A partial glossary of terms used when discussing the Juvenile Striped Bass Survey at the Virginia Institute of Marine Science (VIMS) and other fishery surveys.
The movement of fishes from their primary habitats in marine waters to freshwater rivers and streams to spawn. The striped bass is considered an anadromous species.
A relative measure of the size of a population or sub-unit of the population, such as a year class. It is usually measured as number (or weight) of fish caught per standard unit of fishing effort. In the case of the VIMS Juveile Striped Bass Survey, it is the number of young-of-year striped bass captured per seine haul at selected sampling sites.
Strictly speaking, a juvenile is any fish which is not yet sexually mature. In the context of this type of fish survey, however, it is most often used interchangeably with young-of-year (YOY).
This term has several meanings in fishery science. One definition is the size at which a fish is can be legally caught. Another is the size at which a fish becomes susceptible to a particular fishing gear. In the context of the VIMS Juvenile Striped Bass Survey, it refers to the number of young-of-year striped bass that survive the rigors of their first year to become a part of the overall population.
Need definition here.
A major objective of fisheries scientists is to assess fishery resources by estimating population sizes of fish species and changes within these populations. Many times this involves using a particular kind of fishing gear to measure abundance of species of interest in a given geographic area. The target species determine the type of gear used and consequently the name of the survey. This survey uses a 100 ft. long x 4 ft. deep minnow seine to capture juvenile striped bass and is thus named the VIMS Juvenile Striped Bass Seine Survey.
The act of releasing eggs and sperm into the water. Being an anadromous species, striped bass leave the ocean and move into freshwater reaches of Chesapeake Bay to spawn. The juvenile fish remain in the fresh and brackish (and sometimes salty) areas of the Bay for 1 to 3 years to age and mature.
Most fish species in temperate waters (like those found in Chesapeake Bay and off the coast of Virginia) reproduce during a relatively short (one or two month) period each year. That period may be different for each species. Fisheries scientists refer to all of the fish of any species hatched during one annual spawning period as a year class. For mathematical purposes, fishery analysts often treat members of the year class as if all fish were hatched on one day. In lower Chesapeake Bay, striped bass spawn from late March through May of each year. In the case of the VIMS Juvenile Striped Bass Survey, all fish hatched during this period are recognized as a year class.
All of the fish of a species younger than one year of age. Usually scientists assign an arbitrary "birth date" to all fish of a species hatched over a two or three month period in a given year. The fish are then assigned Age 1 status on that birth date; this is usually January 1.