Oceanography of the Mid-Atlantic Bight 



in Support of ICNAF 



Septeniber-Deceinber 1967 



Vincent L. Whitcomb ' 



INTRODUCTION 



The northwest Atlantic is one of the most 

 important commercial fishing areas in the 

 world. Fishing fleets of many nations return 

 annually to this region to harvest almost 4 

 billion pounds of fish and mollusks. The catches 

 of these fleets contribute significantly to their 

 nations' economy. These extensive fishing op- 

 erations cannot, however, continue indefinitely 

 without some management to protect against a 

 depletion of resources. Recognizing the need 

 for such management, 15 nations that fish in 

 the northwest Atlantic have formed the Inter- 

 national Commission for the Northwest At- 

 lantic Fisheries (ICNAF). The goals of 

 ICNAF are to understand the natural fluctua- 

 tions in abundance of fish stocks, to assess the 

 eff"ects of commercial fishing, and to devisfe 

 guidelines for the international management of 

 fishing. operations. The member nations include 

 Canada, Denmark, France, Federal Republic of 

 Germany, Iceland, Italy, Japan, Norway, Po- 

 land, Portugal, Romania, Spain, United States, 

 Union of Soviet Socialist Republics, and the 

 United Kingdom. 



A primary area for ICNAF investigation is 

 Georges Bank. This area supports one of the 

 richest and most highly exploited fisheries in 

 the world/ The fish species of greatest interest 

 in this area are haddock, herring, and silver 

 hake. To understand the ecology of these 

 species, a detailed investigation of their dis- 

 tribution, relative abundance, and growth and 

 mortality rate in relation to environmental 

 conditions is required. Such an investigation 

 entails frequent measurements over the life 

 cycle of each species and requires a multi-ship 



1. U.S. Coast Guard Oceanographic Unit. Washington, D.C. 

 20390. 



operation. The ICNAF members recommended 

 that the USA and the USSR devise a plan for 

 investigating the area, and indicate the re- 

 sources that could be made available for the 

 project. The plan was submitted in 1966, and 

 after revision, accepted in 1967. The area of 

 coverage was expanded to include the Mid- 

 Atlantic Bight to the south (to 35°00'N) and 

 the Gulf of Maine to the north of Georges Bank 

 (to41"31'N). 



The Bureau of Commercial Fisheries is the 

 United States representative agency to ICNAF. 

 Under the Northwest Atlantic Fisheries Act 

 of 1950 (16USC981) the United States Coast 

 Guard is charged with cooperating with BCF in 

 matters relating to ICNAF. The role of the 

 Coast Guard in the ICNAF program is to col- 

 lect and process data on the seasonal variations 

 of the physical and chemical oceanography of 

 the area being studied. The initial cruise per- 

 formed in February 1967 (ICNAF 67-1) was 

 to test various types of equipment for measur- 

 ing currents on the Georges Bank. The re.sults 

 of this cruise were inconclusive due to the 

 severe environmental conditions encountered. 

 The first Coast Guard ICNAF survey cruise 

 was made in September 1967 (ICNAF 67-2, 

 fig. 1) by the USCGC EVERGREEN (WAGO 

 295) in conjunction with a groundfish survey 

 conducted in the same area by the U.S. R/V 

 ALBATROSS IV (of BCF) and the USSR's 

 R/V ALBATROSS. A second cruise the area 

 was conducted by USCGC EVERGREEN in 

 December 1967 (ICNAF 67-3, fig. 2). The 

 purpose of the two Coast Guard cruises was to 

 obtain data on the vertical and horizontal dis- 

 tribution of temperature, salinity, dissolved 

 oxygen and chlorophyll. The results are pre- 

 sented in this report. 



