scholarly journals Conservation of coastal stingrays: seasonal abundance and population structure of the short-tailed stingray Dasyatis brevicaudata at a Marine Protected Area

2012 ◽  
Vol 69 (8) ◽  
pp. 1427-1435 ◽  
Author(s):  
A. Le Port ◽  
S. Lavery ◽  
J. C. Montgomery

Abstract Le Port, A., Lavery, S., and Montgomery, J. C. 2012. Conservation of coastal stingrays: seasonal abundance and population structure of the short-tailed stingray Dasyatis brevicaudata at a Marine Protected Area. – ICES Journal of Marine Science, 69: . Elasmobranch (shark, ray, and skate) populations around the world are in decline, and effective conservation measures are urgently needed. Marine Protected Areas (MPA) placed in locations important for key life-history stages may form part of an effective conservation strategy. In this context, we examined the seasonal abundance and population structure of the short-tailed stingray (Dasyatis brevicaudata) at an offshore MPA in northeastern New Zealand, and the reported use of this location as a mating ground. Diver surveys were conducted from 2004 to 2007 at the Poor Knights Islands Marine Reserve (PKIMR). During this time, we observed: (i) a substantial increase in adult and subadult numbers, particularly females during the suggested breeding season, and a corresponding increase in females bearing fresh mating scars; and (ii) large numbers of smaller (probably immature) D. brevicaudata individuals of both sexes from spring to autumn. These results suggest that the PKIMR acts as both a mating aggregation location and a nursery for this species. We suggest that for coastal stingrays such as D. brevicaudata, small MPAs may be effective at protecting key life-history stages, but that as movements outside of reserve boundaries also occur, additional management tools may also be necessary.

2011 ◽  
Vol 54 (2) ◽  
pp. 137-147 ◽  
Author(s):  
Marisa I. Batista ◽  
Filipa Baeta ◽  
Maria J. Costa ◽  
Henrique N. Cabral

2015 ◽  
Vol 66 (5) ◽  
pp. 399 ◽  
Author(s):  
Peter M. Yates ◽  
Michelle R. Heupel ◽  
Andrew J. Tobin ◽  
Stephen K. Moore ◽  
Colin A. Simpfendorfer

Effective conservation and management of shark populations is complicated by our limited understanding of their spatial ecology. For example, there are scarce data on diversity in community structure and nursery function across broader geographic scales (e.g. across multiple inshore systems) and the implications of this diversity for shark populations. Accordingly, fishery-independent surveys were undertaken to investigate shark communities along ~400km of the tropical eastern coast of Australia (18.1–20.6°S, 146.0–148.8°E). A variety of shark species were encountered, with 19 species of Carcharhiniformes contributing 99.2% of the total shark catch. Of the 1806 sharks captured, 567 were immature, including 336 young-of-the-year individuals. Immature sharks from 18 species were present; however, interspecific variation in the proportions of life-history stages was apparent. Multivariate analyses identified significant spatial heterogeneity in immature-shark communities. Results also highlighted the importance of tropical coastal habitats for numerous shark species, and indicated community-wide spatial structuring of sharks on the basis of body size rather than life-history stage. In addition to building on traditional shark-nursery paradigms, these results demonstrated that data on nursery function from restricted areas may not accurately portray patterns occurring over broader geographic scales, and this diversity may provide population-level benefits for sharks.


2009 ◽  
Vol 67 (2) ◽  
pp. 191-203 ◽  
Author(s):  
Aitor Forcada ◽  
Carlos Valle ◽  
José L. Sánchez-Lizaso ◽  
Just T. Bayle-Sempere ◽  
Fabio Corsi

Abstract Forcada, A., Valle, C., Sánchez-Lizaso, J. L., Bayle-Sempere, J. T., and Corsi, F. 2010. Structure and spatio-temporal dynamics of artisanal fisheries around a Mediterranean marine protected area. – ICES Journal of Marine Science, 67: 191–203. Marine protected areas (MPAs) have been proposed and established throughout the world, but few studies have adequately assessed the spatial adaptations of fishers to the limitations imposed by their placement. The main objectives of this work were to identify and describe the characteristics of the artisanal fisheries around Tabarca Marine Reserve (western Mediterranean Sea) and to define their activity in space and time. Data were collected through questionnaires to fishers and onboard sampling. The artisanal fisheries were complex owing to the multispecific nature of the landings, the variety of gears involved, and their marked seasonality. All boats of the three harbours around the MPA were assessed, for a total of 32 boats. The fishers exploit 18 fishing grounds with eight gear types, for a total of 17 métiers. Mullus trammelnet, Sepia trammelnet, and sparid longline are the most frequently used métiers. The main factors determining the spatial distribution of the fishing effort are proximity to home harbour, habitat heterogeneity, and closeness to the MPA. Total fishing effort appeared slightly concentrated around the MPA, but each métier showed different patterns of effort distribution. Although the sparid gillnet and the sparid longline concentrated along MPA boundaries, the Sepia trammelnet and the Mullus trammelnet did not.


2018 ◽  
Vol 10 (7) ◽  
pp. 1154 ◽  
Author(s):  
Marco Palma ◽  
Monica Casado ◽  
Ubaldo Pantaleo ◽  
Gaia Pavoni ◽  
Daniela Pica ◽  
...  

Animal forests promote marine habitats morphological complexity and functioning. The red gorgonian, Paramuricea clavata, is a key structuring species of the Mediterranean coralligenous habitat and an indicator species of climate effects on habitat functioning. P. clavata metrics such as population structure, morphology and biomass inform on the overall health of coralligenous habitats, but the estimation of these metrics is time and cost consuming, and often requires destructive sampling. As a consequence, the implementation of long-term and wide-area monitoring programmes is limited. This study proposes a novel and transferable Structure from Motion (SfM) based method for the estimation of gorgonian population structure (i.e., maximal height, density, abundance), morphometries (i.e., maximal width, fan surface) and biomass (i.e., coenenchymal Dry Weight, Ash Free Dried Weight). The method includes the estimation of a novel metric (3D canopy surface) describing the gorgonian forest as a mosaic of planes generated by fitting multiple 5 cm × 5 cm facets to a SfM generated point cloud. The performance of the method is assessed for two different cameras (GoPro Hero4 and Sony NEX7). Results showed that for highly dense populations (17 colonies/m2), the SfM-method had lower accuracies in estimating the gorgonians density for both cameras (60% to 89%) than for medium to low density populations (14 and 7 colonies/m2) (71% to 100%). Results for the validation of the method showed that the correlation between ground truth and SfM estimates for maximal height, maximal width and fan surface were between R2 = 0.63 and R2 = 0.9, and R2 = 0.99 for coenenchymal surface estimation. The methodological approach was used to estimate the biomass of the gorgonian population within the study area and across the coralligenous habitat between −25 to −40 m depth in the Portofino Marine Protected Area. For that purpose, the coenenchymal surface of sampled colonies was obtained and used for the calculations. Results showed biomass values of dry weight and ash free dry weight of 220 g and 32 g for the studied area and to 365 kg and 55 Kg for the coralligenous habitat in the Marine Protected Area. This study highlighted the feasibility of the methodology for the quantification of P. clavata metrics as well as the potential of the SfM-method to improve current predictions of the status of the coralligenous habitat in the Mediterranean sea and overall management of threatened ecosystems.


2008 ◽  
Vol 66 (1) ◽  
pp. 50-55 ◽  
Author(s):  
Olivier Chateau ◽  
Laurent Wantiez

Abstract Chateau, O., and Wantiez, L. 2009. Movement patterns of four coral reef fish species in a fragmented habitat in New Caledonia: implications for the design of marine protected area networks. – ICES Journal of Marine Science, 66: 50–55. Acoustic telemetry was used to examine the patterns of fish movements between a marine reserve and two unprotected reefs separated by large areas of lagoon soft bottoms (900–2000 m) in the South Lagoon Marine Park of New Caledonia. Four commercial fish species (Epinephelus maculatus, Plectropomus leopardus, Chlorurus microrhinos, and Scarus ghobban) were studied for 17 months (45 fish). Nine fish (20%) were detected on reefs other than the reef onto which they were released. Four patterns of inter-reef movement were identified during the survey, including home range relocations, movements larger than the scale of the study, many inter-reef movements within the study area, and punctual excursions outside the daily home range. The information gathered in this study demonstrates the ability of the fish to carry out medium-scale movements in a fragmented habitat. Consequently, the effectiveness of the reserve to protect the entire population is probably limited for these species. Because all the identified patterns implied at least one movement across the reserve boundaries, our results support the hypothesis that the Larégnère Marine Reserve, part of the South Lagoon Marine Park, could benefit the adjacent fished area through spillover.


2017 ◽  
Vol 98 (6) ◽  
pp. 1383-1389 ◽  
Author(s):  
Unai Markaida ◽  
Luis Flores ◽  
Evelyn Arias ◽  
Elba Mora

Octopus mimus is the main octopus targeted by the small-scale fishery in the Eastern Pacific. Commercial catches of octopus from the Reserva de Producción Faunística Marino-Costera Puntilla de Santa Elena (REMACOPSE) Marine Protected Area in Ecuador were sampled from July to December 2013 in order to describe the reproduction and population structure of this octopus. The 4171 sampled octopuses ranged from 56 to 250 mm in mantle length (ML) and 45 to 3178 g in body weight (BW). Mean octopus weight did not change monthly. Males were mostly mature while the majority of females were immature. Presence of some mature and a few spent females in all months sampled suggests that the population shows an extended spawning period. No spawning peak could be properly defined. Sex ratios did not significantly shift from the expected 1:1 in most samples. Females mature at a larger size (1234 g, BW; 165 mm, ML) than males (487 g BW; 114 mm ML). We recommend considering a minimum legal size of 1200 g BW. A year-long sampling programme for O. mimus should also be completed in order to detect any spawning peak.


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.


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