The Biology and Conservation of the Blue Crab, Callinectes sapidus Rathbun

39 pages, illustrations, map

Conserving our salt-water fisheries: work of the Virginia Fisheries Laboratory

Even the casual visitor to many of our small Tidewater Virginia fishing communities will see signs of diminishing prosperity. A prosperous era has been succeeded by a period of lower economic and social levels. What are the underlying causes of this declining trend? In facing this problem, so broad in its scope and so serious in its effect, the Virginia Fisheries Laboratory has, during the past year, effected an organization for analyzing conditions in our commercial fisheries and for disseminating facts about them and the need for their conservation

Seafoods : their wartime role in maintaining nutritional standards

Recent years have witnessed improved dietary changes, due largely to an increase in knowledge of nutrition and to a wide dissemination of this knowledge. Since about 1915 there has been a significant upward trend in· the consumption of milk, green leafy vegetables, tomatoes, and citrus fruits-the so-called protective foods-all of which are extremely rich in those nutrients that are often deficient in low-cost diets. The total weight of food consumed per person per year has remained fairly constant, but there has been a downward trend for meats, grain products, and potatoes, and the use of the protective foods has been increasing. The proportion of calories derived from these latter sources has approximately doubled since the beginning of the century. From.a health standpoint this trend is most encouraging, yet the proportion of calories derived from meats, grains, and mature legumes is still over 70 per cent. Probably half the food calories should be derived from milk and milk products, fruits, vegetables, and eggs. Now, wartime restrictions have changed what were fairly well-balanced family diets into diets deficient not only in certain minerals and vitamins but also in animal proteins essential for the maintenance of normal health. Fresh seafoods, since these are not rationed, should be seriously considered as a source of the indispensable animal proteins

Observations on the Conservation of the Chesapeake Blue Crab, Callinectes sapidus Rathbun

It is a matter of common knowledge among conservationists that the blue crab supply of the Chesapeake is rapidly declining, being reduced from a level of about 17 millions in 1931 to that of about 10 million crabs in 1937. (Md. Rept. 1937). Numerous explanations have been advanced to account for this decline. One outstanding reason is the taking of such large numbers of sponge (berried) crabs and mated female crabs, a practice which undoubtedly reduces the potential supply of young crabs for the ensuing year. Another menace to the survival of the blue crab lies in the way in which soft crabs are handled in the industry. The current methods of transporting and holding crabs on shedding floats are responsible for the loss of a very significant percentage of the total numbers taken. From a standpoint of practical conservation, no single one of our Chesapeake commercial fisheries merits more immediate attention than the blue crab fishery. This paper embodies the results of observations made on the current practices followed by the industry in handling crabs, and the effect of these practices on survival rate from a conservation viewpoint

Future of the Virginia Oyster Industry

CHESAPEAKE BAY has long been famous for its oysters. Shared by Maryland and Virginia, this natural resource contributes greatly to the economic life of about thirty Tidewater counties. Virginia oyster grounds extend approximately half way up the bay and reach far up the numerous tributaries. In addition, there are thousands of acres of oyster grounds on the Sea Side of the Eastern Shore. Despite the magnitude of the acreage adapted for growing oysters, comparatively little effort has been made to find out just how valuable the industry is to the state or to explore its possibilities for development. Federal statistics indicate that Virginia ranks as the No. 1 oyster-producing state, the yield amounting to at least 5,000,000 bushels annually. Still, it is recognized that the state\u27s oyster grounds are capable of a much higher level of production than is witnessed toda

Variations in the phosphorus content of estuarine waters of the Chesapeake Bay near Solomons Island, Maryland

Studies by Cowles and Brambel (1938), Newcombe and Lang (1939), and Newcombe, Horne and Shepherd (1939) have provided information on the quantitative methods for estimating inorganic phosphorus and, also, on the vertical and horizontal distribution of this nutrient substance in the waters of the Chesapeake Bay...

Observations on the alkalinity of estuarine waters of the Chesapeake Bay near Solomons Island, Maryland

Kolthoff (1926) without particular reference to sea water has defined buffer capacity (alkalinity, in the case of added strong base) of a solution quantitatively as the number of equivalents of added strong base or strong acid required to change the pH of one liter of solution one unit. Buch, in 1930, redefined this concept with reference to sea water as the number of moles of carbonic acid which must be added to one liter of the water in order to change its pH by one unit

Methods of Hatching Eggs of the Blue Crab

The blue crab, Callinectes sapidus Rathbun, is the only important marketable crustacean in Chesapeake Bay. While this body of water may be regarded as a center of its numerical distribution, blue crabs in the United States range from Cape Cod south to Texas. Their economic importance is indicated by records of the Federal Government which report for the four-year period 1936-39, an annual average of over 82 million hard crabs valued at about $526,000 from Virginia and 56 million worth about$382,000 from Maryland. Soft crab catches in the two states during this period were approximately the same, amounting in each case to over 10 million crabs per year valued at about $210,000. The commercial value of this fishery, shared by Maryland and Virginia, to local tidewater communities warrants careful examination of the economic and production trends in their relation to sound conservation practice. In view of the need for information on the early development of the blue crab, studies were begun at the Virginia Fisheries Laboratory in 1940. An effort was made to develop a hatching technic for crab eggs under laboratory conditions that might open the way for large scale application under natural conditions. During the summer of 1941, the crab work was extended and intensified in view of reports of a serious shortage of soft crabs, particularly in Maryland. Aiming to answer questions of practical value to the industry and to crab conservation, studies on the hatching of eggs and experiments on water conditions as they affect hatching and survival of crab larvae were stressed