Fish ototliths.

Image by Jackie Stent, CCE Suffolk

Ototliths removal.

NYS Fisheries Data Collection

The Fisheries Management Program of Cornell Cooperative Extension has two facets. One is the sampling program which we'll talk about below. The other is that our fisheries team processes federal and state fisheries data as well as state vessel trip reports.

Biological Sampling Program

The mission of the sampling program is to obtain raw data essential to understanding the ages and the size distributions of individual stocks of marine fish. Fieldwork provides the biological foundation for many fisheries assessments. Biological data, which is collected in the field, is used in models designed to guide management decisions and future research.

The ages of many marine fishes are determined by measuring the length of the fish and extracting the "hard parts". The hard parts used for aging include scales, ototliths and operculum.

Most fish species are aged using the scales which contain growth rings and can be aged much the same as counting rings on a tree stump. Each ring usually represents one year. Flounder, fluke, scup, black sea bass, bluefish, and striped bass are aged using the scales.

Some species of fish such as tilefish, weakfish and winter flounder can be aged by extracting otoliths (fish ear bones) from the head. Otoliths also contain growth rings. In the picture to the right you can see the small bones near the brain. Otoliths can be extracted through the gills or by cutting into the skull of the fish.The procedure of requires some practice in order to remove the delicate bone in one piece.

The operculum (gill cover) is another bone which can be removed from certain fish in order to determine the age. The Blackfish, or Tautog, is the only fish we remove the operculum from. Like scales and otoliths, the operculum also has growth rings which can be counted to determine age.

Once the scales, otoliths & operculum are collected by Cornell Fisheries Technicians, they are sent away to be aged at the North East Fisheries Science Center in Woods Hole Massachusetts or the New York State Department of Environmental Conservation. Age data is further analyzed to create growth curves for each species.


Fish Logos

Last updated July 26, 2019