35 resultados para Labor--New England


Relevância:

80.00% 80.00%

Publicador:

Resumo:

The year 1985 was one of celebration for the Woods Hole Laboratory of the National Marine Fisheries Service's Northeast Fisheries Center. The reason was the one hundredth anniversary of the completion and occupation of the first facility in the world dedicated to marine fisheries research. Spencer Fullerton Baird, Assistant Secretary of the Smithsonian Institution, and newly appointed first Commissioner of the nascent U.S. Commission of Fish and Fisheries visited Woods Hole in the summer of 1871 to establish a base from which to begin the investigations mandated by Congress when they established the "Fish Commission." During the following three summers (1872-74), operations were conducted from several other localities along the New England coast. During the course of those four years Baird determined that Woods Hole offered the most suitable natural and physical amenities for the investigations being conducted by the Fish Commission at that time, and for those envisioned for the future. The base for Commission operations was returned to Woods Hole in the summer of 1875 and has remained there ever since, through times fair and foul and several agency changes.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

The modern fishery for Tilefish (Lopholatilus chamaeleonticeps) developed during the 1970s, offshore of southern New England, in the western North Atlantic Ocean. The population quickly became over exploited, with documented declines in catch rates and changes in demographic traits. In an earlier study, median size at maturity (L50) of males declined from 62.6 to 38.6 cm fork length (FL) and median age at maturity (A50) of males declined from 7.1 to 4.6 years between 1978 and 1982. As part of a cooperative research effort to improve the data-limited Tilefish assessment, we updated maturity parameter estimates through the use of an otolith aging method and macroscopic and microscopic evaluations of gonads. The vital rates for this species have continued to change, particularly for males. By 2008, male L50 and A50 had largely rebounded, to 54.1 cm FL and 5.9 years. Changes in female reproductive schedules were less variable among years, but the smallest L50 and youngest A50 were recorded in 2008. Tilefish are dimorphic, where the largest fish are male, and male spawning success is postulated to be socially mediated. These traits may explain the initial rapid decline and the subsequent rebound in male L50 and A50 and less dramatic effects on females. Other factors that likely contribute to the dynamics of maturity parameter estimates are the relatively short period of overfishing and the amount of time since efforts to rebuild this fishery began, as measured in numbers of generations. This study also confirms the gonochoristic sexual pattern of the northern stock, and it reveals evidence of age truncation and relatively high proportions of immature Tilefish in the recent catch.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

With the southern New England lobster fishery in distress, lobster fishermen have focused more effort toward harvesting channeled whelk (Busycotypus canaliculatus). However, minimal research has been conducted on the life history and growth rates of channeled whelk. Melongenid whelks generally grow slowly and mature late in life, a characteristic that can make them vulnerable to overfishing as fishing pressure increases. We sampled channeled whelk from Buzzards Bay, Massachusetts, in August 2010 and in July 2011, studied their gonad development by histology, and aged them by examining opercula. Males had a slower growth rate and a lower maximum size than females. Male whelk reached 50% maturity (SM50) at 115.5 mm shell length (SL) and at the age of 6.9 years. Female whelk reached SM50 at 155.3 mm SL and at the age of 8.6 years. With a minimum size limit of 69.9 mm (2.75 in) in shell width, males entered the fishery at 7.5 years, a few months after SM50, but females entered the fishery at 6.3 years, approximately 2 years before SM50. Increased fishing pressure combined with slow growth rates and the inability to reproduce before being harvested can easily constrain the long-term viability of the channeled whelk fishery in Massachusetts.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

The invasive colonial tunicate Didemnum vexillum has become widespread in New England waters, colonizing large areas of shell-gravel bottom on Georges Bank including commercial sea scallop (Placopecten magellanicus) grounds. Didemnum vexillum colonies are also fouling coastal shellfish aquaculture gear which increases maintenance costs and may affect shellfish growth rates. We hypothesized that D. vexillum will continue to spread and may affect shellfish larval settlement and survival. We conducted a laboratory experiment to assess interactions between larval bay scallops (Argopectin irradians irradians) and D. vexillum. We found that larval bay scallops avoid settling on D. vexillum colonies, possibly deterred by the low pH of the tunicate’s surface tissue. The results of this study suggest that widespread colonization of substrata by D. vexillum could affect scallop recruitment by reducing the area of quality habitats available for settlement. We propose that the bay scallop can serve as a surrogate for the sea scallop in estimating the negative impact D. vexillum could have on the recruitment of sea scallops on Georges Bank.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Analysis of 32 years of standardized survey catches (1967–98) indicated differential distribution patterns for the longfin inshore squid (Loligo pealeii) over the northwest Atlantic U.S. continental shelf, by geographic region, depth, season, and time of day. Catches were greatest in the Mid-Atlantic Bight, where there were significantly greater catches in deep water during winter and spring, and in shallow water during autumn. Body size generally increased with depth in all seasons. Large catches of juveniles in shallow waters off southern New England during autumn resulted from inshore spawning observed during late spring and summer; large proportions of juveniles in the Mid-Atlantic Bight during spring suggest that substantial winter spawning also occurs. Few mature squid were caught in survey samples in any season; the majority of these mature squid were captured south of Cape Hatteras during spring. Spawning occurs inshore from late spring to summer and the data suggest that winter spawning occurs primarily south of Cape Hatteras.