scholarly journals Nondestructive Monitoring of Soft Bottom Fish and Habitats Using a Standardized, Remote and Unbaited 360° Video Sampling Method

Fishes ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 50
Author(s):  
Delphine Mallet ◽  
Marion Olivry ◽  
Sophia Ighiouer ◽  
Michel Kulbicki ◽  
Laurent Wantiez

Lagoon soft-bottoms are key habitats within coral reef seascapes. Coral reef fish use these habitats as nurseries, feeding grounds and transit areas. At present, most soft-bottom sampling methods are destructive (trawling, longlining, hook and line). We developed a remote, unbaited 360° video sampling method (RUV360) to monitor fish species assemblages in soft bottoms. A low-cost, high-definition camera enclosed in a waterproof housing and fixed on a tripod was set on the sea floor in New Caledonia from a boat. Then, 534 videos were recorded to assess the efficiency of the RUV360. The technique was successful in sampling bare soft-bottoms, seagrass beds, macroalgae meadows and mixed soft-bottoms. It is easy to use and particularly efficient, i.e., 88% of the stations were sampled successfully. We observed 10,007 fish belonging to 172 species, including 45 species targeted by fishermen in New Caledonia, as well as many key species. The results are consistent with the known characteristics of the lagoon soft bottom fish assemblages of New Caledonia. We provide future users with general recommendations and reference plots to estimate the proportion of the theoretical total species richness sampled, according to the number of stations or the duration of the footage.

2016 ◽  
Vol 283 (1844) ◽  
pp. 20160128 ◽  
Author(s):  
Stéphanie D'agata ◽  
Laurent Vigliola ◽  
Nicholas A. J. Graham ◽  
Laurent Wantiez ◽  
Valeriano Parravicini ◽  
...  

High species richness is thought to support the delivery of multiple ecosystem functions and services under changing environments. Yet, some species might perform unique functional roles while others are redundant. Thus, the benefits of high species richness in maintaining ecosystem functioning are uncertain if functions have little redundancy, potentially leading to high vulnerability of functions. We studied the natural propensity of assemblages to be functionally buffered against loss prior to fishing activities, using functional trait combinations, in coral reef fish assemblages across unfished wilderness areas of the Indo-Pacific: Chagos Archipelago, New Caledonia and French Polynesia. Fish functional diversity in these wilderness areas is highly vulnerable to fishing, explained by species- and abundance-based redundancy packed into a small combination of traits, leaving most other trait combinations (60%) sensitive to fishing, with no redundancy. Functional vulnerability peaks for mobile and sedentary top predators, and large species in general. Functional vulnerability decreases for certain functional entities in New Caledonia, where overall functional redundancy was higher. Uncovering these baseline patterns of functional vulnerability can offer early warning signals of the damaging effects from fishing, and may serve as baselines to guide precautionary and even proactive conservation actions.


Author(s):  
Laurent Wantiez

The spatial and temporal patterns of variation of a tropical soft-bottom fish community sampled by a shrimp trawl and a fish trawl were compared at two sites, North and South Bay, of St Vincent Bay, New Caledonia. Results indicated that the species richness and particularly the species composition were related to the type of trawl. However, the overall density and biomass, species diversity, and evenness did not vary significantly as a function of gear type. The same species dominated the catches of the two trawl types, but differences appeared between density, biomass and mean weight of particular species, calculated from the shrimp and the fish trawl catches. The spatial variations of the community structure were comparable between the two gear types, though the composition of the species assemblages were not the same. Differences appeared for the temporal structures. These differences were insignificant in one of the sampled sites (North Bay), but more important in the other site (South Bay), where species diversity, size range of the individuals, and shape diversity of fishes were more important. However, the major differences between the community structures remained the same, independent of sampling gear type. These results validate studies comparing spatial and temporal patterns of variations in general characteristics (i.e. number of species per haul, density, biomass, species diversity and evenness) of tropical soft-bottom fish communities determined by shrimp and fish demersal otter trawls. This also validates the determination of species assemblages especially spatial assemblages. However, important problems may arise when more particular points are studied, such as species composition of the communities, determination of the characteristic species of the assemblages, or study of a particular species.


2011 ◽  
Vol 43 ◽  
pp. 65-79 ◽  
Author(s):  
O A Jorgensen ◽  
C Hvingel ◽  
M A Treble

Author(s):  
Jose L. Rueda ◽  
Manuel Fernández-Casado ◽  
Carmen Salas ◽  
Serge Gofas

The macrofauna of molluscs associated with soft bottoms in the Bay of Cádiz (southern Spain) was studied monthly from February 1994 to January 1996. The number of species (63) is high for a soft bottom and is related to environmental characteristics (growth of macrophytes) and the biogeographical setting of the studied area. Corbula gibba (∼90%) was the dominant species in this taxocoenosis together with the gastropod Nassarius pygmaeus and the bivalves Pandora inaequivalvis, Parvicardium exiguum and Macoma melo. The most frequent species during the two years was also the bivalve Corbula gibba (100%) followed by the gastropods Nassarius pygmaeus, Tricolia tenuis, Rissoa membranacea and the bivalve Macoma melo. Total abundance of the taxocoenosis in both years reached higher values in spring. The dynamics of the ecological indices such as diversity or evenness, and the species richness showed a similar pattern in both years, with low values of diversity and evenness together with high species richness in spring and summer months and the reverse in autumn and winter. The qualitative correspondence analysis of monthly samples shows an ordination related to seasonality in both studied years, however the values of Jaccard's coefficient do not indicate significant boundaries among the monthly samples. The quantitative correspondence analysis shows an ordination and grouping of samples related to the biology of species, particularly with the recruitment of C. gibba, the dominant species. The existence of similar trends in the structure of the taxocoenoses over both years, and the seasonality highlighted by the qualitative correspondence analysis, seems to indicate a certain stability of the ecosystem.


Ecology ◽  
2005 ◽  
Vol 86 (10) ◽  
pp. 2578-2585 ◽  
Author(s):  
S. Planes ◽  
R. Galzin ◽  
J-P. Bablet ◽  
P. F. Sale

2014 ◽  
Vol 122 ◽  
pp. 105-115 ◽  
Author(s):  
Marion Cuif ◽  
David Michael Kaplan ◽  
Jérôme Lefèvre ◽  
Vincent Martin Faure ◽  
Matthieu Caillaud ◽  
...  

PLoS ONE ◽  
2012 ◽  
Vol 7 (7) ◽  
pp. e40997 ◽  
Author(s):  
Simon Van Wynsberge ◽  
Serge Andréfouët ◽  
Mélanie A. Hamel ◽  
Michel Kulbicki

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