Age and Growth
Atlantic croaker (Micropogonias undulatus) Otolith are one of the most abundant inshore demersal fishes along the southeastern coast of the United States. This species has been reported to live over 15 years old.
Atlantic croaker (Micropogonias undulatus) This sectioned croaker otolith is 6 years old. The oldest Atlantic croaker aged by our surveys: ChesMMAP Survey 18 years old, NEAMAP Survey 12 years old
Black drum (Pogonias cromis) Otolith are a long-lived fish and are the largest member of the family Sciaenidae on the Atlantic coast.
Black drum (Pogonias cromis) This sectioned black drum otolith is 41 years old. The oldest black drum aged by ChesMMAP was 54 years old.
Black seabass (Centropristis striata) Otolith are protogynous hermaphrodites that is, initially they are females, but larger fish reverse sex to become males. Black seabass are reported to live as long as 20 years, however, individuals longer than 15 inches, the size of an approximately 8 year old fish, are uncommon. (Source: Fishes of the Chesapeake Bay)
Bluefish (Pomatomus saltatrix) Otolith are a migratory pelagic species that primarily travels in schools. A highly sought after recreational finfish. Reported to live more than 12 years.(Source: Fishes of the Chesapeake Bay)
Bluefish (Pomatomus saltatrix) This sectioned bluefish otolith is 1 year old. The oldest bluefish aged by our surveys: ChesMMAP 2 years old, NEAMAP 5 years old.
Butterfish (Peprilus tricanthus) Otolith are a pelagic schooling species, typically found over sandy bottoms in near shore and offshore waters. Maximum age suspected to be 6.
Kingfish (Menticirrhus) Otolith are members of the Sciaenidae family and are known to live for at least 4 years.
Kingfish (Menticirrhus) This sectioned kingfish otolith is 2 years old. The oldest kingfish aged by the ChesMMAP survey was 7 years old.
Red drum (Sciaenops ocellatus) Otolith is an important recreational finfish that may travel in large schools. Red drum may live as long as 35 years.(Source: Fishes of the Chesapeake Bay)
Red drum (Sciaenops ocellatus) This sectioned red drum otolith is 8 years old. The largest red drum aged by the ChesMMAP survey was 30 years old.
Scup (Stenotomus chrysops) Otolith are abundant fishes which prefer hard-bottom and submerged structures. Scup may attain 15 years of age (Source: Fishes of the Chesapeake Bay)
Scup (Stenotomus chrysops) This sectioned scup otolith is 9 years old. The oldest scup aged by our surveys: ChesMMAP 2 years old, NEAMAP 4 years old
Sheepshead (Archosargus probatocephalus) Otolith prefer high-relief, hard-bottom areas. An excellent food fish that has been reported to live as long as 35 years. (Source: Old Dominion University's Center for Quantitative Fisheries Ecology)
Sheepshead (Archosargus probatocephalus) This sectioned sheepshead is 8 years old. The oldest sheepshead aged by the ChesMMAP survey was 26 years old.
Spot (Leiostomus xanthurus) Otolith one of the Chesapeake Bay's most important commercial and recreational species. Spot have been reported to 6 years old. (Source: Old Dominion University's Center for Quantitative Fisheries Ecology)
Spot (Leiostomus xanthurus) This sectioned spot otolith is 1 year old. The oldest spot aged by the ChesMMAP survey was 4 years old.
Striped bass (Morone saxatilis) Otolith Important recreational and commercial finfish. Females grow larger than males, and most fish older than 11 years are females, with ages exceeding 30 years reported.
Striped bass (Morone saxatilis) This sectioned striped bass otolith is 4 years old. The oldest striped bass aged by our surveys: ChesMMAP 20 years old, NEAMAP 21 years old
Summer flounder ( Paralichthys dentatus) Otolith recreationally and commercially important flat fish. Excellent food fish. Known to live at least 12 years.
Summer flounder (Paralichthys dentatus) This sectioned summer flounder otolith is 3 years old. The oldest summer flounder aged by our surveys: ChesMMAP 12 years old, NEAMAP 13 years old
Weakfish (Cynoscion regalis) Otolith a member of the family Sciaenidae that often occur in schools and frequent shallow, sandy bottom areas. Known to live at least 12 years. (Source: Fishes of the Chesapeake Bay and NEFSC)
Weakfish (Cynoscion regalis) This sectioned weakfish otolith is 2 years old. The oldest weakfish aged by our surveys: ChesMMAP 6 years old, NEAMAP 4 years old.
White perch (Morone americana) Otolith a member of the family Moronidae. White perch are ubiquitous in estuaries and freshwater ecosystems. White perch may live as long as 17 years (Source: Fishes of the Chesapeake Bay)
White perch (Morone americana) This sectioned white perch otolith is 6 years old. The oldest white perch aged by the ChesMMAP survey was 17 years old.
Winter flounder (Pseudopleuronectes americanus) Otolith the most common near-shore (shallow-water) flounder. Important U.S.commercial and recreational fisheries exist from the Gulf of Maine to the the Mid-Atlantic Bight. Winter flounder have been know to reach 15-20 years of age. (Source: NOAA NEFSC)
Winter flounder ( Pseudopleuronectes americanus) This sectioned winter flounder otolith is 3 years old. The oldest winter flounder aged by the NEAMAP survey was 19 years old.
Why is ageing fish important?
Ageing fishes is a vital part of fish stock management. Ageing is also important for the monitoring of fish populations and their reaction to environmental impacts such as fishing, natural mortality, and predation. This management will help aid in more long term monitoring and management of fish stocks to create sustainable fish stocks.
Our sample area focuses on two survey areas of the Chesapeake Bay and the Northwest Atlantic Ocean from Cape Hatteras, North Carolina to Martha’s Vineyard, Massachusetts. The Chesapeake Bay is the east coast’s largest estuary which makes it an essential body of water to monitor. This coupled with the near shore survey in the Atlantic provides sample coverage for many commercially valued species which should all be carefully monitored.
A variety of methods are used to age fish. Scales, vertebrae, spines and otoliths are a few of the hard calcified structures that are commonly used to age fish. Scales and otoliths, the fish’s ear bones, are the two most common that our group samples. Within choosing a calcified structure to read there are a variety of methods to read a process those samples. Scales can be pressed into an acetate medium where annual marks can more easily be read. These annual marks are also visible on whole otoliths and can also be further examined by sectioning the otolith. Our group has been recently working on a comparison study between scales, whole otoliths and sectioned otoliths to find which part provides a clearer more accurate read.
To further elaborate, annual marks or annuli are formed by environmental factors like water temperature is association with the change in seasons. Water chemistry, salinity and population density can also be factored into the formation of annuli. Spawning often coincides with annuli formation. Many of the fishes we sample form annuli during their spawning season.