametric Uncertainty

Abstract Regulatory agencies continue to direct their attention to the impact of coastal power generating stations on fishery resources. We analyzed 6 years of entrainment and 2 years of impingement data for selected species at the Seabrook Station, Seabrook, New Hampshire, in combination with selected life history parameters to provide equivalent adult estimates of fish losses at the station. The species examined were the winter flounder Pleuronectes americanus pollock Pollachius virens, and red hake Urophycis chuss. The standard equivalent adult method involves estimates of numbers of fish entrained and impinged, survival from egg to impacted life history stage, and the average lifetime fecundity of a newly recruited female. However, this method does not account for the uncertainty in model parameters. The method was extended by applying fuzzy arithmetic to fuzzy numbers constructed from empirical data to provide upper and lower bounds on the estimated losses as equivalent adults. The analyses indicated...

A statistical technique for analysis of environmental data containing periodic variance components

A statistical technique for analyzing data containing periodic variance components when the observations are made at irregular intervals is described. The technique uses a less constrained version of harmonic or periodic regression than that usually employed. The main feature of this method is that a known period is hypothesized, and its component is removed from the data if it is found to be significant. This is in contrast to searching for the presence of unknown periodic components following a classic Fourier analysis. For environmental monitoring programs, biological rhythms may create special problems in estimating average abundances present at one or more stations sampled at different times. Correct interpretations of this type of sampling data become even more difficult when time series data is obtained at irregular intervals, and the objective is trend monitoring for environmental disturbances. The steps in the analysis are described in detail, and the new method of analysis is applied to the abundance of a marine flatfish captured at the intake of a coastal power plant.