Environmental Biology of Fishes

, Volume 101, Issue 1, pp 95–108 | Cite as

Distribution and habitat associations of the California moray (Gymnothorax mordax) within Two Harbors, Santa Catalina Island, California

  • B. A. Higgins
  • R. S. Mehta


While kelp forests are some of the best-surveyed ecosystems in California, information on cryptic inhabitants and their role within the community are lacking. Kelp itself provides overall structure to the habitat; however the rocky reef to which the kelp attaches is known to provide additional structure for cryptic species. Gymnothorax mordax, the California moray, is an elusive predatory species that is considered abundant in the waters around Catalina Island. However, no life history data exists for this species. We examined habitat composition, relative abundance, size pattern distributions, and biomass of G. mordax within Two Harbors, Catalina Island. Habitats were sampled using a combination of baited trap collection and transect surveys using SCUBA. A total of 462 G. mordax were captured, primarily in shallow (< 10 m) waters. Individuals of G. mordax were associated with mostly boulder and cobble substrates. Measurements of relative abundance and density indicate that G. mordax is more prevalent than reported in previous studies. We also discovered that the 6 trapping sites from which all morays were collected, differed in size structuring and density while the relatively high biomass did not change across sites. In general, southern facing sites exhibited higher densities of morays, while northern facing sites showed more size structuring. We show how the structural complexity of the rocky reef habitat in an already diverse kelp forest ecosystem, can support a high biomass of a cryptic elongate predatory fish.


Catalina Island CPUE Muraenidae Habitat Gymnothorax 



The authors are grateful to the Hellman Foundation and Packard grants to R.S.M., the University of California, Santa Cruz Committee on Research grant, and donations via for supporting the research. B.A.H. was in part funded by a UCSC SCWIBLES GK-12 Fellowship from the National Science Foundation (NSF GK-12 DGE-0947923). T. Williams, M. Carr, J. Estes, V. Baliga, C. Law, K. Dale, S. Kienle, C. Jaquemetton, and K. Voss provided valuable input and comments on the manuscript; Sean Hayes, Cyril Mitchell, Rachel Higgins, and Ann Marie Osterback provided invaluable field support; A. Diluzio, S. Eckley, S. Burns, J. Harrison, R. Higgins and J. Redwine assisted with SCUBA transects and data collection; We thank S. Connor, L. Oudin, T. Oudin, K. Spafford, K. Erickson and the staff at the University of Southern California Wrigley Institute for Environmental Studies for equipment and logistical support. All procedures were approved by the Institute of Animal Care and Use Committee (IACUC) at the University of California, Santa Cruz, USA (#1007).

Supplementary material

10641_2017_684_MOESM1_ESM.tif (9.8 mb)
Table S1 Complete loadings list of 5 variables used in PCA analyses. (TIFF 10066 kb)


  1. Allen LG, Bouvier LS, Jenson RE (1992) Abundance, diversity, and seasonality of cryptic fishes and their contribution to a temperate reef assemblage off Santa Catalina Island, California. Bull South Calif Acad Sci 91:55–69Google Scholar
  2. Allen, LG, Pondella II, DJ, Horn, MH (2006) The ecology of marine fishes: california and adjacent waters.  University of California Press, Los AngelesGoogle Scholar
  3. Almany GR (2004) Does increased habitat complexity reduce predation and competition in coral reef fish assemblages? Oikos 106:275–284CrossRefGoogle Scholar
  4. Anderson MJ (2008) Animal-sediment relationships re-visited: characterizing species’ distributions along an environmental gradient using canonical analysis and quantile regression splines. J Exp Mar Bio Eco 366:16–27CrossRefGoogle Scholar
  5. Anderson TL, Semlitsch RD (2016) Top predators and habitat complexity alter an intraguild predation module in pond communities. J Anim Ecol 85:548–558CrossRefPubMedGoogle Scholar
  6. Beck MW (2000) Separating the elements of habitat structure: independent effects of habitat complexity and structural components on rocky intertidal gastropods. J Exp Mar Biol Ecol 249:29–49CrossRefPubMedGoogle Scholar
  7. Böhlke EB, CcCosker JE, Böhlke JE (1989) Family Muraenidae In: Böhlke EB (ed) Fishes of the western North Atlantic. Sears Foundation for Marine Research, Memior No. 1, Part 9, Vol 1, Anguilliformes and Saccopharyngiformes: xvii + pp 655Google Scholar
  8. Carr M, Hixon M (1995) Predation effects on early post-settlement survivorship of coral-reef fishes. Mar Eco Prog Ser 124:31–42CrossRefGoogle Scholar
  9. Christie H, Jrgensen NM, Norderhaug KM, Waage-Nielsen E (2003) Species distribution and habitat exploitation of fauna associated with kelp (Laminaria Hyperborea) along the Norwegian coast. J Mar Biol Assoc UK 83:687–699CrossRefGoogle Scholar
  10. Coull BC, Wells JBJ (1983) Refuges from fish predation: experiments with phytal meiofauna from the New Zealand rocky intertidal. Ecology 64:1599–1609CrossRefGoogle Scholar
  11. Cowen RK (1985) Large scale pattern of recruitment by the labrid, Semicossphyus pulcher: causes and implications. Mar Res 43:719–742CrossRefGoogle Scholar
  12. Crowder LB, Cooper WE (1982) Habitat structural complexity and the interaction between bluegills and their prey. Ecology 63:1802–1813CrossRefGoogle Scholar
  13. Davis, GE, Richards, DV, Kushner, DJ (1996) kelp forest monitoring design review. Technical report CHIS-96-01. Ventura: Channel Islands National ParkGoogle Scholar
  14. Dayton PK, Tegner MJ, Edwards PB, Riser KL (1998) Sliding baselines, ghosts, and reduced expectations in kelp forest communities. Ecol Appl 8:309–322CrossRefGoogle Scholar
  15. Diehl S (1988) Foraging efficiency of three freshwater fishes: effects of structural complexity and light. Oikos 53:207–214CrossRefGoogle Scholar
  16. Diluzio AR, Baliga VB, Higgins BA, Mehta RS (2016) Effects of prey characteristics on the feeding behaviors of an apex marine predator, the California moray (Gymnothorax mordax). Zoology 122: 80–89Google Scholar
  17. Ebeling A, Bray RN (1976) Day versus night activity of reef fishes in a kelp forest off Santa Barbara, California. Fish Bull US 74:703–717Google Scholar
  18. Emson RH, Faller-Fritsch RJ (1976) An experimental investigation into the effect of crevice availability on abundance and size-structure in a population of Littorina Rudis (Maton): Gastropoda: Prosobranchia. Exper Mar Biol Ecol 23:285–297CrossRefGoogle Scholar
  19. Erlandson JM (2001) Anatomically modern humans, maritime voyaging, and the Pleistocene colonization of the Americas. In: Jablonski NG (ed) The first Americans: the Pleistocene colonization of the new world. San Francisco, California Academy of Sciences, pp 1–9Google Scholar
  20. Eschmeyer WN, Herald ES, Hammann H (1983) A field guide to Pacific coast fishes of North America. Houghton Mifflin Company, Boston, p 336Google Scholar
  21. Fishelson L (1997) Olfaction and visual detection of food and relevant morphometric characters in some species of moray eels (Muraenidae). Isr J Zool 43:367–375Google Scholar
  22. Fitch JE, Lavenberg RJ (1971) Marine food and game fishes of California. Canifornia natural history guies: 28, pp. 100-102. University of California Press, Berkeley, California, USAGoogle Scholar
  23. Friedlander AM, Brown EK, Jokiel PL, Smith WR, Rodgers KS (2003) Effects of habitat, wave exposure, and marine protected area status on coral reef fish assemblages in the Hawaiian archipelago. Coral Reefs 22(3):291-305Google Scholar
  24. Froeschke JT, Allen LG, Pondella II DJ (2006) The fish assemblages inside and outside of a temperate marine reserve in Southern California. Bull South Calif Acad Sci 105(3):128–142Google Scholar
  25. Froese R (2006) Cube law, condition factor and weight-length relationships: history, meta-analysis and recommendations. Appl Ichthyol 22:241–253CrossRefGoogle Scholar
  26. Gilbert M, Rasmussen JB, Kramer DL (2005) Estimating the density and biomass of moray eels (Muraenidae) using a modified visual census method for hole-dwelling reef fauna. Environ Biol of Fish 73:415–426CrossRefGoogle Scholar
  27. Grabowski JH (2004) Habitat complexity disrupts predator-prey interactions, but not the trophic cascade on oyster reefs. Ecology 85:995–1004CrossRefGoogle Scholar
  28. Graham MH (2004) Effects of local deforestation on the diversity and structure of Southern California Giant kelp Forest food webs. Ecosystems 7:341–357CrossRefGoogle Scholar
  29. Graham NAJ, Nash KL (2013) The importance of structural complexity in coral reef ecosystems. Coral Reefs 32:315–326CrossRefGoogle Scholar
  30. Gray JS (1974) Animal-sediment relationships. Oceanogr Mar Biol Ann Rev 12:223–261Google Scholar
  31. Harrison JS, Higgins BA, Mehta RS (2017) Scaling of dentition and prey size in the California moray (Gymnothorax mordax). J Zool 122:16–26CrossRefGoogle Scholar
  32. Harvey E, Fletcher D, Shortis M, Kendrick G (2004) A comparison of underwater visual distance estimates made by scuba divers and a stereo-video system: implications for underwater visual census of reef fish abundance. Mar Freshw Res 55:573–580CrossRefGoogle Scholar
  33. Helfman GS (1986) Fish behaviour by day, night and twilight. In: Pitcher TJ (ed) The behaviour of teleost fishes. Johns Hopkins University Press, Baltimore, pp 366–387CrossRefGoogle Scholar
  34. Hereu B, Zabala M, Linares C, Sala E (2005) The effects of predator abundance and habitat structural complexity on survival of juvenile sea urchins. Mar Biol 146:293–299CrossRefGoogle Scholar
  35. Higgins BA, Pearson D, Mehta RS (2017) El Niño episodes coincide with California moray Gymnothorax mordax settlement around Santa Catalina Island. California Fish Biol Early.
  36. Hixon MA, Beets JP (1989) Shelter characteristics and Caribbean fish assemblages: experiments with artificial reefs. Bull Mar Sci 44:666–680Google Scholar
  37. Hixon MA, Beets JP (1993) Predation, prey refuges, and the structure of coral reef fish assemblages. Ecol Monogr 63:77–101CrossRefGoogle Scholar
  38. Hobson ES, Chess JR (1986) Relationships among fishes and their prey in a nearshore sand community off southern California. Environ Biol Fish 17:201–226CrossRefGoogle Scholar
  39. Hood PB, Able KW, Grimes CB (1988) Biology of the conger Conger oceanicus in the mid-Atlantic bight. Mar Biol 98:587–596CrossRefGoogle Scholar
  40. Hu H, Liu T (2002) QuickSCAT reveals the surface circulation of the Catalina Eddy. Geophys Res Let 29:2–1–2-4Google Scholar
  41. Huston MA, DeAngelis DL (1994) Competition and coexistence: the effects of resource transport and supply rates. Am Nat 144:954–977CrossRefGoogle Scholar
  42. Jenkins GP, May HMA, Wheatley MJ, Holloway MG (1997) Comparison of fish assemblages associated with seagrass and adjacent unvegetated habitats of port Phillip Bay and corner inlet, Victoria, Australia, with emphasis on commercial species. Estuar Coast Shelf Sci 44:569–588CrossRefGoogle Scholar
  43. Levins R (1979) Coexistence in a variable environment. Am Nat 114:765–783CrossRefGoogle Scholar
  44. Li Y, Brose U, Meyer K, Rall BC (2016) How patch size and refuge availibility change interaction strength and population dysnamics: a combined indivual- and population based modeling experiment. Peer J Preprints 4:e2190v2Google Scholar
  45. Lin Y, Hsuing J, Piersall R, White C, Lowe CG, Clark CM (2016) A multi-autonomous underwater vehicle system for autonomous tracking of marine life. Journal of Field Robotics 34(4):757–774CrossRefGoogle Scholar
  46. Lozano-Álvarez E, Briones-Fourzán P, Álvarez-Filip L, Weiss HM, Negrete-Soto F, Barradas-Ortiz C (2010) Influence of shelter availability on interactions between Caribbean spiny lobsters and moray eels: implications for artificial lobster enhancement. Mar Ecol Prog Ser 400:175–185CrossRefGoogle Scholar
  47. Maechler M (2016) diptest - Hartigan’s dip test statistic for unimodality – corrected. R package version 0.75-7Google Scholar
  48. Mann KH (1973) Seaweeds: their productivity and strategy for growth. Science 118:975–981CrossRefGoogle Scholar
  49. Matić-Skoko S, Tutman P, Petrić M, Skaramuca D, Dikić D, Lisičić D, Skaramuca B (2011) Mediterranean moray eel Muraena Helena (Pisces: Muraenidae): biological indices for life history. Aqua Biol 13:275–284CrossRefGoogle Scholar
  50. McCleneghan K (1973) The ecology and behavior of the California moray eel, Gymnothorax mordax (Ayres, 1859) with descriptions of its larva and the leptocephali of some other east pacific muraenidae. Ph.D. dissertation. University of Southern CaliforniaGoogle Scholar
  51. Nash KL, Graham SK, Wilson SK, Bellwood DR (2013) Cross-scale habitat structure drives fish body size distributions on coral reefs. Ecosystems 16:478–490CrossRefGoogle Scholar
  52. O’Sullivan SO, Moriarty C, FitzGerald RD, Davenport J, Mulcahy MF (2003) Age, growhn and reproductive status of the European conger eel, Conger conger (L.) in Irish coastal waters. Fish. Res 64:55–69Google Scholar
  53. Oksanen J, Guilluame Blanchet F, Friendly M, Kindt R, Legendre P et al (2017) vegan: Community ecology package. R package version 2.4-4Google Scholar
  54. Page H, Brooks A, Kulbicki M, Galzin R (2013) Stable isotopes reveal trophic relationships and diet of consumers in temperate kelp Forest and coral reef ecosystems. Oceanography 26:180–189CrossRefGoogle Scholar
  55. Parrish JD, Norris JE, Callahan MW, Callahan JK, MagarifujiI EJ, Schroeder RE (1986) Piscivory in a coral reef fish community. Environ Biol Fish 14:285–297Google Scholar
  56. Pohlert T (2016) PMCMR: Calculate pairwise multiple comparisons of mean rank sums. R package version 4.1Google Scholar
  57. Robinson KM (2015) Motile cryptofaunal invertevrate assemplages in Catalina Island’s rhodolith beds in relation to physical structure and live rhodoliths. California State University, Monterey Bay, MS thesisGoogle Scholar
  58. Safriel UN, Ben-Eliahu MN (1991) The influence of habitat structure and environmental stability on the species diversity of polychates in vermetid reefs. In: Bell SS, McCoy ED, Mushinsky HR (eds) Habitat structure: the physical arrangement of objects in space. Chapman and Hall, New York, pp 349–369CrossRefGoogle Scholar
  59. Sánchez-Caballero CA, Borges-Souza JM, De La Cruz-Agüero G, Ferse SCA (2017) Links between fish community structure and habitat complexity of a rocky reef in the Gulf of California threatened by development: Implications for mitigation measures. Ocean & Coastal Management 137:96-106Google Scholar
  60. Sandoval EJ (2005) Topographic complexity and benthic community variability within a kelp forest in Monterey Bay, CA. California State University, Monterey Bay, MS thesisGoogle Scholar
  61. Simenstad CA, Estes JA, Kenyon KW (1978) Aleuts, sea otters, and alternate stable state communities. Science 200:403–411CrossRefPubMedGoogle Scholar
  62. Smith DG (2012) A checklist of the moray eels of the world (Teleostei: Anguilliformes: Muraenidae). Zootaxa 3474:1–64Google Scholar
  63. Smith, RS, Johnston, EL, Clark, GF, (2014) The role of habitat complexity in community development is mediated by resource availability PLoS ONE e102920Google Scholar
  64. Steneck RS, Graham MH, Bourque BJ, Corbett D, Erlandson JM, Estes JA, Tegner MJ (2002) Kelp forest ecosystems: biodiversity, stability, resilience and future. Environ Conserv 29:436–459CrossRefGoogle Scholar
  65. Stephens JS, Larson RJ, Pondella DJ II (2006) Chapter 9: Rocky reefs and kelp beds. In: Allen LG, Pondella DJ II, Horn M (eds) The ecology of marine fishes: California and adjacent waters. University of California Press, Los AngelesGoogle Scholar
  66. Thrush SF, Hewitt JE, Norkko A, Nicholls PE, Funnel GA, Ellis JI (2003) Habitat change in estuaries: predicting broad-scale responses of intertidal macrofauna to sediment mud content. Mar Ecol Prog Ser 263:101–112CrossRefGoogle Scholar
  67. Willis TJ, Anderson MJ (2003) Structure of crypitc reef fish assemblages: relationships with habitat characteristics and predator density. Mar Ecol Prog Ser 257:209-221Google Scholar
  68. Young R, Winn H (2003) Activity patterns, diet, and shelter site use for two species of moray eels, Gymnothorax Moringa and Gymnothorax Vicinus, in Belize. Copeia 2003:44–55Google Scholar

Copyright information

© Springer Science+Business Media B.V. 2017

Authors and Affiliations

  1. 1.Department of Ecology and Evolutionary Biology, Coastal Biology BuildingUniversity of California Santa CruzSanta CruzUSA

Personalised recommendations