Otolith Assemblage Research Articles

Late Miocene fish otoliths from the Colombacci Formation (Northern Apennines, Italy): implications for the Messinian ‘Lago-mare’ event

A fish otolith assemblage from the Messinian ‘Lago-mare’ deposits of the Colombacci Formation cropping out in the Montecalvo in Foglia Syncline, Marche, central Italy, is described. The assemblage displays a low diversity and consists of seven taxa belonging to three families: the Gobiidae, Myctophidae and Sciaenidae. Sciaenid otoliths are the most abundant elements representing 88% of the entire assemblage. The palaeoecological analysis reveals a coastal shallow marine environment strongly influenced by continental outflow. The low diversity and high abundance of the euryecious sciaenids are indicative of a very simplified food web, which probably represented an ecological response to the fluctuating environmental parameters and available food resources. The fish remains documented here provide an unambiguous evidence that normal marine conditions were present in the Mediterranean, at least in the upper part of the ‘Lago-mare’ event, and unquestionably demonstrate that the marine refilling preceded the Mio-Pliocene boundary. These findings clearly demonstrate that fishes, because of their mobility and migratory behaviour, represent a useful tool for the large-scale interpretation of the environmental conditions of the Messinian Mediterranean water body. The necessity of a new scenario of palaeoenvironmental evolution for the post-evaporitic Messinian of the Mediterranean is also discussed. Copyright © 2006 John Wiley & Sons, Ltd.

Seasonality only works in certain parts of the year: the reconstruction of fishing seasons through otolith analysis

AbstractSeasonality estimations using incremental data usually suffer from small sample sizes and from the lack of comparison with sufficiently large modern samples. The present contribution reports on incremental studies carried out on large assemblages of plaice (Pleuronectes platessa) and haddock (Melanogrammus aeglefinus) from a late medieval fishing village (Raversijde, Belgium) on the North Sea coast. In an attempt to refine previous seasonality estimates made for this site, and to expand conclusions concerning general methodology, extensive monthly samples of modern otoliths of these species, caught within the North Sea, have also been investigated. The modern material shows that the timing of the seasonal changes in the edge type (hyaline or opaque) of the otoliths is extremely variable and that it is dependent on the fishing ground, the year considered, and the age of the fish. It also appears that the increase of the marginal increment thickness is highly variable, to such an extent that the thickness of the last increment of a single otolith is mostly useless for seasonality estimation. Where large archaeological otolith assemblages can be studied, preferably from single depositional events, seasonality determination becomes possible on the condition, however, that the archaeological assemblage corresponds to fish that were captured during their period of fast growth. The growth ring study on the otoliths from Raversijde shows that plaice fishing took place in spring and that it was preceded by a haddock fishing season, probably in late winter/early spring. Copyright © 2004 John Wiley & Sons, Ltd.

Distribution of otoliths in surficial sediments of the U.S. Atlantic Continental Shelf and slope and potential for reconstructing Holocene fish stocks

We examined more than 1100 surface sediment samples from the Atlantic continental margin of the United States to determine the feasibility of using fossil fish otoliths as diagnostic tools in reconstructing paleoenvironments and latitudinal distribution of fish stocks during the Holocene. Although 63% of the 1107 samples collected were from shelf areas (<140 m), the total number of shelf‐derived otoliths represents only 0.3% of the entire sampled assemblage. The majority of otoliths occurred on the continental slope (400‐2000 m), with a maximum concentration in sediments at 500 to 600‐m water depth. Otoliths of the most commonly occurring species, Ceratoscopelus maderensis, exhibit a marked distributional boundary just south of Cape Hatteras, North Carolina (33°N), which mimics the distribution of their living counterparts. North of this boundary, C. maderensis constitutes greater than 70% of the preserved otolith assemblage, whereas more southerly regions contain no otoliths of this species. Although C. maderensis typically migrates diurnally over a depth of 300‐600 m, otoliths taken from live‐captured C. maderensis exhibit Δ14C values comparable to that of the dissolved inorganic carbon (DIC) of surface seawater in the study area. Accelerator mass spectrometry radiocarbon analyses of cooccurring otoliths and planktonic foraminifera from a sediment core collected south of Martha’s Vineyard (40°15′N 70°51′W, 265 m) demonstrate temporal concordance throughout the Holocene. Otoliths appear to be viable, underutilized paleoceanographic tools. Specimens are found in sufficient abundance to permit temporal reconstructions of the distribution of C. maderensis and potentially several other icthyospecies along the U.S. Atlantic continental margin.

Paleontologic and biostratigraphic observations on the Pliocene of Camarones (Esmeraldas, Ecuador)

Studies on the Onzole Formation outcropping close to the Camarones village (Esmeraldas Province, Northwestern Ecuador) have been carried out. Analyses on foraminifer, otolith and mollusc assemblages have shown an age referable to the Early Pliocene and a bathyal environment. These communities correspond to those of the modern Tropical East Pacific Province. However in the ichthyofauna some taxa, today related to the cool California Current, occur.

A marine ichthyofauna from the Miocene of Panama, and the Tertiary Caribbean faunal province

ABSTRACT The marine vertebrate fauna collected from the Gatun Formation, middle Miocene of Panama, includes the following genera in the non-otolith assemblage: Carcharodon, Procarcharodon, Ginglymostoma, Hemipristis, Galeocerdo cf. Carcharhinus, Sphyrna cf. Isistius, Dasyatis, Myliobatis, Rhinoptera, Aetobatus, Acipenser, Sphyraena, Trichiurus, Lepisosteus and unidentified crocodilian, chelonian, and mammalian taxa. The otolith assemblage consists of 20 taxa of bony fishes. The fauna contains a mixture of marine forms representing coastal to open-water habitats. The Gatun ichthyofauna compares favorably to the Miocene selachian fauna from Ecuador, the Miocene ichthyofaunas from the Caribbean, and the large ichthyofauna from the Pungo River Formation in North Carolina, U.S.A. These tropical occurrences collectively represent the vertebrate fauna of the Tertiary Caribbean Faunal Province that reached its greatest interoceanic connection between the Pacific and the Caribbean in the Miocene. The provincial li...

Paleobathymetry by Fish Otoliths: ABSTRACT

Four distinct faunal zones are present in otolith assemblages of bottom muds from the eastern Gulf of Mexico, between depths of 300 and 2,000 ft. At least 2 more zones can be projected on the basis of the literature and known water-circulation patterns in the Gulf, and the outer limit of workable faunas may be far out on the abyssal plain. Within the documented depth range, surprising precision is obtained by measuring End_Page 775------------------------------ the ratio of known forms which inhabit different sonic scattering layers in mid-water. The lowermost layer represented in each fauna is in part a function of water depth, and also commonly indicates the boundary between water masses of sedimentologic importance. The 4 zones detailed in this study are (1) mid-shelf; (2) cold bottom and epipelagic, or shelf-edge; (3) lanternfish, or oxygen minimum; and (4) bathypelagic, or Antarctic water. All these zones may be subdivided by later investigations. End_of_Article - Last_Page 776------------