Weight‐length relationships of 3 demersal fish species from Lebanese marine waters,eastern Mediterranean

Weight‐length relationships (WLRs) were estimated for 3 demersal species, from the Lebanese marine waters, eastern Mediterranean, namely Coelorinchus caelorhincus (Risso, 1810), Scorpaena elongata Cadenat, 1943 and Stephanolepsis diaspros Fraser‐Brunner, 1940. The specimens were collected using trammel and gill nets from June 2012 to October 2014. The values of parameter b of the WLRs W = aL^b ranged from 2.922 to 3.708. Pronounced sexual dimorphism in WLR was observed for S. diaspros and none showed a WLR‐based geographical pattern of distribution. WLRs reported in this study should be applied only within the observed length ranges.     

Comparative biology of tropical Lethrinus species (Lethrinidae): challenges for multi‐species management

Life‐history characteristics of six tropical Lethrinus species sampled from the Great Barrier Reef World Heritage Area were compared. Two species groups were identified based on fork length (L_F): large species with maximum L_F > 640 mm (longface emperor Lethrinus olivaceus, yellowlip emperor Lethrinus xanthochilus and spangled emperor Lethrinus nebulosus) and small species with maximum L_F < 480 mm (Pacific yellowtail emperor Lethrinus atkinsoni, pink ear emperor Lethrinus lentjan and ornate emperor Lethrinus ornatus). Lifespan was not correlated with L_F. Early growth for all species was rapid and similar during the first few years of life, but coefficients of the von Bertalanffy growth function varied considerably among species. Growth also differed between sexes for L. atkinsoni. Reproductive characteristics varied among species, with peak periods of spawning occurring in November to December for L. atkinsoni, July to August for L. nebulous, September to October for L. olivaceus and a protracted season for L. lentjan, although fewer samples were available for the last two species. Sex‐specific L_F and age distributions and gonad histology of L. lentjan were suggestive of a functional protogynous reproductive pattern, as observed in other lethrinids. Gonad histology indicated non‐functional protogynous hermaphroditism for L. atkinsoni and L. nebulosus. The diversity of life histories among these closely related species emphasizes the difficulty in devising single management strategies appropriate for multi‐species fisheries and illustrates the importance of understanding species‐specific life histories to infer responses to exploitation.     

Orchis patens Desf.: seed morphology of an endangered Mediterranean orchid

The loss of orchid habitats has increased the investment on orchid conservation efforts to reduce the risk of extinction of rare species. In northwestern Italy, orchids are among the most threatened of all plant groups in the region, but little is known about the biology of most of the less abundant taxa. In this study, we used light and scanning electron microscopy to characterize the morphology of the seeds of the threatened Orchis patens Desf., a declining species present in semi-natural habitats. We found a marked positive relationship between seed size and embryo size that may be not restricted to O. patens but also occur in other orchid species. The comparative analysis of the observed seed traits revealed hidden morphological affinities at the reproductive level among O. patens and the three subspecies of O. mascula, showing the potential of this approach to test the taxonomic relationships among the different taxa included in the genus Orchis.     

Population biology of the little gulper shark Centrophorus uyato in Lebanese waters

A total of 38 individuals of the heavily exploited little gulper shark Centrophorus uyato were collected from Lebanese coastal waters using bottom longlines and trammel nets of different meshes at depths ranging from 115 to 600 m between May 2013 and February 2014. Their total lengths were between 45 and 94 cm and their total mass was from 870 to 6700 g. The sex ratio was not significantly different from 1:1, with 20 males and 18 females, but bathymetric sexual segregation occurred. Catch per net setting (CNS) was used as a relative abundance index to detect spatial distribution; trammel nets showed largest CNS ranging from 4·9 to 5·45 kg per unit effort in the north and south, at depths from 120 to 200 m, during spring and summer. The mass–length relationships demonstrated negative allometric growth (b < 3) (males: M_T = 0.3585L_T^2·071, r² = 0·94; females: M_T = 0.0239L_T^2·735, r² = 0·64). The condition factor as well as the gonado‐somatic and hepato‐somatic indices of C. uyato in the study area were also calculated. The results are discussed in relation to the distribution, growth and reproduction as well as the management of C. uyato.     

The evolution of reproductive strategies in dasyurid marsupials: implications of molecular phylogeny

Dasyurid marsupials show a remarkable diversity of reproductive patterns ranging from aseasonal polyoestry to restricted annual breeding in which males synchronously die after a brief mating season. Previous studies have categorized dasyurid reproduction into six strategies, defined on the basis of five life-history characters. We provide an up-to-date summary of reproductive traits in dasyurid species and examine the evolution of these characters on a phylogeny for the family recently obtained from DNA sequence data. Our results suggest that reproductive evolution in modern dasyurids is characterized by a basal separation of subfamily lineages employing Strategy II (monoestrous females, restricted breeding season, 11 months to maturity; Dasyurinae) and Strategy V (polyoestrous females, extended breeding season, 8–11 months to maturity; Sminthopsinae). Strategies I (male die-off) and III (facultative polyoestry) appear to have arisen several times from Strategy II or V ancestors, and Strategy IV appears to have arisen within Sminthopsis from a Strategy V ancestor. Strategy VI (aseasonal breeding) has arisen independently in each of the four major dasyurid lineages (tribes), and is highly (but not perfectly) correlated with New Guinean endemism. This scenario is not strongly affected if reproductive characters are optimized on an alternative phylogeny more consistent with morphology-based opinions on species relationships. When evaluated in light of current habitat associations and geographic distributions, the reproductive data suggest that the Miocene diversification of modern dasyurids may have been correlated with the invasion of dry forest or woodland habitats.     

Population and reproductive structure in the endangered and highly endemic freshwater crab Aegla concepcionensis (Decapoda:Pleocyemata:Aeglidae) from Chile

Population and reproductive information of highly endemic species allow us to understand their underlying conservation problems. Aegla concepcionensis is restricted to a small and intervened Chilean basin, and its conservation status has varied from extinct in nature to endangered. We characterized their life history measuring population, morphological and environmental variables during an annual cycle capturing individuals with a catch and release method based on electroshocking. Although the maximum water temperature was related to the recruitment, it can be physiologically risky for the remaining macroinvertebrate community. The relationship between abundance and narrow pH variations indicates a condition of unstable equilibrium given the environmental deterioration by deforestation. Sex ratio was predominantly male biased during copulatory activity, and sexually dimorphic body size distributions supported the hypothesis of greater natural selection in females and sexual selection in males. The period of ovigerous females was comparatively restricted, late and consistent with an efficient ecophysiological strategy of reproductive investment. Patterns of pubertal moult, onset of morphometric maturity, absence of morphological differentiation in both sexes suggested that A. concepcionensis tends to maximize reproductive performance favouring the recovery of their relict populations.     

Population structure of an endangered species living in contrasted habitats: Parnassia palustris (Saxifragaceae)

In endangered species, it is critical to analyse the level at which populations interact (i.e. dispersal) as well as the levels of inbreeding and local adaptation to set up conservation policies. These parameters were investigated in the endangered species Parnassia palustris living in contrasted habitats. We analysed population structure in 14 populations of northern France for isozymes, cpDNA markers and phenotypic traits related to fitness. Within population genetic diversity and inbreeding coefficients were not correlated to population size. Populations seem not to have undergone severe recent bottleneck. Conversely to pollen migration, seed migration seems limited at a regional scale, which could prevent colonization of new sites even if suitable habitats appear. Finally, the habitat type affects neither within-population genetic diversity nor genetic and phenotypic differentiation among populations. Thus, even if unnoticed local adaptation to habitats exists, it does not influence gene flow between populations.     

Reproductive biology of the Alaska skate Bathyraja parmifera,with comments on an intersexual individual

A total of 1357 specimens of Alaska skate Bathyraja parmifera were collected in the eastern Bering Sea by fisheries observers and during scientific groundfish surveys from 2003 to 2005. Male and female gonads were examined for maturity stage and seasonal reproductive timing. Based on seasonal reproductive data, including the occurrence of egg cases, ovum size, ovum number, shell‐gland width and gonado‐somatic index, this species appears to reproduce continually throughout the year. Potential effects of maternal size upon the size and number of mature oocytes were also investigated, with total length having a significant, although weak, influence on both. Morphology of a single intersexual individual encountered during the collection period is also described.     

Catalase activity in macro- and microorganisms as an indicator of biotic stress in coastal waters of the eastern Mediterranean Sea

In this study we examined the activity of catalase in the water column (mainly attributed to planktonic microorganisms) and the activity of catalase and superoxide dismutase (SOD), as well as lipid peroxidation in the midgut gland of the benthic bivalve Donax trunculus as possible indicators of biotic stress. The measurements were performed at stations situated at known contaminated and clean sites in the coastal waters and shores along the Israeli coast (eastern Mediterranean Sea). In the water column, we found that catalase activity was higher in polluted coastal waters than in nearby unpolluted or less-polluted stations. Moreover, there was diurnal periodicity in catalase activity rates which matched the diurnal changes in hydrogen peroxide levels in seawater. Consistent evidence of extracellular catalase activity was found in the seawater sampled. Catalase activity rates in the midgut gland of D. trunculus did not exhibit clear patterns with respect to site (polluted or clean) or season. However, SOD activity and lipid peroxidation measured in the same tissues were good indicators of organic pollution in the coastal waters examined and, among the three stations examined in Haifa Bay, Qiriat Haim was the most polluted.     

Investigations into the biology of the garfish, Belone belone (L.), in Swedish waters

Garfish, Belone belone (L.), were collected from commercial fishermen between May and September of 1987 from around the Swedish coast. Fish belonging to the year classes of 1983, 1984 and 1985 dominated the catch, with very few fish from the year classes of 1980, 1981 and 1982. Maturity stages and condition were investigated, and estimates of fecundity calculated; these ranged from 2193 to 10804 eggs per ripe female. Examination of gut contents showed fish, especially juvenile clupeids and gasterosteids, as well as isopods and amphipods, to be the most important components of their diet. Garfish populations from both the Baltic and the west coasts were parasitized by copepods of the genus Caligus . A study of meristic characteristics showed a significant difference between the number of vertebrae in fish from the Baltic and those captured on the west coast of Sweden.     

An experimental study of the reproductive biology and hybridization in the European and North American species of Equisetum

Sporophytc production was investigated in the eleven North American and European species of Equisetum by means of fertilization experiments on both intact and subcultured gametophytes. Comparison of intra- and inter-gametophytic selfing with intergametophytic crossing failed to reveal any evidence of recessive sporophytic lethals, leaky lethals or deleterious recessive genes. Fertilization in Equisetum depends solely on the availability of ripe archegonia. Despite the absence of detectable genetic load in Equisetum , intergametophytic mating is ensured by gametophyte dioecism in the wild. All populations tested were freely interfcrtile indicating a high degree oi genetic con-specihcity, even between North America and Europe. Low sporophyte frequencies in European E. scirpoides are attributed to defective spermatozoids. Polyembryony occurs. Cessation in gametophyte development is mediated by allelopathic compounds liberated from the young sporophytes.
Reciprocal crosses resulted in the synthesis of 12 hybrids (six in subgenus Equisetum and six in subgenus Hippochaete plus abortive zygotes in the cross E. ramosissimum female x E. scirpoides male), 11 of which had previously been reported in nature. No intersubgeneric hybrids were produced, indicating that both subgenera are natural groups only distantly related to one another. The putative wild combinations E. pratense x E. atvense and E. variegatum x E. scirpoides were not synthesized, but a new hybrid from the allopatric E. ramosissimum and E. laevigatum arose. Reciprocal crosses within the subgenus Hippochaete usually yielded equal frequencies of hybrids, but in the subgenus Equisetum the majority of successful crosses were unidirectional. All taxa oi Hippochaete are linked by hybrids whereas in subgenus Equisetum, E. pratense and E. sylvatkum form an isolated pair, Hybridization studies, and evidence from gametophyte morphology support the traditional sectional classification of Equisetum.     

Notes on the distribution and biology of the deep-sea crab Bathynectes maravigna (Brachyura: Portunidae) in the Mediterranean Sea

Data on the distribution and biology of the deep-sea portunid crab Bathynectes maravigna are reported for the Mediterranean Sea, based on several fisheries research surveys. Densities are low and, therefore, biological data are scarce. In the western Mediterranean, the species is much commoner in Alborán Sea than in the Catalano-Balearic Sea. Occurrences are also scarce in the southern Adriatic and northwestern Thyrrenian Sea, as well as in the Ionian Sea. The Alborán Sea and the seas surrounding the southern Italian peninsula are the areas where densities are the highest. The occurrence depth range was found to be 245–786 m, but most of the occurrences took place deeper than 500 m. Sizes ranged between 9 and 51 mm carapace length in males and between 12 and 51 mm in females. Ovigerous females have been only reported in October–December and March–May. Eighty three percent of both males and females are right-handed. Sexual dimorphism was present in cheliped length with males having longer chelae than females. The species appears to be much commoner in those areas where Atlantic influence is the highest.     

Life History Studies on the Genus Trillium (Liliaceae) III. Reproductive Biology of Six Sessile-flowered Species Occurring in the Southeastern United States with Special Reference to Vegetative Reproduction

Abstract Life history characteristics, e.g., stage class structures of natural populations and associated reproductive characteristics, were studied for six sessile-flowered, diploid Trillium (Liliaceae) species that are restricted to the Coastal Plain region of the southeastern United States.
These sessile-flowered species reproduce primarily by vegetative propagation. Leaf area measurements were used to categorize stage class distributions of natural populations. Populations propagating mainly by vegetative reproduction had non-sigmoidal, convex-shaped population structures with most plants being in the intermediate stage classes. Low numbers of individuals in smaller stage classes and an abundance of intermediate sized individuals are due to the fact that vegetative propagules are the primary method for maintenance of local populations.
Characteristics associated with sexual reproduction were also examined. Seed output averaged about 20 seeds per plant, except for T. lancifolium which produced 9.7 seeds on the average. Seed setting rates varied between 15.61–44.15% and mean seed weight varied from 4.89 to 10.75 mg. The dominance of vegetative versus sexual reproduction may be due to the fact that all six species occur in ecologically unstable flood plain habitats.     

Dynamics of core and occasional species in the marine plankton: tintinnid ciliates in the north-west Mediterranean Sea

Aim To assess short‐term variability in the community composition and community structure of tintinnid ciliates, herbivores of the microzooplankton. Location North‐west Mediterranean Sea. Methods We sampled on 18 dates over a 4‐week period in 2004 at an open‐water site. Species were classified as ‘core species’, found on every date, or ‘occasional species’, absent on one or more dates. Species abundance distributions of the entire community, and separately the core and occasional species, were compared with geometric, log‐series and log‐normal distributions. Core and occasional species were compared in terms of the shell or lorica oral diameter (LOD), analogous to gape size. Results We found 11 core and 49 occasional species. Diversity metrics were stable compared with shifts in abundances. Core species accounted for the majority of individuals in all samples. On each date, 9–22 occasional species, representing 10–15% of the population, were found. Species richness of the occasionals was positively related to population size. The identities of the occasional species found were unrelated to the time between sampling. The species abundance distribution of the occasional population was best fit by a log‐series distribution, while that of the core species was best fit by a log‐normal distribution. The species abundance distribution of the entire community was best fit by a log‐series distribution. Most of the occasional species had LODs distinct from that of a core species and occupied size classes left empty by the core population. However, the most abundant and frequent of the occasional species had a LOD similar to that of a core species. Main conclusions Among tintinnids, which are planktonic protists, occasional species have a species abundance distribution pattern distinct from that of core species. Occasional species appeared to be composed of two groups, one of relatively abundant species and similar to core species, and a second group of ephemeral species with morphologies distinct from core species. The existence of two categories of occasional or rare species may be common: (1) those similar to, and thus perhaps able to replace, dominant species in the absence of a change in the environment; and (2) those distinct from dominant species and requiring different conditions to prosper.     

The biology of the Red Sea migrant,Saurida undosquamis in the Mediterranean and comparison with the indigenous confamilial Synodus saurus (Teleostei: Synodontidae)

A study of the biology of Red Sea — Suez Canal migrant, the lizardfish Saurida undosquamis and the indigenous Synodus saurus was carried out in the Mediterranean coast of Israel. The spawning season of S. undosquamis lasts from March to December indicating a curtailment of the year-round spawning season of the source population in the Gulf of Oman. The spawning season of S. saurus is from February to August. The diameter of ripe oocytes of S. undosquamis is 500–600 μm. Females of S. undosquamis grow slightly faster than males and reach a larger size (340 mm TL versus 280 mm TL). Niche partitioning between the two lizardfishes is primarily on the basis of depth. The invador occupying deeper water. Both species are chiefly piscivorous but as a result of their depth distribution there is little diet overlap on the specific level.     

Spatial segregation in the reproductive activity of Neotropical fish species as an indicator of the migratory trait

This study focused on the distribution of fish with high reproductive activity along a basin, using a 430 km stretch of the Cuiabá River in Brazil as a model. The main objective of this study was to identify those fish that migrate long distances for reproduction, among all the basin species. Thus, a set of working criteria are proposed to classify species according to their reproductive behaviour (i.e., reproductive activity and distribution). Samplings were performed in the Cuiabá River basin, encompassing several environments (river, channels and lakes) during the reproductive periods (between October and February), from 2000 to 2004. Species occurrence (presence and absence – proxy of distribution) across the basin and index of reproductive activity values were used as criteria to identify the species that perform long-distance longitudinal migrations for reproduction. The study confirmed the classification of long-distance longitudinal migration species; nonetheless, some species were not classified as described in the literature. The proposed sequential criteria have proven to be effective in the classification of long-distance longitudinal migrations species and certainly contribute to filling some existing knowledge gaps of reproductive traits. This classification is of fundamental importance in planning new dam projects, in decision making and in the development of management and conservation actions for the ichthyofauna.     

Population genetic structure and levels of inbreeding depression in the Mediterranean island endemic Cyclamen creticum (Primulaceae)

The variation and evolution of reproductive traits in island plants have much attention from conservation and evolutionary biologists. However, plants on islands in the Mediterranean region have very little attention. In the present study, we examine the floral biology and mating system of Cyclamen creticum , a diploid perennial herb endemic to Crete and Karpathos. Our purpose is to quantify (1) variation and covariation of floral traits related to the mating system, (2) the ability of the species to self in the absence of pollinators and its relative performance on selfing and outcrossing and (3) generic diversity within and among populations. Pollen/ovule ratios were indicative of a xenogamous species. A controlled pollination experiment showed that the species is self-compatible but is unable to set seed, in the absence of pollinators, probably due to stigma-anther separation. A multiplicative estimate of inbreeding depression based on fruit maturation, seed number and percentage seed germination gave δ= 0.38 Population genetic diversity was high, 54.76% polymorphic loci, a mean of 1.78 alleles per locus and a mean observed heterozygosity of 0.053. F -statistics nevertheless indicated high inbreeding rates (mean F ^is= 0.748) in natural populations, and low levels of population differentiation (mean F^is= 0.168). C. creticum thus appears to have a mixed-mating system with high levels of (pollinator) mediated inbreeding (either by facilitated selfing, geitonogamy or biparental inbreeding) in natural populations.