Hatch date distributions, local spawning time and incubation temperatures at different spawning sites around Iceland were used to trace the most likely origin of 0-group cod. Length, age and hatch date frequency distributions were obtained from young larvae collected on the main spawning grounds off the south coast in 1995 and from pelagic 0-group cod captured in six nursery regions off the wes...

Post-recruit Illex coindetii and Todaropsis eblanae were collected from the fishery on the Galician shelf between November 1991 and April 1992. Maturity was assessed using a maturity scale. Sex ratios, monthly length frequencies distributions and the relationship between dorsal mantle length (ML) and body weight (BW) of both species were determined. Illex coindetii males were more precocious th...

Understanding mechanisms that support long-term persistence of populations and sustainability of productive fisheries is a priority in fisheries management. Complex spatial structure within populations is increasingly viewed as a result of a plastic behavioral response that can have consequences for the dynamics of a population. We incorporated spatial structure and environmental forcing into a...

Stock-recruitment models have been used for decades in fisheries management as a means of formalizing the expected number of offspring that recruit to a fishery based on the number of parents. In particular, Ricker's stock recruitment model is widely used due to its flexibility and ease with which the parameters can be estimated. After model fitting, the spawning stock size that produces the ma...

In this collaborative research project, we formed a partnership of commercial fisherman and scientists from UNH and NYU to investigate stock definitions for Atlantic cod using DNA markers. Cod in U.S. waters are currently managed as two stocks: 1) a Gulf of Maine stock and 2) a Georges Bank and south stock. This designation is decades old and warrants reevaluation in light of concerns that fish...

That sexually mature fish skip reproduction, especially in response to poor condition, has been documented in many species. We present results from an energy-allocation life history model that shed light on the underlying logic of skipped spawning, based on the Northeast Arctic stock of Atlantic cod (Gadus morhua). The model predicts that skipped spawning is a regular phenomenon, with up to 30%...

Stable carbon isotopes can provide insight into carbon cycling pathways in natural environments. We examined carbon isotope fractionations associated with a hyperthermophilic fermentative bacterium, Thermotoga maritima, and a thermophilic chemolithoautotrophic bacterium Persephonella marina. In T. maritima, phospholipid fatty acids (PLFA) are slightly enriched in 13C relative to biomass (epsilo...

The rate of biomass production is a fundamental property of all organisms in nature, but it is an especially important parameter of microbes in natural aquatic environments. An estimate of microbial production can be used as a general index of microbial activity and specifically to calculate growth rates. Since many processes scale with it, biomass production can be used to obtain a first-order...