Distribution patterns of marine cave fishes and the potential role of the cardinal fish Apogon imberbis (Linnaeus, 1758) for cave ecosystem functioning in the western Mediterranean

Fish assemblages associated with 16 marine caves were investigated along the coasts of Spain, France and Italy. Sampling was done in caves that encompassed blind caves (one entrance) and caves with several openings, remarkably variable in morphology, overall extension, presence/absence of ceiling, and characteristics of the bottom. On the whole, 33 fish species were recorded. The distribution patterns of fish assemblages (both in terms of density and biomass) showed a significant variability at the regional (hundreds of kms) and local scale (kms/hundreds of meters), which confirms the great heterogeneity of the cave-associated communities. In terms of occurrence, only the cardinal fish Apogon imberbis and the gobid Corcyrogobius liechtensteini were found in all 16 caves, followed by Scorpaena notata and Serranus cabrilla (n  = 15) and Diplodus vulgaris and Didogobius splechtnai (n  = 11). A significant number of species were occasionally found, like Sarpa salpa and Diplodus annularis . They usually occur outside caves and could be considered as “sporadic cave visitors”. The high densities of A. imberbis and its frequency of occurrence shows that this species is by far the most represented fish within caves in the western Mediterranean. In spite of the conspicuous variation from cave to cave (from 10 to 70% of the whole fish biomass), a general pattern emerges showing that A. imberbis accounts for a significant proportion of the fish biomass. Average density and biomass of A. imberbis are significantly variable at regional scale (hundreds of kms), but not at local scale (kms/hundred meters). A similar pattern could be explained by multiple processes acting concurrently. Although further studies are needed (e.g. to prove nychthemeral movements inside–outside caves for feeding), this study shows that, based on its density and biomass, A. imberbis  has the potential to fulfill a crucial trophic role within Mediterranean marine caves as a vector of organic matter.

[1]  M. Ferrari,et al.  Impact of a harbour construction on the benthic community of two shallow marine caves. , 2017, Marine pollution bulletin.

[2]  P. Chevaldonné,et al.  An ecosystem-based approach to evaluate the ecological quality of Mediterranean undersea caves , 2015 .

[3]  A. Di Franco,et al.  Fish Assemblages of Mediterranean Marine Caves , 2015, PloS one.

[4]  P. Chevaldonné,et al.  Local scale connectivity in the cave-dwelling brooding fish Apogon imberbis , 2015 .

[5]  K. Selkoe,et al.  Phylogeography of the California sheephead, Semicossyphus pulcher: the role of deep reefs as stepping stones and pathways to antitropicality , 2013, Ecology and evolution.

[6]  Hugh P. Possingham,et al.  Ecoregion-Based Conservation Planning in the Mediterranean: Dealing with Large-Scale Heterogeneity , 2013, PloS one.

[7]  J. García-Gómez,et al.  Soft-bottom diversity patterns in marine caves; Lessons from crustacean community , 2013 .

[8]  E. Voultsiadou,et al.  Marine Caves of the Mediterranean Sea: A Sponge Biodiversity Reservoir within a Biodiversity Hotspot , 2012, PloS one.

[9]  S. Fraschetti,et al.  Increasing heterogeneity of sensitive assemblages as a consequence of human impact in submarine caves , 2012 .

[10]  P. Richard,et al.  Feeding strategies and resource partitioning mitigate the effects of oligotrophy for marine cave mysids , 2011 .

[11]  G. Jones,et al.  Synergistic effects of habitat preference and gregarious behaviour on habitat use in coral reef cardinalfish , 2010, Coral Reefs.

[12]  V. Parravicini,et al.  Consequences of sea water temperature anomalies on a Mediterranean submarine cave ecosystem , 2010 .

[13]  M. Milazzo,et al.  Scuba diver behaviour and its effects on the biota of a Mediterranean marine protected area , 2009, Environmental Conservation.

[14]  P. Guidetti,et al.  Do Mediterranean fish assemblages associated with marine caves and rocky cliffs differ , 2009 .

[15]  Raymond N. Gorley,et al.  PERMANOVA+ for PRIMER. Guide to software and statistical methods , 2008 .

[16]  MARTI J. ANDERSONa,et al.  PERMUTATION TESTS FOR MULTIFACTORIAL ANALYSIS OF VARIANCE , 2008 .

[17]  Marti J. Anderson,et al.  Scales of spatial variation in Mediterranean subtidal sessile assemblages at different depths , 2007 .

[18]  S. Fraschetti,et al.  Spatial and temporal variability of sessile benthos in shallow Mediterranean marine caves , 2006 .

[19]  F. Leasi,et al.  Meiofauna densities and gastrotrich community composition in a Mediterranean sea cave , 2006 .

[20]  K. Døving,et al.  Site fidelity and homing in tropical coral reef cardinalfish: are they using olfactory cues? , 2006, Chemical senses.

[21]  R. Patzner.  Habitat Utilization and Depth Distribution of Small Cryptobenthic Fishes (Blenniidae, Gobiesocidae, Gobiidae, Tripterygiidae) in Ibiza (Western Mediterranean Sea) , 1999, Environmental Biology of Fishes.

[22]  P. Guidetti,et al.  Distribution patterns of the cardinal fish, Apogon imberbis, in shallow marine caves in southern Apulia (SE Italy) , 2003 .

[23]  Marti J. Anderson,et al.  Permutation tests for multi-factorial analysis of variance , 2003 .

[24]  P. Guidetti,et al.  Fish Assemblages in Shallow Marine Caves of the Salento Peninsula (Southern Apulia, SE Italy) , 2002 .

[25]  Marti J. Anderson,et al.  Permutation tests for univariate or multivariate analysis of variance and regression , 2001 .

[26]  M. Marnane.  Site fidelity and homing behaviour in coral reef cardinalfishes , 2000 .

[27]  H. Hilgers,et al.  Habitat Selection and Ecology of Two Speleophilic Gobiid Fishes(Pisces: Gobiidae) from the Western Mediterranean Sea , 1999 .

[28]  M. Kovačić.  Gammogobius steinitzi Bath, 1971, a fish new to the Adriatic Sea , 1999 .

[29]  R. Coma,et al.  Horizontal transfer of matter by a cave-dwelling mysid , 1997 .

[30]  K. R. Clarke,et al.  Non‐parametric multivariate analyses of changes in community structure , 1993 .

[31]  F. Boero,et al.  The suspension-feeder communities of a Mediterranean sea cave , 1989 .

[32]  J. Vacelet,et al.  Les grottes sous-marines obscures: un milieu extrême et un remarquable biotope refuge , 1985 .

[33]  R. Pronzato,et al.  DISTRIBUTION OF BENTHIC PHYTO- AND ZOOCOENOSES ALONG A LIGHT GRADIENT IN A SUPERFICIAL MARINE CAVE , 1977 .

[34]  B. E. Livingston.  Research Methods in Ecology , 1924 .

[35]  F. Clements.  Research methods in ecology , 1905 .