scholarly journals Performance of a baited underwater video system vs. the underwater visual census technique in assessing the structure of fish assemblages in a Mediterranean marine protected area

2021 ◽  
Vol 22 (3) ◽  
pp. 480
Author(s):  
GABRIELLA LA MANNA ◽  
IVAN GUALA ◽  
DANIELE GRECH ◽  
FRANCESCO PERRETTI ◽  
FABIO RONCHETTI ◽  
...  

Accurate, rapid and cost-effective fish assemblage monitoring is fundamental for marine protected area (MPA) management as a pivotal tool to verify whether and to what extent MPA conservation objectives have been achieved and to redefine these objectives in the framework of an adaptive management. Recently, there has been a sharp increase in the number of video-based methods to study fish fauna, such as baited remote underwater video (BRUV) systems, that, depending on the objectives of the monitoring, can provide complementary or additional data to the more commonly used underwater visual census (UVC). Even though BRUV systems have been widely used in a wide range of geographic contexts and habitats, their use in the Mediterranean basin is still sporadic and the evaluation of the efficiency of BRUV systems and whether they can be used to complement other techniques needs investigation. Thus, the objective of this study was to assess the performance of a BRUV system in a Mediterranean MPA and to evaluate its effectiveness in assessing the structure of fish assemblages (abundance and species richness) by comparing estimates with those obtained by the UVC technique. The fish fauna were monitored by BRUV and UVC in the Capo Caccia – Isola Piana Marine Protected Area (Sardinia, Italy), in July and October-November 2020, at four sampling sites and two areas, hundreds of meters apart, for each site. Overall, 46 taxa and a total of 3620 individuals were observed by BRUV, while 36 taxa and a total of 2995 individuals were observed by UVC. The species first observed in front of the camera’s field of view and able to reach the maximum abundance were the planktivores (Chromis chromis and Oblada melanura) followed by several carnivorous species belonging to the families Labridae, Serranidae and Sparidae, and lastly two carnivores (Mullus surmuletus and Mugilidae spp.) and some high-level predators (Dentex dentex, Seriola dumerili, Sphyraena viridensis, Dicentrarchus labrax). The maximum species richness and abundance were reached between 39 and 50 min. The cumulative species richness increased until around 30 min. Species richness was higher during the BRUV compared to the UVC monitoring. The consistency in findings between BRUV and UVC and a better performance of BRUV in detecting some species (mainly high-level predators), supports BRUV as an additional technique for describing and quantifying species richness and abundance also in the Mediterranean Sea. Based on the results of this study, the advantages/disadvantages, shortcomings, suggestions and resources needed for the two techniques are outlined.

2021 ◽  
Vol 5 (1) ◽  
pp. 214
Author(s):  
Rizki Dimas Permana ◽  
Sunarto Sunarto ◽  
Syawalludin Alisyahbana Harahap ◽  
Indah Riyantini ◽  
Yuwanda Ilham

The coral reef ecosystem has been continuously degraded in various parts of Indonesia, including the Anambas Islands. This research aimed to discover the content of Potassium Cyanide (KCN) accumulated on corals and the effect on indicator fishes abundance in the Anambas Islands. This research was conducted at 25 observation stations in the Anambas Islands National Marine Protected Area. The potassium cyanide (KCN) content was tested with the principle of titration and distillation. The coral samples used ranged from 10-20 g diluted in 100-200 ml distilled water. The method used to determine the abundance of indicator fish was underwater visual census or UVC, which recorded fish in every station. This research recorded 307 fish individuals from 14 species of the Chaetodontidae family. Potassium Cyanide's content on corals was high ranging from 0,009-0,032 mg/L with an average 0,0205 mg/L. We concluded that there was a negative correlation between the content of Potassium Cyanide  (KCN) on corals and indicator fishes abundance, which means the higher the Potassium Cyanide content (KCN) is on corals, the lower the indicator fishes abundance will point out.


2008 ◽  
Vol 66 (1) ◽  
pp. 180-187 ◽  
Author(s):  
Catherine Seytre ◽  
Patrice Francour

Abstract Seytre, C., and Francour, P. 2009. The Cap Roux MPA (Saint-Raphaël, French Mediterranean): changes in fish assemblages within four years of protection. – ICES Journal of Marine Science, 66: 180–187. In recent decades, marine reserves have been established to protect ecosystem structure and biological diversity, or as management tools to combat the overexploitation of fish stocks. The Cap Roux Marine Protected Area (MPA) was established by professional fishers in December 2003, in the French Mediterranean between Cannes and Saint-Raphaël. It was implemented to enhance target fish stocks for local fisheries. The objective of this 3-year study was to investigate the initial responses of fish assemblages, using complementary methods: experimental net fishing performed by a professional fisher and underwater visual census. Within 3 years, this study detected early changes in the fish assemblages. The methods also detected an increase in abundance and diversity of fish, but also a decrease of seasonal fluctuations of the assemblage structure, which was characterized by winter values close to summer values in the protected zone but not outside of the MPA. These results helped clarify the dynamic by which fish assemblages respond to fishing prohibition in a newly created protected area.


2014 ◽  
Vol 2 (3) ◽  
Author(s):  
Abner A Bucol

An underwater visual census (UVC) conducted to assess the biophysical conditions of the two marine protected areas (Antulang Marine Protected Area and Andulay Marine Protected Area) in Siaton, Negros Oriental revealed slow recovery from severe damage resulting from Typhoon Sendong in December 2011, suggestive of “coral-algal phase-shift”. Live hard coral (LHC) cover was consistently poor in the survey sites (2.25±0.78 % in Antulang Marine Protected Area; 1.25±0.50 % in the Control Site; and 3.33±0.17 % in Andulay Marine Protected Area) following destruction by the typhoon and colonization of algae (between 37-53%), dominated by Bornetella oligospora. Mean total fish biomass (including fusiliers and schooling juvenile Caranx sexfasciatus) was highest in Antulang Marine Protected Area at 70.60±28.07 kg/500m2 (equivalent to 141.21±56.14 tonne/km2) while lowest in Andulay Marine Protected Area at 9.83±4.32 kg/500m2. Mean total fish density was highest in Antulang Marine Protected Area at 597.0±114.7 fish/500m2 followed by the Control Site with 361.7±159.0 fish/500 m2, while Andulay Marine Protected Area had 200.7±31.6 fish/500m2. Fish species composition was slightly altered, i.e. decline in coral-dependent species such as damselfishes. Keywords: coral reef, macroalgae, phase-shift, resilience, recovery, typhoon


2018 ◽  
Vol 82 (2) ◽  
pp. 95 ◽  
Author(s):  
Ana Gordoa ◽  
Jordi Boada ◽  
Antoni García-Rubies ◽  
Oscar Sagué

Characterizing fish communities must be a priority to safeguard resources and determine critical changes. Here, species richness and the spatial and temporal evolution in the structure of fish assemblages were analysed based on photos taken in underwater free-diving contests. A total of 29 contests held from 2008 to 2015 at four different locations along the northeastern Spanish coast, including a marine protected area were analysed. Contests reward the number of species per participant and photographic quality. Species image frequency from each tournament were standardized to catch image rate. A total of 88 taxa were recorded, including 32 cryptobenthic species, the highest number recorded in the Mediterranean littoral system so far. Cluster analyses yielded four major groups. Catch image rates in the marine protected area were significantly higher for seven species of high commercial interest and for two big labrids of recreational interest, including an endangered species (Labrus viridis). Overall, the study showed that photographic free-diving contest data are a potential tool for determining species richness in littoral systems since contest rules promote competition between participants to obtain maximum fish diversity. We believe that this type of cost-effective data can be applied worldwide as a complementary way of monitoring littoral fish assemblage.


PLoS ONE ◽  
2014 ◽  
Vol 9 (1) ◽  
pp. e84344 ◽  
Author(s):  
Delphine Mallet ◽  
Laurent Wantiez ◽  
Soazig Lemouellic ◽  
Laurent Vigliola ◽  
Dominique Pelletier

2020 ◽  
Vol 167 (2) ◽  
Author(s):  
Christina Skinner ◽  
Aileen C. Mill ◽  
Steven P. Newman ◽  
S. Nadia Alsagoff ◽  
Nicholas V. C. Polunin

AbstractPredators on coral reefs play an important ecological role structuring reef fish communities and are important fishery targets. It is thought that reef predator assemblages increase in density and diversity from inner lagoonal to outer edge reefs. Oceanic atolls may differ though, as nutrients are available throughout. Reef predator populations are declining, but there is little known about how their distributions may vary across oceanic atolls. Using a combination of underwater visual census and baited remote underwater video, this study aimed to compare reef predator populations between inner and outer reefs of North Malé Atoll (Maldives) and determine which reef metrics may drive any differences in assemblage structure. We found that predator assemblages were significantly different between inner and outer atoll. Body sizes of several predator families were consistently larger in the outer atoll, however, abundance, biomass and species richness were similar between outer edge reefs and inner lagoonal reefs suggesting atoll lagoons may be undervalued habitats. Depth and complexity were consistently important predictors of the predator assemblage. Inner atoll lagoonal habitat is equally as important for reef predator assemblages as outer reef slopes, although the dominant species differ. This study provides important information on reef predator populations in the Maldives, where detailed assessments of the reef predator assemblage are lacking but the reef fishery is thriving and annual catch will continue to increase.


2015 ◽  
Author(s):  
Jula Selmani ◽  
Stela Ruci ◽  
Denada Kasemi ◽  
Sajmir Beqiraj ◽  
Lefter Kashta

The seagrass Posidonia oceanica meadows are scarcely studied in the Albanian coast. Data presented in this work have been collected during an assessment of benthic communities of Sazani Island, Albania, in May 2013. The P. oceanica meadow has a limited distribution around this island, covering a relatively small area on its eastern coast. Although this meadow seems to be under degradation, it is still a good shelter for high species number and high abundance of benthic macroinvertebrates. The highest species richness and abundance has been recorded for sponges, hydrozoans, gastropods, bivalves, polychaetes, echinoderms, bryozoans and ascidians. The sciaphilic and photophilic communities were clearly evident, associated respectively to the P. oceanica rhizomes and leaves. Referring to the species richness and abundance, a rapid assessment of ecological and environmental state of benthic macroinvertebrate community has been done. Other parameters used for the assessment of the state of P. oceanica meadow have also been recorded, and possible reasons for the degradation of the meadow have been highlighted. These assessments of the benthic macroinvertebrate community and the state of seagrass meadow are also important within the framework of monitoring, conservation and management of the only Marine Protected Area of Albania, where Sazani Island is a core area.


2017 ◽  
Vol 18 (1) ◽  
pp. 11 ◽  
Author(s):  
G. LA MESA ◽  
E. SALVATI ◽  
S. AGNESI ◽  
L. TUNESI

The fish assemblages of the coastal area of the promontory of Cape Milazzo (Italy, Central Mediterranean), which has been recently designated by the Italian Law to become a national marine protected area (MPA), were characterized by visual censuses carried out over different habitats (rocky algal reef, Posidonia oceanica meadow and soft bottom) and depth ranges (0-3, 4-7, 12-16 and 24-30 m) to identify areas of major concern for the MPA zoning. The study area was divided into 6 sectors to assess spatial-related differences in the assemblage parameters, such as species composition and richness, and the size structure of species of recreational (e.g. SCUBA diving) interest. Fifty-eight taxa (56 species and 2 genera) and 20 families of fishes were totally recorded. Species composition was significantly affected by habitat and depth, whereas no significant changes were detected among sectors. Conversely, species richness and total density of fish showed no significant differences among sectors, habitat types and depth ranges. The majority of species of recreational value was recorded only off the northwestern part of the promontory. The implementation of fishing ban in such an area, characterized by the presence of a rocky bank, would contribute to the recovery of populations of some emblematic species (e.g. groupers and other large predator) and to the enhancement of environmentally sustainable activities such as scuba diving. Throughout the investigated area and, especially, in the eastern and southwestern coasts of the promontory, several species were almost exclusively represented by small and medium sized individuals, a likely consequence of an intense fishing pressure.


2018 ◽  
Author(s):  
Joel Williams ◽  
Alan Jordan ◽  
David Harasti ◽  
Peter Davies ◽  
Tim Ingleton

AbstractThe spatial distribution of a species assemblage is often determined by habitat and climate. In the marine environment, depth can become an important factor as degrading light leads to changes in the biological habitat structure. To date, much of the focus of ecological fish research has been based on reefs in less than 40 m with little research on the ecological role of mesophotic reefs. We deployed baited remote underwater stereo video systems (stereo-BRUVS) on temperate reefs in two depth categories: shallow (20-40m) and mesophotic (80-120m), off Port Stephens, Australia. Sites were selected using data collected by swath acoustic sounder to ensure stereo-BRUVS were deployed on reef. The sounder also provided rugosity, slope and relief data for each stereo-BRUVS deployment. Multivariate analysis indicates that there are significant differences in the fish assemblages between shallow and mesophotic reefs, primarily driven by Ophthalmolepis lineolatus and Notolabrus gymnogenis only occurring on shallow reefs and schooling species of fish that were unique to each depth category: Atypichthys strigatus on shallow reefs and Centroberyx affinis on mesophotic reefs. While shallow reefs had a greater species richness and abundance of fish when compared to mesophotic reefs, mesophotic reefs hosted the same species richness of fishery targeted species. Chrysophrys auratus (pink snapper) and Nemodactylus douglassii (grey morwong) are two highly targeted species in this region. While C. auratus was numerically more abundant on shallow reefs, mesophotic reefs provide habitat for larger fish. In comparison, N. douglassii were evenly distributed across all sites sampled. Generalized linear models revealed that depth and habitat type provided the most parsimonious model for predicting the distribution of C. auratus, while habitat type alone best predicted the distribution of N. douglassii. These results demonstrate the importance of mesophotic reefs to fishery targeted species and therefore have implications for informing the management of these fishery resources on shelf rocky reefs.


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