Fisheries Inventory
Our Projects
project lead
Drew McQuade
inventory
The New Jersey Meadowlands is a roughly 30 square mile mosaic of wetlands and uplands located within the highly urbanized New York-New Jersey Harbor Estuary. The main drainage of the Meadowlands, the Hackensack River, flows for about 45 miles from its headwaters in Rockland County, New York to the mouth of Newark Bay. The Oradell Dam separates the river into a freshwater upper section and a tidally influenced lower section. The salinities in the approximately 12.5 river-miles of the lower Hackensack that flow through the Meadowlands range from 2-3ppt in the more northern upriver areas to nearly 20ppt in the southern reaches closer to Newark Bay.
MRRI has been conducting fisheries inventories in the New Jersey Meadowlands for nearly 40 years. Collections for the inaugural Meadowlands Fisheries Inventory occurred in 1987-88, and were followed by a second inventory in 2001-03, a third inventory in 2013-15. The most recent inventory, which began collections in 2023, is set to conclude in the spring of 2025. These inventories consist of two years of seasonal collections at standardized locations throughout the Hackensack River and its tributaries. They use different net types to sample the fisheries community to track changes in the population over time. At its inception in 1987-88, the inventory data indicated that the river was largely dominated by the highly pollution and disturbance tolerant mummichog (Fundulus heteroclitus), with limited higher trophic level fish, indicating that the Meadowlands was not supporting a robust and healthy aquatic community. The second and third inventories showed an improvement in the diversity and trophic function of the fish community, with decreasing dominance of mummichug, and an increasing diversity and prevalence of higher trophic level fish such as striped bass (Morone saxitilis) and white perch (Morone americana). This improvement was attributed to great increases in water quality and abundance of habitat compared to that of the first inventory. The increase in water quality was likely due to the cessation of much of the heated discharge from three different generating stations and the installation of leachate control systems on the district’s landfills. This allowed for the collection and treatment of millions of gallons of toxic leachate which would have otherwise discharged into the river. The increase in habitat quality was due to over 1000 acres of wetland restoration that occurred in the district over that time period. While not yet completed, the data from the current inventory suggests that species more commonly associated with coastal estuaries are increasing in distribution and abundance. This presents a unique situation, as the Meadowlands is becoming increasingly more like a coastal estuary despite being located in the Piedmont Physiogeographic Region.
edna
Environmental DNA (eDNA) is DNA left behind as a species moves through its habitat. This DNA can be sampled for and compared against known genetic markers to identify occurrences and possibly abundance of individual species. Compared to more traditional methods of sampling fish, eDNA is completely non-invasive to the fish, making it a great method for sampling for vulnerable, cryptic, and/or ecologically important species. While this technology is relatively new, it has shown to be a useful technique in a variety of terrestrial and aquatic habitats, sampling for everything from marine mammals to tiny insects. However, the effectiveness of eDNA in urbanized areas is relatively understudied. This study aims to assess the effectiveness of eDNA sampling in the Hackensack Meadowlands by taking eDNA samples paired with traditional fish sampling methods to see how comparable the data between the two techniques is. This study will also evaluate the practicability of implementing more eDNA sampling into future fisheries work, as well as the possibility of using eDNA to sample for other rare and/or cryptic species in the Meadowlands.
icthyoplankton
Icthyoplankton refers to larval stage fish and eggs swimming or floating in the water column, and can be sampled as a metric of spawning success. While the return of higher trophic level fish has been well documented in the Hackensack River, it is unknown if fish are successfully using the river and its tributaries to spawn. Wetlands, including brackish water marshes, are known spawning grounds for fish, and evidence of spawning is generally used as an indicator of marsh health. The upper levels of the water column are sampled with specially designed fine-mesh nets to capture eggs, larval fish, other zooplankton, and microplastics.
Icthyoplankton will be sorted and identified by MRRI scientists, and any zooplankton and plastics will be given to the Fitzgerald Lab at New Jersey City University (NJCU) for identification and quantification. The fish samples will be identified to the lowest possible taxonomic unit and will be quantified for basic abundance, and an estimate of density using a flow meter attached to the mouth of the nets. Data collected from this sampling will be included in the fourth iteration of the Meadowlands Fisheries Inventory.
