What is ChesMMAP?

  • R/V Virginia from the air
    R/V Virginia from the air    
  • ChesMMAP 200 x 12 cm net in the water
    ChesMMAP 200 x 12 cm net in the water    
  • Haulback! Time to empty the net and sort the catch.
    Haulback! Time to empty the net and sort the catch.    
  • ChesMMAP Sorting Table
    ChesMMAP Sorting Table    
  • Back deck of the R/V Virginia outfitted with ChesMMAP Gear
    Back deck of the R/V Virginia outfitted with ChesMMAP Gear    
  • R/V Virginia
    R/V Virginia     Jim Goins
  • Emptying the catch from the net
    Emptying the catch from the net    
Photo - of -

The Chesapeake Bay Multispecies Monitoring and Assessment Program, ChesMMAP, began in 2002 and was developed to assist in filling data gaps, and ultimately to support Bay-specific, stock-assessment modeling activities at both single and multispecies scales. ChesMMAP was designed to maximize the biological and ecological information collected for several recreationally, commercially, and ecologically important species in Chesapeake Bay. The survey uses a large-mesh bottom trawl to sample juvenile-to-adult fishes from the head of Chesapeake bay at Poole's Island, MD to the mouth of the Bay just outside the Chesapeake Bay Bridge Tunnel.

Survey Goals
  • To estimate population sizes for priority species
  • To quantify geographic and seasonal distribution of these species
  • To quantify major links in the Bay's food web by conducting stomach content analysis for all species sampled
  • To define the seasonal length and age structure of the fish and elasmobranch populations by taking otolith (ear bone)  or vertebrae samples from the individuals collected.
Field Methods
ChesMMAP Stations Bay Eagle
GIS Maps

Catch Maps

These interactive maps provide a dropdown menu to select a species to view catch numbers and biomass integrated with a quantitative chart summary and water quality overlays.

Archived Catch Maps

Archived Water Quality

Largest Fishes Map Tour

Abundance Indices
 Atlantic croaker  black seabass
 blue crab - adult female  blue crab - male
 bluefish  butterfish
 clearnose skate  kingfish spp.
 northern puffer  scup
 spot  striped bass - March
 striped bass - November  summer flounder
 weakfish  white perch - March
 white perch - November         
Data Uses

Fishery-independent data resulting from the ChesMMAP Trawl Survey have been requested by stock assessment scientists for a variety of species.  Again, because of the relatively short time series currently available for this survey, the incorporation of abundance indices generated by the ChesMMAP Survey has only been possible for two species: scup and weakfish.  Similar to the situation with NEAMAP, the biological data produced by this survey have been included in the assessments for alewife, blueback herring, bluefish, butterfish, summer flounder, scup, spot, and weakfish.  The assessment scientists expressed their desire to include these data in future assessments as well, again indicating that time series length, and not data quality, is the issue at hand.  Currently, ChesMMAP survey data are being used to guide the assessments for Atlantic croaker and black drum.  An informal assessment of sheepshead data collected by ChesMMAP has been supplied to the Virginia Marine Resources Commission to support review of current management regulations for this species in the Commonwealth, and summer flounder catch and length-frequency data have been used to support the liberalization of recreational harvest regulations for 2011.

From the perspective of ecosystem-based multispecies modeling and management, ChesMMAP diet data have been used to support the development of a fisheries ecosystem model of Chesapeake Bay and a multispecies virtual population analysis of Atlantic menhaden along the U.S. east coast.  These data have also been used to both formally and informally quantify the predatory impact of fishes on their prey (e.g., striped bass, weakfish, and bluefish consumption of menhaden; striped bass impact on blue crabs).  It is expected that the inclusion of ChesMMAP diet data into multispecies efforts will increase as these relatively new assessment approaches continue to develop.  Finally, ChesMMAP abundance and biological data for summer flounder were used to explore yield-per-recruit and egg-per-recruit analyses for this species under a variety of regulatory scenarios for the recreational fishery.  The results of this study were requested and reviewed by the ASMFC in their discussions of a possible slot limit management regime for this species.

Uses of Data Generated by the Chesapeake Bay Multispecies Monitoring and Assessment Program (ChesMMAP) Trawl Survey, 2007-2017

Assessment Related (NMFS & ASMFC)

            Data requested for and incorporated into past assessments

  • Atlantic Menhaden – Predator diet data for inclusion in Multispecies VPA
  • Atlantic Sturgeon – Abundance data for ESA listing and subsequent re-evaluation
  • Black Sea Bass – Abundance, distribution, & age
  • Bluefish – Age
  • Scup – Abundance, distribution, & age
  • Striped Bass – Abundance, distribution, length, & age
  • Summer Flounder – Abundance, distribution, & age
  • Weakfish – Abundance, distribution, & age

Data requested and evaluated for but not incorporated* into an assessment

            *Due to short time series of data & relatively low catches available, NOT because of data quality.

  • Black Drum – Abundance, distribution, length, sex, maturity, & age
  • Bluefish – Abundance, distribution, length, sex, maturity, & age
  • Butterfish – Abundance, distribution, length, sex, maturity, & age
  • River Herring (Alewife & Blueback) – Abundance, distribution, length, sex, & maturity

Data requested for an assessment & results currently pending

  • Atlantic Croaker – Abundance, distribution, length, sex, maturity, & age
  • Spot – Abundance, distribution, length, sex, maturity, & age
  • Tautog – Abundance, distribution, length, sex, & maturity


  • Sheepshead – Data provided to Marine Resources Commission for review of harvest regulations
  • Summer Flounder – Setting of conservation equivalency measures

 Additional Research Efforts

  • Atlantic croaker, black drum, kingfish, & spot - population genetics with South Carolina DNR
  • Atlantic croaker & spot - ageing exchange with ASMFC partners
  • Atlantic croaker, striped bass, & weakfish - collaboration with the VIMS Juvenile Fish and Blue Crab Trawl Survey to explore the relationships between recruitment indices and adult abundance
  • Atlantic croaker & white perch - quantified capture efficiency of the survey trawl for these two species, which both established necessary protocols for such work and facilitates the estimation of absolute abundance for these species
  • Black sea bass - hard part (scale/otolith) comparison for ageing
  • Blue crab collaboration with Conservation Biology division at VIMS to conduct a bay-wide tagging program meant to evaluate the effectiveness of the Chesapeake Bay blue crab spawning stock sanctuary
  • Bluefish, striped bass, summer flounder, & weakfish – development of consumption estimates for these top piscivores in Chesapeake Bay
  • Coastal sharks & Atlantic sturgeon - tagging studies in collaboration with NMFS.
  • Multispecies – supported investigation of community-level responses of fish condition to environmental covariates in Chesapeake Bay
  • Scup - hard part (scale/otolith) comparison for ageing
  • Summer flounder 
    • supported sampling to quantify first year growth and habitat preferences
    • hard part (scale/otolith) comparison for ageing (ongoing)
    • provided biological data to support yield-per-recruit/egg-per-recruit analyses to examine various regulatory scenarios for the recreational fishery (with ASMFC)
    • investigation of trophic dynamics which resulted in this species being classified as one of the top piscivores in the Chesapeake ecosystem
  • Tautog - population genetics with Virginia Marine Resources Commission (ongoing)
  • Striped bass - sampling to identify prevalence and severity of Mycobacterium infection in the coastal migratory population; showed infection contributed both to reductions in growth rates and to increases in natural mortality rates
  • Sampled livers of multiple species for contaminant analysis in collaboration with Clemson University
  • Expanded sampling into tributaries of Chesapeake Bay to sample fishes for contaminant analysis as part of the National Coastal Assessment effort (collaboration with the EPA)
  • Collected voucher specimens of multiple species in collaboration with Smithsonian to establish a genetic library of fishes in the Chesapeake Bay
  • Provided data on multiple species to support the development of an ecosystem model for the Chesapeake Bay
  • Completed an analysis of 10 years of ChesMMAP data to identify patterns and drivers of the demersal fish community in Chesapeake Bay
  • Began testing of a 200 x 12 cm, three-bridle, four-seam survey trawl for use by ChesMMAP. This net is more efficient than the current gear and is more comparable to the trawls used by NEAMAP along the coast and the Northeast Fisheries Science Center offshore.  Specifically, this “200 x 12 cm” net is identical in design, but half of the size of, the nets used by those ocean surveys.
  • Supported research conducted by 4 Master’s and 3 PhD students to date
  • Resulted in development of a manuscript focused on quantifying the patterns and drivers of condition across a range of species inhabiting Chesapeake Bay
  • Received over 200 visits to our online catch and diet databases since initialized in early 2012



ChesMMAP is currently funded by Wallop-Breaux funds from the Virginia Marine Resources Commission and the Commonwealth of Virginia.

VMRC Logo Virginia State Seal