Stomach contents of striped bass (Morone saxatilis) collected from three coastal regions of Massachusetts during JuneSeptember in 19972000 were examined for patterns in prey composition and body size related to coastal region, time period of capture, foraging habitat, and length of striped bass. Together fish (mostly Clupeidae, Menidia sp., and Ammodytes sp.) and crustaceans (mostly Crangon septemspinosa, Cancer irroratus, and Homarus americanus) dominated the diet of striped bass by both weight (9195%) and number (8797%), and had a high frequency of occurrence (4266%) in the stomachs. Similarity in prey taxa among coastal regions was moderate to high (5874%). Cluster analysis and ordination techniques grouped the stomach contents from each region by capture period, habitat, and 50 mm striped bass length interval. The stomach contents of bass <675 mm total length (TL) collected during August September from estuaries and rocky shoreline habitats in the North Shore and Cape Cod Bay regions had a higher average percentage of menhaden (Brevoortia tyrannus) by weight than found in similar-sized bass collected during JuneJuly from the same habitats. Also, in the North Shore area, striped bass <675 mm TL sampled in rocky shorelines contained a higher average percentage of Cancer irroratus by weight than similar-sized bass taken in estuaries. Bass >675 mm TL in rocky habitats consumed more Homarus americanus than smaller bass residing in this same habitat. The size distribution of the dominant fishes and crabs (Ammodytes sp., B. tyrannus, Cancer irroratus, and Carcinus maenus) consumed by striped bass was related to bass body size. Benthic prey were found to be a major component of the diet of striped bass in Massachusetts coastal waters.

The spatial and temporal distribution patterns of the Atlantic wolffish (Anarhichas lupus) from the Gulf of Maine-Georges Bank region were examined based on bottom trawl survey data from 1963 to 1989. Age composition, growth and food habits were also evaluated from 1983 to 1989. Catches of wolffish were distributed throughout the region, but highest concentrations occurred along the 100 m depth contour of the Gulf of Maine-Georges Bank.Statistical analyses of the depth occurrences revealed a seasonal shift in depth distribution from shallow water (<120 m) in spring to deeper water in autumn. Further analyses showed that the large (>50 cm) wolffish migrate to these shallow waters in spring and return to deeper waters in autumn.The oldest wolffish aged was 22 years. Mean length-at-age ranged from 4.7 cm total length for age 0 to 98.0 cm total length for age 22 in spring. Growth was modelled best by the Gompertz function. Bivalve molluscs (primarily Placopecten magellanicus) dominated the diet, followed by echinoderms, gastropods and decapods.

Seasonal, age-class, and population-level changes in diet and consumption demand of prey by striped bass residing in coastal waters of northern Massachusetts were investigated to determine their potential predatory impact on ecologically-and economically-important prey species. Most consumption by individual striped bass of ages 3-8 came from crustaceans and fish. More crustaceans (50-78% of total consumption) than fish were consumed during June-July, while more fish (52-88% of total consumption) than crustaceans were consumed during August-September. Rock crabs Cancer irroratus and American lobsters Homarus americanus became more important to the production of striped bass as bass aged, but Atlantic menhaden Brevoortia tyrannus became less important. Together, the biomass of prey consumed by all age-classes in 2000 totaled over 5 575 t. Atlantic menhaden accounted for 29% of the total biomass consumed, followed by rock crabs (18%), American lobster (11%), and Atlantic herring Clupea harengus (3%). On a numerical basis, striped bass consumed seasonally over 3, 1 940, and 965 times the numbers of lobsters, rock crabs, and menhaden, respectively, taken annually by regional and statewide fisheries, suggesting striped bass may exert considerable predation pressure on these prey populations.

Trends in temporal and spatial abundance, and population size structure of the sand lance,

Cluster sampling is a common survey design used pervasively in fisheries research to sample fish populations, but it is not widely recognized by researchers. Because fish collected via cluster sampling are not independent of each other, standard simple random sampling estimators and statistical tests that assume independence cannot be used to make inferences about fish populations. If the clustered nature of fisheries data is ignored, the main consequence is that the type I error rate of common statistical tests will be severely inflated and significant differences will often be found in group comparisons where none exist. The goal of this paper is to provide an introduction to the estimation of population attributes and analysis of fisheries data collected via cluster sampling. This article addresses the nature of clustered fisheries data, reviews the random cluster sampling estimators of population attributes, explores the implications of violating the assumption of independence in hypothesis testing, and reviews current statistical approaches that can be used to analyze appropriately clustered data. Received November 8, 2013; accepted February 27, 2014