Northern shrimp from offshore waters in the Gulf of Maine were studied to determine their occurrence and to learn some major features of their life history. The area sampled extends from Nova Scotia, Canada, to Long Island, New York. Northern shrimp were found only in the western portion of the Gulf of Maine, where they were present throughout the year, and at two isolated localities southeast of Nova Scotia. Abundance was highest in moderate depths in the vicinity of Jeffrys and Cashes Ledges and southeast of Mount Desert Island, Maine, and lowest in the deeper, offshore areas in the west-central part of the Gulf. High water temperatures appear to limit the southward extension of this species off New England. Within the Gulf of Maine this shrimp occurs on fine-grained bottom sediments, such as clay, silty sand, and glacial till, which contain relatively large amounts of organic matter. Average life span is about 3« years and may extend to 4« years for a small portion of the population. Northern shrimp are protandric hermaphrodites, functioning first as males. Spawning is in August and September. Most of the shrimp spawn only once as females-about 20% at 2% years of age, 70% at 3% years, and 10% at 4% years. The eggs remain attached to the pleopods for about 6 months and hatch in the spring (March and April). Egg-bearing females migrate from the deeper (offshore) waters to shallow (inshore) areas during the maturation period. It is the egg-bearing females, which are concentrated near the mouths of estuaries and other nearshore areas, that make up the bulk of the commercial catch. The number of eggs per clutch increases with shrimp size and averages 2,400 (range, 800 to 3,400). Length-weight relations are similar for males and nonovigerous females; ovigerous females are about 1.4 g heavier for any given length than the nonovigerous ones. Growth rate of the Gulf of Maine population is faster at ages of 2 years and older than that of any other population of this species reported to date. E. B. HAYNES AND R. L. WIGLEY NEW O• 120 JERSEY iYORK • ' ' ',' -, NEW CONCTICUT "X '• ' ß ß ß ß ß ß ß ß ß ß ß ß ß ß ß ß ß • • ß ß ß • •e e•e e ß e• e e ß • • ß NOVA 72' SCOTIA ß ß ß ß •.•, ß ß ß ß ß ß ß ß ß ß ß ß ß I TO 5 STATIONS ß q,.

From the mid-1950s to the mid-1 960's a series of quantitative surveys of the macrobenthic invertebrate fauna were conducted in the offshore New England region (Maine to Long Island, NewYork). The surveys were designed to 1) obtain measures of macrobenthic standing crop expressed in terms of density and biomass; 2) determine the taxonomic composition of the fauna (ca. 567 species): 3) map the general features of macrobenthic distribution; and 4) evaluate the fauna's relationships to water depth, bottom tvpe, temperature range, and sediment organic carbon content. A total of 1,076 samples, ranging from 3 to 3,974 m in depth, were obtained and analyzed. The aggregate macrobenthic fauna consists of 44 major taxonomic groups (phyla, classes, orders). A striking fact is that only five of those groups (belonging to four phyla) account for over 80% of both total biomass and number of individuals of the macrobenthos. The five dominant groups are Bivalvia, Annelida, Amphipoda, Echninoidea, and Holothuroidea. Other salient features pertaining to the macrobenthos of the region are the following: substantial differences in quantity exist among different geographic subareas within the region, but with a general trend that both densitv and biomass increase from northeast to southwest; both densitv and biomass decrease with increasing depth; the composition of the bottom sediments significantlv influences both the kind and quantity of macrobenthic invertebrates, the largest quantities of both measures of abundance occurring in the coarser grained sediments and diminishing with decreasing particle size; areas with marked seasonal changes in water temperature support an abundant and diverse fauna, whereas a uniform temperature regime is associated with a sparse, less diverse fauna; and no detectable trends are evident in the quantitative composition of the macrobenthos in relation to sediment organic carbon content.

Areas of several bathymetric zones within each subarea and total area of Middle Atlantic Bight region __ 5 Quantitative taxonomic composition of the macrobenthic invertebrate fauna, in both number of individuals and biomass, representing the entire Middle Atlantic Bight region

Two commonly used benthos samplers, van Veen and Smith—McIntyre, were tested to detect possible adverse characteristics for sampling epibenthic animals. A strong hydraulic disturbance (shock wave) was formed below the van Veen sampler as it descended through the water toward bottom. In this sampler the shock wave was sufficiently strong to force aside unattached benthic animals as long as 8 cm. The Smith—McIntypre sampler created only a weak, oscillatory shock wave. Available information indicates that, under standard operating procedures, the smaller the screened opening in the top of the sampler's jaws the stronger the shock wave.

Quantitative samples were taken from the offshore arca south of Martha's Vineyard,