1
|
Andréfouët S, Bruyère O, Le Gendre R, Sangare N, Monaco CJ, Thomas Y, Lo-Yat A. Comparison of in situ black-lipped oyster spat collection and larval dispersal modelling results in semi-closed pearl-farming lagoons of the Tuamotu Archipelago. MARINE POLLUTION BULLETIN 2024; 206:116779. [PMID: 39083909 DOI: 10.1016/j.marpolbul.2024.116779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2024] [Revised: 07/19/2024] [Accepted: 07/23/2024] [Indexed: 08/02/2024]
Abstract
Spat collection of the pearl oyster Pinctada margaritifera in atoll lagoons of French Polynesia is the fundamental sustain of black pearl farming. Spat collection has always yielded variable results in space and time, but obvious signs of steady decreases, even collapses, have emerged in several lagoons. Spat collection materializes the ecological connectivity pathways between wild spawning populations and the location of artificial larval settlement substrates. To assess if oyster larval dispersal modelling could capture such pathways, we compared four six-week long spat collector deployment periods with dispersal simulations in two different lagoons. Spat collectors displayed wide spatial and temporal variations. Numerical modelling and field experiments were generally not in agreement. Although both methods have limitations, they can still approximate each other. But the accuracy of model simulations cannot be ascertained with spat collection data only. Using a SWOT (Strength-Weakness-Opportunities-Threats) analysis, we emphasize the complementarity of both approaches for management decisions.
Collapse
Affiliation(s)
- Serge Andréfouët
- IRD, UMR-9220 ENTROPIE (Institut de Recherche pour le Développement, Université de la Réunion, IFREMER, CNRS, Université de la Nouvelle-Calédonie), BP 49, 98725 Vairao, Tahiti, French Polynesia.
| | - Oriane Bruyère
- IRD, UMR 9220 ENTROPIE (Institut de Recherche pour le Développement, Univ de la Réunion, IFREMER, Univ. Nouvelle-Calédonie, CNRS), BPA5, 98948 Noumea, New Caledonia
| | - Romain Le Gendre
- IFREMER, UMR 9220 ENTROPIE (IRD, Univ. Réunion, IFREMER, Univ. Nouvelle-Calédonie, CNRS), BP 32078, 98897 Nouméa Cedex, New Caledonia
| | - Nathanaël Sangare
- IRD, UMR-9220 ENTROPIE (Institut de Recherche pour le Développement, Université de la Réunion, IFREMER, CNRS, Université de la Nouvelle-Calédonie), BP 49, 98725 Vairao, Tahiti, French Polynesia
| | - Cristián J Monaco
- IFREMER, ILM, IRD, UPF, UMR-241 SECOPOL, F-98725 Vairao, Tahiti, French Polynesia
| | - Yoann Thomas
- IRD, UMR 6539 LEMAR (Univ Brest, CNRS, IRD, Ifremer), F-29280 Plouzane, France
| | - Alain Lo-Yat
- IFREMER, ILM, IRD, UPF, UMR-241 SECOPOL, F-98725 Vairao, Tahiti, French Polynesia
| |
Collapse
|
2
|
Bruyère O, Chauveau M, Le Gendre R, Liao V, Andréfouët S. Larval dispersal of pearl oysters Pinctada margaritifera in the Gambier Islands (French Polynesia) and exploring options for adult restocking using in situ data and numerical modelling. MARINE POLLUTION BULLETIN 2023; 192:115059. [PMID: 37210988 DOI: 10.1016/j.marpolbul.2023.115059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/05/2023] [Accepted: 05/09/2023] [Indexed: 05/23/2023]
Abstract
Black pearl farming is the second source of French Polynesia income after tourism, and Gambier Islands are the main farming sites. Gambier main lagoon contains several sub-lagoons critical for pearl oyster rearing and spat collecting (SC). The Rikitea lagoon, traditionally had good SC rates in the warm season which ensured steady supplies of oysters for black pearl production. However, since 2018, SC has abruptly decreased. To assess the factors affecting SC, Gambier lagoon hydrodynamics was investigated in 2019-2020 to calibrate a hydrodynamic model and simulate larval dispersal around the SC areas. The model shows the strong wind influence on larval dispersal and accumulation patterns and suggests that windy months in the warm season as it can occur during La Niña episodes can explain recent poor SC. Larval dispersal scenarios also informed on best locations to perform adult oyster restocking, a practice that can also enhance SC on the long term.
Collapse
Affiliation(s)
- Oriane Bruyère
- IRD, UMR 9220 ENTROPIE (Institut de Recherche pour le Développement, Univ de la Réunion, IFREMER, Univ. Nouvelle-Calédonie, CNRS), BPA5, 98948 Noumea, New Caledonia.
| | - Mathilde Chauveau
- IRD, UMR 9220 ENTROPIE (Institut de Recherche pour le Développement, Univ de la Réunion, IFREMER, Univ. Nouvelle-Calédonie, CNRS), BPA5, 98948 Noumea, New Caledonia; EPTB Gardons (Territorial Public Establishment of the Gardons rivers Basin), Nîmes, 30000, France
| | - Romain Le Gendre
- Ifremer, UMR 9220 ENTROPIE (IRD, Univ. Réunion, IFREMER, Univ. Nouvelle-Calédonie, CNRS), BP 32078, 98897 Nouméa Cedex, New Caledonia
| | - Vetea Liao
- Direction des Ressources Marines, BP 20, 98713 Papeete, French Polynesia
| | - Serge Andréfouët
- IRD, UMR 9220 ENTROPIE (Institut de Recherche pour le Développement, Univ de la Réunion, IFREMER, Univ. Nouvelle-Calédonie, CNRS), BPA5, 98948 Noumea, New Caledonia; IRD, UMR-9220 ENTROPIE (Institut de Recherche pour le Développement, Université de la Réunion, IFREMER, CNRS, Université de la Nouvelle-Calédonie), BP 49 Vairao, Tahiti, French Polynesia
| |
Collapse
|
3
|
Violette C, Le Gendre R, Chauveau M, Andréfouët S. A multivariate approach to synthetize large amount of connectivity matrices for management decisions: Application to oyster population restocking in the pearl farming context of Tuamotu Archipelago semi-closed atolls. MARINE POLLUTION BULLETIN 2023; 189:114748. [PMID: 36841211 DOI: 10.1016/j.marpolbul.2023.114748] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 02/15/2023] [Accepted: 02/16/2023] [Indexed: 06/18/2023]
Abstract
In applied ecology, numerical biophysical modelling allows running numerous simulations of spatial connectivity between source and destination locations. To characterize population connectivity, larval dispersal and resulting connectivity matrices can be computed for various forcing conditions of wind, density of spawners, or pelagic larval durations. Here, we investigate a methodology to synthetize meaningfully all numerical experiments performed for three atoll lagoons in the Tuamotu Archipelago pearl farming context. The objective is to identify the best restocking locations that consistently maximize the spread of pearl oyster larval dispersal, considering all forcing conditions. A multivariate generic approach is used to process and synthesize time-series of connectivity matrices and identify afterward with contextual criteria the spawning locations that match a variety of specific connectivity, logistical and ecological criteria. Similar synthesis of large volume of connectivity matrices will likely gain momentum considering the increasing use of numerical models for applied science and population management.
Collapse
Affiliation(s)
- Clémentine Violette
- UMR-9220 ENTROPIE (Institut de Recherche pour le Développement, Université de la Réunion, IFREMER, CNRS, Université de la Nouvelle-Calédonie), BP 49 Vairao, Tahiti, French Polynesia; Bordeaux Sciences Agro, Gradignan 33170, France
| | - Romain Le Gendre
- UMR 9220 ENTROPIE (IFREMER, Institut de Recherche pour le Développement, Université de la Réunion, Université de Nouvelle-Calédonie, Ifremer, Centre National de la Recherche Scientifique, BP 32078, 98897 Noumea Cedex, New Caledonia
| | - Mathilde Chauveau
- UMR-9220 ENTROPIE (Institut de Recherche pour le Développement, Université de la Réunion, IFREMER, CNRS, Université de la Nouvelle-Calédonie), BP A5, 98848 Noumea Cedex, New Caledonia
| | - Serge Andréfouët
- UMR-9220 ENTROPIE (Institut de Recherche pour le Développement, Université de la Réunion, IFREMER, CNRS, Université de la Nouvelle-Calédonie), BP 49 Vairao, Tahiti, French Polynesia; UMR-9220 ENTROPIE (Institut de Recherche pour le Développement, Université de la Réunion, IFREMER, CNRS, Université de la Nouvelle-Calédonie), BP A5, 98848 Noumea Cedex, New Caledonia.
| |
Collapse
|
4
|
Lo-Yat A, Monaco CJ, Thomas Y, Czorlich Y, Le Borgne F, Muylaert M, Le Moullac G, Vanaa V, Beliaeff B, Garen P. Mismatch between the ecological processes driving early life-stage dynamics of bivalves at two contrasting French Polynesian lagoons. MARINE POLLUTION BULLETIN 2022; 183:114099. [PMID: 36088687 DOI: 10.1016/j.marpolbul.2022.114099] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 08/16/2022] [Accepted: 08/29/2022] [Indexed: 06/15/2023]
Abstract
The pearl-farming industry depends mostly on the natural recruitment of pearl oysters. Little is known about the relative influence of different ecological processes on the natural recruitment of pearl oysters across biogeographical scales. Spatio-temporal dynamics of bivalve larvae and spats were described at Ahe and Mangareva, 1500 km apart across French Polynesia. We quantified the effect of candidate environmental predictors on the dynamics of larvae. Both lagoons showed similar temporal dynamics with twice more larvae and 6 times more spat in Ahe. Pinctada maculata spat were more abundant than for P. margaritifera at both lagoons. While the temporal dynamics in larvae abundance were best explained by a positive effect of temperature in Ahe, the dynamics in Mangareva were poorly predicted by the environmental variables, meaning bivalve early-life stages perform better in Ahe than Mangareva suggesting a mismatch between the relevant environmental forces driving larval dynamics at these two contrasting lagoons.
Collapse
Affiliation(s)
- Alain Lo-Yat
- UMR241 Ecosystèmes Insulaires Océaniens (EIO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre du Pacifique, Unité Ressources Marines en Polynésie Française, BP, 49-98725 Taiarapu ouest, Vairao, Tahiti, French Polynesia.
| | - Cristián J Monaco
- UMR241 Ecosystèmes Insulaires Océaniens (EIO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre du Pacifique, Unité Ressources Marines en Polynésie Française, BP, 49-98725 Taiarapu ouest, Vairao, Tahiti, French Polynesia
| | - Yoann Thomas
- IRD LEMAR-IUEM, rue Dumont d'Urville, 29280 Plouzané, France
| | - Yann Czorlich
- UMR241 Ecosystèmes Insulaires Océaniens (EIO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre du Pacifique, Unité Ressources Marines en Polynésie Française, BP, 49-98725 Taiarapu ouest, Vairao, Tahiti, French Polynesia
| | - Florian Le Borgne
- UMR241 Ecosystèmes Insulaires Océaniens (EIO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre du Pacifique, Unité Ressources Marines en Polynésie Française, BP, 49-98725 Taiarapu ouest, Vairao, Tahiti, French Polynesia
| | - Morgan Muylaert
- UMR241 Ecosystèmes Insulaires Océaniens (EIO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre du Pacifique, Unité Ressources Marines en Polynésie Française, BP, 49-98725 Taiarapu ouest, Vairao, Tahiti, French Polynesia
| | - Gilles Le Moullac
- UMR241 Ecosystèmes Insulaires Océaniens (EIO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre du Pacifique, Unité Ressources Marines en Polynésie Française, BP, 49-98725 Taiarapu ouest, Vairao, Tahiti, French Polynesia
| | - Vincent Vanaa
- UMR241 Ecosystèmes Insulaires Océaniens (EIO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre du Pacifique, Unité Ressources Marines en Polynésie Française, BP, 49-98725 Taiarapu ouest, Vairao, Tahiti, French Polynesia
| | - Benoît Beliaeff
- UMR241 Ecosystèmes Insulaires Océaniens (EIO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre du Pacifique, Unité Ressources Marines en Polynésie Française, BP, 49-98725 Taiarapu ouest, Vairao, Tahiti, French Polynesia
| | - Pierre Garen
- UMR241 Ecosystèmes Insulaires Océaniens (EIO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre du Pacifique, Unité Ressources Marines en Polynésie Française, BP, 49-98725 Taiarapu ouest, Vairao, Tahiti, French Polynesia
| |
Collapse
|
5
|
André LV, Chinain M, Gatti CMI, Liao V, Van Wynsberge S, Tedesco P, Andréfouët S. A systematic prioritization approach for identifying suitable pearl oyster restocking zones following a mass mortality event in Takaroa Atoll, French Polynesia. MARINE POLLUTION BULLETIN 2022; 176:113472. [PMID: 35219077 DOI: 10.1016/j.marpolbul.2022.113472] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 02/10/2022] [Accepted: 02/14/2022] [Indexed: 05/28/2023]
Abstract
Oyster farming for black pearl production is central in French Polynesia. It is the second source of national income and provides substantial job opportunities, notably in remote atolls. However, this sector has been undermined by successive crises, such as mass-mortalities of wild and farmed oyster stocks that have impacted entire lagoons. An option to revive the activity consists of reintroducing oysters in strategic benthic locations selected to maximize reproduction and dispersal of larvae throughout the lagoon, hence promoting recolonization and spat collection for farming. For Takaroa, a Tuamotu atoll recently impacted by mortalities, a systematic prioritization approach identified these restocking sites, using environmental and socio-economic criteria such as: location of suitable habitats for oyster settlement, larval connectivity estimated from hydrodynamic circulation model, farming waste accumulation, and opportunity cost to fishers and farmers who lose access to restocking areas. This approach provides managers with a portfolio of restocking options.
Collapse
Affiliation(s)
- Laure Vaitiare André
- IRD Institut de Recherche pour le Développement - France, UMR 9220 Entropie, (Institut de Recherche pour le Développement - France, Université de la Réunion, Université de la Nouvelle-Calédonie, Ifremer, Centre National de la Recherche Scientifique), BP A5, 98848 Nouméa cedex, New Caledonia; SU Sorbonne Université, 21, rue de l'école de médecine, 75006 Paris, France.
| | - Mireille Chinain
- ILM Institut Louis Malardé, Laboratoire des Biotoxines Marines, UMR 241 EIO, (Ifremer, Institut Louis Malardé, Institut de Recherche pour le Développement, Université de la Polynésie française), BP 30, 98713 Papeete, Tahiti, French Polynesia
| | - Clémence M I Gatti
- ILM Institut Louis Malardé, Laboratoire des Biotoxines Marines, UMR 241 EIO, (Ifremer, Institut Louis Malardé, Institut de Recherche pour le Développement, Université de la Polynésie française), BP 30, 98713 Papeete, Tahiti, French Polynesia
| | - Vetea Liao
- DRM Direction des Ressources Marines, Fare Ute, BP 20, 98713 Papeete, Tahiti, French Polynesia
| | - Simon Van Wynsberge
- Ifremer Institut Français de Recherche pour l'Exploitation de la Mer, UMR 9220 Entropie, (Institut de Recherche pour le Développement - France, Université de la Réunion, Université de la Nouvelle-Calédonie, Ifremer, Centre National de la Recherche Scientifique), BP A5, 98848 Nouméa cedex, New Caledonia
| | - Pauline Tedesco
- Ifremer Institut Français de Recherche pour l'Exploitation de la Mer, DYNECO/PHYSED, BP 70, 29280 Plouzané, France
| | - Serge Andréfouët
- IRD Institut de Recherche pour le Développement - France, UMR 9220 Entropie, (Institut de Recherche pour le Développement - France, Université de la Réunion, Université de la Nouvelle-Calédonie, Ifremer, Centre National de la Recherche Scientifique), BP A5, 98848 Nouméa cedex, New Caledonia
| |
Collapse
|
6
|
Seceh C, Pinazo C, Rodier M, Lajaunie-Salla K, Mazoyer C, Grenz C, Le Gendre R. Biogeochemical model of nitrogen cycling in Ahe (French Polynesia), a South Pacific coral atoll with pearl farming. MARINE POLLUTION BULLETIN 2021; 169:112526. [PMID: 34087667 DOI: 10.1016/j.marpolbul.2021.112526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 05/07/2021] [Accepted: 05/16/2021] [Indexed: 06/12/2023]
Abstract
A biogeochemical model (ECO3M-Atoll) was configured to simulate the lower food web in Ahe Atoll lagoon where phytoplankton is mostly nitrogen limited. Understanding the dynamics of phytoplankton - the main food source for oysters - is crucial for the management and the allocation of new pearl farming sites. After parametrizing the model with in situ observations, we tested different hypotheses about nitrogen cycling (benthic remineralization, atmospheric N fixation, etc.) and compared the results to a large observational dataset. Model results show that simulated (pico- and nano-) phytoplankton biomass and nitrogen concentrations are close to in situ data. The simulated biogeochemical processes (uptake and primary production) are also very similar to the observed values. In the model, primary production ranged from 1.00 to 2.00 mg C m-3 h-1 for pico- and 0.40 to 1.00 mg C m-3 h-1 for nanophytoplankton; mean N uptake was 2.02 μmol N m-3 h-1 for pico- and 1.25 μmol N m-3 h-1 for nanophytoplankton.
Collapse
Affiliation(s)
- C Seceh
- Mediterranean Institute of Oceanography, Aix Marseille Univ., Université de Toulon, CNRS, IRD, MIO UM 110, 13288 Marseille, France.
| | - C Pinazo
- Mediterranean Institute of Oceanography, Aix Marseille Univ., Université de Toulon, CNRS, IRD, MIO UM 110, 13288 Marseille, France
| | - M Rodier
- Mediterranean Institute of Oceanography, Aix Marseille Univ., Université de Toulon, CNRS, IRD, MIO UM 110, 13288 Marseille, France
| | - K Lajaunie-Salla
- Mediterranean Institute of Oceanography, Aix Marseille Univ., Université de Toulon, CNRS, IRD, MIO UM 110, 13288 Marseille, France
| | - C Mazoyer
- Mediterranean Institute of Oceanography, Aix Marseille Univ., Université de Toulon, CNRS, IRD, MIO UM 110, 13288 Marseille, France
| | - C Grenz
- Mediterranean Institute of Oceanography, Aix Marseille Univ., Université de Toulon, CNRS, IRD, MIO UM 110, 13288 Marseille, France
| | - R Le Gendre
- IFREMER, UMR9220 ENTROPIE, IRD, IFREMER, Université de la Réunion, CNRS, Université de Nouvelle-Calédonie, BP 32078, 98897 Nouméa, New Caledonia
| |
Collapse
|
7
|
Andréfouët S, Le Gendre R, Thomas Y, Lo-Yat A, Reisser CMO. Understanding connectivity of pearl oyster populations within Tuamotu atoll semi-closed lagoons: Cumulative insight from genetics and biophysical modelling approaches. MARINE POLLUTION BULLETIN 2021; 167:112324. [PMID: 33839573 DOI: 10.1016/j.marpolbul.2021.112324] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 03/22/2021] [Accepted: 03/23/2021] [Indexed: 06/12/2023]
Abstract
Connectivity affects species demography, (meta)population dynamics, evolution, phylogeny and biogeography. Various methodological approaches are applied to measure connectivity. Biophysical modelling can explore systematically the influence of atmospheric, oceanic and ecological forcing, while genetics measures connectivity patterns within the sampling strategy limit. In the Pacific Ocean pearl farming lagoons, the activity relies on spat collecting of the black lipped pearl oyster Pinctada margaritifera occurring after the larval dispersal phase, which follows spawning from wild or farmed populations. Biophysical 3D modelling and genomic studies have both separately brought insights on within-lagoon connectivity and on the origin of spats. Here, we combined previous genetics results with new realistic biophysical modelling scenarios to elucidate connectivity in Ahe Atoll lagoon. When combined, we identified the weather sequence likely explaining the realized connectivity observations. We discuss the strengths, weaknesses, opportunities and threats of combining these two approaches considering specific pearl farming demographic connectivity questions.
Collapse
Affiliation(s)
- Serge Andréfouët
- UMR-9220 ENTROPIE (Institut de Recherche pour le Développement, Université de la Réunion, Ifremer, CNRS, Université de la Nouvelle-Calédonie), 101, promenade Roger-Laroque Anse Vata, BP A5, 98848 Noumea, New Caledonia.
| | - Romain Le Gendre
- IFREMER, UMR-9220 ENTROPIE, IRD, Université de la Réunion, CNRS, Université de la Nouvelle-Calédonie, Campus IRD, BP32078, Nouméa, New Caledonia
| | - Yoann Thomas
- Univ Brest, CNRS, IRD, Ifremer, LEMAR, F-29280 Plouzane, France
| | - Alain Lo-Yat
- UMR EIO, IFREMER Centre du Pacifique, Unité RMPF, BP49, Vairao, Tahiti, French Polynesia
| | - Céline M O Reisser
- UMR EIO, IFREMER Centre du Pacifique, Unité RMPF, BP49, Vairao, Tahiti, French Polynesia; MARBEC, Univ Montpellier, CNRS, IFREMER, IRD, Montpellier, France
| |
Collapse
|
8
|
Dutheil C, Andrefouët S, Jullien S, Le Gendre R, Aucan J, Menkes C. Characterization of south central Pacific Ocean wind regimes in present and future climate for pearl farming application. MARINE POLLUTION BULLETIN 2020; 160:111584. [PMID: 32896714 DOI: 10.1016/j.marpolbul.2020.111584] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 08/13/2020] [Accepted: 08/16/2020] [Indexed: 06/11/2023]
Abstract
In the South Pacific (SP) pearl farming atolls, wind is the main driver of lagoon water circulation, affecting dispersal and survival of pearl oyster larvae. To characterize typical wind conditions in the SP, wind regime classifications are performed from regional climate simulations using the WRF model, for present-day and for the end of the 21st century under RCP8.5 scenario conditions. At the daily time-scale, 4 regimes are identified: a trade-wind, a north-easterly, and two easterly regimes. Their characteristics are driven by large-scale circulation and climate modes of variability. In future projection, all regimes are characterized by a ~15% wind speed increase, while directions and occurrence frequencies undergo marginal changes. At the monthly time-scale that corresponds to pearl oyster pelagic larval duration, nine wind regimes are determined including three regimes with wind reversals. These regimes can be used to model typical lagoon conditions during larval dispersal.
Collapse
Affiliation(s)
- Cyril Dutheil
- Institut de Recherche pour le Développement, UMR 9220 ENTROPIE (Institut de Recherche Pour le Développement, Université de la Réunion, Université de Nouvelle-Calédonie, Ifremer, Centre National de la Recherche Scientifique), BP A5, 98848 Nouméa cedex, New Caledonia; IRD, LOCEAN (UMR 7159), BP A5, 98848 Nouméa cedex, New Caledonia.
| | - S Andrefouët
- Institut de Recherche pour le Développement, UMR 9220 ENTROPIE (Institut de Recherche Pour le Développement, Université de la Réunion, Université de Nouvelle-Calédonie, Ifremer, Centre National de la Recherche Scientifique), BP A5, 98848 Nouméa cedex, New Caledonia
| | - S Jullien
- IFREMER, Univ. Brest, CNRS, IRD, Laboratoire d'Océanographie Physique et Spatiale (LOPS), IUEM, Plouzané, France
| | - R Le Gendre
- IFREMER, Unité de Recherche Lagons, Ecosystèmes et Aquaculture Durable, ENTROPIE (UMR 9220), BP 32078, 98897 Noumea Cedex, New Caledonia
| | - J Aucan
- Institut de Recherche pour le Développement, UMR 9220 ENTROPIE (Institut de Recherche Pour le Développement, Université de la Réunion, Université de Nouvelle-Calédonie, Ifremer, Centre National de la Recherche Scientifique), BP A5, 98848 Nouméa cedex, New Caledonia
| | - C Menkes
- Institut de Recherche pour le Développement, UMR 9220 ENTROPIE (Institut de Recherche Pour le Développement, Université de la Réunion, Université de Nouvelle-Calédonie, Ifremer, Centre National de la Recherche Scientifique), BP A5, 98848 Nouméa cedex, New Caledonia
| |
Collapse
|
9
|
Lal MM, Bosserelle C, Kishore P, Southgate PC. Understanding marine larval dispersal in a broadcast-spawning invertebrate: A dispersal modelling approach for optimising spat collection of the Fijian black-lip pearl oyster Pinctada margaritifera. PLoS One 2020; 15:e0234605. [PMID: 32555587 PMCID: PMC7302709 DOI: 10.1371/journal.pone.0234605] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 05/29/2020] [Indexed: 11/19/2022] Open
Abstract
Fisheries and aquaculture industries worldwide remain reliant on seed supply from wild populations, with their success and sustainability dependent on consistent larval recruitment. Larval dispersal and recruitment in the marine environment are complex processes, influenced by a multitude of physical and biological factors. Biophysical modelling has increasingly been used to investigate dispersal and recruitment dynamics, for optimising management of fisheries and aquaculture resources. In the Fiji Islands, culture of the black-lip pearl oyster (Pinctada margaritifera) is almost exclusively reliant on wild-caught juvenile oysters (spat), through a national spat collection programme. This study used a simple Lagrangian particle dispersal model to investigate current-driven larval dispersal patterns, identify potential larval settlement areas and compare simulated with physical spat-fall, to inform targeted spat collection efforts. Simulations successfully identified country-wide patterns of potential larval dispersal and settlement from 2012–2015, with east-west variations between bi-annual spawning peaks and circulation associated with El Niño Southern Oscillation. Localised regions of larval aggregation were also identified and compared to physical spat-fall recorded at 28 spat collector deployment locations. Significant and positive correlations at these sites across three separate spawning seasons (r(26) = 0.435; r(26) = 0.438; r(26) = 0.428 respectively, p = 0.02), suggest high utility of the model despite its simplicity, for informing future spat collector deployment. Simulation results will further optimise black-lip pearl oyster spat collection activity in Fiji by informing targeted collector deployments, while the model provides a versatile and highly informative toolset for the fishery management and aquaculture of other marine taxa with similar life histories.
Collapse
Affiliation(s)
- Monal M. Lal
- Australian Centre for Pacific Islands Research, School of Science and Engineering, University of the Sunshine Coast, Maroochydore, Queensland, Australia
- School of Marine Studies, Faculty of Science, Technology and Environment, University of the South Pacific, Suva, Fiji Islands
- * E-mail:
| | - Cyprien Bosserelle
- National Institute of Water and Atmospheric Research, Christchurch, New Zealand
- Geoscience, Energy and Maritime Division, Pacific Community (SPC), Nabua, Suva, Fiji Islands
| | - Pranesh Kishore
- Australian Centre for Pacific Islands Research, School of Science and Engineering, University of the Sunshine Coast, Maroochydore, Queensland, Australia
- School of Marine Studies, Faculty of Science, Technology and Environment, University of the South Pacific, Suva, Fiji Islands
| | - Paul C. Southgate
- Australian Centre for Pacific Islands Research, School of Science and Engineering, University of the Sunshine Coast, Maroochydore, Queensland, Australia
| |
Collapse
|
10
|
Population Connectivity and Genetic Assessment of Exploited and Natural Populations of Pearl Oysters within a French Polynesian Atoll Lagoon. Genes (Basel) 2020; 11:genes11040426. [PMID: 32326599 PMCID: PMC7230779 DOI: 10.3390/genes11040426] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/09/2020] [Accepted: 04/13/2020] [Indexed: 11/17/2022] Open
Abstract
In French Polynesia, the production and exportation of black pearls through the aquaculture of the black-lip pearl oyster Pinctada margaritifera provide the second largest economic income for the country after tourism. This industry entirely relies on the collection of natural spats from few highly recruiting lagoons. In recent years, pearl oyster producers have experienced variable success rates in spat collection, with significant spatial and temporal variability in spat supply, driving uncertainty in the future of pearl production. This study combines, for the first time in a farmed lagoon, genetic (SNPs), demographic (sex ratio, age), and biophysical data (larval dispersal modelling) to shed new light on population dynamics, connectivity, and spat recruitment in Ahe Atoll, a well-studied pearl farming site. Our results indicate that the geographical structuring of the natural populations and the contribution of both natural and exploited stocks to the production of spats result from the interaction of hydrodynamic features, life history traits and demographic parameters: the northeastern natural populations are older, not well connected to the southwestern natural populations and are not replenished by larvae produced by adjacent exploited populations. Moreover, we observe that the exploited populations did not contribute to larval production during our experiment, despite a sampling period set during the most productive season for spat collection. This is likely the result of a strong male bias in the exploited populations, coupled with a sweepstakes reproductive strategy of the species. Our results warrant further investigations over the future of the northeastern older natural populations and a reflection on the current perliculture techniques.
Collapse
|
11
|
Van Wynsberge S, Andréfouët S, Gaertner-Mazouni N, Remoissenet G. Consequences of an uncertain mass mortality regime triggered by climate variability on giant clam population management in the Pacific Ocean. Theor Popul Biol 2017; 119:37-47. [PMID: 29158140 DOI: 10.1016/j.tpb.2017.10.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 08/18/2017] [Accepted: 10/26/2017] [Indexed: 10/18/2022]
Abstract
Despite actions to manage sustainably tropical Pacific Ocean reef fisheries, managers have faced failures and frustrations because of unpredicted mass mortality events triggered by climate variability. The consequences of these events on the long-term population dynamics of living resources need to be better understood for better management decisions. Here, we use a giant clam (Tridacna maxima) spatially explicit population model to compare the efficiency of several management strategies under various scenarios of natural mortality, including mass mortality due to climatic anomalies. The model was parameterized by in situ estimations of growth and mortality and fishing effort, and was validated by historical and new in situ surveys of giant clam stocks in two French Polynesia lagoons. Projections on the long run (100 years) suggested that the best management strategy was a decrease of fishing pressure through quota implementation, regardless of the mortality regime considered. In contrast, increasing the minimum legal size of catch and closing areas to fishing were less efficient. When high mortality occurred due to climate variability, the efficiency of all management scenarios decreased markedly. Simulating El Niño Southern Oscillation event by adding temporal autocorrelation in natural mortality rates increased the natural variability of stocks, and also decreased the efficiency of management. These results highlight the difficulties that managers in small Pacific islands can expect in the future in the face of global warming, climate anomalies and new mass mortalities.
Collapse
Affiliation(s)
- Simon Van Wynsberge
- Institut de Recherche pour le Développement, UMR 9220 ENTROPIE (Institut de Recherche Pour le Développement, Université de la Réunion, Centre National de la Recherche Scientifique). Centre IRD de Tahiti, Chemin de l'Arahiri, pk 3.5, 98713 Arue, BP 529, 98713 Papeete, Tahiti, French Polynesia; Université de la Polynésie Française, UMR-241 EIO (Université de la Polynésie française, Institut Français de Recherche pour l'Exploitation de la MER, Institut de Recherche pour le Développement, Institut Louis Malardé), Laboratoire d'Excellence CORAIL, BP 6570, 98702 Faa'a, Tahiti, French Polynesia.
| | - Serge Andréfouët
- Institut de Recherche pour le Développement, UMR 9220 ENTROPIE (Institut de Recherche Pour le Développement, Université de la Réunion, Centre National de la Recherche Scientifique). Centre IRD de Nouméa, 101 Promenade Roger Laroque, 98848 Nouméa, New Caledonia
| | - Nabila Gaertner-Mazouni
- Université de la Polynésie Française, UMR-241 EIO (Université de la Polynésie française, Institut Français de Recherche pour l'Exploitation de la MER, Institut de Recherche pour le Développement, Institut Louis Malardé), Laboratoire d'Excellence CORAIL, BP 6570, 98702 Faa'a, Tahiti, French Polynesia
| | - Georges Remoissenet
- Direction des Ressources Marines et Minières, Fare Ute, Immeuble Le caill, BP 20, 98713 Papeete, Tahiti, French Polynesia
| |
Collapse
|
12
|
Postaire B, Gélin P, Bruggemann JH, Magalon H. One species for one island? Unexpected diversity and weak connectivity in a widely distributed tropical hydrozoan. Heredity (Edinb) 2017; 118:385-394. [PMID: 28177325 DOI: 10.1038/hdy.2016.126] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 10/03/2016] [Accepted: 11/05/2016] [Indexed: 11/09/2022] Open
Abstract
Isolation by distance (IBD) is one of the main modes of differentiation in marine species, above all in species presenting low dispersal capacities. This study reports the genetic structuring in the tropical hydrozoan Lytocarpia brevirostris α (sensu Postaire et al, 2016b), a brooding species, from 13 populations in the Western Indian Ocean (WIO) and one from New Caledonia (Tropical Southwestern Pacific). At the local scale, populations rely on asexual propagation at short distance, which was not found at larger scales; identical genotypes were restricted to single populations. After the removal of repeated genotypes, all populations presented significant positive FIS values (between 0.094*** and 0.335***). Gene flow was extremely low at all spatial scales, between sites within islands (<10 km distance) and among islands (100 to>11 000 km distance), with significant pairwise FST values (between 0.012*** and 0.560***). A general pattern of IBD was found at the Indo-Pacific scale, but also within sampled ecoregions of the WIO province. Clustering analyses identified each sampled island as an independent population, whereas analysis of molecular variance indicated that population genetic differentiation was significant at small (within island) and intermediate (among islands within province) spatial scales. The high population differentiation might reflect the life cycle of this brooding hydrozoan, possibly preventing regular dispersal at distances more than a few kilometres and probably leading to high cryptic diversity, each island housing an independent evolutionary lineage.
Collapse
Affiliation(s)
- B Postaire
- Université de La Réunion, UMR ENTROPIE Université de La Réunion-CNRS-IRD, Saint Denis, France.,Laboratoire d'Excellence CORAIL, Perpignan, France
| | - P Gélin
- Université de La Réunion, UMR ENTROPIE Université de La Réunion-CNRS-IRD, Saint Denis, France.,Laboratoire d'Excellence CORAIL, Perpignan, France
| | - J H Bruggemann
- Université de La Réunion, UMR ENTROPIE Université de La Réunion-CNRS-IRD, Saint Denis, France.,Laboratoire d'Excellence CORAIL, Perpignan, France
| | - H Magalon
- Université de La Réunion, UMR ENTROPIE Université de La Réunion-CNRS-IRD, Saint Denis, France.,Laboratoire d'Excellence CORAIL, Perpignan, France
| |
Collapse
|
13
|
Gormley K, Mackenzie C, Robins P, Coscia I, Cassidy A, James J, Hull A, Piertney S, Sanderson W, Porter J. Connectivity and Dispersal Patterns of Protected Biogenic Reefs: Implications for the Conservation of Modiolus modiolus (L.) in the Irish Sea. PLoS One 2015; 10:e0143337. [PMID: 26625263 PMCID: PMC4666665 DOI: 10.1371/journal.pone.0143337] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 11/03/2015] [Indexed: 11/18/2022] Open
Abstract
Biogenic reefs created by Modiolus modiolus (Linnaeus, 1758) (horse mussel reefs) are marine habitats which support high levels of species biodiversity and provide valuable ecosystem services. Currently, M. modiolus reefs are listed as a threatened and/or declining species and habitat in all OSPAR regions and thus are highlighted as a conservation priority under the EU Marine Strategy Framework Directive (MSFD). Determining patterns of larval dispersal and genetic connectivity of remaining horse mussel populations can inform management efforts and is a critical component of effective marine spatial planning (MSP). Larval dispersal patterns and genetic structure were determined for several M. modiolus bed populations in the Irish Sea including those in Wales (North Pen Llŷn), Isle of Man (Point of Ayre) and Northern Ireland (Ards Peninsula and Strangford Lough). Simulations of larval dispersal suggested extant connectivity between populations within the Irish Sea. Results from the genetic analysis carried out using newly developed microsatellite DNA markers were consistent with those of the biophysical model. Results indicated moderately significant differentiation between the Northern Ireland populations and those in the Isle of Man and Wales. Simulations of larval dispersal over a 30 day pelagic larval duration (PLD) suggest that connectivity over a spatial scale of 150km is possible between some source and sink populations. However, it appears unlikely that larvae from Northern Ireland will connect directly with sites on the Llŷn or Isle of Man. It also appears unlikely that larvae from the Llŷn connect directly to any of the other sites. Taken together the data establishes a baseline for underpinning management and conservation of these important and threatened marine habitats in the southern part of the known range.
Collapse
Affiliation(s)
- Kate Gormley
- School of Life Sciences, Heriot-Watt University, Riccarton, Edinburgh, EH14 4AS
| | - Clara Mackenzie
- School of Life Sciences, Heriot-Watt University, Riccarton, Edinburgh, EH14 4AS
| | - Peter Robins
- School of Ocean Sciences, Bangor University, Menai Bridge, LL59 5AB
| | - Ilaria Coscia
- Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven, Ch. Deberiotstraat, 32, 3000 Leuven, Belgium
| | - Andrew Cassidy
- Medical Research Institute, University of Dundee, Human Genetics Unit, Ninewells Hospital and Medical School, Dundee, DD1 9SY
| | - Jenny James
- School of Life Sciences, Heriot-Watt University, Riccarton, Edinburgh, EH14 4AS
| | - Angela Hull
- School of the Built Environment, Heriot-Watt University, Riccarton, Edinburgh, EH14 4AS
| | - Stuart Piertney
- The Institute of Biological and Environmental Sciences, Zoology Building, Tillydrone Avenue, Aberdeen, AB24 2TZ
| | - William Sanderson
- School of Life Sciences, Heriot-Watt University, Riccarton, Edinburgh, EH14 4AS
| | - Joanne Porter
- School of Life Sciences, Heriot-Watt University, Riccarton, Edinburgh, EH14 4AS
- * E-mail:
| |
Collapse
|
14
|
Guizien K, Belharet M, Moritz C, Guarini JM. Vulnerability of marine benthic metapopulations: implications of spatially structured connectivity for conservation practice in the Gulf of Lions (NW Mediterranean Sea). DIVERS DISTRIB 2014. [DOI: 10.1111/ddi.12254] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
- K. Guizien
- Laboratoire d'Ecogéochimie des Environnements Benthiques; CNRS, UPMC, UMR8222; Avenue du Fontaulé F-66650 Banyuls-sur-Mer France
| | - M. Belharet
- Laboratoire d'Ecogéochimie des Environnements Benthiques; CNRS, UPMC, UMR8222; Avenue du Fontaulé F-66650 Banyuls-sur-Mer France
| | - C. Moritz
- Laboratoire d'Ecogéochimie des Environnements Benthiques; CNRS, UPMC, UMR8222; Avenue du Fontaulé F-66650 Banyuls-sur-Mer France
| | - J. M. Guarini
- Laboratoire d'Ecogéochimie des Environnements Benthiques; CNRS, UPMC, UMR8222; Avenue du Fontaulé F-66650 Banyuls-sur-Mer France
| |
Collapse
|
15
|
Thomas Y, Dumas F, Andréfouët S. Larval dispersal modeling of pearl oyster Pinctada margaritifera following realistic environmental and biological forcing in Ahe atoll lagoon. PLoS One 2014; 9:e95050. [PMID: 24740288 PMCID: PMC3989291 DOI: 10.1371/journal.pone.0095050] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 03/23/2014] [Indexed: 12/01/2022] Open
Abstract
Studying the larval dispersal of bottom-dwelling species is necessary to understand their population dynamics and optimize their management. The black-lip pearl oyster (Pinctada margaritifera) is cultured extensively to produce black pearls, especially in French Polynesia's atoll lagoons. This aquaculture relies on spat collection, a process that can be optimized by understanding which factors influence larval dispersal. Here, we investigate the sensitivity of P. margaritifera larval dispersal kernel to both physical and biological factors in the lagoon of Ahe atoll. Specifically, using a validated 3D larval dispersal model, the variability of lagoon-scale connectivity is investigated against wind forcing, depth and location of larval release, destination location, vertical swimming behavior and pelagic larval duration (PLD) factors. The potential connectivity was spatially weighted according to both the natural and cultivated broodstock densities to provide a realistic view of connectivity. We found that the mean pattern of potential connectivity was driven by the southwest and northeast main barotropic circulation structures, with high retention levels in both. Destination locations, spawning sites and PLD were the main drivers of potential connectivity, explaining respectively 26%, 59% and 5% of the variance. Differences between potential and realistic connectivity showed the significant contribution of the pearl oyster broodstock location to its own dynamics. Realistic connectivity showed larger larval supply in the western destination locations, which are preferentially used by farmers for spat collection. In addition, larval supply in the same sectors was enhanced during summer wind conditions. These results provide new cues to understanding the dynamics of bottom-dwelling populations in atoll lagoons, and show how to take advantage of numerical models for pearl oyster management.
Collapse
Affiliation(s)
- Yoann Thomas
- Institut de Recherche pour le Développement, unité de recherche CoRéUs, Nouméa, New Caledonia
- * E-mail:
| | - Franck Dumas
- Institut Français de Recherche pour l’Exploitation de la Mer, unité DYNECO, Plouzané, France
| | - Serge Andréfouët
- Institut de Recherche pour le Développement, unité de recherche CoRéUs, Nouméa, New Caledonia
| |
Collapse
|
16
|
Cartier LE, Carpenter KE. The influence of pearl oyster farming on reef fish abundance and diversity in Ahe, French Polynesia. MARINE POLLUTION BULLETIN 2014; 78:43-50. [PMID: 24341945 DOI: 10.1016/j.marpolbul.2013.11.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Revised: 11/06/2013] [Accepted: 11/19/2013] [Indexed: 06/03/2023]
Abstract
Many cultured pearl farms are located in areas of the Pacific that have thriving, highly diverse fish communities but the impacts of farming on these communities are poorly understood. We studied the effects of pearl oyster farming on shore fish abundance and diversity in the lagoon of Ahe, French Polynesia by adapting roving diver census methods to the coral reef bommies of the lagoon and compared 16 sites with high pearl farming impact to others with no direct impact. Pearl farming has a slightly positive effect on reef fish abundance (N) and no significant impact on fish diversity (H) or community composition. This is important when considering the ecological sustainability of pearl farming in French Polynesia and suggests that a potential synergy between pearl farms and marine conservation should be further explored.
Collapse
Affiliation(s)
- Laurent E Cartier
- Department of Environmental Sciences, University of Basel, Bernoullistrasse 30, 4056 Basel, Switzerland.
| | - Kent E Carpenter
- Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529-0266, USA.
| |
Collapse
|
17
|
Andréfouët S, Charpy L, Lo-Yat A, Lo C. Recent research for pearl oyster aquaculture management in French Polynesia. MARINE POLLUTION BULLETIN 2012; 65:407-414. [PMID: 22809827 DOI: 10.1016/j.marpolbul.2012.06.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Indexed: 06/01/2023]
|
18
|
Andréfouët S, Ardhuin F, Queffeulou P, Le Gendre R. Island shadow effects and the wave climate of the Western Tuamotu Archipelago (French Polynesia) inferred from altimetry and numerical model data. MARINE POLLUTION BULLETIN 2012; 65:415-424. [PMID: 22795488 DOI: 10.1016/j.marpolbul.2012.05.042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Revised: 05/25/2012] [Accepted: 05/26/2012] [Indexed: 06/01/2023]
Abstract
To implement a numerical model of atoll lagoon circulation, we characterized first the significant wave height (Hs) regime of the Western Tuamotu Archipelago and the local attenuation due to the protection offered by large atolls in the south Tuamotu. Altimetry satellite data and a WAVEWATCH III two-way nested wave model at 5 km resolution from 2000 to 2010 were used. Correlation between altimetry and model was high (0.88) over the period. According to the wave model, the archipelago inner seas experienced attenuated Hs year-long with a yearly average Hs around 1.3m vs a minimum of 1.6m elsewhere. The island shadow effect is especially significant in the austral winter. In contrast with southern atolls, Western Tuamotu experienced only few days per year of Hs larger than 2.5m generated by very high Hs southern swell, transient western local storms, strong easterly winds, and during the passage of distant hurricanes.
Collapse
|
19
|
Dumas F, Le Gendre R, Thomas Y, Andréfouët S. Tidal flushing and wind driven circulation of Ahe atoll lagoon (Tuamotu Archipelago, French Polynesia) from in situ observations and numerical modelling. MARINE POLLUTION BULLETIN 2012; 65:425-440. [PMID: 22795489 DOI: 10.1016/j.marpolbul.2012.05.041] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Revised: 05/20/2012] [Accepted: 05/21/2012] [Indexed: 06/01/2023]
Abstract
Hydrodynamic functioning and water circulation of the semi-closed deep lagoon of Ahe atoll (Tuamotu Archipelago, French Polynesia) were investigated using 1 year of field data and a 3D hydrodynamical model. Tidal amplitude averaged less than 30 cm, but tide generated very strong currents (2 ms(-1)) in the pass, creating a jet-like circulation that partitioned the lagoon into three residual circulation cells. The pass entirely flushed excess water brought by waves-induced radiation stress. Circulation patterns were computed for climatological meteorological conditions and summarized with stream function and flushing time. Lagoon hydrodynamics and general overturning circulation was driven by wind. Renewal time was 250 days, whereas the e-flushing time yielded a lagoon-wide 80-days average. Tide-driven flush through the pass and wind-driven overturning circulation designate Ahe as a wind-driven, tidally and weakly wave-flushed deep lagoon. The 3D model allows studying pearl oyster larvae dispersal in both realistic and climatological conditions for aquaculture applications.
Collapse
Affiliation(s)
- F Dumas
- Ifremer, DYNECO/PHYSED, BP 70, 29280 Plouzané, France.
| | | | | | | |
Collapse
|
20
|
Rowlands G, Purkis S, Riegl B, Metsamaa L, Bruckner A, Renaud P. Satellite imaging coral reef resilience at regional scale. A case-study from Saudi Arabia. MARINE POLLUTION BULLETIN 2012; 64:1222-37. [PMID: 22480935 DOI: 10.1016/j.marpolbul.2012.03.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 02/21/2012] [Accepted: 03/07/2012] [Indexed: 05/12/2023]
Abstract
We propose a framework for spatially estimating a proxy for coral reef resilience using remote sensing. Data spanning large areas of coral reef habitat were obtained using the commercial QuickBird satellite, and freely available imagery (NASA, Google Earth). Principles of coral reef ecology, field observation, and remote observations, were combined to devise mapped indices. These capture important and accessible components of coral reef resilience. Indices are divided between factors known to stress corals, and factors incorporating properties of the reef landscape that resist stress or promote coral growth. The first-basis for a remote sensed resilience index (RSRI), an estimate of expected reef resilience, is proposed. Developed for the Red Sea, the framework of our analysis is flexible and with minimal adaptation, could be extended to other reef regions. We aim to stimulate discussion as to use of remote sensing to do more than simply deliver habitat maps of coral reefs.
Collapse
Affiliation(s)
- Gwilym Rowlands
- National Coral Reef Institute, Nova Southeastern University, Dania Beach, FL 33004, USA.
| | | | | | | | | | | |
Collapse
|
21
|
Fournier J, Levesque E, Pouvreau S, Le Pennec M, Le Moullac G. Influence of plankton concentration on gametogenesis and spawning of the black lip pearl oyster Pinctada margaritifera in Ahe atoll lagoon (Tuamotu Archipelago, French polynesia). MARINE POLLUTION BULLETIN 2012; 65:463-470. [PMID: 22560741 DOI: 10.1016/j.marpolbul.2012.03.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2011] [Revised: 03/22/2012] [Accepted: 03/28/2012] [Indexed: 05/31/2023]
Abstract
Pearl culture industry represents one of the dominant business sector of French Polynesia. However, it still entirely relies on unpredictable spat collection success. Our aim was to assess the influence of natural plankton concentration fluctuations on maturation and spawning of the black lip pearl oyster Pinctada margaritifera, during a 4 months survey conducted in Ahe atoll lagoon. Plankton concentration was assessed by chlorophyll a extraction and by microscope counts while gonadic index, gonado-visceral dry weights and histology were used to measure pearl oysters reproduction activity. We found that (i) plankton concentration fluctuations were mainly related to wind regime, (ii) gametogenesis rate was mainly related to plankton concentration, (iii) spawning occurred when maximal gonad storage was reached, (iv) plankton concentration was the main spawning synchronizing factor. These results contribute explaining P. margaritifera spat collection variability in French Polynesian atoll lagoon.
Collapse
Affiliation(s)
- Jonathan Fournier
- IFREMER, Centre du Pacifique, BP 7004, 98719 Taravao, Tahiti, French Polynesia
| | | | | | | | | |
Collapse
|
22
|
Pagano M, Sagarra PB, Champalbert G, Bouvy M, Dupuy C, Thomas Y, Charpy L. Metazooplankton communities in the Ahe atoll lagoon (Tuamotu Archipelago, French Polynesia): spatiotemporal variations and trophic relationships. MARINE POLLUTION BULLETIN 2012; 65:538-548. [PMID: 22330075 DOI: 10.1016/j.marpolbul.2012.01.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Revised: 01/06/2012] [Accepted: 01/17/2012] [Indexed: 05/31/2023]
Abstract
Metazooplankton abundance, biomass (<80 μm, 200-500 μm and >500 μm) and community structure in the Ahe atoll were studied together with their relationships with environmental factors (temperature, salinity, wind) and trophic factors (phytoplankton, bacteria, heterotrophic nanoflagellates (HNF) and ciliates) during three periods in 2008-2009. Meroplankton, mainly bivalve and gastropod larvae, was dominant. Holoplankton was dominated by copepods, the main species being Oithona spp., Paracalanus parvus, Clausocalanus spp., Corycaeus spp., Acartia fossae and Undinula vulgaris. The results suggest a clear wind influence on the structure and horizontal distribution of the zooplankton communities. The metazooplankton appeared to be controlled mainly by food resources, suggesting a bottom-up control. The low nanophytoplankton biomass in contrast to the high abundance of picophytoplankton, HNF and nano-particle grazers (mainly Oithona spp., Paracalanus and bivalve larvae) highlighted the importance of the microbial loop in the food web.
Collapse
Affiliation(s)
- Marc Pagano
- Mediterranean Institute of Oceanography (MIO), IRD, UMR 235, 13288 Marseille Cedex 09, France.
| | | | | | | | | | | | | |
Collapse
|
23
|
Thomas Y, Garen P, Bennett A, Le Pennec M, Clavier J. Multi-scale distribution and dynamics of bivalve larvae in a deep atoll lagoon (Ahe, French Polynesia). MARINE POLLUTION BULLETIN 2012; 65:453-462. [PMID: 22248647 DOI: 10.1016/j.marpolbul.2011.12.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 11/27/2011] [Accepted: 12/21/2011] [Indexed: 05/31/2023]
Abstract
Bivalve larvae and hydrographic parameters were sampled over a range of spatio-temporal scales in a deep atoll lagoon. Bivalve larvae abundances were very high throughout the year: 18,550 m(-3) in average. Larvae were (i) concentrated at mid-depth with nocturnal ascent and diurnal descent, (ii) heterogeneously dispersed at the lagoon scale, (iii) subject to day-to-day variation in abundance and (iv) transferred between different parts of the lagoon providing evidence of intra-lagoonal connectivity. The primacy of physical factors was seen on large spatial scale with the diluting effect of water renewal and transfers by hydrodynamics. On smaller spatial scale, the primacy of biological processes was recognised, with larval swimming activity leading to dial vertical migration correlated with food concentration. Variations in larval abundance were driven by bivalve reproductive activity correlated with meteorological conditions (i.e. windy periods). Finally, relationship between bivalve larvae patterns and pearl oyster (Pinctada margaritifera) settlement structuring is discussed.
Collapse
Affiliation(s)
- Y Thomas
- Ifremer, DPFOM LPI, Presqu'île du Vivier, 29840 Argenton, France.
| | | | | | | | | |
Collapse
|