scholarly journals Peer Review #3 of "Coastal fish assemblages and predation pressure in northern-central Chilean Lessonia trabeculata kelp forests and barren grounds (v0.1)"

2019 ◽  
Keyword(s):  
Peer Review ◽  
Fish Assemblages ◽  
Predation Pressure ◽  
Kelp Forests ◽  
Coastal Fish ◽  
Lessonia Trabeculata ◽  
Barren Grounds

scholarly journals Coastal fish assemblages and predation pressure in northern-central Chilean Lessonia trabeculata kelp forests and barren grounds

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6964 ◽  
Author(s):  
Nicolás Riquelme-Pérez ◽  
Catalina A. Musrri ◽  
Wolfgang B. Stotz ◽  
Osvaldo Cerda ◽  
Oscar Pino-Olivares ◽  
...  
Keyword(s):  
Fish Assemblages ◽  
Sea Urchins ◽  
Kelp Forest ◽  
Predation Pressure ◽  
Predatory Fish ◽  
The Black Sea ◽  
Kelp Forests ◽  
Fishing Activity ◽  
Rocky Habitats ◽  
Barren Grounds

Kelp forests are declining in many parts of the globe, which can lead to the spreading of barren grounds. Increased abundances of grazers, mainly due to reduction of their predators, are among the causes of this development. Here, we compared the species richness (SR), frequency of occurrence (FO), and maximum abundance (MaxN) of predatory fish and their predation pressure between kelp forest and barren ground habitats of northern-central Chile. Sampling was done using baited underwater cameras with vertical and horizontal orientation. Two prey organisms were used as tethered baits, the black sea urchin Tetrapygus niger and the porcelanid crab Petrolisthes laevigatus. SR did not show major differences between habitats, while FO and MaxN were higher on barren grounds in vertical videos, with no major differences between habitats in horizontal videos. Predation pressure did not differ between habitats, but after 24 h consumption of porcelanid crabs was significantly higher than that of sea urchins. Scartichthys viridis/gigas was the main predator, accounting for 82% of the observed predation events on Petrolisthes laevigatus. Most of these attacks occurred on barren grounds. Scartichthys viridis/gigas was the only fish observed attacking (but not consuming) tethered sea urchins. High abundances of opportunistic predators (Scartichthys viridis/gigas) are probably related to low abundances of large predatory fishes. These results suggest that intense fishing activity on large predators, and their resulting low abundances, could result in low predation pressure on sea urchins, thereby contributing to the increase of T. niger abundances in subtidal rocky habitats.

scholarly journals What are the main local drivers determining richness and fishery yields in tropical coastal fish assemblages?

2018 ◽  
Vol 35 ◽  
pp. 1-12
Author(s):  
Cynthia Diniz Souza ◽  
Vandick S. Batista ◽  
Nidia Noemi Fabré
Keyword(s):  
Wind Speed ◽  
Rainy Season ◽  
Fish Assemblages ◽  
Principal Component ◽  
Dry Season ◽  
Community Diversity ◽  
Tropical Species ◽  
Coastal Fish ◽  
Wide Range ◽  
Diversity Profiles

Seasonal ecological effects caused by temperature and photoperiod are typically considered minimal in the tropics. Nevertheless, annual climate cycles may still influence the distribution and abundance of tropical species. Here, we investigate whether seasonal patterns of precipitation and wind speed influence the structure of coastal fish assemblages and fishing yields in northeast Brazil. Research trips were conducted during the rainy and dry seasons using commercial boats and gear to sample the fish community. Diversity was analyzed using abundance Whittaker curves, diversity profiles and the Shannon index. Principal Component Analysis (PCA) was used to analyze associations between the abundance of species and various environmental variables related to seasonality. A total of 2,373 fish were collected, representing 73 species from 34 families – 20 of which were classified as both frequent and abundant. Species richness was greater and more equitable during the rainy season than the dry season – driven by changes in the precipitation rather than to wind speed. Species diversity profiles were slightly greater during the rainy season than the dry season, but this difference was not statistically significant. Using PCA was identified three groups of species: the first associated with wind speed, the second with precipitation, and the third with a wide range of sampling environments. This latter group was the largest and most ecologically heterogeneous. We conclude that tropical coastal fish assemblages are largely influenced by local variables, and seasonally mediated by annual changes related to precipitation intensity and wind speed, which in turn influences fishery yields.

scholarly journals Brook trout (Salvelinus fontinalis) extinction in small boreal lakes revealed by ephippia pigmentation: a preliminary analysis

2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Alexandre Bérubé Tellier ◽  
Paul E. Drevnick ◽  
Andrea Bertolo
Keyword(s):  
Brook Trout ◽  
Fish Assemblages ◽  
Salvelinus Fontinalis ◽  
Sediment Cores ◽  
Experimental Studies ◽  
Cost Effective ◽  
Fish Predation ◽  
Boreal Lakes ◽  
Predation Pressure ◽  
Trout Population

<p>Ephippium pigmentation is a plastic trait which can be related to a trade-off between visual predation pressure and better protection of cladoceran eggs against different types of stress. Experimental studies showed that planktivorous fish exert a greater predation pressure on individuals carrying darker ephippia, but little is known about the variation of ephippium pigmentation along gradients of fish predation pressure in natural conditions. For this study, our experimental design included four small boreal lakes with known fish assemblages. Two of the lakes have viable brook trout (<em>Salvelinus fontinalis</em>) populations, whereas the other two lakes experienced brook trout extinctions during the 20<sup>th</sup> century. Cladoceran ephippia were extracted from sediment cores at layers corresponding to the documented post- extinction phase (1990's) and from an older layer (1950's) for which the brook trout population status is not known precisely. Our first objective was to determine whether brook trout extinction has a direct effect on both ephippium pigmentation and size. Our second objective was to give a preliminary assessment of the status of brook trout populations in the 1950's by comparing the variation in ephippia traits measured from this layer to those measured in the 1990's, for which the extinction patterns are well known. Cost-effective image analysis was used to assess variation in pigmentation levels in ephippia. This approach provided a proxy for the amount of melanin invested in each ephippium analysed. Our study clearly shows that ephippium pigmentation may represent a better indicator of the presence of fish predators than ephippium size, a trait that showed a less clear pattern of variation between lakes with and without fish. For the 1990's period, ephippia from fishless lakes were darker and showed a slight tendency to be larger than ephippia from lakes with brook trout. However, no clear differences in either ephippium size or pigmentation were observed between the 1990's and 1950's layers within each lake. This suggests that brook trout extinction already occurred before the 1950’s, or that brook trout population abundance was already extremely low before and after the 1990’s. Our preliminary study shows that ephippium pigmentation can be used as a tool to quickly assess present and past predation levels on zooplankton when only sediment samples are available.</p>

Distribution and abundance of Rhynchocinetes typus (Crustacea: Decapoda), in different benthic community structures in northern Chile

2003 ◽  
Vol 83 (1) ◽  
pp. 143-150 ◽  
Author(s):  
Luis M. Caillaux ◽  
Wolfgang B. Stotz
Keyword(s):  
Benthic Community ◽  
Subtidal Zone ◽  
Suspension Feeding ◽  
North Central ◽  
The North ◽  
Lessonia Trabeculata ◽  
Different Types ◽  
Community Types ◽  
Shrimp Abundance ◽  
Barren Grounds

An evaluation was carried out on the distribution and abundance of the rock shrimp Rhynchocinetes typus in the inshore subtidal zone on the north-central coast of Chile. A number of different benthic community types occur in the region which have different degrees of spatial complexity provided by the primary substratum and by the biotic communities colonizing the substratum. Shrimp abundance was estimated in five different community types including shallow and deep ‘barren grounds’, low encrusting communities, erect suspension feeding associations, and kelp beds of Lessonia trabeculata. The abundance of shrimp was determined on three different types of primary substratum (stones, boulders, rock mass) within each community. Rhynchocinetes typus occurred in all the communities studied, showing the highest abundance on the deep barren grounds and lowest abundance on the shallow barren grounds. The shrimp was found to prefer the stony areas, as these offered the greatest degree of refuge. The abundance of predators was not significantly different among the different communities. However, a decline of abundance of predators was apparent over the deep barren grounds.

scholarly journals Seasonal patterns and diets of wild fish assemblages associated with Mediterranean coastal fish farms

2008 ◽  
Vol 65 (7) ◽  
pp. 1153-1160 ◽  
Author(s):  
Damian Fernandez-Jover ◽  
Pablo Sanchez-Jerez ◽  
Just Tomás Bayle-Sempere ◽  
Carlos Valle ◽  
Tim Dempster
Keyword(s):  
Fish Assemblages ◽  
Abundant Species ◽  
Stomach Content Analysis ◽  
Wild Fish ◽  
Seasonal Patterns ◽  
Fish Farms ◽  
Coastal Fish ◽  
Fish Stocks ◽  
Floating Structures ◽  
Cage Fish

Abstract Fernandez-Jover, D., Sanchez-Jerez, P., Bayle-Sempere, J. T., Valle, C., and Dempster, T. 2008. Seasonal patterns and diets of wild fish assemblages associated with Mediterranean coastal fish farms. – ICES Journal of Marine Science, 65: 1153–1160. Fish are attracted to floating structures, including coastal cage fish farms, sometimes in dense aggregations. To understand better the influence of aquaculture on wild fish stocks, we carried out seasonal visual censuses around three southwestern Mediterranean farms over 2 years to assess the temporal patterns of the aggregated fish assemblage. In addition, we analysed the diet of the five most abundant species. Aggregations around all farms were large throughout the year, although species composition and abundance differed among farms and seasons. Fish farms are attractive habitats for certain species of wild fish in specific seasons. Adult fish of reproductive size dominated the assemblages, and stomach content analysis revealed that 66–89% of fish of the five most abundant taxa had consumed food pellets lost from the cages. We estimated that wild fish consume up to 10% of the pellets used at farms, indicating that food is a key attractant. Regional monitoring of farm-associated wild fish assemblages could aid management of the interaction of aquaculture and wild fish resources, because changes in feeding behaviour may have consequences for fish populations and local fisheries.

Alien and native fish in gill nets at Rhodes, eastern Mediterranean (2014–2015)

2017 ◽  
Vol 97 (3) ◽  
pp. 635-642 ◽  
Author(s):  
Maria Corsini-Foka ◽  
Stefanos Mastis ◽  
Gerasimos Kondylatos ◽  
Ioannis E. Batjakas
Keyword(s):  
Native Species ◽  
Fish Assemblages ◽  
Eastern Mediterranean ◽  
Aegean Sea ◽  
Total Biomass ◽  
Coastal Fish ◽  
Gill Net ◽  
Fish Catch ◽  
Siganus Rivulatus ◽  
Catch Composition

Fish catch composition in 21 gill net samplings performed between 2014 and 2015 at Rhodes Island (Aegean Sea, Greece) was analysed, with the aim to contribute in filling scattered information on coastal fish assemblages in a Mediterranean region heavily impacted by biological invasions. A total biomass of 183 kg was collected comprising 1070 fish individuals, distributed along 43 native and six Lessepsian migrant species. The alien Siganus luridus prevailed in terms of frequency of occurrence, followed by the native Sparisoma cretense, which exhibited the higher abundance and biomass, followed by S. luridus, Scorpaena scrofa and Siganus rivulatus. Ratios between alien and native species as well as between their abundance and biomass are discussed.

Spatiotemporal variation in the structure of reef fish and macroalgal assemblages in a north-east Atlantic kelp forest ecosystem: implications for the management of temperate rocky reefs

2018 ◽  
Vol 69 (4) ◽  
pp. 525 ◽  
Author(s):  
Pablo Pita ◽  
Diana Fernández-Márquez ◽  
Juan Freire
Keyword(s):  
Reef Fish ◽  
Fish Assemblages ◽  
Kelp Forest ◽  
Habitat Destruction ◽  
Kelp Forests ◽  
Rocky Reef ◽  
Laminaria Hyperborea ◽  
East Atlantic ◽  
North East ◽  
Rocky Reefs

Temperate rocky reefs and kelp forest ecosystems have been severely affected by overfishing, pollution and habitat destruction, and climate change is a major driver of kelp decline in many regions. Although necessary for management, ecological interactions between kelp and fish remain largely unknown in the north-east Atlantic. In the present study, underwater visual censuses (UVC) and univariate and multivariate multiple regression models were used to analyse the spatiotemporal variations in the abundance and habitat use of the rocky reef fish and macroalgae assemblages of Galicia (north-west Spain). The underwater seascape was dominated by large rocks and kelp forests of Laminaria hyperborea, L. ochroleuca and Saccorhiza polyschides. Fish assemblages were ruled by gadids, labrids and sparids. The most frequent fish species were Labrus bergylta (counted in 90% of UVC) and Pollachius pollachius (in 100% of UVC), whereas the most abundant were Boops boops (mean±s.d., 556.4±39.7 individuals ha–1) and L. bergylta (432.10±440.05 individuals ha–1). Fish and macroalgal assemblages showed different spatial preferences and responded strongly to seasonality, wave exposure and depth. To a lesser degree, fish and macroalgal assemblages showed preferences for habitat structure. Moreover, because the findings of the present study indicate that L. bergylta is a good indicator species of the health of rocky reef and kelp forests ecosystems, monitoring of this fish can be helpful for management and conservation actions.

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