Functional morphology of the luminescence system of Siphamia versicolor (Perciformes: Apogonidae), a bacterially luminous coral reef fish

Previous studies of the luminescence system of Siphamia versicolor (Perciformes: Apogonidae) identified a ventral light organ, reflector, lens, duct, and a ventral diffuser extending from the throat to the caudal peduncle. The control and function of luminescence in this and other species of Siphamia, however, have not been defined. Morphological examination of fresh and preserved specimens identified additional components of the luminescence system involved in control and ventral emission of luminescence, including a retractable shutter over the ventral face of the light organ, contiguity of the ventral diffuser from the caudal peduncle to near the chin, and transparency of the bones and other tissues of the lower jaw. The shutter halves retract laterally, allowing the ventral release of light, and relax medially, blocking ventral light emission; topical application of norepinephrine to the exposed light organ resulted in retraction of the shutter halves, which suggests that operation of the shutter is under neuromuscular control. The extension of the diffuser to near the chin and transparency of the lower jaw allow a uniform emission of luminescence over the entire ventrum of the fish. The live aquarium‐held fish were found to readily and consistently display ventral luminescence. At twilight, the fish left the protective association with their longspine sea urchin, Diadema setosum, and began to emit ventral luminescence and to feed on zooplankton. Ventral luminescence illuminated a zone below and around the fish, which typically swam close to the substrate. Shortly after complete darkness, the fish stopped feeding and emitting luminescence. These observations suggest that S. versicolor uses ventral luminescence to attract and feed on zooplankton from the reef benthos at twilight. Ventral luminescence may allow S. versicolor to exploit for feeding the gap at twilight in the presence of potential predators as the reef transitions from diurnally active to nocturnally active organisms. J. Morphol., 2011. © 2011 Wiley‐Liss, Inc     

Symbiosis initiation in the bacterially luminous sea urchin cardinalfish Siphamia versicolor

To determine how each new generation of the sea urchin cardinalfish Siphamia versicolor acquires the symbiotic luminous bacterium Photobacterium mandapamensis, and when in its development the S. versicolor initiates the symbiosis, procedures were established for rearing S. versicolor larvae in an aposymbiotic state. Under the conditions provided, larvae survived and developed for 28 days after their release from the mouths of males. Notochord flexion began at 8 days post release (dpr). By 28 dpr, squamation was evident and the caudal complex was complete. The light organ remained free of bacteria but increased in size and complexity during development of the larvae. Thus, aposymbiotic larvae of the fish can survive and develop for extended periods, major components of the luminescence system develop in the absence of the bacteria and the bacteria are not acquired directly from a parent, via the egg or during mouth brooding. Presentation of the symbiotic bacteria to aposymbiotic larvae at 8-10 dpr, but not earlier, led to initiation of the symbiosis. Upon colonization of the light organ, the bacterial population increased rapidly and cells forming the light-organ chambers exhibited a differentiated appearance. Therefore, the light organ apparently first becomes receptive to colonization after 1 week post-release development, the symbiosis is initiated by bacteria acquired from the environment and bacterial colonization induces morphological changes in the nascent light organ. The abilities to culture larvae of S. versicolor for extended periods and to initiate the symbiosis in aposymbiotic larvae are key steps in establishing the experimental tractability of this highly specific vertebrate and microbe mutualism.     

Ostorhinchus yamato,a new species of cardinalfish (Perciformes: Apogonidae) from Japan

Ichthyological Research - The new cardinalfish Ostorhinchus yamato sp. nov. is described on the basis of 135 specimens collected from Japan. The new species resembles Ostorhinchus gularis (Fraser...     

A new species of the cardinalfish genus Gymnapogon (Perciformes, Apogonidae) from the Red Sea

 A new cardinalfish species, Gymnapogon melanogaster, is described from two specimens collected at night in the Gulf of Aqaba, Eilat, Israel. This species is characterized by having 9 dorsal and 8 anal fin soft rays; 14–15 pectoral fin rays; 2 + 11 gill rakers; a flat, bifurcated preopercular spine; a naked body without a papillae network; black pelvic fins; and a black stomach. It is similar to Gymnapogon vanderbilti (Fowler, 1938) that is known only from the Line Islands of the Central Pacific Ocean. Received: December 26, 2001 / Revised: June 10, 2002 / Accepted: June 24, 2002 Acknowledgments We thank D. Didier and M. Sabaj of the Academy of Natural Sciences, Philadelphia, for loans of and for taking data from type specimens; T.H. Fraser of the Mote Marine Laboratory, Sarasota, kindly provided data on type specimens. We are grateful to E. Heemstra of the South African Institute for Aquatic Biodiversity, Grahamstown, South Africa, for the artwork presented in this article and to A. Lerner of the Hebrew University, Jerusalem, for his assistance in collecting the specimens. Correspondence to:Ofer Gon     

Life history of the Hawaiian blackhead triplefin, <Emphasis Type="Italic">Enneapterygius atriceps</Emphasis>(Blennioidei,Tripterygiidae)

Synopsis We described aspects of the life history of the small, cryptic, triplefin blenny, Enneapterygius atriceps, collected from the mouth of Kaneohe Bay, Oahu, Hawaii. We examined otolith microstructure to construct a von Bertalanffy growth curve, described a length–weight relationship, performed a detailed dietary analysis, used standard histological techniques to determine size at maturity and reproductive patterns, determined batch fecundity, and used an index of gonadal development to examine spawning seasonality. Enneapterygius atriceps is a remarkably short-lived species with low fecundity and a short, well-defined breeding season. Dietary analysis suggests this fish lives and feeds around the bases of dead coral heads. This study generated the first otolith-based growth curve for any member of the Tripterygiidae.     

LuxA gene of light organ symbionts of the bioluminescent fish Acropoma japonicum (Acropomatidae) and Siphamia versicolor (Apogonidae) forms a lineage closely related to that of Photobacterium leiognathi ssp. mandapamensis

A molecular phylogenetic analysis of luxA gene sequences of light organ symbionts of the fish Acropoma japonicum (Acropomatidae) and Siphamia versicolor (Apogonidae) revealed that the sequences were related to those of Photobacterium leiognathi ssp. mandapamensis, which is not known to occur as a light organ symbiont among bioluminescent P. leiognathi clades. The presence of another lux gene element, luxF, coding for nonfluorescent protein, provided additional support for the identity of the light organ symbionts of the fish. Cladogenesis of the light organ symbiont P. leiognathi may be influenced by the radiation of host fishes.     

Life history variation among female surfperches (Perciformes: Embiotocidae)

Synopsis Life history variation within the family Embiotocidae is extensive and involves differences in age of first reproduction, fecundity schedules, growth rates, longevity and size of young. Based on maximum reported body lengths, there are three distinct size groups among the family's 23 species. Small species do not exceed 215 mm TL, medium-size species attain 275 to 335 mm TL, and the large species attain 380 to 470 mm TL. The longevity oh surfperches varies from two to ten years, growth is indeterminate, and females of the medium-and large-size groups may delay first reproduction beyond age one. With one exception, all species show increasing length-specific fecundities. The life history characteristics of females differ among the three size groups. Relative to smaller species, the largest species have moderately high fecundity, delayed maturity and long life. Medium-size species have low fecundity, may delay maturity for 1 to 3 years and have intermediate life spans. Small species have generally higher, but variable, fecundity, do not delay maturity, and are short lived. Among the small North American species, the trend in fecundity varies inversely with environmental predictability. Fecundity is highest in the species which occupies highly seasonal freshwater environments. Coastal species produce moderately large broods and species which occupy stable deep water environments produce the smallest broods.     

Rhabdamia novaluna,a new species of cardinalfish (Perciformes: Apogonidae) from the western Pacific Ocean,with comments on the synonymy of Rhabdamia gracilis

Ichthyological Research - The new cardinalfish Rhabdamia novaluna sp. nov. (Apogonidae) is described on the basis of 79 specimens collected from the western Pacific Ocean. The new species is most...     

Life history of the blackspotted whipray Himantura astra

Features of the life history of Himantura astra from north-east Australia were examined including its age and growth, reproduction and diet. Centrum edge and marginal increment ratio analyses were used to validate annual band formations with the Gompertz growth function providing the best fit to male (W(D∞) = 722·7 mm, k = 0·104) and female (W(D∞) = 821·8 mm, k = 0·073) disc width (W(D))-at-age data. At 29 years, the maximum age of females was higher than males (18 years). Sizes at 50% sexual maturity (W(D50)) for males and females were 469·3 and 462·3 mm, respectively. Ages at sexual maturity (A(M50)) were reported at 7·32 (males) and 8·67 (females) years. An index of relative importance (I(RI)) revealed carid shrimps (77·9%), brachyurans (12·1%) and stomatopods (4·9%) as the most important prey groups, with prey diversity increasing with W(D) from 0·92 to 1·63 (Shannon-Weiner index). This study provides significant insights into the biology of H. astra and contributes to the ongoing development of fisheries-based risk assessments for this species.     

Apogon smithi (Kotthaus, 1970) (Teleostei: Apogonidae), a Red Sea cardinalfish colonizing the Mediterranean Sea

Smith's cardinalfish Apogon smithi is recorded for the first time in the Mediterranean Sea. Six specimens were caught by commercial trawler north of Jaffa, Israel, at depths of 40 m and the relatively high number of specimens suggests that A. smithi has established a sustainable population. This is the third Indo-Pacific apogonid species documented in the Mediterranean Sea, and is assumed to be a migrant originating from the Red Sea.     

Life history of the Western Crested Loach <Emphasis Type="Italic">Paracobitis malapterura</Emphasis> in the Zarrin-Gol River,East of the Elburz mountains (Northern Iran)

A total of 370 specimens of Paracobitis malapterura in the Zarrin-Gol River (east of the Elburz Mts, Iran) were caught by regular monthly collection throughout one year from November 2006 to October 2007. The specimens were then examined for age and growth, reproduction and feeding attributes. Based on otolith readings the maximum ages of the population observed were 3⁺ years for males and 4⁺ years for females. The specimens ranged in size from 38 to 130 mm total length, weighing from 0.68 to 30.55 g total weight. Length-weight relationship was estimated as W = 0.020L ^2.62 for males, W = 0.002L ^3.81 for females and W = 0.008L ^3.08 for the population. Sex ratio was 1: 1.27 in favor of females. The Gonadosomatic index indicated that reproduction of the loach in the river occurred around April–May, with the highest average value of 1.48 for males and of 5.36 for females in May. The absolute fecundity ranged between 92–1180 eggs with a mean of 456.31 eggs. Diameter of oocytes ranged from 0.11 to 2.80 mm with a mean value of 0.95 mm. The absolute fecundity and oocyte diameter to fish size (length and weight) and age were not significantly correlated. Plecoptera and Trichoptera dominated the diet contents composing 72.43% and 20.80% of total frequency of food items, respectively.     

Life history traits and temporal trends of abundance of the orange-spotted trevally (Carangoides bajad) from Saudi waters of the Gulf

In this study we lay the groundwork for sustainability-oriented fisheries management, by estimating parameters the life history of orange-spotted trevally Carangoides bajad as well as trends of abundance in coral-reef habitats. We observed a new record of maximum size of 720 mm fork length. Carangoides bajad is a moderately long-lived (14 years) and slow-growing (K = 0.085 year⁻¹) carangid species, closer to a K-selection species, with higher vulnerability to fishing and lower rates of recovery when the population level is low. Growth and biological composition in terms of length and age categories do not differ between the sexes, but females become mature faster. Reproductively active months (May–August) overlapped with those from Emirati waters further south. The abundance index showed a pronounced drop during 1990–1993, possibly in connection with habitat deterioration during the Gulf War (1990–1991) oil spill. The index increased gradually from 1994 and has fluctuated close to the reference level of 1985 up to the present. Considering the findings of large-sized and old-age individuals and abundance index from coral reefs close to its level three decades back, the C. bajad stock in the western part of The Gulf appears to be in healthy exploitation status despite growing harvesting rates.     

Life history of Gambusia holbrooki (Pisces, Poeciliidae) in the Ebro delta (NE Iberian peninsula)

We studied age, growth and reproduction of an introduced poeciliid, Gambusia holbrooki (Agassiz, 1859), in the Ebro delta marshes. Maximum ages observed were 2⁺ in females and 0⁺ in males. Growth commenced in March and continued until September. Females reached greater sizes, had a higher rate of growth and lived longer than males. The largest sizes found were 63 mm versus 32 mm . Multiple spawning occurred throughout the reproductive cycle (from May to September). The average brood size per female reached its maximum in July in the parental cohort (86 embryos/) and in August in the offspring cohort (29 embryos/). After reproduction the parental cohort decreased drastically. The relationship between fecundity (F) and total length (mm) was calculated for each month of the reproductive period. Sex-ratio deviated significantly from unity.Viviparity, several broods and large larvae provide G. holbrooki with several advantages over oviparous species. The capacity to adjust its life history to a particular environment could explain the life history differences between those in the Ebro delta and other populations.     

Life history and ecology of seahorses: implications for conservation and management

We present the first synthesis of the life history and ecology of seahorses, compare relationships for seahorses with other marine teleosts and identify research needs. Seahorses occurred primarily amidst temperate seagrasses and tropical coral reefs. Population densities were generally low, ranging from 0 to 0·51 individuals m^?2, but reached 10 m^?2 in some patches. Inferred life spans ranged from 1 to 5 years. Seahorses consumed live prey and possibly changed diet as they grew. Growth rates are poorly investigated to date. Reproduction and mating systems are the best‐studied aspects of seahorse ecology. The relationship between size at first maturity and maximum size in seahorses conformed to that for other marine teleosts. All seahorse species were monogamous within a cycle, but some were polygamous across cycles. Direct transfer of clutches to the brood pouch of the male fish made it difficult to measure clutch size in live seahorses. After brooding, males released from c. 5 to 2000 young, depending on species and adult size. Newborn young measured from 2 to 20 mm in length, which was a narrower size range than the 17‐fold difference that occurred in adult size. Newborn body size had no relationship to adult size. Both eggs and young were larger than expected among marine teleosts, even when considering only those with parental care, but brood size at release was lower than expected, perhaps because the young were more developed. The size of adults, eggs and young increased with increasing latitude, although brood size did not. Considerable research is needed to advance seahorse conservation and management, including (a) fisheries‐dependent and fisheries‐independent abundance estimates, (b) age‐ or stage‐based natural and fishing mortalities, (c) growth rates and age at first maturity, and (d) intrinsic rates of increase and age‐ or size‐specific reproductive output. Current data confirm that seahorses are likely to be vulnerable to high levels of exploitation.     

Biology of the cardinalfishGlossamia gjellerupi (Perciformes: Apogonidae) from the Sepik-Ramu River basin,Papua New Guinea

Synopsis Glossamia gjellerupi forms a considerable part of the fish biomass (25%) and density (12%) in floodplain margin streams and lower foothill streams throughout the Sepik-Ramu basin where it occurs up to an altitude of 320 meters above sea level. It prefers habitats with slow flow rates: pools, alongside banks, under cover of vegetation, etc. Biomass and density decreased with increasing current speeds. Condition factor and fat deposits were negatively correlated to current speeds, with populations from floodplain margin streams having the highest averages for both these indices. Fluctuations in population size appeared to be related to the irregular occurrence of spates. No seasonality in reproduction, condition and fat deposits were noted although peaks occurred according to specific local conditions. Fecundity was found to be low, increasing with fish size. Eggs in a ripe ovary were all in the same stage of development, with sizes of around 3.3 mm.G. gjellerupi is a male mouth brooder. Mouth-breeding may restrict the species to well oxygenated waters. Reproductive activity takes place throughout the year but is not random since clear peaks in gonad development occurred within different populations. Reproductive activity and/or survival rate of juveniles are possibly directly related to floods. Prolonged periods of environmental stability, such as those occurring in periods of less rainfall, seem to be conditional for the survival of juveniles. Fish up to 30 mm length fed predominantly on small benthic insect larvae. Fish larger than 60 mm are carnivorous top-predators feeding predominantly on crabs, bottom dwelling fish and large terrestrial insects. Fish of all sizes, except the largest, fed on caridinid prawns. Feeding habits varied between different habitats depending on local environmental conditions.     

A new cardinalfish, <Emphasis Type="Italic">Verulux solmaculata</Emphasis> (Perciformes: Apogonidae), from Papua New Guinea and Australia

Verulux solmaculata sp. nov., a new cardinalfish based on 88 specimens collected from Papua New Guinea and Australia, differs from V. cypselurus, the only other known member of the genus, by the following characters: higher modal numbers of pectoral fin-rays (16 vs. 15 in the latter) and developed gill rakers (14 vs. 13), a broader black band extending over 3–5 (mode 4) rays on each lobe of the caudal fin (vs. 1–3, mode 2), and a black blotch on the caudal-fin base (vs. blotch absent).     

Dietary influence on the biology and metabolism of Isotoma viridis (Collembola)

(1) Two groups of individually cultured Isotoma viridis were studied. They were given a diet of Tetramin fishfood and Pleurococcus algae respectively, in order to monitor individual changes in oxygen uptake during culture. (2) Growth rate, moulting frequency and the maximal live weight reached were higher when fed on Tetramin. (3) Egg production in the culture fed Pleurococcus was twice that fed on Tetramin, due to the more fertile intermoult periods without oviposition in animals fed Tetramin. The egg quality seemed to be lowered in the algae-fed animals rather less than in those fed with fishfood. (4) In both cultures, an increase of 35–40% of the metabolic rate at the start of the experiment was observed. This increase was maintained with a Tetramin diet, whilst it disappeared in cultures fed Pleurococcus. The F₁ generation of both groups showed an increased metabolic rate, that from Tetramin-fed being significantly higher than that from Pleurococcus-fed animals. (5) It is suggested that the initial increase in metabolism is a result of excess food, and the increased level of oxygen uptake in animals on a Tetramin diet the result of inadequacy of the composition of the fishfood for egg production, thus channelling the energy uptake mainly into growth and metabolism. (6) Neither Tetramin nor Pleurococcus are considered to provide an adequate diet for I. viridis, as reproductive success differed considerably from field conditions.     

Insights of the life history in the porcellanid crab Petrolisthes armatus (Gibbes, 1850) (Crustacea: Anomura: Porcellanidae) from the Southwestern Atlantic coast

Petrolisthes armatus (Gibbes, 1850) life history was evaluated based on growth and reproduction. Specimens were captured at Ubatuba (Brazil), identified, sexed and measured: carapace (CL, length; CW, width), larger cheliped propodus (PL, length; PW, width; and PH, height), and 2th and 5th abdominal somite (AW₂ and AW₅, width). Relative growth was studied using CL as independent variable and its relation with other variables (dependents), to estimate puberty size and morphological maturity. Fecundity was represented by number of eggs vs. body size CL, with a better fit using a power function. Considering the 257 specimens analyzed, males were larger than females, and the overall sex ratio was 1:1, with some differences among size classes. Maturity (puberty size) was revealed by: AW₂ × CL (males: 8.6 mm CL; females: 7.6 mm CL); and AW₅ × CL (7.1 and 7.6 mm CL, respectively). Reproduction was continuous, but more intense in rainy season and recruitment occurring in dry season. Fecundity of this species was 228 ± 163 eggs, with better fit by a power function (R² = 0.72). Maturity size and growth differed when a pristine area (Ubatuba) was compared with a polluted area (São Sebastião), in the same Brazilian area (São Paulo State).