Macroinfauna of northern New England marine sand. III. The ecology of Psammonyx nobilis (Stimpson), 1853 (Crustacea: Amphipoda)

1976 ◽  
Vol 54 (9) ◽  
pp. 1519-1529 ◽  
Author(s):  
K. J. Scott ◽  
R. A. Croker
Keyword(s):  
New England ◽  
Fine Sand ◽  
Early Spring ◽  
Breeding Period ◽  
Sexually Dimorphic ◽  
Organic Debris ◽  
Marine Sand ◽  
Shallow Subtidal ◽  
Northern New England ◽  
Intertidal Habitats

The boreal lysianassid Psammonyx nobilis is associated with very well sorted, fine sand of low intertidal and shallow subtidal habitats. It is a winter to early spring breeder, with recruitment from June to August in New England. Females produce up to 50 eggs and have one brood per breeding period. Generation time is 2 years. Larger adults occur only during colder months at more exposed intertidal habitats, while all life stages occur at sheltered intertidal habitats throughout the year. Females are larger than males and are more abundant at the landward periphery of intertidal populations. Subtidal populations show smaller adults and juveniles present most of the year. The species is a scavenger–omnivore exhibiting an aggregated pattern of distribution. Swimming activity is highest in the dark during falling tides. Respiration increases significantly at salinities < 20‰. The length of pereopod 7 was the sole sexually dimorphic character observed. The heretofore enigmatic, elongate gnathopod 2 is not used in precopula, but for removing organic debris from the thoracic cavity.

Macroinfauna of Northern New England marine sand. IV. Infaunal ecology of Amphiporeia virginiana Shoemaker, 1933 (Crustacea: Amphipoda)

1979 ◽  
Vol 57 (8) ◽  
pp. 1511-1519 ◽  
Author(s):  
Richard P. Hager ◽  
Robert A. Croker
Keyword(s):  
South Carolina ◽  
New England ◽  
Late Summer ◽  
Fine Sand ◽  
High Energy ◽  
Breeding Period ◽  
Population Fluctuations ◽  
Marine Sand ◽  
Annual Population ◽  
Early Fall

Amphiporeia virginiana occurs from Nova Scotia to South Carolina where it is a dominant inhabitant of high energy sand beaches. Maximum abundance occurs on the lower foreshore in fine sand particularly during summer months. Within-habitat segregation of sexes occurs, with females more abundant at higher beach levels; ovigerous females are confined to higher levels only. Annual population fluctuations of up to 14-fold on a geometric basis are related to life history events and sedimentary changes. Breeding occurs during most of the year with peak recruitment during June and late summer to early fall, yielding summer and overwintering generations. Precopulating animals are commonly seen swimming, with two males per female occasionally evident. Females produce a mean of 6–11 eggs during the year and have one brood per breeding period. The species is a detritivore and generally inhabits the upper 2.5 cm of sand. It is most tolerant of salinities in the range of 25–35‰; mortality increases rapidly in salinities less than 20‰, and in sediments containing less than 11% water by weight exposed to temperatures simulating hot summer days.

Macroinfauna of northern New England marine sand. II. Amphipod-dominated intertidal communities

1975 ◽  
Vol 53 (1) ◽  
pp. 42-51 ◽  
Author(s):  
R. A. Croker ◽  
R. P. Hager ◽  
K. J. Scott
Keyword(s):  
New England ◽  
Atlantic Coast ◽  
Dry Weight ◽  
Amphipod Species ◽  
Species Dominance ◽  
Carbon And Nitrogen ◽  
Marine Sand ◽  
Nitrogen Concentrations ◽  
Northern New England ◽  
Exposed Habitat

This is a 5-year study of macroinfaunal communities of moderately exposed to sheltered intertidal sands of New Hampshire and southwestern Maine. Habitats also differed in slope, width, predominant sand grain size, and carbon–nitrogen concentrations. Thirty-one species were recorded. Abundance and dry weight biomass at four intensively studied habitats averaged 5000/m2 and 2.1 g/m2, respectively, during 1971. The most exposed habitat yielded twice this standing crop, correlated with intermediate levels of carbon and nitrogen. Over 90% of seasonal numbers and biomass at more exposed habitats were attributable to six species of relatively short-lived amphipods, mostly Haustoriidae. Between-habit at variation in abundance and biomass of amphipods was in general greater than seasonal variation within habitats. Polychaete species increased at sheltered habitats, and bivalve mollusks were restricted to shelter. The typical community of moderately exposed sands south of Penobscot Bay, Maine, is characterized by a recurrent group of nine species (five amphipods). Community stability is assisted by brooding habits of dominant amphipods. Zonation, subtidal connections, seasonal movements, and patterns of amphipod species dominance are discussed. Structural comparisons are made with boreal European and other Atlantic coast intertidal sand communities.

Macroinfauna of northern New England marine sand. I. The biology of Mancocuma stellifera Zimmer, 1943 (Crustacea: Cumacea)

1973 ◽  
Vol 51 (10) ◽  
pp. 1011-1020 ◽  
Author(s):  
W. T. Gnewuch ◽  
R. A. Croker
Keyword(s):  
New England ◽  
New Hampshire ◽  
Life Stage ◽  
Copulatory Behavior ◽  
Seasonal Distribution ◽  
Distribution Data ◽  
Marine Sand ◽  
Two Generations ◽  
Early Fall ◽  
Northern New England

Mancocuma stellifera is found in nearshore subtidal sands from the Gulf of St. Lawrence south to Cape Ann. Massachusetts, with abundance as high as 4000/0.1 m2 in coastal New Hampshire habitats. The species has two generations yearly, with maximum recruitment during June and early fall. Pre-copulatory behavior with opposed orientation of the sexes is unique for the Cumacea. Seasonal distribution data from New Hampshire and Maine to a depth of 7 m below MLW level showed over 90% of the population shallower than the 4-m depth, and abundance maxima at 1–2 m. Manca stages and older juveniles made up most of the population at 5- to 7-m depths during summer months, with manca stages the predominant life stage in night surf plankton tows during peak recruitment. SCUBA and laboratory observations indicated that the species burrows in superficial sand where it is an epistrate and detritus feeder.

Cyprinid distributions in Northeast U.S.A. lakes: evidence of regional-scale minnow biodiversity losses

1997 ◽  
Vol 54 (7) ◽  
pp. 1593-1607 ◽  
Author(s):  
T R Whittier ◽  
D B Halliwell ◽  
S G Paulsen
Keyword(s):  
New York ◽  
Species Richness ◽  
New England ◽  
Fish Assemblages ◽  
Regional Scale ◽  
Median Number ◽  
Southern New England ◽  
Sample Data ◽  
Golden Shiner ◽  
Northern New England

Fish assemblages were sampled in 195 randomly selected lakes in the northeastern United States during the summers of 1991-1994. Most lakes in northern Maine had three to seven minnow species, constituting 40-80% of species in each lake. Lakes in New Jersey, southern New York, and southern New England rarely had minnows, other than golden shiner (Notemigonus crysoleucas). Lakes in the Adirondacks and the remainder of northern New England had intermediate numbers. We examined minnow native ranges and autecology and evaluated species richness related to littoral predators and human disturbance. Sample data suggested alteration in the minnow assemblages over much of the region. The most consistent factor related to minnow species richness was the presence of littoral predators. Median number of minnow species was two in lakes lacking predators and zero in lakes with predators. Non-native predators, especially Micropterus spp., have been introduced throughout the Northeast; 69% of the sampled lakes had non-native predators. In the absence of predators, minnow species declined with increased human activity in the watershed and along lake shorelines. Only in northern Maine did lake minnow assemblages seem relatively intact.

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