''' "^ V^ V. .V i -t_^o r V'^ ^ ^ ' ^ T^ T ^Ui^_i: r} ! / — FOOD HABITS OF GEORGES BANK HADDOCK Marine Biological Laboratory MAR 26 labS WOODS HOLE, iViASS. SPECIAL SCIENTIFIC REPORT- FISHERIES No. 165 UNITED STATES DEPARTMENT OF THE INTERIOR FISH AND WILDLIFE SERVICE EXPLANATORY NOTE The series embodies results of investigations, usually of restricted scope, intended to aid or direct management or utilization practices and as guides for administrative or legislative action, it is issued in limited quantities for official use of Federal, State or cooperating agencies and in processed form for economy and to avoid delay in publication United States Department of the Interior, Douglas McKay, Secretary Fish and Wildlife Service, John L. Farley, Director FOOD HABITS OF GEORGES BANK HADDOCK By Roland L. Wigley Fishery Research Biologist Special Scientific Report- -Fisheries No 165 Washington, D. C. January 1956 ABSTRACT Stomach contents of 1, 287 haddock, each major food group in the diet was as - Melanogrammu s aeglefinu s, from Georges follows: Crustaceaiisracfa 33.1oo.i percent; Mol-i\ Bank were analyzed qualitatively and quan- lusca - 17 5 percent; Echinodermata - titatively. These specimens were caught 14 6 percent; Annelida - 9.9 percent; and by means of otter trawls during the period Pisces - 1.9 percent. April 1953 to February 1954. Canadian biologists have reported that The haddock's diet consisted principally haddock on the offshore Nova Scotian banks of sedentary or slow moving invertebrate fed predominately on fish. On Georges animals; benthic and epi-benthic forms pre- Bank crustaceans were found to be the pri- dominated. Small organisms were especially mary food; fish constituted less than 2 common in the food, presumably because the percent of the food volume . Other notable haddock's rather small mouth precludes tak- differences were disclosed in the dietary ing large items The percentage volume of composition of specimens collected from various parts of Georges Bank itself. CONTENTS Page Introduction 1 Methods ......................................... 2 Results .................... 6 Food-type areas , 11 Georges Basin 11 Northeast Peak 13 Southeast Part 16 Evaluation of foods , . 16 Seasonal variation ,.,,,,.... 18 Size of food organisms ,.,..........,.,,.: 21 Acknowledgments , . 21 Summary ...... :.............,...,.,.... 22 Literature cited , . ..,...,. 22 Appendix: A list of organisms found in stomachs of Georges Bank haddock during this report period ......... 24 LIST OF ILLUSTRATIONS Figure 1 . Collection stations and food-type areas on Georges Bank 3 Figure 2 . Regression of body length on stomach weight 7 Figure 3 . Composition of haddock stomach contents expressed as percentage volume . 9 Figure 4. Histograms of haddock stomach contents for each food- type area , ..,..,....,.....,....., 14 . FOOD HABITS OF GEORGES BANK HADDOCK invertebrate fauna in The Georges Bank haddock ( Melanogrammus sampling the bottom aeglefinus Linnaeus) fishery yields approximate- the areas where stomach samples are ly 94 million pounds o± fish annually. Production taken in order to relate the food captured of this weight of fish requires many more times by haddock with the presence of food organ- as much weight m food organisms . The fact isms. that the total production of haddock does not vary widely from year to year indicates a This report presents the results of the fairly reliable and constant supply of food. Is first year's study of haddock food habits. this food supply reliable? Is it always com- posed of the same species of organisms? Does European biologists Jmve long been in- it vary from season to season? Does it differ terested in the food habits of haddock and from one part of the bank to another? Is it they have carried out many investigations consistent from one year to another or are on this subject. Food studies of haddock there violent changes which affect the abundance taken from waters surrounding the British of new year classes as they begin their demer- Isles have been particularly numerous. sal existence? Are the movements of the had- Macintosh (1874), Trechman (1888), Smith dock over the bank influenced by variations in (1892), Scott, A. (1896), Scott, T. (1902), the available food supply? Are the haddock Todd (1905, 1907), Carr (1907, 19D9), selective in their food habits or do they take Bowman (1923), Ritchie (1937), and Jones anytking they can catch? (1954) are the most important contributors. They found echinoderms, moUusks, Georges Bank haddock are the fastest crustaceans, annelids, and fish to be the growing m the world. Is this the result of common foods of haddock in that area more abundant or more nutritious food? Some Ritchie (loc. cit.) made quantitative analyses of year classes grow faster than others . Is this of the stomach contents from thousands related to variations in available food? What haddock . His work is the most thorough species of fish compete with haddock for the study of haddock food habits that has been same foods and how detrimental is this com- made . Haddock from Scandinavian waters, petition? as xenorted by Idelson (1929), Blegvad (1917), and Poulsen (1928), were found to These are some of the questions which subsist largely upon mollusks, echinoderms, the food habits project of the North Atlantic annelids, and crustaceans . Food of haddock Fishery Investigations is attempting to answer from Icelandic waters has been reported by The initial work m this study is the examina- Thompson (1929), Brown and Cheng (1946), tion and analysis of stomach contents collected and Fridriksson and Timmermann (1950) primarily on commercial trawlers. No ex- Echinoderms and annelids were the pre- perimental design could be followed during dominant food Items; crustaceans, mollusks, this stage of the study when observers were and fish occurred less frequently. collecting stomachs wherever the fishermen happened to fish North American biologists have carried out comparatively few investigations per- The second stage of this study calls for taining to haddock food habits , Haddock (1) sampling according to plan using the from Nova Scotian waters have been exam- Albatross in to fill in where samples from ined by Willis (1890), Needier (1929), -commercial trawlers are lacking; and (2) Vladykov (1933), and Homans and Needier . (1944). The-principal foods were fish, ech- of Cape Cod, Massachusetts, known as inoderms, moUusks, and annelids . The work Georges Bank. Most of the samples were by Homans and Needier (loc cit.) is the most taken from the northern and eastern parts complete food habit study of haddock from of the bank, which are the areas most heavily North American waters. Specimens from the fished by the commercial haddock-fishing coastal waters of Maine were found by Atwood fleet . The location at which each collection (1865) and Kendall (1898) to feed chiefly on was made is plotted on the chart shown in brittle- stars, sea urchins, andmollusks. figure 1 . Specific information concerning From haddock taken in coastal waters of each collection is listed m table 1 . All southern New England, Verrill (1871, 1873 = specimens were collected with standard otter Baird 1889) reported moliusks, echinoderms, trawl gear operated from commercial fishing crustaceans, and annelids trawlers and the research vessel Albatross lU. Bigelow and Schroeder (1953), in refer- This report is based upon the content ence to haddock inhabiting the Gulf of Maine analysis of 1, 287 haddock stomachs from 38 (Georges Bank included), state that large collections taken during the 1 1 -month period crustaceans, a great variety of gastropods April 1953 to February 1954. An attempt and bivalve moliusks, worms, starfish, sea was made to collect stomachs regularly urchins, sand dollars, brittle -stars, and sea throughout the year . However, samples are cucumbers all enter regularly into the had- lacking for August and November because dock's dietary, Homans and Needier (1944) commercial fishing"within the study area was examined 179 small (10 - 30 centimeters) too light to afford an opportunity to obtain haddock from Georges Bank. The stomach samples contents consisted entirely of the shell-less gastropod Aeolis papillosa Stomach contents Haddock utilized m this study ranged in of 1, 500 haddock, also taken fiom Georges size from 14 to 75 centimeters In length. The Bank, were examined by Clapp (1912) . Sixty- length -frequency distribution of these fish is eight species of moliusks are the only items listed in table 2 . Most of the specimens were listed. Clapp also observed that in certain between 30 and 75 centimeters, which is the parts of the noithwest portion of Georges same size range of haddock captured by com- Bank the haddock feed heavily upon annelid mercial trawlers . Inasmuch as the smaller worms o specimens, those between 14 and 30 centi- meters, were not commonly caught by It is apparent from the foregoing litera- standard gear, few specimens within that ture review that a comprehensive study of size range are represented. the food habits of haddock from Georges Bank - one of the greatest haddock producing areas Because detailed analysis of the stomach - in the world has never been undertaken . It contents was required, the stomachs were is the purpose of the present report to record collected at sea and brought to the laboratory the kinds of orgamsms Georges Bank haddock for examination . Aboard ship, stomachs prey upon and, more specifically, to evalu- were removed from haddock and placed in a ate the relative