Shore-based angler proudly displaying a spot he caught. Photo credit: Virginia Marine Resources Commission
Spot (Leiostomus xanthurus) occur along the U.S. Atlantic coast in estuarine and coastal waters from the Gulf of Maine to Florida, although they are most abundant from Chesapeake Bay to South Carolina. Spot migrate seasonally, entering bays and estuaries in the spring where they remain until late summer or fall when they move offshore to spawn. Spot mature between the ages of two and three, at lengths of seven to eight inches. Their maximum life span is about six years, although fish older than four years are uncommon.
Spawning takes place in the ocean from fall to early spring and the post-larvae move into estuaries, utilizing low salinity tidal creeks where they develop into juveniles. As spot grow, they move toward higher salinity areas during the summer and early fall and offshore in the fall as water temperatures decrease. Those that summered in the northern portion of their range also move south in the autumn. Spot are opportunistic bottom feeders, eating mainly worms, small crustaceans and mollusks, and organic material. The post-larvae prey on plankton but become bottom feeders as juveniles or adults. Predators such as striped bass, weakfish, summer flounder, bluefish, and sharks eat them in turn.
Spot provide important recreational and commercial fisheries in the South Atlantic, although year-to-year fluctuations in landings are common. This is because spot are short-lived and the catch in most years consists of a single year-class, the strength of which is variable (partly due to environmental conditions prevalent in the spawning and nursery areas).
Spot are caught commercially along the Atlantic coast, particularly from Chesapeake Bay southward. They are harvested by a variety of commercial gears including haul seines, pound nets, gillnets, and trawls. Commercial catches fluctuated widely between 1950 and the early 1980s, ranging from 3.9 to 14.5 million pounds. Such variability is expected because spot are a short-lived species and catch in most years consists of a single year class, the strength of which appears to be determined by environmental conditions that prevail on the spawning and nursery grounds in any particular year. Landings show less year-to-year variability from 1984 to 2011, ranging from 2.1 to 8.8 million pounds. Commercial harvest in 2015 was estimated at 2.16 million pounds, a three million pound decrease from 2014 and a one million pound decrease from 2013. This catch is largely landed by gillnets. Small spot are also a major bycatch of the haul seine and pound net fisheries in Chesapeake Bay and North Carolina, as well as a significant part of the bycatch of the South Atlantic shrimp trawl fishery. However, substantial reductions in the magnitude of bycatch have occurred in the latter fishery in recent years.
For the past three decades, recreational harvest along the Atlantic coast has varied between 1.7 and 6.9 million pounds. Recreational harvest showed an increasing trend from the low of 3.6 million pounds in 1999 to a high of 5.5 million pounds in 2007. In 2015, recreational harvest was 2.27 million pounds.
Throughout 2016, work continued on the first coastwide benchmark stock assessment for spot. The assessment seeks to estimate population parameters (e.g., stock status, natural mortality, discard rates and mortality) and biological reference points, and is scheduled to undergo review in early 2017.
In between stock assessments, a TLA is used to evaluate stock status. Established under Addendum I, the TLA is a precautionary management framework which evaluates fishery trends and develops management actions. The name comes from assigning a color (red, yellow, or green) to categorize relative levels of population indicators which reflect the condition of the fish population (abundance metric) or fishery (harvest metric). For example, as harvest or abundance increases relative to its long-term mean, the proportion of green in a given year increases and as harvest or abundance decreases, the amount of red in that year becomes more predominant. Harvest and abundance thresholds of 30% and 60% were established in Addendum I, representing moderate and significant concern for the fishery. The TLA illustrates long-term trends in the stock and includes specific management recommendations in response to declines in the stock or fishery.
Due to the ongoing assessment, a TLA was not conducted for spot in 2016. The 2015 TLA showed a significant decrease in spot harvest in both the commercial and recreational sectors. Data from fishery independent surveys also showed a decrease in the abundance of spot coastwide. Management measures were not tripped in 2014 since the abundance index was just below the management threshold; however, the TLA does show a declining trend in the fishery which warrants close monitoring in the future.
Spot is one of the 275 sciaenid species worldwide. The Commission manages six sciaenid species, which are commonly called drums, croakers, or hardheads for the repetitive throbbing or drumming sounds they produce. Spot is managed under the Omnibus Amendment for Spot, Spotted Seatrout, and Spanish Mackerel (2011) and Addendum I (2014). The Omnibus Amendment updates all three species plans with requirements of the Commission's ISFMP Charter. As discussed above Addendum I establishes use of a Traffic Light Analysis to evaluate the status of the fisheries and potential coastwide or state-specified management actions (e.g. bag limits, size restrictions, time & area closures, and gear restrictions) based on the annual fisheries evaluation. The TLA has been used as a precautionary framework for fisheries with limited data to allow for a reasonable level of resource management.