Researchers measuring Atlantic striped bass captured during the SEAMAP Cooperative Winter Tagging Cruise. Photo ? ASMFC

Researchers measuring Atlantic striped bass captured during the SEAMAP Cooperative Winter Tagging Cruise. Photo © ASMFC.

Fishery-independent data are collected by scientists conducting long-term resource monitoring projects known as fishery-independent surveys. These surveys are specifically designed to follow consistent methods using the same gear for the duration of the survey in order to develop unbiased and independent indices of abundance. State, federal, and university scientists typically conduct fishery-independent surveys over many years to track long-term abundance trends of fishery resources. These data, when combined with fishery-dependent data from fishermen reports, provide a more accurate picture of stock status. Since the data are not influenced by specific management measures (size and bag limits, season closures, mesh sizes) or socioeconomic factors, they present an unbiased accounting of stock health. These surveys often collect biological data and other information used to describe juvenile and adult abundances, fish habitat characteristics, and environmental factors.  It is this information combined with commercial and recreational harvest data that provides the scientific basis for the Commission’s stock assessments and fisheries management programs.

The Commission’s Fisheries Science Program coordinates two primary Atlantic coast fishery-independent data collection programs – the South Atlantic component of the Southeast Area Monitoring and Assessment Program (SEAMAP) and the Northeast Area Monitoring and Assessment Program (NEAMAP). The Commission also contributes to several other surveys conducted by the states to advance our understanding of key species managed by the Commission.



NEAMAP is a cooperative state/federal program to facilitate the collection, analysis, and dissemination of fishery-independent data in the Northeast area (the Atlantic coastal waters from the Gulf of Maine to Cape Hatteras, NC). Data are collected to support fisheries management, as well as enhance knowledge of marine fish and invertebrate stocks and the ecosystem. Fishery independent data are provided for use by government agencies, recreational and commercial fisheries, researchers, and others. The intent of the Program is to provide coordination among existing fishery-independent surveys in order to optimize activities and maximize the usefulness of data collected by such surveys.

To learn more about NEAMAP, visit


SEAMAP is a cooperative program among state and federal agencies and universities to facilitate the collection, management, and dissemination of fishery-independent data in the Southeastern U.S. and Caribbean. Since 1982, SEAMAP has sponsored long-term standardized surveys that have become the backbone of fisheries and habitat management for its three regions – the South Atlantic, Gulf of Mexico, and Caribbean. SEAMAP-South Atlantic surveys collect data on the abundance and distribution of a variety of important commercial and recreational species (e.g., red drum, Atlantic croaker, Atlantic striped bass) from North Carolina to Florida. The SEAMAP-SA Database is a centralized database that houses SEAMAP-SA affiliated data. Further information about the SEAMAP-SA Database and a link to access data can be found here. Additionally, SEAMAP-South Atlantic continues to support the Southeast Regional Taxonomic Center, maintaining support for the processing and archiving of biological samples collected by SEAMAP surveys.

April 19, 2017 - SEAMAP Releases 5-Year Management Plan


SEAMAP-South Atlantic Longline Surveys

In 2008, the SEAMAP-South Atlantic began supporting bottom longline surveys of the adult red drum population from North Carolina to Florida to develop a better understanding of abundance, distribution, and age composition of the stock and to provide a fishery-independent index of adult red drum abundance. Many red drum encountered in the survey are tagged to provide information on survival rates, migratory behavior, and stock identification. Information is also collected on the presence of hatchery-origin fish in the offshore adult population, as well as sex ratios, maturity, and age structure of the population. All of the information is critical for evaluating the status of the red drum population, especially the adult portion, and developing a successful red drum management program. Information derived from these surveys can also be used for coastal shark assessments in the South Atlantic.

To learn more about SEAMAP, visit


Horseshoe Crab Trawl Survey

The horseshoe crab (Limulus polyphemus) is an ecologically, economically and medically important species occurring on the East Coast of the United States.  Despite supporting a fishery for over 100 years, horseshoe crabs largely were ignored by fisheries managers until increasing commercial landings raised concerns about the sustainability of the resource. The Atlantic States Marine Fisheries Commission (ASMFC) implemented a fishery management plan to regulate the harvest and also noted research needed for providing the requisite data. The horseshoe crab trawl survey, which has been administered by Virginia Tech since 2002, is the only survey designed to sample the horseshoe crab population in coastal waters. Its geographic scope is broad, covering the Atlantic coast from Atlantic City, New Jersey to Wachapreague, Virginia and also the lower Delaware Bay. The survey area is stratified into nearshore and offshore and into trough and non-trough areas and all strata are sampled randomly. Relative abundance of immature and mature males and females are tracked separately. Results show that relative abundance of horseshoe crabs rose following restriction of harvest in 1999 and has fluctuated since 2004. That increases in relative abundance have not continued may be attributed to insufficient time for a species with late age-at-maturity, poor recruitment in recent years, ecological shifts in the near-shore ecosystem, or other factors. 

Relative abundance data from the horseshoe crab trawl survey are a critical component of the Commission’s coastwide horseshoe crab stock assessment and the new Adaptive Resource Management (ARM) framework, both of which were endorsed through an independent peer review in 2009.  The ARM framework includes modeling that links management of horseshoe crab harvest to multispecies objectives, particularly to demographic recovery of imperiled red knots and other shorebirds. The ARM was developed jointly by the Commission, U.S. Fish and Wildlife Service, and U.S. Geological Survey in recognition of the importance of horseshoe crab eggs to migratory shorebirds stopping over in the Delaware Bay Region.

Generally supported by congressionally-directed funds in the past, the horseshoe crab trawl survey could not have been conducted in 2011 and 2012 were it not for funding support contributed by the biomedical and fishing industries, who depend upon a demographically robust population of horseshoe crabs.  Support is being sought to fund the 2013 survey, as well as the long-term continuance of the survey. To learn more about the survey, contact Eric Hallerman at Virginia Tech.


Northern Shrimp Trawl Survey

Northern shrimp awaiting measurement during the Northern Shrimp Trawl Survey. Photo ?Ǭ� ASMFC

Northern shrimp awaiting measurement during the Northern Shrimp Trawl Survey. Photo © ASMFC.

In existence for nearly 30 years, the Gulf of Maine Northern Shrimp Trawl Survey represents one of the longest running cooperative state/federal research surveys alongthe Atlantic coast, and is one of few surveys dedicated to a single species. Established in 1983 and designed to replace the State of Maine Shrimp Survey, which had been conducted since the mid-60s, the survey monitors the relative abundance (number of shrimp), biomass weight of shrimp),  and composition  of the northern shrimp stock throughout the Gulf of Maine. The data give an understanding of year class strength and sex stage and maturity of shrimp in the population. The survey focuses its efforts in offshore waters (in depths greater than 50 fathoms) and is timed to sample both males and females during the summer when they are expected to be offshore. The data it collects forms the basis of the annual northern shrimp assessment, which in turn, is used by fishery managers from Maine, New Hampshire and Massachusetts to set each year’s fishing regulations.

The survey is conducted aboard the R/V Gloria Michelle, a 65-foot, 96 gross ton stern trawler. In addition to the four vessel crew members, the survey is staffed by six scientists for a total crew of ten persons. Scientific staff is provided by the Northeast Fisheries Science Center, the states of Maine, Massachusetts, and New Hampshire, and the Atlantic States Marine Fisheries Commission.

Currently, the survey is carried out about 22 days each summer, divided up into four legs, from the end of July to mid August. The western Gulf of Maine is divided into 10 strata and each stratum is sampled in proportion to its area, except that sampling intensity is doubled in the strata that have had the highest abundances of shrimp historically. Eighty-two sites are sampled, three-quarters of which are randomly selected and the remainder are fixed locations.

To learn more about the survey, please contact Max Appelman, ASMFC Northern Shrimp FMP Coordinator.


Ventless Trap Survey

Researcher measures American lobster captured as part of the Ventless Trap Survey. Photo credit: Trisha Cheney, ME DMR.


Researcher measures American lobster captured as part of the Ventless Trap Survey. Photo credit: Trisha Cheney, ME DMR. 

Although several fishery-independent trawl surveys encounter lobster across their range, trawls are not an ideal gear because they cannot operate on rocky or ledge habitats which lobster often frequent. Also, trawl surveys cannot operate in areas where static gear (e.g., lobster pots and gillnets) is deployed. Therefore, a large portion of the most productive lobster habitat is not accessible to trawl survey gear. In contrast to existing trawl surveys, the Ventless Trap Survey was specifically designed to catch lobster using a more effective gear, the lobster trap.

Commercial lobster traps are required to have an escape vent that allows most sublegal lobster to exit the trap. This escape vent helps reduce the stress and potential mortality associated with being trapped and processed on the boat. The Ventless Trap Survey utilizes multiple sets of 6 traps deployed at the same time in the same location. Three traps are vented and three are ventless. The vented traps are designed to monitor trap catch rates of mostly legal-sized lobster. The ventless traps are designed to collect valuable information about catch rates of sublegal lobster which represent future recruitment to the fishery.

Traps are deployed between June and November in a random stratified fashion such that sets of 6-traps are randomly placed within certain depth categories and geographic areas. Soak time is three nights. All lobster caught in the Ventless Trap Survey are examined and biological information is recorded, including carapace length, sex, egg-bearing status, shell disease condition, and v-notch status.

The Ventless Trap Survey data will be used in the upcoming 2014 American lobster stock assessment to create a new fishery-independent index of abundance. Because carapace length and sex of each lobster caught is recorded, the index can provide the model with vital information about changes in length structure over time for males and females. Also, with the use of ventless traps, data collection will target sublegal lobster, thereby improving our ability to estimate and predict trends in small, sublegal lobster that have not yet recruited to the fishery. States are committed to continuing this important survey given they are successful in securing funding, a definite challenge in today’s fiscal environment.

To learn more about the survey, contact Toni Kerns, ISFMP Director.