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Lorenzo Ciannelli

Lorenzo Ciannelli photo

Discipline: Ocean Ecology and Biogeochemistry
Office: Burt 202
Phone: 541-737-3142
Fax: 541-737-2064


Fisheries oceanography, spatial ecology, fish early life stages, statistical analysis of catch and survey data

Research Interests

My primary research focus is on fisheries oceanography and marine ecology. I study the causes of temporal and spatial variation of marine populations, as well as the management implications of the factors involved. A substantial fraction of my work revolves around early life stages of fish, as in marine organisms, spatial and temporal variability at the population level is closely linked to events that occur during the very first few months or years of life. I have also worked extensively on the ecology of adult stages, predator-prey trophic interactions in marine ecosystems, and on dispersal and distribution patterns of scyphozoa jellyfish.

I particularly value merging the ecological and quantitative disciplines to study processes that affect the dynamics of marine populations in space and time. Thus, I work with modelers, statisticians, and fisheries biologists from both academic and management institutions to tackle practical problems that interface between ecology and management. I actively search for new methodologies from other disciplines that could be used to address practical problems in fisheries ecology. For example, many of my research investigations have required the development or application of principles from terrestrial ecology.


Current Research

Below, I give examples of three ongoing projects and their eco-management implications.

1)    Dispersal pathways and connectivity

Spatial patterns during the pelagic phase of fish early life-history stages are important to quantify the exchange of individuals among different aggregations in a population (i.e., genetic connectivity) and between spawning and juvenile nursery areas (i.e., ontogenetic connectivity). Dispersal and connectivity are particularly interesting topics for temperate and subarctic marine fishes, which the expectation is to have longer larval pelagic duration and less genetic diversity due to greater exchange of individuals subject to extensive passive drifts. However, contrary to these expectations, evidence accumulated to date indicates that even subarctic populations can have a high degree of genetic structure, but that the mechanisms that promote and maintain it are yet to be understood. In a recent study, Ciannelli et al (2010) analyzed the vertical and horizontal distribution of Atlantic cod (Gadus morhua) eggs in relation to small-scale circulation and water column hydrography in a costal location of southern Norway. We documented that cod eggs were found in greater abundance (1) in shallow water layers, which on average flow up the fjord (away from the open ocean), and (2) in the inner portion of the fjord, which is subject to lower current speeds compared to the outer fjord or the mouth of the fjord. Eggs were found to be neutrally buoyant at shallow depths – a trait that also favors local retention, given the local circulation. The same patterns held during two environmentally contrasting years. Our results importantly suggest that the observed population structure of Atlantic cod is favored and maintained by a balance between water circulation, egg characteristics, and reproductive biology of adults, and is robust against variation of hydrographic features.

2)    Geographic and environmental attributes of fish spawning aggregations

To spawn, many marine fish species return to their natal site or to a nonnatal but repeated site. This remarkable adaptation allows individuals to increase their fitness by placing the progeny in a seemingly successful location. The selection of a spawning site is the end product of several bio-physical constraints to which species are subject through their life cycle, the most prominent being the survival of the offspring, encounters with potential mates, and temporal consistency of the site’s biophysical attributes. At a regional scale, spawning sites can be characterized by a combination of environmental attributes (e.g., temperature, salinity, geostrophic velocity), and geographic attributes (e.g., proximity to a bank, sill, canyon mouth). Geographically-determined spawning locations are fixed over time, while environmentally-driven locations may be labile. The degree to which species spawning sites are characterized by either fixed or labile attributes may depend on the species life history strategies, thus begetting the question of whether we can make any generalizations across species for how their spawning sites are selected. We have proposed a conceptual framework to link species’ spawning strategies with its life history traits. Specifically, we hypothesize that the home range of the adult stages (i.e., resident vs. migrant species), their social structure (i.e., schooling vs. solitary) and the feeding behavior of the larval stages (piscivory vs. zooplanktivory) are traits that correlate with the degree to which spawning sites are either geographically or environmentally fixed. We have examined case studies from several contrasting species, including Atlantic and Pacific cod (coastal and oceanic subpopulations), Alaska walleye pollock, Pacific sardine, northern anchovy, and three species of Mediterranean tuna. Besides having broad scientific appeal, the spatio-temporal characterization of spawning locations has also ecological and applied implications. In commercial species, for example, the spawning site is often the primary harvest and assessment location. Further, because the spatial distribution of fish is linked to their spawning locations, a characterization of the biophysical attributes of spawning sites provide insight on the lability of a species geographic range.


3)    Density-dependent and density-independent habitat selection

Species can distribute over space following environmental preferences, to optimize the use of spatially heterogeneous resources, and in relation to their own density, to reduce intraspecific competition. Typically, these two sources of variability have been studied in isolation – an unfortunate circumstance as the two processes very likely interact (i.e., the outcome cannot be attributed to either process in isolation). In a recent study (Ciannelli et al In press) we examined the spatial distribution of Arrowtooth flounder (Atheresthes stomias) in the Bering Sea, and showed that the expected increase in habitat extension during years of high population abundance, is in fact curtailed/enhanced during cold/warm years. The analytical framework developed to address our study gave statistical significance to the synergistic effect of abundance and temperature on arrowtooth flounder distribution, and can be readily applied to other study systems to address similar ecological questions.


1993 Laureate in Biology, Universita’ Degli Studi di Napoli "Federico II", Italy. Dissertation: Comportamento trofico di Dexamine spinosa (Montagu 1813) (Crustacea, Amphipoda) in praterie a Posidonia oceanica dell’isola d’Ischia, Golfo di Napoli (Italia). Tesi di Laurea. Universita’ degli Studi di Napoli, pp 210. 2002 Ph.D. in Aquatic Fishery and Sciences, University of Washington, School of Aquatic and Fishery Sciences (SAFS), Seattle, WA. Dissertation: Cross-scale analysis of the Pribilof Archipelago ecosystem, southeast Bering Sea, with a focus on age-0 walleye pollock, Theragra chalcogramma. Ph.D. Thesis. University of Washington, pp 192.


    • Connectivity between Greenland halibut spawning and nursery locations in the southeast Bering Sea. Ciannelli L., Duffy-Anderson J., Matarese A., Bailey K., Stabeno P., Wilderbuer T.
      • integrate field investigations and modeling analyses to characterize spawning locations and early life drift pathways of Greenland halibut (Reinhardtius hippoglossoides) in the southeast Bering Sea.
      • management implications


    • Modeling growth and survival of early life-stages of Pacific cod (Gadus macrocephalus) in response to climate-related changes in sea ice conditions in the eastern Bering Sea. Ciannelli L., Laurel B, Hurst T, Stoner A, Davis M, Behrenfeld M.
      • integrate experimental investigations and spatially-explicit bioenergetics modeling to characterize the habitat quality of Pacific cod in the Barents Sea during periods with contrasting climate conditions
      • community and management


    • Spatial survival of age-0 cod in the Barents Sea. Ciannelli L., Digsør G., Bogstad B., Ottersen G., Chan K.S., Stenseth NC, Gjøsæter H
      • characterize the spatial variability of age-0 cod (Gadus morhua) survival in the Barents Sea based on changes of spatial distribution during the first winter of life
      • ecological and management implications


    • Egg distribution, bottom topography and small-scale population structure in a coastal marine system south of Norway. Ciannelli L., Moland E., Knutsen H., Stenseth N.C.
      • study the causes of small scale population structure in costal cod (Gadus morhua) along the Skagerrak coast (south of Norway)
      • evolutionary implications


  • Phenological and geographical patterns of walleye pollock spawning aggregations in the Gulf of Alaska. Ciannelli L., Bailey K.M., Chan K.S., Stenseth N.C.
    • study the processes affecting timing (phenology) and location (geography) of walleye pollock (Theragra chalcogramma) spawning in the Gulf of Alaska
    • ecological and management implication
  • Climate variability and jellyfish dynamics in the Bering Sea. Brodeur R., Decker M.B., Hunt G., Bond N., Purcell J., Stabeno P., Ciannelli L., Chan K.S., Ladd C.
    • examine causes of temporal and spatial variability of jellyfish in the Bering Sea over contrasting climate periods
    • ecosystems implications


1)    Ciannelli L, Bartolino V, Chan KS (in press) Nonadditive and nonstationary properties in the spatial distribution of a large marine fish population. Proceeding Royal Society London B

2)    Ciannelli L, Fisher JAD, Skern-Mauritzen M, Hunsicker ME, Hidalgo M, Frank KT, Bailey KM. (In revision) Theory, consequences and evidence of eroding population spatial structure in harvested marine fishes. Marine Ecology Progress Series

3)    Hidalgo M, Rouyer T, Bartolino V, Cervino S, Ciannelli L, Massuti E, Jadaud A, Saborido-Rey F, Durant JM, Santurtun M, Pinero C, Stenseth NC (2012) Context-dependent interplays between truncated demographies and climate variation shape the population growth rate of a harvested species. Ecography

4)    Bartolino V, Ciannelli L, Spencer P, Wilderbauer T, Chan KS (2012) Scale-dependent depletion of natural populations. Marine Ecology Progress Series 444: 251-272

5)    Chen K, Chan KS, Bailey KM, Ciannelli L, Aydin K (2012) A probabilistic cellular automata approach for predator-prey interactions of arrowtooth flounder (Atheresthes stomias) and walleye pollock (Theragra chalcogramma) in the eastern Bering Sea. Canadian Journal of Fisheries and Aquatic Sciences 69(2): 259-272

6)    Hunsicker, M, Ciannelli L, Bailey KM, Buckel J, White W., Link J, Essington T, Gaichas S, Anderson T, Brodeur RD, Chan, KS, Chen K, Englund G, Frank K, Freitas V, Hixon M, Hurst T, Johnson D, Kitchell J, Reese D, Rose G, Sjodin H, Sydeman W, van der Veer H, Vollset K, Zador, S (2011) Functional responses and scaling in marine predator-prey interactions: contemporary issues and emerging concepts Ecology Letters 14(12): 1288-1299

7)    Auth TD, Brodeur RD, Soulen HL, Ciannelli L, and Peterson WT (2011) The response of fish larvae to decadal changes in environmental forcing factors off the Oregon coast. Fisheries Oceanography 20(4): 314-328

8)    Laurel B, Hurst T, Ciannelli L (2011) An experimental examination of temperature interactions in the 'match-mismatch' hypothesis for Pacific cod larvae. Canadian Journal of Fisheries and Aquatic Sciences 68(1), 51-61.

9)    Bartolino V, Ciannelli L, Bacheler NM, Chan KS(2011) Ontogeny and sex disentangle density-dependent and density-independent spatiotemporal dynamics of a marine fish population Ecology92(1), 189-200

10) Liu H, Ciannelli L, Decker MB, Ladd C, Chan KS (2011) Shifts in jellyfish distribution relative to large-scale climate variability in the eastern Bering Sea: a new approach to analyzing zero-inflated spatio-temporal data. Journal of Agricultural, Biological and Environmental Statistics 16(2): 185-201

11) Bailey KM, Ciannelli L, Hunsicker M, Rindorf A, Neuenfeldt S, Möllman C, Guichard F, and Huse G (2010) Comparative analysis of marine ecosystems: workshop on predator–prey interactions. Biology Letters 6(5), 579-581

12) Hurst T, Laurel B, Ciannelli L (2010) Ontogenetic patterns and temperature-dependence of growth rate in early life stages of Pacific cod (Gadus macrocephalus). Fishery Bulletin 108: 382-392

13) Sohn D, Ciannelli L, Duffy-Anderson J (2010) Distribution and drift pathways of Greenland halibut (Reinhardtius hippoglossoides) early life stages in the Bering Sea. Fisheries Oceanography 19(5): 339-353

14) Ciannelli L, Knutsen H, Moland E, Espeland SH, Asplin L, Jelmert A, Knutsen JA, Stenseth NC (2010) Small-scale genetic structure in a marine population in relation to water circulation and egg characteristics. Ecology 91(10): 2918-2930

15) Bacheler NM, Ciannelli L, Bailey KM, Duffy-Anderson JT  (2010) Spatial and temporal patterns of walleye pollock spawning in the eastern Bering Sea inferred from egg and larval distributions. Fisheries Oceanography 19(2): 107-120

16) Brander K, Botsford L, Ciannelli L, Fogarty M, Heath M, Planque B, Shannon L, Wieland K (2010) Human impacts on marine ecosystems. In: Barange M, Field JG, Harris RP, Hofmann EE, Perry IR, Werner F (Eds) ‘Marine ecosystems and global change’. Oxford, Biology

17) Bacheler NM, Bailey KM, Ciannelli L, Bartolino V, Chan KS (2009) Density-dependent, landscape, and climate effects on spawning distribution of walleye pollock Theragra chalcogramma. Marine Ecology Progress Series 391: 1-12 (Feature article)

18) Hidalgo M, Massutí E, Guijarro B, Moranta J, Ciannelli L, Lloret J, Oliver P, Stenseth NC (2009) Population effects and life-history traits changes under phase transitions induced by long-term fishery harvesting: European hake off the Balearic Islands. Canadian Journal of Fisheries and Aquatic Sciences 66 (8): 1355-1370

19) Llope M, Chan KS, Ciannelli L, Reid PC, Stige LC, Stenseth NC (2009) Effects of environmental conditions on the seasonal distribution of phytoplankton biomass in the North Sea. Limnology & Oceanography 54(2): 512-524

20) Brodeur RD, Decker MB, Ciannelli L, Purcell JE, Bond NA, Stabeno PJ, Acuna E, Hunt GL Jr (2008) Rise and fall of jellyfish in the eastern Bering Sea in relation to climate regime shifts. Progress in Oceanography 77:103–111

21) Ciannelli L, Fauchald P, Chan KS, Agostini VN, Dingsør GE. (2008) Spatial fisheries ecology: recent progress and future prospects. Journal of Marine Systems. 71: 223–236

22) Litzow, M., Ciannelli L. (2007) Oscillating trophic control induces community reorganization in a marine ecosystem. Ecology Letters 10: 1124–1134

23) Ciannelli L, Bailey K, Chan KS, Stenseth NC (2007) Phenological and geographical patterns of walleye pollock spawning in the Gulf of Alaska. Canadian Journal of Aquatic and Fisheries Sciences 64:713-722

24) CiannelliL, Dingsør G, Bogstad B, Ottersen G, Chan KS, Gjøsæter H, Stiansen JE, StensethNC. (2007) Spatial anatomy of species survival rates: effects of predation and climate-driven environmental variability. Ecology 88: 635-646

25) Dingsør G, CiannelliL, Chan KS, Ottersen G, StensethNC. (2007) Density dependence and density independence during the early life stages of four marine fish stocks. Ecology 88: 625-634

26) Knutsen H, Olsen EM, Ciannelli L, Espeland S, Knutsen JA, Simonsen JH,Skreslet S, Stenseth NC. (2007) Egg distribution, bottom topography and small-scale population structure in a coastal marine system. Marine Ecology Progress Series 333: 249-255

27) Stige L.C., Stave J., Chan K.-S., Ciannelli L., Pettorelli N., Glantz M., Herren H. R. & Stenseth N. C. (2006) The effect of climate variation on agro-pastoral production in Africa. Proceedings of the National Academy of Sciences, USA 103: 3049-3053.

28) Stenseth N.C., Llope M., Anadón R., Ciannelli L., Chan K.S., Hjermann D.Ø., Bagøien E., Ottersen G. (2006) Seasonal plankton dynamics along an off-coast gradient. Proceedings of the Royal London Society B, 273: 2831-2838.

29) Bailey K.M.,  Ciannelli L., BondN.A., BelgranoA., and StensethN.C. (2005) Recruitment of walleye pollock in a complex physical and biological ecosystem:  a new perspective. Progress in Oceanography 67: 24-42

30) Ciannelli L., Chan K.S., Bailey K.M., Belgrano A. and N.C. Stenseth. (2005) Climate change causing phase transitions of walleye pollock (Theragra chalcogramma) recruitment dynamics. Proceedings of the Royal London Society B 272:1735-1743

31) Ciannelli L., Hjermann D.Ø., Lehodey P., Ottersen G., Duffy-Anderson J.T. and N.C. Stenseth. (2005) Climate forcing, food web structure and community dynamics in pelagic marine ecosystems. Invited chapter in: ‘Aquatic Food Webs: an ecosystem approach’. Belgrano A., Scharler U., Dunne J., and R. Ulanowicz (Editors). Oxford University Press. Pp 143-169

32) Porter S.M, Ciannelli L., Hillgruber N., Bailey K.M., Chan K.S., Canino M.F., Haldorson L.J. (2005) Analysis of factors influencing larval walleye pollock Theragra chalcogramma feeding in Alaskan waters. Marine Ecology Progress Series 302: 207-217

33) SwartzmanG., Winter A., Coyle K., Brodeur R, BuckleyT., CiannelliL., HuntH., IanelliJ., and A. Macklin. (2005) Relationship of age-0 pollock abundance and distribution around the Pribilof Islands, to other shelf regions of the eastern Bering Sea. Fisheries Research 74 (1-3): 273-287

34) Duffy-AndersonJ.T., BaileyK., CiannelliL., Cury P., BelgranoA. and Stenseth N.C. (2005) Phase-transitions in marine fish recruitment processes. Ecological Complexity 2: 205-218

35) Winter A., Swartzman G. and Ciannelli L. (2005) Early- to late-summer population growth and prey consumption by age-0 pollock, in two years of contrasting pollock abundance near the Pribilof Islands, Bering Sea. Fisheries Oceanography 14(4): 207-320

36) Ciannelli L., and Bailey K.M. Landscape dynamics and underlying species interactions: the cod-capelin system in the Bering Sea. (2005) Marine Ecology Progress Series 291: 227-236

37) Ciannelli L., Chan K.S., Bailey K.M., and N.C. Stenseth. (2004) Nonadditive effects of the environment on the survival of a large marine fish population. Ecology 85(12): 3418-3427

38) Ciannelli, L., Brodeur, R.D., and J.M. Napp. (2004) Foraging impact of age-0 walleye pollock (Theragra chalcogramma) around a frontal structure in the southeast Bering Sea. Marine Biology 144: 515-526.

39) Ciannelli, L., Robson, B.W., Francis, R.C., Aydin, K., and R.D. Brodeur. (2004) Boundaries of open marine ecosystems: an application to the Pribilof Archipelago, southeast Bering Sea. Ecological Applications14: 942-953

40) Duffy-Anderson,J.T., Ciannelli,L., Honkalehto, T., Bailey, K. M., Sogard, S.M., Springer, A.M., and T.W. Buckley (2003). Distribution of Age-1 and Age-2 Walleye Pollock in the Gulf of Alaska and Eastern Bering Sea: Sources of Variation and Implications for Higher Trophic Levels. P. 381-394. ‘The Big Fish Bang’ Proceedings of the 23rd Larval Fish Conference, Institute of Marine Research, Bergen

41) Bailey, K.M., Ciannelli, L., and V.N. Agostini. (2003) Complexity and constraints combined in hybrid models of recruitment. P. 293-302. ‘The Big Fish Bang’ Proceedings of the 23rd Larval Fish Conference, Institute of Marine Research, Bergen

42) Ciannelli, L., Paul, A.J., and R.D. Brodeur (2002) Regional, interannual, and size-related variation of age-0 walleye pollock (Theragra chalcogramma) whole body energy content around the Pribilof Islands, Bering Sea. Journal of Fish Biology  60:1267-1279

43) Ciannelli, L., Brodeur, R.D., Swartzman, G.L., and S. Salo. (2002) Physical and biological factors influencing the spatial distribution of age-0 walleye wollock (Theragra chalcogramma) around the Pribilof Islands, Bering Sea. Deep Sea Research II 49: 6109-6126

44) Ciannelli, L. (2002) Effects of spatial variability, associated with a frontal structure, on predictions of age-0 walleye pollock (Theragra chalcogramma) growth around the Pribilof Islands, Bering Sea. Estuarine Coastal and Shelf Sciences 55: 151-165

45) Duffy-Anderson, J.T., Bailey, K.M., and L. Ciannelli. (2002) Consequences of a superabundance of larval walleye pollock, Theragra chalcogramma, in the Gulf of Alaska in 1981. Marine Ecology Progress Series 243: 179-190

46) Swartzman G.L., Napp, J., Brodeur, R., Winter A., and Ciannelli, L.. (2002) Spatial patterns of pollock and zooplankton distribution in the Pribilof Islands, Alaska nursery area and their relationship to pollock recruitment. ICES Journal of Marine Sciences 59: 1167-1186

47) Brodeur R.D., Wilson M.T., Ciannelli L., Doyle M., and J.M. Napp.  (2002) Interannual and regional variability in distribution and ecology of juvenile pollock and their prey in frontal systems of the Bering Sea. Deep Sea Research II 49:6051-6067

48) Brodeur, R.D., Wilson, M.T., and L. Ciannelli.  (2000). Spatial and temporal variability in feeding and condition of age-0 walleye pollock in frontal regions of the Bering Sea. 1997.  ICESJournal of Marine Science. 57: 256-264

49) Schabetsberger, R., Brodeur, R.D., Ciannelli, L., Napp, J.M., and G.L. Swartzman. (2000) Diel vertical migration and interaction of zooplankton and juvenile walleye pollock (Theragra chalcogramma) at a frontal region near Pribilof Islands, Bering Sea. ICES Journal of Marine Science 57:1283-1295

50) Ciannelli, L., Brodeur, R.D. and T.W., Buckley. (1998)  Development and application of a bioenergetics model for juvenile walleye pollock.  Journal of Fish Biology. 52: 879-898

51) Ciannelli, L. (1997) Winter dormancy in the pacific sand lance Ammodytes hexapterus in relation to gut evacuation time. Proceedings of Forage Fishes in Marine Ecosystem.  Alaska Sea Grant College Program, AK-SG-97-01: 95-104

52) Ciannelli, L., and R.D. Brodeur. (1997) Bioenergetics estimation of juvenile pollock food consumption in the Gulf of Alaska. Proceedings of Forage Fishes in Marine Ecosystem.  Alaska Sea Grant College Program, AK-SG-97-01: 71-75

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