The Late Cretaceous was a time of blossoming teleost diversification that came to a sudden restriction and partial termination during the extinction event at the Cretaceous–Paleogene (K/Pg) boundary. Among the dominant and diverse Late Cretaceous teleost groups prior to the K/Pg boundary event were certain pelagic Aulopiformes (e.g., Ichthyotringoidei and Enchodontoidei) and a large variety of basal Acanthomorpha whose relationships are difficult to determine. The skeletal record diminishes during the late Campanian and is low in the Maastrichtian and Paleocene, constituting the so-called ‘Patterson’s Gap’. Recent studies of fossil otoliths, however, have significantly increased the number of taxa recognised for this time inerval, but most of the putative extinct forms lack adequate calibration with otoliths found in situ in articulated skeletons. However, the otolith assemblages do confirm the presence of great morphological diversity among Aulopiformes and Acanthomorpha incertae sedis that became extinct at the K/Pg boundary. In the present review, we elucidate the effect of the K/Pg boundary from an otolith perspective and categorise extinct lineages and survivors. It is interesting to recognise that several of the surviving lineages are represented by groups that probably originated during the Late Cretaceous but were not particularly common up to the K/Pg boundary and began to expand rapidly and diversify during the early Paleogene. Such lineages probably took advantage to populate void ecospace that may have opened following the extirpation of previously dominant lineages. During the early Paleogene, the otolith record shows that the Ophidiiformes and perciforms s. lat. were the ones that diversified the most rapidly and became the most abundant, and in certain areas associated with the Gadiformes.

Age and growth of the yellowmouth barracuda Sphyraena viridensis (Cuvier, 1829) was examined in 698 individuals (184 < TL (mm) < 1210; 25 < TW (g) < 7125), sampled monthly from commercial catches in eastern coasts of Algeria between January 2007 and January 2008. Marginal increment analysis of 159 sectioned sagittal otoliths combined with information derived from length–frequency distribution showed that annulus formation occurs between June and August. Maximum observed age of males and females is 14 and 13 years respectively. Back calculations of total length-at-age were used to fit the data to the Bertalanffy growth model: TL = 1113(1 – e−0.165(t+2.251)) in males and TL = 958.3 (1 – e−0.247(t+1.422)) in females. The coefficient of allometry of the length weight relationship is 3.02 and 2.99 in males and females, respectively. Growth performance index Ø = 3.33. Natural mortality (M) was estimated as 0.45 year−1, fishing mortality (F) was 0.06 year−1and the exploitation rate (E) was 0.11.

The Willandra Lakes region is a series of once interconnected and now-dry lake basins in the arid zone of southeastern Australia. It is a UNESCO World Heritage Site of cultural, archaeological, and geological significance, preserving records of Aboriginal occupation and environmental change stretching back to at least 50 ka. Linking the archaeology with the commensurate palaeoenvironmental information is complicated by the millennial time spans represented by the past hydrological record preserved in the sediment vs. the subdecadal evidence of each archaeological site. Oxygen isotope records across annual growth rings of fish otoliths (ear stones) can elucidate flooding and drying regimes on subannual scales. Otoliths from hearth sites (fireplaces) link lake hydrology with people eating fish on the lakeshore. Oxygen isotopic trends in hearth otoliths from the last glacial maximum (LGM) were previously interpreted in terms of high evaporation under dry conditions. However, this ignored hydrology-driven changes in water δ18O. Here, a mass balance model is constructed to test the effect lake desiccation has on water δ18O and how this compares with the LGM otolith records. Based on this modelling, we suggest that Lake Mungo otolith signatures are better explained by evaporation acting on full lakes rather than by lake drying.

Age and growth of blue antimora Antimora rostrata were examined for the first time in the waters of Kerguelen and Crozet Islands (southern Indian Ocean, sub-Antarctic). The longline catches were represented by fish ranging from 39 to 72 cm in total length with weights between 400 and 3310 g, aged 16– 41 years. A minimum age of 16 years was observed in a fish 39 cm long, while a maximum age of 41 years was recorded for an individual of 70 cm in length and 3310 g in weight. The age classes with the greatest numbers were represented by fish aged 34 years (9%), 28 years (9%) and 29 years (8%), which together accounted for 26% of the total catch. The blue antimora in the southern Indian Ocean shows similar growth rates to those of individual fish from the Ross, Lazarev and Weddell Seas and southeastern Greenland, which may indicate the population unity of the species within the Antarctic and sub-Antarctic waters or similar habitat conditions in these areas.

For the first time, the results of the study of the age and growth of blue hake Antimora rostrata in the waters of the Lazarev and Weddell seas (Antarctic) are presented. The longline catches were represented by fish from 42 to 69 cm in total length with weights between 420 and 2,900 g, and most individuals aged 25 to 27 years. A minimum age of 16 years was observed in a fish 47 cm long and weighing 450 g, while a maximum age of 35 years was recorded for an individual of 69 cm in length and 1,640 g in weight. The blue hake in the Lazarev and Weddell seas shows similar growth patterns to the fish from the Ross Sea and waters off Greenland.

Although the red striped mullet is one of the main target fish of the Hellenic demersal fisheries, information about its biology is limited. The aim of this study was to describe the reproductive biology and growth of the species in the south Aegean Sea based on 1032 individuals sampled under the Data Collection Framework Program in 2016. According to the monthly variation of the maturity stages and the gonadosomatic index, spawning activity took place from March to July, although it appeared to occur throughout the year. Length at 50% maturity (L50) was 153.3 and 139.2 mm in females and males, respectively. Individual ages were determined by counting the annuli of otoliths macroscopically. Marginal increment analysis (MIA) combined with complementary information derived from otolith edge analysis, the assessment of the reproductive period and the length–frequency distribution modes of the population showed that annulus formation occurs between February and April. The length–weight relationship revealed a significant sex effect and was described by the parameters α = 0.0155 and b = 2.915 in females, and α = 0.0032 and b = 2.976 in males. The von Bertalanffy growth function (VBGF) parameters for sexes combined were Linf = 346.1 mm, k = 0.299 year−1 and t0 = −0.984 years. Longevity (tmax) was estimated at 11.75 years. This study provides valuable data for the stock assessment of M. surmuletus in one of the major Hellenic fishing grounds located in the south Aegean Sea.

This paper highlights new research on the biomineralization of otoliths and uses a mineralogical approach to understand mechanisms of crystal growth and metal incorporation into otoliths. Petrographic observations of the nucleation of otolith growth in the core for several fish species reveals that sagittal otoliths appear to nucleate around a few or many nucleation sites (primordia) and that these sites vary in size (ranging in diameter from 1 to 20 μm), depending on the species. Spectroscopic data show a large Mn-enrichment in the primordia within the core but the reasons for this enrichment are still unclear (e.g. organic matter or possibly another material other than CaCO3). This study also provides the first multi trace-element data for endolymph fluid and the growing otolith; we found large enrichments (Ca and Sr) and depletions (Na, K, Zn and Rb) of elements in the otolith relative to the endolymph. The last part of this paper examines the effect of crystal structure on the microchemistry ofotoliths. Our investigation helps understand how the chemical characteristics of the metal ions (i.e. ionic radii) and the crystalline structure interact to cause differential trace-metal uptake between the CaCO3 polymorphs, aragonite and vaterite.

In the present study a comparison of the otolith morphology of two species of parrotfish, family Scaridae, collected from the Red Sea coast of Egypt, is conducted to identify the most appropriate taxonomic characters that separate these species. Ontogenetic changes in the otoliths of the two scarid fishes become evident. In the otoliths of Chlorurus sordidus, the following characters are comparable in small-sized adult fishes: otolith width, otolith depth, mesial surface shape, lateral surface shape, shape of sulcus acusticus, column, rostrum and size of rostrum. The otoliths of young adults (GI) C. sordidus differ from the adult ones in 14 out of the 22 characteristics studied. In the otoliths of Hipposcarus harid, the following characters are comparable in small and large fish: otolith width, otolith depth, mesial and lateral surface shapes, shape of sulcus acusticus, rostrum and size of rostrum.

This paper provides for the first time data on age and growth of Remora osteochir, also describing its sagittal otolith together with other biological and ecological aspects. Overall, 236 individuals of marlin sucker were collected in the southern-central Mediterranean Sea, from 2008 to 2009. All samples were hosted by the Mediterranean spearfish, Tetrapturus belone, caught by surface longline and harpoon. Analysis of gonads identified a reproductive peak during June and July. The estimated growth parameters according to the von Bertalanffy equation were: L∞ = 27.37 cm TL, k = 0.248 year−1, t0 = −1.36 year. The length-weight relationship, computed by using eviscerate weight, highlighted an isometric growth for both sexes, as supported by the other results: similar sizes, growth curves and disc length-total length relationship.

The grouper Cephalopholis taeniops is a carnivorous fish of the Cape Verde coastal marine ecosystem. Nothing is known regarding the age and growth of this epinephelid. In this study, the age and growth of C. taeniops was investigated by annual growth increment counts from 2804 specimens (7–51 cm total length) collected between January 2005 and December 2011. Whole otoliths underestimated the age indicated in sections by approximately 70%; therefore, sectioned otoliths were used in this study. A year's growth was represented by one opaque and one translucent ring. There was no apparent time lag from the start of the increase in the seawater temperature and the beginning of the formation of the opaque ring. The formation of the translucent rings coincided with a decrease in surface seawater temperature. Cephalopholis taeniops is a slow-growing and long-lived species, with ages of up to 20 years recorded. The seasonalized von Bertalanffy growth function was the best fitted among the four models tested, with an Akaike weight higher than 0.99. Growth was described by the seasonalized von Bertalanffy growth function as follows: L∞ = 54.26 cm, k = 0.135 year−1, t0 = −0.853 year, C = 0.439 and ts = 0.667.

This study is based on the analysis of the stomach content and the morphology and morphometry of the three pairs of otoliths (sagitta, asteriscus and lapillus) of Lepidonotothen larseni (Lönnberg) collected at the South Shetland Islands and Antarctic Peninsula during summer, in order to find possible relationships between ontogenetic change of sagittal otolith shape and feeding ecology. Length-weight relationship resulted in a positive allometric growth, with juveniles and adults in good nutritional condition (Le Cren condition index > 1), and with a decreasing trend from noon to late evening of the stomach repletion index. The stomach content consisted of several prey, with copepods and amphipods more frequent and abundant in juveniles, whereas euphausiids were in adults. The morphometric analysis of otoliths enabled us to relate different measurements with fish size, and those contributing mostly to separate juveniles from adults were the otolith and rostrum length and their percentage (R index). Juveniles proportionally showed a shorter and wider sagitta than adults reflected in a major E index because of a rounded shape and a minor R index because of a less developed rostrum. This pattern can be tentatively linked to the different habitat of juveniles and adults of this species, being respectively pelagic and epibenthic, as also evidenced by the ontogenetic change of feeding habits.

The biocrystallization process and the prescence of manganese in sagitta otoliths is described for the first time via electron paramagnetic spectroscopy. Spectra of Mn2+ are applied to verify inter-species differences in 12 Sciaenidae species and geographic variations among three stocks of banded croaker Paralonchurus brasiliensis and rake stardrum Stellifer rastrifer. Similar spectra shape and zero-field splitting D (22.4 mT) indicated that the biocrystallization process is the same for all fish species, at any stage of development and under different environmental conditions, corresponding to Mn2+ in the aragonite (CaCO3). Inter-species differences in Mn2+ concentration were detected regarding the otolith shape. Elongated otoliths have higher manganese concentrations compared to rounded otoliths. Geographic variations among stocks of P. brasiliensis and S. rastrifer could be detected. Fish stocks under riverine influence have less Mn2+ concentration than ones under marine influence. Manganese detection via electron paramagnetic spectroscopy is a non-destructive approach that can be useful in fish stocks studies.

Morphological differences in the otoliths of Macrodon atricauda from Rio Grande do Sul State (southern Brazil) and of M. ancylodon from Pará State (northern Brazil) were examined. Until recently, these were considered two populations of the same species. Although relatively similar in their general shape, those of large M. atricauda (>300 mm total length) were shorter and thinner and their outer surface was convex (those of the smallest specimens had a more lobullated antero-dorsal margin) whereas those of similarly sized M. ancylodon were larger, thicker and less lobullated. These features of the otoliths allow these morphologically similar species to be discriminated. The pattern of translucent and opaque bands in sectioned otoliths also differed. The otoliths of M. atricauda showed clear annual banding which allowed ageing, while those of M. ancylodon had no distinct alternate bands.

The age and growth of the snowy grouper, Epinephelus niveatus, from central and south-eastern Brazil were studied by otolith analysis from a sample of 341 specimens, ranging from 325 to 1216 mm in total length (TL) caught with bottom longlines between 1996 and 1998. Otolith length grew proportionally with the increasing TL of the fish. Marginal increment analysis indicated that a single opaque band forms each year during autumn–winter. The maximum estimated age was 54 years, which significantly extends the previously estimated life-span of 21–29 years for this species. The von Bertalanffy growth parameters for both sexes were estimated as L∞ = 1098.4 mm TL, K = 0.062 year −1 and t0 = –2.68. The study revealed differences in mean length-at-age and size at recruitment, as well as in growth parameters between the central and the south-eastern Brazilian coast, which can be attributed mainly to different fishing pressures. The snowy grouper was found at depths of 82–492 m, and showed a positive relationship between age and depth, suggesting differential movements of older fish to deeper waters.

The white-beaked dolphin Lagenorhynchus albirostris is the most numerous cetacean after the harbour porpoise Phocoena phocoena in the North Sea, including Dutch coastal waters. In this study, the diet of 45 white-beaked dolphins stranded on the Dutch coast between 1968 and 2005 was determined by analysis of stomach contents. Although 25 fish species were identified, the diet was dominated by Gadidae (98.0% by weight, 40.0% in numbers), found in all stomachs. All other prey species combined contributed little to the diet by weight (2.0%W). The two most important prey species were whiting Merlangius merlangus (91.1% frequency of occurrence (FO), 30.5%N, 37.6%W) and cod Gadus morhua (73.3%FO, 7.4%N, 55.9%W). In numbers, gobies were most common (54.6%N), but contributed little to the diet by weight (0.6%W). Three stomachs contained different prey compared to the others: one animal had taken 2250 gobies, accounting for 96.4% of all gobies found; one animal had fed on 29 small sepiolids; and one animal had solely taken haddock Melanogrammus aeglefinus. Squid and haddock were not found in any other stomach. The overall diet showed a lasting predominance of whiting and cod, without clear changes over time (35 years) or differences between sexes or size-classes of dolphins. This study adds to earlier published and unpublished data for Dutch coastal waters and agrees well with studies of white-beaked dolphins from other parts of the species’ range, in the North Sea and in Canadian waters, with Gadidae dominating the diet on both sides of the Atlantic.

Some biological parameters of Jenyns' sprat Ramnogaster arcuata in Bahía Blanca estuary, Argentina, were evaluated during a survey conducted on a monthly basis between September 2005 and August 2006. Jenyns' sprat specimens were observed in the estuary all through the year. Total length (TL; N = 721) ranged from 33 to 131 mm. No significant differences between the length–weight relationships of males and females were detected (P > 0.10). Positive allometric growth was observed in juveniles, males, females and sexes combined. Whole otolith analysis revealed four age groups (0–3), 1-year age being the most abundant. Gompertz growth parameters were L∞: 102.75 mm, k = 0.46 and t0 = 0.98 for males (r = 0.80), and L∞: 125.45 mm, k = 0.33 and t0 = 0.68 for females (r = 0.76). Males and females reached 50% sexual maturity (TL50) at 76 and 77 mm TL (age 1 year), respectively, and all individuals were sexually mature at a 110 mm-length at the age of 3 years. Macroscopic gonad inspection, gonadosomatic index and the high percentage of fish of the smallest size-class captured during spring and summer samplings indicate that the spawning season began in spring. Taken together, our results indicate that the biology of R. arcuata is fairly consistent with the biology of other temperate clupeoids.