NOAA Technical Report NMFS 7 The Feeding Ecology of Some Zooplankters That are Important Prey Items of Larval Fish Jefferson T. Turner July 1984 u.s. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Marine Fisheries Service NOAA TECHNICAL REPORTS NMFS The major responsibilities of the National Marine Fisheries Service (NMFS) are to monitor and assess the abundance and geographic distribution of fishery resources, to undern and and predict fluctuations in the quantity and distribution of these resources, and to establish levels for optimum useofthe resources . NMFS is also charged with the development and im­ plementation of policies for managing national fishing grounds, development and enforcement of domestic fisheries regula­ tions, surveill ance o f foreign fishing o ff Ullited States coastal waters, and the development and enforcement of international fishery agreements and policies. NMFS also a>sish the fishing industry through marketing service and economic analysis programs, and mortgage insurance and ycs, el construction sllbsidies. It collects, analyzes, and publishes statistics on various phases of the industry. T he NOAA T echnical Rep o rt NMFS series was es tablished in 1983 to replace two subcategories of the Technical Reports series: " Special Scit:l1 t1fic R~po rt - Fish eries " and "Circular." The series contains the following types of reports: Scientific investigations that document long-term continuing programs o f NMFS, intensive scientific reports on studies of restric ted scope, papers on applied fishery problems, technical reports of gO'neral interest intended to aid conservation and management, reports that review in cons iderable detail and at a high technical level certain broad areas of research, and technical papers o riginating in economics studies and from management investig.ations. Copi e~ o f NOAA T echnic al Report NMFS are available fr ee in li mited numbers to governmental agencies, both Federal and State. They are also available in exchange fo r other sci entific and technical publications in the marine sciences. Individ­ ual copies may be obt ai n ~d from : Publicarions Servi ces Branch (E! AI 13), National Enviro nmental Satellite, Data, and In­ formation Service, Natio nal Oceanic and Atmospheric Adminis1ration, U.S. Department of Commerce, 3300 W hitehaven St., Washington, DC 20235. NOAA Technical Report NMFS 7 The Feeding Ecology of Some Zooplankters That are Important Prey Items of Larval Fish Jefferson T. Turner July 1984 U.S. DEPARTMENT OF COMMERCE Malcolm Baldrige, Secretary National Oceanic and Atmospheric Administration John V. Byrne, Administrator National Marine Fisheries Service William G. Gordon, Assistant Administrator for Fisheries The National Marine Fisheries Service (NMFS) does not approve, rec­ ommend or endorse any proprietary product or proprietary material mentioned in this publication. No reference shall be made to NMFS, or to this publication furnished by NMFS, in any advertising or sales pro­ motion which would indicate or imply that NMFS approves, recommends or endorses any proprietary product or proprietary material mentioned herein, or which has as its purpose an intent to cause directly or indirectly the advertised product to be used or purchased because of this NMFS publication. CONTENTS Introduction. 1 Acartia .. .. .. .. .. .. ... .. .. ... .. 4 Calanus .. .. .. .. .. ... ... .. .. .. ... ... .. 5 Centropages . 7 Paracalanus ............. ................................... ............................ .......... .... 8 Pseudocalanus ............................................... .. .. .. ................................... 8 Temora ................. ...................................................................... ......... 8 Cyclopoid copepods .......................................... ........ .. .. .. .. .. ....... .. .... .. 8 Oithona ............................................................................................... 8 Corycaeus .. .. .. .. ...................................................................... ....... .. 9 Oncaea . ................................ ........... .................................................. 9 Planktonic harpacticoid copepods ......................... .................................................. 9 Copepod nauplii ..................... .. .. .. ........ ................. ................... ............ 9 Tintinnids ........ ........................................... ........ ................................. 10 Appendicularians .............. .. .. .. .. .. .. .. .. ........ ..... .. ........... .. ....... ....... 10 Marine cladocerans ....................................... ................................................ 11 Barnacle nauplii ....................... .. ................. ... ..... ................ ....... .......... 11 Gastropod larvae ................................................................. ........................ 11 Limacina ........... .............. .............. ............................. .................. ..... 12 Discussion ........... ....................... .. .. ................... ..... .. .. .. .... .. .......... 12 Acknowledgments ........................................................................ ................ 13 Literature cited ............... ........ .. ................. .. .. .. .. .. ............. ............. .. 13 Appendix tables .................. .................... ....................... ................... ....... 20-28 Figures 1. Percentages of total number of fish larvae, total number of clupeiform larvae, total number of perciform larvae, total number of pleuronectiform larvae, and total number of gadiform larvae that have been reported to feed upon various cope pod taxa ........................................................................................ 4 2. Percentages of total number of fish larvae, total number of clupeiform larvae, total number of perciform larvae, total number of pleuronectiform larvae, and total number of gadiform larvae that have been reported to feed upon various non- copepod taxa. 4 Table 1. Species of fish for which feeding habits of larvae were examined ............................................ 2-3 iii The Feeding Ecology of Some Zooplankters That are Important Prey Items of Larval Fish1 JEFFERSON T. TURNER 2 ABSTRACT Diets of 76 species of nsh larvae from most oceans of tbe world were Inventoried on tbe basis of Information In 40 pubUsbed studies. Although certaln geograpblc, size- and taxon-specinc patterns were apparent, certain zooplankton taxa appeared In tbe diets of larvae of a variety of nsb species In numerous IocaUties. Included were sb genera of calaoold copepods (Acartia. Caianus. Cenlropagts. Paracalanus. Pseudocaianus. Temora). three genera of cyclopold copepods (Corycaeus. Oilhona. Oncata). barpacticoid copepods, copepod naupUl, tintlnolds, cladoceraos of the geoera Evadne and Podo... barnacle naupUl, gastropod larvae, pteropods of tbe geous Limaclna. and appendicularlans. Literature on reeding bablts or these zooplankters reveals that most of the copepods are omnivorous, feeding upon both phytoplankton and other zooplankton. Some taxa, sucb as Calanus. Paracaiaflus. Pstudocalanus. and copepod nauplU appear to he primarily herbivorous, while others, such as Acart/a, COfllropages. Tomora. and cyclopolds exhibit broad omnlvory or carnlvory. The noncopepod zoo­ plankters are primarily niter-feeders upon pbytoplankton andlor bacteriopJankton. Despite the Importance of zooplankters In larval nsb food webs, spectnc knowledge of the reedlog ecology or many taxa 15 poor. Further, much present knowledge comes only from laboratory Investigations that may not accurately portray feeding bablts of zooplankters In nature. Lack or knowledge of tbe reeding ecology or many abundaill zooplankters, which are also Important In larval nsh food webs, precludes reaUstic understanding of pelagic ecosystem dynamics. INTRODUCTION use information on feeding of larvae only, not postlarvae.3 All but a few studies were based on examinations of gut contents of field­ It has long been Ihought that fluctuations in year class sizes are caught larvae; the few exceptions were based on studies of larvae largely dependent upon the success of fish larvae in finding feeding upon natural zooplankton assemblages. Collette (1978), necessary kinds and amounts of food (Hjort 1914). Understanding Hureau and Monod (1973), and Robins et a!. (1980) were used to the dynamics of food webs that support fish larvae requires infor­ identify taxonomic synonymies of fish species. mation not only on the kinds and amounts of food required by lar­ Lists of fish species whose larvae have been reported to eat val fish, but also of the organisms upon which larvae feed. various zooplankton taxa are presented in Appendix Tables 1-20. Although larvae of numerous fish species, particularly c1upeoids, For zooplankton taxa eaten by larvae of >5% of the total 76 fish feed directly on phytoplankton (Blaxter 1974; Lasker 1975, 1978, species, the percentages of the total number of fish, as well as 1981; Mendiola 1969, 1974). most also feed upon zooplankton, at percentages of the total number from each order (Clupeiformes, least during some stage of larval life. Since larvae of numerous Perciformes, PJeuronectiformes, and Gadiformes) that eat various species of fish may feed selectively upon certain zooplankters, zooplankters, are presented in Figures 1 and 2. which in turn may feed selectively on certain