Rattail Fish Research Articles

Morphometric variation of fish scales among some species of rattail fish from New Zealand waters

New Zealand rattail fish are of great interest both to biologists who study their phylogenetics and in fisheries. In contrast, their morphological evolution is little studied and poorly understood. Geometric morphometric methods based on scale shape were applied in this study to determine differences among species and genera. Scale shapes were described using seven landmarks, the coordinates of which were subjected to a generalized Procrustes analysis, followed by a principal components analysis. A cross-validated discriminant analysis was applied to assess and compare the size-shape (centroid size plus shape variables) efficacy in the species and the discrimination of the genera. Two main phenetic groups were identified: cluster no. 1 with eight species and cluster no. 2 with six species. Coelorhinchus aspercephalus and Mesovagus antipodum were more separated from the other species in the first cluster. The cross-validated canonical discriminant analysis correctly classified 74% at the genus level, with most misclassifications occurring between Coelorhinchus and Coryphaenoides, whereas the best classified genera were Mesovagus and Trachyrincus. The discrimination of correctly classified species ranged from 41.2 to 100%. The highest correct classification rates were recorded for Coryphaenoides armatus, Coelorhinchus innotabilis, Trachyrincus longirostris and Mesovagus antipodum.

Environmental and bathymetric influences on abyssal bait-attending communities of the Clarion Clipperton Zone

The Clarion-Clipperton Zone (CCZ) is one of the richest manganese nodule provinces in the world and has recently become a focus area for manganese nodule mining interests. However, this vast area remains poorly studied and highly undersampled. In this study, the abyssal bait-attending fauna is documented for the first time using a series of baited camera deployments in various locations across the CCZ. A bait-attending community intermediate between those typical of the California margin and Hawaii was found in the larger CCZ area, generally dominated by rattail fishes, dendrobranchiate shrimp, and zoarcid and ophidiid fishes. Additionally, the western and eastern ends of the CCZ had different communities, with the western region characterized by decreased dominance of rattails and small shrimps and increased dominance of ophidiids (especially Bassozetus sp. and Barathrites iris) and large shrimps. This trend may be related to increasing distance from the continental margin. We also test the hypothesis that bait-attending communities change across the CCZ in response to key environmental predictors, especially topography and nodule cover. Our analyses showed that higher nodule cover and elevated topography, as quantified using the benthic positioning index (BPI), increase bait-attending community diversity. Elevated topography generally had higher relative abundances, but taxa also showed differing responses to the BPI metric and bottom temperature, causing significant community compositional change over varying topography and temperatures. Larger individuals of the dominant scavenger in the CCZ, Coryphaenoides spp., were correlated with areas of higher nodule cover and with abyssal hills, suggesting these areas may be preferred habitat. Our results suggest that nodule cover is important to all levels of the benthic ecosystem and that nodule mining could have negative impacts on even the top-level predators and scavengers in the CCZ. Additionally, there is continuous change in diversity, dominance, and relative abundance across the CCZ and across gradients in bathymetric and oceanographic variables. This work increased the understanding of the biogeography of the demersal scavengers and top predators as well as the key environmental drivers of their distributions across the CCZ in order to better predict and manage the impacts of nodule mining.

A review of early gadiform evolution and diversification: first record of a rattail fish skull (Gadiformes, Macrouridae) from the Eocene of Antarctica, with otoliths preserved in situ

Codfishes, the Gadiformes, are quite abundant in modern temperate and polar waters with a fossil record ranging back into the Palaeogene. The oldest records are from the Danian and Selandian of Europe and South Australia. The bipolar distribution early in their evolutionary history implies that their origin must have occurred quite early in the Palaeocene, or even in the Late Cretaceous with subsequent rapid diversification. By the Eocene, gadiforms were highly abundant and widespread. With the exception of gadiforms, no Eocene Antarctic teleostean group is present in the modern Antarctic fauna. Here, we review the early evolution and diversification of gadiforms in general and of macrouroids in particular. We also describe the undoubtedly oldest skeletal macrourid specimen with otoliths preserved in situ. It is the first definitive record of this group from the Eocene of Antarctica filling a gap in its stratigraphic distribution. The fossil record of gadiforms in general and macrouroids in particular indicates that the origin of both was in shallow shelf environments but with adaptations to deep-water settings early in their evolution. While gadoids seemingly originated in the earliest Palaeogene and rapidly experienced a first major radiation event in the eastern North Atlantic and/or North Sea Basin, macrouroids evolved in the Southern Ocean and migrated northwards into the South Atlantic before the establishment of the circum-Antarctic current and subsequent isolation of the Antarctic fish fauna. These two timely and regional separated adaptive radiation events in the Palaeogene gave rise to their modern taxonomic diversity and global distribution.

Comparative sequence analysis of myosin heavy chain proteins from congeneric shallow- and deep-living rattail fish (genus Coryphaenoides)

The evolutionary adaptations of functional genes to life at high pressure are not well understood. To elucidate the mechanisms of protein adaptation to high pressure, we cloned the myosin heavy chain (MyHC) cDNA from skeletal muscle of two deep-sea fishes, Coryphaenoides yaquinae and C. armatus, and two non-deep-sea fishes, C. acrolepis and C. cinereus. The MyHCs of deep-sea fishes have a unique structure in two loop regions, loop-1 and loop-2, in comparison with those of non-deep-sea fishes. The loop-1 region of deep-sea fishes has a Pro residue and the loop-2 region, which is an actin-binding site, is shorter than the same region in non-deep-sea fishes. The amino acid substitution in the loop-1 region is expected to be mainly involved in ATPase activity, whereas the deletion in the loop-2 region affects the association of MyHC with actin filaments at high pressure. In addition, the MyHC of deep-sea fishes has biased amino acid substitutions at core positions in the coiled-coil structure of the rod region. These amino acid substitutions are likely to decrease the cavities in the coiled-coil structure and consequently make the structure more compact and unaffected by high pressure. Together, these results indicate that amino acid substitutions can adaptively alter the pressure sensitivity of a protein even if they do not directly influence core structure.

Amino acid sequences of alpha-skeletal muscle actin isoforms in two species of rattail fish, Coryphaenoides acrolepis and Coryphaenoides cinereus

SUMMARY: The cDNA clones of α-skeletal actins were isolated from the skeletal muscle of two species of rattail fish, Coryphaenoides acrolepis and Coryphaenoides cinereus. The complete nucleotide sequences of the cDNA and their deduced amino acid sequences were determined. Each of the two species had two α-skeletal actin cDNA. The nucleotide sequences of the coding region of the two α-skeletal actin isoform genes within each species had 92.0 and 91.8% homology. From the cDNA sequences of the four α-skeletal actin isoforms in the two species, amino acid sequences of 377 amino acid residues were deduced. It was predicted that the two N-terminal amino acid residues of each protein are processed after translation. The amino acid sequences of α-skeletal actin 1 in the two Coryphaenoides species were identical, as were the amino acid sequences of α-skeletal actin 2 in the two species. The amino acid sequences of the two α-actin isoforms, α-skeletal actin 1 and α-skeletal actin 2, differed by only a single amino acid, Ala/Ser at the 155th position. Northern blot analysis showed that a similar amount of each of the two α-actin isoform mRNA was expressed in the skeletal muscle of the two Coryphaenoides species.

A possible new control mechanism suggested by resonance Raman spectra from a deep ocean fish hemoglobin

The rattail fish, Coryphaenoides armatus, lives at ocean depths of 3000 m. As an adaptation for pumping oxygen into the swim bladder against the extreme pressures at the ocean bottom, the hemoglobin from this fish at low pH exhibits an extraordinarily low affinity for ligands. In this study, continuous wave and time-resolved Raman techniques are used to probe the binding site in this hemoglobin. The findings show an association between the low-affinity material and a highly strained heme-proximal histidine linkage. The transient Raman studies reveal differences in the protein structural dynamics at pH 6 and 8. The emerging picture derived from both this and earlier studies is that in vertebrate hemoglobins the heme-proximal histidine linkage represents a key channel through which species- and solution-dependent variations in the globin are communicated both statically and dynamically to the heme to produce an extensive range of ligand binding properties. Also presented is a new model that relates both intensity and frequency of the resonance Raman band involving the iron-proximal histidine stretching mode to specific protein controlled structural degrees of freedom. There emerges from this model a mechanism whereby modifications in the proximal heme pocket can further reduce the affinity of an already highly strained T state structure of hemoglobin.

Physical and biological factors affecting the behaviour and mortality of hydrothermal vent tubeworms (vestimentiferans)

Vestimentiferan tubeworms of two hydrothermal vents on Juan de Fuca Ridge, northeast Pacific, were photographed with a time-lapse camera over periods of 1, 5 and 26 days and supplemented with video for 25 min. Current and turbidity measurements were also made. Mortality of the worms was heavy: 44% of the worms studied in the 26-day period were removed by falling sulphate/sulphide spires or died for other reasons. Predation effects are very common among collected specimens and implicate the activities of photographed rat-tail fish and polynoid polychaetes. Time-lag auto-correlations reveal a discernible semidiurnal and diurnal periodicity in the retraction/extension movements of the vestimentiferan population. However, no direct correlation exists with measures of surrounding currents or suspended particulates that have clear tidal components to their periodicity. Worms in each series were examined individually but no consistent endogenous rhythm could be identified. Worms are sensitive to touch and the approach of predators and exhibit rapid retraction responses. Although they do not appear to respond to the second-to-minute scale variations in sorrounding fluids, their short-term behaviour is highly variable. Over many days, the retractions/extension profile of each worm is quite constant and perhaps is the expression of a constant metanolic rate. The two species examined differ substantially, with less than half the Ridgeia piscesae being extended at any time compared to 3/4 of the R. phaeophiale population. Periods of retraction frequenlly last more than 30 min which man produce anaerobic conditions within the tube. Uptake of dissolved gases, and thus metabolic rate, is likely affected by both the specific retraction behaviour and branchial filament loss to predators.

A new genus and species of rattail fish (Macrouridae) from the eastern North Atlantic and eastern Indian Ocean, with notes on its ecology

A new genus, Macrosmia, and species (M. phalacra) of benthopelagic macrourid fish is described from single male specimens caught in 1650–1699 m soundings in the northeastern Atlantic and south‐eastern Indian Oceans. This elongate macrourine rattail, with 7 branchiostegal and 11–12 pelvic rays, is unique in its massive olfactory organ, the cavity of which almost equals the diameter of the orbit. This cavity is a reverse D‐shape, with the posterior margin deforming the orbital rim into a D‐shape. Macrosmia has a short deep snout, lacks prominent ridges on the head, has anteriorly placed plevic fins and a weakly serrated second spinuous ray in the first dorsal fin. The anus is contiguous with the anal fin. These characters, among others, show affinity with the Cetonurus group of genera. The distribution and diet of the species is briefly discussed and M. phalacra is shown to be at least partly dependent on benthic food which, from one example, is of crustacean origin.

DICLIDOPHORA NEZUMIAESP. N. (MONOGENEA: DICLIDOPHORIDAE) AND ITS ECOLOGICAL RELATIONSHIPS WITH THE MACROURID FISHNEZUMIA BAIRDII(GOODE AND BEAN, 1877)

Diclidophora nezumiae sp. n. is described from the gills of the rat-tail fish Nezumia bairdii (Goode and Bean, 1877) taken from the environs of Hudson Submarine Canyon in the northwest Atlantic. The host-parasite relationships were studied in the host population. The new species is most similar to small species of Diclidophora having short bodies that taper to maximum width at the level of the first pair of clamps. It may be differentiated from other species by the following: clamps wider than long, noticeably decreasing in size posteriorly; lamellate extension of sclerite b does not fuse with sclerite c1; unsclerotized diaphragm; a relatively small clamp sucker; 10-13 cirrus hooks; 18-30 intercecal, postovarian testes; unlobed seminal receptacle; filamented eggs; and body dimensions. Of 378 N. bairdii specimens examined, 106 (28%) were infected with 1-21 D. nezumiae per host. The parasite occurred most frequently on filaments of the first gill arch. Infected fish ranged from 61-428 mm in total length. They were collected at depths of 300-1900 m. Both incidence and intensity of infection were greater for hosts collected between 700-1000 m. Depth of capture of the host was more strongly correlated with fish abundance than with fish size.

On the identity and pelagic occurrence of larval and juvenile stages of rattail fishes (family macrouridae) from 60°N, 20°W and 53°N, 20°W

Abstract A rare opportunity to study the early life history of some macrourid fishes arose from midwater discrete depth collections over soundings of 2700 to 2800 m during April and May, 1971. Seven juveniles, all caught at 60°N, were identified as Coryphaenoides (Coryphaenoides) rupestris (four from 700 to 900 m), C. (Coryphaenoides) guntheri (two from 800 to 1250 m) and C. (Lionurus) carapinus (one from 1500 to 2000 m). In addition, 60 larvae were collected, 28 C. (C.) rupestris (19 from 60°N, 25 to 800 m and nine from 53°N, 300 to 900 m and 32 specimens of C. (Lionurus) species, designated as sp. A (one from 60°N, 50 to 100 m and 24 from 53°N, 10 to 600 m) and sp. B (six from 53°N, 25 to 600 m) and one specimen of doubtful affinity (from 53°N, 600 to 700 m depth). The depth distribution of both juveniles and larvae is shown, with no indication of diurnal vertical migration. A positive correlation between living depth and size among the larvae is confirmed. An attempt to verify a similar correlation between living depth and the length of the retia mirabilia in the larval swimbladder suggested that retial growth conformed more closely to body growth than to living depth. Other developmental trends in the larvae are described. Food remains were absent from the juveniles, but selected larvae of all species examined were eating copepods only. The larvae were considered to be of local origin. While the juveniles of all species occupied similar levels to the adult peak depth range, those of C. (C.) rupestris were some 70 miles away from slopes of equivalent depth. The ecological implications of reproductive strategies similar to that of the macrourids among bottom-living deep-sea fishes are considered.

A systematic review of the rattail fishes (Macrouridae: Gadiformes) from Oregon and adjacent waters

A systematic review of the rattail fishes (Macrouridae: Gadiformes) from Oregon and adjacent waters

The Adaptation of Enzymes to Pressure II. A Comparison of Muscle Pyruvate Kinases from Surface and Midwater Fishes with the Homologous Enzyme from an Off-Shore Benthic Species

SYNOPSIS. Pyruvate kinase (PK) maximum catalytic rate is dramatically decelerated by increasing hydrostatic pressure. In four different species inhabiting different portions of the water column, muscle pyruvate kinase displays (1) a reduction in the volume change of activation, Δ V *. a t higher temperatures, (2) a pH independence of Δ V *, and (3) a general increase in the activation energy at increased pressures. Although shared by the four different pyruvate kinases examined, none of these characteristics is critically involved in the regulation of PK catalysis. In contrast, pressure effects on another set of characteristics, all vitally important to control of PK catalytic function, depend upon the species origin of the enzyme. In the case of the rainbow trout, Salmo gairdneri , high pressure dramatically reduces pyruvate kinase affinities for the two substrates (PEP and ADP), the cationic cofactor (Mg2+), and the negative modulator (ATP). The homologous muscle enzyme from Oligoplites mundus , another surface dwelling species, displays similar responses to pressure. On the other hand, muscle PK affinities for the same key regulatory ligands are much less pressure sensitive in the abyssal rattail fishes ( Coryphaenoides sp.) and are essentially pressure independent in a vertically migrating midwater sea bass, Ectreposebastes imus . In these latter two species, PK catalytic rates under probable physiological conditions are determined largely by these kinetic properties rather than by energy-volume parameters.

Pressure Effects on Cholesterol and Lipid Synthesis by the Swimbladder of an AbyssalCoryphaenoidesSpecies

SYNOPSIS. The swimbladder gas gland is recognized as a cholesterol synthesis site in abyssal rattail fishes, Coryphaenoides sp. (from 2000 m depth), and Galapagos Islands surface fish, Orthopristis forbesi, Seriola mazatlana , and Sphoeroides annulatus . This relates to high levels of cholesterol in the gas gland (up to 21% of lipid) and high cholesterol levels in the fatty swimbladder interior (up to 49% of lipid). The gas gland has more protein (45.4%) than the internal fatty mass (18%). Lipids synthesized include phospholipids and triglycerides in 2:1 ratio in the gas gland and 1:2 ratio in the liver. Deep fish have fatty livers (66%) compared to shallow fish (28%). Shallow fish incorporated five times as much acetate-l-14C into lipids as did deep fish, and seven to eight times as much acetate-l-14C into cholesterol. Pressure facilitation of cholesterol synthesis was observed in gas gland and liver of O. forbesi and Coryphaenoides , whereas total lipid synthesis was inhibited by higher pressures. Optimal acetate-l-14C incorporation into lipids occurred at 5000 psi and 2°C in Coryphaenoides ; it occurred at 14.7 psi and 15° in O. forbesi . These conditions closely approximate the environment of the fish.