Judith S. Weis



Most of our research focuses on the effects of stressors like environmental contaminants, invasive species, and parasites on the behavior and ecology of estuarine organisms. We are interested in responses at the organismal level, such as changes in development, growth, or behavior; responses at the population and community level, such as the development of tolerance on the part of populations that are chronically exposed to certain pollutants, altered life histories, alterations in predator/prey interactions and trophic transfer of contaminants.

We are interested in the role of salt marsh plants in providing nutrition and transferring toxicants to animals. We are comparing the native marsh plant, Spartina alterniflora with the invasive reed, Phragmites australis in terms of their use as habitat by fiddler crabs, grass shrimp and larval mummichogs, and their nutritional value to the marsh invertebrates. We are also comparing metal uptake, storage and release by these two plants in the Hackensack Meadowlands. Data gathered thus far indicate that Spartina accumulates and releases greater amounts of metals than Phragmites, and that the two plants seem to be equivalent as food, once they have been converted to detritus, and to serve the same habitat function for some but not all of the animals. Epifauna that live on stems seem to prefer Spartina, as do mummichogs that utilize the marsh surface at high tide. Some of this work is being done in conjunction with the Meadowlands Environmental Research Institute, MERI, which supports joint research projects of several faculty members and is sponsored by the New Jersey Meadowlands Commission (NJMC).

The proximity to the Hackensack Meadowlands and Newark Bay, which is a severely stressed estuary, gives us a convenient "outdoor laboratory." We have found such tolerance to methylmercury in populations of mummichogs (Fundulus heteroclitus), grass shrimp (Palaemonetes pugio) and fiddler crabs (Uca pugnax) from the northern NJ estuaries, but have also found that enhanced tolerance comes at a price. We are currently looking at impaired feeding behavior in these fish. They are less capable of capturing live prey, and consequently eat higher proportions of sediment and detritus, which are not nutritious. The reduced prey capture is associated with lower general activity level and reduced levels of serotonin in their brains. We are also looking into the possible involvement of the thyroid gland in their low activity level. This may be a case of endocrine disruption caused by environmental contaminants. Their poor diet may be partly responsible for their decreased growth and life span. However, their prey organisms, grass shrimp (Palaemonetes pugio), whose predator-avoidance does not seem to be impacted by the contaminants in the polluted environment, may be benefiting from being preyed upon less. They are larger in size as well as more numerous at the contaminated site.

Faculty Related Websites

Lab website


B.A., Cornell University.
M.S., Ph.D., New York University.


Weis, J.S.  2012.  Walking Sideways  The Remarkable World of Crabs.  Cornell University Press.

Weis, J.S., and A. Candelmo.  2012.  Pollutants and fish predator/prey behavior:  A review of laboratory field approaches.  Current Zoology 58: 9-20.

Weis, J.S., Bergey, L., Reichmuth, J., and A. Candelmo.  2011.  Living in a Contaminated Estaury:  Behavioral Changes and Ecological Consequences for Five Species.  Bioscience 61: 375-385.

Weis, J.S.  2011.  Invasion and predation in aquatic ecosystems.  Current Zoology 57: 613-624.

Reichmuth, J.M., MacDonald, J., Ramirez, J., and J.S. Weis.  2011.  Fight or flight:  an investigation of aggressive behavior and predator avoidance in two populations of blue crabs (Callinectes sapidus Rathbun) in New Jersey.  Hydrologia 658:  173-182. 

Burridge, L., J.S. Weis, F. Cabello, J. Pizarro and K. Bostick.  2010. Chemical use in salmon aquaculture: A review of current practices and possible environmental effects.  Aquaculture  306: 7-23.

Candelmo, A., A. Deshpande, B. Dockum, P. Weis and J. S. Weis.  2010. The effect of contaminated prey on feeding, activity, and growth of young-of-the-year bluefish, Pomatomus saltatrix, in the laboratory. Estuaries and Coasts 33: 1025-1038.

Weis, J.S. 2010. The role of behavior in the success of invasive crustaceans. Mar. Freshwat. Behav. Physiol. 43: 83-98.

Reichmuth, J.M., P. Weis and J.S. Weis. 2010. Bioaccumulation and depuration of metals in blue crabs (Callinectes sapidus Rathbun) from a contaminated and clean estuary. Environ. Pollut. 158: 361-368.

Weis, J.S. and C.A. Butler. 2009. Salt Marshes: A Natural and Unnatural History. Rutgers University Press.

Weis, J.S. 2009. Reproductive, Developmental, and Neurobehavioral Effects of Methylmercury in Fishes. Journal of Environmental Science and Health, Part C 27: 212-225.

MacDonald, J., S. Shahrestani and J.S. Weis. 2009. Behavior and space utilization of two common fishes within Caribbean mangroves: implications for the protective function of mangrove habitats. Estuarine, Coastal and Shelf Science, 84: 195-201.

Weis, J.S., P. Weis, L. Pearson, J. MacDonald. 2009 Rapid changes in fish utilization of mangrove habitat in Western Madagascar.  Wetland Ecol. Management  17: 345-354.

Bass, C.S. and J.S. Weis. 2009. Conspicuous behavior of Fundulus heteroclitus associated with high digenean metacercariae gill abundances. J. Fish Biol. 74: 763-772.

Reichmuth, J.M., R. Roudez, T. Glover and J.S. Weis. 2009. Differences in prey capture behavior in populations of blue crab (Callinectes sapidus Rathbun) from contaminated and clean estuaries in New Jersey. Estuaries and Coasts 32: 298-308.

MacDonald, J., T. Glover, and J.S. Weis. 2008 The impact of mangrove prop-root epibionts on juvenile reef fishes: a field  experiment using artificial roots and epifauna. Estuaries and Coasts 31:981-993.

Roudez, R.J., T. Glover and J.S. Weis. 2008. Learning in an invasive and a native predatory crab. Biol. Invasions 10: 1191-1196.

Bass, C.S. and J.S. Weis 2008. Increased abundance of snails and trematode parasites of Fundulus heteroclitus (L.) in restored New Jersey wetlands. Wetland Ecol. Mgmt. 16:173-182.

Bergey, L. and J.S Weis. 2008. Aspects of population ecology in two populations of fiddler crabs, Uca  pugnax. Marine Biology 154: 435-442.

Samson, J.C., S. Shumway and J.S. Weis. 2008. Effects of the toxic dinoflagellate Alexandrium fundyense on three species of larval fish: a food web approach. J. Fish Biol. 72: 168-188.

Bergey, L. and J.S. Weis. 2007. Molting as a mechanism of depuration of metals in the fiddler crab, Uca pugnax. Marine Environmental Research 64: 556-562.

Bass, C.S. , S. Khan and J.S. Weis. Associations of gill branching with gill parasite infections in Fundulus heteroclitus. J. Fish Biol. 71: 920–925.

Mac Donald, J., R. Roudez, T. Glover and J.S. Weis. 2007. Interactions between native blue crabs and invasive green crabs and Japanese shore crabs. Biol Invasions 9: 837–848.

Robertson, T.A. and J.S. Weis. 2007. Interactions between the grass shrimp, Palaemonetes pugio and the salt marsh grasses Phragmites australis and Spartina alterniflora. Biol Invasions 9: 25–30.

Wirgin, I., J.S. Weis, and A. McElroy. 2006. Physiological and Genetic Aspects of Toxicity in Hudson River species. Pages 441–464 in: J. Levinton and J. Waldman, eds. The Hudson River Estuary. Cambridge University Press.

Weis, J.S. and P. Weis. 2006. Effects of  wood treated with chromated copper arsenic on aquatic biota. Pages 173–190iIn: Environmental Impacts of Treated Wood, ed. T. Townsend & H. Solo-Gabriele. CRC Press.

Yuhas, C., J.M. Hartman and J.S. Weis. 2005. Benthic communities associated with Spartina alterniflora and Phragmites australis in the Hackensack Meadowlands of NJ. Urban Habitats 3(1): 158–191.

Weis, J.S. 2005. Diet and food web support of the white perch, Morone americana in the Hackensack Meadowlands. Environ. Biol. of Fishes 74: 109–113.