Age and Size Composition of the Menhaden Catch Along the Atlantic Coast of the United States, 1956

Age and Size Composition of the Menhaden Catch Along the Atlantic Coast of the United States, 1956

Author: Fred C. June

Publisher:

Published: 1960

Total Pages: 44

ISBN-13:

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The 1956 catch of Atlantic menhaden (Breyoortia tyrannus) amounted to 766,000 tons. Apparent abundance, as measured by catch per purse-seine set, was highest in the North Atlantic Area and lowest in Chesapeake Bay. Geographical distribution of fishing effort is shown. Samples for age, size, and sex determinations were obtained from the purse-seine and pound-net catches landed from Fernandina Beach, Florida, to Portland, Maine. Age composition showed that the 1955 years class (age-1 fish) accounted for more than half of the total catch. This year class dominated the summer catches in the South Atlantic and Chesapeake Bay Areas as well as the fall catches in North Carolina, while the 1954 year class (age-2 fish) dominated in the Middle Atlantic Area, and the 1951 year class (age-5 fish) dominated in the North Atlantic Area. Fish of the dominant year class in each of these areas were smaller in 1956 than in the previous year.


Microhematocrit as a Tool in Fishery Research and Management

Microhematocrit as a Tool in Fishery Research and Management

Author: Stanislas F. Snieszko

Publisher:

Published: 1960

Total Pages: 1068

ISBN-13:

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Abstract: The micro method of hematocrit is rapidly replacing red cell counts in clinical hematology. Observations were made on the value of this method in routine hematological examination of trouts. Under the conditions of data collection, the normal hematocrit values for brook trout were 45 to 50, for brown trout 39 to 44, and for rainbow trout 45 to 53. There was a close correlation between the hematocrits, red cell counts and hemoglobin. The commercial heparinized capillaries, while excellent for human blood, tend to give somewhat higher readings (7 to 18 percent) with trout, due to incomplete prevention of blood coagulation. The procedure as applied to trout is described in detail.