Substantial northward range extension for Gephyroberyx darwini (Berycoidei, Trachichthyidae) in the western North Atlantic, possibly explained by habitat preference

Gephyroberyx darwini , herein reported northward to Browns Bank in the western North Atlantic, may inhabit rarely sampled hard substrata in northern temperate and boreal slope waters.     

A new species of Pseudopecoelus von Wicklen, 1946 (Digenea: Opecoelidae) from the orange roughy Hoplostethus atlanticus Collett, 1889 (Trachichthyidae) from off southeastern Australia

A new species, Pseudopecoelus sewelli, is described from the deep-sea fish Hoplostethus atlanticus from off southeastern Australia. It is an elongate form with considerable variation in such important characters as the anterior vitelline extent, the sucker ratio and the egg-size. The features distinguishing this species from five related forms are combinations of the sucker ratio, egg-size, lobation of gonads, presence or absence of a cirrus-sac and the position of the genital pore.     

Early ontogeny of aquarium-raised Moenkhausia sanctaefilomenae (Characiformes: Characidae)

The ontogeny of the characiform fish Moenkhausia sanctaefilomenae, from early embryogenesis through the early larval period, is presented. Fertilized eggs were slightly elliptical, measured 0.6 mm in diameter, and were surrounded by a fertilization envelope 0.8 mm in diameter. Much of the early embryogenesis is complete after 12 h, with cleavages complete after 2.5 h and gastrulation complete after 3 additional hours. The initial formation of organs needed for predatory behaviors occurs within 72 h. Growth of the cranial elements is quite dramatic and allows for the capture of relatively large prey at the onset of exogenous feeding. Elaboration of these elements continues into the early larval period.     

Spatial variation in reproduction, and occurrence of non-reproductive adults, in orange roughy, Hoplostethus atlanticus Collett (Trachichthyidae), from south-eastern Australia

This study was designed to determine whether orange roughy reproduce throughout their distribution in Australian waters, and if so, whether commencement of spawning and length at maturity vary within the region. We found that females from four widely separated sampling areas reproduced in 1988, but that the onset of spawning and length at maturity were not the same in all the areas. In New South Wales, ovulation was finished by mid-June, and 50% of females were mature at 28 cm standard length (S.L.). On the other hand, females from eastern and western Tasmania and South Australia did not spawn until mid-July, and 50% of females from Tasmania were not mature until 32 cm S.L. Females from all areas had oocytes with yolk granules at least 5 months before ovulation. However, in the few months before spawning, some adult females from all areas had not undergone vitellogenesis or were resorbing all yolky oocytes. The best estimates of the proportion of these non-reproductive females were made in March and April, when the single batch of eggs to be spawned was clearly distinguishable, and before spawning aggregations had formed. In 1990 in eastern Tasmania, at the site of a major spawning aggregation, the best estimate of the proportion of non-reproductive fish was 45%. We suggest that scarcity of food, coupled with the cost of joining a spawning aggregation, may result in intermittent spawning in this long-lived species.     

Two new soldierfishes (Beryciformes: Holocentridae:Myripristis) from Japan

Two species of the holocentrid fish genusMyripristis are described as new from Japan, both with a single pair of tooth patches outside the gape at tip of lower jaw, the third anal spine longer than the fourth, and 28–29 lateral-line scales:M. kochiensis from Kashiwa-jima, Kochi Prefecture, previously misidentified asM. murdjan, is distinct in having small scales in axil of pectoral fins, 32–36 gill rakers, interorbital space 4.45–5.1 in head, and lower jaw not strongly projecting when mouth closed;M. greenfieldi, from the Ryukyu Islands and Ogasawara Islands to Kochi Prefecture, previously misidentified asM. woodsi andM. randalli, is distinct in lacking scales in the pectoral axil, having 35–52 cteni on largest body scales, 43–47 gill rakers, and longest dorsal spine 2.0–2.25 in head.     

Early stages of vocal ontogeny in the magpie (Pica pica)

Summary The vocal repertoire of magpie (Pica pica) chicks consists of six calls: Begging Trill (BT), Soft Whistle (SW), Begging Scream (BS), Alarm Call (AC), Distress Call (DC) and Brief Contact Note (BCN). Both BT and SW have a tonal structure and their occurrence is restricted to the nestling period. At fledging, there is a gradual change from BT into BS and a sudden appearance of harsh calls similar to those of adult birds (AC, DC, BCN), without evident transitional forms with preceding tonal calls. Both the existence and the structural design of calls seem to be adapted for providing nestlings with immediate benefits linked to the two major chapters of allocation of parental care. Emission rates of BT increase with hunger motivation under laboratory conditions. Their structure suggests that they are easily located but liable to suffer from environmental degradation. BS of fledglings may be more resistant to degradation, a trait which may facilitate the identification by parents of their own offspring. Both AC and DC attract parents to defend the nest against potential predators, and their structure make them to be easily located and detectable at long distances. BCN are given by fledglings during bouts of locomotory activity (exploration and play) and they probably help in maintaining the cohesion of the group under conditions of poor visibility. In accordance, this call may be fairly located at short distances. The function of SW was unclear. It is given during periods of nestling inactivity between begging bouts, and could be easily elicited by tactile and auditory stimuli. After laboratory experiments, it is concluded that SW serve to indicate parents that nestlings are in good condition, hence to benefit from the parental willingness to invest in a brood with high prospects of survival. Since (i) there is a widespread lack of continuity in the development of adult vocalizations starting from nestling calls, and (ii) nestling calls seem to have evolved to provide birds with benefits in the short-term, these facts argue against the prevailing idea that the main function of calls early in ontogeny is to act as precursors of adult vocalizations.

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Zusammenfassung Das Lautrepertoire von Elsternestlingen besteht aus 6 Lautäußerungen: Betteltrillern (BT), Sanftes Pfeifen (SP), Bettelkreischen (BK), Alarmruf (AR), Angstschreien (AS) und kurzer Kontaktruf (KR). BT und SP sind tonal und treten nur während der Nestlingsperiode auf. Zum Zeitpunkt des Ausfliegens geht BT graduell in BK über und plötzlich treten auch ohne vorausgehende tonale Übergangsformen rauhe Rufe ähnlich denen der Altvögel auf (AR, AS, KR). Sowohl die Existenz als auch die Struktur der Lautäußerungen scheinen als Anpassungen im Zusammenhang mit einer Optimierung der Brutpflege zu interpretieren zu sein. Die Emissionsrate von BT steigt unter Laborbedingungen mit der Hungermotivation. Die Struktur legt nahe, daß BT leicht geortet werden kann, aber auch leicht von der Umgebung verschluckt wird. BS der flüggen Jungen scheint davon weniger betroffen zu sein, so daß die Eltern leichter ihre Jungen identifizieren können. AR und AS veranlassen die Altvögel, ihr Nest gegenüber potentiellen Prädatoren zu verteidigen; die Struktur der Laute begünstigt ihre Ortung und Wahrnehmung über größere Entfernungen. KR werden von den flüggen Jungen bei lebhafter lokomotorischer Aktivität (Exploration, Spiel) geäußert; sie tragen vielleicht dazu bei, die Gruppe auch unter erschwerten optischen Kontaktmöglichkeiten zusammenzuhalten. Die Funktion von SP blieb unklar. SP war während inaktiver Perioden zwischen Bettelverhalten zu hören und konnte leicht durch taktile und akustische Reize ausgelöst werden. Nach Laborexperimenten ist zu schließen, daß SP den Eltern Wohlbefinden der Jungen anzeigt und so Bereitschaft zur Investition in eine Brut mit hoher Überlebenswahrscheinlichkeit fördert. Daß (1) zwischen den Rufen der Altvögel und dem Repertoire der Nestlingen weitgehend keine kontinuierlichen Übergänge festzustellen und (2) Nestlingsrufe offensichtlich im Hinblick auf kuzfristige Gewinne zu interpretieren sind, spricht gegen die allgemein vorherrschende Ansicht, das Lautrepertoire in frühen Stadien der Ontogenie sei hauptsächlich ein Vorläufer der Adultlaute.

     

Early ontogeny of Lophonectes gallus (Bothidae) from southeastern Australia

 The early ontogeny of Lophonectes gallus (Bothidae) is described based on 83 specimens (1.9–17.5 mm BL), collected from the Tasman Sea off southeastern Australia. The larvae are diagnosed by the following array of characters: vertebrae 10 + 30–31 = 40–41; one elongated dorsal fin ray and several melanophores present on gut in preflexion stage (1.9–4.7 mm BL); and spines on posterior basipterygial process, and urohyal, cleithrum, and epiotic without spines after postflexion stage (8.0–17.5 mm BL). The larvae are relatively small at metamorphosis (15–18 mm BL) compared with other bothid larvae. Received: March 22, 2001 / Revised: December 12, 2001 / Accepted: December 26, 2001     

Variation in lipid composition of some deep-sea fish (Teleostei: Oreosomatidae and Trachichthyidae)

The lipid, fatty acid and fatty alcohol compositions were determined for muscle samples from six species of deep-sea oreo collected from Australian waters; namely Neocyttus rhomboidalis, Neocyttus sp., Allocyttus verrucosus, Allocyttus niger, Pseudocyttus maculatus, and Oreosoma atlanticum. Neocyttus helgae, landed in North Atlantic waters, was also analysed. Similar analyses were also carried out on the muscle and swim bladder of the orange roughy Hoplostethus atlanticus from both Australian and North Atlantic waters. Orange roughy is currently a major commercial species in southern Australia and is a new-fishery in the North Atlantic; there are four species of oreo of increasing commercial significance in Australia due to orange roughy quota reductions. It is therefore necessary to determine if the oreo fishing industry is capable of supplementing the current orange roughy requirements with respect to muscle and oil demand. In the oreos, the mean lipid content ranged from 0.5 to 3% of wet weight, with a mixed lipid composition including wax ester, triacylglycerol, sterol and polar lipid. The ratio of the monounsaturated fatty alcohols 22:1 to 20:1 allowed samples from the two geographical regions to be distinguished. Total wax ester in muscle from North Atlantic male orange roughy was much higher than in Australian fish (27 vs. 8.5% wet weight, respectively); females from both locations contained similar amounts of wax ester (4.5 vs. 3.3%, respectively). Selected swim bladders from North Atlantic and Australian orange roughy show similar wax ester content (90 vs. 82%, respectively). The ratio of 22:1 to 20:1 fatty alcohols in orange roughy from the two regions was 0.5 (Australian) and 1.4 (North Atlantic). Indeed differences exist between oreos from the two locations, but not between orange roughy and this requires further investigation. With respect to the nutritional value, the oreos are more attractive than the orange roughy however lipid levels remain much lower compared with other popular species.     

Ultraviolet absorbance of the mucus of a tropical damselfish: effects of ontogeny, captivity and disease

The ultraviolet (UV) absorbance of the mucus of a Great Barrier Reef damselfish Pomacentrus amboinensis was investigated with regard to ontogeny and time spent in captivity. The UV absorbance of P. amboinensis mucus increased with fish size and decreased with time spent in captivity. The wavelength of maximum absorbance of the mucus did not change with fish size, but shifted towards shorter wavelengths with increasing time spent in captivity. The UV absorbance of the mucus of fish with 'fin rot' was compared to that of similar healthy individuals, and a significant decrease in UV absorbance of unhealthy fish mucus was detected; no wavelength shifting occurred. Pomacentrus amboinensis appears to sequester mycosporine-like amino acids from the diet in order to protect epithelial tissues from UV damage, and decreases in UV absorbance in captive fish were probably due to insufficient dietary availability.     

Notes on the biology,taxonomy, and distribution of flashlight fishes (Beryciformes: Anomalopidae)

New information concerning the distribution and biology of anomalopid fishes is presented. There are five valid described species:Anomalops katoptron andPhotoblepharon palpebratus, widely distributed in the central and western Pacific Ocean;P. steinitzi from the Red Sea and Comoro Islands;Kryptophanaron alfredi from the Caribbean; andK. harveyi from Baja California.P. steinitzi differs fromP. palpebratus in coloration, head bone ornamentation, and pelvic ray number. The second known specimen ofK. harveyi is described in detail. The occurrence of large specimens ofAnomalops in deep water and small specimens in shallow water is discussed. Synonyms and a key to the species of anomalopids are provided.     

The uncultured luminous symbiont of Anomalops katoptron (Beryciformes: Anomalopidae) represents a new bacterial genus

Flashlight fishes (Beryciformes: Anomalopidae) harbor luminous symbiotic bacteria in subocular light organs and use the bacterial light for predator avoidance, feeding, and communication. Despite many attempts anomalopid symbionts have not been brought into laboratory culture, which has restricted progress in understanding their phylogenetic relationships with other luminous bacteria, identification of the genes of their luminescence system, as well as the nature of their symbiotic interactions with their fish hosts. To begin addressing these issues, we used culture-independent analysis of the bacteria symbiotic with the anomalopid fish, Anomalops katoptron, to characterize the phylogeny of the bacteria and to identify the genes of their luminescence system including those involved in the regulation of luminescence. Analysis of the 16S rRNA, atpA, gapA, gyrB, pyrH, recA, rpoA, and topA genes resolved the A. katoptron symbionts as a clade nested within and deeply divergent from other members of Vibrionaceae. The bacterial luminescence (lux) genes were identified as a contiguous set (luxCDABEG), as found for the lux operons of other luminous bacteria. Phylogenetic analysis based on the lux genes confirmed the housekeeping gene phylogenetic placement. Furthermore, genes flanking the lux operon in the A. katoptron symbionts differed from those flanking lux operons of other genera of luminous bacteria. We therefore propose the candidate name Candidatus Photodesmus (Greek: photo = light, desmus = servant) katoptron for the species of bacteria symbiotic with A. katoptron. Results of a preliminary genomic analysis for genes regulating luminescence in other bacteria identified only a Vibrio harveyi-type luxR gene. These results suggest that expression of the luminescence system might be continuous in P. katoptron.     

Reproduction of pike-perch (Stizostedion lucioperca) in captivity

A natural controlled spawning of pike-perch is suggested as the prevailing method providing good results in terms of embryo survival and fry production. Techniques of hormonal induction combined with water temperature manipulation are progressively developed. The eggs are most commonly incubated with the 'nest', or in Zug jars in the case of artificial fertilization. The larvae are then transferred into specific containers for their yolk absorption. The success rate from egg to free-swimming fry is 60–70%.     

蓬莱玉参早期发育的形态学观察

本研究对仿刺参(Apostichopus japonicus)的一个特殊品系蓬莱玉参产卵、受精及胚胎和幼体发育过程进行显微观察,并与普通仿刺参进行比较。在19~21℃水温下,蓬莱玉参受精卵分别在受精12 min和24 min后释放第一、二极体,1 h后卵裂成2细胞期,之后每30 min左右完成一次卵裂,6 h后进入囊胚期,19 h后发育成原肠胚;40 h后进入耳状幼体阶段,在其后侧臂的一端出现一个不规则形的石灰质骨片,并发现其位置与水体腔处于同一侧这一规律;5 d和8 d后发育为中耳状幼体和大耳状幼体,10 d后变态发育为樽形幼体,骨片由不规则状发育为齿轮状,并出现第二个石灰质骨片;12 d后发育为五触手,14 d后发育成稚参,40 d后发育为幼参。蓬莱玉参胚胎和幼体发育时序与当前已报道的仿刺参无显著差异,但从幼参开始蓬莱玉参通体始终为白色,而普通仿刺参在45日龄时体表局部出现色素,疣足处较为明显,60日龄幼体一半以上全身布满色素。蓬莱玉参因通体纯白色而受到了众多养殖企业和研究领域的关注,本文的结果为其今后的研究奠定了可靠的理论基础。     

Bobcat (Lynx rufus) breeding in captivity: the importance of environmental enrichment

Environmental enrichment is an improvement in the biological functioning of nonhuman animals in captivity resulting from modifications to their environment; however, specifying appropriate and practical measures of enrichment is problematic. This study analyzes the behavior of 4 bobcats (Lynx rufus) in the Jerez Zoo before and after the application of a global program of environmental enrichment that included (a) changes in the size and complexity of their installations, (b) the introduction of new objects into compounds, (c) changes in diet, and (d) modifications in the grouping of animals. A factorial correspondence analysis showed a highly significant relationship among individual animals, behavior, and experimental design. Behaviors such as locomotion, repeated pacing, vigilance, and grooming more often occurred before enrichment, whereas exploratory and food behaviors were more often associated with the enrichment phase. After the implementation of the enrichment program, the bobcats bred successfully for the first time since their arrival in the zoo.     

Early ontogeny of Adinia xenica (Pisces,Cyprinodontiformes): 1. The development of embryos in hiding

Synopsis Examination of living and stained preserved embryos of the fundulid Adinia xenica from the intertidal salt marshes of the northern Gulf of Mexico, revealed a saltatory pattern of development. Embryonic structures indicate an ability to tolerate low oxygen conditions, primarily by extensive vascularization of the large yolksac and pericardial headfold, and capillaries covering the entire body. Adhesive fibres of the chorion hold the egg to the chosen substrate, away from anoxic sediments. Prior to hatching most embryos enter a resting interval of up to four weeks, with a mean duration of 8 days (in the laboratory). Growth ceases, development is limited to some skeletal calcification, and metabolic rate, as indicated by bradycardia and yolk resorption, is greatly reduced. This step distributes hatching and recruitment over time in a variety of environmental conditions. Hatching is considered to result from a variable summation of internal and external factors; ease of its induction increases during the resting interval. Upon hatching most embryos are well developed and ready to feed exogenously, there being essentially no free-embryo phase. The considerable individual variation in timing and relative order of some ontogenic events may provide opportunities for environmentally induced heterochronies and thus assist A. xenica to develop in a range of habitats and conditions. Reproductive style includes hiding the eggs in protected locations, and a fractional spawning pattern. Consideration of this plus morphological adaptations, egg size and adhesivity places A. xenica in the reproductive guild of brood-hiding cavity spawners.     

Reproduction of the mongoose lemur (Lemur mongoz) in captivity

Responses to questionnaires sent to 20 institutions holding Lemur mongoz did not reveal which aspects of management or husbandry could account for reproductive failure in the captive population, but allowed some qualitative comparisons with data compiled for captive and wild animals. In general, reproduction has occurred initially among wild-caught specimens before tapering off, and rarely occurs in the captive F₁ generation. Data compiled by the International Species Inventory System and the International Zoo Yearbook revealed an aging captive population with no recent reproduction. No aspect of group composition, activity patterns, seasonal light regime, reproductive cycles, or diet could be linked to the lack of reproduction; and among lemurs subjected to the same conditions, some were known to reproduce while others did not. Lack of knowledge about this species and the threat of extinction for both captive and wild populations make an investigation of reproductive biology imperative. Recommendations for a research program are given.     

Reproduction in the crowned lemur (Lemur coronatus) in captivity

Four pairs of captive crowned lemurs (Lemur coronatus) were studied during their annual breeding season in order to obtain baseline data on their reproductive biology for comparison with other Lemur species and to enhance their captive breeding success. Vaginal smears, testicular measurements, and records of the Duke University Primate Center provided the presented data. During a single breeding season, females cycled an average of three times, with an average cycle length of 34 days. Cycles were detected between November and March. Vaginal estrus and copulations were limited to one day per cycle. After 125 days of gestation females gave birth to one or two young. Both sexes attained sexual maturity at an age of about 20 months. Mean male testis size peaked in late December; at the same time, three of the females experienced their first estrus. Based on all available data, there was a significant positive correlation between cycle length and gestation length in the genus Lemur.