The Nile perch, Lates niloticus (L.), stock in Lake Victoria may be showing signs of overfishing as the average size of fish decreased rapidly in 2007 when the stock biomass fell by 50%. Fishers have increasingly abandoned large-meshed gillnets in favour of small hooks on long lines. This has allowed prey species (Rastrineobola argentea [Pellegrin] and haplochromines) to increase, shifting the…
Spawning is a key but often fragile event in the life cycles of fish populations. Nevertheless, it has been relatively little studied for lithophilic lacustrine species requiring hard spawning substrates, such as gravels or stones, largely devoid of fine sediments. Twelve demonstrated or putative spawning grounds of Arctic charr (Salvelinus alpinus) in shallow and deep areas of the north and s…
1. Bycatch of non-target species in commercial fishing nets can have adverse impacts on their populations. Freshwater turtle populations are particularly susceptible to increases in adult mortality, and freshwater turtles are among the most threatened vertebrates. 2. As a case study, the population-level impacts of bycatch mortality on freshwater turtles were evaluated in Lake Opinicon, Ontari…
A total of 30 microsatellite markers were isolated from miiuy croaker, Miichthys miiuy, and characterized. Of these, 24 were polymorphic with an average of 4.33 alleles per locus (range: 2–8). The observed (Ho) and expected (He) heterozygosities ranged from 0.0667 to 1.0000 (mean: 0.6361) and 0.3828 to 0.8139 (mean: 0.6443), respectively. The mean polymorphism information content (PIC) value …
We explored potential negative effects of exotic brown trout (Salmo trutta) on native sculpin (Cottus sp.) on the Logan River, Utah, USA by (i) examining factors most strongly correlated with sculpin abundance (e.g., abiotic conditions or piscivory?), (ii) contrasting the extent of brown trout predation on sculpin with that by native cutthroat trout (Oncorhynchus clarkii utah) and (iii) estimat…
We evaluate the current status of the global marine fisheries using the frameworks of conflict, food security and vulnerability. Existing trends suggest that there is likely to be greater food insecurity and fisheries conflicts due to issues such as: declining fishery resources; a North–South divide in investment; changing consumption patterns; increasing reliance on fishery resources for coa…
Oogenesis in fishes follows a universal plan; yet, due to differences in the synchrony and rate of egg development, spawning frequency varies from daily to once in a lifetime. Some species spawn and feed in separate areas, during different seasons, by storing energy and drawing on it later for reproduction (i.e. capital breeding). Other species spawn using energy acquired locally, throughout a …
The salmonid orthomyxovirus infectious salmon anaemia virus (ISAV) causes disease of varying severity in farmed Atlantic salmon, Salmo salar L. Field observations suggest that host factors, the environment and differences between ISAV strains attribute to the large variation in disease progression. Variation in host mortality and dissemination of ISAV isolates with high and low virulence (ba…
Sardinella aurita is the most abundant small pelagic fish in the Senegalese–Mauritanian region. The success of its reproduction crucially depends on the local circulation as this determines whether larvae reach coastal nursery areas favorable to their survival or are dispersed into the open ocean. As a first step towards evaluating sardinella vulnerability to climate-driven hydrodynamical cha…
Marine coastal habitats are important as nurseries for numerous fish species (Biagi et al., 1998; Felix-Hackradt et al., 2013). A large body of literature dealing with community composition, spatial and temporal variability, substrate use and mortality of fish recruits in inshore marine habitats is available for the western Mediterranean Sea (Garcia- Rubies and Macpherson, 1995; Macpherson et…
Stable isotope analysis has been used in a number of studies to understand the food habitats, trophic positions and migration of fishes (Hobson 1999; Post et al. 2000), based on the stepwise enrichment of d13C and d15N values from prey to predators (DeNiro & Epstein 1978, 1981). However, the use of stable isotope ratios for studying dietary shifts in fishes has often been hampered by the slow…
Macrobenthic faunal composition was studied at six different depth ranges (30–50, 51–75, 76–100, 101–150, 151–175 and >176 m) in five transects (off Karaikkal, Parangipettai, Cuddalore-SIPCOT, Cheyyur and Chennai) in the continental shelf of southeast coast of India. Eleven diverse taxa were found, comprising 113 species of polychaetes, 14 species of bivalves, 10 species of amphipods …
The aim of this survey was to study the cover and the composition of macroepiphytic species on the leaves of Posidonia oceanica in the east of Tunisia. Surveys were conducted in December 2009 (winter period), March (spring period and August 2010 (summer period) in a fringing reef located in Chebba. At each sampling date, 15 adult leaves were randomly collected and divided into basal and apical …
Large-scale environmental impacts, such as those of climate change on fisheries, require policy and management action not only at the local level, but at regional, national and international levels. Fisheries biology and ecology, along with social, political and economic considerations, can influence policy design and implementation. Decision-support tools can integrate these sciences to disti…
The mechanisms through which brown-marbled grouper accomplishes resistance to infection, particularly against Vibrios, are not yet fully understood. In this study, brown-marbled grouper fingerlings were experimentally infected with Vibrio parahaemolyticus, to identify disease resistance grouper, and the serum proteome profiles were compared between resistant and susceptible candidates, via t…
A common observation is that egg size increases with maternal size within populations. Several hypotheses have been proposed to explain this phenomenon. Most recently, it was suggested that the optimal egg size depends on female size due to correlations between (i) breeding time and egg size selection and (ii) female size and breeding time, and as such, the positive egg size–maternal size re…
A 60-d feeding trial was conducted to investigate the effect of dietary maize starch on growth performance, feed utilization, and apparent digestibility coefficient (ADC) and key hepatic enzyme activities regulating glycolytic and gluconeogenic metabolic pathways of juvenile obscure puffer, Takifugu obscurus (Abe) (initial body weight = 7.9±0.2 g). Five isonitrogenous and isolipidic diets cont…
The effect of four different light regimes on growth was studied in lenok, Brachymystax lenok. Fish with average weights of 5.5 g were subjected to four different photoperiods (0L:24D, 6L:18D, 12L:12D and 24L:0D) for 35 days. The specific growth rate (SGR) of lenok in 24-h darkness had a significantly higher SGR than those in the continuous light regime (P < 0.05); however, there was no signifi…
Whether territoriality regulates population size depends on the flexibility of territory size, but few studies have quantified territory size over a broad range of densities. While juvenile salmonids in streams exhibit densitydependent mortality and emigration, consistent with space limitation, there has been relatively little study of how territory size and individual growth rate change over a…
Aquaculture is one of the fast-growing industries in the past decades. The fast expansion of aquaculture largely relies on the introduction and use of non-native species. This forms a paradox: some species significantly contribute to the fast expansion of aquaculture, while negative effects associated with unregulated introduction and irresponsible use of non-native species are increasing in nu…
This article examines national and regional dependence on fisheries in mainland China. In 2010, the fishing industry in mainland China contributed 1.5% to annual national GDP and represented 9.3% of value added by all primary production sectors. The annual value of fishery exports accounted for about 30% of the national food export value. It provided an average of more than 40 kg yr1 of animal…
In this study, the complete foxl2 complementary (c)DNA sequence was isolated by simple modular-architecture research tool (SMART)er rapid amplification of cDNA ends (RACE). Two year-old female spotted scat, Scatophagus argus, were reared at different temperatures (23, 26 and 29∘ C) for 6 weeks, or fed with different concentrations of dietary fish oil (0, 2 or 6%) for 8 weeks. Ovarian developm…
In the present study we investigated the biogeography of macrozooplankton and fish biomass in the Bay of Biscay. In this region, we defined six different landscapes based on the hydrogeographical characteristics observed in spring 2009. We then related landscape’s characteristics and environmental parameters such as light attenuation depth and chlorophyll-a with macrozooplankton and fish aco…
Abstract The Columbia River Basin (Basin) is located in the Pacific Northwest, United States. The 370 hydroelectric dams in the Basin provide the Pacific Northwest with many services including hydropower generation, flood control, agricultural irrigation and navigation. The basin also provides habitat for a variety of anadromous and resident fishes and wildlife species. Balancing the energy dem…
1. Asian topmouth gudgeon Pseudorasbora parva has been recognized as a highly invasive cyprinid fish species in Europe that may present risk to native fish communities. 2. The present study aimed to investigate whether a native piscivorous fish, pike Esox lucius, is able to reduce the establishment success and invasiveness of topmouth gudgeon in shallow ponds. A large-scale, replicated whole-p…
Size-at-entry regulations in fisheries cause major disruption to aquatic ecosystems, including truncation of age- and size-structures, destabilization of fish stocks, directional selection on phenotypic traits and a by-catch of unwanted species and sizes. Here, we use simple dynamic models of size-spectra to examine an alternative, socalled balanced harvesting. Balanced harvesting helps in reta…
Larval growth and hatching days of lanternfishes Diogenichthys laternatus and Myctophum nitidulum (Myctophidae) collected in September 2012 in nearshore waters (
Palaemon serratus juveniles (0.18±0.06 g) were exposed to different concentrations of ammonia in a series of acute toxicity tests by the static renewal method at four salinity levels (10, 20, 30, and 40 ppt) at 29 C and at a pH of 8.0. Oxygen consumption rate (OCR) was also measured. The mortality rate increased with increasing concentrations of ammonia and longer exposure times. High salini…
The Murray–Darling Basin (MDB) covers 1.1 million km2, involves six legislative jurisdictions, a myriad of different agencies and illustrates the many complexities of managing fishes, people and water. Its rivers provide water for agriculture, are highly regulated and generally in poor health. Water allocation reform is underway to improve ecological condition but provision of water for envi…
This study focused on the comparison of growth and mortality of Lion’s Paw scallops Nodipecten subnodosus from Gulf of California and Pacific populations and their reciprocal transplants, cultured in suspended module and bottom culture in Baja California Sur, Mexico. Environmental parameters were monitored to determine site-specific differences and were correlated with scallops’ populati…
Natural populations of unisexual species occur among fish, amphibians and reptiles through normal reproductive strategies such as gynogenesis and hybridogenesis (Cimino, 1971; Dawley, 1989; Goddard and Schultz, 1993). Such unisexual populations have been reported in about 90 biotypes, which are commonly known as polyploids (Dawley, 1989; Vrijenhoek et al., 1989; Vasil’ev et al., 2005; Janko e…
Diel drift patterns of larvae of the endangered cyprinid Gnathopogon caerelescens in an inlet of the Ibanaiko Lagoon, connected to Lake Biwa in Japan, were assessed in April 2012. Peak occurrence of yolk-sac larvae was within a few hours after dark. Drift of newly hatched larvae is considered to be an important biological mechanism that ensures larval dispersal and recruitment from the inlets…
Existing biological data on whiting Merlangius merlangus, cod Gadus morhua and haddock Melanogrammus aeglefinus from a long-term international survey were analysed to address sexual size dimorphism (SSD) and its effect on their ecology and management. Results show that SSD, with larger females of the same age as males, is a result of higher growth rates in females. A direct consequence of SSD i…
Annual fishes, which inhabit temporary pools with extremely limited habitat complexity and niche availability, display remarkable sexual dimorphism, rapid growth, and enormous investment into reproduction, all traits associated with high energy requirement. This study tests three hypotheses for two syntopic annual fishes (Austrolebias minuano and Cynopoecilus fulgens) found in six wetlands of …
Betanodavirus infection was diagnosed in larvae of farm-raised tilapia Oreochromis niloticus (L.), in central Thailand. Extensive vacuolar degeneration and neuronal necrosis were observed in histological sections with positive immunohistochemical staining for betanodavirus. Molecular phylogenetic analysis was performed based on the nucleotide sequences (1333 bases) of the capsid protein gene…
Flavobacterium psychrophilum is the causative agent of bacterial cold-water disease (BCWD) and causes severe loss of aquaculture production of ayu sweetfish Plecoglossus altivelis altivelis (Temminck & Schlegel, 1846) in Japan (Wakabayashi, Toyama & Iida 1994). The characteristics of BCWD in ayu are different from those of BCWD in salmonid fishes. BCWD in ayu generally occurs when water tempera…
Marine exit timing of sockeye salmon Oncorhynchus nerka populations on the Haida Gwaii Archipelago, British Columbia, Canada, is described, with specific focus on Copper Creek. Marine exit in Copper Creek occurs>130 days prior to spawning, one of the longest adult freshwater residence periods recorded for any O. nerka population. Copper Creek presents an easy upstream migration, with mild wate…
China has a long history of aquaculture, and it contributes the largest aquaculture production worldwide. Aside from expanding aquaculture area and maximizing unit yield, introducing new potential species is greatly encouraged. Icefish (Salangidae) from Taihu Lake have been introduced into other lakes and reservoirs throughout the country since 1979. Neosalanx tangkahkeii was introduced into th…
The immune response in rainbow trout fry against Flavobacterium psychrophilum was elucidated using an immersion-based challenge with or without prior exposure to hydrogen peroxide (H2O2). Samples were taken from the head kidney 4, 48, 125 and 192 h after immersion, and the regulation of several genes was examined. Bacterial load was assessed based on the presence of 16S rRNA and correlated wit…
Localized hypoxic habitats were created in Delta Marsh, Manitoba, Canada to determine the potential of regions of moderate hypoxia to act as refuges for forage fishes from piscine predators. Minnow traps and giving-up density (GUD) plates (plexiglas plates covered with trout crumble and fine gravel) were used to assess habitat use and perceived habitat quality for forage fishes, respectively…
A previous study documented a correlation between Atlantic Cod (Gadus morhua) recruitment in the Gulf of Maine and an annual index of the north component of May winds. This correlation was supported by modeling studies that indicated strong recruitment of Gulf of Maine Atlantic Cod results from high retention of spring-spawned larvae in years when winds were predominately out of the north, whic…
During ichthyological research and teaching activities in the Cape Verde Archipelago, the authors noticed that the readily available inventories of its sea fishes underrepresented the mesopelagic species, contrary to an older Spanish list, which regrettably remained widely unknown. These inventories were compared, revised, combined and commented on, plus a multitude of individual descriptions,…
1. Predators exert a strong selective force on the ecosystems in which they exist, thereby altering the structure of ecological communities and leading to the evolution of prey defences. However, how interspecific differences in defence ability affect habitat partitioning amongst competing prey species remains unresolved. 2. We examined how prey defences affect species distribution in a natu…
1. Information on the life-history traits of threatened fishes can inform their conservation as they can indicate resilience to environmental change and vulnerability to extirpation and extinction. Garra ghorensis, a small (2 years. Variability in length at age was apparent within sites, suggesting protracted spawning. Females were significantly larger than males. 4. Growth rates and lifespans…
The objective of this study was to establish the relationships between bioelectrical impedance analysis (BIA) measures (resistance and reactance) and temperature and to determine if corrections improve BIA models for brook trout Salvelinus fontinalis when used over a wide range of temperatures. Both resistance and reactance significantly decreased as temperature increased. Application of temper…
Feeding guilds and spatial, seasonal and ontogenetic changes in the diets of 24 fish species in a tropical bay in Southeastern Brazil were examined. The hypotheses tested were that groups of species form specific trophic guilds and that the feeding partitioning differs along the niche dimensions. Five trophic guilds (Polychaeta, Copepoda, Teleostei, Teleostei/Crustacea and Polychaeta/ Crustacea…
Population abundance, distribution and habitat preference of the Mediterranean sympatric seahorses Hippocampus guttulatus and Hippocampus hippocampus were investigated in a semi-enclosed sea system (Apulian coast, Ionian Sea). A total of 242 individuals of seahorses were sighted in the 11 transects surveyed in summer 2011. Hippocampus guttulatus (n = 225) were 14 times more abundant than H. hip…
Predation risk is high for the many small coral reef fishes, requiring successful sheltering or other predator defence mechanisms. Coral-dwelling gobies of the genus Gobiodon live in close association with scleractinian corals of the genus Acropora. Earlier studies indicated that the low movement frequency of adult fishes and the development of skin toxins (crinotoxicity) are predation avoidanc…
The majority of the global inland fisheries catch is obtained in developing countries. However, there are severe constraints in collection of information on inland fisheries leading to doubts over the reliability of the available information at the global and regional scales. A major constraint of data collection is the dispersed characteristics of inland fisheries, which cannot be covered by t…
1. Despite their geographic proximity, the Gulf of Ambracia and the Inner Ionian Sea Archipelago are remarkably different in terms of environmental features, human activities, and dolphin species composition and densities. 2. Interviews of small-scale professional fishermen (n=100) showed that younger generations do not see any future in fisheries and that the traditionally-oriented fishing c…