scholarly journals The mechanisms of intertidal fish coexistence: a model

2014 ◽  
Author(s):  
Chris J Barrett ◽  
Magnus L Johnson ◽  
Susan L Hull
Keyword(s):  
Gadus Morhua ◽  
Common Species ◽  
Melanogrammus Aeglefinus ◽  
Fish Diversity ◽  
Important Species ◽  
European Otter ◽  
Commercially Important ◽  
Near Threatened ◽  
Prey Items ◽  
Intertidal Fishes

Research into the ecology of intertidal fishes of the U.K. appears to be lacking, reportedly due to the mobility and cryptic nature of the more common species. However, some intertidal fishes contribute to the diets of commercially important species such as cod (Gadus morhua), haddock (Melanogrammus aeglefinus) and near-threatened European otter (Lutra lutra). The current study contains the first comprehensive research into the ecology of intertidal fishes from the English, Yorkshire coast and Welsh, Anglesey coast, identifying and addressing the mechanisms which allow for their coexistence. Seven mechanisms were identified which promote interspecific fish coexistence. It was found that coexistence can occur when: (I) fish diversity on a shore is low, thus minimising high degrees of co-occurrence within pools, (II) co-occurrence on shores (at tidal height level) is minimal and when fishes do co-occur, they are of similar sizes thus reducing size-dominated hierarchies, (III) the significant variables which predict fish presences differ, (IV) there is an abundance of shelter/protection readily available, which reduces the competition to access such features, (V) morphology is such, that for the majority of the year, it is more profitable for the piscivorous fishes to predate on food items other than fish, (VI) competition for prey items is reduced, when variability of resources is high, and (VII) there is a difference in the most targeted prey items between fish species, despite some overlap in targeted prey items.

scholarly journals The mechanisms of intertidal fish coexistence: a model

2014 ◽  
Author(s):  
Chris J Barrett ◽  
Magnus L Johnson ◽  
Susan L Hull
Keyword(s):  
Gadus Morhua ◽  
Common Species ◽  
Melanogrammus Aeglefinus ◽  
Fish Diversity ◽  
Important Species ◽  
European Otter ◽  
Commercially Important ◽  
Near Threatened ◽  
Prey Items ◽  
Intertidal Fishes

Research into the ecology of intertidal fishes of the U.K. appears to be lacking, reportedly due to the mobility and cryptic nature of the more common species. However, some intertidal fishes contribute to the diets of commercially important species such as cod (Gadus morhua), haddock (Melanogrammus aeglefinus) and near-threatened European otter (Lutra lutra). The current study contains the first comprehensive research into the ecology of intertidal fishes from the English, Yorkshire coast and Welsh, Anglesey coast, identifying and addressing the mechanisms which allow for their coexistence. Seven mechanisms were identified which promote interspecific fish coexistence. It was found that coexistence can occur when: (I) fish diversity on a shore is low, thus minimising high degrees of co-occurrence within pools, (II) co-occurrence on shores (at tidal height level) is minimal and when fishes do co-occur, they are of similar sizes thus reducing size-dominated hierarchies, (III) the significant variables which predict fish presences differ, (IV) there is an abundance of shelter/protection readily available, which reduces the competition to access such features, (V) morphology is such, that for the majority of the year, it is more profitable for the piscivorous fishes to predate on food items other than fish, (VI) competition for prey items is reduced, when variability of resources is high, and (VII) there is a difference in the most targeted prey items between fish species, despite some overlap in targeted prey items.

scholarly journals In vitrodigestibility of different prey species of minke whales (Balaenoptera acutorostrata)

1993 ◽  
Vol 70 (2) ◽  
pp. 485-489 ◽  
Author(s):  
Erling S. Nordøy ◽  
Wenche Sørmo ◽  
Arnoldus Schytte Blix
Keyword(s):  
Gadus Morhua ◽  
Prey Species ◽  
Initial Step ◽  
Common Species ◽  
Clupea Harengus ◽  
Melanogrammus Aeglefinus ◽  
Balaenoptera Acutorostrata ◽  
Minke Whales ◽  
Digestion Technique

Information on diet composition, daily energy expenditure, energy storage and the utilization of energy in the prey are important factors when evaluating the food consumption of minke whales (Balaenoptera acutorostrata) during their summer stay in northern waters. The purpose of the present study was in this context to obtain information on the digestible energy (DE) of different prey selected by minke whales. Anin vitrothree-stage digestion technique, simulating the different compartments of the digestive system, has been developed. The initial step simulated the anaerobic microbial fermentation of substrate in the fortestomach. The next stage included the addition of pepsin (EC3.4.23.1)–HCI, simulating ventricle enzymic decomposition, and finally, in the third step, fresh extract from duodenal contents was used to simulate enzymic intestinal degradation of the remaining components of the food. The inoculum was normally obtained from animals which had recently eaten the prey to be tested. In such tests we obtained a dry matter disappearance (DMD) and a DE for herring (Clupea harengus) of 80·4 (SD 5·0)% (n18) and 92·1 (SD 3·7) % (n16) respectively, and a DMD of krill (Thysanoessasp.) of 83·4 (SD 4·9)% (n6). The DMD of krill was reduced to 73·8 (SD 7·3)% (n8) while the DE was 70·6 (SD 10·4) % (n7) when inoculum from whales which had recently eaten cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) was used. These results indicate a high digestibility of the most common species of prey in these animals, and also that the whales have little difficulty in changing from one prey species to another.

scholarly journals The vertical separation of fish in the aft end of a demersal trawl

2009 ◽  
Vol 66 (4) ◽  
pp. 772-777 ◽  
Author(s):  
Ludvig Ahm Krag ◽  
René Holst ◽  
Niels Madsen
Keyword(s):  
Vertical Distribution ◽  
Gadus Morhua ◽  
Melanogrammus Aeglefinus ◽  
Multinomial Model ◽  
Vertical Separation ◽  
Commercially Important ◽  
Merlangius Merlangus ◽  
The Vertical Distribution ◽  
Haddock Melanogrammus Aeglefinus ◽  
Important Fish

Abstract Krag, L. A., Holst, R., and Madsen, N. 2009. The vertical separation of fish in the aft end of a demersal trawl. – ICES Journal of Marine Science, 66: 772–777. Two multi-compartment separator frames were used to study the vertical separation of some commercially important fish species in the aft end of a trawl, with the aim of separating cod (Gadus morhua) from other species. A non-linear multinomial model with random effects was used to analyse the data and to compare the performance of the two frames. The vertical distribution of cod in the aft end of the trawl was close to uniform, whereas haddock (Melanogrammus aeglefinus), whiting (Merlangius merlangus), plaice (Pleuronectes platessa), and lemon sole (Microstomus kitt) showed more uneven distributions. The use of guiding bars in the separator frame significantly (p < 0.05) increased the catch of cod, plaice, and lemon sole in the upper compartment. The vertical separation of cod was density-dependent; high densities of fish resulted in a more uniform distribution of cod. The species separations found differ from those reported from the studies of species separation in the region of the trawl mouth.

scholarly journals Thermal biology and swimming performance of Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus)

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7784 ◽  
Author(s):  
Tommy Norin ◽  
Paula Canada ◽  
Jason A. Bailey ◽  
A. Kurt Gamperl
Keyword(s):  
Gadus Morhua ◽  
Metabolic Response ◽  
Atlantic Cod ◽  
Swimming Performance ◽  
Melanogrammus Aeglefinus ◽  
Thermal Biology ◽  
Oxygen Transport Capacity ◽  
Thermal Maximum ◽  
Commercially Important ◽  
Better Than

Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) are two commercially important marine fishes impacted by both overfishing and climate change. Increasing ocean temperatures are affecting the physiology of these species and causing changes in distribution, growth, and maturity. While the physiology of cod has been well investigated, that of haddock has received very little attention. Here, we measured the metabolic response to increasing temperatures, as well as the critical thermal maximum (CTmax), of cod acclimated to 8 and 12 °C and haddock acclimated to 12 °C. We also compared the swimming performance (critical swimming speed, Ucrit) of cod and haddock at 12 °C, as well as the Ucrit of 12 °C-acclimated cod acutely exposed to a higher-than-optimal temperature (16 °C). The CTmax for cod was 21.4 and 23.0 °C for 8- and 12 °C-acclimated fish, respectively, whereas that for the 12 °C-acclimated haddock was 23.9 °C. These values were all significantly different and show that haddock are more tolerant of high temperatures. The aerobic maximum metabolic rate (MMR) of swimming cod remained high at 16 °C, suggesting that maximum oxygen transport capacity was not limited at a temperature above optimal in this species. However, signs of impaired swimming (struggling) were becoming evident at 16 °C. Haddock were found to reach a higher Ucrit than cod at 12 °C (3.02 vs. 2.62 body lengths s−1, respectively), and at a lower MMR. Taken together, these results suggest that haddock perform better than cod in warmer conditions, and that haddock are the superior swimmer amongst the two species.

scholarly journals The use of species-specific TaqMan probes for identifying early stage gadoid eggs following formaldehyde fixation

2008 ◽  
Vol 65 (9) ◽  
pp. 1573-1577 ◽  
Author(s):  
Freya Goodsir ◽  
Michael J. Armstrong ◽  
Peter R. Witthames ◽  
David L. Maxwell ◽  
Clive J. Fox
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Early Stage ◽  
Melanogrammus Aeglefinus ◽  
Fish Eggs ◽  
Important Species ◽  
Taqman Probes ◽  
Positive Rate ◽  
Identification Technique ◽  
Species Specific

Abstract Goodsir, F., Armstrong, M. J., Witthames, P. R., Maxwell, D. L., and Fox, C. J. 2008. The use of species-specific TaqMan probes for identifying early stage gadoid eggs following formaldehyde fixation. – ICES Journal of Marine Science, 65: 1573–1577. Surveys of fish eggs are increasingly being used to monitor the spawning areas and stock status of commercially important species such as Atlantic cod (Gadus morhua), but early stage cod eggs are visually indistinguishable from those of several other common co-occurring species, including haddock (Melanogrammus aeglefinus) and whiting (Merlangius merlangus). In recent surveys in the Irish and North Seas, a molecular identification technique (TaqMan multiplex real-time polymerase chain-reaction) assay has been used to overcome this problem. The method needs high-quality DNA, so the current protocol requires that individual “cod-like” eggs are “presorted” from plankton hauls on board ship and immediately preserved in ethanol. This increases seagoing staff costs, can be a difficult process at sea, and means that plankton sampling cannot be undertaken from non-specialized vessels such as fishing boats. Successful application of TaqMan probes to DNA from eggs preserved in formalin would overcome these problems, but previous attempts have resulted in poor success. In this study, batches of hatchery-sourced cod, haddock, and whiting eggs were fixed in 4% buffered formalin for up to 3 weeks, then transferred to a formaldehyde-free solution for 1, 2, or 3 months. After these periods they were assessed visually for fixation quality and analysed using species-specific TaqMan probes. Eggs, which had been fixed for up to 3 weeks in formalin, were identified successfully, although the positive rate (84–96%) was slightly lower than samples preserved throughout in ethanol (92–99%). There was no increase in the percentage of eggs misidentified comparing formalin-fixed and ethanol-preserved material. These results suggest that TaqMan probes can be applied successfully to fish eggs fixed in 4% buffered formalin for up to 3 weeks.

scholarly journals Fish Diversity and Conservation Perspectives of Gandak River, India

Our Nature ◽  
2013 ◽  
Vol 11 (1) ◽  
pp. 76-84 ◽  
Author(s):  
P. K. Srivastava
Keyword(s):  
Distribution Pattern ◽  
Fish Species ◽  
Lower Risk ◽  
Uttar Pradesh ◽  
Assemblage Structure ◽  
Fish Diversity ◽  
Threat Status ◽  
Commercially Important ◽  
Gandak River ◽  
Near Threatened

Study of 10 km stretch of Gandak River in Uttar Pradesh revealed the ichthyofaunal diversity, assemblage structure, distribution pattern, threat status, ornamental and commercially important fishes. In all 54 fish species were recorded of many commercially important fishes. Among these species 45% belong to lower risk near threatened (LRnt), 26% vulnerable (VU), 11% lower risk least concern (LRlc), 11% not evaluated (NE) and 7% endangered (EN) category. Cyprinidae 33% were most important followed by Bagridae (11%), Channidae (9%), Tetradontidae (5%). DOI: http://dx.doi.org/10.3126/on.v11i1.8246 Our Nature Vol.11(1) 2013: 76-84

scholarly journals Status of fish diversity in Surha Taal, a natural lake in the floodplains of river Ganga, in Ballia District, Uttar Pradesh, India

2020 ◽  
Vol 67 (3) ◽  
Author(s):  
A. K. Pathak ◽  
U. K. Sarkar ◽  
Rehana Abidi
Keyword(s):  
Species Diversity ◽  
Fish Species ◽  
Conservation Status ◽  
Fish Diversity ◽  
Important Species ◽  
Post Monsoon ◽  
Natural Lake ◽  
Wallago Attu ◽  
River Ganga ◽  
Near Threatened

The study presents the status of fish diversity, abundance and habitat structure of Surha Lake, which is a perennial and natural lake fed by the river Ganga. The study was conducted between 2011 to 2013 covering pre and post-monsoon seasons. In total, 4,852 individual fish specimens were collected representing 66 fish species belonging to 23 families. The species diversity comprised 65 species in pre-monsoon and 60 species in post-monsoon season (p<0.05). The highest species diversity was recorded for the family Cyprinidae (22), followed by Bagridae (7). An assessment of conservation status of 66 fish species as per IUCN Red List 2019 criteria listed 6 species under near threatened (NT), 54 under least concern (LC) and two species under vulnerable (VU) category. The study reports several commercially important species under near threatened (Chitala chitala, Labeo pangusia, Ompok bimaculatus, Ompok pabda, , Ailia coila and Bagarius bagarius), which makes Surha Taal an important natural lake from fishery management point of view. The study also prioritised different habitat types important for different species. The slow water in the mid-channel areas of the lake were categorised as important habitats for near threatened and vulnerable fish species like C. chitala, B. bagarius and Wallago attu, which can be prioritised for population level management.

Parasites as biological tags in marine fisheries research: European Atlantic waters

Parasitology ◽  
2014 ◽  
Vol 142 (1) ◽  
pp. 54-67 ◽  
Author(s):  
K. MACKENZIE ◽  
W. HEMMINGSEN
Keyword(s):  
Marine Mammals ◽  
Gadus Morhua ◽  
Clupea Harengus ◽  
Melanogrammus Aeglefinus ◽  
Ecological Group ◽  
The North ◽  
Recent Developments ◽  
Host Parasite ◽  
Mediterranean And Black Seas ◽  
Biological Tags

SUMMARYStudies of the use of parasites as biological tags for stock identification and to follow migrations of marine fish, mammals and invertebrates in European Atlantic waters are critically reviewed and evaluated. The region covered includes the North, Baltic, Barents and White Seas plus Icelandic waters, but excludes the Mediterranean and Black Seas. Each fish species or ecological group of species is treated separately. More parasite tag studies have been carried out on Atlantic herring Clupea harengus than on any other species, while cod Gadus morhua have also been the subject of many studies. Other species that have been the subjects of more than one study are: blue whiting Micromesistius poutassou, whiting Merlangius merlangus, haddock Melanogrammus aeglefinus, Norway pout Trisopterus esmarkii, horse mackerel Trachurus trachurus and mackerel Scomber scombrus. Other species are dealt with under the general headings redfishes, flatfish, tunas, anadromous fish, elasmobranchs, marine mammals and invertebrates. A final section highlights how parasites can be, and have been, misused as biological tags, and how this can be avoided. It also reviews recent developments in methodology and parasite genetics, considers the potential effects of climate change on the distributions of both hosts and parasites, and suggests host-parasite systems that should reward further research.

scholarly journals Induced sterility in fish and its potential and challenges for aquaculture and germ cell transplantation technology: a review

Biologia ◽  
2016 ◽  
Vol 71 (8) ◽  
Author(s):  
Amin Golpour ◽  
Mohammad Abdul Momin Siddique ◽  
Diógenes Henrique Siqueira-Silva ◽  
Martin Pšenička
Keyword(s):  
Germ Cell ◽  
Cell Transplantation ◽  
Large Scale ◽  
Hormonal Treatment ◽  
Important Species ◽  
Genetic Ablation ◽  
Germ Cell Transplantation ◽  
Commercially Important ◽  
Alternative Approaches ◽  
Hormone Signalling

AbstractInterest in reproductively sterile fish in aquaculture has prompted research into their production. Several methods are available for inducing sterility and optimizing its application in the global fishery industry. Sterilization can potentially be accomplished through irradiation, surgery, or chemical and hormonal treatment. Alternative approaches include triploidization, hybridization, and generation of new lines via advanced biotechnological techniques. Triploids of many commercially important species have been studied extensively and have been produced on a large scale for many years. Novel approaches, including disruption of gonadotropin releasing hormone signalling and genetic ablation of germ cells, have been developed that are effective in producing infertile fish but have the disadvantage of not being 100% reliable or are impractical for large-scale aquaculture. We review currently used technologies and recent advances in induction of sterility in fish, especially those intended for use in germ cell transplantation. Knowledge of the implications of these approaches remains incomplete, imposing considerable limitations.

Do changes in reef habitats influence relative predation risk on the juvenile Australasian spiny lobster, Jasus edwardsii (Hutton, 1875)?

Crustaceana ◽  
2015 ◽  
Vol 88 (7-8) ◽  
pp. 839-856 ◽  
Author(s):  
J. Hesse ◽  
J. A. Stanley ◽  
A. G. Jeffs
Keyword(s):  
Predation Risk ◽  
Spatial Scales ◽  
Spiny Lobster ◽  
Habitat Type ◽  
Small Spatial Scale ◽  
Important Species ◽  
Early Juvenile ◽  
Risk Of Predation ◽  
Jasus Edwardsii ◽  
Commercially Important

Kelp habitats are in decline in many temperate coastal regions of the world due to climate change and expansion of populations of grazing urchins. The loss of kelp habitat may influence the vulnerability to predators of the juveniles of commercially important species. In this study relative predation rates for kelp versus barren reef habitat were measured for early juvenile Australasian spiny lobster, Jasus edwardsii (Hutton, 1875), on the northeastern coast of New Zealand using tethering methods. Variation in assemblages of predators over small spatial scales appeared to be more important for determining the relative predation of lobsters, regardless of habitat type. Therefore, the assessment of relative predation risk to early juvenile lobsters between kelp and barren habitats will require more extensive sampling at a small spatial scale, as well as a specific focus on sampling during crepuscular and nocturnal periods when these lobsters are most at risk of predation.

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